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The University of Electronic Science and Technology of China is a research-intensive university in Chengdu, China. Wikipedia.

Zhu B.,University of Electronic Science and Technology of China
IET Control Theory and Applications | Year: 2014

An extension of previous results concerning the effect of integrators on the closed-loop response overshoot is presented. It is shown that if the open-loop transfer function contains more integrators (i.e. [1/s]) than the Laplace transform of the reference signal, then the resulting output response must exhibit overshoot, assuming that a one degree-of-freedom control configuration is used. Several corollaries are also derived. The obtained results are applicable to minimum and nonminimum phase linear systems, and also strictly proper and non-strictly proper linear systems. A non-overshooting output tracking controller is then proposed for linear chain of integrators, whose structure and performance are analysed. © The Institution of Engineering and Technology 2014.

He Q.,University of Electronic Science and Technology of China | Blum R.S.,Lehigh University
IEEE Signal Processing Letters | Year: 2014

Target position and velocity estimation using a passive radar with multiple signals of opportunity and multiple receive stations is investigated. The maximum likelihood (ML) estimate of the unknown position and velocity vector of a target is presented. Formulas bounding the best possible mean square error are provided, via the Cramer-Rao lower bound, for any unbiased estimator of target position and velocity. The model assumes a single target, a single receive antenna at each receive station, spatially and temporally white Gaussian clutter-plus-noise, and uncorrelated reflection coefficients. To describe the best possible performance, it is assumed that the signals of opportunity are estimated perfectly from the direct path reception. For a specific example where the signals of opportunity come from the Global System for Mobile (GSM) communication system, the optimum possible estimation performance is presented using numerical examples. It is shown that it is possible to obtain large performance gains through using multiple signals of opportunity and multiple receive stations. © 2013 IEEE.

Rao Y.,University of Electronic Science and Technology of China
Photonic Sensors | Year: 2011

This article reviews author's research work on fiber-optic sensors over the last twenty years. It includes two aspects: low-coherence interferometric sensors (LCI) and fiber Bragg grating (FBG) sensors. For LCI sensors, author's work mainly focuses on the interrogation and multiplexing methods for Fizeau and Fabry-Perot interferometric sensors at the University of Kent at Canterbury (UKC), UK, and study on novel Fabry-Perot interferometric sensors and their multiplexing methods at Chongqing University (CQU) and University of Electronic Science & Technology of China (UESTC), China, respectively. For FBG sensors, a number of multiplexing schemes are proposed and demonstrated at UKC, and then novel methods for realization of multi-parameter measurement and long-distance measurement based on the FBG sensor and its combination with other optical fiber sensors are also reported at CQU & UESTC. Thus, author's study on these two topics can be divided into two periods, at UKC and at CQU & UESTC, China. This review is presented in such a time sequence. © The Author(s) 2011.

He W.,National University of Singapore | Ge S.S.,National University of Singapore | Ge S.S.,University of Electronic Science and Technology of China | Zhang S.,National University of Singapore
Automatica | Year: 2011

In this paper, boundary control of a marine installation system is developed to position the subsea payload to the desired set-point and suppress the cable's vibration. Using Hamilton's principle, the flexible cable coupled with vessel and payload dynamics is described as a distributed parameter system with one partial differential equation (PDE) and two ordinary differential equations (ODEs). Adaptive boundary control is proposed at the top and bottom boundaries of the cable, based on Lyapunov's direct method. Considering the system parametric uncertainty, the boundary control schemes developed achieve uniform boundedness of the steady state error between the boundary payload and the desired position. The control performance of the closed-loop system is guaranteed by suitably choosing the design parameters. Simulations are provided to illustrate the applicability and effectiveness of the proposed control. © 2011 Elsevier Ltd. All rights reserved.

Dou F.F.,University of Electronic Science and Technology of China | Hon Y.C.,City University of Hong Kong
Engineering Analysis with Boundary Elements | Year: 2014

Based on kernel-based approximation technique, we devise in this paper an efficient and accurate numerical scheme for solving a backward problem of time-fractional diffusion equation (BTFDE). The kernels used in the approximation are the fundamental solutions of the time-fractional diffusion equation which can be expressed in terms of the M-Wright functions. To stably and accurately solve the resultant highly ill-conditioned system of equations, we successfully combine the standard Tikhonov regularization technique and the L-curve method to obtain an optimal choice of the regularization parameter and the location of source points. Several 1D and 2D numerical examples are constructed to demonstrate the superior accuracy and efficiency of the proposed method for solving both the classical backward heat conduction problem (BHCP) and the BTFDE. © 2013 Elsevier Ltd. All rights reserved.

Liu X.,Southwest University for Nationalities | Liu X.,University of Electronic Science and Technology of China | Yu W.,East China Normal University | Wang L.,Peking University
IEEE Transactions on Automatic Control | Year: 2010

This note addresses the stability problem of continuous-time positive systems with time-varying delays. It is shown that such a system is asymptotically stable for any continuous and bounded delay if and only if the sum of all the system matrices is a Hurwitz matrix. The result is a time-varying version of the widely-known asymptotic stability criterion for constant-delay positive systems. A numerical example illustrates the correctness of our result. © 2006 IEEE.

Hu J.,University of Electronic Science and Technology of China | Hu J.,University of Western Sydney | Zheng W.X.,University of Western Sydney
Automatica | Year: 2014

In this paper, a decentralized adaptive tracking control is developed for a second-order leader-follower system with unknown dynamics and relative position measurements. Linearly parameterized models are used to describe the unknown dynamics of a self-active leader and all followers. A new distributed system is obtained by using the relative position and velocity measurements as the state variables. By only using the relative position measurements, a dynamic output-feedback tracking control together with decentralized adaptive laws is designed for each follower. At the same time, the stability of the tracking error system and the parameter convergence are analyzed with the help of a common Lyapunov function method. Some simulation results are presented to validate the proposed adaptive tracking control. © 2014 Elsevier Ltd. All rights reserved.

Chen H.,University of Electronic Science and Technology of China
Microwave and Optical Technology Letters | Year: 2013

A compact tri-band bandpass filter (BPF) with high isolation and selectivity is proposed in this article, which is based on a tri-mode rectangular open-loop resonator (ROLR) loaded by an open-circuited stub. Characterized by both theoretical analysis and full-wave EM simulation, the proposed resonator is found to have the advantage that the first- and third-mode resonant frequencies can be flexibly controlled by the length of the open-circuited stub, whereas the second-mode resonant frequency is mainly determined by the length of the ROLR. With the multipath propagation mode configuration of the two resonators, the transmission zeros among each passband are generated to improve passband selectivity and achieve high isolation. Theoretical prediction is verified by the experimental result of the proposed tri-band BPF. Copyright © 2013 Wiley Periodicals, Inc.

Raju S.,Hong Kong University of Science and Technology | Wu R.,University of Electronic Science and Technology of China | Chan M.,Hong Kong University of Science and Technology | Yue C.P.,Hong Kong University of Science and Technology
IEEE Transactions on Power Electronics | Year: 2014

This paper presents a compact model of mutual inductance between two planar inductors, which is essential to design and optimize a wireless power transmission system. The tracks of the planar inductors are modeled as constant current carrying filaments, and the mutual inductance between individual filaments is determined by Neumann's integral. The proposed model is derived by solving Neumann's integral using a series expansion technique. This model can predict the mutual inductance at various axial and lateral displacements. Mutual coupling between planar inductors is computed by a 3-D electromagnetic (EM) solver, and the proposed model shows good agreement with these numerical results. Different types of planar inductors were fabricated on a printed circuit board (PCB) or silicon wafer. Using these inductors, wireless power links were constructed for applications like implantable biomedical devices and contactless battery charging systems. Mutual inductance was measured for each of the cases, and the comparison shows that the proposed model can predict mutual coupling suitably. © 1986-2012 IEEE.

Liu Y.,Xiamen University | Liu Q.H.,Duke University | Nie Z.,University of Electronic Science and Technology of China
IEEE Transactions on Antennas and Propagation | Year: 2014

Previously, the matrix pencil method (MPM) and the forward-backward MPM (FBMPM) were used to effectively reduce the number of antenna elements in the single-pattern linear arrays. This work extends the MPM and FBMPM-based synthesis methods to the synthesis of multiple-pattern linear arrays with a smaller number of elements. The extended MPM (resp., the extended FBMPM) method organizes all the multiple pattern data into a composite Hankel (resp., composite Hankel-Toeplitz) matrix from which the minimum number of elements and the common poles corresponding to element positions can be obtained with similar processing used in the original MPM or FBMPM synthesis method. In particular, the extended FBMPM inherits the advantage of the original FBMPM that a useful restriction is put on the distribution of poles, which makes the element positions obtained much more accurate and robust. Numerical experiments are conducted to validate the effectiveness and robustness of the proposed methods. For the tested cases, the element saving is about 20% ~ 25% for reconfigurable shaped patterns, and can be even more for electrically large linear arrays with scanned pencil-beams. © 1963-2012 IEEE.

Ding Y.,Southwest University of Science and Technology | Liu H.,Southwest University of Science and Technology | Cheng J.,University of Electronic Science and Technology of China
ISA Transactions | Year: 2014

The problem of H∞ filtering for a class of discrete-time singular Markovian jump systems with time-varying delays is investigated in this paper. The transition probabilities under consideration are time-varying, i.e., Markovian chain is nonhomogeneous. By using the Lyapunov functional approach and reciprocally convex technique, a less conservative delay-dependent bounded real lemma is developed in terms of linear matrix inequalities. Moreover, a sufficient condition for the existence of the desired filter which guarantees the stochastic admissibility and the H∞ performance index of the resulting filtering error system is presented. Numerical examples are employed to show the usefulness of the proposed results. © 2014 ISA.

Li L.,University of California at Berkeley | Li L.,University of Electronic Science and Technology of China | Gratton C.,University of California at Berkeley | Fabiani M.,University of Illinois at Urbana - Champaign | Knight R.T.,University of California at Berkeley
Neurobiology of Aging | Year: 2013

We investigated age-related changes in frontal and parietal scalp event-related potential (ERP) activity during bottom-up and top-down attention. Younger and older participants were presented with arrays constructed to induce either automatic "pop-out" (bottom-up) or effortful "search" (top-down) behavior. Reaction times (RTs) increased and accuracy decreased with age, with a greater age-related decline in accuracy for the search than for the pop-out condition. The latency of the P300 elicited by the visual search array was shorter in both conditions in the younger than in the older adults. Pop-out target detection was associated with greater activity at parietal than at prefrontal locations in younger participants and with a more equipotential prefrontal-parietal distribution in older adults. Search target detection was associated with greater activity at prefrontal than at parietal locations in older relative to younger participants. Thus, aging was associated with a more prefrontal P300 scalp distribution during the control of bottom-up and top-down attention. Early latency extrastriate potentials were enhanced and N2-posterior-contralateral (N2pc) was reduced in the older group, supporting the idea that the frontal enhancements may be due to a compensation for disinhibition and distraction in the older adults. Taken together these findings provide evidence that younger and older adults recruit different frontal-parietal networks during top-down and bottom-up attention, with older adults increasing their recruitment of a more frontally distributed network in both of these types of attention. This work is in accord with previous neuroimaging findings suggesting that older adults recruit more frontal activity in the service of a variety of tasks than younger adults. © 2013 Elsevier Inc.

Chen X.,University of Electronic Science and Technology of China | Tai A.H.,Hong Kong Polytechnic University | Yang Y.,Zhejiang University
International Journal of Production Research | Year: 2014

In this paper, we consider a production system which is capable to produce two types of products. The first type of products is make-to-order, while the second type is make-to-stock whose demand is satisfied by the on-hand inventory. The demand arrival rates of both types of products are price-sensitive. The excess demand that cannot be satisfied immediately is either backlogged or lost. The system costs include the holding costs of product inventories and shortage costs of unsatisfied demand. The objective is to maximise the total discounted profit over an infinite planning horizon by coordinating the production process and pricing decisions. By analysing the properties of objective functions, we characterise the optimal control policy by two switch curves and the optimal price is also given for different ordering and inventory levels. We also explore the monotonicity of both switch curves which will reduce the computation effort. Numerical experiments are conducted to demonstrate the use of the switch curves in managing the production system and illustrate that compared with the static pricing policy, the optimal integrated price and inventory control policy can result in a significant profit improvement in the make-to-order/make-to-stock system that is much higher than in a single-product system. © 2014 Taylor & Francis.

Yu D.,University of Electronic Science and Technology of China | Parlitz U.,University of Gottingen
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010

A method is presented for system identification of spatially extended systems with structural inhomogeneities of local dynamics and additional long-range links. The proposed identification procedure is based on steady-state stabilization and is illustrated with an inhomogeneous two-dimensional grid of coupled FitzHugh-Nagumo models. © 2010 The American Physical Society.

Xiang Z.,University of Electronic Science and Technology of China
Zeitschrift fur Angewandte Mathematik und Physik | Year: 2010

In this paper, we deal with the global existence and nonexistence of solutions to a diffusive polytropic filtration system with nonlinear boundary conditions. By constructing various kinds of sub- and super-solutions and using the basic properties of M-matrix, we give the necessary and sufficient conditions for global existence of nonnegative solutions, which extend the recent results of Li et al. (Z Angew Math Phys 60:284-298, 2009) and Wang et al. (Nonlinear Anal 71:2134-2140, 2009) to more general equations and simplify their proofs slightly. © 2009 Birkhäuser Verlag Basel/Switzerland.

Cheng Y.,University of Electronic Science and Technology of China
Sensors (Basel, Switzerland) | Year: 2013

In this article, the state-of-the-art multi-wave and hybrid imaging techniques in the field of nondestructive evaluation and structural health monitoring were comprehensively reviewed. A new direction for assessment and health monitoring of various structures by capitalizing the advantages of those imaging methods was discussed. Although sharing similar system configurations, the imaging physics and principles of multi-wave phenomena and hybrid imaging methods are inherently different. After a brief introduction of nondestructive evaluation (NDE) , structure health monitoring (SHM) and their related challenges, several recent advances that have significantly extended imaging methods from laboratory development into practical applications were summarized, followed by conclusions and discussion on future directions.

Xiao M.,University of Electronic Science and Technology of China | Nagamochi H.,Kyoto University
Algorithmica | Year: 2016

The paper presents an O∗(1.2312n)-time and polynomial-space algorithm for the traveling salesman problem in an n-vertex graph with maximum degree 3. This improves all previous time bounds of polynomial-space algorithms for this problem. Our algorithm is a simple branch-and-search algorithm with only one branch rule designed on a cut-circuit structure of a graph induced by unprocessed edges. To improve a time bound by a simple analysis on measure and conquer, we introduce an amortization scheme over the cut-circuit structure by defining the measure of an instance to be the sum of not only weights of vertices but also weights of connected components of the induced graph. © 2015, Springer Science+Business Media New York.

Wang W.-Q.,University of Electronic Science and Technology of China | Wang W.-Q.,Nanjing Southeast University
ISPRS Journal of Photogrammetry and Remote Sensing | Year: 2012

Persistent regional monitoring is particularly valuable in remote sensing applications. Inspired by the advantages of near-space vehicles as compared to satellites and airplanes, this paper presents a regional remote sensing approach by near-space vehicle-borne passive bistatic radars. Note that near-space is defined as the altitude region between 20 and 100. km, which is too high up for conventional airplanes but too low for current satellites. We place passive radar receivers inside near-space vehicles which work in conjunction with opportunistic illuminators such as global positioning system (GPS), spaceborne radar, airborne radar or even ground-based radar as the transmitter, to provide a persistent monitoring. The comparative advantages of near-space vehicle as compared to satellite and airplane are investigated. The system models, signal processing algorithm, synchronization processing technique, and the conceptual design examples are presented. Since experimental data are not available for us, numerical simulation results are provided. Although passive radar is not a new concept, the originality of this paper lies in the matched filter reference signal extraction and synchronization processing algorithms. © 2012 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS).

Xu Y.,Nanyang Technological University | Zhu C.,University of Electronic Science and Technology of China
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2013

In this paper, H.264/AVC primary and redundant slices interlaced multiple description video coding (PRSI-MDVC) is studied due to its high coding efficiency and ease of constructing multiple descriptions by interleaving primary and redundant slices, where the problem of optimal description generation in the rate-distortion sense is addressed. Optimal description generation requires minimization of end-to-end distortion consisting of both source coding distortion determined by quality of primary slices and channel distortion associated with redundant slice coding, subject to a rate constraint. The relevant existing works on the description generation mainly focus on the estimation of channel distortion to determine the amount of inserted redundancy (quality of redundant slices) but ignore the source distortion estimation for the quality of primary slices, thus a comprehensive end-to-end rate-distortion optimization is still unavailable. In this paper, we attack the minimization of the end-to-end distortion by fully exploring temporal coding dependency. Specifically, on one hand, a most recently developed source distortion temporal propagation model is employed to determine coding options of primary slices in the PRSI-MDVC. On the other hand, channel distortion estimation is mainly concerned with the mismatch error estimation when primary slices are lost. Unlike the existing channel distortion estimation approach under the asymptotic fine quantization assumption which is not valid in most practical cases (e.g., at low or medium coding rates), we develop a novel and more feasible estimation scheme, based on which coding parameters of the redundant slices can be better determined. Simulation results show the effectiveness of the proposed frame-level rate-distortion optimized description generation scheme compared with the relevant approaches. © 1991-2012 IEEE.

Zhao R.,University of Electronic Science and Technology of China | Su B.-L.,University of Namur
Materials Letters | Year: 2012

The submicron scale hybrid hollow silica spheres have been fabricated by employing phosphorylated polyethyleneimine as template/scaffold/catalysis in a mild self-assembly biomineralization approach. The highly phosphorylated polyethyleneimine was shown to be a necessary prerequisite for in vitro formation of hollow silica spheres. In the presence of a neutral phosphate buffer, the monovalent anions H 2PO 4 - and divalent anions HPO 4 2 - acted not only as the buffer ions but also as ligands, regulating the shape and morphology of the PEI aggregation, which resulted in the final hollow morphology of silica. The hollow silica particles were very uniform in size, with a diameter of 0.8-1.0 μm and a shell thickness of ~ 70 nm. © 2012 Elsevier B.V. All rights reserved.

Lu L.,Georgia Institute of Technology | Li G.Y.,Georgia Institute of Technology | Wu G.,University of Electronic Science and Technology of China
IEEE Transactions on Wireless Communications | Year: 2013

Cognitive radio (CR) technology has been developed to solve the spectrum-underutilization problem. In CR networks, the CR users have opportunities to access the licensed spectrum bands assigned to the primary users (PUs). Since the PUs have priorities to use the bands, the CR users are not allowed to generate unacceptable interference to them. In this paper, we investigate power allocation schemes for CR networks with both direct and relay-aided transmissions. We first formulate an overall rate optimization problem with interference constraints to the PU and peak power constraints at each node and obtain solutions by theoretical analysis. To take the fairness among CR users into consideration, we further investigate the overall rate optimization problem with an additional sum power constraint and achieve fairness between two CR users by adjusting the sum power threshold. Numerical results are provided to show the impact of the relay node and the PU locations on power allocation solutions. © 2002-2012 IEEE.

Xiong L.,Yunnan Nationalities University | Tian J.,University of Electronic Science and Technology of China | Liu X.,University of Waterloo
Journal of the Franklin Institute | Year: 2012

This paper addresses the problem of the delay-dependent stability for neutral Markovian jump systems with partial information on transition probability. The time delays discussed in this paper are time-varying delays. Combined the new constructed Lyapunov functional with the introduced free matrices, and using the analysis technique of matrix inequalities, the delay-dependent stability conditions are obtained. The obtained results are formulated in terms of LMIs, which can be easily checked in practice by Matlab LMI control toolbox. Three numerical examples are given to show the validity and potential of the developed criteria. © 2012 The Franklin Institute. All rights reserved.

Tang M.-C.,University of Electronic Science and Technology of China | Tang M.-C.,University of Arizona | Tang M.-C.,Chongqing University | Ziolkowski R.W.,University of Arizona
IEEE Transactions on Antennas and Propagation | Year: 2013

The designs and performance characteristics of several electrically small antennas based on complementary split ring resonators (CSRRs) are reported. A coaxial-fed monopole is first integrated with a CSRR that is cut from a grounded finite copper disc. The presence of the electrically small CSRR element facilitates a nearly complete impedance match to the source, a nearly broadside radiation pattern, and a high radiation efficiency. The addition of a circular top-hat to the monopole then achieves an ultra-low profile (0. 005λ0) design and an improved broadside pattern, while maintaining all other desirable features. Finally, to enrich their potential usefulness, two additional enhancements of these designs were accomplished. One is a further miniaturization (ka < 0.5) that is achieved by introducing a more complex CSRR element, while maintaining a high, 82%, radiation efficiency. The second is a further enhancement of the directivity and front-to-back ratio through the introduction of a slot-modified parasitic disc, while maintaining the original impedance matching, low-profile and electrically small properties. These designs were consummated and their performance characteristics evaluated with the frequency domain ANSYS-ANSOFT High Frequency Structure Simulator (HFSS) and were confirmed independently using the time domain CST Microwave Studio (MWS) simulator. A prototype of the basic system was fabricated and tested; the agreement between the simulated and measured results validates the design principles. © 1963-2012 IEEE.

Cheng Y.J.,National University of Singapore | Cheng Y.J.,University of Electronic Science and Technology of China | Bao X.Y.,National University of Singapore | Guo Y.X.,National University of Singapore
IEEE Transactions on Antennas and Propagation | Year: 2013

In this paper, miniaturized substrate integrated multibeam array antennas are proposed and designed at 60 GHz. Owing to the design flexibility of the low temperature cofired ceramic (LTCC) technology, the entire multibeam antenna size is only equal to the size of radiating aperture by carefully embedding the complicated substrate integrated waveguide (SIW) feeding network underneath the radiating array. After introducing design procedures for the folded Butler matrix and the corresponding radiating array, a ±45° dual linear-polarization (LP) and a dual circular-polarization (CP) substrate integrated multibeam array antennas are designed and fabricated, respectively. Here, each multibeam antenna has four switchable beams with different pointing directions. Each beam direction has two orthogonal LP or CP modes, therefore allowing the polarization diversity.Measured results validate our design and demonstrate good performances of our proposed structures. © 2013 IEEE.

Huang H.-Z.,University of Electronic Science and Technology of China
Eksploatacja i Niezawodnosc | Year: 2012

Prediction of structural performance is a complex problem because of the existence of randomness and fuzziness in engineering practice. In this area, reliability analyses have been performed using probabilistic methods. This work investigates reliability analysis of structure involving fuzziness and randomness. In particular, the safety state of the structure is defined by a fuzzy state variable, fuzzy random allowable interval, or fuzzy random generalized strength. Because the membership function of the fuzzy safety state is the key to structural reliability analysis using the fuzzy sets theory, this work proposes useful methods to determine the membership functions and develops a structural reliability analysis method based on the fuzzy safety state. Several examples are provided to illustrate the proposed methods.

Sun X.,University of Electronic Science and Technology of China | Zeng G.,Chengdu University of Technology | Yang H.-C.,Chengdu University of Technology | Li Y.,Chengdu University of Technology
IEEE Antennas and Wireless Propagation Letters | Year: 2012

A novel compact CPW-fed slot antenna for quadband operation is proposed. The antenna is printed on a 25 × 20 mm 2 FR4 substrate with thickness of 1.6 mm and relative permittivity of 4.6. Three L-shaped slots and a rectangular slot are fabricated on the substrate to achieve quadband operation of 2.07-2.77, 3.3-3.8, 5.15-5.35, and 5.7-5.89 GHz. As the four resonant frequencies of antenna are excited by certain parts of the patch respectively, one resonant frequency can be flexibly tuned with little effect on the other. Experimental results demonstrate the good broadside radiation patterns for the four bands and suggest that the proposed antenna is suitable for the M-WiMAX and WLAN applications. © 2012 IEEE.

Hu W.,University of Electronic Science and Technology of China | Yen G.G.,Oklahoma State University
IEEE Transactions on Evolutionary Computation | Year: 2015

Managing convergence and diversity is essential in the design of multiobjective particle swarm optimization (MOPSO) in search of an accurate and well distributed approximation of the true Pareto-optimal front. Largely due to its fast convergence, particle swarm optimization incurs a rapid loss of diversity during the evolutionary process. Many mechanisms have been proposed in existing MOPSOs in terms of leader selection, archive maintenance, and perturbation to tackle this deficiency. However, few MOPSOs are designed to dynamically adjust the balance in exploration and exploitation according to the feedback information detected from the evolutionary environment. In this paper, a novel method, named parallel cell coordinate system (PCCS), is proposed to assess the evolutionary environment including density, rank, and diversity indicators based on the measurements of parallel cell distance, potential, and distribution entropy, respectively. Based on PCCS, strategies proposed for selecting global best and personal best, maintaining archive, adjusting flight parameters, and perturbing stagnation are integrated into a self-adaptive MOPSO (pccsAMOPSO). The comparative experimental results show that the proposed pccsAMOPSO outperforms the other eight state-of-the-art competitors on ZDT and DTLZ test suites in terms of the chosen performance metrics. An additional experiment for density estimation in MOPSO illustrates that the performance of PCCS is superior to that of adaptive grid and crowding distance in terms of convergence and diversity. © 2014 IEEE.

Gao B.,University of Electronic Science and Technology of China | Woo W.L.,Northumbria University | Khor L.C.,Northumbria University
Journal of the Acoustical Society of America | Year: 2014

An unsupervised single channel audio separation method from pattern recognition viewpoint is presented. The proposed method does not require training knowledge and the separation system is based on non-uniform time-frequency (TF) analysis and feature extraction. Unlike conventional research that concentrates on the use of spectrogram or its variants, the proposed separation algorithm uses an alternative TF representation based on the gammatone filterbank. In particular, the monaural mixed audio signal is shown to be considerably more separable in this non-uniform TF domain. The analysis of signal separability to verify this finding is provided. In addition, a variational Bayesian approach is derived to learn the sparsity parameters for optimizing the matrix factorization. Experimental tests have been conducted, which show that the extraction of the spectral dictionary and temporal codes is more efficient using sparsity learning and subsequently leads to better separation performance. © 2014 Acoustical Society of America.

Liu X.-P.,Hefei University of Technology | Liu X.-P.,University of Electronic Science and Technology of China | Chen L.,Hefei University of Technology
Brain Research | Year: 2012

The auditory response to an acoustic stimulus will usually be suppressed, or masked, by a preceding sound. Here, we show that forward acoustic masking at a high frequency can boost the auditory brainstem response (ABR) in rats injected with a high dose of sodium salicylate (NaSal), a tinnitus inducer. The forward narrow band noise caused a decrease in the amplitude of the ABR to a probe tone burst in normal rats, but caused an unexpected increase in the amplitude at 16 kHz in rats treated with NaSal (300 mg/kg). The observed effect could be manifested in normal rats presented with a background tone added to the masker and the probe, suggesting an underlying mechanism associated with tinnitus. We hypothesize that in NaSal-treated rats, tinnitus can internally mask the ABR in a similar way as an external background sound does and the unmasking effect of forward masking can result in a rebound of the otherwise suppressed ABR. Our study raises the possibility of using the ABR as an objective indicator for NaSal-induced tinnitus in animals. This article is part of a Special Issue entitled: Tinnitus Neuroscience. © 2012 Elsevier B.V.

Wu Y.I.,University of Electronic Science and Technology of China | Wong K.T.,Hong Kong Polytechnic University | Lau S.-K.,University of Nebraska at Omaha
IEEE Transactions on Signal Processing | Year: 2010

The acoustic vector-sensor is a practical and versatile sound-measurement system, for applications in-room, open-air, or underwater. Its far-field measurement model has been introduced into signal processing over a decade ago; and many direction-finding algorithms have since been developed for acoustic vector-sensors, but only for far-field sources. Missing in the literature is a near-field measurement model for the acoustic vector-sensor. This correspondence fills this literature gap. © 2010 IEEE.

Zhang T.,University of Electronic Science and Technology of China | Xia N.-G.,University of Delaware
IEEE Transactions on Geoscience and Remote Sensing | Year: 2015

The existing linear-frequency-modulated (or step frequency) and random noise synthetic aperture radar (SAR) systems may correspond to the frequency-hopping and direct-sequence spread spectrum systems in the past second- and third-generation wireless communications. Similar to the current and future wireless communications generations, in this paper, we propose the orthogonal frequency-division multiplexing (OFDM) SAR imaging, where a sufficient cyclic prefix (CP) is added to each OFDM pulse. The sufficient CP insertion converts an intersymbol interference (ISI) channel from multipaths into multiple ISI-free subchannels as the key in a wireless communications system, and analogously, it provides an inter-range-cell interference (IRCI)-free (high range resolution) SAR image in a SAR system. The sufficient CP insertion along with our newly proposed SAR imaging algorithm, particularly for the OFDM signals, also differentiates this paper from all the existing studies in the literature on OFDM radar signal processing. Simulation results are presented to illustrate the high-range-resolution performance of our proposed CP-based OFDM SAR imaging algorithm. © 2014 IEEE.

Zang Y.,University of Washington | Li C.-Z.,University of Washington | Chueh C.-C.,University of Washington | Williams S.T.,University of Washington | And 4 more authors.
Advanced Materials | Year: 2014

High-performance non-fullerene OSCs with PCEs of up to ca. 6.0% are demonstrated based on PBDTT-F-TT polymer and a molecular di-PBI acceptor through comprehensive molecular, interfacial, and device engineering. Impressive PCEs can also be retained in devices with relatively thick BHJ layer and processed through non-halogenated solvents, indicating these high-performance non-fullerene OSCs are promising for large-area printing applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gang L.V.,University of Electronic Science and Technology of China
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science | Year: 2015

A novel pitch curve design method for non-circular bevel gear is presented to simplify design of non-circular bevel gear. Pitch curve equation for non-circular bevel gear is deduced based on geometrical relationships between pitch cone surface of non-circular gear with parallel axis and spherical surface. Then, transmission ratio function is transformed into pitch curve design defects modification equation and mathematical expression between modification factor and pitch curve design parameters for non-circular bevel gear is derived. By using the expression, modification value of pitch curve can be determined rapidly and accurately. Simulation results for high-order elliptical bevel gear and Pascal curve bevel gear demonstrate that the proposed modification method can be applied to pitch curve design for other types of non-circular bevel gear. Design and verification efficiency for non-circular bevel gear are improved effectively by employing the proposed pitch curve design defects modification method. © Institution of Mechanical Engineers.

Hu J.,University of Electronic Science and Technology of China | Chen G.,City University of Hong Kong | Li H.-X.,City University of Hong Kong
Kybernetika | Year: 2011

As embedded microprocessors are applied widerly to multi-agent systems, control scheduling and time-delay problems arose in the case of limited energy and computational ability. It has been shown that the event-triggered actuation strategy is an effective methodology for designing distributed control of multi-agent systems with limited computational resources. In this paper, a tracking control problem of leader-follower multi-agent systems with/without communication delays is formulated and a distributed dynamic tracking control is designed by employing event-triggered technique. Then, the input-to-state stability of the closed-loop multi-agent system with directed interconnections is analyzed. Finally, a numerical example is given to validate the proposed control.

Xiang Y.,University of Electronic Science and Technology of China | Levitin G.,Israel Electric
IEEE Transactions on Reliability | Year: 2012

This paper proposes a new model that generalizes the linear multi-state sliding window system. In this model, the system consists of n linearly ordered multi-state elements. Each element can have different states spanning from complete failure up to perfectly functioning. A performance rate is associated with each state. The system fails if the gap between any pair of groups of r consecutive elements having the cumulative performance lower than a minimum allowable level W is less than m groups of r consecutive elements. An algorithm for system reliability evaluation is suggested which is based on an extended universal moment generating function. Examples of evaluating system reliability and elements' reliability importance indices are presented. © 2012 IEEE.

Wang W.-Q.,University of Electronic Science and Technology of China
International Journal of Antennas and Propagation | Year: 2012

Multiple-input multiple-output (MIMO) synthetic aperture radar (SAR) that employs multiple antennas to transmit orthogonal waveforms and multiple antennas to receive radar echoes is a recently proposed remote sensing concept. It has been shown that MIMO SAR can be used to improve remote sensing system performance. Most of the MIMO SAR research so far focused on signal/data models and corresponding signal processing algorithm. Little work related to MIMO SAR antenna analysis can be found. One of the main advantages of MIMO SAR is that the degrees of freedom can be greatly increased by the concept of virtual antenna array. In this paper, we analyze the virtual antenna array for MIMO SAR high-resolution wide-swath remote sensing applications. The one-dimensional uniform and nonuniform linear antenna arrays are investigated and their application potentials in high-resolution wide-swath remote sensing are introduced. The impacts of nonuniform spatial sampling in the virtual antenna array are analyzed, along with a multichannel filtering-based reconstruction algorithm. Conceptual system and discussions are provided. It is shown that high operation flexibility and reconfigurability can be obtained by utilizing the virtual antenna arrays provided by the MIMO SAR systems, thus enabling a satisfactory remote sensing performance. Copyright © 2012 Wen-Qin Wang.

He W.,National University of Singapore | Ge S.S.,National University of Singapore | Ge S.S.,University of Electronic Science and Technology of China
IEEE Transactions on Control Systems Technology | Year: 2012

In this paper, robust adaptive boundary control is developed for a class of flexible string-type systems under unknown time-varying disturbance. The dynamics of the string system is represented by a nonhomogeneous hyperbolic partial differential equation (PDE) and two ordinary differential equations. Boundary control is proposed at the right boundary of the string based on the original distributed parameter system model (PDE) to suppress the vibration excited by the external unknown disturbance. Adaptive control is designed to compensate the system parametric uncertainty. With the proposed robust adaptive boundary control, all the signals in the closed-loop system are guaranteed to be uniformly ultimately bounded. The state of the string system is proven to converge to a small neighborhood of zero by appropriately choosing design parameters. Simulations are provided to illustrate the effectiveness of the proposed control. © 2006 IEEE.

Qu S.-W.,University of Electronic Science and Technology of China | Ng K.B.,City University of Hong Kong
IEEE Antennas and Wireless Propagation Letters | Year: 2012

A broadband millimeter-wave cavity-backed antenna, excited by a rounded bowtie dipole, is reported in this letter. To improve the radiation patterns and the broadside gains, its aperture is optimized by cutting the sections with higher-order modes at lower frequencies away from a large aperture, forming a specific open cavity structure. Simulations show that the antenna can present an impedance bandwidth from 28 to over 50 GHz for SWR ≤ 2, and a bandwidth from 28 to 49 GHz for -10-dB sidelobe level. Measurements agree reasonably well with simulations. Comparisons between the antennas with and without the improved aperture in terms of electric field distribution and radiation patterns clearly show performance enhancement. © 2011 IEEE.

Qu S.-W.,University of Electronic Science and Technology of China
IEEE Antennas and Wireless Propagation Letters | Year: 2012

A broadband millimeter-wave short backfire antenna with a rounded bowtie exciter is reported in this letter. Simulations and measurements show that the bowtie exciter can provide good illumination to a large antenna aperture, and the elliptical composite cavity can enhance the operating bandwidth to the most extent. Investigations show that the antenna can present a bandwidth from 27.6 to 42.5 GHz for -10-dB sidelobe level (SLL), from 27.6 to over 50 GHz for standing-wave ratio (SWR) ≤ 2, and a broadside gain of 14.3 ∼ 18.2 dBi. Electric field distributions over the antenna aperture are given to clearly show its operating principles. Studies on six critical parameters are performed for practical designs. © 2002-2011 IEEE.

Zhang W.,University of Electronic Science and Technology of China
IEEE Transactions on Communications | Year: 2012

A general theoretical framework is presented for analyzing information transmission over Gaussian channels with memoryless transceiver distortion, which encompasses various nonlinear distortion models including transmit-side clipping, receive-side analog-to-digital conversion, and others. The framework is based on the so-called generalized mutual information (GMI), and the analysis in particular benefits from the setup of Gaussian codebook ensemble and nearest-neighbor decoding, for which it is established that the GMI takes a general form analogous to the channel capacity of undistorted Gaussian channels, with a reduced "effective" signal-to-noise ratio (SNR) that depends on the nominal SNR and the distortion model. When applied to specific distortion models, an array of results of engineering relevance is obtained. For channels with transmitside distortion only, it is shown that a conventional approach, which treats the distorted signal as the sum of the original signal part and a uncorrelated distortion part, achieves the GMI. For channels with output quantization, closed-form expressions are obtained for the effective SNR and the GMI, and related optimization problems are formulated and solved for quantizer design. Finally, super-Nyquist sampling is analyzed within the general framework, and it is shown that sampling beyond the Nyquist rate increases the GMI for all SNR values. For example, with binary symmetric output quantization, information rates exceeding one bit per channel use are achievable by sampling the output at four times the Nyquist rate. © 2012 IEEE.

Zhang Y.,University of Electronic Science and Technology of China | Li L.,University of Swansea
Nano Energy | Year: 2016

Experimental findings on electroluminescence or photoluminescence of ZnO nanowires have been drawn much attention due to their promising applications in many areas. One of the current challenges on this technology is a deeper understanding of this phenomenon in order to adopt it into practical device designs. In this work, a theoretical analysis of the stimulated emission of ZnO nanowires taking into consideration of the piezotronics effect has been conducted using the quantum mechanics theory. It is revealed that extra piezoelectric charges induced by applied mechanical forces increase the overall charge density of the nanowire, subsequently enhancing the emission intensity. Electronic bandgap varying with the diameter of the nanowire determines the peak value in the electromagnetic spectrum. Both wavelength and intensity of the stimulated emission can be tuned by controlling the dimension of the nanowires and external applied mechanical forces. © 2016 Elsevier Ltd.

Reddy V.R.,University of Arkansas | Wu J.,University of Electronic Science and Technology of China | Manasreh M.O.,University of Arkansas
Materials Letters | Year: 2013

Cu(InxGa1-x)Se2 (CIGSe) colloidal nanocrystals growth were accomplished by reacting Cu, In and Ga and Se precursors. The synthesis was performed chemically under inert conditions. The CIGSe nanocrystals were characterized by scanning electron microscopy, energy dispersive analysis X-ray, absorption measurement, and X-ray diffraction. The nanocrystals were deposited directly on anodically grown TiO2 nanotube film to fabricate a nano-heterojunction photovoltaic device. The experiments demonstrate that the TiO2/CIGSe all-inorganic nano-heterojunction solar cell produces some short circuit current and open circuit voltage upon illumination with standard AM 1.5 solar illumination. © 2012 Elsevier B.V.

Xiang Z.,University of Electronic Science and Technology of China | Xiang Z.,CAS Beijing Institute of Applied Physics And Computational Mathematics
Mathematical Methods in the Applied Sciences | Year: 2011

In this paper, by using the Fourier localization technique and Bony's paraproduct decomposition, we give a regularity criterion of the weak solution to 3D viscous Boussinesq equations in Besov spaces. © 2010 John Wiley & Sons, Ltd.

Li T.,CAS Institute of Theoretical Physics | Li T.,University of Electronic Science and Technology of China | Li Z.,Texas A&M University | Nanopoulos D.V.,Texas A&M University | And 2 more authors.
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We show that the quadratic inflation can be realized by the phase of a complex field with helicoid potential. Remarkably, this helicoid potential can be simply realized in minimal supergravity. The global U(1) symmetry of the Kähler potential introduces a flat direction and evades the η problem automatically. So such inflation is technically natural. The phase excursion is super-Planckian as required by the Lyth bound, while the norm of the complex field can be suppressed in the sub-Planckian region. This model resolves the ultraviolet sensitive problem of the large field inflation; besides, it also provides a new type of monodromy inflation in supersymmetric field theory with consistent field stabilization. © 2015 American Physical Society.

Liu Y.,University of Electronic Science and Technology of China | Mei T.,Microsoft
IEEE Transactions on Multimedia | Year: 2011

Visual search reranking is defined as reordering visual documents (images or video clips) based on the initial search results or some auxiliary knowledge to improve the search precision. Conventional approaches to visual search reranking empirically take the "classification performance" as the optimization objective, in which each visual document is determined relevant or not, followed by a process of increasing the order of relevant documents. In this paper, we first show that the classification performance fails to produce a globally optimal ranked list, and then we formulate reranking as an optimization problem, in which a ranked list is globally optimal only if any arbitrary two documents in the list are correctly ranked in terms of relevance. This is different from existing approaches which simply classify a document as "relevant" or not. To find the optimal ranked list, we convert the individual documents to "document pairs," each represented as a "ordinal relation." Then, we find the optimal document pairs which can maximally preserve the initial rank order while simultaneously keeping the consistency with the auxiliary knowledge mined from query examples and web resources as much as possible. We develop two pairwise reranking methods, difference pairwise reranking (DP-reranking) and exclusion pairwise reranking (EP-reranking), to obtain the relevant relation of each document pair. Finally, a round robin criterion is explored to recover the final ranked list. We conducted comprehensive experiments on an automatic video search task over TRECVID 2005-2007 benchmarks, and showed consistent improvements over text search baseline and other reranking approaches. © 2011 IEEE.

Zhang C.,University of Electronic Science and Technology of China | Yi Z.,Sichuan University
Information Sciences | Year: 2011

This paper proposes a novel PSO algorithm, referred to as SFIPSO (Scale-free fully informed particle swarm optimization). In the proposed algorithm a modified Barabási-Albert (BA) model [4] is used as a self-organizing construction mechanism, in order to adaptively generate the population topology exhibiting scale-free property. The swarm population is divided into two subpopulations: the active particles and the inactive particles. The former fly around the solution space to find the global optima; whereas the latter are iteratively activated by the active particles via attaching to them, according to their own degrees, fitness values, and spatial positions. Therefore, the topology will be gradually generated as the construction process and the optimization process progress synchronously. Moreover, the cognitive effect and the social effect on the variance of a particle's velocity vector are distributed by its "contextual fitness" value, and the social effect is further distributed via a time-varying weighted fully informed mechanism that originated from [27]. It is proved by the results of comparative experiments carried out on eight benchmark test functions that the scale-free population topology construction mechanism and the weighted fully informed learning strategy can provide the swarm population with stronger diversity during the convergent process. As a result, SFIPSO obtained success rate of 100% on all of the eight test functions. Furthermore, SFIPSO also yielded good-quality solutions, especially on multimodal test functions. We further test the network properties of the generated population topology. The results prove that (1) the degree distribution of the topology follows power-law, therefore exhibits scale-free property, and (2) the topology exhibits "disassortative mixing" property, which can be interpreted as an important condition for the reinforcement of population diversity. © 2011 Elsevier Inc. All rights reserved.

Guo X.,University of Electronic Science and Technology of China
Sensors and Actuators, B: Chemical | Year: 2014

Use of metallic or magnetic nanoparticles as amplification labels has been proven a good solution for sensing small molecules or analytes at low concentrations which are difficult to detect directly by conventional surface plasmon resonance (SPR) techniques. Here, an amplification approach combining magnetic Fe3O4@Au nanoparticles (GMNPs) and a magnetic field for a SPR immunoassay is presented. A polydimethylsiloxane (PDMS) microfludic channel was mounted on a conventional SPR device to form the SPR sensor chip. An external magnetic field was applied under the SPR sensor chip for rapid delivery of analyte from a sample solution to the sensor surface. The GMNPs were synthesized by growing Au layers on the Fe3O4 surface. The resulting nanoparticles were characterized with scanning electronic microscopy (SEM), UV-vis spectroscopy and magnetometer. The GMNP amplification effect was evaluated by a sandwich immunoassay to detect human Interleukin 17A (IL-17A). The detection results show the proposed amplification approach provides potential to yield a detection limit of 0.05 ng mL-1. © 2014 Elsevier B.V.

Guo J.,CAS Institute of Theoretical Physics | Li J.,University of Adelaide | Li T.,CAS Institute of Theoretical Physics | Li T.,University of Electronic Science and Technology of China | Williams A.G.,University of Adelaide
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

The Galactic center excess is explained in the framework of the Next-to-Minimal Supersymmetric Standard Model with a Z3 discrete symmetry. We show that a resonant CP-odd Higgs boson with mass twice that of the Dark Matter (DM) candidate is favored. Meanwhile, the DM candidate is required to have relatively large coupling with the Z boson through its Higgsino component in order to obtain correct DM relic density. Its LHC discovery potential via four signatures is discussed in detail. We find that the most sensitive signals are provided by the Higgsino-like chargino and neutralino pair production with their subsequent decays into W bosons, Z bosons, and DM. The majority of the relevant parameter space can be probed at the Large Hadron Collider with a center-of-mass energy of 14 TeV and an integrated luminosity 1000 fb-1. © 2015 American Physical Society.

Li T.,CAS Institute of Theoretical Physics | Li T.,University of Electronic Science and Technology of China | Raza S.,CAS Institute of Theoretical Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

Considering the generalized minimal supergravity model in the minimal supersymmetric Standard Model, we study the electroweak supersymmetry, in which the squarks and/or gluino are heavy around a few TeVs while the sleptons, sneutrinos, bino, winos, and/or Higgsinos are light within 1 TeV. We resolve the (g-2)μ/2 discrepancy for the muon anomalous magnetic moment in the Standard Model successfully and identify a parameter space in which such solutions also have the electroweak fine-tuning measures ΔEW 16.5 (6%) and ΔEW 25 (4%) without and with the Wilkinson Microwave Anisotropy Probe (WMAP) bounds, respectively. We find that the allowed mass ranges, which are consistent within 3σ of the g-2 discrepancy, for the lightest neutralino, charginos, stau, stau neutrinos, and first two-family sleptons are [44, 390], [100, 700], [100, 700], [52, 800], and [150, 800] GeV, respectively. Moreover, our solutions satisfy the latest bounds reported by the ATLAS and CMS collaborations on electroweakinos and sleptons. The colored sparticles such as light stop, gluinos, and the first the first two generations of squark masses have been found in the mass ranges of [500, 3000], [1300, 4300], and [1800, 4200] GeV, respectively. To obtain the observed dark matter relic density for the lightest supersymmetric particle (LSP) neutralino, we have the bino-wino, LSP neutralino-stau, and LSP neutralino-tau sneutrinos coannihilation scenarios and the resonance solutions such as the A pole, Higgs pole, and Z pole. We identify the Higgsino-like LSP neutralino and display its spin-independent and spin-dependent cross sections with nucleons. We present ten benchmark points that can be tested at the up coming collider searches as well. © 2015 American Physical Society.

Guo D.,University of Electronic Science and Technology of China | Guo D.,Okinawa Institute of Science and Technology | Li C.,Zhejiang University
Journal of Theoretical Biology | Year: 2012

We systematically investigate the stochastic dynamics of a single Hodgkin-Huxley neuron driven by stochastic excitatory and inhibitory input spikes via unreliable synapses in this paper. Based on the mean-filed theory, a novel intrinsic neuronal noise regulation mechanism stemming from unreliable synapses is presented. Our simulation results show that, under certain conditions, the stochastic resonance phenomenon is able to be induced by the unreliable synaptic transmission, which can be well explained by the theoretical prediction. To a certain degree, the results presented here provide insights into the functional roles of unreliable synapses in neural information processing. © 2012 Elsevier Ltd.

Gu D.,University of Michigan | Gu D.,University of Electronic Science and Technology of China | Zhang C.,University of Michigan | Wu Y.-K.,University of Michigan | Guo L.J.,University of Michigan
ACS Nano | Year: 2014

Rough surface and poor stability of ultrathin Ag films limit their applications in nanophotonic and optoelectronic devices. Here, we report an approach for fabricating ultrasmooth and thermally stable Ag-based thin films on SiO2/Si substrates by Al-doping. The effect of Al-doping on the surface morphology and stability of ultrathin Ag films at room temperature and elevated temperature was investigated. The 15 nm Al-doped Ag films with an Al atomic concentration of 4% have a root-mean-square roughness as low as 0.4 nm. The smooth surface morphology is maintained even after 300 °C annealing in N2. Al-doping enhances the nuclei density of films. Moreover, a capping layer spontaneously formed over the Al-doped Ag films restrains the surface diffusion and mass transportation of Ag atoms. Therefore, Al-doping induces ultrathin Ag films with highly stable and ultrasmooth surface morphology. © 2014 American Chemical Society.

Li X.D.,Nanyang Technological University | Chen T.P.,Nanyang Technological University | Liu Y.,University of Electronic Science and Technology of China | Leong K.C.,Globalfoundries
Optics Express | Year: 2014

The contributions of localized surface plasmon resonance (LSPR) and Drude (free electrons) absorption to the complex dielectric function of ultrathin Au films were investigated with spectroscopic ellipsometry. When the Au film thickness is thinner than ∼10 nm, Au nanoparticles (NPs) are formed as a result of the discontinuity in the films, leading to the emergence of LSPR of Au NPs; and the LSPR exhibits a splitting when the films thinner than ∼8 nm, which could be attributed to the near-field coupling of the Au NPs and/or the inhomogeneous polarizations of the Au NPs. On the other hand, the delocalization of electrons in Au NPs due to the aggregation of Au NPs in a thicker film leads to an increase in the free-electron absorption and a suppression of the LSPR. © 2014 Optical Society of America.

Lin P.,University of Electronic Science and Technology of China | Lin P.,Beihang University | Jia Y.,Beihang University
Automatica | Year: 2011

This paper investigates consensus problems in networks of continuous-time agents with diverse time-delays and jointly-connected topologies. For convergence analysis of the networks, a class of LyapunovKrasovskii functions is constructed which contains two parts: one describes the current disagreement dynamics and the other describes the integral impact of the dynamics of the whole network over the past. By a contradiction approach, sufficient conditions are derived under which all agents reach consensus, even though the communication structures between agents dynamically change over time and the corresponding graphs may not be connected. The obtained conditions are composed of a sum of decoupled parts corresponding to each possible connected component of the communication topology. Finally, numerical examples are included to illustrate the obtained results. Copyright © 2011 Published by Elsevier Ltd. All rights reserved.

Zhou D.,University of Electronic Science and Technology of China
Signal Processing | Year: 2015

A novel dictionary learning algorithm, namely reconstructive and discriminative dictionary learning based on sparse representation classification criterion (RDDLSRCC), is proposed for radar target high resolution range profile (HRRP) recognition in this paper. The core of proposed algorithm is to incorporate the reconstructive power and discriminative power of atoms during the update of atoms. By constructing the objective function based on sparse representation classification criterion (SRCC), the discriminative performance of atoms can be improved while preserving the same-class reconstruction ability of atoms and reducing their reconstruction contribution to other classes. Moreover, the sparse coding coefficients of samples are updated using class-optimal SVD vectors of class-reconstruction residual matrix, thereby accelerating convergence. Compared with other dictionary learning algorithms, RDDLSRCC is more robust to the variation of target aspect and noise's effect. The extensive experimental results on the measured data illustrate that the proposed algorithm achieves a promising target recognition performance. © 2015 Elsevier B.V.

Zhou Y.,University of Electronic Science and Technology of China
Journal of Materials Chemistry A | Year: 2016

Exploring new electrode materials is one of the key solutions to the development of lithium ion batteries. In this work, via density functional theory calculations, we explored the interaction of Li with recently synthesized two-dimensional structures, MX (M = Ge, Sn; X = S, Se) sheets. Our studies revealed the following results: (1) Li atoms can spontaneously and rapidly load onto MX sheets, and finally form a stable configuration with adsorption energies of -1.82, -1.70, -1.76 and -1.86 eV for GeS, GeSe, SnS and SnSe sheets, respectively; (2) the activation barriers of Li atoms along the zigzag direction are about 0.19, 0.26, 0.30 and 0.36 eV for GeS, GeSe, SnS and SnSe sheets, respectively, which can be activated at room temperature; (3) at a relatively large content, MX sheets can still hold Li atoms strongly with very low adsorption energies, effectively insuring the thermodynamic stability of the electrode materials; (4) the results reveal remarkable average voltages, which are about 1.98, 2.12, 2.69 and 2.22 V for GeS, GeSe, SnS and SnSe sheets, respectively; (5) the calculated capacities are about 256, 178, 89 and 136 mA h g-1 for GeS, GeSe, SnS and SnSe sheets, respectively, still larger than those of conventional electrode materials; (6) after lithiation, a semiconductor-to-conductor transition was observed, facilitating the electron movement in the MX sheets. All of these properties successfully show that MX (M = Ge, Sn; X = S, Se) sheets are potential electrode materials for application in high-performance lithium ion batteries. © 2016 The Royal Society of Chemistry.

Zhao T.,University of Electronic Science and Technology of China
Journal of Computational and Theoretical Nanoscience | Year: 2013

Assume we have a set of k colors and we assign an arbitrary subset of these colors to each vertex of a graph G. If we require that each vertex to which an empty set is assigned has in its neighborhood all k colors, then this assignment is called the k-rainbow dominating function of a graph G. The corresponding invariant γrk(G), which is the minimum sum of numbers of assigned colors over all vertices of G, is called the k-rainbow domination number of G. In this paper, we give a tabu search algorithm for finding upper bound for 2-rainbow domination number of generalized Petersen graph P (n,3) for 38 ≤ n ≤ 47 and 3-rainbow domination number of generalized Petersen graph P (n,2) for 5 ≤ n ≤ 24. Copyright © 2013 American Scientific Publishers. All rights reserved.

Gu M.,Pacific Northwest National Laboratory | Wang Z.,Pacific Northwest National Laboratory | Wang Z.,University of Electronic Science and Technology of China | Connell J.G.,Northwestern University | And 4 more authors.
ACS Nano | Year: 2013

Silicon has been widely explored as an anode material for lithium ion battery. Upon lithiation, silicon transforms to amorphous LixSi (a-LixSi) via electrochemical-driven solid-state amorphization. With increasing lithium concentration, a-LixSi transforms to crystalline Li15Si4 (c-Li15Si4). The mechanism of this crystallization process is not known. In this paper, we report the fundamental characteristics of the phase transition of a-LixSi to c-Li15Si4 using in situ scanning transmission electron microscopy, electron energy loss spectroscopy, and density function theory (DFT) calculation. We find that when the lithium concentration in a-LixSi reaches a critical value of x = 3.75, the a-Li3.75Si spontaneously and congruently transforms to c-Li15Si4 by a process that is solely controlled by the lithium concentration in the a-LixSi, involving neither large-scale atomic migration nor phase separation. DFT calculations indicate that c-Li15Si4 formation is favored over other possible crystalline phases due to the similarity in electronic structure with a-Li3.75Si. © 2013 American Chemical Society.

Li J.,University of Sydney | Li J.,University of Electronic Science and Technology of China | Hu T.,University of Sydney | Jackson S.D.,University of Sydney
Optics Letters | Year: 2012

A diode-cladding-pumped dual wavelength Q-switched Ho3+-doped fluoride cascade fiber laser operating in the mid-infrared is demonstrated. Stable pulse trains from the 5I6 → 5I7 and 5I7 → 5I8 laser transitions were produced, and the μs-level time delay between the pulses from each transition was dependent on the pump power. At maximum pump power and at an acousto-optic modulator repetition rate of 25 kHz, the 5I6 → 5I7 transition pulse operated at 3.005 μm, a pulse energy of 29 μJ, and a pulse width of 380 ns; the 5I 7 → 5I8 transition pulse correspondingly produced 7 μJ pulse energy and 260 ns pulse width at 2.074 μm. To the best of our knowledge, this is the first demonstration of a Q-switched fiber laser operating beyond 3 μm. © 2012 Optical Society of America.

Zhou J.,Anhui Xinhua University | Zhou J.,South China Normal University | Yu W.-C.,South China Normal University | Gao Y.-M.,University of Electronic Science and Technology of China | Xue Z.-Y.,South China Normal University
Optics Express | Year: 2015

A cavity QED implementation of the non-adiabatic holonomic quantum computation in decoherence-free subspaces is proposed with nitrogen-vacancy centers coupled commonly to the whispering-gallery mode of a microsphere cavity, where a universal set of quantum gates can be realized on the qubits. In our implementation, with the assistant of the appropriate driving fields, the quantum evolution is insensitive to the cavity field state, which is only virtually excited. The implemented non-adiabatic holonomies, utilizing optical transitions in the Λ type of three-level configuration of the nitrogen-vacancy centers, can be used to construct a universal set of quantum gates on the encoded logical qubits. Therefore, our scheme opens up the possibility of realizing universal holonomic quantum computation with cavity assisted interaction on solid-state spins characterized by long coherence times. © 2015 Optical Society of America.

Zhang Q.-M.,University of Electronic Science and Technology of China | Zeng A.,Hangzhou Normal University | Zeng A.,University of Fribourg | Shang M.-S.,Hangzhou Normal University
PLoS ONE | Year: 2013

Information overload is a serious problem in modern society and many solutions such as recommender system have been proposed to filter out irrelevant information. In the literature, researchers have been mainly dedicated to improving the recommendation performance (accuracy and diversity) of the algorithms while they have overlooked the influence of topology of the online user-object bipartite networks. In this paper, we find that some information provided by the bipartite networks is not only redundant but also misleading. With such "less can be more" feature, we design some algorithms to improve the recommendation performance by eliminating some links from the original networks. Moreover, we propose a hybrid method combining the time-aware and topology-aware link removal algorithms to extract the backbone which contains the essential information for the recommender systems. From the practical point of view, our method can improve the performance and reduce the computational time of the recommendation system, thus improving both of their effectiveness and efficiency. © 2013 Zhang et al.

Vu T.L.,National University of Singapore | Ge S.S.,National University of Singapore | Ge S.S.,University of Electronic Science and Technology of China | Hang C.C.,National University of Singapore
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We exploit the notion of SWM- (simultaneous-weak-measurements)-induced quantum state reduction, enabling the use of measurement backaction to produce the desired quantum states. The probabilistic generation of maximally entangled Bell states and the |GHZ (Greenberger-Horne-Zeilinger) state are then performed as a consequence of this notion. By combining SWM-induced quantum state reduction with feedback control, we are able to deterministically generate any desired Bell state as well as the |GHZ state, without the knowledge of the initial state. The control-computation time is compensated for by the delay time in the time-delay bang-bang control, through which the real-time implementation of the control scheme is guaranteed. The effectiveness of the proposed scheme is illustrated numerically. © 2012 American Physical Society.

Li J.L.-W.,University of Electronic Science and Technology of China
Asia-Pacific Microwave Conference Proceedings, APMC | Year: 2011

The review paper will address briefly the state-of-the-art research and development progresses in the wireless power transmission technology and also potential applications. The review is categorized into two aspects, that is, (a) the long-distance and high-power wireless energy transmission and (b) the short-range and low-power wireless energy transmission. For the long-distance high-power transmission, the review will cover atmospheric effects, high-power microwave generation, transmitting antennas, EMC/EMI effects on radio frequency wireless system, rectennas, and biological effects on human being and animals. For the short-range wireless power transmission, the review will touch inductive couple effects and their applications onto power-grid systems, wireless power charging systems, and medical applications. The review will discuss on advantages and short-comings. © 2011 Engineers Australia.

Zhang Y.,University of Electronic Science and Technology of China | Zhang Y.,University of Minnesota | Zhang F.,University of Minnesota | Zhang F.,Cellectis | And 7 more authors.
Plant Physiology | Year: 2013

The ability to precisely engineer plant genomes offers much potential for advancing basic and applied plant biology. Here, we describe methods for the targeted modification of plant genomes using transcription activator-like effector nucleases (TALENs). Methods were optimized using tobacco (Nicotiana tabacum) protoplasts and TALENs targeting the acetolactate synthase (ALS) gene. Optimal TALEN scaffolds were identified using a protoplast-based single-strand annealing assay in which TALEN cleavage creates a functional yellow fluorescent protein gene, enabling quantification of TALEN activity by flow cytometry. Single-strand annealing activity data for TALENs with different scaffolds correlated highly with their activity at endogenous targets, as measured by high-throughput DNA sequencing of polymerase chain reaction products encompassing the TALEN recognition sites. TALENs introduced targeted mutations in ALS in 30% of transformed cells, and the frequencies of targeted gene insertion approximated 14%. These efficiencies made it possible to recover genome modifications without selection or enrichment regimes: 32% of tobacco calli generated from protoplasts transformed with TALEN-encoding constructs had TALEN-induced mutations in ALS, and of 16 calli characterized in detail, all had mutations in one allele each of the duplicate ALS genes (SurA and SurB). In calli derived from cells treated with a TALEN and a 322-bp donor molecule differing by 6 bp from the ALS coding sequence, 4% showed evidence of targeted gene replacement. The optimized reagents implemented in plant protoplasts should be useful for targeted modification of cells from diverse plant species and using a variety of means for reagent delivery. © 2012 American Society of Plant Biologists. All Rights Reserved.

Li X.D.,Nanyang Technological University | Chen T.P.,Nanyang Technological University | Liu Y.,University of Electronic Science and Technology of China | Leong K.C.,Globalfoundries
Optics Express | Year: 2014

Evolution of dielectric function of Al-doped ZnO (AZO) thin films with annealing temperature is observed. It is shown that the evolution is due to the changes in both the band gap and the free-electron absorption as a result of the change of free-electron concentration of the AZO thin films. The change of the electron concentration could be attributed to the activation of Al dopant and the creation/annihilation of the donor-like defects like oxygen vacancy in the thin films caused by annealing. © 2014 Optical Society of America.

Li Y.,University of Electronic Science and Technology of China | Peng L.,Chengdu University of Information Technology
Journal of Magnetism and Magnetic Materials | Year: 2011

SmCo-based films were deposited on Si (1 0 0) substrates by the rf magnetron sputtering process. The growth conditions are improved for the films deposited on hot Si substrates without the annealing process. The dependence of crystal structure and intrinsic coercivity on substrate temperature is chiefly investigated. It is suggested that TbCu 7 type structural films can be obtained with enhanced in-plane magnetic properties with proper substrate temperature. © 2010 Elsevier B.V. All rights reserved.

Cheng T.,CAS Institute of Theoretical Physics | Li T.,CAS Institute of Theoretical Physics | Li T.,University of Electronic Science and Technology of China | Li T.,Texas A&M University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

To explain all the available experimental results, we have proposed the electroweak supersymmetry (EWSUSY) previously, where the squarks and/or gluino are heavy around a few TeVs while the sleptons, sneutrinos, bino, winos, and/or Higgsinos are light within 1 TeV. In the next to minimal supersymmetric Standard Model, we perform the systematic χ2 analyses on parameter space scan for three EWSUSY scenarios: (I) R-parity conservation and one dark matter candidate, (II) R-parity conservation and multicomponent dark matter, (III) R-parity violation. We obtain the minimal χ2/(degree of freedom) of 10.2/15, 9.6/14, and 9.2/14 respectively for scenarios I, II, and III. Considering the constraints from the LHC neutralino/chargino and slepton searches, we find that the majority of viable parameter space preferred by the muon anomalous magnetic moment has been excluded except for the parameter space with moderate to large tanâ¡β(8). Especially, the most favorable parameter space has relatively large tanâ¡β, moderate λ, small μeff, heavy squarks/gluino, and the second lightest CP-even neutral Higgs boson with mass around 125 GeV. In addition, if the left-handed smuon is nearly degenerate with or heavier than wino, there is no definite bound on wino mass. Otherwise, the wino with mass up to ∼450 GeV has been excluded. Furthermore, we present several benchmark points for scenarios I and II, and briefly discuss the prospects of the EWSUSY searches at the 14 TeV LHC and ILC. © 2013 American Physical Society.

Cheng Y.J.,University of Electronic Science and Technology of China
Asia-Pacific Microwave Conference Proceedings, APMC | Year: 2016

In this paper, several high-gain planar integrated antenna arrays are overviewed. Thanks to their wideband, high-gain and compact configuration, these types of substrate integrated antenna arrays present excellent candidates for millimeter-wave multi-gigahertz capacity wireless systems. © 2015 IEEE.

Wang W.-Q.,University of Electronic Science and Technology of China | Wang W.-Q.,City University of Hong Kong | So H.C.,City University of Hong Kong
IEEE Transactions on Signal Processing | Year: 2014

Different from conventional phased-array, which provides only angle-dependent beampattern, frequency diverse array (FDA) employs a small frequency increment across the antenna elements and results in a range-angle-dependent beampattern. This beampattern offers a potential to localize the targets in two dimensions in terms of slant ranges and azimuth angles. However, it is difficult to obtain the target location information from a standard FDA radar due to the couplings in range and angle responses. In this paper, we propose a transmit subaperturing scheme on the FDA radar for range and angle estimation of targets. The essence is to divide the FDA elements into multiple subarrays and optimize the transmit beamspace matrix with the use of convex optimization. We also discuss several practical issues for designing the FDA radar system parameters. Since the subarrays offer decoupled range and angle responses, the targets can be located using the beamspace-based multiple signal classification algorithm. The range and angle estimation performance is evaluated by comparing with the Cramér-Rao lower bound. © 1991-2012 IEEE.

Bernal R.A.,Northwestern University | Agrawal R.,Northwestern University | Peng B.,Northwestern University | Bertness K.A.,U.S. National Institute of Standards and Technology | And 4 more authors.
Nano Letters | Year: 2011

We characterized the elastic properties of GaN nanowires grown along different crystallographic orientations. In situ transmission electron microscopy tensile tests were conducted using a MEMS-based nanoscale testing system. Complementary atomistic simulations were performed using density functional theory and molecular dynamics. Our work establishes that elasticity size dependence is limited to nanowires with diameters smaller than 20 nm. For larger diameters, the elastic modulus converges to the bulk values of 300 GPa for c-axis and 267 GPa for a- and m-axis. © 2010 American Chemical Society.

Ni D.,University of Electronic Science and Technology of China | Ni D.,University of Windsor | Li K.W.,University of Windsor | Li K.W.,Tokyo Institute of Technology
International Journal of Production Economics | Year: 2012

This research investigates how two supply chain members, a downstream firm (F) and an upstream supplier (S), interact with each other with respect to corporate social responsibility (CSR) behavior and what impact exogenous parameters may have on this interaction. A game-theoretic analysis is conducted to obtain equilibriums for both simultaneous-move and sequential-move CSR games. Under certain assumptions, it is concluded that (1) there exists a mutual incentive between their CSR behavior, whereby a win-win performance in terms of both CSR and profitability is achieved as long as exogenous parameters exceed certain critical thresholds; (2) a higher consumer marginal social-benefit potential (MSBP) or a lower consumer marginal perception difficulty (MPD) helps to lower the critical thresholds of CSR budgets and CSR operational efficiency by S and F, making it easier to achieve the win-win performance; (3) an increase in one supply chain members CSR budget or CSR operational efficiency tends to make the supply chain easier to attain a win-win performance scenario; (4) if CSR decisions are made sequentially, a prior commitment to CSR activities from one supply chain member strengthens the mutual incentive and facilitates the realization of the win-win performance. Business implications of these research findings are also discussed. © 2012 Elsevier B.V. All rights reserved.

Chen W.,Hebei United University | Feng P.,Hebei United University | Lin H.,University of Electronic Science and Technology of China
FEBS Letters | Year: 2012

In this study, we introduced two DNA structural characteristics, namely, bendability and hydroxyl radical cleavage intensity to analyze origin of replication (ORI) in the Saccharomyces cerevisiae genome. We found that both DNA bendability and cleavage intensity in core replication regions were significantly lower than in the linker regions. By using these two DNA structural characteristics, we developed a computational model for ORI prediction and evaluated the model in a benchmark dataset. The predictive performance of the jackknife cross-validation indicates that DNA bendability and cleavage intensity have the ability to describe core replication regions and our model is effective in ORI prediction. © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Chen X.,University of Electronic Science and Technology of China | Chen X.,International Institute For Applied Systems Analysis | Szolnoki A.,Hungarian Academy of Sciences | Szolnoki A.,Institute of Mathematics | Perc M.,University of Maribor
New Journal of Physics | Year: 2014

Cooperators that refuse to participate in sanctioning defectors create the second-order free-rider problem. Such cooperators will not be punished because they contribute to the public good, but they also eschew the costs associated with punishing defectors. Altruistic punishers - those that cooperate and punish - are at a disadvantage, and it is puzzling how such behaviour has evolved. We show that sharing the responsibility to sanction defectors rather than relying on certain individuals to do so permanently can solve the problem of costly punishment. Inspired by the fact that humans have strong but also emotional tendencies for fair play, we consider probabilistic sanctioning as the simplest way of distributing the duty. In well-mixed populations the public goods game is transformed into a coordination game with full cooperation and defection as the two stable equilibria, while in structured populations pattern formation supports additional counterintuitive solutions that are reminiscent of Parrondos paradox. © 2014 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Ziebarth J.D.,University of Tennessee Health Science Center | Bhattacharya A.,University of Tennessee Health Science Center | Chen A.,University of Tennessee Health Science Center | Chen A.,University of Electronic Science and Technology of China | Cui Y.,University of Tennessee Health Science Center
Nucleic Acids Research | Year: 2012

The polymorphism in microRNA target site (PolymiRTS) database aims to identify single-nucleotide polymorphisms (SNPs) that affect miRNA targeting in human and mouse. These polymorphisms can disrupt the regulation of gene expression by miRNAs and are candidate genetic variants responsible for transcriptional and phenotypic variation. The database is therefore organized to provide links between SNPs in miRNA target sites, cis-acting expression quantitative trait loci (eQTLs), and the results of genome-wide association studies (GWAS) of human diseases. Here, we describe new features that have been integrated in the PolymiRTS database, including: (i) polymiRTSs in genes associated with human diseases and traits in GWAS, (ii) polymorphisms in target sites that have been supported by a variety of experimental methods and (iii) polymorphisms in miRNA seed regions. A large number of newly identified microRNAs and SNPs, recently published mouse phenotypes, and human and mouse eQTLs have also been integrated into the database. The PolymiRTS database is available at http://compbio.uthsc.edu/miRSNP/. © The Author(s) 2011.

Lu Q.,University of Electronic Science and Technology of China | Lu Q.,Basque Center for Applied Mathematics
ESAIM - Control, Optimisation and Calculus of Variations | Year: 2013

In this paper, a lower bound is established for the local energy of partial sum of eigenfunctions for Laplace-Beltrami operators (in Riemannian manifolds with low regularity data) with general boundary condition. This result is a consequence of a new pointwise and weighted estimate for Laplace-Beltrami operators, a construction of some nonnegative function with arbitrary given critical point location in the manifold, and also two interpolation results for solutions of elliptic equations with lateral Robin boundary conditions. © 2012 EDP Sciences, SMAI.

Wang W.-Q.,University of Electronic Science and Technology of China
IET Radar, Sonar and Navigation | Year: 2016

Different from phased array providing only angle-dependent transmit beampattern, frequency diverse array (FDA) employs a small frequency increment across its array elements to provide range-angle-dependent transmit beampattern. This enables the array beam to scan without the need of phase shifters or mechanical steering. Since FDA has received much attention in antenna and radar signal processing societies, it is necessary to make an overview on this interesting topic. This study introduces what FDA is and why it could be exploited for radar and navigation applications from a top-level system description and appeal to the radar signal processing and system engineering communities for more investigations on this promising array technique. The status of FDA studies is overviewed and the most recent advances of FDA radar are discussed. The basic FDA system architectures are introduced, along with performance compared to a conventional phased-array. Next, guidelines for choosing good system parameters and typical implementation schemes are provided. Finally, potential applications in range and angle estimation of targets, cognitive FDA radar and low probability of identification FDA radar are discussed, along with several technical challenges. © The Institution of Engineering and Technology 2016.

Liu L.-S.,University of Electronic Science and Technology of China
International Journal of RF and Microwave Computer-Aided Engineering | Year: 2011

A complete empirical large-signal model for the GaAs- and GaN-based HEMTs is presented. Three generalized drain current I-V models characterized by the multi-bias Pulsed I-V measurements are presented along with their dependence on temperature and quiescent bias state. The new I-V equations dedicated for different modeling cases are kept accurate enough to the higher-order derivatives of drain-current. Besides, an improved charge-conservative gate charge Q-V formulation is proposed to extract and model the nonlinear gate capacitances. The composite nonlinear model is shown to accurately predict the S-parameters, large-signal power performances as well as the two-tone intermodulation distortion products for various types of GaAs and GaN HEMTs. © 2011 Wiley Periodicals, Inc.

He Q.,University of Electronic Science and Technology of China | He Q.,Lehigh University | Blum R.S.,Lehigh University | Godrich H.,New Jersey Institute of Technology | Haimovich A.M.,New Jersey Institute of Technology
IEEE Journal on Selected Topics in Signal Processing | Year: 2010

This paper studies the velocity estimation performance for multiple-input multiple-output (MIMO) radar with widely spaced antennas. We derive the Cramer Rao bound (CRB) for velocity estimation and study the optimized system/configuration design based on CRB. General results are presented for an extended target with reflectivity varying with look angle. Then detailed analysis is provided for a simplified case, assuming an isotropic scatterer. For given transmitted signals, optimal antenna placement is analyzed in the sense of minimizing the CRB of the velocity estimation error. We show that when all antennas are located at approximately the same distance from the target, symmetrical placement is optimal and the relative position of transmitters and receivers can be arbitrary under the orthogonal received signal assumption. In this case, it is also shown that for MIMO radar with optimal placement, velocity estimation accuracy can be improved by increasing either the signal time duration or the product of the number of transmit and receive antennas. © 2010 IEEE.

Wang W.-Q.,University of Electronic Science and Technology of China
IEEE Aerospace and Electronic Systems Magazine | Year: 2011

Near-space is defined as the atmospheric region from about 20 kilometer (km) to 100 km above the Earth's surface; near-space vehicles offer several advantages to Low Earth Orbit (LEO) satellites and airplanes because near-space vehicles are not constrained by orbital mechanics and fuel consumption. Some of the near-space vehicle advantages include their potential for some specific radar applications that require persistentiy monitoring or fast-revisiting frequency which are explained herein. The role of near-space vehicles is reviewed in supplying a gap between satellites and airplanes for microwave remote sensing applications. Several potential applications such as passive surveillance, reconnaissance, and high resolution wide swath imaging are described. The novel multiple-input and multiple-output (MIMO)-based multi-aperture in elevation and space-time coding (STC) synthetic aperture radar (SAR) are presented for high resolution wide swath imaging. Therefore, given their operational flexibility, near-space vehicle-borne radars may supply the gap between space-borne and airborne radars which is the reason we appeal to the systems engineering community for more publications and more support on the research and development of near-space vehicle-borne radars. © 2011 IEEE.

Wang W.-Q.,University of Electronic Science and Technology of China | Jiang D.,Northeastern University China
IEEE Sensors Journal | Year: 2014

Due to extreme conditions, the near-space region is vastly underused and can be utilized for various scientific uses. The unconstrained orbital mechanism and low fuel consumption advantages for using synthetic aperture radar over the satellites and airplanes navigation systems make these conditions superior for a wide range of services, monitoring, earth observation, and sensing applications. The augmented integration within the existing global navigation system can help in measuring the direction-of-arrival, as well as collecting and distributing accurate location information. For wireless sensing applications, it can enable a new range of opportunities, a wide range of smart sensor applications as experimental platforms for deployment of new technologies. Here, we also examine the implementation of near-space platform (NSP) coverage and associated technologies. Then, a brief integration of communication and navigation services using NSP from a top-level system description of how to relay, associated complementary systems, including radar sensor systems, satellite systems, and terrestrial networks can be used. © 2001-2012 IEEE.

Levitin G.,University of Electronic Science and Technology of China | Levitin G.,Israel Electric | Hausken K.,University of Stavanger
Reliability Engineering and System Safety | Year: 2013

The paper considers a system consisting of genuine elements and false targets that cannot be distinguished by the attacker's observation. The false targets can be destroyed with much less effort than the genuine elements. To enhance the attack efficiency the attacker uses a double attack strategy in which it tries first to eliminate with optimal effort as many false targets as possible in the first attack and then distributes its entire remaining resource among all surviving targets in the second attack. It is assumed that the defender can protect some of the false targets whereas the attacker attacks all targets it can observe. In both attacks the attacking resource is distributed evenly among the attacked targets. The model for evaluating the system vulnerability in the double attack is suggested for parallel and series systems. This model considers the cases of perfect and imperfect detection of the targets destroyed in the first attack. The defense strategy is analyzed based on a two period minmax game. The methodology of optimal attack and defense strategies analysis is demonstrated. In is shown that under certain conditions (high contest intensity, scarce defense resource, low FT cost, high probability of wrong identification of destroyed targets by the attacker) the defender benefits from protecting a subset of the false targets. An algorithm for determining the optimal number of false targets that should be protected is suggested. © 2012 Elsevier B.V. All rights reserved.

Liu J.,University of California at Los Angeles | Li L.,University of California at Los Angeles | Li L.,University of Electronic Science and Technology of China | Pei Q.,University of California at Los Angeles
Macromolecules | Year: 2011

We demonstrate that conjugated polymers are able to efficiently host blue and white electrophosphorescence if the conjugated polymer has both high triplet energy level (ET) and high-lying HOMO energy level. A novel conjugated polymer host (PmPTPA) is developed by attaching triphenylamine unit to poly(m-phenylene) backbone. The poly(m-phenylene) backbone endows PmPTPA an ET as high as 2.65 eV, which is sufficiently high to prevent triplet energy back transfer. The tethering triphenylamine unit leads to the HOMO energy level of -5.35 eV for PmPTPA and facilitates hole injection. As the result, blue phosphorescent polymer light-emitting diodes (PPLEDs) based on PmPTPA exhibit the luminance efficiency of 17.9 cd/A and external quantum efficiency of 9.3%. White PPLEDs with blue, green and red phosphorescent dopants dispersed in PmPTPA show the luminance efficiency of 22.1 cd/A and external quantum efficiency of 10.6%. For both the blue and white PPLEDs based on the conjugated polymer host PmPTPA, the EL performance are fairly comparable to those of the state-of-the-art nonconjugated polymer host, poly(vinyl-carbazole) (PVK). These results indicate that conjugated polymers are suitable host materials for PPLEDs with all emission colors. © 2011 American Chemical Society.

Liu Z.,University of Electronic Science and Technology of China
IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) | Year: 2013

A simple tridimensional negative permeability metamaterial structure Split Ring Resonator (SRR) based on Low Temperature Co-fired Ceramic (LTCC) substrate is proposed to eliminate mutual coupling between array elements. Embedded SRRs can help in the reduction of mutual coupling by using their capability of suppressing surface waves propagation in a given frequency range. By placing the SRR array between two adjacent microstrip antennas, greater than 15 dB peak isolation is achieved for array elements spacing of 0.2λ0. © 2013 IEEE.

Wang Y.,University of Electronic Science and Technology of China
Mathematical Methods in the Applied Sciences | Year: 2015

This paper deals with the quasilinear Keller-Segel system with rotation ut=∇·(D(u)∇u-uS(u,v,x)∇v),x∈Ω,t>0,vt=Δv-uf(v),x∈Ω,t>0,∇v·ν=0,(D(u)∇u-uS(u,v,x)∇v)·ν=0,x∈∂Ω,t>0, where Ω⊂Rn(n≥2) is a bounded domain with smooth boundary, D(u) is supposed to be sufficiently smooth and satisfies D(u)≥D0um - 1(m≥1) and D(u)≤D1(u + 1)K - mum - 1(K≥1) for all u≥0 with some positive constants D0 and D1, and f(u) is assumed to be smooth enough and non-negative for all u≥0 and f(0) = 0, while S(u,v,x) = (sij)n × n is a matrix with sij∈C2([0,∞)×[0,∞)×Ω-) and |S(u,v,x)|≤ul-2S~(v) with l≥2, where S~(v) is nondecreasing on [0,∞). It is proved that when m>l-2n, the system possesses at least one global and bounded weak solution for any sufficiently smooth non-negative initial data. © 2015 John Wiley & Sons, Ltd.

Xu C.,Liaocheng University | Zhao J.,Liaocheng University | Yu J.,University of Electronic Science and Technology of China | Cui C.,Liaocheng University
Electrochimica Acta | Year: 2013

Two bis(ethylenedioxythiophene)naphthalene monomers 1,4-bis(2-(3,4- ethylenedioxythiophene))-naphthalene (M1) and 2,6-bis(2-(3,4- ethylenedioxythiophene))-naphthalene (M2) were synthesized, and corresponding polymer poly(1,4-bis(2-(3,4-ethylenedioxythiophene))-naphthalene) (P1) and poly(2,6-bis(2-(3,4-ethylenedioxythiophene))-naphthalene) (P2) were electrochemically synthesized and characterized. Characterizations of the resulting polymers were performed by cyclic voltammetry, UV-vis spectroscopy and scanning electron microscopy. The oxidation potential of monomer M2 was lower than that of the M1, and the conjugation lengths of both the M2 and P2 were longer than the corresponding M1 and P1, respectively. Spectroelectrochemical analysis revealed that both the polymer films had good electrochromic properties and exhibited multi-electrochromic behaviors. Besides, the corresponding devices P1/Poly(3,4-ethylenedioxythiophene) (PEDOT) device and P2/PEDOT device showed satisfactory optical contrast (ΔT%), fast response time and excellent cyclic voltammetry stability. The electrochromic properties of two EDOT-naphthalene-EDOT style polymers are dependent on the position of substitution. © 2013 Elsevier Ltd.

Jiang C.,University of Electronic Science and Technology of China | Li H.,Stevens Institute of Technology | Rangaswamy M.,U.S. Air force
IEEE Transactions on Signal Processing | Year: 2012

The conjugate gradient (CG) algorithm is an efficient method for the calculation of the weight vector of the matched filter (MF). As an iterative algorithm, it produces a series of approximations to the MF weight vector, each of which can be used to filter the test signal and form a test statistic. This effectively leads to a family of detectors, referred to as the CG-MF detectors, which are indexed by k the number of iterations incurred. We first consider a general case involving an arbitrary covariance matrix of the disturbance (including interference, noise, etc.) and show that all CG-MF detectors attain constant false alarm rate (CFAR) and, furthermore, are optimum in the sense that the kth CG-MF detector yields the highest output signal-to-interference-and- noise ratio (SINR) among all linear detectors within the k th Krylov subspace. We then consider a structured case frequently encountered in practice, where the covariance matrix of the disturbance contains a low-rank component (rank-r) due to dominant interference sources, a scaled identity due to the presence of a white noise, and a perturbation component containing the residual interference. We show that the (r+1)st CG-MF detector achieves CFAR and an output SINR nearly identical to that of the MF detector which requires complete iterations of the CG algorithm till reaching convergence. Hence, the (r+1)st CG-MF detector can be used in place of the MF detector for significant computational saving when r is small. Numerical results are presented to verify the accuracy of our analysis for the CG-MF detectors. © 1991-2012 IEEE.

Guo X.,Central South University of forestry and Technology | Wang C.,City University of Hong Kong | Zhou Y.,University of Electronic Science and Technology of China
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2013

We investigated the energetic stability, electronic, and magnetic properties of hydrogenated graphene nanoflakes (GNFs) by using density-functional theory (DFT). Hydrogenated GNFs were found to be the stable heterojunction structures. As the increase of H coverage, a transition of a small-gap semiconductor to wide-gap semiconductor occurs, accompanied with a nonmagnetic (with the coverage χ=0) → magnetic (with the coverage 0<χ<1) → nonmagnetic (with the coverage χ=1) transfer for hexagonal nanoflakes and magnetic (with the coverage 0≤χ<1) → nonmagnetic (with the coverage χ=1) transfer for triangular nanoflakes. The efficacious tune of band gaps and the magnetic moments on these nanoflakes by hydrogenation offers an effectual avenue for the applications of C-based nanomagnets. © 2013 Elsevier B.V.

Li X.,University of Electronic Science and Technology of China | Colombo L.,Texas Instruments | Ruoff R.S.,Ulsan National Institute of Science and Technology
Advanced Materials | Year: 2016

Over the past decade, graphene has advanced rapidly as one of the most promising materials changing human life. Development of production-worthy synthetic methodologies for the preparation of various types of graphene forms the basis for its investigation and applications. Graphene can be used in the forms of either microflake powders or large-area thin films. Graphene powders are prepared by the exfoliation of graphite or the reduction of graphene oxide, while graphene films are prepared predominantly by chemical vapor deposition (CVD) on a variety of substrates. Both metal and dielectric substrates have been explored; while dielectric substrates are preferred over any other substrate, much higher quality graphene large-area films have been grown on metal substrates such as Cu. The focus here is on the progress of graphene synthesis on Cu foils by CVD, including various CVD techniques, graphene growth mechanisms and kinetics, strategies for synthesizing large-area graphene single crystals, graphene transfer techniques, and, finally, challenges and prospects are discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dou F.F.,University of Electronic Science and Technology of China | Hon Y.C.,City University of Hong Kong
Engineering Analysis with Boundary Elements | Year: 2012

We investigate in this paper a Cauchy problem for the time-fractional diffusion equation (TFDE). Based on the idea of kernel-based approximation, we construct an efficient numerical scheme for obtaining the solution of a Cauchy problem of TFDE. The use of M-Wright functions as the kernel functions for the approximation space allows us to express the solution in terms of M-Wright functions, whose numerical evaluation can be accurately achieved by applying the inverse Laplace transform technique. To handle the ill-posedness of the resultant coefficient matrix due to the noisy Cauchy data, we adapt the standard Tikhonov regularization technique with the L-curve method for obtaining the optimal regularization parameter to give a stable numerical reconstruction of the solution. Numerical results indicate the efficiency and effectiveness of the proposed scheme. © 2012 Elsevier Ltd. All rights reserved.

Duan D.-W.,Chongqing University | Rao Y.-J.,Chongqing University | Rao Y.-J.,University of Electronic Science and Technology of China | Hou Y.-S.,Chongqing University | Zhu T.,Chongqing University
Applied Optics | Year: 2012

We demonstrate an all-fiber optical Fabry-Perot interferometer (FPI) strain sensor whose cavity is a microscopic air bubble. The bubble is formed by fusion splicing together two sections of single-mode fibers (SMFs) with cleaved flat tip and arc fusion induced hemispherical tip, respectively. The fabricated interferometers are with bubble diameters of typically ∼100 μm. Strain and temperature sensitivities of fabricated interferometers are studied experimentally; a strain sensitivity of over 4 Pm/με and a thermal sensitivity of less than 0.9 Pm/°C is obtained. © 2012 Optical Society of America.

Li J.,University of Sydney | Li J.,University of Electronic Science and Technology of China | Hu T.,University of Sydney | Jackson S.D.,University of Sydney
Optics Express | Year: 2012

A gain-switched laser transition, of a two-laser-transition cascade laser, that is driven by the adjacent laser transition which is Q-switched is demonstrated using a Ho3+-doped fluoride fiber laser. Q-switching the 5I6 ? 5I7 transition at 3.002 μm produces stable gain-switched pulses from the 5I7 → 5I8 transition at 2.074 μm; however, Q-switching the 5I7 → 5I8 transition produced multiple gain switched pulses from the 5I6 → 5I7 transition. The gain-switched pulses were measured to be of a similar duration to the Qswitched pulses suggesting that much shorter pulses of closer duration could be generated at pump power higher levels. ©2012 Optical Society of America.

Yang Y.,University of Electronic Science and Technology of China | Yang Y.,University of St. Andrews | Mazilu M.,University of St. Andrews | Dholakia K.,University of St. Andrews
Optics Letters | Year: 2012

By analysis of the far-field cross-correlation function (CCF) of partially coherent optical beams, we demonstrate an implicit rule that the number of ring dislocations (dark zones) of the far-field CCF is equal to the original topological charge of an optical vortex rendered partially coherent. This novel link between an optical vortex and its correlation singularity may offer an efficient method for measuring the orbital angular momentum of partially coherent optical vortices in fields such as astrophysics and astronomy, as well as atmospheric laser communication. © 2012 Optical Society of America.

Chen H.,Tsinghua University | Lu B.-W.,Tsinghua University | Lin Y.,University of Electronic Science and Technology of China | Feng X.,Tsinghua University
IEEE Electron Device Letters | Year: 2014

Flexible inorganic electronics with the delicate integration of stiff electronic films on soft substrate have attracted much attention recently. For the large mismatch of mechanical properties between the soft substrate and stiff electronic films in such devices, interfacial failures are always extremely dangerous. In this letter, we present theoretical analysis for the interfacial failures based on fracture mechanics and establish the criteria for the failure modes. It is found that the thin films always slip first and then transit to delamination from the substrate as the increasing of applied loading. The theoretical prediction is consistent with the experiment, which can guide the design and evaluate the reliability of flexible electronics. © 1980-2012 IEEE.

Gao X.,CAS Institute of Theoretical Physics | Gao X.,Virginia Polytechnic Institute and State University | Li T.,CAS Institute of Theoretical Physics | Li T.,University of Electronic Science and Technology of China | Shukla P.,University of Turin
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

In the lights of current BICEP2 observations accompanied with the PLANCK satellite results, it has been observed that the simple single field chaotic inflationary models provide a good agreement with their spectral index ns and large tensor-to-scalar ratio r (0.15

Yang H.-X.,Fuzhou University | Rong Z.,University of Electronic Science and Technology of China | Wang W.-X.,Beijing Normal University
New Journal of Physics | Year: 2014

The paradox of cooperation among selfish individuals still puzzles scientific communities. Although a large amount of evidence has demonstrated that the cooperator clusters in spatial games are effective in protecting the cooperators against the invasion of defectors, we continue to lack the condition for the formation of a giant cooperator cluster that ensures the prevalence of cooperation in a system. Here, we study the dynamical organization of the cooperator clusters in spatial prisoner's dilemma game to offer the condition for the dominance of cooperation, finding that a phase transition characterized by the emergence of a large spanning cooperator cluster occurs when the initial fraction of the cooperators exceeds a certain threshold. Interestingly, the phase transition belongs to different universality classes of percolation determined by the temptation to defect b. Specifically, on square lattices, 1 < b < 4/3 leads to a phase transition pertaining to the class of regular site percolation, whereas 3/2 < b < 2 gives rise to a phase transition subject to invasion percolation with trapping. Our findings offer a deeper understanding of cooperative behavior in nature and society. © 2014 IOP Publishing and Deutsche Physikalische Gesellschaft.

Xiao H.Y.,University of Electronic Science and Technology of China
Advances in Condensed Matter Physics | Year: 2013

Ab initio calculations have been performed on titanate pyrochlores A 2Ti2O7 (A = Dy, Ho, and Y) to investigate their electronic structures. The generalized gradient approximation (GGA) + U formalism has been used to correct the strong onsite Coulomb repulsion between the localized 4f electrons. The effects of effective U values on the structural and electronic properties of A2Ti2O7 (A = Dy, Ho, and Y) have been discussed. It is shown that Dy2Ti 2O7 and Ho2Ti2O7 exhibit different electronic structures from Y2Ti2O7. The strong interaction between Dy and Ho 4f electrons and O 2p orbitals may increase the covalency of 〈Dy-O〉 and 〈Ho-O〉 bonds and decrease their irradiation resistance. © 2013 H. Y. Xiao.

Xiao M.,University of Electronic Science and Technology of China
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

The d-bounded-degree vertex deletion problem, to delete at most k vertices in a given graph to make the maximum degree of the remaining graph at most d, finds applications in computational biology, social network analysis and some others. It can be regarded as a special case of the (d + 2)-hitting set problem and generates the famous vertex cover problem. The d-bounded-degree vertex deletion problem is NP-hard for each fixed d ≥ 0. In terms of parameterized complexity, the problem parameterized by k is W[2]-hard for unbounded d and fixed-parameter tractable for each fixed d ≥ 0. Previously, (randomized) parameterized algorithms for this problem with running time bound O* ((d + 1)k) are only known for d ≤ 2. In this paper, we give a uniform parameterized algorithm deterministically solving this problem in O* ((d+1)k) time for each d ≥ 3. Note that it is an open problem whether the d′-hitting set problem can be solved in O*((d′−1)k) time for d′ ≥ 3. Our result answers this challenging open problem affirmatively for a special case. Furthermore, our algorithm also gets a running time bound of O* (3.0645k) for the case that d = 2, improving the previous deterministic bound of O*(3.24k). © Springer International Publishing Switzerland 2016.

Xing L.,University of Electronic Science and Technology of China | Xing L.,University of Massachusetts Dartmouth | Amari S.V.,Parametric Technology (PTC) | Wang C.,University of Massachusetts Dartmouth
Reliability Engineering and System Safety | Year: 2012

In this paper, an efficient method is proposed for the exact reliability evaluation of k-out-of-n systems with identical components subject to phased-mission requirements and imperfect fault coverage. The system involves multiple, consecutive, and non-overlapping phases of operation, where the k values and failure time distributions of system components can change from phase to phase. The proposed method considers statistical dependencies of component states across phases as well as dynamics in system configuration and success criteria. It also considers the time-varying and phase-dependent failure distributions and associated cumulative damage effects for the system components. The proposed method is based on the total probability law, conditional probabilities and an efficient recursive formula to compute the overall mission reliability with the consideration of imperfect fault coverage. The main advantages of this method are that both its computational time and memory requirements are linear in terms of the system size, and it has no limitation on the type of time-to-failure distributions for the system components. Three examples are presented to illustrate the application and advantages of the proposed method. © 2012 Elsevier Ltd. All rights reserved.

He Q.,University of Electronic Science and Technology of China | He Q.,Lehigh University | Blum R.S.,Lehigh University
IEEE Transactions on Signal Processing | Year: 2011

For a multiple-input multiple-output (MIMO) system adopting the NeymanPearson (NP) criterion, we initially derive the diversity gain for a signal-present versus signal-absent scalar hypothesis test statistic and also for a vector signal-present versus signal-absent hypothesis testing problem. For a MIMO radar system with M transmit and N receive antennas, used to detect a target composed of Q random scatterers with possibly non-Gaussian reflection coefficients in the presence of possibly non-Gaussian clutter-plus-noise, we consider a class of test statistics, including the optimum test for Gaussian reflection coefficients and Gaussian clutter-plus-noise, and apply the previously developed results to compute the diversity gain. It is found that the diversity gain for the MIMO radar system is dependent on the cumulative distribution function (cdf) of the reflection coefficients while being invariant to the cdf of the clutter-plus-noise under some reasonable conditions requiring certain moments of the magnitude of the processed clutter-plus-noise be bounded. If the noise-free received waveforms, due to target reflection, at each receiver span a space of dimension M' ≤ M, the largest possible diversity gain is controlled by the value of min (N M', Q and the lowest order power in an expansion, about zero, of the cdf of the magnitude squared of a linear transformed version of the reflection coefficient vector. It is shown that the maximum possible diversity gain in any given scenario can be achieved without employing orthogonal waveforms. © 2006 IEEE.

Zhang Q.-M.,University of Electronic Science and Technology of China
Lecture Notes in Engineering and Computer Science | Year: 2016

Plenty of recommendation methods are put forward to alleviate the information overload problem, but no unique method can satisfy all the e-commerce web sites. One significant reason lies in the different features of data sets, for instance the sparsity of the customer-object relations which would lead to cold start problem. In this study, we obtain a data set from an online tourism website, where the purchasing behaviors are too scarce to support recommender systems well. However, there are abundant of browsing histories which are very related to customers' purchasing behaviors. We then propose a new temporal recommendation method based on the temporal browsing histories. Compared with some benchmark methods, such as collaborative filtering method, popularity- based method, and content-based method, our new method can provide very accurate and novel recommendations. It can also update the recommendation lists in real time with little computational cost. In addition, we infer that customers usually have clear targets when they enter this web site.

Li J.,University of Electronic Science and Technology of China | Xu J.,University of Sichuan
Information Sciences | Year: 2013

This paper addresses the multi-objective portfolio selection model with fuzzy random returns for investors by studying three criteria: return, risk and liquidity. In addition, securities historical data, experts' opinions and judgements and investors' different attitudes are considered in the portfolio selection process, such that the investor's individual preference is reflected by an optimistic-pessimistic parameter λ. To avoid the difficulty of evaluating a large set of efficient solutions and to ensure the selection of the best solution, a compromise approach-based genetic algorithm has been designed to solve the proposed model. In addition, a numerical example is presented to illustrate the proposed algorithm. © 2012 Elsevier Inc. All rights reserved.

Chen Y.,University of Electronic Science and Technology of China
IET Microwaves, Antennas and Propagation | Year: 2016

Dielectric resonator antennas are widely used in wireless communication systems. A theory of characteristic modes (CMs) for modal analysis of dielectric resonators is highly demanded. Although a few earlier studies had proposed CM theory for modelling scattering from dielectric bodies, the physical characteristics of these CMs and their eigenvalues are not as clear as that of those for conducting bodies. This study revisits the CM theory for dielectric resonators. Following the Poynting's theorem and the PMCHWT (Poggio, Miller, Chang, Harrington, Wu, and Tsai) equation, two generalised eigenvalue equations are formulated. The resultant eigenvalues possess clear physical meanings that are the same as those of perfectly electrically conducting problems. In addition, other possible CM formulations based on the PMCHWT equation are also discussed. Mathematical proofs are given in the Appendix to show how to formulate CM theory to physically describe the fundamental resonant modes of dielectric resonators. Numerical results are given to show the proposed CM formulations are effective in solving resonant frequencies and modal fields for dielectric resonators. © The Institution of Engineering and Technology.

Yu M.X.,University of Electronic Science and Technology of China
International Journal of Antennas and Propagation | Year: 2016

This paper investigates a novel X-band microstrip-to-microstrip vertical via transition with matching pads loaded signal via. This design has been proposed for a multilayer substrate package. The matching pads, which are located in the center of the signal via on each ground layer, are adopted to further improve the impedance matching level and thus attain better signal transition performance. A physics-based equivalent circuit modeling approach has been employed for this research. The right angle MS-to-MS via transition was also designed using this technique. The simulated S-parameters indicate that the match-pad design made a breakthrough in achieving an approximate-15 dB wide-band return loss reduction. The measured S-parameter of MS-to-MS transition showed that return loss with the matching pads is better than that without the matching pads. © 2016 M. X. Yu.

Wang Z.,Beijing University of Posts and Telecommunications | Peng Q.,University of Electronic Science and Technology of China | Milstein L.B.,University of California at San Diego
IEEE Transactions on Wireless Communications | Year: 2011

In this paper, we consider an adaptive multi-user resource allocation for the downlink transmission of a multi-cluster tactical multicarrier DS CDMA network. The goal is to maximize the sum packet throughput, subject to transmit power constraints. Since the objective function turns out to be noncovex and nondifferentiable, we propose a simple iterative bisection algorithm. At each iteration, a closed-form expression is derived for the transmit power, subchannel, and modulation assignment, which significantly reduces the computational complexity. We also provide an optimization algorithm for the downlink transmission under the condition of imperfect channel knowledge, and investigate the effects of both channel estimation error and partial-band jamming. © 2006 IEEE.

Qin Y.,KTH Royal Institute of Technology | Qin Y.,CAS Institute of Remote Sensing | Li S.,University of Electronic Science and Technology of China | Vu T.-T.,University of Nottingham Malaysia Campus | And 2 more authors.
Optics Express | Year: 2015

Urban land cover map is essential for urban planning, environmental studies and management. This paper aims to demonstrate the potential of geometric and radiometric features derived from LiDAR waveform and point cloud data in urban land cover mapping with both parametric and non-parametric classification algorithms. Small footprint LiDAR waveform data acquired by RIEGL LMS-Q560 in Zhangye city, China is used in this study. A LiDAR processing chain is applied to perform waveform decomposition, range determination and radiometric characterization. With the synergic utilization of geometric and radiometric features derived from LiDAR data, urban land cover classification is then conducted using the Maximum Likelihood Classification (MLC), Support Vector Machines (SVM) and random forest algorithms. The results suggest that the random forest classifier achieved the most accurate result with overall classification accuracy of 91.82% and the kappa coefficient of 0.88. The overall accuracies of MLC and SVM are 84.02, and 88.48, respectively. The study suggest that the synergic utilization of geometric and radiometric features derived from LiDAR data can be efficiently used for urban land cover mapping, the non-parametric random forest classifier is a promising approach for the various features with different physical meanings. © 2015 Optical Society of America.

Xiao-Feng P.,University of Electronic Science and Technology of China | Xiao-Feng P.,CAS Shenyang International Center for Materials Physics
Progress in Biophysics and Molecular Biology | Year: 2012

A new theory of bio-energy transport along protein molecules in living systems, where the energy is released by hydrolysis of adenosine triphosphate (ATP), is proposed based on some physical and biological reasons. In the new theory, the Davydov's Hamiltonian and wave function of the systems are simultaneously modified and extended. A new interaction has been added into Davydov's Hamiltonian. The wave function of the excitation state of single particles for the excitons in the Davydov model is replaced by a new wave function of two-quanta quasicoherent state. In such a case, the bio-energy is transported by the new soliton, which differs from the Davydov's soliton. The soliton is formed through self- trapping of two excitons interacting amino acid residues. The exciton is generated by vibrations of amide-I (CO stretching) arising from the energy of hydrolysis of ATP. The properties of the new soliton are extensively studied by analytical method and its lifetime is calculated using the nonlinear quantum perturbation theory and a wide ranges of parameter values relevant to protein molecules. The lifetime of the new soliton at the biological temperature 300K is enough large and belongs to the order of 10-10s, or τ/τ0≥700, in which the soliton can transports over several hundreds amino acid residues. These studied results show clearly that the new soliton is thermally stable and has so larger lifetime that it can play an important role in biological processes. Thus the new model is a candidate of the bio-energy transport mechanism in protein molecules. In the meanwhile, the influences of structure nonuniformity in protein molecules and temperature of the systems on the states and properties of the soliton transport of bio-energy are numerically simulated and studied by the fourth-order Runge-Kutta method. The structure nonuniformity arises from the disorder distributions of masses of amino acid residues, side groups and impurities, which results also in the fluctuations of the spring constant of protein molecules, dipole-dipole interaction between the neighboring amides, exciton-phonon (vibration of amino acids)interaction, chain-chain interaction among the three channels and ground state energy of the systems. We investigated the behaviors and states of the new solitons in a single protein molecular chain and α-Helix protein molecules with three channels under influences of the structure nonuniformity. We prove first that the bio-energy is transported by a soliton, which can move without dispersion, retaining its shape, velocity and energy in a uniform and periodic protein molecule. When the structure nonuniformity exists, although the fluctuations of the spring constant, dipole-dipole interaction constant, exciton-phonon coupling constant and ground state energy and the nonuniformity distributions of masses of amino acid residues can change the states and properties of motion of new soliton, they are still quite stable and very robust against these structure nonuniformities, i.e., even there are a larger structure nonuniformity in the protein molecules, the new solitons cannot be still dispersed. If the effects of thermal perturbation of medium on the soliton in nonuniform proteins is considered again, the new soliton can transport also over a larger spacing of 400 amino acids and has a longer time period of 300ps, it is still thermally stable up to 320K under the influence of the above structure nonuniformities. However, the new soliton disperses in the case of a higher temperature of 325K and in more large structure nonuniformity. Thus, we determine that the new soliton's lifetime and critical temperature are 300ps and 320K, respectively. These results are also consistent with analytical data obtained via quantum perturbed theory. For α-Helix protein molecules with three channels, the results obtained show that the structure nonuniformity and quantum fluctuation can change the states and features of the new solitons, for example, the amplitudes, energies and velocities of the new soliton are decreased, but the solitons have been not destroyed, they can still transport steadily along the molecular chains retaining energy and momentum. When the quantum fluctuations are larger, such as, structure disorders and quantum fluctuations of 0.67<αK<2, ΔW=±8%W-, ΔJ=±1%J-, Δ(χ1+χ2)=±3%(χ-1+χ-2) and ΔL=±1%L- and Δe{open}0=e{open}|βn|, e{open}=0.1meV, |βn|<0.5, the new soliton is still stable. Therefore, the new solitons are quite robust against these nonuniform effects. However, they will be dispersed or disrupted in cases of very large structure nonuniformity. When the influence of temperature on solitons is considered, we find that the new solitons can transport steadily over 333 amino acid residues in the case of a long time period of 120ps, in which the soliton can retain its shape and energy to travel forward along protein molecules after their mutual collision at the biological temperature of 300K. However, the soliton disperses in cases of higher temperatures 325K under action of a larger structure disorder. Thus, its critical temperature is about 320K. When the effects of structure nonuniformity andtemperature are considered simultaneously, then the new soliton has still high thermal stability andcan transport also along the protein molecular chains retaining its amplitude, energy and velocity, they will disperses in the larger fluctuations, for example, 0.67M-

Levitin G.,University of Electronic Science and Technology of China | Xing L.,University of Massachusetts Dartmouth
Reliability Engineering and System Safety | Year: 2010

The paper presents an algorithm for evaluating performance distribution of complex series-parallel multi-state systems with common cause failures caused by propagation of failures in system elements. The failure propagation can have a selective effect, which means that the failures originated from different elements can cause failures of different subsets of system elements. The suggested algorithm is based on the universal generating function approach and a generalized reliability block diagram method (recursive aggregation of pairs of elements and their replacement by an equivalent one). The performance distribution evaluation procedure is repeated for each combination of common cause failures. Illustrative examples are provided. © 2010 Elsevier Ltd. All rights reserved.

Xiao F.,University of Electronic Science and Technology of China
Asia-Pacific Microwave Conference Proceedings, APMC | Year: 2011

A simple and fast coupling matrix synthesis technique to directly synthesize generalized bandpass filters of arbitrary bandwidth is briefly discussed in this paper. Unlike those well-known coupling matrix synthesis techniques for generalized Chebyshev filtering function that are only accurate for narrowband filters, the technique is this paper can be used to synthesize filters of arbitrary bandwidth with arbitrarily placed transmission zeros. Compared with other synthesis techniques of wideband filters, the technique in this paper is much simpler and faster. © 2011 Engineers Australia.

Li Y.,University of Electronic Science and Technology of China
Ruan Jian Xue Bao/Journal of Software | Year: 2012

The termination of linear loops has been studied extensively, but there are few results collected on termination of nonlinear loops. Through the fixed point theorem, this paper presents an approach to the decision of termination of a class of nonlinear loops. In addition, for a particular class of loops, the paper gives a condition under which the termination of the loops is decidable. © 2012 ISCAS.

Cermak T.,University of Minnesota | Baltes N.J.,University of Minnesota | Cegan R.,Academy of Sciences of the Czech Republic | Zhang Y.,University of Electronic Science and Technology of China | Voytas D.F.,University of Minnesota
Genome Biology | Year: 2015

Background: The use of homologous recombination to precisely modify plant genomes has been challenging, due to the lack of efficient methods for delivering DNA repair templates to plant cells. Even with the advent of sequence-specific nucleases, which stimulate homologous recombination at predefined genomic sites by creating targeted DNA double-strand breaks, there are only a handful of studies that report precise editing of endogenous genes in crop plants. More efficient methods are needed to modify plant genomes through homologous recombination, ideally without randomly integrating foreign DNA. Results: Here, we use geminivirus replicons to create heritable modifications to the tomato genome at frequencies tenfold higher than traditional methods of DNA delivery (i.e., Agrobacterium). A strong promoter was inserted upstream of a gene controlling anthocyanin biosynthesis, resulting in overexpression and ectopic accumulation of pigments in tomato tissues. More than two-thirds of the insertions were precise, and had no unanticipated sequence modifications. Both TALENs and CRISPR/Cas9 achieved gene targeting at similar efficiencies. Further, the targeted modification was transmitted to progeny in a Mendelian fashion. Even though donor molecules were replicated in the vectors, no evidence was found of persistent extra-chromosomal replicons or off-target integration of T-DNA or replicon sequences. Conclusions: High-frequency, precise modification of the tomato genome was achieved using geminivirus replicons, suggesting that these vectors can overcome the efficiency barrier that has made gene targeting in plants challenging. This work provides a foundation for efficient genome editing of crop genomes without the random integration of foreign DNA. © 2015 Čermák et al.

Yang Y.,University of Electronic Science and Technology of China | Dong Y.,Soochow University of China | Zhao C.,Soochow University of China | Cai Y.,Soochow University of China
Optics Letters | Year: 2013

A theoretical model is proposed to describe a novel vortex beam named anomalous vortex (AV) beam. Analytical propagation formula for the proposed beam passing through a paraxial ABCD optical system is derived, and the propagation properties of such beam in free space are studied numerically. It is interesting to find that an AV beam will eventually become an elegant Laguerre-Gaussian beam in the far field (or in the focal plane) in free space. Furthermore, we report experimental generation of an AV beam and measure its propagation properties. Our experimental results are consistent with the theoretical predictions. © 2013 Optical Society of America.

Ge S.S.,University of Electronic Science and Technology of China | Ge S.S.,Interactive Digital Media Institute | Li Z.,South China University of Technology
IEEE Transactions on Automatic Control | Year: 2014

In this technical note, high dimensional integral Lyapunov functions are introduced for a class of MIMO nonlinear systems with unknown nonlinearities. First, adaptive state feedback control is presented based on the integral Lyapunov function. When only the output is measurable, by using a high-gain observer to estimate the derivative of the system output, adaptive output feedback control is also derived. The proposed control scheme provides a general approach to stabilize the MIMO plant without any restrictive assumptions. The control is continuous and ensures closed-loop stability and convergence of the tracking error to a small residual set. The size of the tracking error at steady state can be specified a priori and guaranteed by choosing the design parameters. © 1963-2012 IEEE.

Dong B.,Zhejiang University | Ni D.,University of Electronic Science and Technology of China | Wang Y.,University of Windsor
Environmental and Resource Economics | Year: 2012

A polluted river network is populated with agents (e. g., firms, villages, municipalities, or countries) located upstream and downstream. This river network must be cleaned, the costs of which must be shared among the agents. We model this problem as a cost sharing problem on a tree network. Based on the two theories in international disputes, namely the Absolute Territorial Sovereignty (ATS) and the Unlimited Territorial Integrity (UTI), we propose three different cost sharing methods for the problem. They are the Local Responsibility Sharing (LRS), the Upstream Equal Sharing (UES), and the Downstream Equal Sharing (DES), respectively. The LRS and the UES generalize Ni and Wang (Games Econ Behav 60:176-186, 2007) but the DES is new. The DES is based on a new interpretation of the UTI. We provide axiomatic characterizations for the three methods. We also show that they coincide with the Shapley values of the three different games that can be defined for the problem. Moreover, we show that they are in the cores of the three games, respectively. Our methods can shed light on pollution abatement of a river network with multiple sovereignties. © 2012 Springer Science+Business Media B.V.

Li Y.,National University of Singapore | Ge S.S.,National University of Singapore | Ge S.S.,University of Electronic Science and Technology of China
IEEE/ASME Transactions on Mechatronics | Year: 2014

In this paper, adaptive impedance control is proposed for a robot collaborating with a human partner, in the presence of unknown motion intention of the human partner and unknown robot dynamics. Human motion intention is defined as the desired trajectory in the limb model of the human partner, which is extremely difficult to obtain considering the nonlinear and time-varying property of the limb model. Neural networks are employed to cope with this problem, based on which an online estimation method is developed. The estimated motion intention is integrated into the developed adaptive impedance control, which makes the robot follow a given target impedance model. Under the proposed method, the robot is able to actively collaborate with its human partner, which is verified through experiment studies. © 1996-2012 IEEE.

Yang H.,University of Electronic Science and Technology of China
International journal of nanomedicine | Year: 2011

Multifunctionalized nanoparticles (NPs) are emerging as ideal tools for gene/drug delivery, bioimaging, labeling, or intracellular tracking in biomedical applications, and have attracted considerable attention owing to their unique advantages. In this study, fluorescent silica NPs were synthesized by a modified Stöber method using conjugates of 3-mercaptopropyltrimethoxysilane (MPS) and maleimide-fluorescein isothiocyanate (maleimide-FITC). Mean diameters of the NPs were controlled between 212-2111 nm by regulating MPS concentration in the reaction mixture. Maleimide-FITC molecules were doped into NPs or conjugated to the surface of NPs through the chemical reaction of maleimide and thiol groups. The data showed that the former NPs are better than the latter by comparing their fluorescence intensity. Furthermore, folate molecules were linked to the FITC-doped silica NPs by using polyethylene glycol (PEG) (NH2-PEG-maleimide) as a spacer, thus forming folate receptor targeting fluorescent NPs, referred to as NPs(FITC)-PEG-Folate. The quantitative analysis of cellular internalization into different cancer cells showed that the delivery efficiency of KB cells (folate receptor-positive cells) is more than six-fold higher than that of A549 cells (folate receptor-negative cells). The delivery efficiency of KB cells decreased significantly after free folate addition to the cell culture medium because the folate receptors were occupied by the free folate. The NPs endocytosis mechanism was also investigated. It was shown that clathrin, an inhibitor of cell phagocytosis, markedly decreased the NPs uptake into KB cells, suggesting that it plays an important role in NPs cellular internalization. These results demonstrated that the novel particles of NPs(FITC)-PEG-Folate are promising for fluorescent imaging or targeting delivery to folate receptor-positive tumors.

Wang W.-Q.,University of Electronic Science and Technology of China
The Scientific World Journal | Year: 2013

It is well recognized that a wind turbine has a large radar cross-section (RCS) and, due to the movement of the blades, the wind turbine will generate a Doppler frequency shift. This scattering behavior may cause severe interferences on existing radar systems including static ground-based radars and spaceborne or airborne radars. To resolve this problem, efficient techniques or algorithms should be developed to mitigate the effects of wind farms on radars. Herein, one transponder-based mitigation technique is presented. The transponder is not a new concept, which has been proposed for calibrating high-resolution imaging radars. It modulates the radar signal in a manner that the retransmitted signals can be separated from the scene echoes. As wind farms often occupy only a small area, mitigation processing in the whole radar operation will be redundant and cost inefficient. Hence, this paper uses a transponder to determine whether the radar is impacted by the wind farms. If so, the effects of wind farms are then mitigated with subsequent Kalman filtering or plot target extraction algorithms. Taking airborne synthetic aperture radar (SAR) and pulse Doppler radar as the examples, this paper provides the corresponding system configuration and processing algorithms. The effectiveness of the mitigation technique is validated by numerical simulation results. © 2013 Wen-Qin Wang.

Li C.,Zhejiang University | Zheng Q.,University of Electronic Science and Technology of China
Physical Biology | Year: 2010

As is well known, synchronization phenomena are ubiquitous in neuronal systems. Recently a lot of work concerning the synchronization of the neuronal network has been accomplished. In these works, the synapses are usually considered reliable, but experimental results show that, in biological neuronal networks, synapses are usually unreliable. In our previous work, we have studied the synchronization of the neuronal network with unreliable synapses; however, we have not paid attention to the effect of topology on the synchronization of the neuronal network. Several recent studies have found that biological neuronal networks have typical properties of small-world networks, characterized by a short path length and high clustering coefficient. In this work, mainly based on the small-world neuronal network (SWNN) with inhibitory neurons, we study the effect of network topology on the synchronization of the neuronal network with unreliable synapses. Together with the network topology, the effects of the GABAergic reversal potential, time delay and noise are also considered. Interestingly, we found a counter-intuitive phenomenon for the SWNN with specific shortcut adding probability, that is, the less reliable the synapses, the better the synchronization performance of the SWNN. We also consider the effects of both local noise and global noise in this work. It is shown that these two different types of noise have distinct effects on the synchronization: one is negative and the other is positive. © 2010 IOP Publishing Ltd.

Chen W.,North University of China | Lin H.,University of Electronic Science and Technology of China
Biochemical and Biophysical Research Communications | Year: 2010

In the process of cell division, a great deal of proteins is assembled into three distinct organelles, namely midbody, centrosome and kinetochore. Knowing the localization of microkit (midbody, centrosome and kinetochore) proteins will facilitate drug target discovery and provide novel insights into understanding their functions. In this study, a support vector machine (SVM) model, MicekiPred, was presented to predict the localization of microkit proteins based on gene ontology (GO) information. A total accuracy of 77.51% was achieved using the jackknife cross-validation. This result shows that the model will be an effective complementary tool for future experimental study. The prediction model and dataset used in this article can be freely downloaded from http://cobi.uestc.edu.cn/people/hlin/tools/MicekiPred/. © 2010 Elsevier Inc.

Li X.D.,Nanyang Technological University | Chen T.P.,Nanyang Technological University | Liu P.,Nanyang Technological University | Liu Y.,University of Electronic Science and Technology of China | Leong K.C.,Globalfoundries
Optics Express | Year: 2013

Band gaps and exciton binding energies of undoped and Aldoped ZnO thin films were determined from optical absorption measurement based on the Elliott's exciton absorption theory. As compared to the undoped films, the doped films exhibit a band gap expansion and a reduction in the exciton binding energies due to the free electron screening effect, which suppresses the excitonic absorption and results in a blue shift of the absorption edge. The undoped and doped films show the same quantum size dependence, i.e. both the exciton binding energies and band gap energies increase with decreasing grain size of the oxides. © 2013 Optical Society of America.

Wang H.,Rutgers University | Zou Q.,Rutgers University | Xu H.,University of Electronic Science and Technology of China
Automatica | Year: 2012

In this article, the problem of nonperiodic tracking-transition switching with preview is considered. Such a control problem exists in applications including nanoscale material property mapping, robot manipulation, and probe-based nanofabrication, where the output needs to track the desired trajectory during the tracking sections, and rapidly transit to another point during the transition sections with no post-transition oscillations. Due to the coupling between the control of the tracking sections and that of the transition ones, and the potential mismatch of the boundary system state at the tracking-transition switching instants, these control objectives become challenging for nonminimum-phase systems. In the proposed approach, the optimal desired output trajectory for the transition sections is designed through a direct minimization of the output energy, and the needed control input that maintains the smoothness of both the output and the system state across all tracking-transition switching is obtained through a preview-based stable-inversion approach. The needed preview time is quantified by the characteristics of the system dynamics, and can be minimized via the recently developed optimal preview-based inversion technique. The proposed approach is illustrated through a nanomanipulation example in simulation. © 2012 Elsevier Ltd. All rights reserved. © 2012 Elsevier Ltd. All rights reserved.

Li X.,University of Electronic Science and Technology of China
Mathematical Methods in the Applied Sciences | Year: 2015

This paper is devoted to the attraction-repulsion chemotaxis system with nonlinear diffusion: ut=∇·(D(u)∇u)-χ∇·(u∇v)+ζ∇·(u∇w)+uf(u),x∈Ω,t>0,vt=Δv-α1v+β1u,x∈Ω,t>0,wt=Δw-α2w+β2u,x∈Ω,t>0, where χ > 0, ζ > 0, αi>0, βi>0 (i = 1,2) and f(s)≤κ - μsτ. In two-space dimension, we prove the global existence and uniform boundedness of the classical solution to this model for any μ > 0. © 2015 John Wiley & Sons, Ltd.

Chen X.,University of Electronic Science and Technology of China | Shen Z.-J.,University of California at Berkeley
IIE Transactions (Institute of Industrial Engineers) | Year: 2012

This article studies a one-period two-party supply chain with a service requirement. At the beginning of a single retail season, the retailer can obtain goods by either ordering from a firm or by purchasing and exercising call options. The retailers optimal ordering policy and the suppliers optimal production policy are derived in the presence of options contracts and a service requirement. In addition, it is shown that options contracts benefit both the retailer and supplier. Furthermore, it is shown that the retailers optimal expected profit is non-increasing in the service requirement and the suppliers optimal expected profit is non-decreasing in the service requirement, either with or without options contracts. A special class of distribution-free contracts that can coordinate the supply chain with options contracts and the service requirement are derived. Furthermore, as opposed to the case of non-coordinating contracts, it is shown that there is always a Pareto contract. Finally, the retailers and supply chains optimal service level are derived. © 2012 Copyright Taylor and Francis Group, LLC.

Lei D.,University of Electronic Science and Technology of China | Li J.,Huazhong University of Science and Technology | Liu Z.,Huazhong University of Science and Technology
International Journal of Production Economics | Year: 2012

We study the risk management strategies in supplier chain when the disruptions of demand and cost are the private information. We use linear contract menus to analyze the supply chain under demand and cost disruptions with asymmetric information. We derive out the optimal contract for the supplier and show the impact of asymmetric disruption information on the performance of the supplier, the retailer and the supply chain. Further, we find out that the effects of demand and cost disruption may interact with each other while the production plan does not change in some cases. The optimal production quantity with asymmetric information is not greater than that with symmetric information. The information value for all members is not monotone in all parameters. Each change will induce that the supplier revises his strategy when the supply chain members trade off the cost of deviation and asymmetric information. © 2010 Elsevier B.V. All rights reserved.

Duan B.,Xidian University | Yang Y.,Xidian University | Zhang B.,University of Electronic Science and Technology of China
Solid-State Electronics | Year: 2010

A novel concept of REBULF (REduced BULk Field) is proposed for the developing smart power integrated circuit with the thin epitaxy layer. The REBULF LDMOS structure is designed with N+ buried layer embedded in the high-resistance substrate. The mechanism of breakdown of the new device is that the high electric field around the drain is reduced by N+ buried layer, which causes the redistribution of the bulk electric field in the drift region of the REBULF LDMOS so that the substrate supports more biases. The critical condition of the REBULF technology is analyzed and validated by 2-D MEDICI simulation results, which is the product of the location of N+ buried layer and substrate's doping is not more than 1 × 1012 cm -2. The breakdown voltage of REBULF LDMOS is increased by 75% in comparison to the conventional RESURF LDMOS from the simulation results. The experimental results show the high electric field around the drain is reduced as the depletion region spreads to N+ buried layer. Although the leakage has increased a little, this increase is not enough to cause the avalanche breakdown. Crown Copyright © 2010 Published by Elsevier Ltd. All rights reserved.

Wang W.-Q.,University of Electronic Science and Technology of China
Fluctuation and Noise Letters | Year: 2011

Global positioning system (GPS)-disciplined quartz oscillator can provide a precise time and frequency standard. However, possible phase errors and biases caused by oscillator phase noise must be suppressed or compensated for some applications, e.g., distributed radar systems, in which a rigorous phase or frequency synchronization precision is required. Moreover, the quartz oscillator is necessary to provide a holdover of time or frequency when the GPS signals are lost. This letter presents a signal processing and hardware design strategy for suppressing phase noise in GPS-disciplined frequency synchronization systems. Firstly, the quartz oscillator frequency is disciplined by the GPS pulse-per-second (PPS) signals. Next, a recursive algorithm is applied to suppress the possible jitters when the GPS PPS signals are lost. Finally, a direct digital synthesizer (DDS)-based multiple frequency tuning synthesizer is presented to generate the whole system frequencies. Although the use of GPS signal to discipline oscillator for frequency transfer is not a new concept, the originality of this letter lies in the proposed phase noise suppression methods, along with the hardware design strategies. © 2011 World Scientific Publishing Company.

Xiao F.,University of Electronic Science and Technology of China
International Journal of Circuit Theory and Applications | Year: 2015

Summary: Conventional synthesis techniques for general Chebyshev lowpass, highpass, and bandstop filters are usually based on general Chebyshev filtering function, from which lowpass prototype is set up. By applying the lowpass to lowpass, highpass, or bandstop frequency transformation on realization networks of lowpass prototypes, final realization networks of general Chebyshev lowpass, highpass, and bandstop filters are obtained. In this paper, direct synthesis techniques for general Chebyshev lowpass, highpass, and bandstop filters are discussed. Transmission zeros can be placed wherever they are desired to control the performance of the filters. Unlike conventional synthesis techniques, they derive filtering polynomials constituting network parameters directly in the lowpass, highpass, or bandstop domain, which might find applications in analogue and digital filter design. Several examples are presented for demonstration. © 2015 John Wiley & Sons, Ltd.

Yang H.,University of Electronic Science and Technology of China
International journal of nanomedicine | Year: 2011

The expression of certain endothelial cell adhesion molecules is increased during endothelial dysfunction or inflammatory activation. This has led to the concept of using microbubbles for targeted molecular imaging or drug delivery. In this approach, microbubbles with a specific ligand to receptors expressed at the site of specific diseases are constructed. The present study aimed to engineer a novel type of bio-functionalized microbubbles (vascular cell adhesion molecule 1 [VCAM-1]-targeted microbubbles), and determine whether VCAM-1-targeted microbubbles exhibit specific adhesion to lipopolysaccharide (LPS)-activated endothelial cells. Our data showed that VCAM-1 expression was significantly upregulated in both LPS-activated endothelial cells in vitro and endothelium in a rat atherosclerosis model in vivo. Targeted microbubbles were designed by conjugating anti-VCAM-1 monoclonal antibodies to the shell of microbubbles using biotin-avidin bridging chemistry methods. Microbubble adhesion to endothelial cells was assessed in a flow chamber at two shear stress conditions (6.3 and 10.4 dynes/cm 2). Our data showed that microbubble adhesion depends on both the surface anti-VCAM-1 antibody densities and the exposed shear stresses. Adhesion of VCAM-1-targeted microbubbles onto LPS-activated endothelial cells increased with the surface antibody densities, and decreased with the exposed shear stresses. These findings showed that the specific ligand-carrying microbubbles have considerable potential in targeted ultrasound molecular imaging or ultrasound-assisted drug/gene delivery applications.

Wu S.-C.,University of Electronic Science and Technology of China | Wang D.,Princeton UT | Chen Y.-M.,National Taiwan University
International Journal of Thermal Sciences | Year: 2014

This study investigated the effect of double-layer wick thickness ratio on the heat transfer performance of loop heat pipe (LHP). With the outer layer of the wick being biporous to allow vapor to travel and the inner layer being monoporous to provide capillary force, the wick used in this study eliminated the problems with wick's structural strength and difficulty in vapor release encountered when using a monoporous wick. By changing the double-layer wick thickness ratio, the LHP heat transfer performance was enhanced. Under a fixed total wick thickness, the double-layer wick thickness ratio was varied by adjusting the biporous and monoporous layers' thicknesses; higher thickness ratio corresponds to the wick having more biporous wick characteristics, and lower thickness ratio corresponds to the wick being more like a monoporous wick. In this study, the ratios investigated were 0.28, 0.42, 0.57, 0.71, 0.86, and 1. Results showed that at 0.57, the highest heat load under 85 °C was 1060 W, the total thermal resistance was 0.065 °C/W, the heat flux was 50 W/cm2, the heat transfer coefficient was 188 kW/m2 °C, and the porosity was 82%. Compared with the double-layer wick performance reported thus far, performance was increased by about 50%, and compared with that of the monoporous wick, the performance increase was about 200%. The best thickness ratio was successfully determined, and the critical heat load reached, for the first time, the order of kW. A trend line and empirical equation for LHP performance results for monoporous (thickness ratio 0) [1], double-layer (thickness ratio 0.28 ∼ 0.86), and biporous (thickness ratio 1) wicks were fitted and established, providing a reference for future designs. © 2014 Elsevier Masson SAS. All rights reserved.

Yu Y.,University of Electronic Science and Technology of China | Wang J.,Union College at Schenectady
IEEE Transactions on Image Processing | Year: 2010

Ultrasound B-scan exhibits shadowing and enhancement artifacts due to acoustic wave propagation and spatially varying scatter attenuation across layers of tissues. These artifacts hide underlying echo signals that are truly clinically indicative of diseases. Attenuation compensation estimates and corrects for shadowing and enhancement artifacts, which improves the quality of ultrasound imaging. Block-based attenuation compensation methods, widely employed in commercial scanners, produce results with resolutions limited by the block size. To obtain higher spatial resolution (as desired for quantitative analysis), we present a backscatter-contour-attenuation (BCA) joint estimation model for attenuation compensation in pulse-echo imaging using a set of self-consistent partial differential equations and a contour evolution model. The problem is posed as reconstructing sources of information from observations. We derive the joint estimation model from minimizing a cost functional of separated attributes with region-based isotropic regularizations. A three-step alternating minimization method is adopted towards a tractable numerical solution. Detailed numerical methods are described. The efficacy of the proposed approach is demonstrated using simulated and real images. © 2010 IEEE.

Li Y.,University of Electronic Science and Technology of China
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2011

The identification of constituent components of each sign gesture is a practical way of establishing large-vocabulary sign language recognition (SLR) system. Aiming at developing such a system using portable accelerometer (ACC) and surface electromyographic (sEMG) sensors, this work proposes a method for automatic SLR at the component level. The preliminary experimental results demonstrate the effectiveness of the proposed method and the feasibility of interpreting sign components from ACC and sEMG data. Our study improves the performance of SLR based on ACC and sEMG sensors and will promote the realization of a large-vocabulary portable SLR system.

Kong L.,University of Electronic Science and Technology of China
Proceedings of 2011 IEEE CIE International Conference on Radar, RADAR 2011 | Year: 2011

Via the reiterative Maximum Signal Minus Interference Level (MSMIL) criterion and adaptive beamforming, a novel algorithm is proposed to suppress both the mutual interference and strong direct-path interference for shared-spectrum multistatic radar. Numerical results show advantages of the proposed method. © 2011 IEEE.

Wang Z.,University of Electronic Science and Technology of China | Su Q.,Hunan University | Deng H.,Hunan University
Physical Chemistry Chemical Physics | Year: 2013

Using first principles calculations based on density functional theory, the adsorption and diffusion properties of Li and Mg atoms on single-layered and bulk V2O5 are investigated. The simulation results show that the diffusion barrier of Li on the single-layered V2O 5 is decreased compared with that of the bulk V2O 5, which indicates that the Li mobility can be significantly enhanced on the single-layered V2O5. The increased binding energies of Li to single-layered V2O5 make them more attractive for promising cathode materials. Although the diffusion barrier of Mg on the single-layered V2O5 does not decrease, the binding energies of Mg to single-layered V2O5 is increased compared with that of bulk V2O5, thus the single-layered V2O5 is an attractive cathode material for rechargeable ion batteries. © 2013 The Owner Societies.

Li Y.,Institute for Infocomm Research | Ge S.S.,National University of Singapore | Ge S.S.,University of Electronic Science and Technology of China
IEEE Transactions on Control Systems Technology | Year: 2014

In this paper, impedance learning is investigated for robots interacting with unknown environments. A two-loop control framework is employed and adaptive control is developed for the inner-loop position control. The environments are described as time-varying systems with unknown parameters in the state-space form. The gradient-following and betterment schemes are employed to obtain a desired impedance model, subject to unknown environments. The desired interaction performance is achieved in the sense that a defined cost function is minimized. Simulation and experiment studies are carried out to verify the validity of the proposed method. © 2013 IEEE.

Pang X.-F.,University of Electronic Science and Technology of China | Pang X.-F.,CAS Shenyang International Center for Materials Physics
Physics of Life Reviews | Year: 2011

The bio-energy transport is a basic problem in life science and related to many biological processes. Therefore to establish the mechanism of bio-energy transport and its theory have an important significance. Based on different properties of structure of α-helical protein molecules some theories of bio-energy transport along the molecular chains have been proposed and established, where the energy is released by hydrolysis of adenosine triphosphate (ATP). A brief survey of past researches on different models and theories of bio-energy, including Davydov's, Takeno's, Yomosa's, Brown et al.'s, Schweitzer's, Cruzeiro-Hansson's, Forner's and Pang's models were first stated in this paper. Subsequently we studied and reviewed mainly and systematically the properties, thermal stability and lifetimes of the carriers (solitons) transporting the bio-energy at physiological temperature 300 K in Pang's and Davydov's theories. From these investigations we know that the carrier (soliton) of bio-energy transport in the α-helical protein molecules in Pang's model has a higher binding energy, higher thermal stability and larger lifetime at 300 K relative to those of Davydov's model, in which the lifetime of the new soliton at 300 K is enough large and belongs to the order of 10-10 s or τ/τ0≥700. Thus we can conclude that the soliton in Pang's model is exactly the carrier of the bio-energy transport, Pang's theory is appropriate to α-helical protein molecules. © 2011 Elsevier B.V.

Guo F.B.,University of Electronic Science and Technology of China
Genetics and molecular research : GMR | Year: 2012

Horizontal gene transfer is an important mechanism for the evolution of microbial genomes, and many horizontal gene transfer events are facilitated by genomic islands (GIs). Until now, few reports have provided evidence for the co-evolution of horizontally transferred genes and their hosts. We obtained 17 groups of homologous GIs, all of which appear in 8 or more bacterial strains of the same species or genus. Using phylogenetic analyses, we found that the topological structure of a distance tree based on the proteins of each group of homologous GIs was consistent with that based on the complete proteomes of the hosts. This result clearly indicates that GIs and their bacterial hosts have co-evolved. In addition to presenting and providing evidence for a novel concept, i.e., the co-evolution of GIs and their bacterial hosts, we also describe a new and interesting detail for the phylogenetic analysis of horizontally transferred genes: consistent phylogenetic trees can be obtained by focusing on homologous GIs despite the commonly accepted theory that the phylogenies of horizontally transferred sequences and host organisms should be inconsistent.

Zhou W.,University of Electronic Science and Technology of China | Zurada J.M.,University of Louisville
Neural Computation | Year: 2010

This letter discusses the competitive layer model (CLM) for a class of discrete-time recurrent neural networks with linear threshold (LT) neurons. It first addresses the boundedness, global attractivity, and complete stability of the networks. Two theorems are then presented for the networks to have CLM property. We also present the analysis for network dynamics, which performs a column winner-take-all behavior and grouping selection among different layers. Furthermore, we propose a novel synchronous CLM iteration method, which has similar performance and storage allocation but faster convergence compared with the previous asynchronous CLM iteration method (Wersing, Steil, & Ritter, 2001). Examples and simulation results are used to illustrate the developed theory, the comparison between two CLM iteration methods, and the application in image segmentation.

Li H.,University of Electronic Science and Technology of China | Ngan K.N.,Chinese University of Hong Kong
IEEE Transactions on Image Processing | Year: 2011

In this paper, we introduce a method to detect co-saliency from an image pair that may have some objects in common. The co-saliency is modeled as a linear combination of the single-image saliency map (SISM) and the multi-image saliency map (MISM). The first term is designed to describe the local attention, which is computed by using three saliency detection techniques available in literature. To compute the MISM, a co-multilayer graph is constructed by dividing the image pair into a spatial pyramid representation. Each node in the graph is described by two types of visual descriptors, which are extracted from a representation of some aspects of local appearance, e.g., color and texture properties. In order to evaluate the similarity between two nodes, we employ a normalized single-pair SimRank algorithm to compute the similarity score. Experimental evaluation on a number of image pairs demonstrates the good performance of the proposed method on the co-saliency detection task. © 2006 IEEE.

Lin H.,University of Electronic Science and Technology of China
Journal of biomolecular structure & dynamics | Year: 2012

Knowledge of protein structural class can provide important information about its folding patterns. Many approaches have been developed for the prediction of protein structural classes. However, the information used by these approaches is primarily based on amino acid sequences. In this study, a novel method is presented to predict protein structural classes by use of chemical shift (CS) information derived from nuclear magnetic resonance spectra. Firstly, 399 non-homologue (about 15% identity) proteins were constructed to investigate the distribution of averaged CS values of six nuclei ((13)CO, (13)Cα, (13)Cβ, (1)HN, (1)Hα and (15)N) in three protein structural classes. Subsequently, support vector machine was proposed to predict three protein structural classes by using averaged CS information of six nuclei. Overall accuracy of jackknife cross-validation achieves 87.0%. Finally, the feature selection technique is applied to exclude redundant information and find out an optimized feature set. Results show that the overall accuracy increased to 88.0% by using the averaged CSs of (13)CO, (1)Hα and (15)N. The proposed approach outperformed other state-of-the-art methods in terms of predictive accuracy in particular for low-similarity protein data. We expect that our proposed approach will be an excellent alternative to traditional methods for protein structural class prediction.

Dai G.L.,Zhejiang University | Xia M.Y.,University of Electronic Science and Technology of China
Journal of Electromagnetic Waves and Applications | Year: 2011

In this paper, we present a novel scheme of unequal Wilkinson power divider operating at two arbitrary frequencies. The proposed power divider consists of two isolation resistors, two output matching transformers and two cascading asymmetric coupled-lines, which are used to achieve unequal power division. To investigate the proposed asymmetric coupled structure, in- and anti-phase (c/π-mode) analysis is adopted, instead of conventional even/odd-mode analysis. And analytical design equations are derived based on the transmission line theory. It is found that both frequency ratio and power dividing ratio can be adjusted, respectively. As a typical example, an experimental power divider with the power ratio of 2 : 1 is designed, fabricated and measured. The measured results show good agreements with the simulated ones. © Koninklijke Brill NV, Leiden, 2011.

Song H.,University of Electronic Science and Technology of China
International Journal of Human-Computer Interaction | Year: 2012

The field of view (FOV) restricted displays are becoming more prevalent in daily use, such as touch-screen-based smart phones; ultramobile PCs; and, to some extent, head-mounted displays. All of these displays occupy significantly smaller portions of a user's FOV compared to standard desktop and laptop displays. Prior research has shown that there is an effect of display size, which is related with display FOV, on movement time (MT) when performing pointing tasks. However, there has yet to be a detailed, quantitative study of how display FOV affects MT across a wide range of FOV values. In the present study two user experiments are conducted, and it is found that Fitts' law is no longer adequate for modeling MT if the display FOV is restricted below a certain value, which we call the critical size. A new Fitts'-FOV model is proposed to extend Fitts' law beyond this critical size to restricted display FOV conditions. The results showed that the new model works as both a descriptive and a predictive model for restricted display FOV conditions. © 2012 Copyright Taylor and Francis Group, LLC.

Levitin G.,University of Electronic Science and Technology of China | Amari S.V.,Relex Software
Reliability Engineering and System Safety | Year: 2010

The paper presents an approximation algorithm for evaluating cdf of time-to-failure for k-out-of-n systems with shared spare elements. The working and spare elements can have different arbitrary distributions of time-to-failure. Different spare elements can be in different standby modes: cold, hot and warm. The algorithm is based on a universal generating function approach. It is shown that for small k the algorithm outperforms simulation. © 2009 Elsevier Ltd. All rights reserved.

Liang D.,University of Electronic Science and Technology of China | Liu D.,Southwest Jiaotong University
IEEE Transactions on Fuzzy Systems | Year: 2015

Decision-theoretic rough sets (DTRSs) play a crucial role in risk decision-making problems. With respect to the minimum expected risk, DTRSs deduce the rules of three-way decisions. Considering the new expression of evaluation information with hesitant fuzzy sets (HFSs), we introduce HFSs into DTRSs and explore their decision mechanisms. More specifically, we take into account the losses of DTRSs with hesitant fuzzy elements and propose a new model of hesitant fuzzy decision-theoretic rough sets (HFDTRSs). Some properties of the expected losses and their corresponding scores are carefully investigated under the hesitant fuzzy information. Three-way decisions and the associated cost of each object are further derived. With the above analysis, a novel risk decision-making method with the aid of HFDTRSs is developed. Besides the three-way decisions with DTRSs, the method investigates the ranking and resource allocation by utilizing the associated costs of alternatives and multiobjective 0-1 integer programming. Our study also offers a solution in the aspect of determining losses of DTRS and extends the range of applications. © 1993-2012 IEEE.

Duan D.W.,Chongqing University | Rao Y-J.,Chongqing University | Rao Y-J.,University of Electronic Science and Technology of China | Zhu T.,Chongqing University
Journal of the Optical Society of America B: Optical Physics | Year: 2012

A compact, all-fiber, open-cavity Fabry-Perot interferometer gas refractometer formed by fusion splicing a short section of single-mode fiber (SMF) between two sections of SMFs with a large lateral offset is proposed. Only simple fabrication steps including cleaving and fusion splicing are involved, so the fabrication is easy, safe, and cost effective. Such fabricated sensors have been successfully demonstrated as gas refractometers having a refractive index response of high sensitivity (~1540nm/RIU), good linearity, and high repeatability. Temperature evaluations also show that this kind of interferometer has a very low thermal sensitivity. © 2012 Optical Society of America.

Levitin G.,University of Electronic Science and Technology of China | Hausken K.,University of Stavanger
Reliability Engineering and System Safety | Year: 2010

The article considers defense resource allocation in a system exposed to external intentional attack. The defender distributes its resource between deploying redundant elements and their protection from attacks. The attacker observes all the elements and tries to detect the unprotected elements. All the detected unprotected elements are destroyed with negligible effort. The attacker then distributes its effort evenly among all of the undetected elements or among elements from a chosen subset of undetected elements. The vulnerability of each element is determined by an attacker-defender contest success function depending on the resources allocated to protection and attack efforts and on the contest intensity. The expected damage caused by the attack is evaluated as system unsupplied demand. The article studies the influence of the unprotected elements' detection probability on the optimal resource distribution. © 2010 Elsevier Ltd. All rights reserved.

Yu L.,University of Electronic Science and Technology of China | Yu L.,CAS Academy of Mathematics and Systems Science | Yu L.,Hangzhou Normal University
Information Sciences | Year: 2012

In this paper, a novel evolutionary programming (EP) based asymmetric weighted least squares support vector machine (LSSVM) ensemble learning methodology is proposed for software repository mining. In this methodology, an asymmetric weighted LSSVM model is first proposed. Then the process of building the EP-based asymmetric weighted LSSVM ensemble learning methodology is described in detail. Two publicly available software defect datasets are finally used for illustration and verification of the effectiveness of the proposed EP-based asymmetric weighted LSSVM ensemble learning methodology. Experimental results reveal that the proposed EP-based asymmetric weighted LSSVM ensemble learning methodology can produce promising classification accuracy in software repository mining, relative to other classification methods listed in this study. © 2011 Elsevier Inc. All rights reserved.

Guo S.,Hunan Normal University | Kendrick K.M.,University of Electronic Science and Technology of China | Yu R.,South China Normal University | Wang H.-L.S.,National Taiwan University | And 2 more authors.
Human Brain Mapping | Year: 2014

There is still no clear consensus as to which of the many functional and structural changes in the brain in schizophrenia are of most importance, although the main focus to date has been on those in the frontal and cingulate cortices. In the present study, we have used a novel holistic approach to identify brain-wide functional connectivity changes in medicated schizophrenia patients, and functional connectivity changes were analyzed using resting-state fMRI data from 69 medicated schizophrenia patients and 62 healthy controls. As far as we are aware, this is the largest population reported in the literature for a resting-state study. Voxel-based morphometry was also used to investigate gray and white matter volume changes. Changes were correlated with illness duration/symptom severity and a support vector machine analysis assessed predictive validity. A network involving the inferior parietal lobule, superior parietal gyrus, precuneus, superior marginal, and angular gyri was by far the most affected (68% predictive validity compared with 82% using all connections) and different components correlated with illness duration and positive and negative symptom severity. Smaller changes occurred in emotional memory and sensory and motor processing networks along with weakened interhemispheric connections. Our findings identify the key functional circuitry altered in schizophrenia involving the default network midline cortical system and the cortical mirror neuron system, both playing important roles in sensory and cognitive processing and particularly self-processing, all of which are affected in this disorder. Interestingly, the functional connectivity changes with the strongest links to schizophrenia involved parietal rather than frontal regions. Hum Brain Mapp 35:123-139, 2014. © 2012 Wiley Periodicals, Inc.

Hong L.,University of Electronic Science and Technology of China
Chaos (Woodbury, N.Y.) | Year: 2012

In this paper, we investigate a synchronization-based, data-driven clustering approach for the analysis of functional magnetic resonance imaging (fMRI) data, and specifically for detecting functional activation from fMRI data. We first define a new measure of similarity between all pairs of data points (i.e., time series of voxels) integrating both complete phase synchronization and amplitude correlation. These pairwise similarities are taken as the coupling between a set of Kuramoto oscillators, which in turn evolve according to a nearest-neighbor rule. As the network evolves, similar data points naturally synchronize with each other, and distinct clusters will emerge. The clustering behavior of the interaction network of the coupled oscillators, therefore, mirrors the clustering property of the original multiple time series. The clustered regions whose cross-correlation coefficients are much greater than other regions are considered as the functionally activated brain regions. The analysis of fMRI data in auditory and visual areas shows that the recognized brain functional activations are in complete correspondence with those from the general linear model of statistical parametric mapping, but with a significantly lower time complexity. We further compare our results with those from traditional K-means approach, and find that our new clustering approach can distinguish between different response patterns more accurately and efficiently than the K-means approach, and therefore more suitable in detecting functional activation from event-related experimental fMRI data.

Chen W.,University of Michigan | Chen W.,New York University | Shao Y.,University of Michigan | Li X.,University of Michigan | And 2 more authors.
Nano Today | Year: 2014

During embryogenesis and tissue maintenance and repair in an adult organism, a myriad of stem cells are regulated by their surrounding extracellular matrix (ECM) enriched with tissue/organ-specific nanoscale topographical cues to adopt different fates and functions. Attributed to their capability of self-renewal and differentiation into most types of somatic cells, stem cells also hold tremendous promise for regenerative medicine and drug screening. However, a major challenge remains as to achieve fate control of stem cells in vitro with high specificity and yield. Recent exciting advances in nanotechnology and materials science have enabled versatile, robust, and large-scale stem cell engineering in vitro through developments of synthetic nanotopographical surfaces mimicking topological features of stem cell niches. In addition to generating new insights for stem cell biology and embryonic development, this effort opens up unlimited opportunities for innovations in stem cell-based applications. This review is therefore to provide a summary of recent progress along this research direction, with perspectives focusing on emerging methods for generating nanotopographical surfaces and their applications in stem cell research. Furthermore, we provide a review of classical as well as emerging cellular mechano-sensing and -transduction mechanisms underlying stem cell nanotopography sensitivity and also give some hypotheses in regard to how a multitude of signaling events in cellular mechanotransduction may converge and be integrated into core pathways controlling stem cell fate in response to extracellular nanotopography. ©2014 Elsevier Ltd. All rights reserved.

Xiao M.,University of Electronic Science and Technology of China
Information Processing Letters | Year: 2010

The minimum 3-way cut problem in an edge-weighted hypergraph is to find a partition of the vertices into 3 nonempty sets minimizing the total weight of hyperedges that have at least two endpoints in two different sets. In this paper we show that a minimum 3-way cut in hypergraphs can be found by using O(n 3) hypergraph minimum (s, t) cut computations, where n is the number of vertices in the hypergraph. Our simple algorithm is the first polynomial-time algorithm for finding minimum 3-way cuts in hypergraphs. © 2010 Elsevier B.V. All rights reserved.

Zhang G.,University of Electronic Science and Technology of China | James M.R.,Australian National University
IEEE Transactions on Automatic Control | Year: 2011

The purpose of this paper is to study and design direct and indirect couplings for use in coherent feedback control of a class of linear quantum stochastic systems. A general physical model for a nominal linear quantum system coupled directly and indirectly to external systems is presented. Fundamental properties of stability, dissipation, passivity, and gain for this class of linear quantum models are presented and characterized using complex Lyapunov equations and linear matrix inequalities (LMIs). Coherent H∞ and LQG synthesis methods are extended to accommodate direct couplings using multistep optimization. Examples are given to illustrate the results. © 2011 IEEE.

Feng Z.,University of Science and Technology Beijing | Zuo M.J.,University of Electronic Science and Technology of China | Zuo M.J.,University of Alberta
Mechanical Systems and Signal Processing | Year: 2013

Torsional vibration signals are theoretically free from the amplitude modulation effect caused by time variant vibration transfer paths due to the rotation of planet carrier and sun gear, and therefore their spectral structure are simpler than transverse vibration signals. Thus, it is potentially easy and effective to diagnose planetary gearbox faults via torsional vibration signal analysis. We give explicit equations to model torsional vibration signals, considering both distributed gear faults (like manufacturing or assembly errors) and local gear faults (like pitting, crack or breakage of one tooth), and derive the characteristics of both the traditional Fourier spectrum and the proposed demodulated spectra of amplitude envelope and instantaneous frequency. These derivations are not only effective to diagnose single gear fault of planetary gearboxes, but can also be generalized to detect and locate multiple gear faults. We validate experimentally the signal models, as well as the Fourier spectral analysis and demodulation analysis methods. © 2012 Elsevier Ltd.

Rao Y.,University of Electronic Science and Technology of China
Visual Computer | Year: 2015

To efficiently locate identical objects in heterogeneous cameras and possibly propagate reliable information between cameras and refine detection, many techniques were used to recognize vehicles. In this paper, we investigate several key problems and present a novel approach for automatic vehicle recognition (AVR) in multiple cameras for video surveillance application. We propose a level-based region comparison algorithm to AVR in multiple cameras. For improving the recognition accuracy, new license plate recognition method is also proposed. Experimental results show that the proposed algorithm is simple and efficient, and the quality of the composed image can be comparable with the results of the state-of-the-art methods. © 2014, Springer-Verlag Berlin Heidelberg.

Fu X.,University of Electronic Science and Technology of China
International Journal of Network Security | Year: 2015

In Ciphertext Policy Attribute Based Encryption (CP-ABE) scheme, a user's private key is associated with a set of attributes, and the sensitive data are encrypted under an access structure over attributes, only if the users whose attributes satisfy the access structure associated with the ciphertext can decrypt the ciphertext data. However, a limitation of the existing CP-ABE schemes is that it does not support transforming access structure provided that the encrypted data are not decrypted. In this work, we proposed Ciphertext Policy Attribute Based Proxy Re-Encryption (CP-ABPRE) scheme which allows to transform access structure associated with the original cipher-text without decrypting it through an honest and curious proxy such as the cloud storage server that re-encrypts the original ciphertext under another access structure such that only if the users whose attributes satisfy the new access structure can decrypt the re-encrypted ciphertext. Security of the proposed scheme is based on the generic bilinear group model. Performance evaluation shows the proposed scheme is efficient.

Chen X.,University of Electronic Science and Technology of China
Mobile Information Systems | Year: 2015

The key to determining the network service level of telecom operators is resource allocation for mobile phone base station maintenance (MPBSM). Given intense market competition and higher consumer requirements for network service levels, an increasing proportion of resources have been allocated to MPBSM. Maintenance costs account for the rising fraction of direct costs, and the management of MPBSM resource allocation presents special challenges to telecom operators. China Mobile is the largest telecom operator in the world. Its subsidiary, China Mobile Sichuan, is the first in China to use revenue management in improving MPBSM resource allocation. On the basis of comprehensive revenue (including both economic revenue and social revenue), the subsidiary established a classification model of its base stations. The model scientifically classifies more than 25,000 base stations according to comprehensive revenue. China Mobile Sichuan also conducted differentiation allocation of MPBSM resources on the basis of the classification results. Furthermore, it optimized the assessment system of the telecom base stations to establish an assurance system for the use of MPBSM resources. After half-year implementation, the cell availability of both VIP base stations and total base stations significantly improved. The optimization also reduced economic losses to RMB 10.134 million, and enhanced customer satisfaction with network service by 3.2%. Copyright © 2015 Xu Chen.

Zheng K.,Beijing University of Posts and Telecommunications | Zheng K.,Orange S.A. | Hu F.,Beijing University of Posts and Telecommunications | Wang W.,Catalonia Technology Center of Telecomunications | And 2 more authors.
IEEE Communications Magazine | Year: 2012

Machine-to-machine (M2M) communications are expected to provide ubiquitous connectivity between machines without the need of human intervention. To support such a large number of autonomous devices, the M2M system architecture needs to be extremely power and spectrally efficient. This article thus briefly reviews the features of M2M services in the third generation (3G) long-term evolution and its advancement (LTE-Advanced) networks. Architectural enhancements are then presented for supporting M2M services in LTE-Advanced cellular networks. To increase spectral efficiency, the same spectrum is expected to be utilized for humanto-human (H2H) communications as well as M2M communications. We therefore present various radio resource allocation schemes and quantify their utility in LTE-Advanced cellular networks. System-level simulation results are provided to validate the performance effectiveness of M2M communications in LTE-Advanced cellular networks. © 2012 IEEE.

Luo X.,University of Electronic Science and Technology of China | Ma J.-G.,Tianjin University | Li E.-P.,Zhejiang University
IEEE Microwave and Wireless Components Letters | Year: 2011

In this letter, a compact wideband bandpass filter with a wide stopband is proposed. The filter is composed of three parts: a half-wavelength (λ/2) microstrip resonator with a loaded broadside-coupled microstrip/CPW (BCMC) stub, two λ/4 I/O feeding-lines, and two microstrip short-stubs. The loaded BCMC stub can not only introduce the perturbation to affect the λ/2 microstrip resonator acting as a dual-mode resonator, but also provide two transmission zeros to improve the upper passband selectivity and suppress the first odd-mode spurious. Then, to avoid the first even-mode spurious, two microstrip short-stubs are employed to obtain another transmission zero. Meanwhile, two λ/4 I/O feeding-lines are employed to obtain strong passband enhancement around the dual-resonances. To verify the mechanism mentioned above, a bandpass filter is designed. The proposed filter has the merits of low insertion loss, good passband selectivity, wide stopband, flat group delay, and a compact size. © 2011 IEEE.

Luo X.,University of Electronic Science and Technology of China | Ma J.-G.,Tianjin University | Yeo K.S.,Nanyang Technological University | Li E.-P.,Zhejiang University
IEEE Transactions on Microwave Theory and Techniques | Year: 2011

In this paper, compact ultra-wideband (UWB) bandpass filters with ultra-narrow dual- and quad-notched bands are proposed using the broadside-coupled microstrip/coplanar waveguide (CPW) structure. The multiple-modes UWB operation is obtained through the CPW detached-mode resonator (DMR) and broadside-coupled microstrip/CPW transition. To avoid the existing interferences such as the wireless local-area network signals (i.e., 5.2- and 5.8-GHz bands) in the UWB passband simultaneously, dual-notched bands can be finely employed and independently adjusted by the embedded quarter-wavelength (λ/4) CPW resonators and the λ/4 meander slot-line inserted in the DMR, respectively. To further cancel the interferences from the 3.5-GHz worldwide interoperability for microwave access and 6.8-GHz RF identification communication, the λ/4 meander defected microstrip structure is employed. Based on the structures mentioned above, a series of UWB bandpass filters with dual- and quad-notched bands are then designed and fabricated. With good passband/stopband performances, compact size, and low cost, the proposed filters are attractive for the practical applications. © 2006 IEEE.

Xiao M.,University of Electronic Science and Technology of China
Theory of Computing Systems | Year: 2010

Given a graph G=(V,E) with n vertices and m edges, and a subset T of k vertices called terminals, the Edge (respectively, Vertex) Multiterminal Cut problem is to find a set of at most l edges (non-terminal vertices), whose removal from G separates each terminal from all the others. These two problems are NP-hard for k≥3 but well-known to be polynomial-time solvable for k=2 by the flow technique. In this paper, based on a notion farthest minimum isolating cut, we design several simple and improved algorithms for Multiterminal Cut. We show that Edge Multiterminal Cut can be solved in O(2lkT(n,m)) time and Vertex Multiterminal Cut can be solved in O(klT(n,m)) time, where T(n,m)=O(min (n2/3,m1/2)m) is the running time of finding a minimum (s,t) cut in an unweighted graph. Furthermore, the running time bounds of our algorithms can be further reduced for small values of k: Edge 3-Terminal Cut can be solved in O(1.415lT(n,m)) time, and Vertex {3,4,5,6}-Terminal Cuts can be solved in O(2.059lT(n,m)), O(2.772lT(n,m)), O(3.349lT(n,m)) and O(3.857lT(n,m)) time respectively. Our results on Multiterminal Cut can also be used to obtain faster algorithms for Multicut: -time algorithm for Edge Multicut and O((2k)k+l/2T(n,m))-time algorithm for Vertex Multicut. © 2009 Springer Science+Business Media, LLC.

Lu L.,University of Electronic Science and Technology of China
Jisuanji Xuebao/Chinese Journal of Computers | Year: 2015

As Radio Frequency Identification (RFID) systems have been enormously applied in fields like commerce and logistics, a wide spectrum applications call for Privacy-Preserving Authentication (PPA) in RFID systems, which require a legitimate reader to share secret keys with one or group of tags. With open wireless channels, an adversary can easily obtain keys sent to tags by the reader. Moreover, existing key-agreement approaches cannot be employed in RFIDs as tags are usually resource-constraint. Furthermore, keys implanted by manufacturer cannot be considered as secure due to two-fold reasons: the most trustworthy keys are those generated by users themselves and the key-escrow on the manufacturer incurs key-leaking problem. Hence, it is very challenging to generate shared secret keys among a valid reader and tags wirelessly and securely. In this paper, we propose an innovative wireless key generation scheme, called WiKey, with which a legitimate reader can generate secret keys among itself and tags by effectively utilizing the asymmetry of communication channels of RFID systems. WiKey is a very light-weighted protocol and can be implemented on current RFID systems. Through intensive security analysis, we show that WiKey is an efficient and strong protection for PPAs in RFID systems. Moreover, the implementation on WISP RFID tags and experiment results illustrate the feasibility and efficacy of WiKey. ©, 2015, Science Press. All right reserved.

Wang W.-Q.,University of Electronic Science and Technology of China
IEEE Transactions on Aerospace and Electronic Systems | Year: 2014

Phased-array is widely used in communication, radar, and navigation systems, but the beam steering is fixed in an angle for all range cells. Frequency diverse array (FDA) provides a range-dependent beamforming, but it cannot estimate directly both the range and angle of a target. This paper proposes a subarray-based FDA radar, with an aim to localize the target in the range-angle domain.We divide the whole FDA array into two subarrays, which employ two different frequency increments. In doing so, the target's range and angle are estimated directly from the transmit-receive beamforming output peak. The estimation performance is examined by analyzing the minimum mean variance square error (MMSE) and the Cramér-Rao lower bound (CRLB) versus signal-to-noise ratio (SNR). The corresponding transmit-receive beampattern and signal-to-interference plus noise ratio (SINR) are also formalized. Moreover, the CRLB can be used to optimally design the frequency increments. The effectiveness is verified by simulation results. © 2014 IEEE.

Xiao F.,University of Electronic Science and Technology of China
IEEE Transactions on Circuits and Systems II: Express Briefs | Year: 2014

In this brief, a fast design technique based on a multiband mapping relation is discussed for infinite-impulse-response digital filters with a general Chebyshev characteristic, which is suitable for single-and multiband operations. Each bandwidth and the ripple in it can be accurately controlled. Without increasing the order of the filters, the out-of-band performance of the filters can be easily adjusted by appropriately placing transmission zeros wherever they are desired. In addition, complex transmission zeros can also be introduced to improve the group delay to some extent. The proposed technique is analytical and easy to implement. © 2014 IEEE.

Zhang X.-C.,University of Electronic Science and Technology of China
Proceedings of the IEEE Conference on Decision and Control | Year: 2013

The cubature Kalman filter (CKF) is more preferred over the unscented Kalman filter (UKF) for its more stable performance. The CKF employs a third-degree sphericalradial cubature rule to numerically compute the integrals encountered in nonlinear filtering problems. The third-degree cubature rule-based filter, however, is not accurate enough in many real-life applications. Moreover, the spherical cubature formula that has been used to develop the CKF has some drawbacks in computation, most notably its inconvenient properties in high-dimensional state estimation problems. To tackle these problems, a new approach to nonlinear state estimation using only an embedded cubature rule, which we have named the square-root embedded cubature Kalman filter (SECKF) is proposed in this work. The experimental results, presented herein, demonstrate the superior performance of the SECKF over conventional nonlinear filters. © 2013 IEEE.

Fang J.,University of Electronic Science and Technology of China | Wen C.,University of North Texas | Pavur R.,University of North Texas
Cyberpsychology, Behavior, and Social Networking | Year: 2012

Prior research involving response rates in Web-based surveys has not adequately addressed the effect of the reputation of a sponsoring corporation that contracts with a survey provider. This study investigates the effect of two factors, namely, the reputation of a survey's provider and the reputation of a survey's sponsoring corporation, on the willingness of potential respondents to participate in a Web survey. Results of an experimental design with these two factors reveal that the sponsoring corporation's and the survey provider's strong reputations can induce potential respondents to participate in a Web survey. A sponsoring corporation's reputation has a greater effect on the participation willingness of potential respondents of a Web survey than the reputation of the survey provider. A sponsoring corporation with a weak reputation who contracts with a survey provider having a strong reputation results in increased participation willingness from potential respondents if the identity of the sponsoring corporation is disguised in a survey. This study identifies the most effective strategy to increase participation willingness for a Web-based survey by considering both the reputations of the sponsoring corporation and survey provider and whether to reveal their identities. © Copyright 2012, Mary Ann Liebert, Inc.

Zhang Y.,University of Electronic Science and Technology of China
BMC bioinformatics | Year: 2012

Pairwise statistical significance has been recognized to be able to accurately identify related sequences, which is a very important cornerstone procedure in numerous bioinformatics applications. However, it is both computationally and data intensive, which poses a big challenge in terms of performance and scalability. We present a GPU implementation to accelerate pairwise statistical significance estimation of local sequence alignment using standard substitution matrices. By carefully studying the algorithm's data access characteristics, we developed a tile-based scheme that can produce a contiguous data access in the GPU global memory and sustain a large number of threads to achieve a high GPU occupancy. We further extend the parallelization technique to estimate pairwise statistical significance using position-specific substitution matrices, which has earlier demonstrated significantly better sequence comparison accuracy than using standard substitution matrices. The implementation is also extended to take advantage of dual-GPUs. We observe end-to-end speedups of nearly 250 (370) × using single-GPU Tesla C2050 GPU (dual-Tesla C2050) over the CPU implementation using Intel Corei7 CPU 920 processor. Harvesting the high performance of modern GPUs is a promising approach to accelerate pairwise statistical significance estimation for local sequence alignment.

Guo X.,Seoul National University | Guo X.,University of Electronic Science and Technology of China
Journal of Biophotonics | Year: 2012

Optical Surface plasmon resonance (SPR) biosensors represent the most advanced and developed optical label-free biosensor technology. Optical SPR biosensors are a powerful detection and analysis tool that has vast applications in environmental protection, biotechnology, medical diagnostics, drug screening, food safety and security. This article reviews the recent development of SPR biosensor techniques, including bulk SPR and localized SPR (LSPR) biosensors, for detecting interactions between an analyte of interest in solution and a biomolecular recognition. The concepts of bulk and localized SPs and the working principles of both sensing techniques are introduced. Major sensing advances on biorecognition elements, measurement formats, and sensing platforms are presented. Finally, the discussions on both biosensor techniques as well as comparison of both SPR sensing techniques are made. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xiao F.,University of Electronic Science and Technology of China
International Journal of Circuit Theory and Applications | Year: 2015

Recently, direct synthesis techniques (DSTs) have been presented for filter synthesis. Unlike conventional synthesis techniques, DSTs derive the filtering polynomials of the filters to be synthesized directly in their own frequency domain. These filtering polynomials are real coefficient so that they might find applications in various fields. Furthermore, DSTs might be used to customize filters with a more complex frequency response, such as asymmetric frequency response or multi-band frequency response. In this paper, DSTs are compared with some well-known filter synthesis techniques. Then, the application of DSTs in the design of lumped-element LC filters, distributed-element filters, active RC filters, and infinite impulse response digital filters with complex frequency response is discussed. Some examples are presented for demonstration. © 2015 John Wiley & Sons, Ltd.

Chen K.X.,University of Electronic Science and Technology of China | Chan H.P.,City University of Hong Kong | Chan W.Y.,City University of Hong Kong
Journal of Lightwave Technology | Year: 2013

This paper presents a detailed design, fabrication, and thermal tuning characteristics of a polarization independent tunable interleaver. Its operation principle is by using a double layer waveguide structure and vertically coupled polarization splitters to achieve a polarization diversity configuration so as to manipulate separately transverse electric (TE) and transverse magnetic (TM) polarization light signals. The fabricated interleaver is with two types of tuning manner. First, its center wavelength can be adjusted by changing the substrate temperature, which can be used to align the International Telecommunication Union grid for the TM polarization modes. Second, the center wavelength in the TE output spectra can be tuned to meet the ones in the TM output spectra by using thermo-optic effect to fine tune the mode index of the upper channel waveguide. The fabricated device was 18 mm × 9 mm and exhibited complete polarization independences with respect to center wavelength and channel spacing with very little tuning power consumption of ∼0.6 mW over the entire C band. The tuning range of the center wavelength was about 1.4 nm. © 2013 IEEE.

Yu J.,University of Electronic Science and Technology of China | Yu J.,Peking University | Wang L.,Peking University | Yu M.,North China Electrical Power University
International Journal of Robust and Nonlinear Control | Year: 2011

Stabilization problems of networked control systems (NCSs) with bounded packet losses and transmission delays are addressed. We model such NCSs as a class of switched systems, and establish stabilizing conditions in the form of matrix inequalities by using packet-loss dependent Lyapunov functions. By solving the inequalities, packet-loss dependent controllers are designed for two types of packet-loss processes: one is an arbitrary packet-loss process, and the other is a Markovian packet-loss process. Several numerical examples and simulations are worked out to demonstrate the effectiveness of the proposed design techniques. © 2010 John Wiley & Sons, Ltd.

Pang X.-F.,University of Electronic Science and Technology of China
International Journal of Modern Physics B | Year: 2013

The mechanism and properties of electron transfer along protein molecules at finite temperature T ≠ 0 in the life systems are studied using nonlinear theory of bio-energy transport and Green function method, in which the electrons are transferred from donors to acceptors in virtue of the supersound soliton excited by the energy released in ATP hydrolysis. The electron transfer is, in essence, a process of oxidation-reduction reaction. In this study we first give the Hamiltonian and wavefunction of the system and find out the soliton solution of the dynamical equation in the protein molecules with finite temperature, and obtain the dynamical coefficient of the electron transfer. The results show that the speed of the electron transfer is related to the velocity of motion of the soliton, distribution of electrons in the donor and acceptor as well as the interaction strength among them. We finally concluded the changed rule of electric current, arising from the electron transfer, with increasing time. These results are useful in molecular and chemical biology. © World Scientific Publishing Company.

Kou G.,University of Electronic Science and Technology of China | Shi Y.,Chinese Academy of Sciences | Shi Y.,University of Nebraska at Omaha | Wang S.,CAS Academy of Mathematics and Systems Science
Decision Support Systems | Year: 2011

Integration of MCDM with DSS brings benefit to both fields. MCDM tools are useful in identifying and evaluating incompatible alternatives for DSS, while DSS can implement MCDM approaches and help maintain and retrieve MCDM models. Over the years, MCDM has made considerable contribution to the development of various DSS subspecialties. This special issue on Multiple Criteria Decision Making and Decision Support Systems consists of 9 selected papers from the 20th International Conference on Multiple Criteria Decision Making. The guest editors highlight the key ideas and contributions of the papers in the special issue. © 2010 Elsevier B.V. All rights reserved.

Peng X.,University of Electronic Science and Technology of China | Peng X.,University of Western Australia | Bennamoun M.,University of Western Australia | Mian A.S.,University of Western Australia
Pattern Recognition | Year: 2011

Nose tip detection in range images is a specific facial feature detection problem that is highly important for 3D face recognition. In this paper, we propose a nose tip detection method that has the following three characteristics. First, it does not require training and does not rely on any particular model. Second, it can deal with both frontal and non-frontal poses. Finally, it is quite fast, requiring only seconds to process an image of 100200 pixels (in both x and y dimensions) with a MATLAB implementation. A complexity analysis shows that most of the computations involved in the proposed algorithm are simple. Thus, if implemented in hardware (such as a GPU implementation), the proposed method should be able to work in real time. We tested the proposed method extensively on synthetic image data rendered by a 3D head model and real data using FRGC v2.0 data set. Experimental results show that the proposed method is robust to many scenarios that are encountered in common face recognition applications (e.g., surveillance). A high detection rate of 99.43% was obtained on FRGC v2.0 data set. Furthermore, the proposed method can be used to coarsely estimate the roll, yaw, and pitch angles of the face pose. © 2010 Elsevier Ltd. All rights reserved.

Zhu W.,Zhangzhou Normal University | Wang S.,University of Electronic Science and Technology of China
International Journal of Machine Learning and Cybernetics | Year: 2011

Rough set theory is a useful tool for dealing with the vagueness, granularity and uncertainty in information systems. This paper connects generalized rough sets based on relations with matroid theory. We define the upper approximation number to induce a matroid from a relation. Therefore, many matroidal approaches can be used to study generalized rough sets based on relations. Specifically, with the rank function of the matroid induced by a relation, we construct a pair of approximation operators, namely, matroid approximation operators. The matroid approximation operators present some unique properties which do not exist in the existing approximation operators. On the other hand, we present an approach to induce a relation from a matroid. Moreover, the relationship between two inductions is studied. © 2011 Springer-Verlag.

Li L.-W.,University of Electronic Science and Technology of China | Li L.-W.,National University of Singapore | Li Y.-N.,National University of Singapore | Yeo T.S.,National University of Singapore | And 2 more authors.
Applied Physics Letters | Year: 2010

A broad bandwidth and high gain rectangular patch antenna was specifically designed in this paper using planar-patterned metamaterial concepts. Based on an ordinary patch antenna, the antenna has isolated triangle gaps and crossed strip-line gaps etched on the metal patch and ground plane, respectively. Demonstrated to have left-handed characteristics, the patterned metal patch and finite ground plane form a coupled capacitive-inductive circuit of negative index metamaterial. It is shown to have great impact on the antenna performance enhancement in terms of the bandwidth significantly broadened from a few hundred megahertz to a few gigahertz, and also in terms of high efficiency, low loss, and low voltage standing wave ratio. Experimental data show a reasonably good agreement between the simulation and measured results. This antenna has strong radiation in the horizontal direction for some specific applications within the entire band. © 2010 American Institute of Physics.

Liu Y.,University of Electronic Science and Technology of China | Yu Y.,University of Illinois at Urbana - Champaign
IEEE Transactions on Visualization and Computer Graphics | Year: 2012

In this paper, we present a robust and accurate algorithm for interactive image segmentation. The level set method is clearly advantageous for image objects with a complex topology and fragmented appearance. Our method integrates discriminative classification models and distance transforms with the level set method to avoid local minima and better snap to true object boundaries. The level set function approximates a transformed version of pixelwise posterior probabilities of being part of a target object. The evolution of its zero level set is driven by three force terms, region force, edge field force, and curvature force. These forces are based on a probabilistic classifier and an unsigned distance transform of salient edges. We further propose a technique that improves the performance of both the probabilistic classifier and the level set method over multiple passes. It makes the final object segmentation less sensitive to user interactions. Experiments and comparisons demonstrate the effectiveness of our method. © 2012 IEEE.

Li F.,University of Electronic Science and Technology of China | Li F.,Fujian Normal University | Khan M.K.,King Saud University
Future Generation Computer Systems | Year: 2012

Signcryption is a high performance cryptographic primitive that fulfills both the functions of digital signature and public key encryption simultaneously, at a cost significantly lower than that required by the traditional signature-then-encryption approach. In this paper, we introduce biometrics into identity-based signcryption. We formalize the notion of biometric identity-based signcryption and propose an efficient biometric identity-based signcryption scheme that uses biometric information to construct the public key. We prove that our scheme satisfies confidentiality and unforgeability in the random oracle model. We show that both the computational costs and the communication overheads of our scheme are lower than those of the signature-then-encryption approach. © 2010 Elsevier B.V. All rights reserved.

Fang J.,University of Electronic Science and Technology of China | Wen C.,Eastern Illinois University | Prybutok V.,University of North Texas
Computers in Human Behavior | Year: 2014

Investigation of the underlying mechanisms responsible for measurement variance has received little attention. The primary objective of this study is to examine whether paper and social media surveys produce convergent results and investigate the underlying psychological mechanisms for the potential measurement nonequivalence. Particularly, we explored the role of social desirability and satisficing on the measurement results. We collected data via five different survey modes, including paper survey, ad hoc Web survey, online forum (message boards)-based, SNS-based and microblog-based surveys. The findings show that socially desirable responding does not lead to inconsistent results. Rather we found that satisficing causes inconsistent results in paper versus online surveys. Sociability reduces the possibility of engaging in satisficing that results in inconsistent results between traditional Web surveys and social media-based Web surveys. © 2013 Elsevier Ltd. All rights reserved.

Peng J.,University of Electronic Science and Technology of China
Bioinspiration and Biomimetics | Year: 2015

Weakly electric fish sense their surroundings in complete darkness by their active electrolocation system. For biologists, the active electrolocation system has been investigated for near 60 years. And for engineers, bio-inspired active electrolocation sensor has been investigated for about 20 years. But how the amplitude information response will be affected by frequencies of detecting electric fields in the active electrolocation system was rarely investigated. In this paper, an electrolocation experiment system has been built. The amplitude information-frequency characteristics (AIFC) of the electrolocation system for sinusoidal electric fields of varying frequencies have been investigated. We find that AIFC of the electrolocation system have relevance to the material properties and geometric features of the probed object and conductivity of surrounding water. Detect frequency dead zone (DFDZ) and frequency inflection point (FIP) of AIFC for the electrolocation system were found. The analysis model of the electrolocation system has been investigated for many years, but DFDZ and FIP of AIFC can be difficult to explain by those models. In order to explain those AIFC phenomena for the electrolocation system, a simple relaxation model based on Cole-Cole model which is not only a mathematical explanation but it is a physical one for the electrolocation system was advanced. We also advance a hypothesis for physical mechanism of weakly electrical fish electrolocation system. It may have reference value for physical mechanism of weakly electrical fish active electrolocation system. © 2015 IOP Publishing Ltd.

Li C.,North Carolina State University | Li C.,University of Electronic Science and Technology of China | Huang L.,North Carolina State University | Snigdha G.P.,North Carolina State University | And 2 more authors.
ACS Nano | Year: 2012

We report a synthesis of single-crystalline two-dimensional GeS nanosheets using vapor deposition processes and show that the growth behavior of the nanosheet is substantially different from those of other nanomaterials and thin films grown by vapor depositions. The nanosheet growth is subject to strong influences of the diffusion of source materials through the boundary layer of gas flows. This boundary layer diffusion is found to be the rate-determining step of the growth under typical experimental conditions, evidenced by a substantial dependence of the nanosheet's size on diffusion fluxes. We also find that high-quality GeS nanosheets can grow only in the diffusion-limited regime, as the crystalline quality substantially deteriorates when the rate-determining step is changed away from the boundary layer diffusion. We establish a simple model to analyze the diffusion dynamics in experiments. Our analysis uncovers an intuitive correlation of diffusion flux with the partial pressure of source materials, the flow rate of carrier gas, and the total pressure in the synthetic setup. The observed significant role of boundary layer diffusions in the growth is unique for nanosheets. It may be correlated with the high growth rate of GeS nanosheets, ∼3-5 μm/min, which is 1 order of magnitude higher than other nanomaterials (such as nanowires) and thin films. This fundamental understanding of the effect of boundary layer diffusions may generally apply to other chalcogenide nanosheets that can grow rapidly. It can provide useful guidance for the development of general paradigms to control the synthesis of nanosheets. © 2012 American Chemical Society.

Wang W.-Q.,University of Electronic Science and Technology of China
PLoS ONE | Year: 2015

High-precision radiometric calibration and synchronization compensation must be provided for distributed radar system due to separate transmitters and receivers. This paper proposes a transponder-aided joint radiometric calibration, motion compensation and synchronization for distributed radar remote sensing. As the transponder signal can be separated from the normal radar returns, it is used to calibrate the distributed radar for radiometry. Meanwhile, the distributed radar motion compensation and synchronization compensation algorithms are presented by utilizing the transponder signals. This method requires no hardware modifications to both the normal radar transmitter and receiver and no change to the operating pulse repetition frequency (PRF). The distributed radar radiometric calibration and synchronization compensation require only one transponder, but the motion compensation requires six transponders because there are six independent variables in the distributed radar geometry. Furthermore, a maximum likelihood method is used to estimate the transponder signal parameters. The proposed methods are verified by simulation results. © 2015 Wen-Qin Wang.

Tang Z.,Sichuan Agricultural University | Yang Z.,University of Electronic Science and Technology of China | Fu S.,Sichuan Agricultural University
Journal of Applied Genetics | Year: 2014

Hybrids derived from wheat (Triticum aestivum L.) × rye (Secale cereale L.) have been widely studied because of their important roles in wheat cultivar improvement. Repetitive sequences pAs1, pSc119.2, pTa-535, pTa71, CCS1, and pAWRC.1 are usually used as probes in fluorescence in situ hybridization (FISH) analysis of wheat, rye, and hybrids derived from wheat × rye. Usually, some of these repetitive sequences for FISH analysis were needed to be amplified from a bacterial plasmid, extracted from bacterial cells, and labeled by nick translation. Therefore, the conventional procedure of probe preparation using these repetitive sequences is time-consuming and labor-intensive. In this study, some appropriate oligonucleotide probes have been developed which can replace the roles of repetitive sequences pAs1, pSc119.2, pTa-535, pTa71, CCS1, and pAWRC.1 in FISH analysis of wheat, rye, and hybrids derived from wheat × rye. These oligonucleotides can be synthesized easily and cheaply. Therefore, FISH analysis of wheat and hybrids derived from wheat × rye using these oligonucleotide probes becomes easier and more economical. © 2014 Institute of Plant Genetics, Polish Academy of Sciences, Poznan.

Huang Y.,University of Electronic Science and Technology of China | Kou G.,Southwestern University of Finance and Economics
Decision Support Systems | Year: 2014

Identification of intrinsic characteristics and structure of high-dimensional data is an important task for financial analysis. This paper presents a kernel entropy manifold learning algorithm, which employs the information metric to measure the relationships between two financial data points and yields a reasonable low-dimensional representation of high-dimensional financial data. The proposed algorithm can also be used to describe the characteristics of a financial system by deriving the dynamical properties of the original data space. The experiment shows that the proposed algorithm cannot only improve the accuracy of financial early warning, but also provide objective criteria for explaining and predicting the stock market volatility. © 2014 The Authors.

Wang H.,University of Electronic Science and Technology of China
Tien Tzu Hsueh Pao/Acta Electronica Sinica | Year: 2015

The periodicity is a feature of science and engineering phenomena, so detecting periodicity from complex and noise-included samples and measuring its parameters are important topics in signal processing. Spectral correlation is a useful tool to find second-order periodicity of cyclostationary signals. This paper investigates the reasons, procedures and features using spectral correlation to analyze cyclicity. First, internal relations between main definitions in spectral correlation theory are summarized and mathematic diagrams reflecting their transforming or mapping relations are built. Then a method to calculate spectral correlation based on the diagrams is proposed. By analysis of single periodic signals and connections between periods and results in each operation, physical functions of cyclic autocorrelation, spectral correlation, limit periodic spectrum and cyclic frequency, etc, are interpreted. ©, 2015, Chinese Institute of Electronics. All right reserved.

Zhang C.,University of Electronic Science and Technology of China | Yi Z.,Sichuan University
Neurocomputing | Year: 2010

Self-nonself discrimination has long been the fundamental model of modern theoretical immunology. Based on this principle, some effective and efficient artificial immune algorithms have been proposed and applied to a wide range of engineering applications. Over the last few years, a new model called "danger theory" has been developed to challenge the classical self-nonself model. In this paper, a novel immune algorithm inspired by danger theory is proposed for solving on-line supervised two-class classification problems. The general framework of the proposed algorithm is described, and several essential issues related to the learning process are also discussed. Experiments based on both artificial data sets and real-world problems are carried out to visualize the learning process, as well as to evaluate the classification performance of our method. It is shown empirically by the experimental results that the proposed algorithm exhibits competitive classification accuracy and generalization capability. © 2010 Elsevier B.V. All rights reserved.

Wang W.-Q.,University of Electronic Science and Technology of China | Wang W.-Q.,Imperial College London
IEEE Sensors Journal | Year: 2015

Multiple-input multiple-output (MIMO) radar waveform diversity design has received much attention, but most of the existing waveforms lack a large time-bandwidth product and are difficult to be implemented by real-life hardwares. In this paper, we propose a large time-bandwidth product waveform diversity design scheme based on chirp rate diversity for MIMO radar. The proposed scheme can generate a large number of pseudo-orthogonal waveforms that have large time-bandwidth product, constant modulus, no range-Doppler coupling target response, good orthogonality, and Doppler tolerance. In addition, the waveforms are orthogonal on both transmit and receive. The waveform performance is in-depth analyzed with the correlation and ambiguity functions. Furthermore, the corresponding frequency demodulation in the receiver is also discussed. Numerical results validate the superiorities of the designed waveforms in MIMO radar applications. © 2001-2012 IEEE.

Liu X.,University of California at Santa Barbara | Wen W.,University of California at Santa Barbara | Wen W.,University of Electronic Science and Technology of China | Bazan G.C.,University of California at Santa Barbara
Advanced Materials | Year: 2012

An arylated-carbazole conjugated polymer with a deep HOMO level has been developed. Solar cells based on blends of PCX3 and PC71BM show efficiency of 3.9% with a Voc of 0.96 V. The device performance can be improved to 5.1% by using polar solvent treatment, most likely as a result of modified interfacial properties. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Feng P.X.,University of Electronic Science and Technology of China
Journal of Molecular Liquids | Year: 2014

The energy spectra of vibration of OH and HOH bonds in molecules in liquid water are calculated using the dynamic equation in nonlinearly self-trapping theory. The eigenenergies and eigenfunctions of the first, second, third and nth excited states of stretching vibration of OH bond as well as of first and second excited states of stretching and bending vibrations of HOH bond are obtained, respectively. From comparing them with those obtained in normal model and localized model we find that the calculated results approach more to the experimental values relative to those obtained from normal and local models. These results are helpful to explain well the optical properties of water. © 2014 Elsevier B.V.

Liu Z.,University of Electronic Science and Technology of China | Liu Z.,University of California at Berkeley | Tian L.,University of California at Berkeley | Liu S.,University of California at Berkeley | Waller L.,University of California at Berkeley
Journal of Biomedical Optics | Year: 2014

We demonstrate a single-camera imaging system that can simultaneously acquire brightfield, darkfield, and phase contrast images in real time. Our method uses computational illumination via a programmable light-emitting diode (LED) array at the source plane, providing flexible patterning of illumination angles. Brightfield, darkfield, and differential phase contrast images are obtained by changing the LED patterns, without any moving parts. Previous work with LED array illumination was only valid for static samples because the hardware speed was not fast enough to meet real-time acquisition and processing requirements. Here, we time multiplex patterns for each of the three contrast modes in order to image dynamic biological processes in all three contrast modes simultaneously. We demonstrate multicontrast operation at the maximum frame rate of our camera (50 Hz with 2160 × 2560 pixels). © The Authors.

Lin P.,University of Electronic Science and Technology of China | Ren W.,University of California at Riverside
Proceedings of the IEEE Conference on Decision and Control | Year: 2012

In this paper, a constrained consensus problem is studied in unbalanced networks in the presence of communication delays. Here each agent needs to lie in a closed convex set while reaching a consensus. The communication graphs considered are directed, dynamically changing, and not necessarily balanced and only the union of the graphs is assumed to be strongly connected among each time interval of a certain bounded length. The analysis is performed based on an undelayed equivalent system that is composed of a linear main body and an error auxiliary. It is showed that the error auxiliary vanishes as time evolves and the linear main body converges to a vector with an exponential rate as a separate system. It is also showed that the communication delays do not affect the consensus stability and consensus is achieved even though the communication delays are arbitrary bounded. © 2012 IEEE.

Zhang L.,Institute for Infocomm Research | Zhang R.,Institute for Infocomm Research | Liang Y.-C.,Institute for Infocomm Research | Liang Y.-C.,University of Electronic Science and Technology of China | And 2 more authors.
IEEE Transactions on Information Theory | Year: 2012

Owing to the special structure of the Gaussian multiple-input multiple-output (MIMO) broadcast channel (BC), the associated capacity region computation and beamforming optimization problems are typically non-convex, and thus cannot be solved directly. One feasible approach is to consider the respective dual multiple-access channel (MAC) problems, which are easier to deal with due to their convexity properties. The conventional BC-MAC duality has been established via BC-MAC signal transformation, and is applicable only for the case in which the MIMO BC is subject to a single transmit sum-power constraint. An alternative approach is based on minimax duality, which can be applied to the case of the sum-power constraint or per-antenna power constraint. In this paper, the conventional BC-MAC duality is extended to the general linear transmit covariance constraint (LTCC) case, which includes sum-power and per-antenna power constraints as special cases. The obtained general BC-MAC duality is applied to solve the capacity region computation for the MIMO BC and beamforming optimization for the multiple-input single-output (MISO) BC, respectively, with multiple LTCCs. The relationship between this new general BC-MAC duality and the minimax duality is also discussed, and it is shown that the general BC-MAC duality leads to simpler problem formulations. Moreover, the general BC-MAC duality is extended to deal with the case of nonlinear transmit covariance constraints in the MIMO BC. © 2006 IEEE.

Hu J.,University of Electronic Science and Technology of China | Zheng W.X.,University of Western Sydney
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2014

Cooperation and competition are two typical interactional relationships for intra-networks and inter-networks. This paper investigates the modeling of coopetition networks and the collective dynamics on such networks. The coopetition networks are firstly modeled by directed signed graphs. The evolutionary relationships among individuals on the coopetition networks are described by a neighbor-based dynamics model, which is also called multi-agent system (MAS). Then, under a weak connectivity assumption that the signed network has a spanning tree, some sufficient conditions are derived for the consensus, polarization or fragmentation behaviors of the MAS with the help of the structural balance theory. At the same time, signless Laplacian matrix and signed Laplacian matrix are introduced to analyze the collective dynamics of the MAS on coopetition networks. Finally, simulation results are provided to demonstrate the emergence of diverse collective behaviors on coopetition networks. © 2014 Elsevier B.V.

Vasan A.S.S.,University of Maryland University College | Long B.,University of Electronic Science and Technology of China | Pecht M.,University of Maryland University College | Pecht M.,City University of Hong Kong
IEEE Transactions on Industrial Electronics | Year: 2013

Analog circuits play a vital role in ensuring the availability of industrial systems. Unexpected circuit failures in such systems during field operation can have severe implications. To address this concern, we developed a method for detecting faulty circuit condition, isolating fault locations, and predicting the remaining useful performance of analog circuits. Through the successive refinement of the circuit's response to a sweep signal, features are extracted for fault diagnosis. The fault diagnostics problem is posed and solved as a pattern recognition problem using kernel methods. From the extracted features, a fault indicator (FI) is developed for failure prognosis. Furthermore, an empirical model is developed based on the degradation trend exhibited by the FI. A particle filtering approach is used for model adaptation and RUP estimation. This method is completely automated and has the merit of implementation simplicity. Case studies on two analog filter circuits demonstrating this method are presented. © 1982-2012 IEEE.

Chen L.,Hong Kong Baptist University | Zeng W.,Hong Kong Baptist University | Zeng W.,University of Electronic Science and Technology of China
Expert Systems with Applications | Year: 2013

Up to now, more and more online sites have started to allow their users to build the social relationships. Take the Last.fm for example (which is a popular music-sharing site), users can not only add each other as friends, but also join online interest groups where they shall meet people with common tastes. Therefore, in this environment, users might be interested in not only receiving item recommendations (such as music), but also getting friend suggestions so they might put them in the contact list, and group recommendations that they could consider joining. To support such demanding needs, in this paper, we propose a unified framework that provides three different types of recommendation in a single system: recommending items, recommending groups and recommending friends. For each type of recommendation, we in depth investigate the contribution of fusing other two auxiliary information resources (e.g.; fusing friendship and membership for recommending items, and fusing user-item preferences and friendship for recommending groups) for boosting the algorithm performance. More notably, the algorithms were developed based on the matrix factorization framework in order to achieve the ideal efficiency as well as accuracy. We performed experiments with two large-scale real-world data sets that contain users' implicit interaction with items. The results revealed the effective fusion mechanism for each type of recommendation in such implicit data condition. Moreover, it demonstrates the respective merits of regularization model and factorization model: the factorization is more suitable for fusing bipartite data (such as membership and user-item preferences), while the regularization model better suits one mode data (like friendship). We further enhanced the friendship's regularization by integrating the similarity measure, which was experimentally proven with positive effect. © 2013 Elsevier B.V. All rights reserved.

Guo D.,University of Electronic Science and Technology of China | Li C.,Zhejiang University
IEEE Transactions on Neural Networks | Year: 2010

In this paper, we study the self-sustained irregular firing activity in 2-D small-world (SW) neural networks consisting of both excitatory and inhibitory neurons by computational modeling. For a proper proportion of unidirectional shortcuts, the stable self-sustained activity with irregular firing states indeed occurs in the considered network. By varying the shortcut density while keeping other system parameters fixed, different levels of irregular firing states, from weakly irregular to Poisson-like and burst firing states, are obtained in 2-D SW neural networks. It is also observed that this activity is sensitive to small perturbations, which might provide a possible mechanism for producing chaos. On the other hand, we find that several other system parameters, such as the network size and refractory period, have significant impact on this activity. Further simulation results show that the 2-D SW neural network can sustain such long-lasting firing behavior by using a smaller number of connections than the random neural network. © 2006 IEEE.

Song K.,University of Electronic Science and Technology of China | Xue Q.,City University of Hong Kong
IEEE Transactions on Industrial Electronics | Year: 2013

A novel ultrawideband (UWB) ring-cavity multiple-way parallel power divider is presented in this paper. The approximated equivalent-circuit model of the power-dividing unit is presented to analyze its structural parameters and electrical performance. The overall circuit model of the proposed power divider is also given. To verify its potential to accommodate large numbers of power-dividing ports, a UWB 32-way ring-cavity power divider is developed with reasonable agreement between the simulated and measured results. The measured return loss is greater than 10 dB over the entire UWB and also greater than 15 dB from 4.2 to 9.2 GHz. The average insertion loss, amplitude imbalance, phase imbalance, and group delay are around 15.4 dB (including the 15-dB power-dividing insertion loss), ±0.7 dB, ±5° , and 0.85 ns, respectively, across the UWB. In addition, the isolations between the output ports are greater than 10 dB over the UWB except for those between the adjacent output ports. © 1982-2012 IEEE.

Han T.,National University of Singapore | Han T.,University of Electronic Science and Technology of China | Qiu C.-W.,National University of Singapore
Optics Express | Year: 2010

We propose a novel kind of trapeziform cloak requiring only homogeneous anisotropic materials. Large-scale flat cloaks can be degenerated from the general trapeziform cloak with PEC inner boundary, and be realized by isotropic nonmagnetic materials for optical frequencies with controlled index profiles and improved invisibility. With the support of PEC inner boundary, large vehicles and objects of arbitrary shape can be concealed between the PEC and ground, and PEC can be firm by adding pillars in the cloaking space. Full-wave simulations validate the proposed cloaking concept, which is not only based on simple isotropic nonmagnetic materials but also realizable in practice. © 2010 Optical Society of America.

Ren X.,University of Electronic Science and Technology of China
Journal of Materials Science: Materials in Electronics | Year: 2014

CdWO4 particles were synthesized by a hydrothermal process with or without surfactant. The particles have a pure monoclinic phase with the wolframite structure. CdWO4 particles show different morphologies with the assistant of different surfactants. Nanoparticles were obtained when there is no the addition of surfactant. Cetyltrimethyl ammonium bromide and sodium dodecyl benzenesulfonate play the key roles in the formation of nanorods and microspheres, respectively. CdWO4 particles with different morphologies have an emission peak in the blue wavelength range. The emission intensity of microspheres is higher than that of nanoparticles and nanorods. The results show that cetyltrimethyl ammonium bromide and sodium dodecyl benzenesulfonate alter the shape and size of resulting CdWO4 crystals. © 2014, Springer Science+Business Media New York.

Li J.,University of Sydney | Li J.,University of Electronic Science and Technology of China | Hudson D.D.,University of Sydney | Jackson S.D.,University of Sydney
Optics Letters | Year: 2011

A high-power diode-cladding-pumped Ho3+-doped fluoride glass fiber laser operating in cascade mode is demonstrated. The 5I 6→5I7 and 5I 7→5I8 laser transitions produced 0:77W at a measured slope efficiency of 12.4% and 0:24Wat a measured slope efficiency of 5.2%, respectively. Using a long fiber length, which forced a large threshold for the 5I7→5I8 transition, a wavelength of 3:002 μm was measured at maximum output power, making this system the first watt-level fiber laser operating in the mid-IR. © 2011 Optical Society of America.

Dutta B.,Texas A&M University | Gao Y.,Texas A&M University | Ghosh T.,Texas A&M University | Gogoladze I.,University of Delaware | And 2 more authors.
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2016

We consider the diphoton resonance at the 13 TeV LHC in a consistent model with new scalars and vector-like fermions added to the Standard Model, which can be constructed from orbifold grand unified theories and string models. The gauge coupling unification can be achieved, neutrino masses can be generated radiatively, and the electroweak vacuum stability problem can be solved. To explain the diphoton resonance, we study a spin-0 particle, and discuss various associated final states. We also constrain the couplings and number of the introduced heavy multiplets for the new resonance's width at 5 or 40 GeV. © 2016 American Physical Society.

Wu X.-J.,University of Electronic Science and Technology of China | Zhu X.-J.,Shanghai JiaoTong University
International Journal of Energy Research | Year: 2013

For a solid oxide fuel cell (SOFC) and micro gas turbine (MGT) hybrid system, optimal control of load changes requires optimal dynamic scheduling of set points for the system's controllers. Thus, this paper proposes an improved iterative particle swarm optimization (PSO) algorithm to optimize the operating parameters under various loads. This method combines the iteration method and the PSO algorithm together, which can execute the discrete PSO iteratively until the control profile would converge to an optimal one. In MATLAB environment, the simulation results show that the SOFC/MGT hybrid model with the optimized parameters can effectively track the output power with high efficiency. Hence, the improved iterative PSO algorithm can be helpful for system analysis, optimization design, and real-time control of the SOFC/MGT hybrid system. © 2011 John Wiley & Sons, Ltd.

Li Q.,Sichuan Electric Power Research Institute | Zhou M.,University of Electronic Science and Technology of China
Journal of Computers | Year: 2011

Since its emergence, smart grid has been given increasingly widespread attentions. Basically, smart grid combines a various modern technologies like network communication, information processing and distributed control to provide a more secure, reliable and intelligent grid, thus meeting the requirements of future social and economic development. As a new paradigm in the power grid, smart grid undoubtedly represents the mainstream trend of future electric industry. As a result, it also brings some new technical challenges to researchers and engineering practioners. To support researchers and engineering practioners constructing a modern and intelligent grid, research in the field of smart grid has proliferated. In this paper, we look deeper into some key issues of smart grid, such as distributed cooperation and control, data and application integration, and knowledgebased comprehensive decision. Still, we give some solutions to resolve these challenges. In addition, we also introduce the concept of smart grid and define its key characteristics. Finally, we outline future directions of research and conclude the paper. © 2011 ACADEMY PUBLISHER.

Li S.-Y.R.,Chinese University of Hong Kong | Tan X.J.,University of Electronic Science and Technology of China
IEEE Transactions on Information Theory | Year: 2011

This paper considers a packet multiplexer (resp. demultiplexer) in the form of a queue with a single time-multiplexed input (resp. output) line, which is called a multiplexing queue (resp. demultiplexing queue). This queue is abstractly formulated in a way that allows recursive construction via 2-stage interconnection. The theoretic underpinning of this recursive construction is the preservation of two types of conditionally nonblocking switches through two versions of the 2-stage interconnection network. The recursive construction of a mux/demux queue emulates such switch preservation into a serial connection of fiber-switch blocks, which combine optical switches with fiber delay lines. Moreover, appropriate tandem connection between these two devices makes a FIFO queue. In terms of the physical structure, an instance of the FIFO queue so constructed coincides with the existing construction in the literature. The switching control mechanisms are different though. Inheriting the unique-routing characteristic of the 2-stage interconnection network, the present construction is under faster control, which distributes the computation task to individual blocks. © 2011 IEEE.

Hu J.,University of Electronic Science and Technology of China | Feng G.,City University of Hong Kong
Asian Journal of Control | Year: 2011

This paper presents a study of a tracking control problem for a multiagent system with an active leader and quantized communication constraints. We first design a discrete-time distributed estimator-based tracking control for each follower-agent and analyze the tracking convergence with the help of the Riccati equation and common Lyapunov function when the communication channel is perfect and the interconnection topology is time-varying. Then a stochastic quantization strategy is applied to model the information communication in the agent coordination and the corresponding solution to the tracking control problem is also given. Finally, a numerical example is given to illustrate the tracking control algorithm. © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society.

Qian S.,University of Electronic Science and Technology of China | Sheng Y.,Anhui University of Science and Technology
Annals of Biomedical Engineering | Year: 2011

Photogrammetry has become an effective method for the determination of electroencephalography (EEG) electrode positions in three dimensions (3D). Capturing multi-angle images of the electrodes on the head is a fundamental objective in the design of photogrammetry system for EEG localization. Methods in previous studies are all based on the use of either a rotating camera or multiple cameras, which are time-consuming or not cost-effective. This study aims to present a novel photogrammetry system that can realize simultaneous acquisition of multi-angle head images in a single camera position. Aligning two planar mirrors with the angle of 51.4°, seven views of the head with 25 electrodes are captured simultaneously by the digital camera placed in front of them. A complete set of algorithms for electrode recognition, matching, and 3D reconstruction is developed. It is found that the elapsed time of the whole localization procedure is about 3 min, and camera calibration computation takes about 1 min, after the measurement of calibration points. The positioning accuracy with the maximum error of 1.19 mm is acceptable. Experimental results demonstrate that the proposed system provides a fast and cost-effective method for the EEG positioning. © 2011 Biomedical Engineering Society.

Wei G.,CAS Institute of Psychology | Zhang Y.,University of Electronic Science and Technology of China | Zhang Y.,CAS Institute of Automation | Jiang T.,CAS Institute of Automation | Luo J.,CAS Institute of Psychology
PLoS ONE | Year: 2011

Sports experts represent a population of people who have acquired expertise in sports training and competition. Recently, the number of studies on sports experts has increased; however, neuroanatomical changes following extensive training are not fully understood. In this study, we used cortical thickness measurement to investigate the brain anatomical characteristics of professional divers with extensive training experience. A comparison of the brain anatomical characteristics of the non-athlete group with those of the athlete group revealed three regions with significantly increased cortical thickness in the athlete group. These regions included the left superior temporal sulcus, the right orbitofrontal cortex and the right parahippocampal gyrus. Moreover, a significant positive correlation between the mean cortical thickness of the right parahippocampal gyrus and the training experience was detected, which might indicate the effect of extensive training on diving players' brain structure. © 2011 Wei et al.

Chen M.,Nanjing University of Aeronautics and Astronautics | Ge S.S.,National University of Singapore | Ge S.S.,University of Electronic Science and Technology of China
IEEE Transactions on Industrial Electronics | Year: 2015

In this paper, an adaptive neural output feedback control scheme is proposed for uncertain nonlinear systems that are subject to unknown hysteresis, external disturbances, and unmeasured states. To deal with the unknown nonlinear function term in the uncertain nonlinear system, the approximation capability of the radial basis function neural network (RBFNN) is employed. Using the approximation output of the RBFNN, the state observer and the nonlinear disturbance observer (NDO) are developed to estimate unmeasured states and unknown compounded disturbances, respectively. Based on the RBFNN, the developed NDO, and the state observer, the adaptive neural output feedback control is proposed for uncertain nonlinear systems using the backstepping technique. The first-order sliding-mode differentiator is employed to avoid the tedious analytic computation and the problem of "explosion of complexity" in the conventional backstepping method. The stability of the whole closed-loop system is rigorously proved via the Lyapunov analysis method, and the satisfactory tracking performance is guaranteed under the integrated effect of unknown hysteresis, unmeasured states, and unknown external disturbances. Simulation results of an example are presented to illustrate the effectiveness of the proposed adaptive neural output feedback control scheme for uncertain nonlinear systems. © 1982-2012 IEEE.

Lin H.,University of Electronic Science and Technology of China | Chen W.,Hebei United University
Journal of Microbiological Methods | Year: 2011

The thermostability of proteins is particularly relevant for enzyme engineering. Developing a computational method to identify mesophilic proteins would be helpful for protein engineering and design. In this work, we developed support vector machine based method to predict thermophilic proteins using the information of amino acid distribution and selected amino acid pairs. A reliable benchmark dataset including 915 thermophilic proteins and 793 non-thermophilic proteins was constructed for training and testing the proposed models. Results showed that 93.8% thermophilic proteins and 92.7% non-thermophilic proteins could be correctly predicted by using jackknife cross-validation. High predictive successful rate exhibits that this model can be applied for designing stable proteins. © 2010 Elsevier B.V.

Wan M.,University of Electronic Science and Technology of China
Journal of Information and Computational Science | Year: 2011

Dynamical properties of a blind decorrelation neural network are investigated by analyzing the corresponding Deterministic Discrete Time (DDT) system. Invariant sets of this neural network are obtained so that the non-divergence of the trajectories can be guaranteed. In the invariant sets, the conditions for convergence and chaos are derived respectively. Based on the convergence result, an online version of the DDT system is given. Simulations verify the obtained results. Copyright © 2011 Binary Information Press.

Zhu Q.,University of Electronic Science and Technology of China
Proceedings of the 8th International Conference on Advanced Computational Intelligence, ICACI 2016 | Year: 2016

Spatial data mining is a new research direction in the field of Data Mining. In recent years, with the continuous development of data mining technology, spatial data attracts more and more attentions of scholars and experts. Spatial clustering analysis is an important part of spatial data mining. Nowadays, spatial clustering analysis has become more and more mature, widely used in various fields. Spatial clustering analysis algorithm can deeply discover the knowledge which hidden in the geospatial information, find out the representative node of one or a number of spatial data collection, discovery the law of the spatial distribution. Classic clustering algorithm basing on partition widely used in the field of cities planning and provide valuable reference. This paper is based on the spatial data mining method, analysis and optimize the spatial data clustering algorithm in the Location Problem in the city, providing scientific location decisions. © 2016 IEEE.

Wu X.-J.,University of Electronic Science and Technology of China | Zhu X.-J.,Shanghai JiaoTong University
Journal of Power Sources | Year: 2011

Solid oxide fuel cell and micro gas turbine (SOFC/MGT) hybrid system is a promising distributed power technology. In order to ensure the system safe operation as well as long lifetime of the fuel cell, an effective control manner is expected to regulate the temperature and fuel utilization at the desired level, and track the desired power output. Thus, a multi-loop control strategy for the hybrid system is investigated in this paper. A mathematical model for the SOFC/MGT hybrid system is built firstly. Based on the mathematical model, control cycles are introduced and their design is discussed. Part load operation condition is employed to investigate the control strategies for the system. The dynamic modeling and control implementation are realized in the MATLAB/SIMULINK environment, and the simulation results show that it is feasible to build the multi-loop control methods for the SOFC/MGT hybrid system with regard to load disturbances. © 2011 Elsevier B.V. All rights reserved.

Wang W.-Q.,University of Electronic Science and Technology of China
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2013

Large-area mapping is of great valuable in microwave remote sensing, but it is a contradiction between swath width and azimuth resolution due to the minimum antenna area constraint. In this paper, we consider a specific wide-area mapping technique with high-altitude high-speed platform, where range ambiguity suppression is a technical challenge. To resolve this problem, we present a multiple-input multiple-output (MIMO) synthetic aperture radar (SAR) with multiple antennas placed in the cross-track direction. The increased degrees-of-freedom (DOFs) provide a potential to resolve possible range and/or azimuth ambiguities. After formalizing the system scheme and signal model, an iterative matched filtering algorithm is presented, which can efficiently suppress the cross-correlation interferences in the multichannel data separation. Furthermore, a range-Doppler based image formation algorithm is derived. The MIMO SAR system performance is evaluated by the range-ambiguity-to-signal ratio (RASR) performance. Numerical simulation results validate the effectiveness of the proposed MIMO SAR in high-altitude high-speed platform SAR for large-area remote sensing. © 2008-2012 IEEE.

Zhang W.,University of Electronic Science and Technology of China | Poor H.V.,Princeton University
IEEE Transactions on Information Theory | Year: 2011

The problem of detecting a wide-sense stationary Gaussian signal process embedded in white Gaussian noise, in which the power spectral density of the signal process exhibits uncertainty, is investigated. The performance of minimax robust detection is characterized by the exponential decay rate of the miss probability under a Neyman-Pearson criterion with a fixed false alarm probability, as the length of the observation interval grows without bound. A stochastic suppression condition is identified for the uncertainty set of spectral density functions, and it is established that, under the stochastic suppression condition, the resulting minimax problem possesses a saddle point, which is achievable by the likelihood ratio tests matched to a so-called suppressing power spectral density in the uncertainty set. No convexity condition on the uncertainty set is required to establish this result. © 2011 IEEE.

Zhang W.,University of Electronic Science and Technology of China | Vedantam S.,Bloomberg LP | Mitra U.,University of Southern California
IEEE Transactions on Information Theory | Year: 2011

A scenario involving a source, a channel, and a destination, where the destination is interested in both reliably reconstructing the message transmitted by the source and estimating with a fidelity criterion the state of the channel, is considered. The source knows the channel statistics but is oblivious to the actual channel state realization. Herein, it is established that a distortion constraint for channel state estimation can be reduced to an additional cost constraint on the source input distribution, in the limit of large coding block length. A newly defined capacity-distortion function thus characterizes the fundamental tradeoff between transmission rate and state estimation distortion. It is also shown that noncoherent communication coupled with channel state estimation conditioned on treating the decoded message as training symbols achieves the capacity-distortion function. Among the various examples considered, the capacity-distortion function for a memoryless Rayleigh fading channel is characterized to within 1.443 bits at high signal-to-noise ratio. The constrained channel coding approach is also extended to multiple access channels, leading to a coupled cost constraint on the input distributions for the transmitting sources. © 2011 IEEE.

Wang W.-Q.,University of Electronic Science and Technology of China
IEEE Transactions on Geoscience and Remote Sensing | Year: 2015

Multiple-input multiple-output (MIMO) synthetic aperture radar (SAR) has received much attention due to its interesting application potentials, but effective waveform diversity design is still a technical challenge. In a MIMO SAR, each antenna should transmit a unique waveform, orthogonal to the waveforms transmitted by other antennas. The waveforms should have a large time-bandwidth product, low cross-correlation interferences, and a low peak-average ratio. To reach these aims, this paper proposes an orthogonal frequency division multiplexing (OFDM) chirp waveform with random matrix modulation. The designed waveforms are time-delay and frequency-shift decorrelated. Referring to MIMO SAR high-resolution imaging, the proposed OFDM chirp waveform parameters are optimally designed, and their performances are analyzed through the ambiguity function and range-Doppler-based MIMO SAR imaging algorithm. Extensive and comparative simulation results show that the waveforms have the superiorities of high range resolution, constant time domain and almost constant frequency-domain modulus, large time-bandwidth product, low peak-average ratio, and low time-delay and frequency-shift correlation peaks. More importantly, this scheme can easily generate over three orthogonal waveforms with a large time-bandwidth product. © 1980-2012 IEEE.

Das K.,Harish Chandra Research Institute | Li T.,CAS Institute of Theoretical Physics | Li T.,University of Electronic Science and Technology of China | Nandi S.,Oklahoma State University | Rai S.K.,Harish Chandra Research Institute
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2016

The resonant excesses around 2 TeV reported by the ATLAS Collaboration can be explained in the left-right model, and the tight constraints from lepton plus missing energy searches can be evaded if the SU(2)R gauge symmetry is leptophobic. We, for the first time, propose an anomaly- free leptophobic left-right model with gauge symmetry SU(3)C×SU(2)L×SU(2)R×U(1)X, where the SM leptons are singlets under SU(2)R. The gauge anomalies are cancelled by introducing extra vectorlike quarks. The mass of the Z′ gauge boson, which cannot be leptophobic, is assumed to be around or above 2.5 TeV so that the constraint on the dilepton final state can be avoided. Moreover, we find that the W′→WZ channel cannot explain the ATLAS diboson excess due to the tension with the constraint on the W′→jj decay mode. We solve this problem by considering the mixings between the SM quarks and vectorlike quarks. We show explicitly that the ATLAS diboson excess can be explained in the viable parameter space of our model, which is consistent with all the current experimental constraints. © 2016 American Physical Society.

Mi W.,University of Electronic Science and Technology of China | Qian T.,University of Macau
Automatica | Year: 2014

In this paper, we present an algorithm for estimating poles of linear time-invariant systems by using the backward shift operator. We prove that poles of rational functions, including zeros and multiplicities, are solutions to an algebraic equation which can be obtained by taking backward shift operator to the shifted Cauchy kernels in the unit disc case. The algorithm is accordingly developed for frequency-domain identification. We also prove the robustness of this algorithm. Some illustrative examples are presented to show the efficiency in systems with distinguished and multiple poles. © 2014 Elsevier Ltd. All rights reserved.

Qi J.,Northwestern University | Qi J.,University of Electronic Science and Technology of China
Journal of Microscopy | Year: 2014

With the rapid advancement of 3D confocal imaging technology, more and more 3D cellular images will be available. However, robust and automatic extraction of nuclei shape may be hindered by a highly cluttered environment, as for example, in fly eye tissues. In this paper, we present a novel and efficient nuclei segmentation algorithm based on the combination of graph cut and convex shape assumption. The main characteristic of the algorithm is that it segments nuclei foreground using a graph-cut algorithm with our proposed new initialization method and splits overlapping or touching cell nuclei by simple convexity and concavity analysis. Experimental results show that the proposed algorithm can segment complicated nuclei clumps effectively in our fluorescent fruit fly eye images. Evaluation on a public hand-labelled 2D benchmark demonstrates substantial quantitative improvement over other methods. For example, the proposed method achieves a 3.2 Hausdorff distance decrease and a 1.8 decrease in the merged nuclei error per slice. © 2013 The Author.