Time filter

Source Type

Shenyang, China

Northeastern University is a public university in the city of Shenyang, Liaoning Province, China. With an annual enrollment of over 20,000 students, it is one of China's high level universities designated for the state key construction of the 211 Project and 985 Project. Wikipedia.

Hao A.,Northeastern University China | Zhu Y.,Yanshan University
Journal of Applied Physics | Year: 2012

We investigate the phase transition, elastic constants, and phonon dispersion curves of beryllium at high pressure using density functional theory. By comparing the Gibbs free energy, in the quasiharmonic approximation, of hexagonal-closed-packed (hcp, α) with those of body-centered-cubic (bcc, β), we find that α phase is stable up to 320 GPa, and then transforms to β phase. We further investigate high-pressure elastic behavior of α-Be by computing the second-order elastic constants and their variation with pressure. Using Born conditions of mechanical stability at high pressure, we confirm that α-Be structure is an unstable phase at 320 GPa. The phonon dispersion curves of α-Be under high pressure up to 320 GPa do not show any imaginary frequencies. Contrarily to α phase, β-Be phonon dispersion curves show anomalous features at zero pressure. The imaginary frequencies become real ones as pressure increases up to 320 GPa, indicating that β-Be becomes one mechanical stability structure at this pressure. © 2012 American Institute of Physics.

Che W.-W.,Nanyang Technological University | Wang J.-L.,Nanyang Technological University | Yang G.-H.,Northeastern University China
IET Control Theory and Applications | Year: 2010

This study is concerned with the quantised H∞ filtering problem for discrete-time systems subject to limited communication capacity, which includes measurement quantisation and random sensor packet losses. By introducing an improved quantised random packet-loss model, the effects of the packet-loss rate and the upper bound of consecutive packet losses and the quantisation on the system performance are considered simultaneously. A quantised H∞ filter design strategy with the minimised static quantiser range is designed to guarantee the error system exponentially mean-square stable and also achieve the prescribed H∞ disturbance attenuation level. A numerical example is given to illustrate the effectiveness of the proposed filter design method. © 2010 The Institution of Engineering and Technology.

Guo Y.,Northeastern University China
Journal of Mathematical Imaging and Vision | Year: 2014

The vanishing line is useful information for recovering affine properties of the plane in computer vision. This paper describes how to determine analytically the vanishing line from a single perspective view of a plane containing the four points of known normalized barycentric coordinates in a general position, and further how to compute the vanishing line via the eigenvector representation. We also propose that the projectivity may be expressed directly and analytically from the vanishing line and three 3D-2D point correspondences. It is shown that plane affine properties may be computed and the metric may be recovered from known metric information, which includes an angle, two equal but unknown angles, and a length ratio of two non-parallel line segments, without using the image of the circular points as an intermediate step. The correctness and performance of the novel results are demonstrated by thorough testing on both synthetic and real data. © 2014 Springer Science+Business Media New York.

Wang J.,Northeastern University China
Nonlinear Dynamics | Year: 2012

To prevent or mitigate the cascading propagation on complex networks more efficiently, taking into account some existing protections and measures in real-life networks, we introduce a new mitigation strategy. Applying the global removal and two attacking strategies, we demonstrate the efficiency of the mitigation method on improving the robustness level against cascading failures in Barabási-Albert (BA) scale-free networks and in the Internet, as well as in the power grid of the western United States. We show that only making simple adjustments to the overload edges can dramatically enhance the robustness of diverse networks subject to the global removal and targeted attacks.We further compare the mitigation strategy in two attacks and observe to what extent the improvement of the robustness in two attacks depends on the parameters in our cascading model. In addition, by the times that an edge overloads in the cascading propagation, we discuss how to protect the edges with the different load. Our results are useful not only for improving significantly the robustness of complex networks but also for further studying on the control and defense of cascading failures. © Springer Science+Business Media B.V. 2012.

Wang C.,Northeastern University China
Enterprise Information Systems | Year: 2016

Rapidly processing raw data and effectively extracting underlining information from huge volumes of multivariate data become essential to all decision-making processes in sectors like finance, government, medical care, climate analysis, industries, science, etc. Remarkably, visualisation is recognised as a fundamental technology that props up human comprehension, cognition and utilisation of burgeoning amounts of heterogeneous data. This paper presents a computational visualisation system, named DataView, which has been developed for graphically displaying and capturing outcomes of multiphysics problem-solvers widely used in engineering fields. The DataView is functionally composed of techniques for table/diagram representation, and graphical illustration of scalar, vector and tensor fields. The field visualisation techniques are implemented on the basis of a range of linear and non-linear meshes, which flexibly adapts to disparate data representation schemas adopted by a variety of disciplinary problem-solvers. The visualisation system has been successfully applied to a number of engineering problems, of which some illustrations are presented to demonstrate effectiveness of the visualisation techniques. © 2014 Taylor & Francis.

Chen Z.,South China Normal University | Yang S.,South China Normal University | Wang Y.,Northeastern University China | Xing D.,South China Normal University
Optics Letters | Year: 2015

An all-optically noncontact dual-mode imaging system using a single Michelson detector that simultaneously achieved photo-acoustic microscopy (PAM) and optical coherence tomography (OCT) is presented. The pulse laser-induced photo-acoustic signals and the back-scattered photons were alternately detected by a single Michelson detector. The spatial resolution and imaging capability of the dual-mode imaging system were testified by scattering phantoms. Furthermore, in vivo images of the mouse ear demonstrated that the PAM-OCT can provide complementary anatomical and functional information for imaging of biological tissues, which could be the best co-imaging strategy of PAM and OCT in biomedicine. © 2015 Optical Society of America.

Wang D.-W.,Northeastern University China
Xitong Gongcheng Lilun yu Shijian/System Engineering Theory and Practice | Year: 2011

Due to untrue advertisements appear in search results, the position auction mechanism with more attention on profit was criticized by public in China. To improve and normalize keyword search auction, we recommend a new position auction mechanism with consideration on advertiser reputations. Based on classical VCG auction, the winner determination approach is proposed. The computational formulas for all advertising slots are deduced and presented. Comparing with original position auction without reputations, the new mechanism may bring a little of profit loss to the web-search merchants in the same bidding levels of advertisers. However, in view of long-term perspective, the reputation raise of search engine with the new auction mechanism will bring much more daily browsing amounts. It certainly will make great profit to the web-search merchants.

Qian Y.H.,CAS Shenyang Institute of Metal Research | Niu D.,Northeastern University China | Xu J.J.,CAS Shenyang Institute of Metal Research | Li M.S.,CAS Shenyang Institute of Metal Research
Corrosion Science | Year: 2013

To investigate the influence of chromium content on corrosion characteristics of weathering steels, the electrochemical measurements were performed on the steels containing 0-9% Cr (wt.%) in NaHSO3 aqueous solution. The results indicated that the open circuit potential of these steels shifted to the positive direction remarkably, because the additions of Cr improved the passivation capability of the steels. The corrosion current density of the steels containing more than 7% Cr (wt.%) decreased significantly after pre-rusted treatment, implying the corrosion resistance could be enhanced by the formation of protective goethite rust layer. © 2013 Elsevier Ltd.

Zhao X.,Northeastern University China
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2010

The appropriate size and stability of insulating pillar, which are transition stretch shifting from shallow excavation to deep mining, are very important for safe production of deep mine. According to the field engineering condition shifting from shallow excavation to deep mining, the appropriate size of insulating pillar is calculated and analyzed by using methods of limit span mechanism, empirical equation method and limit equilibrium method. The analysis result shows that for guaranteeing the insulating pillar stability the thickness of insulating pillar is 21m. According to insulating pillar with thickness of 21m, original design scheme is revised. FLAC3D is adopted to analyze the stability of revised design scheme, deformation and failure process of insulating pillar during caving. The numerical result shows that when mine is excavated 33m high under insulating pillar, the insulating pillar will lose its strength and fail. Meanwhile, thickness of 28 m overburden layer is safe for non-hollow sublevel caving, which can guarantee the safety of personnel and equipment. It validates the revised insulating pillar thickness and conducts the production, which will supply the empirical method for the similar mine.

Sun L.,Northeastern University China | Gao F.,Guangxi University | Huang Q.,Guangxi University
Journal of Alloys and Compounds | Year: 2014

The upconversion (UC) photoluminescence and ferroelectric properties of Er3+-Tm3+-Yb3+ tri-codoped bismuth titanate (BETYT) thin films were studied. The thin films were prepared by chemical solution deposition method. There are four emission bands in the visible UC luminescence spectra excited by 980 nm at room temperature. The 478 nm blue emission band corresponds to 1G4 → 3H 6 transition of Tm3+, and the 527 nm, 548 nm green emission bands correspond to 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions of Er3+, and the 657 nm red emission band corresponds to 4F9/2 → 4I15/2 transition of Er3+ and 1G4 → 3F4 transition of Tm 3+. The fluorescent color can be tuned by adjusting Er3+, Tm3+ and Yb3+ concentrations and the optimal color coordinate in these films is (0.31, 0.34), very close to the standard white-light coordinate of (0.33, 0.33) when pumped under power intensity about 2.8 W/cm2. The UC emission mechanism was discussed and there exist significant energy transfers from Er3+ to Tm3+, which will affect the relative intensity of blue, green and red emissions and their quenching concentrations. The remanent polarization (2Pr) value of BEr 0.0085TYT thin film prepared on Pt/Ti/SiO2/Si substrate is 27.8 μC/cm2. The combination of UC photoluminescence and ferroelectric properties in BETYT thin films would open the possibility of inventing novel multifunctional optoelectronic integration devices. © 2013 Elsevier B.V. All rights reserved.

Liu W.J.,Northeastern University China
Acta Metallurgica Sinica (English Letters) | Year: 2014

A recently developed advanced hot-formed (AHF) steel for automobile is introduced and three physical metallurgy concepts based on which the AHF steel was designed are reviewed, they are dynamic carbon partitioning (DCP), flash copper precipitation and bake toughening. AHF steel is an upgrade of the existing hot-formed steel especially suitable for making components with superior crashworthiness; it can be processed by regular hot stamping equipment and process. A kinetics model for DCP is expressed in detail, which can be used to calculate the volume fraction of retained austenite based on four materials and processing parameters. The flash copper precipitation used as an additional strengthening mechanism for AHF steel is also discussed and its ultrafast kinetics can be attributed to the enhancement of quenched-in vacancies on copper diffusion. Also, the bake toughening of AHF steel is addressed; the mechanism of which may be related to the elimination of the less stable block-like retained austenite. © The Chinese Society for Metals and Springer-Verlag Berlin Heidelberg 2014.

Si G.,Northeastern University China | Zhao Y.,Pennsylvania State University | Leong E.S.P.,Institute of Materials Research and Engineering of Singapore | Liu Y.J.,Institute of Materials Research and Engineering of Singapore
Materials | Year: 2014

Liquid crystals are a promising candidate for development of active plasmonics due to their large birefringence, low driving threshold, and versatile driving methods. We review recent progress on the interdisciplinary research field of liquid crystal based plasmonics. The research scope of this field is to build the next generation of reconfigurable plasmonic devices by combining liquid crystals with plasmonic nanostructures. Various active plasmonic devices, such as switches, modulators, color filters, absorbers, have been demonstrated. This review is structured to cover active plasmonic devices from two aspects: functionalities and driven methods. We hope this review would provide basic knowledge for a new researcher to get familiar with the field, and serve as a reference for experienced researchers to keep up the current research trends. © 2014 by the authors.

Zhang Y.,Northeastern University China | Yang B.,CAS Shenyang Institute of Metal Research
Journal of Alloys and Compounds | Year: 2014

The magnetic properties and magnetocaloric effect (MCE) in ErNi 2-xFexB2C have been studied. Substitution of Fe for Ni lowered the magnetic transition temperature T M, and reduced the magnetic hysteresis of ErNi2B 2C. An inverse MCE was observed under low magnetic field and at low temperatures, which is attributed to the nature of antiferromagnetic state for the present ErNi2-xFexB2C compounds. A normal MCE was observed under higher magnetic field changes, which is related to a field-induced first order metamagnetic transition from antiferromagnetic to ferromagnetic state. The maximum values of magnetic entropy change -ΔSMmax are 14.5, 12.7, and 10.6 J/kg K with a magnetic field change of 0-70 kOe for x = 0, 0.1, and 0.2 in ErNi 2-xFexB2C, respectively. © 2014 Elsevier B.V. All rights reserved.

Zhang Y.,ShenYang Agricultural University | Zhang Y.,Northeastern University China
Physica D: Nonlinear Phenomena | Year: 2013

We demonstrate strange nonchaotic attractors with Wada basins (SNAsWB), and verify the abundance of SNAsWB in a quasiperiodically forced Holmes map. We identify the routes to the creation of the SNAsWB in a two-parameter space. The SNAsWB are characterized by the maximal Lyapunov exponent, by the estimation of the phase sensitivity exponent, and by the singular-continuous spectra. We observe that the SNAs' basins are totally Wada basins in a large range of parameters. The topological structures of the SNAs' Wada basins are distinguished by the basin cell method. We investigate the underlying mechanism for the abundance of SNAsWB, which is responsible for different types of basin cell in the absence of forcing. This suggests that the SNAs cannot be predicted reliably for specific initial conditions. These SNAsWB can thus be expected to occur more commonly in dynamical systems. © 2013 Elsevier B.V. All rights reserved.

Liu S.,Northeastern University China | Su X.,Jilin University
RSC Advances | Year: 2014

As a novel nanomaterial, I-III-VI type quantum dots have been a major focus of research and development in the past decade, which can be attributed to their tunable fluorescence emission wavelengths, high photostability and low toxicity of chemical composition. In addition, I-III-VI type quantum dots have fluorescence emission wavelengths in the near-infrared regions, and thus have potential applications in bioimaging. In this review, several recent advances regarding I-III-VI type quantum dots are summarized, including synthetic methods, characteristics and some applications. Furthermore, we discuss the prospects and challenges related to this novel type of quantum dots. This journal is © the Partner Organisations 2014.

Zheng S.,Northeastern University China | Davis C.,University of Birmingham | Strangwood M.,University of Birmingham
Materials Characterization | Year: 2014

In this study, elemental segregation during solidification and subsequent precipitation behaviour in a continuous cast Nb-V-Ti high-strength low-alloy steel was investigated by optical microscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy and thermodynamic modelling. It is known that for steels with low carbon contents the pearlite that forms on slow cooling does so where the interdendritic liquid was present prior to final solidification. The alloying elements of Nb, Ti, Mn and V segregate into the interdendritic liquid during solidification, while Al preferentially segregates into the solidifying solid phase. The composition analysis on the slab samples verified the predicted element segregation behaviour, with a smaller difference in the concentrations of Mn and V in the pearlite and dendritic ferrite regions being observed compared to the Nb levels. Small (30-100 nm) spherical or irregular shaped Nb-rich precipitates (Nb(C, N) and (Nb, V)(C, N)) were mainly found in the pearlite regions, while angular Al-rich (60-300 nm) precipitates were found in the dendritic ferrite regions, in the form of AlN and complex AlN-V(C, N) precipitates. Small isolated ferrite regions surrounded by pearlite were observed in the microstructure and has two origins: one type is dendritic ferrite that appears as an isolated island due to a sectioning effect when observing the two-dimensional microstructure; the other is a ferrite idiomorph that forms in the interdendritic region due to the low carbon content of the steel. Accordingly, in these isolated ferrite islands two different precipitation behaviours are found; predominantly Al-rich particles in the dendritic regions or predominantly Nb-rich precipitates in the interdendritic ferrite idiomorphs. No Al-rich precipitates were observed in the interdendritic regions (pearlite or isolated ferrite idiomorphs) despite the Thermo-Calc predictions indicating a higher volume fraction of AlN in these regions compared to the dendritic regions. This is believed to be due to back diffusion of nitrogen after solidification reducing the available nitrogen, which reacts with the high Nb levels present. © 2014 Elsevier Inc.

Wang L.,Northeastern University China
IEEE Electron Device Letters | Year: 2015

To improve the sensitivity of thin eddy current device to measure the gap in small interlayer structure, an object-property-based differential structure is designed. The object-property-based differential eddy current gap sensing device has negative lift-off effect element (NLOEE) and positive lift-off effect element (PLOEE). The object in NLOEE/PLOEE is made of soft-magnetic material/nonmagnetic or hard-magnetic material, which results in a reduction/an increase of the NLOEE/PLOEE coil inductance with the increaese of the lift-off. Through using NLOEE and PLOEE as the neighboring arms of an electrical bridge, the conversion from the lift-off to the voltage is realized. The results show that the sensitivity can be improved using the object-property-based differential structure. © 2014 IEEE.

Zhang L.,Coventry University | Zhang L.,Northeastern University China | Potherat A.,Coventry University
Physics of Fluids | Year: 2013

An analysis of the successive regimes of the two-dimensional (2D) flow through a sharp 180° bend is performed by means of parametric numerical simulations where the Reynolds number Re and the opening ratio β (defined as the ratio of bend opening to the inlet width) vary in the respective ranges [0-2500] and [0.1-10]. In the outlet, the sequence of flow regimes is found to bear similarities with the flow behind a two-dimensional cylinder, despite being asymmetric by nature: when Re was increased, we found a laminar flow, then a flow with a first recirculation attached to the inside boundary, then one with a second recirculation attached to the top boundary. The onset of unsteadiness occurs through instability of the main stream and vortex shedding from the inside boundary. For β ≤ 0.2, the flow is characterised by the dynamics of the jet generated at the very small turning part whereas for β ≥ 0.3, it behaves rather like the flow behind an obstacle placed in a channel. This difference is most noticeable in the unsteady regimes where the vortex shedding mechanisms differ. While the former generates a more turbulent flow rich in small scale turbulence, the latter produces large structures of the size of the channel. In the turning part, further series of recirculation develop in each corner, akin to those identified by Moffatt ["Viscous and resistive eddies near a sharp corner," J. Fluid Mech.18, 1 (1964)10.1017/S0022112064000015]. For β > 1 corresponding eddies merge to form a series of alternately rotating recirculating cells, which occupy the whole width of the turning part. We find that for β > 1, the effective opening ratio β*, which correspond to the area occupied by the mainstream while passing from the inlet to the outlet, tends towards a value of ≃0.7. The combination of regimes in the outlet and the turning part yields a wealth of flow regimes, which open interesting possibilities to tailor the design of 180° bends to suit particular applications involving mixing, heat, and mass transfer. Selected 3D simulations show that with a few noticeable exceptions, 2D dynamics determine the main features of the flow (drag and recirculation length), even in a wide bend, while 3D structure tends to slow down the shedding mechanism. 2D simulations are thus not only relevant to configurations where the flow is expected to be 2D (thin bend, MHD flows), but also to 3D flows where they can predict some of the global flow features at a low computational cost. © 2013 AIP Publishing LLC.

Liu P.,Shenyang University of Technology | Zhou X.,Shenyang University of Technology | Tang L.,Northeastern University China
International Journal of Advanced Manufacturing Technology | Year: 2010

A new scheduling model in which both two-agent and position-dependent processing times exist simultaneously is considered in this paper. Two agents compete to perform their respective jobs on a common single machine, and each agent has his own criterion to optimize. The job position-dependent processing time is characterized by increasing or decreasing function dependent on the position of a job in the sequence. We introduce an aging effect and a learning effect into the two-agent single-machine scheduling, where the objective is to minimize the total completion time of the first agent with the restriction that the maximum cost of the second agent cannot exceed a given upper bound. We propose the optimal properties for the considered scheduling problems and then present the optimal polynomial time algorithms to solve the two scheduling problems, respectively. © Springer-Verlag London Limited 2009.

Wang S.,Northeastern University China | Ni P.,Queens University
International Journal of Computational Methods | Year: 2014

Rock slopes stability has been one of the fundamental issues facing geotechnical engineering researchers. Due to the pre-existing joints, the intactness of the rock is weakened. The mechanical characteristics are changed correspondingly along with joint-induced stress redistribution within the rock mass if the sliding limit at the joint or part of it is exceeded. In this study, spatial block topological identification techniques are applied to distinguish all blocks cut by 3D finite random or fixed discontinuities. Based on the available photographic information of rock slopes, the sliding forces and the corresponding factor of safety are evaluated through limit equilibrium conditions by the classic block theory. The rock slope stability analysis software, GeoSMA-3D (Geotechnical Structure and Model Analysis), satisfying the requirements of spatial block modeling, joint plane simulation, key block identification and analysis and sliding process display, was developed. The application of such a software on the analysis of a rock slope, which is located near the inlet of Daiyuling No. 1 tunnel on the Zhuanghe-Gaizhou highway networks, was performed. The assessed results were compared with the monitored data to validate the effectiveness of such software. © World Scientific Publishing Company.

Novel alloys with high aluminum addition, so-called δ-transformation-induced plasticity (TRIP), have been developed recently for the third generation of advanced high strength steels for automotive applications, which are promising owing to the potential weldability as well as the combination of strength and ductility. In addition, the high aluminum addition results in a density reduction of approximately 5% in these δ-TRIP alloys without sacrificing the Young’s modulus in uniaxial tensile tests. The origin of δ-TRIP concept is introduced first with a review of the published work on δ-TRIP alloys. This review will include methodology for retention of δ-ferrite in casting, rolling and welding conditions, microstructure evolution by austempering, as well as microstructures–properties relationship involving the roles of blocky and lath retained austenite. In addition, currently unresolved problems will be discussed regarding the fundamentals of materials design, automotive application, and industrial manufacturing. © 2014, The Minerals, Metals & Materials Society.

Li J.-Q.,Liaocheng University | Pan Q.-K.,Liaocheng University | Pan Q.-K.,Northeastern University China
International Journal of Production Economics | Year: 2013

This paper proposes a hybrid chemical-reaction optimization (HCRO) algorithm for solving the job-shop scheduling problem with fuzzy processing time. The flexible maintenance activities under both resumable and non-resumable situations are also considered to make the problem more close to the reality. In the proposed algorithm, each solution is represented by a chemical molecule. Four elementary reactions, i.e.; on-wall ineffective collision, inter-molecular ineffective collision, decomposition, and synthesis, are imposed. A well-designed crossover function is introduced in the synthesis and decomposition operators. In order to balance the exploitation and exploration, HCRO divides the evolution phase into two loop bodies: the first loop body contains on-wall ineffective collision and inter-molecular ineffective collision, while the second loop body includes all the four elementary reactions. Tabu search (TS) based local search is embedded in the proposed algorithm to enhance the convergence capability. A novel decoding approach is utilized to schedule each operation, while considering each flexible preventive maintenance activity on each machine. The proposed algorithm is tested on sets of the well-known benchmark instances. Through the analysis of experimental results, the highly effective performance of the proposed HCRO algorithm is shown against three efficient algorithms from the literature, i.e.; SMGA (Sakawa and Mori, 1999), GPSO (Niu et al.; 2008), and RKGA (Zheng et al.; 2010). © 2012 Elsevier B.V.

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.

Lu Z.,Northeastern University China
Jinshu Xuebao/Acta Metallurgica Sinica | Year: 2011

Neutron irradiation can lead to the embrittlement and the shift of ductile-brittle transition temperature (DBTT) of the reactor pressure vessel (RPV) steels, which is the potential threat to the safe operation of reactors. Surveillance program for RPVs, irradiation damage and embrittlement of RPV steels and safe evaluation of RPVs were reviewed in this paper. © Copyright.

Ukwattage N.L.,Monash University | Ranjith P.G.,Monash University | Wang S.H.,Northeastern University China
Energy | Year: 2013

Mineral carbonation of alkaline waste materials is being studied extensively for its potential as a way of reducing the increased level of CO2 in the atmosphere. Carbonation converts CO2 into minerals which are stable over geological time scales. This process occurs naturally but slowly, and needs to be accelerated to offset the present rate of emissions from power plants and other emission sources. The present study attempts to identify the potential of coal fly ash as a source for carbon storage (sequestration) through ex-situ accelerated mineral carbonation. In the study, two operational parameters that could affect the reaction process were tested to investigate their effect on mineralization. Coal fly ash was mixed with water to different water-to-solid ratios and samples were carbonated in a pressure vessel at different initial CO2 pressures. Temperature was kept constant at 40 °C. According to the results, one ton of Hazelwood fly ash could sequester 7.66 kg of CO2. The pressure of CO2 inside the vessel has an effect on the rate of CO2 uptake and the water-to-solid ratio affects the weight gain after the carbonation of fly ash. The results confirm the possibility of the manipulation of process parameters in enhancing the carbonation reaction. © 2013 Elsevier Ltd.

Li G.,Northeastern University China | Wang Y.,China Institute of Technology
Journal of Information and Computational Science | Year: 2013

In wireless sensor networks, the communication cost is often several orders of magnitude higher than that of computation. Data aggregation is an essential technique to reduce the communication cost and prolong network lifetime. As wireless sensor networks are usually deployed in unattended or even hostile circumstances to collect sensitive information, sensor nodes are prone to node compromise attacks. Therefore, security should be considered for data aggregation schemes where high data reliability and high data accuracy are both required. We propose a spatial correlation based secure data aggregation scheme which combines abnormal behaviors detection with data aggregation in this paper. It can detect and exclude the exceptional data values within the cluster in order to reduce the influence of malicious attacks and abnormal transmission errors. We show through experiments that our proposed scheme can provide high detection accuracy ratio and low false alarm ratio. © 2013 by Binary Information Press.

Jia N.,Northeastern University China | Jia N.,Max Planck Institute Fur Eisenforschung | Roters F.,Max Planck Institute Fur Eisenforschung | Eisenlohr P.,Max Planck Institute Fur Eisenforschung | And 2 more authors.
Acta Materialia | Year: 2012

We present crystal plasticity finite element simulations of the texture evolution in α-brass polycrystals under plane strain compression. The novelty is a non-crystallographic shear band mechanism [Anand L, Su C. J Mech Phys Solids 2005;53:1362] that is incorporated into the constitutive model in addition to dislocation and twinning. Non-crystallographic deformation associated with shear banding leads to weaker copper and S texture components and to a stronger brass texture compared to simulations enabling slip and twinning only. The lattice rotation rates are reduced when shear banding occurs. This effect leads to a weaker copper component. Also, the initiation of shear banding promotes brass-type components. In summary the occurrence of non-crystallographic deformation through shear bands shifts face-centered-cubic deformation textures from the copper type to the brass type. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Krivilyov M.,Udmurt State University | Volkmann T.,German Aerospace Center | Gao J.,Northeastern University China | Fransaer J.,Catholic University of Leuven
Acta Materialia | Year: 2012

Rapid solidification of stoichiometric Nd2Fe14B alloy in drop tube processing (DTP) is studied experimentally and theoretically. All relevant physical processes, including fluid flow, heat transfer, nucleation and crystal growth, are modeled at different scales. Transient nucleation is described using an extension of the classical nucleation model in terms of Poisson statistics and accounting for the geometrical factors of heterogeneous nuclei. Analysis of phase selection allows prediction of the appropriate processing conditions to optimize the magnetic properties of the as-solidified Nd-Fe-B samples by reducing the amount of α-Fe that forms during solidification. Comparison with experimental microstructural data confirms the modeling results. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Chai T.-Y.,Northeastern University China
Zidonghua Xuebao/Acta Automatica Sinica | Year: 2013

Process control should ensure not only controlled variables to follow their setpoint values, but also the whole process plant to meet operational requirements optimally (e.g., quality, efficiency and consumptions). Process control should also enable operational indices for quality to and efficiency to be improved continuously, while keeping the indices related to consumptions at the lowest possible level. This paper starts with a survey on the existing operational optimization and control methodologies and then presents a data-driven hybrid intelligent optimal operational control for complex industrial processes where process operational models are difficult to obtain. Applications via a hybrid simulation system and an industrial grinding process for hematite ore mineral processing are presented to demonstrate the effectiveness of the proposed operational control method. Issues for future research on the optimal operational control for complex industrial processes are outlined before concluding the paper. Copyright © 2013 Acta Automatica Sinica. All rights reserved.

Yu F.,Shenyang Aerospace University | Zhang J.-F.,Northeastern University China
Communications in Theoretical Physics | Year: 2013

We apply the statefinder diagnostic to the extended holographic Ricci dark energy (ERDE) model without and with interaction to study their behaviors. We plot the trajectories of various parameters for different cases. It is shown that the non-interacting model does not reach the LCDM point {1, 0} and the interacting one is favored, because the interaction makes the evolution of the statefinder pair {r, s} quite different. © 2013 Chinese Physical Society and IOP Publishing Ltd.

Shen Z.,Wuhan University | Tong Q.,Northeastern University China
ICSPS 2010 - Proceedings of the 2010 2nd International Conference on Signal Processing Systems | Year: 2010

Cloud computing provides people the way to share distributed resources and services that belong to different organizations or sites. Since cloud computing share distributed resources via the network in the open environment, thus it makes security problems important for us to develop the cloud computing application. In this paper, we pay attention to the security requirements in cloud computing environment. We proposed a method to build a trusted computing environment for cloud computing system by integrating the trusted computing platform into cloud computing system. We propose a model system in which cloud computing system is combined with trusted computing platform with trusted platform module. In this model, some important security services, including authentication, confidentiality and integrity, are provided in cloud computing system. © 2010 IEEE.

Sun X.,Michigan Technological University | Hwang J.-Y.,Michigan Technological University | Xie S.,Northeastern University China
Fuel | Year: 2011

Adsorption of elemental mercury on various surfactants was calculated by the DFT/B3LYP method. Mulliken charge analysis was employed to reveal the interaction mechanisms. The results showed that uncharged surfactants have negligible ability to attract mercury, while ionized surfactants presented much stronger interactions. Charge analysis showed that oxidized mercury received significant electrons transferred from the functional groups of the surfactants. A mechanism has been proposed that ionization of these surfactants is required to have significant adsorption of mercury, as supported by experimental observations. © 2010 Elsevier Ltd. All rights reserved.

Zhang R.,Northeastern University China | Yun W.Y.,Pusan National University | Moon I.K.,Pusan National University
International Journal of Production Economics | Year: 2011

This paper investigates the problem faced by firms that transport containers by truck in an environment with resource constraints. The considered area is export-dominant. As a result, there are three types of container movements as inbound full, outbound full, and inbound empty movements. Both the time windows at the terminal and at the customers' places and the operation times are considered. Empty containers are also regarded as separate transportation resources besides trucks. The total operating time including waiting time of all the trucks in operation is minimized. The problem is first formulated as a directed graph and then mathematically modeled based on the graph. It falls into a multiple traveling salesman problem with time windows (m-TSPTW) with resource constraints. An algorithm based on reactive tabu search (RTS) is developed to solve the problem. A number of randomly generated examples indicate that the algorithm can be applied to the real world. © 2010 Elsevier B.V. All rights reserved.

Hao L.,CAS Shenyang Institute of Metal Research | Zhang S.,Northeastern University China | Zhang S.,Laiwu Steel Group | Dong J.,CAS Shenyang Institute of Metal Research | Ke W.,CAS Shenyang Institute of Metal Research
Corrosion Science | Year: 2012

The evolution of atmospheric corrosion of MnCuP weathering steel in a simulated coastal-industrial atmosphere was investigated by weight gain, SEM, XRD, and electrochemical measurements. The results indicate that the corrosion kinetics divides into two stages with a higher corrosion rate in the first stage and a lower rate in the second stage. The increased amount of α-FeOOH indicates an improved resistance of the rust. The rust enhances initially and then stabilizes the cathodic process, but the anodic process tends to be inhibited. The EIS results indicate that the protective ability of the rust layer can be evaluated by the charge transfer resistance. © 2012.

An acceleration algorithm for the kinetic Monte Carlo simulation of breakage process during grinding is introduced. We show that a feedback approach can be used to accelerate simulation as much as possible while control the simulation accuracy under a threshold. This is implemented by introducing a quantitative measurement of simulation accuracy and an estimation method during simulation run-time. The analysis is supported by numerical results showing significant acceleration and accuracy being well controlled below the given threshold. © 2016 Elsevier B.V.

Zhang F.,University of Chinese Academy of Sciences | Liu G.,Ryerson University | Fang L.,Northeastern University China | Wang H.,CAS Shenyang Institute of Automation
IEEE Transactions on Industrial Electronics | Year: 2012

Battery state-of-charge (SOC) estimation is essential for a mobile robot, such as inspection of power transmission lines. It is often estimated using a Kalman filter (KF) under the assumption that the statistical properties of the system and measurement errors are known. Otherwise, the SOC estimation error may be large or even divergent. In this paper, without the requirement of the known statistical properties, a SOC estimation method is proposed using an H ∞ observer, which can still guarantee the SOC estimation accuracy in the worst statistical error case. Under the conditions of different currents and temperatures, the effectiveness of the proposed method is verified in the laboratory and field environments. With the comparison of the proposed method and the KF-based one, the experimental results show that the proposed method can still provide accurate SOC estimation when there exist inexact or unknown statistical properties of the errors. The proposed method has been applied successfully to the robot for inspecting the running 500-kV extra high voltage power transmission lines. © 2011 IEEE.

Liu T.,Australian National University | Hill D.J.,University of Sydney | Zhao J.,Northeastern University China
IEEE Transactions on Automatic Control | Year: 2012

In this note, we study locally controlled synchronization of a dynamical network by introducing a distributed controller which has a different network structure from the original network. We refer to this configuration as a feedback network. To reflect practical reality, a cost function is considered to constrain the controller, and then the constrained controller design problem is transformed into a mixed-integer nonlinear optimization problem. In addition, when a single controller cannot be found under the constraint, a switching controller is designed by a Lyapunov function method. The convex combination technique is used to design the synchronizing switching signal between the candidate controllers, and its coefficients are given by the solution of a convex optimization problem. We also provide a feasible way to construct the candidate controllers, and give a numerical example which demonstrates the effectiveness of the proposed results. © 2011 IEEE.

Che W.-W.,Shenyang University | Yang G.-H.,Northeastern University China
International Journal of Systems Science | Year: 2013

This article studies the quantised H∞ filtering problem for continuous-time systems with a type of dynamic quantisers, which are conjuncted with static quantisers via dynamic scalings. The static quantiser ranges are fully considered here for practical transmission channels requirements. A quantised H∞ filter design strategy is proposed, where a convex optimisation method is developed to minimise static quantiser ranges. The resulting design guarantees that the quantised augmented system is asymptotically stable and with a prescribed H∞ performance bound. The effectiveness of the proposed filter design method is demonstrated by a numerical example. © 2013 Copyright Taylor and Francis Group, LLC.

Wang J.,Northeastern University China
Safety Science | Year: 2013

Considering the role of the neighboring nodes of an overload node, we articulate a local protection strategy to address the problem of the optimal defense in the cascading propagation. From two aspects of the global robustness and the different attacks, we numerically demonstrate the effectiveness of this strategy on Barabási-Albert (BA) scale-free networks and the power grid, and show that the robustness of diverse networks against cascading failures can be improved dramatically. And we numerically find the optimal value of the parameter, at which two types of networks can reach the strongest robust level against cascading failures. Next, in BA networks we verify this finding by theoretical analysis. Our results may be very useful for constructing the optimal protection strategy in realistic networks and for leading to insights into the mitigation of cascading failures. © 2012 Elsevier Ltd.

Wen Y.,University of Queensland | Wang B.,University of Queensland | Huang C.,University of Queensland | Huang C.,Northeastern University China | And 2 more authors.
Chemistry - A European Journal | Year: 2015

Phosphorus-doped (P-doped) graphene with the P doping level of 1.30 at% was synthesized by annealing the mixture of graphene and phosphoric acid. The presence of P was confirmed by elemental mapping and X-ray photoelectron spectroscopy, while the morphology of P-doped graphene was revealed by using scanning electron microscopy and transmission electron microscopy. To investigate the effect of P doping, the electrochemical properties of P-doped graphene were tested as a supercapacitor electrode in an aqueous electrolyte of 1m H2SO4. The results showed that doping of P in graphene exhibited significant improvement in terms of specific capacitance and cycling stability, compared with undoped graphene electrode. More interestingly, the P-doped graphene electrode can survive at a wide voltage window of 1.7 V with only 3 % performance degradation after 5000 cycles at a current density of 5 Ag-1, providing a high energy density of 11.64 Whkg-1 and a high power density of 831 Wkg-1. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hao L.,CAS Shenyang Institute of Metal Research | Zhang S.,Northeastern University China | Zhang S.,Laiwu Steel Group | Dong J.,CAS Shenyang Institute of Metal Research | Ke W.,CAS Shenyang Institute of Metal Research
Corrosion Science | Year: 2012

The corrosion evolution of a Mo-Cu-bearing fire-resistant steel in a simulated industrial atmosphere was investigated by corrosion weight gain, XRD, EPMA, XPS, and polarization curves. The results indicate that the corrosion kinetics is closely related to the rust composition and electrochemical properties. As the corrosion proceeds, the relative content of γ-FeOOH and Fe3O4 decreases and α-FeOOH increases, and the rust layer becomes compact and adherent to steel substrate. Molybdenum and copper enrich in the inner rust layer, especially at the bottom of the corrosion nest, forming non-soluble molybdate and Cu(I)-bearing compounds responsible for enhanced corrosion resistance of the rust layer. © 2011.

Liu J.,Harbin Institute of Technology | Zhang X.X.,Northeastern University China
Knowledge-Based Systems | Year: 2016

Nowadays several labeling schemes are proposed to facilitate XML query processing, in which structural relationships among nodes could be quickly determined without accessing original XML documents. However, previous node indexing often encounters some troublesome problems when updates take place, such as a large amount of labels requiring re-labeling, huge space requirements for the updated labels, and inefficient determination of structural relationships. In this paper, we propose a novel labeling scheme that not only completely avoids re-labeling but also improves the performance of determining the structural relationships when XML documents are frequently updated at arbitrary positions. The fundamental difference between our scheme and previous ones is that, the gain in update performance of our labeling scheme does not come at the expense of the label size and the query performance. In particular, instead of completely assigning new labels for inserted nodes, the deleted labels are reused in our labeling scheme for encoding newly inserted nodes, which could effectively lower the label size. Moreover, we formally analyze the effectiveness of our proposed labeling scheme. Finally, we complement our analysis with experimental results on a range of real XML data.

Pan Q.-K.,Northeastern University China | Pan Q.-K.,Liaocheng University | Ruiz R.,Polytechnic University of Valencia
Computers and Operations Research | Year: 2013

In recent years, a large number of heuristics have been proposed for the minimization of the total or mean flowtime/completion time of the well-known permutation flowshop scheduling problem. Although some literature reviews and comparisons have been made, they do not include the latest available heuristics and results are hard to compare as no common benchmarks and computing platforms have been employed. Furthermore, existing partial comparisons lack the application of powerful statistical tools. The result is that it is not clear which heuristics, especially among the recent ones, are the best. This paper presents a comprehensive review and computational evaluation as well as a statistical assessment of 22 existing heuristics. From the knowledge obtained after such a detailed comparison, five new heuristics are presented. Careful designs of experiments and analyses of variance (ANOVA) techniques are applied to guarantee sound conclusions. The comparison results identify the best existing methods and show that the five newly presented heuristics are competitive or better than the best performing ones in the literature for the permutation flowshop problem with the total completion time criterion. © 2012 Elsevier Ltd. All rights reserved.

Qin H.-L.,Northeastern University China
Procedia Engineering | Year: 2011

According to the character of the high-rise buildings fire risk, this paper establishes the index system of fire risk on high-rise building, calculates the weight of every index by AHP, applies fuzzy pattern recognition model with the least summation of weighted generalized distance in fuzzy comprehensive assessment, sets up the fire risk assessment model of high-rise buildings based on the fuzzy pattern recognition and brings in fuzzy characteristic quantity of safety grade to deal with the assessment result of fire risk on high-rise building. At last, this method stated above is applied to some hotel in Xi'an which can provide available gist for performance-based fire protection design and safety management. © 2011 Published by Elsevier Ltd.

Li H.,Northeastern University China | Xie S.,Institute for Infocomm Research
IET Communications | Year: 2011

This study addresses the joint robust linear transceiver design problems for a downlink multi-user multiple-input multiple-output (MIMO) antenna system in the presence of imperfect channel state information (CSI). The uncertainty in the channel is characteried by a norm-bounded region, and two robust optimal design problems are considered. One is aimed at minimising the total transmitter power subject to users' mean square error (MSE) constraints in the presence of channel uncertainty, the other is to minimise the worst-case sum-mean square error (sum-MSE) under power constraints for all admissible uncertainties. For these two problems, the authors propose two iterative algorithms based on second-order cone programming (SOCP) formulations, which can be efficiently solved and have less computational complexity than their semi-definite programming (SDP) counterparts. Simulation results also illustrate that the proposed robust design approaches can significantly reduce the computational complexity while achieving almost the same performance as the robust SDP methods. © 2011 The Institution of Engineering and Technology.

Conventional hot compression deformation and water quenching experiments were applied to investigate the evolution of austenite grain structures before the initiation of dynamic recrystallization. The experimental results reveal an interesting phenomenon that dynamic strain - induced boundary migration can lower dislocation density and coarsen austenite grains. The results show that dynamic recovery is not the only way to decrease dislocation density, the mechanism of which for dynamic recovery is related to dislocations climb and annihilation, resulting in the formation of sub-grains and regular sub-boundaries. However, the mechanism of decreasing dislocation density for dynamic strain - induced boundary migration is different from dynamic recovery. Therefore, dynamic strain - induced boundary migration should be another softening mechanism before the initiation of dynamic recrystallization. © (2014) Trans Tech Publications, Switzerland.

Wang L.,Northeastern University China | Yung N.H.C.,University of Hong Kong
IEEE Transactions on Intelligent Transportation Systems | Year: 2012

In this paper, the problem of human detection in crowded scenes is formulated as a maximum a posteriori problem, in which, given a set of candidates, predefined 3-D human shape models are matched with image evidence, provided by foreground extraction and probability of boundary, to estimate the human configuration. The optimal solution is obtained by decomposing the mutually related candidates into unoccluded and occluded ones in each iteration according to a graph description of the candidate relations and then only matching models for the unoccluded candidates. A candidate validation and rejection process based on minimum description length and local occlusion reasoning is carried out after each iteration of model matching. The advantage of the proposed optimization procedure is that its computational cost is much smaller than that of global optimization methods, while its performance is comparable to them. The proposed method achieves a detection rate of about 2% higher on a subset of images of the Caviar data set than the best result reported by previous works. We also demonstrate the performance of the proposed method using another challenging data set. © 2011 IEEE.

Chai T.,Northeastern University China | Jin Y.,University of Surrey | Sendhoff B.,Honda Research Institute Europe
IEEE Computational Intelligence Magazine | Year: 2013

The papers in this special section focus on the challenges and future direction of evolutionary complex engineering. © 2005-2012 IEEE.

Zhang C.,Northeastern University China | Ouyang D.,Key Laboratory of Symbol Computation and Knowledge Engineering | Ning J.,Northeast Normal University
Expert Systems with Applications | Year: 2010

Clustering is a popular data analysis and data mining technique. In this paper, an artificial bee colony clustering algorithm is presented to optimally partition N objects into K clusters. The Deb's rules are used to direct the search direction of each candidate. This algorithm has been tested on several well-known real datasets and compared with other popular heuristics algorithm in clustering, such as GA, SA, TS, ACO and the recently proposed K-NM-PSO algorithm. The computational simulations reveal very encouraging results in terms of the quality of solution and the processing time required. © 2009 Elsevier Ltd. All rights reserved.

Song R.,University of Science and Technology Beijing | Wei Q.,CAS Institute of Automation | Sun Q.,Northeastern University China
Neurocomputing | Year: 2015

In this paper, a novel adaptive dynamic programming (ADP) algorithm is developed to solve the nearly optimal finite-horizon control problem for a class of deterministic nonaffine nonlinear time-delay systems. The idea is to use ADP technique to obtain the nearly optimal control which makes the optimal performance index function close to the greatest lower bound of all performance index functions within finite time. The proposed algorithm contains two cases with respective different initial iterations. In the first case, there exists control policy which makes arbitrary state of the system reach to zero in one time step. In the second case, there exists a control sequence which makes the system reach to zero in multiple time steps. The state updating is used to determine the optimal state. Convergence analysis of the performance index function is given. Furthermore, the relationship between the iteration steps and the length of the control sequence is presented. Two neural networks are used to approximate the performance index function and compute the optimal control policy for facilitating the implementation of ADP iteration algorithm. At last, two examples are used to demonstrate the effectiveness of the proposed ADP iteration algorithm. © 2014 Elsevier B.V.

This paper presents a framework for modeling and optimizing the glutamic acid fermentation process using computational intelligence techniques. Considering the special characteristics of such an industrial process, we propose a two-phase optimization strategy to maximize the conversion rate and product concentration of the glutamic acid. Neural network ensembles and an improved Differential Evolutionary Algorithm (DEA) with a non-inferior sorting scheme and niche technology are employed for problem solving. This work provides an approach for design of a model-free optimal control system for the fed-batch fermentation process. Experimental results are promising and demonstrate the applicability of the proposed modeling and optimization techniques for real world applications. © 2015 Elsevier B.V.

Song R.,University of Science and Technology Beijing | Xiao W.,University of Science and Technology Beijing | Zhang H.,Northeastern University China
Neurocomputing | Year: 2013

In this paper, an optimal control method for a class of unknown discrete-time nonlinear systems with general multi-objective performance indices is proposed. In the design of the optimal controller, only available input-output data are required instead of known system dynamics, and the data-based identifier is established with stability proof. By the weighted sum technology, the multi-objective optimal control problem is transformed into the single objective optimization. To obtain the solution of the HJB equation, the novel finite-approximation-error adaptive dynamic programming (ADP) algorithm is presented with convergence proof. The detailed theoretic analyses for the relationship of the approximation accuracy and the algorithm convergence are given. It is shown that, as convergence conditions are satisfied, the iterative performance index functions can converge to a finite neighborhood of the greatest lower bound of all performance index functions. Neural networks are used to approximate the performance index function and compute the optimal control policy, respectively, for facilitating the implementation of the iterative ADP algorithm. Finally, two simulation examples are given to illustrate the performance of the proposed method. © 2013 Elsevier B.V.

Song Z.,Northeastern University China
Applied Thermal Engineering | Year: 2016

The purpose of this research was to identify the extent to which fan-assisted perforations represent an effective cooling system in a contained, raised-floor data center that has some degree of leakage. Numerical construction and thermal analyses were employed using a Computational Fluid Dynamics (CFD) technique. The flow-straightening effect was tested in terms of two distinct aspects of a data center configuration that incorporate a fan-assisted perforation system, namely the fan-assisted tile and the fan-to-tile distance. The ways in which these two parameters impacted the field cooling function was assessed and compared. The research evaluates a full factorial design as a means of ascertaining both the qualitative and quantitative effect of a given set of design variations. The outputs of the study indicate that, providing they are accurately and efficiently constructed, fan-assisted perforations represent a viable method by which energy contained aisle data centers can be efficiently managed. © 2016 Elsevier Ltd. All rights reserved.

Chu M.,Northeastern University China | Yagi J.-I.,Tohoku University
Steel Research International | Year: 2010

The new process of top gas recycling by hot reducing gas (HRG) injection has been developed in this study in order to overcome the disadvantageous problems under the lower temperature operation, to enhance the utilization of top gas carbon and to reduce carbon dioxide emission of blast furnaces. Numerical evaluation of blast furnace top gas recirculation together with lower-temperature operation was performed by means of a multi-fluid blast furnace model. The simulation results show that, (1) under the lower temperature operation, the shaft injection, or simultaneous shaft and tuyere injection of hot reducing gas is effective to increase the heat supply and to enrich the reduction atmosphere in the shaft zone, to improve the reduction of iron burdens, and enhance the efficiency of the shaft zone. (2) If top gas is recirculated by HRG on the basis of lower temperature operation, a highly efficient low-carbon blast furnace is obtained. The productivity of the furnace shows a remarkable increase and the total reducing agent rate shows a considerable decrease. Furthermore, the top gas carbon utilization is enhanced and the carbon dioxide emission rate is lowered. (3) Generally, shaft efficiency, carbon emission and heat efficiency under simultaneous tuyere and shaft injection are comparatively better than in the other two methods of single injection. Copyright © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Jia P.,Northeastern University China | Liu J.-M.,CAS Shenyang Institute of Metal Research | Wang E.-G.,CAS Shenyang Institute of Metal Research | Han K.,Florida State University
Journal of Alloys and Compounds | Year: 2013

We report that the high magnetic field (HMF) retards crystallization, i.e. helps to keep a fully amorphous state of bulk metallic glass (BMG) upon isothermal annealing in the supercooled liquid region. Particularly, the application of HMF during an annealing process can effectively suppress the crystallization of boride (e.g. Fe23B6-type phase, or even a hard magnetic Fe2B phase) from the amorphous matrix of Fe 71(Nb0.8Zr0.2)6B23 BMG. Thus by delaying crystallization, HMF can enhance the soft magnetic properties of high B content Fe-based bulk amorphous and nanocrystalline materials. © 2013 Elsevier B.V. All rights reserved.

Liu H.S.,CAS Shenyang Institute of Metal Research | Zhang B.,Northeastern University China | Zhang G.P.,CAS Shenyang Institute of Metal Research
Scripta Materialia | Year: 2011

Here we reveal that a Cu/Cu laminated composite with an appropriate mechanical contrast between constituent layers can effectively improve the toughness and fatigue strength of cold rolled Cu. The local interface delamination-induced retardation of cracking and the secondary initiation of fatigue cracks at inner layer surfaces are the main mechanisms. Such the single material laminated with mechanical contrast provides a potential way to improve fatigue strength. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Liu H.S.,CAS Shenyang Institute of Metal Research | Zhang B.,Northeastern University China | Zhang G.P.,CAS Shenyang Institute of Metal Research
Scripta Materialia | Year: 2011

A cold-rolled metal sheet is usually of high strength but low plasticity due to the onset of premature local necking. Here, we reveal that the tensile plasticity of cold-rolled Cu can be effectively enhanced by a layered structure stacked alternately by thicker Cu and thinner Al layers. The layer interface in the composite strongly constrains and delays the development of premature local necking of the cold-rolled Cu layer. A potential way to improve plasticity without losing strength is suggested. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Song H.,State University of New York at Buffalo | Guo L.,Fudan University | Liu Z.,Fudan University | Liu K.,State University of New York at Buffalo | And 6 more authors.
Advanced Materials | Year: 2014

A fundamental strategy is developed to enhance the light-matter interaction of ultra-thin films based on a strong interference effect in planar nanocavities, and overcome the limitation between the optical absorption and film thickness of energy harvesting/conversion materials. This principle is quite general and is applied to explore the spectrally tunable absorption enhancement of various ultra-thin absorptive materials including 2D atomic monolayers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhao C.,Hong Kong University of Science and Technology | Yao Y.,Hong Kong University of Science and Technology | Gao F.,Hong Kong University of Science and Technology | Wang F.,Northeastern University China
Chemical Engineering Science | Year: 2010

In the present work, an improved statistical analysis, modeling and monitoring strategy is proposed for multimode processes with between-mode transitions. The subject of analysis is multi-source measurement data, with each source of data corresponding to one operation mode. The basic assumption is that the underlying correlations among the different modes are similar to a certain extent and a multimode common community can thus be enclosed by some common bases immune to the mode changes. By making an adequate projection of measurement space, the mode-common subspace is separated and can be represented by a robust statistical model. The remaining mode-specific subspace would be more specific to different operation modes. Moreover, a between-mode transition identification algorithm is designed, which can distinguish the normal transition behaviors from those abnormal disturbances. The proposed method provides a detailed insight into the inherent nature of multimode processes from both inter-mode and inner-mode viewpoints. More process information is captured which enhances one's understanding of the multimode problem. Its feasibility and performance are illustrated with a practical case. © 2010 Elsevier Ltd.

Guo D.,National University of Defense Technology | Wu J.,Temple University | Chen H.,National University of Defense Technology | Yuan Y.,Northeastern University China | Luo X.,National University of Defense Technology
IEEE Transactions on Knowledge and Data Engineering | Year: 2010

A Bloom filter is an effective, space-efficient data structure for concisely representing a set, and supporting approximate membership queries. Traditionally, the Bloom filter and its variants just focus on how to represent a static set and decrease the false positive probability to a sufficiently low level. By investigating mainstream applications based on the Bloom filter, we reveal that dynamic data sets are more common and important than static sets. However, existing variants of the Bloom filter cannot support dynamic data sets well. To address this issue, we propose dynamic Bloom filters to represent dynamic sets, as well as static sets and design necessary item insertion, membership query, item deletion, and filter union algorithms. The dynamic Bloom filter can control the false positive probability at a low level by expanding its capacity as the set cardinality increases. Through comprehensive mathematical analysis, we show that the dynamic Bloom filter uses less expected memory than the Bloom filter when representing dynamic sets with an upper bound on set cardinality, and also that the dynamic Bloom filter is more stable than the Bloom filter due to infrequent reconstruction when addressing dynamic sets without an upper bound on set cardinality. Moreover, the analysis results hold in stand-alone applications, as well as distributed applications. © 2006 IEEE.

Zhang Y.-B.,Hebei Polytechnic University | Liu S.-J.,Northeastern University China
Yantu Lixue/Rock and Soil Mechanics | Year: 2011

The hole rock is selected as a spesimen, and the thermal infrared radiation variation features of hole rock are experimentally studied in the process of loading by using uniaxial loading system and thermal imager, as well as combining the numerical simulation. It is revealed that the distribution of compression stress and tension stress on hole rock are symmetrical, which results in the symmetrical distribution of thermal image. The surface radiation temperature in tension stress area decreases and the radiation temperature in compression stress area increases. There is a fine corresponding relation between stress field and infrared radiation temperature field. In the later period of loading, rock appears fractures and the radiation temperature on shearing fracture is increasing; but the radiation temperature on the position of tension fracture is almost not changed. The fracturing type is closely related to the infrared radiation temperature variation. The rock fails finally along the shearing fracture; and the temperature-increase strip is the important infrared precursor of rock fracture and destabilization. The experimental results indicate again that the thermal imaging technology can detect the stress and catastrophe of rock.

Wang L.,Northeastern University China
IEEE Transactions on Electron Devices | Year: 2015

A property-induced differential structure, which includes negative temperature coefficient unit (NTCU) and positive temperature coefficient unit (PTCU), is designed to increase the sensitivity of temperature sensor based on conductive polymer composite. The composite with/without cellular structure is used as the sensitive material in NTCU/PTCU, which results in a decrease/an increase of the electrical resistance with the increase of the temperature. Through using NTCU and PTCU as the neighboring arms of an electrical bridge, the temperature is converted into a voltage. The results verify the feasibility of using the property-induced differential structure to improve the sensitivity. © 2015 IEEE.

Kobayashi S.,Ashikaga Institute of Technology | Kamata A.,Ashikaga Institute of Technology | Watanabe T.,Northeastern University China
Acta Materialia | Year: 2015

Quantitative investigation of the grain growth and resultant change in grain boundary microstructure during high-cycle fatigue was performed to understand intergranular fatigue fracture in electrodeposited nanocrystalline Ni - 2.0 mass% P alloys by using FE-SEM/EBSD technique. Pre-fatigued specimens had an average grain size of 45 nm, a sharp {0 0 1} texture and a high fraction of low-angle boundaries and of twin, or Σ3 coincidence site lattice (CSL) boundaries. The considerable grain growth occurred due to the migration of low-angle boundaries induced by shear stress during cyclic deformation. The misorientation angle of those low-angle boundaries increased covering the whole surface of fatigue-fractured specimen. A certain fraction of low-angle boundaries was transformed into high-angle random boundaries resultant from grain growth during high-cycle fatigue. Those random boundaries which surrounded the grown {0 0 1}-grains were aligned along shear bands at almost 45° to the stress axis, and formed the diamond-shaped grain configuration, as reported in the literature on high temperature fatigue. The reported increase of the fatigue limit by nanocrystallization is likely reduced due to the cyclic stress-induced grain growth associated with the migration of low-angle boundaries composing nanograin cluster. Moreover, the random boundaries transformed from low-angle boundaries can be preferential sites for crack nucleation and propagation at the positions of initially formed shear bands during fatigue. © 2015 Acta Materialia Inc.

Zhang H.,Northeastern University China | Wei Q.,CAS Institute of Automation | Liu D.,CAS Institute of Automation
Automatica | Year: 2011

In this paper, a new iterative adaptive dynamic programming (ADP) method is proposed to solve a class of continuous-time nonlinear two-person zero-sum differential games. The idea is to use the ADP technique to obtain the optimal control pair iteratively which makes the performance index function reach the saddle point of the zero-sum differential games. If the saddle point does not exist, the mixed optimal control pair is obtained to make the performance index function reach the mixed optimum. Stability analysis of the nonlinear systems is presented and the convergence property of the performance index function is also proved. Two simulation examples are given to illustrate the performance of the proposed method. © 2010 Elsevier Ltd. All rights reserved.

Song C.,Northeastern University China
Mathematical Problems in Engineering | Year: 2015

The sliding mode control and the model predictive control are connected by the value function of the optimal control problem for constrained fuzzy system. New conditions for the existence and stability of a sliding mode are proposed. Those conditions are more general conditions for the existence and stability of a sliding mode. When it is applied to the controller design, the design procedures are different from other sliding mode control (SMC) methods in that only the decay rate of the sliding mode motion is specified. The obtained controllers are state-feedback model predictive control (MPC) and also SMC. From the viewpoint of SMC, sliding mode surface does not need to be specified previously and the sliding mode reaching conditions are not necessary in the controller design. From the viewpoint of MPC, the finite time horizon is extended to the infinite time horizon. The difference with other MPC schemes is that the dependence on the feasibility of the initial point is canceled and the control schemes can be implemented in real time. Pseudosliding mode model predictive controllers are also provided. Closed loop systems are proven to be asymptotically stable. Simulation examples are provided to demonstrate proposed methods. © 2015 Chonghui Song.

Sun M.,Northeastern University China | Jia Y.,Beihang University
IET Control Theory and Applications | Year: 2010

In this study, a delay-dependent H∞ performance criterion that possess decoupling structure is derived for a class of time-delay systems. It is then extended to H∞ state-feedback synthesis for time-delay systems with polytopic uncertainty and multichannel H ∞ dynamic output-feedback synthesis for time-delay systems. All the conditions are given in terms of the linear matrix inequalities. In some previous descriptor methods, the products of controller matrices and Lyapunov matrices are completely separated in performance analysis, whereas it is not the case in controller synthesis. However, with the method in the paper, the weakness is eliminated. Numerical examples illustrate the effectiveness of our solutions as compared to results obtained by other methods. © 2010 The Institution of Engineering and Technology.

Gao T.,Northeastern University China
Journal of Water Resources Planning and Management | Year: 2014

A valve-enclosed segment is the basic unit of water distribution networks (WDNs) in reliability analysis and optimal design. Based on the theory of the transitive closure of graphs, this paper presents a new method for identifying the whole segments in large WDNs in a single run. The method clones real valves as fictitious valves, uses valve pairs to simulate valve on-off status, and improves the Warshall algorithm to compute node transitive closure sets to identify all segments at a time. Additionally, redundant valves, endpoint valves, leaf segments, orphan segments, and regular segments are analyzed. One-way valves are considered in an unintended segment analysis. The method is described and discussed in detail by using a small sample network, then applied to a large real network containing 69,815 valves to prove its capability and efficiency. © 2014 American Society of Civil Engineers.

Wu L.-X.,Beijing Normal University | Wu L.-X.,China University of Mining and Technology | Qin K.,China University of Mining and Technology | Liu S.-J.,Northeastern University China
Proceedings of the IEEE | Year: 2012

Although earthquakes are difficult to be predicted because of the complexity of the Earth system and the uncertainty of seismogenic processes, GEOSS provides multiple sources of observation data and brings a possibility to extract a thermal anomaly that would have a significant effect on earthquake prediction. Referring to the analysis on the lithosphere-coversphere-atmosphere (LCA) coupling due to stress enhancement in seismogenic zone, six thermal parameters, including surface latent heat flux (SLHF), thermal infrared radiation (TIR), outgoing longwave radiation (OLR), diurnal temperature range (DTR), atmospheric temperature, and skin temperature, are selected for GEOSS-based earthquake anomaly recognition (EAR). The inherent relations between the six thermal parameters are preliminarily introduced in consideration of possible LCA coupling. With overquantity, quasi-synchronism, and geo-consistency being defined as three rules for data mining, a deviation-time-space-thermal (DTS-T) EAR method as well as its procedures are developed in this paper. With 2008 M7.3 Yutian earthquake, China, 2008 M8.0 Wenchuan earthquake, China, and 2010 M7.1 Christchurch earthquake, New Zealand, being examples of tectonic earthquakes, the technical procedures of DTS-T method are demonstrated, which show that the obtained compositive thermal anomaly has a significant effect on earthquake prediction. © 2012 IEEE.

Li W.,Ludong University | Liu X.,Ludong University | Zhang S.,Northeastern University China
Automatica | Year: 2012

This paper aims to relax the results in Xie and Tian (2009) from the following two aspects: completely removing the power order restriction and largely relaxing the growth conditions of nonlinear functions. By using the backstepping design method and homogeneous domination technique, this paper investigates the problem of adaptive state-feedback stabilization for a class of stochastic high-order nonlinear systems with nonlinear parameterization. The closed-loop system can be proved to be globally stable in probability and the states can be regulated to the origin almost surely. The efficiency of the adaptive state-feedback controller is demonstrated by a simulation example. © 2012 Elsevier Ltd. All rights reserved.

Han Q.,Northeastern University China
International Journal of Structural Stability and Dynamics | Year: 2011

This paper proposes two control strategies for the motion synchronization of the masterslave manipulators based on their ender trajectories. First, the basic equations used by the two control methods for motion synchronization are presented. Such procedures are proved to be stable for negative definite gain matrices, according to the Lyapunov theory. Then, the controlled items of the slave manipulator are determined for the ender trajectory synchronization by the coordinate transformations between the joint variables and the ender trajectory in the form of pseudo-Jacobian matrix. Finally, the two control methods for synchronization are validated by the numerical simulation for a masterslave system consisting of two planar three-degree-of-freedom (3-DOF) manipulators. © 2011 World Scientific Publishing Company.

Zhang Y.,Northeastern University China
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2013

Along with the development of industry and modern science, the performance of the mechanical product increases continuously and the mechanical system and work environment become more complex. The problems for the performance and reliability of the product become more and more prominent. It is very important and urgent to research the area of reliability of the mechanical product. Based on the research of mathematics, mechanics, material science and mechanical engineering, the basic task of mechanical reliability design is to propose mathematical-mechanical models and methods for engineering practice in mechanical product design by integrating the reliability experiment and statistical analysis of the failure data. Dynamic and gradual changing over time are universal characteristics of mechanical systems during service lifetime. Structural dynamic and time-dependent reliability analyses needs theories and methodologies in terms of mechanical dynamics, strength deterioration mechanism, random processes, probability theory, reliability analysis and design, etc. With the developments during past decades, methods on dynamic and gradual reliability analysis of system are reviewed. © 2013 Journal of Mechanical Engineering.

Wang L.,Northeastern University China
IEEE Transactions on Instrumentation and Measurement | Year: 2015

To realize the compressive pressure measurement and the noncontact gap measurement in the small interlayer structure of industrial equipment, a compressive pressure and noncontact gap sensing element based on eddy-current effect is designed and fabricated by covering a polydimethylsiloxane film on the 2-D coil. The impedance of the 2-D coil in the sensing element is used to reflect the compressive pressure and the noncontact gap. There exists a critical impedance, which can be used to judge whether the sensing element contacts the metal object or not. At the noncontact stage, the impedance amplitude and the impedance angle of the 2-D coil increase with the increase of the gap between the sensing element and the object made of aluminum. At the contact stage, the impedance amplitude and impedance angle decrease with the increase of the compressive pressure. The experimental results verify the feasibility of using the 2-D coil covered with polydimethylsiloxane film to measure the compressive pressure and the noncontact gap. © 1963-2012 IEEE.

Zhang X.,Northeastern University China
Proceedings of the World Congress on Intelligent Control and Automation (WCICA) | Year: 2012

This paper discusses strict linear matrix inequalities(LMIs) sufficient condition which can be removed of the equality constraint for linear continuous singular systems. The criteria of stability and stabilization of continuous singular system are presented. The conditions are expressed in terms of strict positive definite LMIs which can reduce the equality constraint and semi-positive definite LMIs and are much more tractable and reliable in numerical computation than existing conditions. The conditions make use of only the system parameter matrices (E,A,B) directly by a restricted equivalent transform without introducing other adjective parameters. A counterexample is given to illustrate the criteria are only a sufficient condition but not are a necessary condition. The idea presented can help to find necessary and sufficient strict LMI criteria without equality constraint conditions of stability and stabilization of continuous singular system. © 2012 IEEE.

Liu X.-H.,Northeastern University China
Journal of Iron and Steel Research International | Year: 2011

Variable gauge rolling (VGR) is a new technology to produce flat products with different thicknesses (FDT), which could be used to replace conventional flat products in order to save metals and reduce structure mass. The method of VGR was introduced for investigating new problems in rolling theory of VGR, and the new formulas for calculating parameters of VGR were proposed. Besides, some results of numerical simulation by finite element method were described. As an example, the products applications of FDT in bridge construction, ship building and auto manufacturing were presented. Finally, the prospects for VGR and FDT were discussed. © 2011 Central Iron and Steel Research Institute.

Wang Y.S.,Northeastern University China
International Journal of Online Engineering | Year: 2015

With the development of enterprise information, data resources have become one of the most important assets of enterprises. This paper summarizes the current problems of data resource management for the Jinshandian Iron Mine and then analyzes the areas of standards, organizations, systems, processes and management tools. It provides an implementation guide and presents the problems that were faced in practice with the recommended solutions. The results of a practical application show that it has significance for implementing a data resource management system of mine enterprises.

He J.-C.,Northeastern University China
ISIJ International | Year: 2011

This article reviews the sustained and fast development of China's iron & steel industry since the reform and opening-up, the serious impact of the global financial crisis in 2008 on China's iron & steel industry and the domestic and foreign market backgrounds which rapidly brought China's iron & steel industry into downturn. It introduces the important measures the Chinese government has taken to expand domestic demand and restrain economic decline. It analyses the profound problems accumulated during the longterm rapid development of China's iron & steel industry and the challenges it faces. It raises important issues which need attention and main measures which should be adopted for China's iron & steel industry to react to the crisis and realize long-term and stable development. © 2011 ISIJ.

Zhao C.,Hong Kong University of Science and Technology | Gao F.,Hong Kong University of Science and Technology | Wang F.,Northeastern University China
AIChE Journal | Year: 2010

An improved independent component regression (M-ICR) algorithm is proposed by constructing joint latent variable (LV) based regressors, and a quantitative statistical analysis procedure is designed using a bootstrap technique for model validation and performance evaluation. First, the drawbacks of the conventional regression modeling algorithms are analyzed. Then the proposed M-ICR algorithm is formulated for regressor design. It constructs a dual-objective optimization criterion function, simultaneously incorporating quality-relevance and independence into the feature extraction procedure. This ties together the ideas of partial-least squares (PLS), and independent component regression (ICR) under the same mathematical umbrella. By adjusting the controllable suboptimization objective weights, it adds insight into the different roles of quality-relevant and independent characteristics in calibration modeling, and, thus, provides possibilities to combine the advantages of PLS and ICR. Furthermore, a quantitative statistical analysis procedure based on a bootstrapping technique is designed to identify the effects of LVs, determine a better model rank and overcome ill-conditioning caused by model over-parameterization. A confidence interval on quality prediction is also approximated. The performance of the proposed method is demonstrated using both numerical and real world data. © 2009 American Institute of Chemical Engineers.

Liu G.-Y.,Jilin University | Wang H.-Y.,Jilin University | Liu G.-Q.,Northeastern University China | Yang Z.-Z.,Jilin University | And 2 more authors.
Electrochimica Acta | Year: 2013

Dual-phase Li4Ti5O12-TiO2 nanocrystallines are prepared by a hydrothermal process and subsequent heat treatment. The as-prepared Li4Ti5O12-TiO 2 nanocrystallines measure around 15-25 nm in size and have abundant phase interfaces. Electrochemical measurements demonstrate that dual-phase Li4Ti5O12-TiO2 exhibit good electrochemical performance over individual single-phase Li4Ti 5O12, especially at high current rates. Initial discharge capacities of dual-phase Li4Ti5O12-TiO 2 nanocrystallines are 241 and 202 mAh g-1 at discharge rates of 0.2 and 5 C, respectively. Even after 50 cycles at 20 C, the capacity still remains 140 mAh g-1, which is four times greater than that of single-phase Li4Ti5O12 (29 mAh g-1). The high electrochemical performance indicates that dual-phase Li 4Ti5O12-TiO2 nanocrystallines are highly promising anode materials for lithium ion battery applications. © 2012 Elsevier Ltd.

Zhang Y.,Northeastern University China
International Journal of Project Management | Year: 2016

In risk response analysis, risks are often assumed independently. In fact, however, risks in a project mutually affect and the independent risk seldom exists in reality. This paper provides an approach to quantitatively measure the risk interdependence. Based on the analysis of the risk interdependence, we construct an optimization model for selecting risk response strategies considering the expected risk loss, risk interdependence and its two directions. Further, the effects of the risk interdependence on risk response can be investigated. There are two major findings by the analysis of the case project. First, the expected utility would be more sensitive to the risk interdependence itself than to the directions of it. Second, the insufficient attention paid to or neglect of the risk interdependence would lower the expected utility and increase the implementation cost. © 2016 Elsevier Ltd and Association for Project Management and the International Project Management Association.

Ren F.,Northeastern University China
Journal of Information Science | Year: 2014

The large amount of scientific papers provides a convenient way for users to know the latest research progress of a specific research topic. However, the large volume and the diverse research themes hiding among these papers usually hinder users from conveniently locating the specific papers that they are interested in. To tackle this problem, we propose a novel unsupervised cascade learning scheme that aims to extract a 'cluster-theme keywords' structure from the related papers of a research topic so as to help users locate their research interests quickly. Our approach first selects some representative papers for a research topic. It then clusters these selected papers into several small clusters with the help of a domain ontology. It finally extracts some theme keywords for each cluster. Our approach not only greatly reduces the time-consuming and labour-intensive paper-seeking process for users, but also comprehensively displays the diverse themes of a research topic. We conducted extensive experiments to evaluate our proposed approach. The experimental results demonstrate the effectiveness of this approach, which produces promising results. © The Author(s) 2013.

Wang J.,Northeastern University China
International Journal of Modern Physics C | Year: 2012

According to the dynamical characteristics of the local redistribution of the load on a removal node, by the reconnection of the neighboring edge of the most vulnerable node, we propose an effective method to improve the network robustness against cascading failures. Under two constraints, i.e. keeping the degree of each node unchanged and fixing the total protective cost of a network, we investigate the efficiency of the swap method on scale-free networks and analyze the correlation between the optimized network and the Pearson correlation coefficient. We numerically show that effective swapping of the small part of connections can dramatically improve the network robust level against cascading failures and find that the optimized networks obtained by the swap method exhibit an extremely disassortative degree-degree correlation, that is, the disassortativity decreases the robustness of the optimized network against cascading failures. While the extent of the disassortative mixing is decided by the parameters in the cascading model. In addition, we also compare the average path length and the diameter of the optimized and the original networks. © 2012 World Scientific Publishing Company.

Watanabe T.,Northeastern University China | Watanabe T.,Tohoku University
Journal of Materials Science | Year: 2011

A brief introduction of the historical background of grain boundary engineering for structural and functional polycrystalline materials is presented herewith. It has been emphasized that the accumulation of fundamental knowledge about the structure and properties of grain boundaries and interfaces has been extensively done by many researchers during the past one century. A new approach in terms of the concept of grain boundary and interface engineering is discussed for the design and development of high performance materials with desirable bulk properties. Recent advancements based on these concepts clearly demonstrate the high potential and general applicability of grain boundary engineering for various kinds of structural and functional materials. Future prospects of the grain boundary and interface engineering have been outlined, hoping that a new dimension will emerge pertaining to the discovery of new materials and the generation of a new property originating from the presence of grain boundaries and interfaces in advanced polycrystalline materials. © 2011 Springer Science+Business Media, LLC.

Zhang R.,Northeastern University China | Castel A.,CNRS Materials and Construction Durability Laboratory | Francois R.,CNRS Materials and Construction Durability Laboratory
Cement and Concrete Research | Year: 2010

This paper deals with the evolution of the corrosion pattern based on two beams corroded by 14 years (beam B1CL1) and 23 years (beam B2CL1) of conservation in a chloride environment. The experimental results indicate that, at the cracking initiation stage and the first stage of cracking propagation, localized corrosion due to chloride ingress is the predominant corrosion pattern and pitting corrosion is the main factor that influences the cracking process. As corrosion cracking increases, general corrosion develops rapidly and gradually becomes predominant in the second stage of cracking propagation. A comparison between existing models and experimental results illustrates that, although Vidal et al.'s model can better predict the reinforcement corrosion of beam B1CL1 under localized corrosion, it cannot predict the corrosion of beam B2CL1 under general corrosion. Also, Rodriguez's model, derived from the general corrosion due to electrically accelerated corrosion experiments, cannot match natural chloride corrosion irrespective of whether corrosion is localized or general. Thus, for natural general corrosion in the second stage of cracking propagation, a new model based on the parameter of average steel cross-section loss is put forward to predict steel corrosion from corrosion cracking. © 2009 Elsevier Ltd. All rights reserved.

Tian H.,Tianjin Polytechnic University | Wang A.,Northeastern University China
ISIJ International | Year: 2010

Fault diagnosis plays an important role during the process of blast furnace ironmaking for producing safety. In this paper the important parameters of puddling process are selected as judgments criterions of fault diagnosis by analyzing the changes of these parameters. Support vector machine (SVM) is used to establish the fault diagnosis model for its suitable characters for fault classification. But the stability and accuracy of model based on single SVM could not meet the needs of practical ironmaking. Therefore, a SVM ensemble based on bagging is presented to establish a novel fault diagnosis system. The real-time producing data are collected in 5# blast furnace of a steel enterprise for training and testing the fault diagnosis models with single SVM and SVM ensemble. The experiments about the comparison between single SVM and SVM ensemble and about the SVM ensembles with different number of individual SVM are made. The experimental results demonstrate that the performance of novel fault diagnosis system based on SVM ensemble is better than the one based on single SVM, and the best fault diagnosis system that can meet the practical needs of ironmaking is found. © 2010 ISIJ.

Zhao Y.,Northeastern University China | Zikanov O.,University of Michigan | Krasnov D.,TU Ilmenau
Physics of Fluids | Year: 2011

Instability of a flow of an electrically conducting fluid in an annular channel is analyzed. Strong constant magnetic field is imposed in the axial direction. Similarly to toroidal duct experiments, the flow is driven by the azimuthal Lorentz force resulting from the interaction between the magnetic field and the radial electric currents created by a difference of electric potential imposed between the cylinders. The instability of the base flow, while clearly of centrifugal nature, is significantly different from the Dean instability detected earlier in hydrodynamic systems and similar MHD systems at low and moderate magnetic fields. Growing perturbations are oscillating and axisymmetric and consist of counter-rotating toroidal vortices arranged side by side in the radial direction and having meridional cross-sections in the form of elongated ellipses oriented slightly obliquely to the axial direction. Simulations of the secondary flow show an interesting feature of periodic transitions between two symmetric solutions. © 2011 American Institute of Physics.

Xu Y.,New Mexico State University | Liu W.,New Mexico State University | Gong J.,Northeastern University China
IEEE Transactions on Power Systems | Year: 2011

If generation in a power system is insufficient to power all loads, efficient load shedding operations may need to be deployed to maintain the supply-demand balance. This paper proposes a distributed multi-agent-based load shedding algorithm, which can make efficient load shedding decision based on discovered global information. During the information discovery process, only communications between immediate neighboring agents are used. The information discovery algorithm is represented as a discrete time linear system and the stability of which is analyzed according to average-consensus theorem. According to rigorous stability analysis, convergence of the designed algorithm can be guaranteed. To improve the speed of the algorithm, particle swarm optimization (PSO) is used to optimize the coefficients for information exchange so that the second largest eigenvalue of the iteration matrix is minimized. According to the designed algorithm, total net active power and operating status of loads can be discovered accurately even with faults. Based on the discovered information, coordinated load shedding decision can be made. © 2006 IEEE.

Ma X.-L.,Northeastern University China
Guangzi Xuebao/Acta Photonica Sinica | Year: 2015

Based on the mathematical model of modulation transfer function in atmospheric turbulence, the combined effect of atmospheric coherence length and optical pupil diameter on integral resolution and spot radius were investigated. Approximate algebraic solutions of resolutions and spot radii are derived for long-term exposure and short-term exposure by use of interpolation method. The result shows that the resolution is mainly limited by the pupil diameter while the pupil diameter is smaller than atmospheric coherence length, and can be enhanced by increasing the value of the pupil diameter. However, the resolution will not be significantly improved with further increase of the pupil diameter, since the imaging performance is gradually limited by turbulence while the pupil diameter is larger than atmospheric coherence length. There are limiting values for the resolution and spot radius restricted by atmospheric coherence length while the ratio of the diameter to atmospheric coherence length tends to infinite. For short-term exposure, since the tilt effect due to large-scale eddies is eliminated, the integral resolution and the spot radius are better than that of long-term exposure. Especially, for the near field of short-term exposure, the maximum value of integral resolution is approximately increased by a factor of 3.5 and the minimum value of spot radius is approximately decreased by a factor of 1/2, as compared with the case of long-term exposure. ©, 2015, Chinese Optical Society. All right reserved.

Cui M.,Dalian University of Technology | Gao X.,Dalian University of Technology | Chen H.,Northeastern University China
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2011

Non-gray radiative properties of an absorbing, emitting, non-gray participating medium significantly increase the difficulty of solving the radiative transfer equation. This paper presents a new inverse approach for the equivalent gray radiative property of a non-gray medium. In this approach, the unknown equivalent gray radiative properties are treated as the optimization variables, and the errors to be minimized are the differences between the calculated temperatures and the measured ones. The measured data are simulated by solving the direct problem, in which a modified zonal method together with the Edwards exponential wide-band model is employed. In the inverse problem, the sensitivity coefficients are first calculated by the complex-variable-differentiation method, and then the least-square method and the Newton-Raphson iterative method are employed to minimize the target function. The effectiveness and efficiency of the inverse problem are demonstrated in an example, and another case is given to show the accuracy and potential of the proposed algorithm. The effects of the measurement error and the number of measurement points on the accuracy of the inverse analysis are also investigated in detail. © 2011 Elsevier Ltd.

Liu T.,Northeastern University China | Jiang Z.-P.,New York University
IEEE Transactions on Automatic Control | Year: 2015

This paper presents a new approach to event-triggered control for nonlinear uncertain systems by using the notion of input-to-state stability (ISS) and the nonlinear small-gain theorem. The contribution of this paper is threefold. First, it is proved that infinitely fast sampling can be avoided if the system is input-to-state stabilizable with the sampling error as the external input and the corresponding ISS gain is locally Lipschitz. No assumption on the existence of known ISS-Lyapunov functions is made in the discussions. Moreover, the forward completeness problem with event-triggered control is studied systematically by using ISS small-gain arguments. Second, the proposed approach gives rise to a new self-triggered sampling strategy for a class of nonlinear systems subject to external disturbances. If an upper bound of the external disturbance is known, then the closed-loop system can be designed to be robust to the external disturbance, and moreover, the system state globally asymptotically converges to the origin if the external disturbance decays to zero. Third, a new design method is developed for event-triggered control of nonlinear uncertain systems in the strict-feedback form. It is particularly shown that the ISS gain with the sampling error as the input can be designed to satisfy the proposed condition for event-triggered control and self-triggered control. © 2015 IEEE.

Wang X.,University of Hong Kong | Wang X.,Northeastern University China | Wong T.N.,University of Hong Kong | Wang G.,University of Hong Kong
Expert Systems with Applications | Year: 2012

A virtual enterprise (VE) is a dynamic alliance of companies collaborating for the accomplishment of a specific business goal. To establish a VE, it is very important for the VE initiator to select appropriate partners. General criteria such as price, lead time, quality, etc. are the major concerns for most VE initiators. However, in today's environmentally conscious society, environmental issues such as enterprise green image, product eco-design, etc. are increasingly receiving attention. Thus, it is worth to research on how to select the appropriate collaborative partners to establish an ecological VE. The objective of this paper is to establish a multi-agent system platform for individual companies to form an ecological VE based on ontology theory and intelligent agents. The ontological approaches include shared ontology construction, ontology matching, ontology integration, ontology storage and ontology reasoning. In the generalized case that the VE initiator is a manufacturer and the collaborating partner are suppliers, the multi-agent system comprises three types of intelligent agents, namely, knowledge manager agent (KMrA), manufacturer agent (MA) and supplier agent (SA). MA and SA represent the capabilities and interests of the VE initiator and the VE partners, respectively. KMrA is in charge of functioning sub-tasks of the ontological approach. To select partners for the ecological VE, the VE initiator will also consider the environmental criteria, in addition to the general supplier selection criteria such as price, quantity, quality and lead time. The environmental criteria may include factors such as environmental management, green image, green product and pollution control. The complete set of selection criteria, including the environmental criteria, are categorised into quantitative or qualitative criteria. The formation of ecological VE is then divided into two stages, that is, candidate supplier selection based on qualitative criteria, and ultimate supplier selection based on quantitative criteria. A simplified example is introduced to illustrate and justify the proposed ontological approaches and intelligent agent platform. © 2011 Elsevier Ltd. All rights reserved.

Wang L.,Northeastern University China
IEEE/ASME Transactions on Mechatronics | Year: 2015

An electrical bridge system based on differential structure is designed to improve the sensitivity of compressive pressure sensor based on the piezoresistivity of conductive polymer composite. As the sensor works in the condition where all of the subsensing elements have to bear the same pressure, the classical "excitation-induced differential structure" (i.e., the properties of the subsensing elements are the same, and they are arranged on the special positions to bear the reversed excitations) cannot be applied. To solve this problem, a "property-induced differential structure" (i.e., the subsensing elements are endowed with reversed properties by adjusting the mass ratio of conductive filler to polymer in the composite, and the responses of them are opposite when the pressure exerted on them are the same) is designed. If the mass ratio is lower/higher than the critical mass ratio, the destruction/ formation effect of the conductive network of the composite is dominant under compression, inducing that the changing tendency of the resistance of the element is consistent/opposite to that of the pressure. By using the subsensing elements with reversed properties as the arms of a bridge, the pressure is converted to output voltage. The experimental results verify the feasibility of using the bridge system based on the "property-induced differential structure" to improve the sensitivity. © 2015 IEEE.

Lian J.,Dalian University of Technology | Zhao J.,Northeastern University China
Circuits, Systems, and Signal Processing | Year: 2010

This paper investigates the robust H∞ control problem for a class of uncertain switched delay systems with parameter uncertainties, unknown nonlinear perturbations, and external disturbance. Based on the multiple Lyapunov functions method, a sufficient condition for the solvability of the robust H∞ control problem is derived by employing a hysteresis switching law and variable structure controllers.When the upper bounds of the nonlinear perturbations are unknown, an adaptive variable structure control strategy is developed. The use of the adaptive technique is to adapt the unknown upper bounds of the nonlinear disturbances so that the objective of asymptotic stabilization with an H∞-norm bound is achieved under the hysteresis switching law. A numerical example illustrates the effectiveness of the proposed design methods. © Springer Science+Business Media, LLC 2010.

Zhou J.,IRIS - International Research Institute of Stavanger | Wen C.,Nanyang Technological University | Yang G.,Northeastern University China
IEEE Transactions on Automatic Control | Year: 2014

In this paper, we study a general class of strict feedback nonlinear systems, where the input signal takes quantized values. We consider a stabilization problem for nonlinear uncertain systems via adaptive backstepping approach. The control design is achieved by introducing a hysteretic quantizer to avoid chattering and using backstepping technique. A guideline is derived to select the parameters of the quantizer. The designed controller together with the quantizer ensures the stability of the closed-loop system in the sense of signal boundedness. © 1963-2012 IEEE.

Yao S.,Shenyang University of Chemical Technology | Huang W.-Q.,Northeastern University China
International Journal of Intelligent Systems | Year: 2014

We are primarily concerned with the problem of aggregating multiple attributes with uncertainty to form an overall decision function. We introduce a new type of approach for aggregation called an induced ordered weighted evidential reasoning (IOWER) approach, which is inspired by an induced ordered weighted averaging operator and the evidential reasoning (ER) approach. In the IOWER approach, we use a belief decision matrix combined with an induced ordered weighting vector for problem modeling and the Dempster-Shafer theory of evidence for attribute aggregation. It is proved that the original ER algorithm is a special case of the IOWER algorithm. Then we examine the properties of the IOWER approach. One key point in the IOWER approach is to reorder the arguments in the form of distributed assessment structure. A kind "expected utility" order-inducing variable is proposed in the IOWER approach, which can make the alternative's advantages prominent. Finally, we present an illustrative example in which the result obtained with the new aggregation approach can be seen. © 2014 Wiley Periodicals, Inc.

Wang L.,Northeastern University China
IEEE/ASME Transactions on Mechatronics | Year: 2016

To develop a stretchable eddy current noncontact gap sensor, the metal coil is replaced by a spiral element based on conductive polymer composite (i.e., composite spiral element). The current in the composite spiral element forms a vortex flow. The eddy current effect occurs when a metal object approaches the composite spiral element carried with alternating current. The experimental data show that the impedance of the composite spiral element changes regularly with the gap between the composite spiral element and the metal object. The test results verify the feasibility of using a composite spiral element as a stretchable eddy current noncontact gap sensor. © 1996-2012 IEEE.

Xie Y.,Northeastern University China
Lecture Notes in Electrical Engineering | Year: 2016

To expand the using occasions, a kind of temperature and humidity measurement based on USB interface has been completed in which SHT10 is used as the temperature and humidity data collecting sensor, and the relative humidity is compensated by temperature at the same time. The USB interface chip CH340T is used to transfer the received data to PC for processing. In this paper, the system is described in detail from two aspects, hardware and software. Experiment shows the system has good measurement results. © Springer-Verlag Berlin Heidelberg 2016.

Wang S.,University of Oklahoma | Wang S.,Northeastern University China | Wang Y.,University of Oklahoma
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We explore the systematic uncertainties of using type Ia supernovae (SNe Ia) as cosmological probes, using the Supernova Legacy Survey Three Year data (SNLS3). We focus on studying the possible evolution of the stretch-luminosity parameter α and the color-luminosity parameter β, by allowing α and β to be function of redshift, z. We find no evidence for the redshift evolution of α. We find that without flux-averaging SNe, β is consistent with being a constant when only statistical uncertainties are included, but it increases significantly with z when systematic uncertainties are also included. The evolution of β becomes marginal when all the SNe are flux-averaged, and β is consistent with being a constant when only SNe at z≥0.04 are flux-averaged. Our results are insensitive to the light-curve fitter used to derive the SNLS3 sample, or the functional form of α(z) and β(z) assumed. It is likely that the apparent evolution of β with z for SNe without flux-averaging is a consequence of unknown systematic effects; flux-averaging reduces the impact of these effects by averaging them within each redshift bin. Assuming constant α and β, we find that the flux-averaging of SNe has a significant impact on the distance-redshift relation. © 2013 American Physical Society.

Tong S.,Liaoning University of Technology | He X.,Liaoning University of Technology | Li Y.,Liaoning University of Technology | Zhang H.,Northeastern University China
Fuzzy Sets and Systems | Year: 2010

This paper proposes an adaptive fuzzy robust control method for SISO nonlinear systems with nonlinear uncertainties, unmodeled dynamics and dynamic disturbances. Fuzzy logic systems are used to approximate the nonlinear uncertainties, with no prior knowledge of their bounds. Based on the modeled nonlinear uncertainties using fuzzy logic systems, a stable adaptive fuzzy backstepping robust controller is proposed by combining the backstepping technique with the small-gain approach. It is mathematically proven that the proposed adaptive fuzzy control approach can guarantee that the closed-loop system is uniformly bounded. The effectiveness of the proposed approach is illustrated via two examples. © 2009 Elsevier B.V. All rights reserved.

Dai S.-L.,Northeastern University China | Dai S.-L.,National University of Singapore | Lin H.,National University of Singapore | Ge S.S.,National University of Singapore
IEEE Transactions on Control Systems Technology | Year: 2010

This paper is concerned with the simultaneous stabilization of a collection of continuous-time linear time-invariant (LTI) plants whose feedback-control loops are closed via a shared digital communication network. Because of the limitation of communication capacity, only a limited number of controller-plant connections can be accommodated at any time instant. Therefore, it is necessary to carefully determine a scheduling policy so as to achieve a simultaneous stabilization for all these control loops. A sufficient condition on the existence of such a scheduling policy is presented for a collection of networked LTI systems with sampled- data controllers and uncertain network-induced delays. The proof for the schedulability condition is in a constructive way, which can also serve as a systematic method to design a scheduling policy. Finally, a scheduling-and-feedback-control codesign procedure is proposed for the simultaneous stabilization of the collection of networked LTI systems, and the effectiveness of the proposed codesign procedure is demonstrated with simulation results. © 2009 IEEE.

Guo W.,Georgia Institute of Technology | Guo W.,Xiamen University | Xue X.,Georgia Institute of Technology | Xue X.,Northeastern University China | And 4 more authors.
Nano Letters | Year: 2012

We present a new approach to fabricate an integrated power pack by hybridizing energy harvest and storage processes. This power pack incorporates a series-wound dye-sensitized solar cell (DSSC) and a lithium ion battery (LIB) on the same Ti foil that has double-sided TiO 2 nanotube (NTs) arrays. The solar cell part is made of two different cosensitized tandem solar cells based on TiO 2 nanorod arrays (NRs) and NTs, respectively, which provide an open-circuit voltage of 3.39 V and a short-circuit current density of 1.01 mA/cm 2. The power pack can be charged to about 3 V in about 8 min, and the discharge capacity is about 38.89 μAh under the discharge density of 100 μA. The total energy conversion and storage efficiency for this system is 0.82%. Such an integrated power pack could serve as a power source for mobile electronics. © 2012 American Chemical Society.

Chai T.,Northeastern University China
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2012

Process control should aim at not only ensuring that controlled variables to best follow their set points, but also requiring the optimal control for the operation of the whole plant to make the operational indices (e.g. quality, efficiency and consumptions during the production phase) into their targeted ranges. It also requires that operational indices for quality and efficiency should be enhanced as high as possible, whilst the indices related to consumptions are kept at their lowest possible level. Based upon a survey on the existing operational optimization and control methodologies, this paper presents a data-driven hybrid intelligent optimal operational control for complex industrial processes and a hybrid simulation system. Simulations and industrial applications to a roasting process for the hematite ore mineral processing industry are used to demonstrate the effectiveness of the proposed method. Issues for future research on the optimal operational control for complex industrial processes are outlined in the final section. © 2012 IFAC.

Lu M.,Northeastern University China
Bio-medical materials and engineering | Year: 2015

Diffusion tensor imaging allows for the non-invasive in vivo mapping of the brain tractography. However, fiber bundles have complex structures such as fiber crossings, fiber branchings and fibers with large curvatures that tensor imaging (DTI) cannot accurately handle. This study presents a novel brain white matter tractography method using Q-ball imaging as the data source instead of DTI, because QBI can provide accurate information about multiple fiber crossings and branchings in a single voxel using an orientation distribution function (ODF). The presented method also uses graph theory to construct the Bayesian model-based graph, so that the fiber tracking between two voxels can be represented as the shortest path in a graph. Our experiment showed that our new method can accurately handle brain white matter fiber crossings and branchings, and reconstruct brain tractograhpy both in phantom data and real brain data.

Tan Y.,Zhejiang GongShang University | Liu S.,Northeastern University China
International Journal of Production Research | Year: 2014

This paper studies the steelmaking-refining-continuous casting (SRCC) scheduling problem with considering variable electricity price (SRCCSPVEP). SRCC is one of the critical production processes for steel manufacturing and energy intensive. Combining the technical rules used in iron-steel production practice, time-dependent electricity price is considered to reduce the electricity cost and the associate production cost. A decomposition approach is proposed for the SRCCSPVEP. Without considering the electrical factor, the first phase applies the mathematical programming method to determine the relative schedule plan for each cast. In the second phase, we formulate a scheduling problem of all casts subject to resource constraint and time-dependent electricity price. A heuristic algorithm combined with the constraint propagation is developed to solve this scheduling problem. To investigate and measure the performance of the proposed approach, numerous instances are randomly generated according to the collective data from a well-known iron-steel plant in China. Computational results demonstrate that our algorithm is very efficient and effective in providing high-quality scheduling plans, and the electricity cost can be reduced for the iron-steel plant. © 2013 Taylor & Francis.

Tang L.,Northeastern University China | Che P.,Northeastern University | Wang J.,Argonne National Laboratory
IEEE Transactions on Power Systems | Year: 2012

We investigate the corrective unit commitment problem to deal with disruption in power system operations caused by an unforeseen unit breakdown with stochastic duration. Since the original unit schedule is no longer feasible when a unit breaks down during operation, a corrective scheduling that provides an immediate response to such a disruption is needed to update the original schedule in time. The objective of the corrective scheduling is to minimize the generation cost and the deviation from the original schedule. The corrective scheduling problem is formulated as a mixed integer nonlinear programming model where the stochastic duration is expressed by tree-structured duration scenarios. The proposed variable splitting-based Lagrangian relaxation algorithm decomposes the problem into multiple single-unit subproblems and a linear programming-type artificial variable subproblem. Each single-unit subproblem is solved by a two-stage procedure. In the first stage, the generating level of the unit in each committed period is determined optimally. In the second stage, before the dynamic programming is called, an effective pre-processing technique based on optimality conditions is applied to speed up the procedure. The dual problem is solved by a bundle method. The numerical results show that the algorithm can find solutions very close to optimums within a reasonable time. © 1969-2012 IEEE.

Jiang X.C.,University of New South Wales | Chen C.Y.,University of New South Wales | Chen C.Y.,Northeastern University China | Chen W.M.,University of New South Wales | Yu A.B.,University of New South Wales
Langmuir | Year: 2010

This study discusses the function of citrate ions in the synthesis of silver nanoplates through a synergetic reduction approach in ambient conditions. It was found that the citrate ions can play multiple roles in the synthesis process, including a reducing agent, a stabilizer, and a complex agent, and they show some unique features under the reported conditions. The reducing ability of these citrate ions was shown to be weaker than that of sodium borohydride and/or L-ascorbic acid used in the same system. The stability in the shape/size control of silver particles is weaker than that of other surfactants tested in the present system, such as bis(2-ethylhexyl)sulfosuccinate (AOT) and thiols. Citrate ions could form a silver complex with silver ions as [Ag2 + ⋯ citrate] or [Ag3(C6H 5O7)n+1]3n-, as confirmed by electrospray ionization (ESI) mass spectrometry and the kinetic analysis that the molar ratio of citric acid or sodium citrate to silver ions can greatly influence the reaction rate and, hence, the particle growth of silver nanoparticles. Such a complexing effect is further confirmed by the use of chelating ions (e.g., [Fe(CN)6]4-) to form Ag n[Fe(CN)6]4-, which can largely influence the synthesis of silver nanoparticles. These results show some formation results of generating silver nanoplates involving citrate ions, which are useful in the shape-controlled synthesis of other metallic nanoparticles with desirable functionalities. © 2010 American Chemical Society.

Luo X.-C.,Northeastern University China
Kongzhi Lilun Yu Yingyong/Control Theory and Applications | Year: 2012

Continuous caster is a machine in which the molten steel is solidified to slabs by spraying on it the cooling water. Nonlinear partial differential equations (PDE) of heat conduction cannot accurately describe the physical process, because of the uncertainties in molten steel temperature and ingredient, and the machine status that causes the variation in arriving time of the next job. Therefore, the optimal set-point values of the caster speed and the cooling water flow-rate are difficult to be determined. In practical industrial plants, those values are given by operators based on the look-up-table method which can not ensure the optimal efficiency and quality of slabs. By considering several operation performance functions and operation constraints, we present an optimal operation set-point model and develop an algorithm based on the genetic algorithm framework using weighted performance functions and central difference method. This model and algorithm are validated in experimental tests with real industrial data. In comparison with the look-up-table method, experimental results show that our method provides better operation set-point values which improve the production efficiency and slab quality.

Zhang Y.,Hefei University of Technology | Xiong Z.,Microsoft | Yang Z.,Northeastern University China | Wu F.,Microsoft
IEEE Transactions on Image Processing | Year: 2014

Time multiplexing (TM) and spatial neighborhood (SN) are two mainstream structured light techniques widely used for depth sensing. The former is well known for its high accuracy and the latter for its low delay. In this paper, we explore a new paradigm of scalable depth sensing to integrate the advantages of both the TM and SN methods. Our contribution is twofold. First, we design a set of hybrid structured light patterns composed of phase-shifted fringe and pseudo-random speckle. Under the illumination of the hybrid patterns, depth can be decently reconstructed either from a few consecutive frames with the TM principle for static scenes or from a single frame with the SN principle for dynamic scenes. Second, we propose a scene-adaptive depth sensing framework based on which a global or region-wise optimal depth map can be generated through motion detection. To validate the proposed scalable paradigm, we develop a real-time (20 fps) depth sensing system. Experimental results demonstrate that our method achieves an efficient balance between accuracy and speed during depth sensing that has rarely been exploited before. © 2013 IEEE.

Wang L.,Northeastern University China
IEEE Transactions on Electron Devices | Year: 2015

To improve the sensitivity and reduce the thickness of the pressure sensor based on conductive polymer composite, a piezoresistive sensor probe with a novel structure called transverse-electrodes-probe (TEP), which is different from the traditional sandwich-structure-probe (SSP), is designed. As the composite and the two electrodes are located in the same layer/three layers of TEP/SSP, TEP is thinner than SSP. The resistivity of TEP increases with the increase in the pressure, contributing to the increasing tendency of the resistance, and the increasing extent of the resistivity of TEP is larger than that of SSP during compression. The uniaxial direction of the electrodes in TEP/SSP is perpendicular/parallel to that of the pressure. Consequently, the thickness of the composite in TEP/SSP is invariant/decreased and the cross-sectional area of the composite in TEP/SSP is decreased/invariant with the increase in the pressure, contributing to the increasing/decreasing trend of the resistance of the composite during compression. The effect of the change in the dimensions on the resistance for TEP/SSP is consistent/opposite with/to the effect of the change in the resistivity. The experimental results verify that the sensitivity of TEP is higher than that of SSP. © 1963-2012 IEEE.

Qiu R.,Northeastern University China | Shang J.,University of Pittsburgh
International Journal of Production Research | Year: 2014

We study robust multi-period inventory decisions for risk-averse managers with incomplete demand information for products with a short life cycle. The three inventory models we developed aim respectively to maximise expected profit, maximise conditional value-at-risk-based profit, and balance between the two objectives. We formulate each objective into an associated robust counterpart model under the assumption of ellipsoid distribution and again under the box distribution. The ellipsoid distribution-based robust model can be mathematically transformed into a non-linear programming which can be solved by finding solutions to some second-order cone programs, while the box distribution-based model can be converted into a general piecewise linear optimisation problem. We prove that the transformed versions are equivalent to the original ones and that both transformed models can be solved efficiently. Numerical examples are given to demonstrate the practicability of the proposed approach for dealing with uncertain demands. We find that the proposed optimisation approaches are robust under both the ellipsoid and box distributions. Finally, sensitivity analysis on the risk-averse degree and optimism index is conducted to validate the proposed models and solution approaches. © 2014 Taylor & Francis.

Lang J.,Northeastern University China
Optics Communications | Year: 2012

In recent years, a number of methods have been proposed in the literature for the encryption of two-dimensional information by using the fractional Fourier transform, but most of their encryptions are complex values and need digital hologram technique to record information, which is inconvenient for digital transmission. In this paper, we propose a new approach for image encryption based on the real-valuedness and decorrelation property of the reality-preserving multiple-parameter fractional Fourier transform in order to meet the requirements of the secure image transmission. In the proposed scheme, the original and encrypted images are respectively in the spatial domain and the reality-preserving multiple-parameter fractional Fourier transformed domain determined by the encryption keys. Numerical simulations are performed to demonstrate that the proposed method is reliable and more robust to blind decryption than several existing methods. © 2012 Elsevier B.V. All rights reserved.

Bai D.,Shenyang University of Chemical Technology | Ren T.,Northeastern University China
Engineering Optimization | Year: 2013

This article addresses the flow shop scheduling problem to minimize the sum of the completion times. On the basis of the properties in job sequencing, the triangular shortest processing time (TSPT) first and dynamic triangular shortest processing time first heuristics are designed to solve the static and dynamic versions of this problem, respectively. Moreover, an improvement scheme is provided for these heuristics to enhance the quality of the original solutions. For further numerical evaluation of the heuristics, two new lower bounds with performance guarantees are presented for the two versions of the problem. At the end of the article, a series of numerical experiments is conducted to demonstrate the effectiveness of the algorithms. © 2013 Taylor & Francis Group, LLC.

Tian Z.-D.,Shenyang University of Technology | Gao X.-W.,Northeastern University China | Shi T.,Liaoning Forestry Vocotion Technical College
Wuli Xuebao/Acta Physica Sinica | Year: 2014

Considering the problem that least squares support vector machine prediction model with single kernel function cannot significantly improve the prediction accuracy of chaotic time series, a combination kernel function least squares support vector machine prediction model is proposed. The model uses a polynomial function and radial basis function to construct the kernel function of least squares support vector machine. An improved genetic algorithm with better convergence speed and precision is proposed for parameter optimization of prediction model. The simulation experimental results of Lorenz, Mackey-Glass, Sunspot-Runoff in the Yellow River and chaotic network traffic time series demonstrate the effectiveness and characteristics of the proposed model. © 2014 Chinese Physical Society

Wang D.,Northeastern University China
Dongbei Daxue Xuebao/Journal of Northeastern University | Year: 2010

In view of the limitations on the conventional evaluation of the technological innovation capability of an enterprise, an evaluation model based on DEA and information entropy was developed for the capability. In the model the evaluation result given by entropy method was combined with the computational result by DEA model to modify the conventional evaluation results reasonably, thus making the modified results available to analyze the output performance from different sizes of input unit comparatively. Computational results showed that the ranking of enterprises, which are obtained from such an evaluation, reflects not only the technological innovation performance of those enterprises but also their input-output efficiency and the validity of their output scale. The ranking of enterprises' technology innovation capability is therefore proved reasonable.

Kobayashi S.,Ashikaga Institute of Technology | Tsurekawa S.,Kumamoto University | Watanabe T.,Northeastern University China | Palumbo G.,Integran Technologies Inc
Scripta Materialia | Year: 2010

Control of brittleness associated with segregation of sulfur to grain boundaries in ultrafine-grained nickel was investigated. The brittleness could be successfully improved by controlling the grain boundary microstructure. The specimens with a higher fraction of special boundaries can have higher fracture toughness even in sulfur-bearing condition. It is evident that grain boundary engineering is applicable to controlling segregation-induced embrittlement in ultrafine-grained materials. © 2009 Acta Materialia Inc.

We present a spatial acquisition scheme based on a fish-eye lens and a sinusoidal amplitude grating that can acquire laser beacons in an ultrawide field of view for atmospheric optical links. In this scheme, an incoming laser beacon can be imaged into three diffraction spots. The laser direction and the wavelength can be measured from the center position of the spots and the distance between two adjacent spots, respectively. The total optical transfer function can be described by the combined effect of the acquisition system itself and the spatial coherence degradation due to atmospheric turbulence. Spot spread and spot dancing effects are both considered for longterm exposure and short-term exposure. We investigate how root mean square errors of the measured laser direction and wavelength vary with the ratio of the pupil diameter D2 to atmospheric coherence length r0, without consideration of aberrations of the fish-eye lens. The results show that with the limitation of r0 the performance cannot be infinitely improved by enlarging D2.When considering aberrations of the fish-eye lens, the imaged spot is gradually blurred and deteriorated with the increase of the field angle, since aberrations are enlarged with the increase of the field angle. We study how the measured errors of laser direction and wavelength vary with r0 and incident angles (with different aberrations). A severe turbulence with a small value of r0 and a large incident angle will cause a bad acquisition performance. © 2015 Optical Society of America.

Fu Y.-H.,Northeastern University China
Dongbei Daxue Xuebao/Journal of Northeastern University | Year: 2010

For a class of evidence fusion problems that integrate different importance with credibility, a new weighted average method based on overall weight of discounted evidence is proposed by combining the static weight with the dynamic weight embodying the similarity between evidences. According to the transcendental information, i.e., static weight and the similarity between evidences, the dynamic weight of evidence is acquired by calculating the distances between all evidences discounted via a static weight computation and their weighted average, then the static weight is integrated with dynamic weight to form an overall weight of evidence. An evidential reasoning model is thus developed with some discount, where the overall weight plays the role as a discounting factor. Finally, the modified evidences are combined together by the weighted average method proposed. A numerical example shows the effectiveness of the method in the integration of those evidences which are in sharp conflict with each other.

Ye D.,Northeastern University China | Zhao X.,CAS Shenyang Institute of Automation
Nonlinear Dynamics | Year: 2014

This paper is concerned with the robust adaptive synchronization problem for a class of chaotic systems with actuator failures and unknown nonlinear uncertainty. Combining adaptive method and linear matrix inequality (LMI) technique, a novel type of robust adaptive reliable synchronization controller is proposed, which can eliminate the effect of actuator fault and nonlinear uncertainty on systems. After solving a set of LMIs, synchronization error between the master chaotic and slave chaotic systems can converge asymptotically to zero. Finally, illustrate examples about chaotic Chua's circuit system and Lorenz systems are provided to demonstrate the effectiveness and applicability of the proposed design method. © 2013 Springer Science+Business Media Dordrecht.

Fan J.,Northeastern University China | Chen J.,Zhejiang University | Du Y.,Zhejiang University | Gao W.,University of Tennessee at Knoxville | And 2 more authors.
IEEE Transactions on Parallel and Distributed Systems | Year: 2013

In this paper, we consider the issue of data broadcasting in mobile social networks (MSNets). The objective is to broadcast data from a superuser to other users in the network. There are two main challenges under this paradigm, namely 1) how to represent and characterize user mobility in realistic MSNets; 2) given the knowledge of regular users' movements, how to design an efficient superuser route to broadcast data actively. We first explore several realistic data sets to reveal both geographic and social regularities of human mobility, and further propose the concepts of geocommunity and geocentrality into MSNet analysis. Then, we employ a semi-Markov process to model user mobility based on the geocommunity structure of the network. Correspondingly, the geocentrality indicating the "dynamic user density" of each geocommunity can be derived from the semi-Markov model. Finally, considering the geocentrality information, we provide different route algorithms to cater to the superuser that wants to either minimize total duration or maximize dissemination ratio. To the best of our knowledge, this work is the first to study data broadcasting in a realistic MSNet setting. Extensive trace-driven simulations show that our approach consistently outperforms other existing superuser route design algorithms in terms of dissemination ratio and energy efficiency. © 1990-2012 IEEE.

Tong Y.,Hong Kong University of Science and Technology | Chen L.,Hong Kong University of Science and Technology | Cheng Y.,Northeastern University China | Yu P.S.,University of Illinois at Chicago
Proceedings of the VLDB Endowment | Year: 2012

In recent years, due to the wide applications of uncertain data, mining frequent itemsets over uncertain databases has attracted much attention. In uncertain databases, the support of an itemset is a random variable instead of a fixed occurrence counting of this itemset. Thus, unlike the corresponding problem in deterministic databases where the frequent itemset has a unique definition, the frequent itemset under uncertain environments has two different definitions so far. The first definition, referred as the expected support-based frequent itemset, employs the expectation of the support of an itemset to measure whether this itemset is frequent. The second definition, referred as the probabilistic frequent itemset, uses the probability of the support of an itemset to measure its frequency. Thus, existing work on mining frequent itemsets over uncertain databases is divided into two different groups and no study is conducted to comprehensively compare the two different definitions. In addition, since no uniform experimental platform exists, current solutions for the same definition even generate inconsistent results. In this paper, we firstly aim to clarify the relationship between the two different definitions. Through extensive experiments, we verify that the two definitions have a tight connection and can be unified together when the size of data is large enough. Secondly, we provide baseline implementations of eight existing representative algorithms and test their performances with uniform measures fairly. Finally, according to the fair tests over many different benchmark data sets, we clarify several existing inconsistent conclusions and discuss some new findings. © 2012 VLDB Endowment.

Sheng B.,Northeastern University China | Li Q.,College of William and Mary | Mao W.,College of William and Mary
Proceedings - IEEE INFOCOM | Year: 2010

RFID is an emerging technology with many potential applications such as inventory management for supply chain. In practice, these applications often need a series of continuous scanning operations to accomplish a task. For example, if one wants to scan all the products with RFID tags in a large warehouse, given a limited reading range of an RFID reader, multiple scanning operations have to be launched at different locations to cover the whole warehouse. Usually, this series of scanning operations are not completely independent as some RFID tags can be read by multiple processes. Simply scanning all the tags in the reading range during each process is inefficient because it collects a lot of redundant data and consumes a long time. In this paper, we develop efficient schemes for continuous scanning operations defined in both spatial and temporal domains. Our basic idea is to fully utilize the information gathered in the previous scanning operations to reduce the scanning time of the succeeding ones. We illustrate in the evaluation that our algorithms dramatically reduce the total scanning time when compared with other solutions. ©2010 IEEE.

Yang J.,Northeastern University China | Yang J.,Arkansas Power Electronics International
Sensors (Switzerland) | Year: 2013

In this article, an extreme environment-capable temperature sensing system based on state-of-art silicon carbide (SiC) wireless electronics is presented. In conjunction with a Pt-Pb thermocouple, the SiC wireless sensor suite is operable at 450 °C while under centrifugal load greater than 1,000 g. This SiC wireless temperature sensing system is designed to be non-intrusively embedded inside the gas turbine generators, acquiring the temperature information of critical components such as turbine blades, and wirelessly transmitting the information to the receiver located outside the turbine engine. A prototype system was developed and verified up to 450 °C through high temperature lab testing. The combination of the extreme temperature SiC wireless telemetry technology and integrated harsh environment sensors will allow for condition-based in-situ maintenance of power generators and aircraft turbines in field operation, and can be applied in many other industries requiring extreme environment monitoring and maintenance. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Yang J.,Northeastern University China | Yang J.,Arkansas Power Electronics International
Sensors (Switzerland) | Year: 2013

Pressure measurement under harsh environments, especially at high temperatures, is of great interest to many industries. The applicability of current pressure sensing technologies in extreme environments is limited by the embedded electronics which cannot survive beyond 300 °C ambient temperature as of today. In this paper, a pressure signal processing and wireless transmission module based on the cutting-edge Silicon Carbide (SiC) devices is designed and developed, for a commercial piezoresistive MEMS pressure sensor from Kulite Semiconductor Products, Inc. Equipped with this advanced high-temperature SiC electronics, not only the sensor head, but the entire pressure sensor suite is capable of operating at 450 °C. The addition of wireless functionality also makes the pressure sensor more flexible in harsh environments by eliminating the costly and fragile cable connections. The proposed approach was verified through prototype fabrication and high temperature bench testing from room temperature up to 450 °C. This novel high-temperature pressure sensing technology can be applied in real-time health monitoring of many systems involving harsh environments, such as military and commercial turbine engines. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Li H.,Northeastern University China | Li H.,University of Aarhus | Thorstenson A.,University of Aarhus
International Journal of Production Research | Year: 2014

Stochastic lot-sizing problems have been addressed quite extensively, but relatively few studies also consider marketing factors, such as pricing. In this paper, we address a joint stochastic lot-sizing and pricing problem with capacity constraints and backlogging for a firm that produces a single item over a finite multi-period planning horizon. Thece-dependent demands. The stochastic demand is captured by the scenario analysis approach, and this leads to a multiple-stage stochastic programming problem. Given the complexity of the stochastic programming problem, it is hard to determine optimal prices and lot sizes simultaneously. Therefore, we decompose the joint lot-sizing and pricing problem with stochastic demands and capacity constraints into a multi-phase decision process. In each phase, we solve the associated sub-problem to optimality. The decomposed decision process corresponds to a practically viable approach to decision-making. In addition to incorporating market uncertainty and pricing decisions in the traditional production and inventory planning process, our approach also accommodates the complexity of time-varying cost and capacity constraints. Finally, our numerical results show that the multi-phase heuristic algorithm solves the example problems effectively. © 2013 Taylor & Francis.

Li G.,Northeastern University China | Wang Y.,China Institute of Technology
Eurasip Journal on Wireless Communications and Networking | Year: 2013

Data aggregation is a very important method to conserve energy by eliminating the inherent redundancy of raw data in wireless sensor networks (WSNs). In this article, we developed an automatic auto regressive-integrated moving averagemodeling-based data aggregation scheme in WSNs. The main idea behind this scheme is to decrease the number of transmitted data values between sensor nodes and aggregators by utilizing time series prediction model. The proposed scheme can effectively save the precious battery energy of wireless sensor nodes while keeping the predicted data values of aggregators within application-defined error threshold. We show through experiments with real data that the predicted data values of our proposed scheme fit the real sensed data values very well and fewer messages are transmitted between sensor nodes and aggregators than the native data aggregation scheme. Furthermore, the characteristics of the proposed data aggregation scheme are also discussed in this article. © 2013 Li and Wang.

Huang M.,Northeastern University China | Lu F.-Q.,Tianjin Polytechnic University | Ching W.-K.,University of Hong Kong | Siu T.K.,Macquarie University
Expert Systems with Applications | Year: 2011

Risk management in a Virtual Enterprise (VE) is an important issue due to its agility and diversity of its members and its distributed characteristics. In this paper, we develop a risk management model for the VE. More specifically, we introduce a Distributed Decision Making (DDM) model for risk management of the VE. The model has two levels, namely, the top model and the base model, which describe the decision processes of the owner and the partners of the VE, respectively. It can be regarded as a combination of both the top-down and bottom-up approaches for risk management of the VE. Here we focus on the case of symmetry information between the owner and the partners. A Particle Swarm Optimization (PSO) algorithm is then designed to solve the resulting optimization problem. The result shows that the proposed algorithm is effective and the two-level model can help improve the description of the relationship between the owner and the partners, which is helpful to reduce the risk of the VE. © 2010 Elsevier Ltd. All rights reserved.

Shi X.,Liaoning University of Petroleum and Chemical Technology | Wei G.,Northeastern University China | Wei G.,CAS Shenyang International Center for Materials Physics
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2010

As an analytical method, the effective-field theory (EFT) is used to study an Ising spin system in a transverse magnetic field under a time oscillating longitudinal field. The effective-field equations of motion of the average magnetization are given for the square lattice (Z = 4). In the longitudinal field amplitude h0 / Z J-transverse field Γ / Z J plane, the phase boundary separating the dynamic ordered and the disordered phase also has been drawn, and there is no dynamical tricritical point on the dynamic phase transition boundary. The dependence of the critical temperature on the transverse field is calculated and phase diagrams are presented. We also make the compare results of EFT with that given by using the mean field theory (MFT). © 2010 Elsevier B.V. All rights reserved.

Hu J.,University of Oxford | Lu X.,University of Oxford | Lu X.,Northeastern University China | Foord J.S.,University of Oxford
Electrochemistry Communications | Year: 2010

The preparation of Pt-modified diamond electrodes by electrodeposition is known to be hampered by poor particle adhesion and a lack of uniformity in the spatial distribution of the deposit over the electrode surface. Here we demonstrate the results can be improved significantly if the electrode is given a simple ultrasonic treatment in the presence of diamond powders prior to electrodeposition. An improvement in spatial distribution and a higher Pt dispersion are seen and, especially, a greater Pt particle stability is observed. Application of these Pt modified diamond electrodes in the electrochemical oxidation of hydrogen peroxide is demonstrated. © 2010 Elsevier B.V. All rights reserved.

Zhang L.,Northeastern University China
Physical Chemistry Chemical Physics | Year: 2016

Deformation is of significance in controlling the shape of materials, but the key structural information of metal nanoparticles is still limited. Molecular dynamics simulations are performed to explore the microscopic details of atom packing differences in three deformed silver nanoparticles with one atom difference. Analytical tools are used to demonstrate the effects of external load and surface atoms of particles on the packing patterns in these deformed nanoparticles including internal energy per atom, pair numbers, and pair distribution functions as well as cross-sectional images. The simulation results show that under small compression, the particles present elastic behaviors. The increasing compression results in the sliding of the atoms in different parts of these particles, and some interfaces are formed between these parts. As the external load becomes large, these deformed particles are compressed into the thickness of several atomic layers. The unloaded particles present different behaviors. © the Owner Societies 2016.

Shi W.,Northeastern University China | Wei W.,Xian Jiaotong University
Journal of Convergence Information Technology | Year: 2011

We modified the multi-agent negotiation test-bed which was proposed by Collins et al. In 2004, Jaiswal et al. have modified Collins's scheme, but Jaiswal's scheme still has some security weaknesses: such as replay data attack and DOS (denial-of-service) attack, anonymity disclosure, collision between customers and a certain supplier. So the proposed protocol tries to reduce DOS attack and avoids replay data attack by providing ticket token and deal sequence number to the supplier. It utilizes efficient LPN-based authentication method to accomplish lightweight authentication. And it publishes an interpolating polynomial for sharing the determination process data and avoids collusion between a customer and a certain supplier. Also the proposed scheme relaxes the trust assumptions for three-party in Jaiswal's scheme. According to comparison and analysis with other protocols, our proposed protocol shows good security and less computation cost.

Chen H.,Harbin Institute of Technology | Zhang E.,Northeastern University China | Yang K.,CAS Shenyang Institute of Metal Research
Materials Science and Engineering C | Year: 2014

In order to improve the biocompatibility and the corrosion resistance in the initial stage of implantation, a phosphate (CaZn2(PO 4)2 · 2H2O) coating was obtained on the surface of pure iron by a chemical reaction method. The anti-corrosion property, the blood compatibility and the cell toxicity of the coated pure iron specimens were investigated. The coating was composed of some fine phosphate crystals and the surface of coating was flat and dense enough. The electrochemical data indicated that the corrosion resistance of the coated pure iron was improved with the increase of phosphating time. When the specimen was phosphated for 30 min, the corrosion resistance (Rp) increased to 8006 Ω. Compared with that of the naked pure iron, the anti-hemolysis property and cell compatibility of the coated specimen was improved significantly, while the anti-coagulant property became slightly worse due to the existence of element calcium. It was thought that phosphating treatment might be an effective method to improve the biocompatibility of pure iron for biomedical application. © 2013 Elsevier B.V.

Ning Z.,Northeastern University China
Applied Mechanics and Materials | Year: 2013

The composition and property of the boron mud is investigated by X-ray diffractometry (XRD), scanning electron microscope (SEM), thermogravimetry (TG), differential thermal analysis (DTA) and fourier transformed infrared spectroscopy (FITR). The mineral components of the boron mud are magnesite (MgCO3), forsterite (Mg2SiO4), hematite (Fe2O3), dolomite (CaMg(CO3)2) and a small amount of magnesium sulfate and lizardite((Mg, Al)3[(Si, Fe)2O5](OH)4)). The decomposition reaction of the boron mud can be carried on at 400~600°C, and silicate of the boron mud can reaction with NaOH with the increase of temperature to about 1000°C. © (2013) Trans Tech Publications, Switzerland.

Cui Y.J.,Northeastern University China
Applied Mechanics and Materials | Year: 2012

This paper presents a modular robot called RBT-6T/S01SM. This robot composed of 6 basic modules which could composed 5 kinds of robot. Each module owns one rotational degree of freedom. The total combined robot RBT-6T/S01SM features an easy-to-build mechanical structure. A formulation of this robot is educed based on Denevit and Hartenberg in this paper. The kinematics is studied and inverse kinematics is obtained based on algebraic method. The kinematics simulation of RBT-6T/S01SM is presented based on Matlab. The effectiveness of kinematics equations is verified by the simulation results. © (2012) Trans Tech Publications.

Yang H.,Ludong University | Zhang Z.,Nanjing Southeast University | Zhang S.,Northeastern University China
International Journal of Robust and Nonlinear Control | Year: 2011

In this paper, the consensus of second-order multi-agent dynamical systems with exogenous disturbances is studied. A pinning control strategy is designed for a part of agents of the multi-agent systems without disturbances, and this pinning control can bring multiple agents' states to reaching an expected consensus track. Under the influence of the disturbances, disturbance observers-based control (DOBC) is developed for disturbances generated by an exogenous system to estimate the disturbances. Asymptotical consensus of the multi-agent systems with disturbances under the composite controller can be achieved for fixed and switching topologies. Finally, by applying an example of multi-agent systems with switching topologies and exogenous disturbances, the consensus of multi-agent systems is reached under the DOBC with the designed parameters. Copyright © 2010 John Wiley & Sons, Ltd.

Li J.-Q.,Liaocheng University | Pan Q.-K.,Liaocheng University | Pan Q.-K.,Northeastern University China
Applied Soft Computing Journal | Year: 2012

This paper proposes an effective discrete chemical-reaction optimization (DCRO) algorithm for solving the flexible job-shop scheduling problems with maintenance activity constraints. Three minimization objectives - the maximum completion time (makespan), the total workload of machines and the workload of the critical machine are considered simultaneously. In the proposed algorithm, each solution is represented by a chemical molecule. Four improved elementary reactions, i.e., on-wall ineffective collision, inter-molecular ineffective collision, decomposition, and synthesis, are developed. A well-designed crossover function is introduced in the inter-molecular collision, synthesis, and decomposition operators. Tabu search (TS) based local search is embedded in DCRO to perform exploitation process. In addition, the decoding mechanism considering the maintenance activity is presented. Several neighboring approaches are developed to improve the local search ability of the DCRO. The proposed algorithm is tested on sets of the well-known benchmark instances. Through the analysis of experimental results, the highly effective performance of the proposed DCRO algorithm is shown against the best performing algorithms from the literature. © 2012 Elsevier B.V. All rights reserved.

Chen Z.,South China Normal University | Yang S.,South China Normal University | Wang Y.,Northeastern University China | Xing D.,South China Normal University
Applied Physics Letters | Year: 2015

We developed and fabricated a noncontact broadband all-optical photoacoustic microscopy (BD-AO-PAM) with a microchip laser and an all-fiber low coherence interferometer. Currently, the available detection bandwidth of the BD-AO-PAM is 67 MHz, and the lateral resolution measured by carbon fibers reaches 11 μm. Furthermore, the imaging capability of the BD-AO-PAM was testified by imaging hairs embedded in scattering gel and in vivo blood vessels of a mouse ear. The experimental results demonstrate that the BD-AO-PAM can image the tissues with high spatial resolution in vivo, which can be used as portable noncontact PAM for biomedical applications. © 2015 AIP Publishing LLC.

Liu T.,Northeastern University China
Fuel Cells | Year: 2013

The cobaltate perovskites Sr1-xDyxCoO 3-δ (SDCO, x = 0.1, 0.2, 0.3) materials were synthesized and evaluated as cathode for La0.8Sr0.2Ga0.8Mg 0.2O3-δ solid electrolyte supported intermediate-temperature-solid oxide fuel cells (IT-SOFCs). The crystal structure of Sr0.9Dy0.1CoO3-δ was defined in the cubic Pm-3m space group (No. 221), Sr0.8Dy 0.2CoO3-δ and Sr0.7Dy 0.3CoO3-δ had a tetragonal I4/mmm structure. The electrical conductivities were all higher than 100 S cm-1 in the temperature of 170-800°C. The polarization resistance (Rp) and its activation energy (Ea) increased with increasing x. SEM analysis confirmed the porous microstructure of the SDCO cathodes and good LSGM|LDC|SDCO adherence. Sr0.9Dy0.1CoO3-δ exhibited the best cathode characteristics with a maximum test-cell power density of 841 mW cm-2, being a high potential candidate of cathode material for IT-SOFCs. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yuan Y.,Northeastern University China | Wang G.,Microsoft | Wang H.,Hong Kong University of Science and Technology | Chen L.,Hubei Engineering University
Proceedings of the VLDB Endowment | Year: 2011

Retrieving graphs containing a query graph from a large graph database is a key task in many graph-based applications, includ-ing chemical compounds discovery, protein complex prediction, and structural pattern recognition. However, graph data handled by these applications is often noisy, incomplete, and inaccurate be-cause of the way the data is produced. In this paper, we study sub-graph queries over uncertain graphs. Specifically, we consider the problem of answering threshold-based probabilistic queries over a large uncertain graph database with the possible world seman-tics. We prove that problem is #P-complete, therefore, we adopt a filtering-and-verification strategy to speed up the search. In the filtering phase, we use a probabilistic inverted index, PIndex, based on subgraph features obtained by an optimal feature selection pro-cess. During the verification phase, we develop exact and bound algorithms to validate the remaining candidates. Extensive experi-mental results demonstrate the effectiveness of the proposed algo-rithms. © 2011 VLDB Endowment.

Xiao C.,University of New South Wales | Wang W.,University of New South Wales | Lin X.,University of New South Wales | Yu J.X.,Chinese University of Hong Kong | Wang G.,Northeastern University China
ACM Transactions on Database Systems | Year: 2011

With the increasing amount of data and the need to integrate data from multiple data sources, one of the challenging issues is to identify near-duplicate records efficiently. In this article, we focus on efficient algorithms to find a pair of records such that their similarities are no less than a given threshold. Several existing algorithms rely on the prefix filtering principle to avoid computing similarity values for all possible pairs of records. We propose new filtering techniques by exploiting the token ordering information; they are integrated into the existing methods and drastically reduce the candidate sizes and hence improve the efficiency. We have also studied the implementation of our proposed algorithm in stand-alone and RDBMSbased settings. Experimental results show our proposed algorithms can outperform previous algorithms on several real datasets. © 2011 ACM.

Yu H.,University of Wollongong | Liu X.,Shenyang University | Li X.,Northeastern University China | Godbole A.,University of Wollongong | Godbole A.,Baosteel
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2014

The behavior of internal crack healing in low-carbon steel samples undergoing hot plastic deformation was investigated using the MMS 200 thermo-mechanical simulator. The characterization of cracks after plastic deformation was analyzed using scanning electron microscopy under different heating temperatures, reduction ratios, numbers of deformation passes, strain rates, and holding time durations. It was found that the degree of crack healing increases with increasing heating temperature, reduction ratio, and holding time duration, and with decreasing number of deformation passes and strain rate. © The Minerals, Metals & Materials Society and ASM International 2013.

Liu Y.,Northeastern University China | Cheng Z.,Tsinghua University | Sun H.,Tsinghua University | Arandiyan H.,University of New South Wales | And 2 more authors.
Journal of Power Sources | Year: 2015

(Graph Presented). Co3O4 mesoporous nanosheets/three-dimensional graphene networks (Co3O4 MNSs/3DGNs) nanohybrids have been successfully synthesized and investigated as anode materials for sodium ion batteries (SIBs). Microstructure characterizations have been performed to confirm the 3DGNs and Co3O4 MNSs nanostructures. It has been found that the present Co3O4 MNSs/3DGNs nanohybrids exhibit better SIB performance with enhanced reversible capacity, good cycle performance and rate capability as compared to Co3O4 MNSs and Co3O4 nanoparticles. The improved electrochemical performance is considered due to the mesoporous nature of the products, the addition of 3DGNs, 3D assembled hierarchical architecture and decrease in volume expansion during cycling. Thus, SIB is considered as a low cost alternative to LIBs for large-scale electric storage applications. © 2014 Elsevier B.V. All rights reserved.

Xu J.,Northeastern University China | Haarberg G.M.,Norwegian University of Science and Technology
High Temperature Materials and Processes | Year: 2013

Silicon is the most common material used in solar cells. High cost of silicon restricts the widely use of PV power. In order to make solar cells more accessible and affordable, it is strongly needed to develop a new and low-cost production process of solar energy silicon (SoG-Si). Electrodeposition of SoG-Si films appears to be a cost saving technique since solidification and sawing steps which contribute significantly to the overall cost of solar cells will be bypassed. Electrodeposition of SoG-Si has been evaluated during the last three decades, and some of them have shown promising results. Thermodynamic and kinetic considerations which relate to the electrodeposition of silicon are discussed, and progresses towards the developments of the electrodeposition of silicon in high temperature molten salts are reviewed in this paper. Copyright © 2013 De Gruyter.

Li R.,Northeastern University China | Khalil H.K.,Michigan State University
Proceedings of the IEEE Conference on Decision and Control | Year: 2012

In this paper we propose a conditional integrator for solving the regulation problem of a class of nonlinear systems that probably possess unstable zero dynamics. The control scheme mainly takes advantage of the auxiliary controller proposed in [3] and a slow integrator. We present that the solution of the regulation problem can be cast as two auxiliary problems. Furthermore it is shown that the design of the conditional integrator requires the design of a feedback control that solves two stabilization problems simultaneously, one inside the boundary layer of a continuously-implemented sliding model control, and one outside it. Hence the design of the auxiliary controller can be independent of the internal model. We approach this issue by using a two-time-scale method. The effectiveness of the controller is illustrated through a linear example. © 2012 IEEE.

Liu T.,Northeastern University China | Liu T.,University of Texas at Austin | Li Y.,University of Texas at Austin | Li Y.,Heilongjiang University | Goodenough J.B.,University of Texas at Austin
Journal of Power Sources | Year: 2012

The oxygen-deficient perovskite Sr0.7Ho0.3CoO 3-δ (SHCO) operates on the Co(III)/Co(II) redox couple rather than the usual Co(IV)/Co(III) couple for an oxygen reduction reaction(ORR) cathode of an intermediate-temperature solid oxide fuel cell (IT-SOFC). The room-temperature XRD pattern of SHCO prepared by solid-state reaction can be indexed in the tetragonal I4/mmm space group with unit-cell parameters a = 7.617 , and c = 15.293 . SHCO exhibits an electrical conductivity with values larger than 488 S cm-1 over the temperature range 560-800 °C. The area specific resistance (ASR) of a SHCO cathode measured on a La 0.8Sr0.2Ga0.83Mg0.17O 2.815 (LSGM) electrolyte reaches a relatively low value of 0.14 Ω cm2 at 800 °C in air. With a 300-μm-thick LSGM disk as the electrolyte and NiO-GDC as the anode, a cell with the SHCO cathode exhibited maximum power densities of 1274, 756, and 493 mW cm-2 at 850, 800, and 750 °C, respectively, with hydrogen as fuel and ambient air as oxidant. Cross-section scanning-electron-microscopy measurements confirmed the porous microstructure of the electrodes and good electrode-buffer layer-electrolyte adherence in a single test cell. The ORR activity of a SHCO cathode operating on the Co(III)/Co(II) couple approaches that of the best cathodes operating on the Co(IV)/Co(III) couple, and higher-spin Co(III) ions provide a compatible thermal expansion. © 2011 Elsevier B.V. All rights reserved.

Wang J.,Macau University of Science and Technology | Wang C.-H.,National Chiao Tung University | Wang C.-H.,Northeastern University China | Chen C.L.P.,Macau University of Science and Technology
IEEE Transactions on Fuzzy Systems | Year: 2014

In this paper, a fuzzy neural network (FNN) is transformed into an equivalent three-layer fully connected neural inference system (F-CONFIS). This F-CONFIS is a new type of a neural network whose links are with dependent and repeated weights between the input layer and hidden layer. For these special dependent repeated links of the F-CONFIS, some special properties are revealed. A new learning algorithm with these special properties is proposed in this paper for the F-CONFIS. The F-CONFIS is therefore applied for finding the capacity of the FNN. The lower bound and upper bound of the capacity of the FNN can be found from a new theorem proposed in this paper. Several examples are illustrated with satisfactory simulation results for the capacity of the F-CONFIS (or the FNN). These include "within capacity training of the FNN," "over capacity training of the FNN, " "training by increasing the capacity of the FNN," and "impact of the capacity of the FNN in clustering Iris Data." It is noted that the finding of the capacity of the F-CONFIS, or FNN, has its emerging values in all engineering applications using fuzzy neural networks. This is to say that all engineering applications using FNN should not exceed the capacity of the FNN to avoid unexpected results. The clustering of Iris data using FNN illustrated in this paper is one of the most relevant engineering applications in this regards. © 2014 IEEE.

Wang G.,University of California at Santa Cruz | Ling Y.,University of California at Santa Cruz | Qian F.,University of California at Santa Cruz | Yang X.,University of California at Santa Cruz | And 2 more authors.
Journal of Power Sources | Year: 2011

We report for the first time the enhanced capacitance of multi-walled carbon nanotubes (MWCNTs) after exfoliation. Transmission electron microscopy studies confirmed that the MWCNTs were partially exfoliated with improved effective surface area. Carbon cloth electrode deposited with partially exfoliated carbon nanotubes (Ex-CNTs) yielded specific capacitances in a range of 130-165 F g-1 at charging/discharging current densities from 5 to 0.5 A g-1, with coulombic efficiencies of ∼98%. The specific capacitance of Ex-CNTs was an order of magnitude higher than untreated MWCNTs, and comparable to graphene at all charging/discharging current densities we studied. The enhanced capacitance can be attributed to improved effective surface area and increased defect density of the exfoliated tubular structure. The results declared that Ex-CNTs are promising electrode materials for high-capacitance supercapacitors. © 2011 Elsevier B.V.

Gao S.Z.,Shenyang University of Chemical Technology | Wang J.S.,University Of Science And Technology Liaoning | Gao X.W.,Northeastern University China
Journal of Process Control | Year: 2013

Based on data driven modeling theory, PVC polymerization process modeling and intelligent optimization control algorithm is studied. Firstly, a multi-T-S fuzzy neural networks soft-sensing model combining the principal component analysis (PCA) and fuzzy c-means (FCM) clustering algorithm is proposed to predict the convention rate and velocity of Vinyle Chloride Monomer (VCM). The proposed hybrid learning algorithm utilizing the harmony search (HS) and least square method is used to adjust the model premise parameters and consequent parameters. Secondly, the generalized predictive control (GPC) algorithm of polymerizer temperature based on segmental affine is proposed. According to dynamic equation of polymerizer temperature deduced by heat balance mechanism, the segmental affine model is built by temperature and convention rate of the polymerizer. Then linear matrix inequality (LMI) method is used to design the controller. Finally, simulation results and industrial application show the validity and feasibility of the proposed control strategy. © 2013 Elsevier Ltd. All rights reserved.

Wang J.-W.,Northeastern University China
Modern Physics Letters B | Year: 2012

The network disaster induced by cascading failures has traumatized modern societies. How to protect these networks and improve their robustness against cascading failures has become the key issue. To this end, we construct a cascading model and propose an efficient mitigation strategy against cascading failures. In many real-world networks, there exist some heterogeneous nodes, for example the hosts and the routers in the Internet, and the users and the supply-grid stations in the power grid. In previous studies, however, less cascading models were constructed to describe such fact. Including two types of nodes in a network, we present a new cascading model. We introduce a new mitigation strategy with dynamically adjusting the load and demonstrate its efficiency on the BarabásiAlbert (BA) network and the power grid as well as the Internet. We show that with small changes in dynamically adjusting the load the robustness of these networks can be improved dramatically. Our results are useful not only for protecting networks from the local perspective, but also for significantly improving the robustness of the existing infrastructure networks. © 2012 World Scientific Publishing Company.

Feng B.,South China University of Technology | Fan Z.-P.,Northeastern University China | Li Y.,City University of Hong Kong
International Journal of Production Economics | Year: 2011

Although supplier selection in multi-service outsourcing is a very important decision problem, research concerning this issue is still relatively scarce. This paper proposes a decision method for selecting a pool of suppliers for the provision of different service process/product elements. It pioneers the use of collaborative utility between partner firms for supplier selection. A multi-objective model is built to select desired suppliers. This model is proved to be NP-hard, so we develop a multi-objective algorithm based on Tabu search for solving it. We then use an example to show the applicability of the proposed model and algorithm. Extensive computational experiments are also conducted to further test the performance of the proposed algorithm. © 2011 Elsevier B.V. All rights reserved.

Li H.,CAS Institute of High Energy Physics | Li H.,Chinese Academy of Sciences | Zhang X.,Northeastern University China | Zhang X.,Peking University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

The CPL parametrization is very important for investigating the property of dark energy with observational data. However, the CPL parametrization only respects the past evolution of dark energy but does not care about the future evolution of dark energy, since w(z) diverges in the distant future. In a recent paper [J.Z. Ma, X. Zhang, Phys. Lett. B 699 (2011) 233], a robust, novel parametrization for dark energy, w(z)=w0+w1(ln(2+z)/1+z-ln2), has been proposed, successfully avoiding the future divergence problem in the CPL parametrization. On the other hand, an oscillating parametrization (motivated by an oscillating quintom model) can also avoid the future divergence problem. In this Letter, we use the two divergence-free parametrizations to probe the dynamics of dark energy in the whole evolutionary history. In light of the data from 7-year WMAP temperature and polarization power spectra, matter power spectrum of SDSS DR7, and SN Ia Union2 sample, we perform a full Markov Chain Monte Carlo exploration for the two dynamical dark energy models. We find that the best-fit dark energy model is a quintom model with the EOS across -1 during the evolution. However, though the quintom model is more favored, we find that the cosmological constant still cannot be excluded. © 2011 Elsevier B.V.

Zhang Y.,Northeastern University China
Shock and Vibration | Year: 2011

On the basis of the Bouc-Wen hysteretic model, the effective numerical method for the response of nonlinear multi-degree-of-freedom (MDOF) stochastic hysteretic systems is presented using second moment method. Using this method, the mean values, variances and covariances are computed. The Monte Carlo simulation is applied to validate the method. The results obtained by the two methods are contrasted, and the solutions of the method in this paper agreed very well with the Monte Carlo simulation. It has solved the random response of nonlinear stochastic vibration systems which is caused by the stochastic hysteretic loop itself. © 2011 - IOS Press and the authors. All rights reserved.

Yang Y.,Northeastern University China | Chen J.,Hainan Litree Purifying Technology Co.
Advanced Materials Research | Year: 2013

Advanced treatment of drinking water was performed by ultrafiltration process (UF) in this study. Experimental results showed that UF is a perfect physical sieving barrier to remove turbidity, algae and bacteria from water, which is far superior to conventional water treatment processes. But the ultrafiltration membrane is not very effective for the removal of dissolved organic matter because of the large molecular weight cut-off. And the backwashing per 30min can totally renew the ultrafiltration membrane. © (2013) Trans Tech Publications, Switzerland.

Jiang F.,Northeastern University China
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi | Year: 2012

Based on the fact that the respiratory component modulates the cardiac cycle component in the ballistocardiogram (BCG) signal, we propose a method that detects respiratory with time-frequency analysis for the sitting ballistocardiography system. Firstly, we demodulated the BCG signal by using the variable frequency complex demodulation (VFCDM) to obtain the output for different center frequency of interest. Then we calculated the instantaneous frequencies and the instantaneous amplitudes by the time-frequency representation. We reconstructed the time-domain waveform of respiratory at last. In order to verify the feasibility and accuracy of this method, we applied wavelet transform and nasal thermistor signal to compare qualitatively and quantitatively. The simulation results showed that the proposed method could detect the respiratory rate from BCG signal more accurately, which provided meaningful attempt for monitoring the multiple physiological parameters synchronously and unconsciously.

Kobayashi S.,Ashikaga Institute of Technology | Maruyama T.,Ashikaga Institute of Technology | Tsurekawa S.,Kumamoto University | Watanabe T.,Northeastern University China | Watanabe T.,Tohoku University
Acta Materialia | Year: 2012

The effect of grain boundary microstructure on the fracture resistance of sulfur-doped polycrystalline nickel was investigated using specimens with different grain boundary microstructures to reveal the usefulness of grain boundary engineering for control of segregation-induced intergranular brittle fracture of polycrystalline materials. The sulfur-doped polycrystalline nickel specimen with more homogeneous fine-grained structure and a higher fraction of low-Σ coincidence site lattice (CSL) boundaries shows higher fracture resistance than the specimen with coarse-grained structure and a lower fraction of low-Σ CSL boundaries. It was found that high-energy random boundaries play a key role as the preferential crack path in fracture processes. The resistance to sulfur segregation-induced intergranular brittle fracture was evaluated by analyzing the fractal dimension of random boundary connectivity in the polycrystalline nickel specimens studied. The fractal dimension of random boundary connectivity decreases with increasing fraction of low-Σ CSL boundaries, resulting in the generation of a higher fracture resistance by restricting more frequent branching and deflection of propagating crack path along random boundaries from the main crack. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Wang Y.Q.,Northeastern University China
Nonlinear Dynamics | Year: 2014

In this paper, the large-amplitude (geometrically nonlinear) vibrations of rotating, laminated composite circular cylindrical shells subjected to radial harmonic excitation in the neighborhood of the lowest resonances are investigated. Nonlinearities due to large-amplitude shell motion are considered using the Donnell's nonlinear shallow-shell theory, with account taken of the effect of viscous structure damping. The dynamic Young's modulus which varies with vibrational frequency of the laminated composite shell is considered. An improved nonlinear model, which needs not to introduce the Airy stress function, is employed to study the nonlinear forced vibrations of the present shells. The system is discretized by Galerkin's method while a model involving two degrees of freedom, allowing for the traveling wave response of the shell, is adopted. The method of harmonic balance is applied to study the forced vibration responses of the two-degrees-of-freedom system. The stability of analytical steady-state solutions is analyzed. Results obtained with analytical method are compared with numerical simulation. The agreement between them bespeaks the validity of the method developed in this paper. The effects of rotating speed and some other parameters on the nonlinear dynamic response of the system are also investigated. © 2014 Springer Science+Business Media Dordrecht.

Misra R.D.K.,University of Texas at El Paso | Challa V.S.A.,University of Texas at El Paso | Venkatsurya P.K.C.,ArcelorMittal | Shen Y.F.,Northeastern University China | And 2 more authors.
Acta Materialia | Year: 2015

The concept of phase reversion involving severe cold deformation of austenite at room temperature to generate strain-induced martensite, followed by annealing when martensite reverts to austenite via a diffusional mechanism, was used to obtain a "high strength, high ductility" combination in nanograined (NG) austenitic stainless steel. Using this concept, the objective of the study is to elucidate the dependence of grain size on deformation mechanisms and deformation-induced microstructural changes. The objective was accomplished by combining depth-sensing nanoindentation experiments conducted at strain rates spanning two orders of magnitude and post-mortem analyses of deformed Fe-17Cr-7Ni austenite alloy using transmission electron microscopy. The strain-rate sensitivity of the NG structure (0.13) was about twice the coarse-grained (CG) counterpart (0.06) and the activation volume was about one-third (16b3) of the CG structure (48b3), where b is the magnitude of the Burgers vector. In the high strength NG steel, deformation twinning contributed to excellent ductility, while in the low strength CG steel, ductility was also good, but due to strain-induced martensite, implying clear distinction and fundamental transition in the deformation behavior of NG and CG Fe-17Cr-7Ni austenitic stainless steels. In the NG structure, there was marked increase in stacking faults and twin density at high strain rates, which led to a decrease in the average spacing between adjacent stacking faults, converting stacking faults into twins. The plastic zone in the NG structure resembled a network knitted by the intersecting twins and stacking faults. The observed change in the deformation mechanism with change in grain size is attributed to increased stability of austenite with a decrease in grain size, and is explained in terms of the austenite stability-strain energy relationship. © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Wang C.,Northeastern University China
Advances in Engineering Software | Year: 2014

This paper presents an integrated approach for aerodynamic blade design in an MDO (multidisciplinary design optimization) environment. First, requisite software packages and data sources for flow computations and airfoil modeling are integrated into a single cybernetic environment, which significantly enhances their interoperability. Subsequently, the aerodynamic blade design is implemented in a quasi-3D way, supported by sophisticated means of project management, task decomposition and allotment, process definition and coordination. Major tasks of aerodynamic blade design include 1D meanline analysis, streamsurface computations, generation of 2D sections, approximation of 3D airfoils, and 3D flow analysis. After compendiously depicting all the major design/analysis tasks, this paper emphatically addresses techniques for blade geometric modeling and flow analysis in more detail, with exemplar application illustrations. © 2013 Elsevier Ltd. All rights reserved.

Jiang S.-F.,Fuzhou University | Zhang C.-M.,Northeastern University China | Zhang S.,Shenyang Jianzhu University
Expert Systems with Applications | Year: 2011

It is proposed in this paper a novel two-stage structural damage detection approach using fuzzy neural networks (FNNs) and data fusion techniques. The method is used for structural health monitoring and damage detection, particularly for cases where the measurement data is enormous and with uncertainties. In the first stage of structural damage detection, structural modal parameters derived from structural vibration responses are fed into an FNN as the input. The output values from the FNN are defuzzified to produce a rough structural damage assessment. Later, in the second stage, the values output from three different FNN models are input directly to the data fusion center where fusion computation is performed. The final fusion decision is made by filtering the result with a threshold function, hence a refined structural damage assessment of superior reliability. The proposed approach has been applied to a 7-degree of freedom building model for structural damage detection, and proves to be feasible, efficient and satisfactory. Furthermore, the simulation result also shows that the identification accuracy can be boosted with the proposed approach instead of FNN models alone. © 2010 Elsevier Ltd. All rights reserved.

Wang C.,Northeastern University China
Computers in Industry | Year: 2014

This paper presents technical insights gained from developing a multidisciplinary design and analysis (MDA) environment, which proficiently integrates, coordinates and controls disciplinary software packages, data sources, and human factors. The MDA environment cost-effectively boosters global optimization of product design problems by means of integrating and coordinating engineering resources, implementing optimization approaches, and reconciling contradicting disciplinary objectives. This paper begins with depicting a multidisciplinary view of a generic complex engineering system, which sets the basic tone of developments of the environment. Subsequently, this paper proceeds with descriptions of information techniques or software utilities that constitute core competencies of the MDA environment. Firstly, software components based integration techniques are implemented to enhance interoperability among heterogeneous engineering applications and data sources. The integration techniques have viably overcome engineering inefficiencies, system incongruences, and information inconsistencies caused by 'automation islands' problems. Secondly, project and workflow management utilities are developed to support collaborative design, which allows better utilization of engineering resources and effective coordination. Thirdly, tailored geometry modeling techniques are implemented to enable expeditious representations of shape variations in congruence with outcomes of multiphysics analyses and simulations. Fourthly, optimization strategies, sensitivity analysis, surrogate models and searching algorithms are coded to enable global engineering optimization. Finally, this paper concludes with insights gained from developments of the MDA infrastructure. © 2014 Elsevier B.V.

Zhu L.-Y.,Northeastern University China
2010 3rd International Symposium on Knowledge Acquisition and Modeling, KAM 2010 | Year: 2010

Knowledge service vendor selection is an important task for the decision makers of the company in the knowledge economics. The purpose of this study is to investigate a fuzzy multiple criteria decision-making method for evaluating and selecting knowledge service vendor. In the paper, the multiple criteria should consider in the evaluation and selection process is presented. Then, a fuzzy MCDM approach based on fuzzy TOPSIS is proposed. The linguistic evaluation information given by the decision makers are transformed into the form of triangular fuzzy numbers. Based on the extended TOPSIS, the fuzzy positive-ideal solution (FPIS) and the fuzzy negative-ideal solution (FNIS) are determined. The relative closeness of each alternatives to the FPIS and FNIS is calculated to determine the ranking order of all alternatives. The evaluation results of the knowledge service providers can be obtained through the proposed fuzzy method and then the proper vendor can be selected. Additionally, an illustrating example is given to show the feasibility and practicability of the proposed approach. © 2010 IEEE.

Zhang Y.,Northeastern University China
Frontiers of Mechanical Engineering | Year: 2015

The reliability-based design optimization, the reliability sensitivity analysis and robust design method are employed to present a practical and effective approach for reliability-based robust design optimization of vehicle components. A procedure for reliability-based robust design optimization of vehicle components is proposed. Application of the method is illustrated by reliability-based robust design optimization of axle and spring. Numerical results have shown that the proposed method can be trusted to perform reliability-based robust design optimization of vehicle components. © 2015, Higher Education Press and Springer-Verlag Berlin Heidelberg.

Shi W.,Northeastern University China | Gong P.,Beijing Institute of Technology
International Journal of Distributed Sensor Networks | Year: 2013

User authentication in wireless sensor networks (WSNs) is a critical security issue due to their unattended and hostile deployment in the field. Since sensor nodes are equipped with limited computing power, storage, and communication modules, authenticating remote users in such resource-constrained environments is a paramount security concern. To overcome the weaknesses of Yeh et al.'s protocol, we proposed a new authentication protocol for wireless sensor networks using elliptic curves cryptography. The comparisons show that our protocol is more suitable for WSNs. © 2013 Wenbo Shi and Peng Gong.

Min X.,Japan National Institute of Materials Science | Sawaguchi T.,Japan National Institute of Materials Science | Zhang X.,Northeastern University China | Tsuzaki K.,Japan National Institute of Materials Science | Tsuzaki K.,University of Tsukuba
Scripta Materialia | Year: 2012

Quantitative surface relief analysis proved that the incomplete shape recovery of a polycrystalline Fe-28Mn-6Si-5Cr alloy was not caused by slip deformation on loading but by irreversible phase transformation on heating, under given conditions ([54̄1̄] tensile axis, 5.9% strain). The observed area showed a higher recovery strain than the macroscopic recovery strain, implying inherently high reversibility. However, the value was significantly lower than that of a single crystal, due to the geometric constraint from surrounding grains, which reflected different transformation dislocations between forward and reverse transformations. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Long L.,Northeastern University China | Zhao J.,Australian National University
IEEE Transactions on Automatic Control | Year: 2012

The problem of H \∞ control of switched nonlinear systems in p-normal form is investigated in this technical note where the solvability of the H \∞ control problem for individual subsystems is unnecessary. Using the generalized multiple Lyapunov functions method and the adding a power integrator technique, we design a switching law and construct continuous state feedback controllers of subsystems explicitly by a recursive design algorithm to produce global asymptotical stability and a prescribed H \∞ performance level. Multiple Lyapunov functions are exploited to reduce the conservativeness caused by adoption of a common Lyapunov function for all subsystems, which is usually required when applying the backstepping-like recursive design scheme. An example is provided to demonstrate the effectiveness of the proposed design method. © 2012 IEEE.

Zhao J.,Northeastern University China | Hill D.J.,University of Sydney | Liu T.,Australian National University
IEEE Transactions on Automatic Control | Year: 2012

This note addresses the problem of synchronization for general dynamical networks with nonidentical nodes. The coupling strength, outer coupling configuration and inner connection in such networks are all time varying. Neither an equilibrium for each node nor a synchronization manifold is assumed to exist. An estimate of the convergence domain for a general class of time-varying nonlinear systems is given. By introducing the average dynamics of all nodes and based on this estimate, a criterion of global synchronization in the sense of boundedness of the maximum state deviation between nodes is developed. An explicit bound of the maximum state deviation between nodes is obtained by the maximum difference between each node dynamics and the average dynamics. The proposed criterion is an extension of several related synchronization criteria for the case of identical nodes to the case of nonidentical nodes. © 2012 IEEE.

Zhang B.,University of Texas at Austin | Zhang B.,Northeastern University China | Lee W.H.,University of Texas at Austin | Piner R.,University of Texas at Austin | And 5 more authors.
ACS Nano | Year: 2012

A two-step CVD route with toluene as the carbon precursor was used to grow continuous large-area monolayer graphene films on a very flat, electropolished Cu foil surface at 600 °C, lower than any temperature reported to date for growing continuous monolayer graphene. Graphene coverage is higher on the surface of electropolished Cu foil than that on the unelectropolished one under the same growth conditions. The measured hole and electron mobilities of the monolayer graphene grown at 600 °C were 811 and 190 cm 2/ (V·s), respectively, and the shift of the Dirac point was 18 V. The asymmetry in carrier mobilities can be attributed to extrinsic doping during the growth or transfer. The optical transmittance of graphene at 550 nm was 97.33%, confirming it was a monolayer, and the sheet resistance was ∼8.02 × 10 3 δ/□. © 2012 American Chemical Society.

Yang Q.,Northeastern University China
Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument | Year: 2011

Biomass is hard to be measured on-line in real-time in fermentation process, which brings difficulty in process control and optimization. To solve this problem, soft sensor technique is applied to implement the on-line estimation of biomass, and an improved series hybrid modeling method is presented to develop the soft sensor model of biomass in fermentation process. The improved series hybrid modeling method overcomes the shortcoming that existing method requires using the data obtained through interpolation to develop the soft sensor model, and guarantees the reliability of the modeling data. Simulation is performed using the production data from Nosiheptide fermentation process. Simulation results show that the soft sensor model based on the improved series hybrid modeling method is effective and has better estimation performance than the soft sensor model based on existing method.

Jia T.,University of British Columbia | Jia T.,Northeastern University China | Militzer M.,University of British Columbia
ISIJ International | Year: 2012

A unified model is proposed for the austenite-to-ferrite transformation kinetics in binary Fe-Mn alloys that accounts for solute drag of Mn. To aid the model development, continuous cooling transformation (CCT) tests were conducted for an interstitial-free steel that can be considered as Fe-0.1%Mn alloy. The experimental transformation data are supplemented with literature data for Fe-1%Mn and Fe-2%Mn alloys to establish a CCT database for Fe-Mn alloys. The austenite-to-ferrite transformation kinetics is described from a fundamental perspective by assuming an interface-controlled reaction and including solute drag of Mn. Using the solute drag model of Fazeli and Militzer, intrinsic interface mobility, trans-interface diffusivity of Mn and its binding energy have been determined from the CCT data. The interfacial parameters are critically analyzed and compared with independent measurements of diffusion and grain boundary segregation. © 2012 ISIJ.

Tian Y.,Northeastern University China | Li Z.,Shenyang Institute of Engineering
Journal of Iron and Steel Research International | Year: 2012

Warm deformation tests were performed using a kind of tubby heater. The microstructures and mechanical properties of an Fe-C-Mn-Si multiphase steel resulting from different warm deformation temperatures were investigated by using LOM (light optical microscopy), SEM and XRD. The results indicated that the microstructure containing polygonal ferrite, granular bainite and a significant amount of the stable retained austenite can be obtained through hot deformation and subsequent austempering. Warm deformation temperature affects the mechanical properties of the hot rolled TRIP steels. Ultimate tensile strength balance reached maximum (881 MPa) when the specimen was deformed at 250°C, and the total elongation and strength-ductility reached maximum (38% and 28614 MPa · %, respectively) at deforming temperature of 100°C. Martensite could nucleate when austenite was deformed above M 3, because mechanical driving force compensates the decrease of chemical driving force. The TRIP effect occurs in the Fe-C-Mn-Si multiphase steel at deforming temperature ranging from 15 to 350°C. The results of the effects of warm deformation on the mechanical properties of the Fe-C-Mn-Si multiphase steel can provide theoretical basis for the applications and the warm working of the hot rolled TRIP sheet steels in industrial manufacturing. © 2012 Central Iron and Steel Research Institute.

Lang J.,Northeastern University China
Optics and Lasers in Engineering | Year: 2012

In recent years, a number of methods have been proposed in the literature for the encryption of two-dimensional information by use of the fractional Fourier transform, but most of their encryptions are complex value and need digital hologram technique to record their encrypted information, which is inconvenience for digital transmission. In this paper, we first propose a novel reality-preserving multiple-parameter fractional Fourier transform which share real-valuedness outputs as well as most of the properties required for a fractional transform. Then we propose a new approach for image encryption based on the real-valuedness of the reality-preserving multiple-parameter fractional Fourier transform and the decorrelation property of chaotic maps in order to meet the requirements of the secure image transmission. In the proposed scheme, the image is encrypted by juxtaposition of sections of the image in the reality-preserving multiple-parameter fractional Fourier domains and the alignment of sections is determined by chaotic logistic maps. Numerical simulations are performed to demonstrate that the proposed method is reliable and more robust to blind decryption than several existing methods. © 2012 Elsevier Ltd. All rights reserved.

Lu L.,Shanghai JiaoTong University | Lu L.,TU Eindhoven | Lu L.,Northeastern University China | Lin Z.,University of Virginia
IEEE Transactions on Automatic Control | Year: 2011

This technical note revisits the problem of designing a static anti-windup gain for enlarging the domain of attraction of the resulting closed-loop system. By utilizing a composite quadratic Lyapunov function, which was originally proposed to study the stabilization problem for linear systems under actuator saturation, an existing LMI based design algorithm is enhanced to result in a nonlinear, possibly continuous, anti-windup gain. This nonlinear anti-windup gain enables us to obtain an estimate of the domain of attraction in the form of the convex hull of a group of ellipsoids, instead of a single ellipsoid that would result from a single Lyapunov function based design. Simulation results demonstrate the features of the proposed design the composite quadratic Lyapunov function brings about. © 2006 IEEE.

Yang G.-H.,Northeastern University China | Wang H.,Beijing University of Technology | Xie L.,Nanyang Technological University
International Journal of Robust and Nonlinear Control | Year: 2010

The paper studies the fault detection problem for output feedback control systems with bounded disturbances and nonzero constant reference inputs. A steady-state-based approach is proposed which can be used to detect small actuator stuck faults including actuator outage (the stuck value is zero). These small stuck faults, especially the outage faults, cannot be detected effectively using the existing techniques. A dynamic output feedback controller and a weighting matrix are designed simultaneously. The dynamic output feedback controller stabilizes the closed-loop system for both fault-free and faulty cases and attenuates the effects of disturbances. By manipulating the steady-state values of system states with the detection weighting matrix, a residual is then generated, through which actuator stuck faults including actuator outages can be detected effectively. Simulation results are included to demonstrate our design procedure. Copyright © 2009 John Wiley & Sons, Ltd.

Chang X.-H.,Bohai University | Chang X.-H.,Shenyang University | Yang G.-H.,Northeastern University China
IEEE Transactions on Industrial Electronics | Year: 2014

This paper is concerned with the problem of nonfragile H filtering for continuous-time Takagi-Sugeno (T-S) fuzzy systems. The filter to be designed is assumed to have two types of multiplicative gain variations. First, two relaxed H filtering analysis conditions are proposed based on useful linear matrix inequality preliminaries. Whereafter, the results are exploited to derive sufficient conditions for designing a nonfragile H filter, which guarantees a prescribed H performance of the filtering error system. Compared with the existing results, the proposed design methods not only suit for a standard form of the fuzzy filter but also give more relaxed design conditions. Finally, simulation examples will be given to show the efficiency of the proposed design methods. © 2013 IEEE.

Li H.,CAS Institute of High Energy Physics | Li H.,CAS National Astronomical Observatories | Zhang X.,Northeastern University China | Zhang X.,Peking University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

In this Letter, we report the results of constraining the dynamical dark energy with a divergence-free parameterization, in the presence of spatial curvature and massive neutrinos, with the 7-yr WMAP temperature and polarization data, the power spectrum of LRGs derived from SDSS DR7, the Type Ia supernova data from Union2 sample, and the new measurements of H 0 from HST, by using a MCMC global fit method. Our focus is on the determinations of the spatial curvature, Ω k, and the total mass of neutrinos, ∑m ν, in such a dynamical dark energy scenario, and the influence of these factors to the constraints on the dark energy parameters, w0 and wa. We show that Ω k and ∑m ν can be well constrained in this model; the 95% CL limits are: -0.0153<Ω k<0.0167 and ∑m ν<0.56eV. Comparing to the case in a flat universe, we find that the error in w0 is amplified by 25.51%, and the error in wa is amplified by 0.14%; comparing to the case with a zero neutrino mass, we find that the error in w0 is amplified by 12.24%, and the error in wa is amplified by 1.63%. © 2012 Elsevier B.V.

Li F.,Shenyang University of Technology | Xie H.-L.,Northeastern University China
International Journal of Automation and Computing | Year: 2010

A visual servoing tracking controller is proposed based on the sliding mode control theory in order to achieve strong robustness against parameter variations and external disturbances. A sliding plane with time delay compensation is presented by the pre-estimate of states. To reduce the chattering of the sliding mode controller, a modified exponential reaching law and hyperbolic tangent function are applied to the design of visual controller and robot joint controller. Simulation results show that the visual servoing control scheme is robust and has good tracking performance. © 2010 Institute of Automation, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg.

Wang S.Y.,University of Newcastle | Sloan S.W.,University of Newcastle | Tang C.A.,Dalian University of Technology | Zhu W.C.,Northeastern University China
Tunnelling and Underground Space Technology | Year: 2012

This paper studies the failure mechanism for a circular tunnel in transversely isotropic rock using the numerical code Realistic Failure Process Analysis (RFPA). In RFPA, an elastic damage model is used to describe the constitutive law of the meso-scale elements, and the maximum tensile strain criterion and the Mohr-Coulomb criterion are adopted as damage thresholds to determine the tensile and shear damage respectively. A series of numerical simulations of the failure process for a plane circular tunnel in rock are conducted. Based on the simulations, two major failure modes around circular tunnels in transversely isotropic rock are numerically reproduced. Whether failure is caused by sliding along the laminated layers depends on the orientation of the laminated layers, the confining pressure, and the strength ratio of the laminated layers to the intact rock. Numerical simulations of the failure modes are given for different ratios of discontinuity strength to intact rock strength, as well as different dimensionless ratios of discontinuity width. Finally, both the failure process of tunnels in up-roll foliated rock masses and down-roll foliated rock masses are investigated by RFPA. © 2012.

Pan Q.-K.,Northeastern University China | Pan Q.-K.,Liaocheng University | Sang H.-Y.,Liaocheng University | Duan J.-H.,Liaocheng University | Gao L.,Huazhong University of Science and Technology
Knowledge-Based Systems | Year: 2014

This paper presents an improved fruit fly optimization (IFFO) algorithm for solving continuous function optimization problems. In the proposed IFFO, a new control parameter is introduced to tune the search scope around its swarm location adaptively. A new solution generating method is developed to enhance accuracy and convergence rate of the algorithm. Extensive computational experiments and comparisons are carried out based on a set of 29 benchmark functions from the literature. The computational results show that the proposed IFFO not only significantly improves the basic fruit fly optimization algorithm but also performs much better than five state-of-the-art harmony search algorithms. © 2014 Elsevier B.V. All rights reserved.

Meng L.,Northeastern University China
Bio-Medical Materials and Engineering | Year: 2014

Compute Unified Device Architecture (CUDA) is a parallel computing platform and programming model invented by NVIDIA. It enables dramatic increase in computing performance via the power of the graphics processing unit (GPU). In medical image analysis, 3D image registration generally takes relatively long time, which is not feasible for clinical applications. To solve this problem, this paper proposed a high performance computational method based on CUDA, which took full advantage of GPU parallel computing under CUDA architecture combined with image multiple scale and maximum mutual information. Experiments showed that this algorithm can not only maintain the registration accuracy but also greatly increase the speed of registration process and meet the real-time requirement of clinical application. © 2014 - IOS Press and the authors. All rights reserved.

Yan L.,Northeastern University China
International Arab Journal of Information Technology | Year: 2013

Various fuzzy data models such as fuzzy relational databases, fuzzy object-oriented databases, fuzzy objectrelational databases and fuzzy XML have been proposed in the literature in order to represent and process fuzzy information in databases and XML. But little work has been done in modeling fuzzy data types. Actually in the fuzzy data models, each fuzzy value is associated with a fuzzy data type. Explicit representations of fuzzy data types are the foundation of fuzzy data processing. To fill this gap, in this paper, we propose several fuzzy data types, including fuzzy simple data types, fuzzy collection data types and fuzzy defined data types. We further investigate how to declare the fuzzy data types in the fuzzy object-oriented database model and fuzzy XML Schema. The proposed fuzzy data types can meet the requirement of modeling fuzzy data in the fuzzy databases and fuzzy XML.

Bi Z.,Indiana University - Purdue University Fort Wayne | Xu L.D.,CAS Institute of Computing Technology | Xu L.D.,Shanghai JiaoTong University | Xu L.D.,Hefei University of Technology | And 2 more authors.
IEEE Transactions on Industrial Informatics | Year: 2014

Design and operation of a manufacturing enterprise involve numerous types of decision-making at various levels and domains. A complex system has a large number of design variables and decision-making requires real-time data collected from machines, processes, and business environments. Enterprise systems (ESs) are used to support data acquisition, communication, and all decision-making activities. Therefore, information technology (IT) infrastructure for data acquisition and sharing affects the performance of an ES greatly. Our objective is to investigate the impact of emerging Internet of Things (IoT) on ESs in modern manufacturing. To achieve this objective, the evolution of manufacturing system paradigms is discussed to identify the requirements of decision support systems in dynamic and distributed environments; recent advances in IT are overviewed and associated with next-generation manufacturing paradigms; and the relation of IT infrastructure and ESs is explored to identify the technological gaps in adopting IoT as an IT infrastructure of ESs. The future research directions in this area are discussed. © 2012 IEEE.

Ma Y.,Yanshan University | Gu N.,Yanshan University | Zhang Q.,Northeastern University China
Journal of the Franklin Institute | Year: 2014

In this paper, the problem of delay-dependent non-fragile robust H∞ control for a class of discrete-time singular systems with state-delay and parameter uncertainties is investigated. Based on singular value decomposition approach, a delay-dependent sufficient condition for the H∞ control problem for a class of discrete-time singular systems is proposed by constructing generalized Lyapunov-Krasovskii function and a new difference inequality. A memoryless state feedback controller under controller gain perturbations is designed, which guarantees that, for all admissible uncertainties, the resultant closed-loop system is regular, causal, and stable with an H∞ norm bound constraint. Numerical examples in the last will show that our results have the better performance in conservativeness than some results reported in the literature. © 2014 The Franklin Institute.

In this paper, we propose a novel color image encryption method by using Color Blend (CB) and Chaos Permutation (CP) operations in the reality-preserving multiple-parameter fractional Fourier transform (RPMPFRFT) domain. The original color image is first exchanged and mixed randomly from the standard red-green-blue (RGB) color space to R′G′B′ color space by rotating the color cube with a random angle matrix. Then RPMPFRFT is employed for changing the pixel values of color image, three components of the scrambled RGB color space are converted by RPMPFRFT with three different transform pairs, respectively. Comparing to the complex output transform, the RPMPFRFT transform ensures that the output is real which can save storage space of image and convenient for transmission in practical applications. To further enhance the security of the encryption system, the output of the former steps is scrambled by juxtaposition of sections of the image in the reality-preserving multiple-parameter fractional Fourier domains and the alignment of sections is determined by two coupled chaotic logistic maps. The parameters in the Color Blend, Chaos Permutation and the RPMPFRFT transform are regarded as the key in the encryption algorithm. The proposed color image encryption can also be applied to encrypt three gray images by transforming the gray images into three RGB color components of a specially constructed color image. Numerical simulations are performed to demonstrate that the proposed algorithm is feasible, secure, sensitive to keys and robust to noise attack and data loss. © 2014 Elsevier B.V.

Zhao C.,Hong Kong University of Science and Technology | Gao F.,Hong Kong University of Science and Technology | Wang F.,Northeastern University China
Industrial and Engineering Chemistry Research | Year: 2010

Spectroscopy is a useful tool for analyzing chemical information in batch processes. However, conventional spectroscopic techniques can lead to complex model structures and difficult-to-interpret results because of the direct use of redundant wavelength variables. To solve this problem, the ICA technique has been used first to reveal the underlying independent sources from the observed mixtures and their mixing coefficients. This analysis associates the constituent species with their respective effects on the mixture spectra, which could make more sense for spectroscopy. In the following article, the use of mixing coefficients instead of redundant wavelength variables can provide a convenient modeling platform from which the phase-specific characteristics of chemical reactions are readily identified. Consequently, a phase-based joint modeling framework is formulated for process monitoring by combining different latent-variable- (LV-) based algorithms. It decomposes different types of systematic variations in spectral measurements (X) and then sets up different monitoring systems for them. Monitoring different parts of X can provide abundant process information about the status of the operation from a comprehensive viewpoint, thus benefitting process understanding and fault detection. The effectiveness of this approach is demonstrated by application to two case studies. © 2010 American Chemical Society.

Lu M.,Northeastern University China
Applied Mathematics and Information Sciences | Year: 2013

Scale-invariant feature transform (SIFT) was an algorithm in computer vision to detect and describe local features in images. Due to its excellent performance, SIFT was widely used in many applications, but the implementation of SIFT was complicated and time-consuming. To solve this problem, this paper presented a novel acceleration algorithm for SIFT implementation based on Compute Unified Device Architecture (CUDA). In the algorithm, all the steps of SIFT were specifically distributed and implemented by CPU or GPU, accroding to the step's characteristics or demandings, to make full use of computational resources. Experiments showed that compared with the traditional implementation of SIFT, this paper's acceleration algorithm can greatly increase computation speed and save implementation time. Furthermore, the acceleration ratio had linear relation with the number of SIFT keypoints. © 2013 NSP. Natural Sciences Publishing Cor.

Ma D.,Northeastern University China
Proceedings of the 30th Chinese Control Conference, CCC 2011 | Year: 2011

In this paper, we investigate the network protocol design for a class of networked switched linear control systems. The periodic switching signal can be viewed of a network protocol to guarantee the perfect transmission for networked switched control systems. Sampling and network-induced delay cause the asynchronous motions between switched subsystems and the corresponding switching controllers. We rewrite the original networked switched linear systems by sampled asynchronous switched linear systems with time-varying delay. Using the descriptor system representation method, we give a new asynchronous switching network protocol to guarantee the system is exponentially stable, which depends on the periodic switching interval, the rate of network-induced asynchronous switching, and the upper bound of time-varying delay. © 2011 Chinese Assoc of Automati.

Lin P.,University of Electronic Science and Technology of China | Lin P.,Beijing University of Posts and Telecommunications | Qin K.,University of Electronic Science and Technology of China | Zhao H.,University of Stockholm | Sun M.,Northeastern University China
Journal of the Franklin Institute | Year: 2012

This paper investigates average consensus problem in networks of continuous-time agents with delayed information and jointly-connected topologies. A lemma is derived by extending the Barbalats Lemma to piecewise continuous functions, which provides a new analysis approach for switched systems. Then based on this lemma, a sufficient condition in terms of linear matrix inequalities (LMIs) is given for average consensus of the system by employing a Lyapunov approach, where the communication structures vary over time and the corresponding graphs may not be connected. Finally, simulation results are provided to demonstrate the effectiveness of our theoretical results. © 2011 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

Li W.,Ludong University | Wei X.,Ludong University | Zhang S.,Northeastern University China
IET Control Theory and Applications | Year: 2012

In this study, the problem of decentralised output-feedback stabilisation is investigated for the first time for a class of large-scale high-order stochastic non-linear systems. By developing a decentralised high-gain homogeneous domination approach, we can completely relax the power order restriction which has been the common assumption for global stabilisation of high-order stochastic non-linear systems. It is shown that under some general conditions, the equilibrium of the closed-loop system is globally asymptotically stable (GAS) in probability when the drift and diffusion vector fields vanish at the origin. The efficiency of the output-feedback controller is demonstrated by a simulation example. © 2012 The Institution of Engineering and Technology.

Zhang X.-Q.,Liaoning University | Zhao J.,Northeastern University China
International Journal of Automation and Computing | Year: 2012

This paper investigates L 2-gain analysis and anti-windup compensation gains design for a class of discrete-time switched systems with saturating actuators and L 2 bounded disturbances by using the switched Lyapunov function approach. For a given set of anti-windup compensation gains, we firstly give a sufficient condition on tolerable disturbances under which the state trajectory starting from the origin will remain inside a bounded set for the corresponding closed-loop switched system subject to L 2 bounded disturbances. Then, the upper bound on the restricted L 2-gain is obtained over the set of tolerable disturbances. Furthermore, the antiwindup compensation gains aiming to determine the largest disturbance tolerance level and the smallest upper bound of the restricted L 2-gain are presented by solving a convex optimization problem with linear matrix inequality (LMI) constraints. A numerical example is given to illustrate the effectiveness of the proposed design method. © 2012 Institute of Automation, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg.

Ma S.-M.,Northeastern University China
Journal of Combinatorial Theory. Series A | Year: 2012

Let R(n, k) denote the number of permutations of {1, 2,...,n} with k alternating runs. In this paper we present an explicit formula for the numbers R(n, k). © 2012 Elsevier Inc.

Lu L.,Northeastern University China
Proceedings of the 30th Chinese Control Conference, CCC 2011 | Year: 2011

This paper considers the output regulation problem for a class of switched linear systems with actuator saturation. Firstly, we present the regulator equation which should be solvable in order to achieve output regulation. Secondly, we study the regulatable region, being the set of initial conditions for which output regulation can be achieved. Thirdly, we present saturated continuous feedback control law and switching strategy solving the output regulation problem. The Lyapunov-based design of the controller and switching strategy is based on convex hull of multiple quadratic Lyapunov functions. The effectiveness of the results are illustrated by means of an example. © 2011 Chinese Assoc of Automati.

Tian J.,Northeastern University China
Energy Procedia | Year: 2011

[Purpose] This paper explains the basic theory and research methods of ecological security based on the basic concept of ecological security. Qinhuangdao City is the study area, the index system of its ecological security assessment was constructed on the basis of the pressure - state - response conceptual model, and its ecological security was evaluated by comprehensive index method. The evaluation result is that the ecological security index of Qinhuangdao is 0.633, and it is in the lower bound of the relatively safer state. At present, the main ecological problems are water shortage, water pollutions, large quantity of gaseous pollutants emission from heavy industry enterprises, inadequate protection of natural reserves, and insufficient investments in environmental protection. Some targeted countermeasures for strengthening regional ecological security management are proposed as following: establishing ecological security early warning system, developing and utilizing water resources rationally to improve water utilization efficiency, strengthening the marine environmental protection to ensure the security of marine environment, reducing sulfur dioxide emission volume by improving air quality through an effective way, and implementing ecological restoration project to improve the ecological carrying capacity. The ecology of Qinhuangdao would move to a safer ecological level through these channels. © 2011 Published by Elsevier B.V. Selection and/or peer-review under responsibility of International Materials Science Society.

Shen M.,Nanjing University of Technology | Ye D.,Northeastern University China
Fuzzy Sets and Systems | Year: 2013

This paper addresses the state feedback control of nonlinear continuous-time, Markovian-jump systems. The nonlinearity is represented by Takagi-Sugeno fuzzy models and the transition probability matrix is assumed to be partly known: some elements in the matrix are known, some are unknown but with known lower and upper bounds, and some are completely unknown. By making full use of the continuous property of the transition probability matrix, new sufficient conditions for the stochastic stability of the system are obtained in terms of linear matrix inequalities. We show that the conditions given are less conservative than or at least the same as those for existing results. Moreover, using the conditions obtained, we establish a method for design of a H ∞ state feedback controller. Numerical examples illustrate the effectiveness of the proposed method. © 2012 Elsevier B.V.

Sun D.Z.,Northeastern University China
Applied Mechanics and Materials | Year: 2014

The paper adopts a method of a low speed processer and FPGA based hardware accelerator SOC units to develop the MP3 player, added with some peripheral devices. The experimental results show that the system has implemented the basic functions of the MP3 player, having its own advantage on increasing the decoding speed and reducing the system consumption. The system is convenient to redesign for more function in the future because it's designed based on FPGA. In conclusion, it has a wide application prospect. © (2014) Trans Tech Publications, Switzerland.

Chang X.-H.,Bohai University | Yang G.-H.,Northeastern University China
Fuzzy Sets and Systems | Year: 2011

This work is concerned with the observer-based H∞ control synthesis problem of discrete-time Takagi-Sugeno (T-S) fuzzy systems with external disturbances. The objective is to find a new way to design the controller and observer guaranteeing a prescribed H∞ performance of the fuzzy system. By the descriptor representation approach, two new conditions for observer-based H∞ control synthesis are proposed based on various Lyapunov function candidates, which are in the form of linear matrix inequalities (LMIs). A numerical example will be given to show the efficiency of the proposed method. © 2011 Elsevier B.V. © 2011 Elsevier B.V. All rights reserved.

Ren F.,Northeastern University China
Journal of Information and Computational Science | Year: 2012

Traditional domain ontology construction methods are usually lack of generality because they will suffer from either high resource dependence or low ontology quality. In this paper, we propose a cheap domain ontology construction method which doesn't need any high cost resources or special concept extraction technology. It takes keywords in technical papers as domain concepts. Concepts' hierarchical relations are extracted with a graph generation and conversion method. We constructed an ontology in IT domain to evaluate the proposed method. Experimental results show that proposed method has a strong adaptability and it can construct domain ontology with high quality in both concepts and hierarchical relations. Copyright © 2012 Binary Information Press.

Li S.,Northeastern University China | Dai J.,Kings College
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2010

A new kind of modularized structural theory and formation method of multi-mobility metamorphic mechanisms is presented in order to form metamorphic mechanisms systematically. Planar metamorphic mechanisms are composed on the basis of developed augmented Assur group (AAG) by applying the structural forming rules of general planar mechanisms formed by Assur group (AG). The one-mobility AAG are introduced based on class II and class III AG, the structural theory and formation methodology of planar metamorphic mechanisms are proposed based on the AAG, and the basic problems such as the mobility, the metamorphic working configuration are studied. The degenerated equivalent AG of AAG in the metamorphic process and the corresponding kinematic characteristics are investigated and discussed to provide references for the synthesis of metamorphic mechanisms. Some typical spatial metamorphic group is introduced based on the concept of AAG, and the structural formation of spatial metamorphic mechanisms is given. Examples show that both planar and spatial metamorphic mechanisms can be formed by proposed one-mobility blocks systematically as general planar mechanism composed by AG. © Journal of Mechanical Engineering.

Zhang L.,Northeastern University China
Procedia Engineering | Year: 2012

We perform molecular-dynamics calculations to study the structural transformation of an Au54Cu1 in its melting process within the framework of the embedded-atom method (EAM). The melting process of this cluster involves into three stages, firstly the Cu atom in surface of this cluster moves into inner regions accompanying with the structural transformation of the local atom packing, followed by the atoms continuously interchange their positions, and finally wholly disordered. During increasing the temperature, it is identified for the melting of this cluster from the structural changes of different regions determined by atom density profiles and pair distribution functions (PDFs). © 2012 Published by Elsevier Ltd.

Yang C.,China University of Mining and Technology | Yang C.,Northeastern University China | Sun J.,University of Michigan | Ma X.,China University of Mining and Technology
Automatica | Year: 2013

This paper considers the stabilization bound problem for singularly perturbed systems (SPSs) subject to actuator saturation. A state feedback stabilization controller design method is proposed and a basin of attraction depending on the singular perturbation parameter is constructed, which facilitates the formulation of the convex optimization problem for maximizing the basin of attraction of SPSs. Finally, examples are given to show the advantages and effectiveness of the obtained results. © 2012 Elsevier Ltd. All rights reserved.

Tang L.,Northeastern University China | Guan J.,Civil Aviation University of China | Hu G.,Baosteel
Computers and Industrial Engineering | Year: 2010

This article explores the coordinated scheduling problem between production and transportation in a steelmaking shop. Two models arising from steelmaking and refining operations are considered. The first model assumes that there is a converter at the steelmaking operation and a refining furnace at the refining operation. A transporter with capacity one is available to carry out jobs from converter to a refining furnace. The objective is to minimize the maximum completion time. For this model, we provide an algorithm with worst case ratio of two and show the computational results. The second model considers more practical situation in which jobs are processed in identical parallel converters first, and then the jobs coming from same converter are transported by a dedicated trolley with capacity one to the next operations. Two objectives are considered in the second model. One is to minimize the sum of maximum completion time, idle time penalties and waiting time penalties satisfying waiting time constraints. The other is to minimize the sum of maximum completion time, idle times penalties and hot consumption penalties related to waiting times while satisfying waiting time constraints. For the model, we develop a tabu search algorithm, provide the computational results and then give the worst case analysis. © 2009 Elsevier Ltd. All rights reserved.

Sun Y.,Shenyang Medical College | Ren Q.,Shenyang Medical College | Liu X.,Shenyang Medical College | Zhao S.,Northeastern University China | Qin Y.,Shenyang Medical College
Biosensors and Bioelectronics | Year: 2013

This study demonstrates a polyelectrolyte-free method to fabricate controllable and stable all-MWNTs films via a covalent layer-by-layer (LBL) deposition. Aminated MWNTs and carboxylated MWNTs were prepared by surface functionalization, allowing the incorporation of MWNTs into highly tunable thin films through the formation of covalent amide bonds. Fourier transform infrared spectroscopy (FTIR) analysis demonstrated the formation of covalent linkages between MWNTs layers. Scanning electron microscopy (SEM) and ultraviolet-visible spectroscopy (UV-vis) were used to characterize the assembly process. Electrochemical studies indicated that the all-MWNTs film possessed a remarkable electrocatalytic activity toward dihydronicotinamide adenine dinucleotide (NADH) at relatively low potentials, without the need for redox mediators. The film thickness and the amount of assembled MWNTs were readily adjusted by simply changing the number of cycles in the LBL assembly process, which also effectively tuned the electrocatalytic activity of the film toward NADH. The film constructed with four bilayers showed a high sensitivity of 223.8μAmM-1cm-2 and a detection limit of 1.5μM, with a fast response of less than 3s. Furthermore, the all-MWNTs film also showed good selectivity and excellent stability for the determination of NADH. © 2012 Elsevier B.V..

Liu Y.,Shenyang Ligong University | Warkentin A.,Dalhousie University | Bauer R.,Dalhousie University | Gong Y.,Northeastern University China
Precision Engineering | Year: 2013

This paper presents a comprehensive study of a computationally efficient kinematic simulation to predict workpiece surface roughness in grinding using three different abrasive grain shapes (sphere, truncated cone, and cone) and a single-point diamond dressing model having both a ductile cutting and brittle fracture component. The resulting predicted workpiece surface roughness was experimentally validated for three different workpiece speeds, three different dressing depths of cut and three different dressing overlap ratios. For the surface grinding and single-point dressing conditions used in this research, the results showed that the dressing parameters used in the simulations supersede the assumed abrasive grain shape in their ability to influence the predicted workpiece surface finish. Furthermore, the corresponding average measured and predicted workpiece surface roughness agreed within approximately 7-11%. © 2013 Elsevier Inc.

Tong S.C.,Liaoning University of Technology | Li Y.M.,Liaoning University of Technology | Zhang H.-G.,Northeastern University China
IEEE Transactions on Neural Networks | Year: 2011

In this paper, two adaptive neural network (NN) decentralized output feedback control approaches are proposed for a class of uncertain nonlinear large-scale systems with immeasurable states and unknown time delays. Using NNs to approximate the unknown nonlinear functions, an NN state observer is designed to estimate the immeasurable states. By combining the adaptive backstepping technique with decentralized control design principle, an adaptive NN decentralized output feedback control approach is developed. In order to overcome the problem of explosion of complexity inherent in the proposed control approach, the dynamic surface control (DSC) technique is introduced into the first adaptive NN decentralized control scheme, and a simplified adaptive NN decentralized output feedback DSC approach is developed. It is proved that the two proposed control approaches can guarantee that all the signals of the closed-loop system are semi-globally uniformly ultimately bounded, and the observer errors and the tracking errors converge to a small neighborhood of the origin. Simulation results are provided to show the effectiveness of the proposed approaches. © 2011 IEEE.

Ma S.-M.,Northeastern University China
Electronic Journal of Combinatorics | Year: 2013

In this paper we introduce a family of two-variable derivative polynomials for tangent and secant. Generating functions for the coefficients of this family of polyno- mials are studied. In particular, we establish a connection between these generating functions and Eulerian polynomials.

Guo Y.,Northeastern University China
Journal of Mathematical Imaging and Vision | Year: 2013

We present a novel solution for the absolute camera pose and the camera calibration (effective focal length and aspect ratio) based on perspective four point (P4P) problem. By converting perspective transformation to affine transformation and using invariance to 3D affine transformation, we explore the relationship between the dual image of the absolute conic (DIAC) and the world coordinate of camera optical center and show how the coplanar and noncoplanar cases are cast into the problems of solving a quadratic polynomial equation and an eighth degree polynomial equation in a single variable respectively using only linear algebra. In particular, geometric configurations for infinite solutions of the coplanar case are explored. We also confirm the conclusion that the upper bound of eight real solutions for noncoplanar case is attainable by an example. The performance and usefulness of our novel solution are demonstrated by thorough testing on both synthetic and real data. © Springer Science+Business Media, LLC 2012.

Li D.,Beijing Institute of Technology | Wang Y.,Beijing Institute of Technology | Xiao G.,Beijing Institute of Technology | Tang J.,Northeastern University China
Computers and Operations Research | Year: 2013

Aiming at the problem of scheduling with flexible processing routes and exceptional parts that need to visit machines located in multiple job shop cells, a pheromone based approach (PBA) using multi-agent is presented in this paper, in which various types of pheromone inspired by ant colony optimization (ACO) are adopted as the basis of negotiation among agents. By removing redundant routes and constructing coalition agents, communication cost and negotiation complexity are reduced, and more importantly, the global performance of scheduling is improved. The performance of the PBA is evaluated via experiments with respect to the mean flow time, maximum completion time, mean tardiness, ratio of tardy parts, and ratio of intercell moves. Computational results show that compared with various heuristics, the PBA has significant advantages with respect to the performance measures considered in this paper.

Zhu J.,Northeastern University China | Ma M.,Scientific Works
ACM Transactions on Speech and Language Processing | Year: 2012

This article deals with pool-based active learning with uncertainty sampling. While existing uncertainty sampling methods emphasize selection of instances near the decision boundary to increase the likelihood of selecting informative examples, our position is that this heuristic is a surrogate for selecting examples for which the current learning algorithm iteration is likely to misclassify. To more directly model this intuition, this article augments such uncertainty sampling methods and proposes a simple instability-based selective sampling approach to improving uncertainty-based active learning, in which the instability degree of each unlabeled example is estimated during the learning process. Experiments on seven evaluation datasets show that instability-based sampling methods can achieve significant improvements over the traditional uncertainty sampling method. In terms of the average percentage of actively selected examples required for the learner to achieve 99% of its performance when training on the entire dataset, instability sampling and sampling by instability and density methods achieve better effectiveness in annotation cost reduction than random sampling and traditional entropy-based uncertainty sampling. Our experimental results have also shown that instability-based methods yield no significant improvement for active learning with SVMs when a popular sigmoidal function is used to transform SVM outputs to posterior probabilities. © 2012 ACM.

Wang J.,Northeastern University China
Modern Physics Letters B | Year: 2013

Cascading failures can occur in many infrastructure networks. How to protect these networks and improve their robustness against cascading failures has been of great interest. To this end, considering that there exist some monitoring and protection measures in these networks, we propose a new mitigation strategy and investigate its effectiveness on improving the robustness level against cascading failures in Barabáasi-Albert (BA) networks and the power grid. We numerically observe that only by once adopting this strategy the robustness of BA networks and the power grid can be improved dramatically. We additionally find that BA networks and the power grid can reach the strongest robustness against cascading failures in the case of the specific value of the parameter α, which controls the strength of the initial load on a node. And we obtain the correlation between the load distribution and the effectiveness of the mitigation strategy. Our findings can well explain the origin of the stronger robustness against cascading failures of complex networks and may be very useful for guiding the improvement robustness of infrastructure networks and avoiding various cascading-failure-induced disasters in the real world. © 2013 World Scientific Publishing Company.

Ma J.,Northeastern University China | Sun Y.-S.,North China Electrical Power University | Li B.-W.,Dalian University of Technology
International Journal of Heat and Mass Transfer | Year: 2013

Spectral collocation method (SCM) has been extended to analyze one-dimensional radiative transfer problem in nonlinear anisotropic scattering medium with space-dependent scattering coefficient. Spatial and angular distributions of radiative intensity are expressed by Chebyshev polynomials and discretized by SCM. Comparisons between SCM and available data in references indicate that, SCM is accurate and efficient for radiative transfer in the one-dimensional nonlinear anisotropic and space-dependent scattering medium. When the same nodes are used by both SCM and Chebyshev collocation spectral method base on discrete ordinates method (SP-DOM), SCM is much more economical than SP-DOM. © 2013 Elsevier Ltd. All rights reserved.

Wu D.,Northeastern University China
Journal of Alloys and Compounds | Year: 2014

We have successfully doped Pt and Ga into CaFe4As3 and investigated the structure and physical properties of CaFe3.64X0.36As3 (X = Pt, Ga). Two magnetic transition temperatures remain unchanged upon Pt or Ga doping, as confirmed by specific heat, electrical resistivity and magnetic susceptibility. The electrical resistivity of CaFe4As3 is reduced by approximately half with Pt dopant but increases by an order of magnitude with Ga doping, consistent with the changes in their Hall coefficients, which indicates the effects of Pt and Ga doping give us a different modification on physical properties and electronic structure in CaFe4As3. © 2014 Elsevier B.V.

Yang H.,Nanjing University of Aeronautics and Astronautics | Jiang B.,Nanjing University of Aeronautics and Astronautics | Zhang H.,Northeastern University China
Systems and Control Letters | Year: 2012

This paper addresses the stabilization issue of a class of switched nonlinear systems where each mode may be non-minimum phase, and the states of linearized dynamics of all modes compose the whole state space. Time dependent and state dependent stabilization switching laws are provided by considering both common and multiple Lyapunov functions. The new results are applied to the aggregation problem of nonlinear multi-agent systems with designable switching connection topology. Finally, an aircraft team example illustrates the efficiency of the proposed approaches. © 2012 Elsevier B.V. All rights reserved.

Shi X.,Liaoning University of Petroleum and Chemical Technology | Shi X.,Northeastern University China | Zhao J.,Liaoning University of Petroleum and Chemical Technology | Xu X.,Liaoning University of Petroleum and Chemical Technology
Physica A: Statistical Mechanics and its Applications | Year: 2015

The mean-field theory (MFT) is used to study the dynamical response of the mixed spin-1 and spin-3/2 Ising model with Fe4N structure in the presence of a sinusoidal oscillating magnetic field. The Glauber dynamic is used to describe the time evolution of the system and the mean-field dynamic equations are given. Dynamic phase transition diagrams are presented in the T/|J| - h0/|J| plane. The dependence of the phase diagram on single-ion anisotropy strengths is also studied by the MFT. Besides second-order phase transition, lines of first-order phase transition, the dynamic tricritical point and the critical end point are found. In particular, the system exhibits first-order-order phase transitions, which cannot be found in previous studies in the mixed spin-1 and spin-3/2 Ising model using the MFT. © 2014 Elsevier B.V. All rights reserved.

Zhao Y.,Northeastern University China | Zhao Y.,University of Michigan | Zikanov O.,University of Michigan
Journal of Fluid Mechanics | Year: 2012

Abstract Flow of an electrically conducting fluid in a toroidal duct of square cross-section is analysed. The flow is driven by the azimuthal Lorentz force resulting from the interaction between the radial electric currents created by the difference of electric potential maintained between the cylinder walls and the strong magnetic field imposed in the axial direction. The flow geometry and the value of the Hartmann number correspond to the experiment of Moresco & Alboussière (J. Fluid Mech., vol. 504, 2004, pp. 167-181). The purpose of the analysis is to reveal the flow features at Reynolds numbers below the threshold of transition to turbulence in Hartmann layers. We find that the flow experiences a complex evolution. The laminar base flow experiences the first instability at the Reynolds number significantly smaller than that of the threshold. The instability is axisymmetric and oscillatory. Turbulence appears at a slightly higher Reynolds number. Right up to the Hartmann layer instability, the turbulence remains localized in a layer near the outer cylinder wall. It is demonstrated that the turbulence may affect the transition in the Hartmann layers via unsteady forcing of the outer flow. © 2012 Cambridge University Press.

Chang X.-H.,Bohai University | Yang G.-H.,Northeastern University China
Asian Journal of Control | Year: 2011

This paper addresses robust constrained model predictive control (MPC) for a class of nonlinear systems with structured time-varying uncertainties. First, the Takagi-Sugeno (T-S) fuzzy model is employed to represent a nonlinear system. Then, we develop some techniques for designing fuzzy control which guarantees the system stabilization subject to input and output constraints. Both parallel and nonparallel distributed compensation control laws (PDC and non-PDC) are considered. Sufficient conditions for the solvability of the controller design problem are given in the form of linear matrix inequalities. A simulation example is presented to illustrate the design procedures and performances of the proposed methods. © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society.

Huang X.,University of Hong Kong | Choi S.-M.,University of Hong Kong | Ching W.-K.,University of Hong Kong | Siu T.-K.,Macquarie University | Huang M.,Northeastern University China
International Journal of Production Economics | Year: 2011

A large proportion of consumer returns fall into the category of false failure returns, which refer to returns without functional defects. In this paper, we consider profits resulting from exerting costly effort to reduce false failure returns in a reverse supply chain. The supply chain as a whole has a strong incentive to reduce such returns for cost saving. However, retailers typically enjoy a full credit provided by suppliers for returns, so they may not have sufficient incentives to exert enough effort for supply chain profit maximization. In some scenarios retailers may even have the motivation to encourage such returns. We suggest using a coordination contract to resolve this profit conflict. We introduce a quantity discount contract which specifies a payment to the retailer with an amount exponentially decreasing in the number of returns. We present explicit forms of such contracts given different assumptions about the distribution of the number of returns. We also prove that the contract is Pareto improving. Besides, it is shown that when the contract is applied in a closed-loop supply chain, it can deter retailer's potential incentive to encourage returns. Moreover, some modifications of the contract can lead to easy allocation of supply chain profit. © 2011 Elsevier B.V. All right reserved.

Liang F.,Shenyang University of Chemical Technology | Wen B.,Northeastern University China
Acta Mechanica Solida Sinica | Year: 2011

Applying the multidimensional Lindstedt-Poincaré (MDLP) method, we study the forced vibrations with internal resonance of a clamped-clamped pipe conveying fluid under external periodic excitation. The frequency-amplitude response curves of the first-mode resonance with internal resonance are obtained and its characteristics are discussed; moreover, the motionsof the first two modes are also analyzed in detail. The present results reveal rich and complex dynamic behaviors caused by internal resonance and that some of the internal resonances are decided by the excitation amplitude. The MDLP method is also proved to be a simple and efficient technique to deal with nonlinear dynamics. © 2011 The Chinese Society of Theoretical and Applied Mechanics.

Wang L.,Northeastern University China
Sensors and Actuators, B: Chemical | Year: 2016

To realize the differential structure (which is an effective method to improve the sensitivity) in the humidity sensor, a novel differential humidity sensing structure, which has two kinds of sub units with opposite sensing properties, is designed. The content-based differential humidity sensing device made of conductive polymer composite is used as an example to exhibit the design method. The content-based differential humidity sensing device includes the "negative humidity coefficient unit (NHCU)" and the "positive humidity coefficient unit (PHCU)". The sensitive material in NHCU/PHCU is the composite with low/high conductive phase content, which results in "a decrease"/"an increase" of the NHCU/PHCU resistance with the increase of the humidity. Through using NHCU and PHCU as the neighboring arms of an electrical bridge, the humidity is converted to a voltage. The results show that the "sensitivity"/"hysteresis error" can be increased/decreased by using the content-based differential structure. The "non-linear error"/"response time" of the content-based differential sensor is between those of NHCU and PHCU. © 2015 Elsevier B.V. All rights reserved.

Sun P.,Northeastern University China
Electronic Journal of Combinatorics | Year: 2015

In this paper the number of standard Young tableaux (SYT) is evaluated by the methods of multiple integrals and combinatorial summations. We obtain the product formulas of the numbers of skew SYT of certain truncated shapes, including the skew SYT ((n + k)r+1,nm-1)/(n — 1)rtruncated by a rectangle or nearly a rectangle, the skew SYT of truncated shape ((n + 1)3, nm- 2)/(n — 2)\ (22), and the SYT of truncated shape ((n + 1)2, nm-2)\ (2). © 2015, International Press of Boston, Inc. All rights reserved.

Chen S.-S.,Northeastern University China | Li B.-W.,Dalian University of Technology
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2014

A collocation spectral domain decomposition method (CSDDM) based on the influence matrix technique is developed to solve radiative transfer problems within a participating medium of 2D partitioned domains. In this numerical approach, the spatial domains of interest are decomposed into rectangular sub-domains. The radiative transfer equation (RTE) in each sub-domain is angularly discretized by the discrete ordinates method (DOM) with the SRAPN quadrature scheme and then is solved by the CSDDM directly. Three test geometries that include square enclosure and two enclosures with one baffle and one centered obstruction are used to validate the accuracy of the developed method and their numerical results are compared to the data obtained by other researchers. These comparisons indicate that the CSDDM has a good accuracy for all solutions. Therefore this method can be considered as a useful approach for the solution of radiative heat transfer problems in 2D partitioned domains. © 2014 Elsevier Ltd.

Lu Z.,Northeastern University China
Yuanzineng Kexue Jishu/Atomic Energy Science and Technology | Year: 2011

The first wall structural material of fusion reactors must meet extremely rigorous operation environment requirements and it is one of the key factors restricting the development of fusion reactors. Nano-structured oxide dispersion strengthened (ODS) steels are the leading candidates for fusion first wall due to their excellent irradiation resistance coming from their characteristic microstructures. This paper described briefly the current state of development and understanding of ODS steels.

Zhang X.,Northeastern University China | Zhang X.,CAS Institute of Theoretical Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2010

The current observational data imply that the universe would end with a cosmic doomsday in the holographic dark energy model. However, unfortunately, the big-rip singularity will ruin the theoretical foundation of the holographic dark energy scenario. To rescue the holographic scenario of dark energy, we employ the braneworld cosmology and incorporate the extra-dimension effects into the holographic theory of dark energy. We find that such a mend could erase the big-rip singularity and leads to a de Sitter finale for the holographic cosmos. Therefore, in the holographic dark energy model, the extra-dimension recipe could heal the world. © 2009 Elsevier B.V. All rights reserved.