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Beijing, China

The Beijing University of Posts and Telecommunications is a key national university distinguished by the teaching and research in the field of cable communications, wireless communications, computer, and electronic engineering. BUPT comprises 17 schools, and has an international school program with Queen Mary, University of London.The university was created in 1955 under the Ministry of Posts and Telecommunications and the Communications Department of the General Staff Department of the People's Liberation Army. The name was changed from Institute to University in 1993. It is the most famous and renowned university in the field of telecommunications in China. Wikipedia.

Liu A.,Zhejiang Sci-Tech University | Liu A.,Zhejiang University | Xu T.,Zhejiang Sci-Tech University | Ren Q.,Zhejiang Sci-Tech University | And 3 more authors.
Electrochemistry Communications | Year: 2012

A close-packed 2D assembly of plasmonic gold nanostructure was fabricated on a diamond-like carbon film by a two-step electrodeposition via reduced graphene oxide (rGO) modulation. The oxygen functionalities at the rGO surface which were controlled by changing electrochemical reduction time of GO provided reactive sites for nucleation and growth of gold nanoparticles. The Raman intensity of rhodamine B obtained from the gold assembly showed an 860-fold increase compared with that from Si reference, indicating a coupling of localized electromagnetic field enhancement and chemical enhancement. Our research offered a novel way for metallic plasmonic fabrication to realize their potential applications in biochemical analysis, environmental monitoring, disease detection and food safety. © 2012 Elsevier B.V.

Li J.B.,Beijing University of Posts and Telecommunications
Advanced Materials Research | Year: 2014

With the Internet of Vehicles popular, many service providers can provide vehicle service (e.g. Web service, Application, Network access, etc.) for users. Then more and more vehicle services are published in Internet of Vehicles, and how to measure the quality of vehicle service (QoVS) become a very important issue. In this paper, we propose a QoVS prediction approach using eAutoregressive integrated moving average. Our approach can predict the QoVS of different vehicle services according their history data. In order to evaluate our proposed approach, we construct experiments and results show that our approach is very effective in internet of vehicles. © (2014) Trans Tech Publications, Switzerland.

Liu R.H.,Beijing University of Posts and Telecommunications
Applied Mechanics and Materials | Year: 2014

Aiming at the difference between satellite’s signal frequency spectrum and satellite signals under specific channel condition, larger fluctuation and ineffective threshold searching method by adopting traditional energy, the paper improved singular point’s performance detection of traditional wavelet transform, selected suitable searching threshold by ultimately combining with both advantages and promoted searching performance of satellite signals under specific channel condition. Based on preprocessed order-1 subspace tracing algorithm of space sign function and infinite norm normalization, the paper solved the problem of degenerating performance of regular order-1 subspace tracing algorithm under noise environment of a stationary distribution effectively. © (2014) Trans Tech Publications, Switzerland.

Wang Z.,CAS Institute of Electronics | Yang D.,Beijing University of Posts and Telecommunications | Milstein L.B.,University of California at San Diego
IEEE Transactions on Communications | Year: 2012

This paper addresses an adaptive multi-user resource allocation for a distributed multi-carrier direct sequencecode division multiple access (MC DS-CDMA) network. The packet throughput, which turns out to be nonconvex and nondifferentiable, is considered to measure the system performance. A sub-optimal non-cooperative power control game is proposed to adaptively allocate the transmit power, available subchannels and alphabet size by minimizing the transmit power with a transmit power constraint and a packet throughput requirement. Also, the paper investigates the effect of channel estimation error on the adaptive resource allocation in a distributed MC DS-CDMA network, and shows that using the Gaussian approximation for the signal-dependent noise can lead to a nontrivial discrepancy in system performance. © 2012 IEEE.

Han J.-T.,Beijing University of Posts and Telecommunications
Environment, Energy and Sustainable Development - Proceedings of the 2013 International Conference on Frontier of Energy and Environment Engineering, ICFEEE 2013 | Year: 2014

Online shopping is becoming to be more and more as the express industry has developed rapidly. But the alliance that price is agreed by several courier firms appears sometimes as the price competition occurs. This paper discusses the problem of the price completion of the service homogeneity provided by courier service online market under the condition of complete information. The courier pricing competition game among several market agents is designed based on Bertrand model. It is proved that the price alliance is unstable. Some rationalization proposals are presented. © 2014 Taylor & Francis Group, London.

Chang Z.,Zhengzhou University | Wen Q.,Beijing University of Posts and Telecommunications
Chinese Journal of Electronics | Year: 2011

New properties and methods about the linear complexity and the k-error linear complexity of binary 2n-periodic sequences are provided. Using Games-Chan algorithm and new method, we give some new results about k-error linear complexity, and the method to count the number of critical error sequences is also provided.

Ding Z.,Newcastle University | Peng M.,Beijing University of Posts and Telecommunications | Chen H.-H.,National Cheng Kung University
IEEE Transactions on Communications | Year: 2012

In this paper, we consider a secrecy relaying communication scenario where all nodes are equipped with multiple antennas. An eavesdropper has the access to the global channel state information (CSI), and all the other nodes only know the CSI not associated with the eavesdropper. A new secrecy transmission protocol is proposed, where the concept of interference alignment is combined with cooperative jamming to ensure that artificial noise from transmitters can be aligned at the destination, but not at the eavesdropper due to the randomness of wireless channels. Analytical results, such as ergodic secrecy rate and outage probability, are developed, from which more insightful understanding of the proposed protocol, such as multiplexing and diversity gains, can be obtained. A few special cases, where outage probability cannot be decreased to zero regardless of SNR, are also discussed. Simulation results are provided to demonstrate the performance of the proposed secrecy transmission protocol. © 2012 IEEE.

Liao Q.-Z.,Beijing University of Posts and Telecommunications
Beijing Gongye Daxue Xuebao/Journal of Beijing University of Technology | Year: 2015

Like dual quaternion, double quaternion can be used in mathematic modeling of spatial mechanisms. The advantages of fast computing and robustness can be used in some special applications. So far, international journals have published some papers introducing this method, however, these methods need special mathematic knowledge and are not easy to understand. Based on the matrix method, the homogeneous transformation matrix can be divided into rotation and translation parts, and then the two parts are transformed into Hamilton operator. Double quaternion is then derived. By using the double quaternion, a small error will be introduced into the results, however, it can be controlled by the program. Another advantage is that it needs less multiply computing. A numerical example is given to verify the method, and this method can be easily understood. © 2015, Beijing University of Technology. All right reserved.

Ding S.,China University of Mining and Technology | Ding S.,Beijing University of Posts and Telecommunications | Qi B.,China University of Mining and Technology
Artificial Intelligence Review | Year: 2012

Granular support vector machine (GSVM) is a new learning model based on Granular Computing and Statistical Learning Theory. Compared with the traditional SVM, GSVM improves the generalization ability and learning efficiency to a large extent. This paper mainly reviews the research progress of GSVM. Firstly, it analyzes the basic theory and the algorithm thought of GSVM, then tracking describes the research progress of GSVM including the learning model and specific applications in recent years, finally points out the research and development prospects. © 2011 Springer Science+Business Media B.V.

Huang J.,Beijing University of Posts and Telecommunications | Liu Y.,Chongqing University of Posts and Telecommunications
Expert Systems with Applications | Year: 2010

Multicast routing is regarded as a critical component in networks especially the real-time applications become increasingly popular in recent years. This paper proposes a novel fast multi-objective evolutionary algorithm called MOEAQ for solving multicast routing problem (MRP) in MANET. The strengths and limitations of the well-known multicast model are analyzed firstly in this work. Specifically, the "Greedy" and "family competition" approach are integrated into MOEAQ to speed up the convergence and to maintain the diversity of population. The theoretical validations for the proposed method are presented to show its efficiency. After that, a CBT-based improved protocol is then proposed to simplify the MRP, and finally, the performance of MANET scaled from 20 to 200 nodes with different types of service is evaluated by OPNET, experimental results show that the proposed method is capable of achieving faster convergence and more preferable for multicast routing in MANET compared with other GA-based protocol well-known in the literature. © 2009.

Zuo X.,Beijing University of Posts and Telecommunications | Zhang G.,CAS Institute of Microelectronics | Tan W.,IBM
IEEE Transactions on Automation Science and Engineering | Year: 2014

Public clouds provide Infrastructure as a Service (IaaS) to users who do not own sufficient compute resources. IaaS achieves the economy of scale by multiplexing, and therefore faces the challenge of scheduling tasks to meet the peak demand while preserving Quality-of-Service (QoS). Previous studies proposed proactive machine purchasing or cloud federation to resolve this problem. However, the former is not economic and the latter for now is hardly feasible in practice. In this paper, we propose a resource allocation framework in which an IaaS provider can outsource its tasks to External Clouds (ECs) when its own resources are not sufficient to meet the demand. This architecture does not require any formal inter-cloud agreement that is necessary for the cloud federation. The key issue is how to allocate users' tasks to maximize the profit of IaaS provider while guaranteeing QoS. This problem is formulated as an integer programming (IP) model, and solved by a self-adaptive learning particle swarm optimization (SLPSO)-based scheduling approach. In SLPSO, four updating strategies are used to adaptively update the velocity of each particle to ensure its diversity and robustness. Experiments show that, SLPSO can improve a cloud provider's profit by 0.25%-11.56% compared with standard PSO; and by 2.37%-16.71% for problems of nontrivial size compared with CPLEX under reasonable computation time. © 2004-2012 IEEE.

Wang Y.,Nanjing University of Posts and Telecommunications | Wang Y.,Japan National Institute of Information and Communications Technology | Wang Y.,Beijing University of Posts and Telecommunications | Nakao A.,University of Tokyo
IEEE Transactions on Systems, Man, and Cybernetics, Part B: Cybernetics | Year: 2010

In overlay networks, the interplay between network structure and dynamics remains largely unexplored. In this paper, we study dynamic coevolution between individual rational strategies (cooperative or defect) and the overlay network structure, that is, the interaction between peer's local rational behaviors and the emergence of the whole network structure. We propose an evolutionary game theory (EGT)-based overlay topology evolution scheme to drive a given overlay into the small-world structure (high global network efficiency and average clustering coefficient). Our contributions are the following threefold: From the viewpoint of peers' local interactions, we explicitly consider the peer's rational behavior and introduce a link-formation game to characterize the social dilemma of forming links in an overlay network. Furthermore, in the evolutionary link-formation phase, we adopt a simple economic process: Each peer keeps one link to a cooperative neighbor in its neighborhood, which can slightly speed up the convergence of cooperation and increase network efficiency; from the viewpoint of the whole network structure, our simulation results show that the EGT-based scheme can drive an arbitrary overlay network into a fully cooperative and efficient small-world structure. Moreover, we compare our scheme with a search-based economic model of network formation and illustrate that our scheme can achieve the experimental and analytical results in the latter model. In addition, we also graphically illustrate the final overlay network structure; finally, based on the group selection model and evolutionary set theory, we theoretically obtain the approximate threshold of cost and draw the conclusion that the small value of the average degree and the large number of the total peers in an overlay network facilitate the evolution of cooperation. © 2006 IEEE.

Zhong Y.-X.,Beijing University of Posts and Telecommunications
Beijing Youdian Daxue Xuebao/Journal of Beijing University of Posts and Telecommunications | Year: 2010

A completely new approach to artificial intelligence, named mechanism approach, was presented in the paper to cope with the advanced intelligence (AI) research. It was discovered that the core mechanism of intelligence formation is a series of conversions-the one from information to knowledge and the one from knowledge to intelligence (intelligent strategy), or more concisely information-knowledge-intelligence transform. It was also discovered that there is a system of knowledge ecology from experimental knowledge to regular knowledge and further to commonsense knowledge. To combine the mechanism approach and the ecology system of knowledge, it is discovered that the three existed schools of advanced intelligence theory (the structuralism, functionalism, and behaviorism) are unified within the framework of the mechanism approach. More interestingly, it can also be proved that the general form of mechanism approach is the information conversion which is an effective approach to advanced intelligence and as significant as that of material conversion and energy conversion in physics.

Liao Q.-Z.,Beijing University of Posts and Telecommunications
Beijing Youdian Daxue Xuebao/Journal of Beijing University of Posts and Telecommunications | Year: 2010

The problem discussed here is the research work of linkage mechanisms, which has relations with geometry. These works include planar and spatial mechanisms, series and parallel mechanisms, geometrical modeling of the mechanisms and equations solving. The kinematic analysis and synthesis of mechanisms are also discussed. Except traditional method, modern ones for solving these problems are outlined here. When computer is used, some special problems appear in the calculation and are also discussed.

Abdulla A.E.A.A.,Tohoku University | Nishiyama H.,Tohoku University | Yang J.,Beijing University of Posts and Telecommunications | Ansari N.,New Jersey Institute of Technology | Kato N.,Tohoku University
IEEE Transactions on Wireless Communications | Year: 2012

colorblack{Power-aware routing in Wireless Sensor Networks (WSNs) is designed to adequately prolong the lifetime of severely resource-constrained ad hoc wireless sensor nodes}. Recent research has identified the energy hole problem in single sink-based WSNs, a characteristic of the many-to-one (convergecast) traffic patterns. In this paper, we propose HYbrid Multi-hop routiNg (HYMN) algorithm, which is a hybrid of the two contemporary multi-hop routing algorithm architectures, namely, flat multi-hop routing that utilizes efficient transmission distances, and hierarchical multi-hop routing algorithms that capitalizes on data aggregation. We provide rigorous mathematical analysis for HYMNoptimize it and model its power consumption. In addition, through extensive simulations, we demonstrate the effective performance of HYMN in terms of superior connectivity. © 2012 IEEE.

Wang Y.,Beijing University of Posts and Telecommunications | Nakao A.,University of Tokyo | Vasilakos A.V.,University of Western Macedonia
ACM Transactions on Autonomous and Adaptive Systems | Year: 2012

Currently, on one hand, there exist much work about network formation and/or growth models, and on the other hand, cooperative strategy evolutions are extensively investigated in biological, economic, and social systems. Generally, overlay networks are heterogeneous, dynamic, and distributed environments managed by multiple administrative authorities, shared by users with different and competing interests, or even autonomously provided by independent and rational users. Thus, the structure of a whole overlay network and the peers' rational strategies are ever coevolving. However, there are very few approaches that theoretically investigate the coevolution between network structure and individual rational behaviors. The main motivation of our article lies in that: Unlike existing work which empirically illustrates the interaction between rational strategies and network structure (through simulations), based on EGT (Evolutionary Game Theory), we not only infer a condition that could favor the cooperative strategy over defect strategy, but also theoretically characterizes the structural properties of the formed network. Specifically, our contributions are twofold. First, we strictly derive the critical benefit-to-cost ratio (b/c) that would facilitate the evolution of cooperation. The critical ratio depends on the network structure (the number of peers in system and the average degree of each peer), and the evolutionary rule (the strategy and linking mutation probabilities). Then, according to the evolutionary rules, we formally derive the structural properties of the formed network in full cooperative state. Especially, the degree distribution is compatible with the power-law, and the exponent is (4-3v)/(1-3v), where v is peer's linking mutation probability. Furthermore, we show that, without being harmful to cooperation evolution, a slight change of the evolutionary rule will evolve the network into a small-world structure (high global efficiency and average clustering coefficient), with the same power-law degree distribution as in the original evolution model. © 2012 ACM.

Yu Y.,Beijing University of Posts and Telecommunications | Zheng X.,Henan University
Signal Processing | Year: 2011

Orthogonal frequency division multiplexing (OFDM) is sensitive to carrier frequency offset (CFO) that causes inter-carrier interference (ICI). In this paper, a particle filter (PF) method augmented with ant colony optimization (ACO) is developed to estimate the CFO. The ACO for continuous domains is incorporated into PF to optimize the sampling process. Unlike the standard PF, resampling is not required in the method. Moreover, it does not require the noise distribution. Simulation results show that the proposed method is effective when estimating the CFO and can effectively combat the effect of ICI in OFDM systems. © 2010 Elsevier B.V. All rights reserved.

Ming Y.,Beijing University of Posts and Telecommunications
Neurocomputing | Year: 2015

The times of Big Data promotes increasingly higher demands for fine-motion analysis, such as hand activity recognition. However, in real-world scenarios, hand activity recognition suffers huge challenges with variations of illumination, poses and occlusions. The depth acquisition provides an effective way to solve the above issues. In this paper, a complete framework of hand activity recognition combined depth information is presented for fine-motion analysis. First, the improved graph cuts method is introduced to hand location and tracking over time. Then, combined with 3D geometric characteristics and hand behavior prior information, 3D Mesh MoSIFT feature descriptor is proposed to represent the discriminant property of hand activity. Simulation orthogonal matching pursuit (SOMP) is used to encode the visual codewords. Experiments are based on the public available depth datasets (ChaLearn gesture dataset and our captured RGB-D dataset). Compared with the previous popular approaches, our framework has a consistently better performance for real-world applications with fine-motion analysis in terms of effectiveness, robustness and universality. © 2014 Elsevier B.V.

Wang X.-Y.,Liaoning Normal University | Wang X.-Y.,Beijing University of Posts and Telecommunications | Bu J.,Liaoning Normal University
Digital Signal Processing: A Review Journal | Year: 2010

Automated segmentation of images has been considered an important intermediate processing task to extract semantic meaning from pixels. In general, the fuzzy c-means approach (FCM) is highly effective for image segmentation. But for the conventional FCM image segmentation algorithm, cluster assignment is based solely on the distribution of pixel attributes in the feature space, and the spatial distribution of pixels in an image is not taken into consideration. In this paper, we present a novel FCM image segmentation scheme by utilizing local contextual information and the high inter-pixel correlation inherent. Firstly, a local spatial similarity measure model is established, and the initial clustering center and initial membership are determined adaptively based on local spatial similarity measure model. Secondly, the fuzzy membership function is modified according to the high inter-pixel correlation inherent. Finally, the image is segmented by using the modified FCM algorithm. Experimental results showed the proposed method achieves competitive segmentation results compared to other FCM-based methods, and is in general faster. © 2009 Elsevier Inc. All rights reserved.

Lin P.,Chongqing University | Lin P.,Beijing University of Posts and Telecommunications | Dai M.,Chongqing University | Song Y.,Chongqing University
Journal of the Franklin Institute | Year: 2014

This paper is concerned with a consensus problem of a class of second-order multi-agent systems with nonuniform time-delays. A distributed consensus algorithm is adopted to drive all agents to reach consensus and move together with a constant velocity. By a frequency domain approach, an upper bound on the maximum of the time-delays that can be tolerated is given for the consensus of the system. © 2013 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

Zhang M.,Beijing University of Posts and Telecommunications
2014 23rd Wireless and Optical Communication Conference, WOCC 2014 | Year: 2014

We demonstrate a proposed LED driver with a 2nd order pre-emphasis circuit for visible light communications with a E/O/E bandwidth of 130 MHz, and with a flatness of 0.4 dB up to 110MHz. Experiments show that the bit error rate of the system at 300 Mbps is below 1×10-10 in a 231-1 NRZ OOK PRBS transmission. © 2014 IEEE.

Wu X.,Beijing University of Posts and Telecommunications
Proceedings of 2013 3rd International Conference on Computer Science and Network Technology, ICCSNT 2013 | Year: 2014

Recently, mashup is becoming increasingly popular. They are used in a great many fields. Mashup is an aggregated application which consists of two or more resources. When several alternative mashup resources are available, how to select appropriate resources according to user's preferences is the focus of this paper. In this paper, we apply the TO PS IS (Technique for Order Preference by Similarity to an Ideal Solution) method to select the mashup resource. Using this method, the user can achieve the maximum satisfaction for the mashup application. This method excellently solves the selection problem of mashup resource according to user's preferences. The premise of resource selection is that all these resources can be combined into mashup, i.e., they can be the components of mashup. These resources have the same or similar functions but possess different non-functions. In this paper, mashup resource selection based on user's preference means to select the satisfactory resource for the user according to their needs. © 2013 IEEE.

Minga Y.,Beijing University of Posts and Telecommunications | Hong X.,University of Oulu
Neurocomputing | Year: 2016

In this paper, we design a unified 3D face authentication system for practical use. First, we propose afacial depth recovery method to construct a facial depth map from stereoscopic videos. It effectivelyutilize prior facial information and incorporate the visibility term to classify static and dynamic pixels forrobust depth estimation. Secondly, in order to make 3D face authentication more accurate and consistent,we present an intrinsic scale feature detection for interesting points on 3D facial mesh regions.Then, a novel feature descriptor is proposed, called Local Mesh Scale-Invariant Feature Transform(LMSIFT) to reflect the different face recognition abilities in different facial regions. Finally, the sparseoptimization problem of visual codebook is used to 3D face learning. We evaluate our approach onpublicly available 3D face databases and self-collected realistic scene databases. We also develop aninteractive education system to investigate its performance in practice, which demonstrates the highperformance of the proposed approach for accurate 3D face authentication. Compared with previouspopular approaches, our system has consistently better performance in terms of effectiveness, robustnessand universality. © 2015 Elsevier B.V..

Chang Z.-L.,Zhengzhou University | Li D.-D.,Beijing University of Posts and Telecommunications
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences | Year: 2014

In this paper, one new class of quaternary generalized cyclotomic sequences with the period 2pq over F4 is established. The linear complexity of proposed sequences with the period 2pq is determined. The results show that such sequences have high linear complexity. Copyright © 2014 The Institute of Electronics, Information and Communication Engineers.

Luan G.,Beijing University of Posts and Telecommunications
IEEE Communications Letters | Year: 2014

This letter investigates buffer behavior in data center networks (DCNs). An analytical framework to model a switch buffer in a DCN is proposed. Based on a martingale perspective, we derive the expectation of the stopping time, and we provide explicit expression for the relationship between overflow probability of the stopping time and buffer size. Simulations are given to validate the analysis. In addition, an example is provided to explain how the method can be applied to switch design. © 2014 IEEE.

Wang Y.,Beijing University of Posts and Telecommunications
Proceedings - 2014 9th International Conference on P2P, Parallel, Grid, Cloud and Internet Computing, 3PGCIC 2014 | Year: 2014

Botnets have started using Information obfuscation techniques include encryption to evade detection. In order to detect encrypted botnet traffic, in this paper we see detection of encrypted botnet traffic from normal network traffic as traffic classification problem. After analyses features of encrypted botnet traffic, we propose a novel meta-level classification algorithm based on content features and flow features of traffic. The content features consist of information entropy and byte frequency distribution, and the flow features consist of port number, payload length and protocol type of application layer. Then we use Naive Bayes classification algorithms to detect botnet traffic. The related experiment shows that our method has good detection effect. © 2014 IEEE.

Xinchao Z.,Beijing University of Posts and Telecommunications
Applied Soft Computing Journal | Year: 2010

The canonical particle swarm optimization (PSO) has its own disadvantages, such as the high speed of convergence which often implies a rapid loss of diversity during the optimization process, which inevitably leads to undesirable premature convergence. In order to overcome the disadvantage of PSO, a perturbed particle swarm algorithm (pPSA) is presented based on the new particle updating strategy which is based upon the concept of perturbed global best to deal with the problem of premature convergence and diversity maintenance within the swarm. A linear model and a random model together with the initial max-min model are provided to understand and analyze the uncertainty of perturbed particle updating strategy. pPSA is validated using 12 standard test functions. The preliminary results indicate that pPSO performs much better than PSO both in quality of solutions and robustness and comparable with GCPSO. The experiments confirm us that the perturbed particle updating strategy is an encouraging strategy for stochastic heuristic algorithms and the max-min model is a promising model on the concept of possibility measure. © 2009 Elsevier B.V. All rights reserved.

Ai X.,Beijing University of Posts and Telecommunications
Entropy | Year: 2014

Topological measures are crucial to describe, classify and understand complex networks. Lots of measures are proposed to characterize specific features of specific networks, but the relationships among these measures remain unclear. Taking into account that pulling networks from different domains together for statistical analysis might provide incorrect conclusions, we conduct our investigation with data observed from the same network in the form of simultaneously measured time series. We synthesize a transfer entropy-based framework to quantify the relationships among topological measures, and then to provide a holistic scenario of these measures by inferring a drive-response network. Techniques from Symbolic Transfer Entropy, Effective Transfer Entropy, and Partial Transfer Entropy are synthesized to deal with challenges such as time series being nonstationary, finite sample effects and indirect effects. We resort to kernel density estimation to assess significance of the results based on surrogate data. The framework is applied to study 20 measures across 2779 records in the Technology Exchange Network, and the results are consistent with some existing knowledge. With the drive-response network, we evaluate the influence of each measure by calculating its strength, and cluster them into three classes, i.e., driving measures, responding measures and standalone measures, according to the network communities. © 2014 by the authors.

Zhang B.,Beijing University of Posts and Telecommunications | Chen Y.,University of Maryland University College | Liu K.J.R.,University of Maryland University College
IEEE Transactions on Wireless Communications | Year: 2012

Cooperation is a promising approach to simultaneously achieve efficient utilization of spectrum resource and improve the quality of service of primary users in dynamic spectrum access networks. However, due to the selfish nature, secondary users may not act as cooperatively as primary users have expected. Therefore, how to stimulate the secondary users to play cooperatively is an important issue. In this paper, we propose a reputation-based spectrum access framework, where the cooperation stimulation problem is modeled as an indirect reciprocity game. In the proposed game, secondary users choose how to help primary users relay information and gain reputations, based on which they can access a certain amount of vacant licensed channels in the future. By formulating a secondary user's decision making as a Markov decision process, we obtain the optimal action rule, according to which the secondary user will use maximal power to help primary user relay data if the channel is not in an outage, and thus greatly improve the primary user's quality of service as well as the spectrum utilization efficiency. Moreover, we prove the uniqueness of stationary reputation distribution and theoretically derive the condition under which the optimal action rule is evolutionarily stable. Finally, simulation results are shown to verify the effectiveness of the proposed scheme. © 2002-2012 IEEE.

Qin Y.,University of Waterloo | Li W.,Beijing University of Posts and Telecommunications
Computational Statistics and Data Analysis | Year: 2016

Large covariance matrices play a fundamental role in various high-dimensional statistics. Investigating the limiting behavior of the eigenvalues can reveal informative structures of large covariance matrices, which is particularly important in high-dimensional principal component analysis and covariance matrix estimation. In this paper, we propose a framework to test the number of distinct population eigenvalues for large covariance matrices, i.e. the order of a Population Spectral Distribution. The limiting distribution of our test statistic for a Population Spectral Distribution of order 2 is developed along with its (N,p) consistency, which is clearly demonstrated in our simulation study. We also apply our test to two classical microarray datasets. © 2015 Elsevier B.V.

Wu K.,Beijing University of Posts and Telecommunications | Li C.,PLA Air Force Aviation University
Journal of Convergence Information Technology | Year: 2012

In order to solve the problems of system access authorization in trusted network, in view of the fuzziness of network environment, the randomness of user behavior and the subjectivity of historical experience, a secure authorization scheme based on the cloud model called CTAS is proposed. CTAS synthetically analyzes multiple trust characteristics and security threats of access in trusted network. The weights analysis method is used to extract the Security Degree of access. The cloud model is utilized to quantitatively construct the trusted benchmark cloud. The Security Level of access is qualitatively judged according to the Certainty Degree of the Security Degree attaching to the benchmark cloud. The access is authorized by the Security Level. Under the improved framework of Trusted Network Connect (TNC), the trust timeliness mechanism is presented to implement the reassessment of the Security Level for dynamically updating authorization. The experiments show that CTAS can timely and accurately accomplish system access authorization in TNC, effectively prevent and control security risks and threats, and provide better security, integrity and availability.

Yan J.-Y.,Beijing University of Posts and Telecommunications
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

The interaction of one-dimensional excitons and plasmons is theoretically investigated in semiconductor-insulator-metal nanowires. With the exact potentials presented analytically, the excitonic equation of motion in electron-hole-pair representation in real space is established. The optical properties of the system are derived by numerically calculating the evolution of the excitonic wave function. Linear absorption spectra demonstrate strong exciton-plasmon coupling in the nanostructures. The redshifts of the exciton absorption are found to be a result of interaction between the self-image potential and the indirect Coulomb interaction, of which the former brings the blueshift and the latter gives the redshift. The shifts reach the scale of 10 meV, which can be easily observed in experiment. Moreover, how the exciton-plasmon interaction is controlled by the parameters of the structure is also illustrated. © 2012 American Physical Society.

Huang J.-F.,Beijing University of Posts and Telecommunications
Proceedings - 2nd IEEE International Conference on Mobile Cloud Computing, Services, and Engineering, MobileCloud 2014 | Year: 2014

Android fragmentation remains a compatibility issue for third-party Android application (app) developers. Most of development teams may not have enough mobile devices for compatibility testing because of limited budget. They may not have enough time to finish the testing on tens kind of devices one by one even devices are sufficient, since the applications have to be launched on time under market pressure. In this paper, we present Mobile App Automated Compatibility Testing Service (AppACTS), which is aimed at helping developers to improve mobile application compatibility testing efficiency, save cost and ensure mobile application quality and reliability. Developers could upload their apps through a web interface, designate interesting mobile device models, and review testing report after finishing testing. The whole compatibility testing process of AppACTS includes the installation, startup, random key and screen actions, and removal of mobile apps. The architecture of AppACTS is scalable and the mobile devices of AppACTS are real devices and geographically distributed. © 2014 IEEE.

Liu G.,Wenzhou University | Wu Y.,Beijing University of Posts and Telecommunications
Progress in Electromagnetics Research | Year: 2013

This paper presents a novel design approach to design inline microstrip bandstop filter with accurate design theory and sharp skirt selectivity. This kind of bandstop filter is based on a simple coupled-line structure, indicating compact and flexible circuit layout for microstrip implementation. For a single-section bandstop filter, the scattering parameters and their constrain conditions are achieved, which provides an effective design guide for multi-section bandstop filters. Theoretical analysis indicates that the even-mode and odd-mode characteristic impedances can be easily used to determine the desired bandstop performance while the total circuit layout keeps very compact. For demonstration, seven numerical examples are designed, calculated, and compared. Finally, both experimental and simulation results of a two-section two-cell microstrip bandstop filter operating at I GHz are presented to verify the theoretical predications.

Ma Z.,Beijing University of Posts and Telecommunications | Leijon A.,KTH Royal Institute of Technology | Kleijn W.B.,Victoria University of Wellington
IEEE Transactions on Audio, Speech and Language Processing | Year: 2013

Quantization of the linear predictive coding parameters is an important part in speech coding. Probability density function (PDF)-optimized vector quantization (VQ) has been previously shown to be more efficient than VQ based only on training data. For data with bounded support, some well-defined bounded-support distributions (e.g., the Dirichlet distribution) have been proven to outperform the conventional Gaussian mixture model (GMM), with the same number of free parameters required to describe the model. When exploiting both the boundary and the order properties of the line spectral frequency (LSF) parameters, the distribution of LSF differences (\Delta{\hbox {LSF}}) can be modelled with a Dirichlet mixture model (DMM). We propose a corresponding DMM based VQ. The elements in a Dirichlet vector variable are highly mutually correlated. Motivated by the Dirichlet vector variable's neutrality property, a practical non-linear transformation scheme for the Dirichlet vector variable can be obtained. Similar to the Karhunen-Loève transform for Gaussian variables, this non-linear transformation decomposes the Dirichlet vector variable into a set of independent beta-distributed variables. Using high rate quantization theory and by the entropy constraint, the optimal inter- and intra-component bit allocation strategies are proposed. In the implementation of scalar quantizers, we use the constrained-resolution coding to approximate the derived constrained-entropy coding. A practical coding scheme for DVQ is designed for the purpose of reducing the quantization error accumulation. The theoretical and practical quantization performance of DVQ is evaluated. Compared to the state-of-the-art GMM-based VQ and recently proposed beta mixture model (BMM) based VQ, DVQ performs better, with even fewer free parameters and lower computational cost. © 2013 IEEE.

Quan Q.,Beijing University of Posts and Telecommunications
IEEJ Transactions on Electrical and Electronic Engineering | Year: 2014

A closed-form expression for the position dilution of precision (PDOP) in absolute-range-based two-dimensional (2-D) wireless location systems is derived. Then, using the closed-form expression, the observation space (OS) required for achieving the lowest PDOP of 2/√N is studied, where N is the number of measuring points. The OS is measured by central angle of a sector which covers all measuring points. The target is located at the vertex of the sector. It is shown that, for achieving the lowest PDOP of 2/√N, the OS is required to be larger than or equal to π/2 while N is even. When N = 3, the OS is instead required to be larger than or equal to 2π/3. It is also shown that the OS of 2π/3 is sufficient to achieve the lowest PDOP of 2/√N while N is odd. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. Copyright © 2013 Institute of Electrical Engineers of Japan.

Guo Y.,Beijing University of Posts and Telecommunications | Joshi J.B.D.,University of Pittsburgh
HT'10 - Proceedings of the 21st ACM Conference on Hypertext and Hypermedia | Year: 2010

Collaborative tagging has become a very popular way to share, annotate, and discover online resources in Web 2.0. Yet as the number of resources in Collaborative tagging system grows over time, sifting through the large amounts of resources and finding the right resources to recommend to the right user is becoming a challenging problem. In this paper, we investigate a probabilistic generative model for collaborative tagging, explore the implicit semantic connections in the sparse and noisy information space of heterogeneous users and unsupervised tagging. First, a modified Latent Dirichlet Allocation (LDA) model is used to cluster the tags and users simultaneously. The generalization of resource description and user could alleviate the tag noise and data sparseness of recommendation effectively. And then, considering that topic-based recommendation only takes the users' global interest into consideration without the capability of distinguishing users' interest in detail, we combine the global interests with the individual interest and community interest. Experimental results demonstrate the topicbased personalized recommendation method, which integrate both the commonality factor among users and the specialties of individuals, could alleviate data sparsity and provide a more flexible and effective recommendation than previous methods. Copyright 2010 ACM.

Wang W.,Beijing University of Posts and Telecommunications | Wang W.,Zhejiang University | Wang W.,University of Michigan | Yu G.,Zhejiang University | And 3 more authors.
IEEE Communications Magazine | Year: 2013

Adopting small cells, including femtocells, is a promising evolution of future wireless cellular systems to meet the explosive demand for high data rates. As the number of distributively deployed femtocell access points increases rapidly, interference coordination becomes the primary challenge in such heterogeneous networks. In this article, we apply several cognitive radio inspired approaches to enhance the interference coordination for femtocell networks. First, we apply spectrum sensing and statistical analysis to estimate the cross-tier interference between macrocells and femtocells. Based on this, interference coordination is investigated considering two kinds of spectrum sharing approaches. Finally, we introduce a cognitive relay scheme to improve interference coordination performance further. © 2013 IEEE.

Wang C.,Beijing University of Posts and Telecommunications
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We present an efficient entanglement concentration protocol (ECP) for electron spins based on quantum-dot and microcavity coupled systems. In our ECP, each two-electron spin system in a partially entangled state can be concentrated with the assistance of an ancillary quantum dot and a single photon, not two copies of two-electron spin systems. With current and near-future technology, the locally maximal entanglement of electron spins can be achieved, and our ECP can be used in long-distance quantum communications. © 2012 American Physical Society.

Jia H.,Beijing University of Posts and Telecommunications
Sensors and Transducers | Year: 2014

Limited display space of mobile devices is inadequate for simultaneous display of all the information needed in context. Practical guidelines for how to tailor information remain a longstanding challenge for mobile human-computer interaction (MHCI) optimization. With the help of RFID, GPS and sensors, mobile devices can perceive context of themselves. In this paper, principles of MHCI optimization for field mobile devices (FMD) from the perspective of distributed cognition theory and context-awareness technology is explored. Context factors which are perceived by FMD sensor networks and analyzed, based on which, we concluded the practical guidelines which are easy for people to implement MHCI optimization. We confirm the effectiveness of the guidelines by optimizing MHCI of FMD for a storage management system and illustrate how to utilize these design principles to support FMD HCI optimization and verify the effectiveness. At last we reassure the user experience with user experience testing for five dimensions of learnability, memorability, efficiency, error prevention and satisfaction. © 2014 IFSA Publishing, S. L.

Liu Y.-L.,Beijing University of Posts and Telecommunications
Applied Mechanics and Materials | Year: 2014

The optimization of wireless multipoint multimedia broadcasting system layered source transmission was studied and analyzed. The introduction of continuous layered source with superposition coding model infinite layer in this article, the optimal inter-layer power distribution function is given by variation method, then an average per user up to speed is obtained. In the simulation, the LSSC which introduces a layered source coding scheme compared with the traditional CB Scheme. LSSC transmit multiple data streams to meet different end user channel conditions is verified by the results. The problem of system performance loss due to channel asymmetry between the center of the cell edge users and users bring have been effective solved. © (2014) Trans Tech Publications, Switzerland.

Yang Y.-G.,Beijing University of Technology | Yang Y.-G.,Xidian University | Yang Y.-G.,University of Chinese Academy of Sciences | Wen Q.-Y.,Beijing University of Posts and Telecommunications
Optics Communications | Year: 2010

We give an arbitrated signature protocol of classical messages over a collective amplitude damping channel. We analyze its security and prove that it is secure over such a noisy quantum channel even if the arbitrator is compromised. The involvement of the arbitrator is also an appealing advantage in the implementation of a practical quantum distributed communication network. © 2010 Elsevier B.V. All rights reserved.

Liu L.,Beijing University of Posts and Telecommunications
Applied Mechanics and Materials | Year: 2014

Heterogeneous cellular network (HCN) is a key technology in the future mobile communication system. In this paper, the theoretical analysis results as a guide, HCN frequency resource allocation method based on ASID is proposed. The method first defines a macro base station receiver sensitivity loss limits, it uses the theory of direct communication users on average interference macro base stations closed expressions, then the radius of ASID is derived from the theoretical analysis. In conclusion, the rationality of frequency resource allocation method based on ASID by simulation is verification. © (2014) Trans Tech Publications, Switzerland.

Chen Z.,Peking University | Luo B.,Beijing University of Posts and Telecommunications | Guo H.,Peking University
Optics Express | Year: 2014

Absorption-free Bragg reflector has been studied in ions doped in crystals. We propose a new scheme using Zeeman sublevels of atoms to construct an absorption-free Bragg reflector with practical laser power. Its spatial period of refractive index equals half of the wavelength of the incident standing-wave coupling light. The proposal is simulated in a helium atom scheme, and can be extended to alkali earth atoms. © 2014 Optical Society of America.

Xia J.,Beijing University of Posts and Telecommunications
Telecommunications Policy | Year: 2011

Since the inception of telecom reform in 1994, structural reform has been a main thread surrounding the course of the development of Chinas telecommunications industry. In structuring the 2008 reform and the 2009 3G rollout Chinas government adopted a relatively balanced approach in the hope of creating level-playing-field in 3G era. Nevertheless, due to the presence of substantial switching costs, substitution effects from the present technology mode, that is, 2.5G, the absence of killer applications, among other technological and institutional factors, China may not have a realistic 3G era before moving toward 4G and beyond. At the bare minimum, currently there is a lacking of either adequate technological-push or demand-pull for a full-scale 3G commercializationthere is no sign that this situation will change in the near term. Triggered by recent initiatives of market convergence between the telecommunications, Internet, and cable, a renewed circle of market, and regulatory reform is probably necessary to cast a sounder industry basis for a timing migration toward the next-generation-networks (NGNs). The timing migration toward 4G (and beyond) may provide a chance for a late-mover nation like China to leapfrog its western counterparts in leading the industry in the era of NGNs. To this end, China is confronted with a challenge in re-examining its industry policy as well as technological strategies for a sustainable development in the era of NGNs. This study offers heuristic analysis and insights on the above issues based on archival documents and interviews. While implications are suggested for Chinas circumstances, the Chinese experiences may also be considered by other countries and investors when it comes to 3G (and beyond) policies, regulations, deployments, and evolutions. © 2010 Elsevier Ltd. All rights reserved.

Zhao C.,Inha University | Zhao C.,Beijing University of Posts and Telecommunications | Kwak K.,Inha University
IEEE Communications Letters | Year: 2010

The jointly optimal allocation of sensing time and power for a two-user amplify-and-forward overlay cognitive network is developed by maximizing the averaged aggregate throughput of the secondary network. In particular, observing that the sensing duration lies within a strict interval, the jointly optimal strategy of sensing time and power allocation is proved to be tractable by sequential optimization. © 2010 IEEE.

Tian L.,Beijing University of Posts and Telecommunications
Proceedings of 2nd International Conference on Computer Science and Network Technology, ICCSNT 2012 | Year: 2012

This paper briefly introduces the concept of the Internet of Things, the convergence trend analysis of the current situation of the mobile communication network and mobile communication network and the Internet of Things. It explores applications and prospects of the Internet of Things in the era of mobile communications from the telecom service providers' perspective. © 2012 IEEE.

Siyang Z.,Beijing University of Posts and Telecommunications
Proceedings - 2015 7th International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2015 | Year: 2015

This paper proposes a recognition algorithm for solving the puzzle of Quickly Response (QR) identification at highly deviated shooting angle. This algorithm includes five procedures, i.e. Binarization processing, edge detection, Hough transformation, morphological processing and projective geometry transformation, and it has been simulated and verified by Java language environment and android mobile terminal environment, and some operation had been implemented, such as write and find information by scanning or reading two-dimension code. © 2015 IEEE.

Peng M.,Beijing University of Posts and Telecommunications | Wang C.,Inter Digital Communications | Lau V.,Hong Kong University of Science and Technology | Poor H.V.,Princeton University
IEEE Wireless Communications | Year: 2015

As a promising paradigm for fifth generation wireless communication systems, cloud radio access networks (C-RANs) have been shown to reduce both capital and operating expenditures, as well as to provide high spectral efficiency (SE) and energy efficiency (EE). The fronthaul in such networks, defined as the transmission link between the baseband unit and the remote radio head, requires a high capacity, but is often constrained. This article comprehensively surveys recent advances in fronthaul-constrained CRANs, including system architectures and key techniques. Particularly, major issues relating to the impact of the constrained fronthaul on SE/EE and quality of service for users, including compression and quantization, large-scale coordinated processing and clustering, and resource allocation optimization, are discussed together with corresponding potential solutions. Open issues in terms of software-defined networking, network function virtualization, and partial centralization are also identified. © 2002-2012 IEEE.

Zhang B.,Beijing University of Posts and Telecommunications
Advanced Materials Research | Year: 2014

A new signal extracting approach is proposed to diagnose the weak response signal in the on-line motoring of robot. Taking a 3-D manipulator robot as the research object, this method combines nonlinear stochastic resonance method with chaotic oscillator to dispose the sampling signal and filter out false odd multiple frequencies. The useful signal is obtained in the strong noise. The experiment results show the application value of the method. © (2014) Trans Tech Publications, Switzerland.

Hua C.-C.,Beijing University of Posts and Telecommunications | Hua C.-C.,Yanshan University | Ding S.X.,University of Duisburg - Essen | Guan X.-P.,Yanshan University | Guan X.-P.,Shanghai JiaoTong University
Automatica | Year: 2012

This paper considers the controller design problem for a class of uncertain systems with unknown actuator parameters. The considered systems are with multiple time delays and nonlinear uncertainties, and the uncertain nonlinearities are bounded by nonlinear functions with unknown coefficients. The actuator parameters are time-varying and their bounds are unknown, moreover the signs of them are not available. To deal with unknown actuator parameters problem, we decompose the system into two subsystems. For the resultant system, we develop the corresponding tolerant controller design method with the help of Nussbaum function. By constructing the Lyapunov Krasovskii functional, we prove the asymptotical stability of the closed-loop system. Finally, simulations are performed on a chemical reactor system to show the effectiveness of the proposed method. © 2011 Elsevier Ltd. All rights reserved.

Zhu L.,Beijing University of Posts and Telecommunications
Proceedings of 2015 4th International Conference on Computer Science and Network Technology, ICCSNT 2015 | Year: 2015

Speaker clustering, in a speaker diarization system is of great importance since the result of speaker clustering impacts deeply on the final diarization result. However, errors can happen in every step in the clustering process, such as the estimation of the cluster number, the initialization of the cluster centers and so on. Therefore, it is necessary to modify the clustering result and improve the accuracy of the diarization system. In this paper, a modified clustering refinement approach based on cross EM refinement is presented to solve these issues. According to the experiment results, the performance of diarization result improved a lot with our modified refinement, and can handle much more badly speaker clustering results than the original cross EM refinement method. The experiments are carried out three datasets of different types-meeting, broadcast news and talk-show. © 2015 IEEE.

Si P.,Beijing University of Technology | Ji H.,Beijing University of Posts and Telecommunications | Yu F.R.,Carleton University | Leung V.C.M.,University of British Columbia
IEEE Transactions on Vehicular Technology | Year: 2010

Spectrum pooling in cognitive radio systems is an approach to manage the available spectrum bands from different licensed networks. Most previous work on spectrum pooling concentrates on the system architecture and the design of flexible-access algorithms and schemes. In this paper, we present a cooperative scheme for internetwork spectrum sharing among multiple secondary systems, which takes into account the price and spectrum efficiency as the design criteria. Specifically, the spectrum-sharing problem is formulated as a stochastic bandit system; thus, the optimal spectrum-sharing scheme is simply allocating the new available band to the secondary network with the lowest index. Extensive simulation examples illustrate that the proposed scheme significantly improves the performance compared with the existing scheme that ignores optimal spectrum sharing. © 2006 IEEE.

Qin W.,Tsinghua University | Qin W.,Tsinghua National Laboratory for Information Sciences and Technology | Wang C.,Beijing University of Posts and Telecommunications | Long G.L.,Tsinghua University | Long G.L.,Tsinghua National Laboratory for Information Sciences and Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

In this paper, we investigate a high-dimensional quantum state transfer protocol. An arbitrary unknown high-dimensional state can be transferred with high fidelity between two remote registers through an XX coupling spin chain of arbitrary length. The evolution of the state transfer is determined by the natural dynamics of the chain without external modulation and coupling strength engineering. As a consequence, entanglement distribution with a high efficiency can be achieved. Also the strong field and high spin quantum number can partly counteract the effect of finite temperature to ensure the high fidelity of the protocol when the quantum data bus is in the thermal equilibrium state under an external magnetic field. © 2013 American Physical Society.

Zhou J.,Shanghai JiaoTong University | Cao Z.,Harbin Institute of Technology | Dong X.,Harbin Institute of Technology | Lin X.,Beijing University of Posts and Telecommunications | Vasilakos A.,National Technical University of Athens
IEEE Wireless Communications | Year: 2013

M-healthcare mobile social network has emerged as a promising next-generation healthcare system increasingly adopted by the US and European governments, with the rapid development of sensor and wireless communication technologies. In this paper, we describe the goals and tactics, and present a distributed architecture of m-healthcare social networks. Following each kind of security and privacy challenge, we define a series of basic and sophisticated cyber attacks and give substantial and promising solutions to satisfy the unique security and privacy requirements in m-healthcare social networks. Last but not least, several interesting open problems are pointed out with possible addressing ideas to trigger more research efforts in this emerging area. © 2002-2012 IEEE.

Xin Y.,Beijing University of Posts and Telecommunications | Liu Z.,Shandong University | Zhang H.,Shandong University
Applied Optics | Year: 2012

Finger vein verification is a promising biometric pattern for personal identification in terms of security and convenience. The recognition performance of this technology heavily relies on the quality of finger vein images and on the recognition algorithm. To achieve efficient recognition performance, a special finger vein imaging device is developed, and a finger vein recognition method based on sparse representation is proposed. The motivation for the proposed method is that finger vein images exhibit a sparse property. In the proposed system, the regions of interest (ROIs) in the finger vein images are segmented and enhanced. Sparse representation and sparsity preserving projection on ROIs are performed to obtain the features. Finally, the features are measured for recognition. An equal error rate of 0.017% was achieved based on the finger vein image database, which contains images that were captured by using the near-IR imaging device that was developed in this study. The experimental results demonstrate that the proposed method is faster and more robust than previous methods. © 2012 Optical Society of America.

Liu J.,Beijing University of Posts and Telecommunications | Ansari N.,New Jersey Institute of Technology
Computer Communications | Year: 2014

With the rapid development of mobile devices and wireless technologies, mobile internet websites play an essential role for delivering networked services in our daily life. Thus, identifying website communities in mobile internet is of theoretical and practical significance in optimizing network resource and improving user experience. Existing solutions are, however, limited to retrieve website communities based on hyperlink structure and content similarities. The relationships between user behaviors and community structures are far from being understood. In this paper, we develop a three-step algorithm to extract communities by affinity measurement derived from user accessing information. Through experimental evaluation with massive detailed HTTP traffic records captured from a cellular core network by high performance monitoring devices, we show that our affinity measurement based method is effective in identifying hidden website communities in mobile internet, which have evaded previous link-based and content-based approaches. © 2014 Elsevier B.V. All rights reserved.

Shi D.,Beijing University of Posts and Telecommunications
Dianbo Kexue Xuebao/Chinese Journal of Radio Science | Year: 2011

Shielding effectiveness of enclosure with off-center aperture is investigated by using analytical method. Through modeling the shielding and propagation characteristic of enclosure with high order mode equivalent transmission line, the shielding effectiveness of enclosure with aperture is formulated when plane wave is incident with arbitrary incident angle and polarization direction. Relationship between shielding effectiveness and incident angle, polarization direction, aperture size, loss of enclosure wall, test point location and frequency are investigated. The result is verified by enclosure resonant theory. This analytical method with higher speed is suitable for parameter analysis and valuable for shielding enclosure design. © 2011 by Editorial Department of Chinese Journal of Radio Science.

Meng D.,Beihang University | Jia Y.,Beihang University | Du J.,Beijing University of Posts and Telecommunications | Yu F.,Henan Polytechnic University
Systems and Control Letters | Year: 2012

In this paper, the tracking control problem for multi-agent systems is considered, where all agents in a directed graph are enabled to track a time-varying reference trajectory perfectly over a finite interval. A unified algorithm is presented for agents described by both discrete-time and continuous-time models through using the iterative learning approach. Even under the condition that the reference trajectory is available to not all but only a portion of agents, all agents can be guaranteed to (1) obtain the finite-time tracking except the initial time step in the discrete-time domain and (2) follow the reference trajectory with constant shifts at all the time in the continuous-time domain. If an initial rectifying action is used to continuous-time agents, then the finite-time tracking can be derived on an interval that can be specified. The proposed algorithms are also extended to achieve the formation control for multi-agent systems. Moreover, design conditions are developed for all algorithms, and two examples are given to demonstrate the effectiveness of the theoretical results. © 2012 Elsevier Ltd. All rights reserved.

Xie N.,Shenzhen University | Xie N.,Beijing University of Posts and Telecommunications | Hu H.,Shenzhen University | Wang H.,Shenzhen University
Digital Signal Processing: A Review Journal | Year: 2012

The dithered signed-error constant modulus algorithm (DSE-CMA) is an approach less computationally than CMA but exhibits ill-convergence. On the contrary, the concurrent CMA with soft decision-directed scheme (CMA+SDD) improves the convergence rate of CMA by adding SDD but brings lots of computational complexity. As a tradeoff, in this paper we combine the virtues of DSE-CMA and SDD, then propose a new algorithm, which compensates the phase shift and provides convergence faster than DSE-CMA with lower complexity than CMA+SDD. More importantly, an approximation of its steady-state mean square error performance is derived. Simulation results show the superiority of the proposed algorithm. © 2010 Elsevier Inc.

Zhang H.,Beijing University of Posts and Telecommunications
Chinese Journal of Electronics | Year: 2015

Multicast has become increasingly important in multi-hop wireless networks for such applications which deliver shared media and data to multiple receivers. However, the existing multicast protocols for wireless network have large control overhead, and cannot adequately take the advantage of broadcast communication mode in multicast structure for sharing the forwarding path. This paper proposes a Cluster-based opportunistic multicast (COM) algorithm, which constructs multicast tree structure based on clusters by utilizing a stability greedy algorithm to achieve the minimum total Cluster-based expected transmission count (CETX). In this multicast tree structure, the edge is created between the kernel sets respectively belonging to two clusters for improving the forwarding efficiency and the stability of this structure. In the process of data distribution, our multi-layer solution combines multicast and opportunistic routing to improve the efficiency of transmission. Simulation results show that COM scheme can achieve the less total number of sending packets, and higher stability than other topology-based solutions and opportunistic multicast.

Ahmad T.,Iqra National University | Li X.,Beijing University of Posts and Telecommunications
Journal of Computational Information Systems | Year: 2012

In last few decades, number of efforts has been made to improve the visual quality of a degraded image. However, generating a desired high resolution image by means of the wavelet and other well-known transforms introduces many visual artifacts due to the Gibbs-like phenomena. In this paper, we propose a new algorithm based on curvelet transform to exploit its high energy compaction nature in order to reconstruct a high resolution image for the given low resolution input images. The low resolution images are first partially reconstructed by applying curvelet transform according to our proposed criteria. The proposed criteria are based on the calculated absolute kurtosis values of the input images. The partially reconstructed images are then registered using Marcel et. al. algorithm in spatial domain, which are then fused together using conventional POCS method. We apply our propose algorithm to the problem of restoring standard corrupt test images from noisy data and compare our results with those obtained via well-established technique. Our experiments show that the proposed algorithm outperforms the conventional super resolution technique both subjectively as well as in terms of the various estimation indices. Copyright © 2012 Binary Information Press.

Zheng Z.,Chinese University of Hong Kong | Zheng Z.,Beijing University of Posts and Telecommunications | Zhou T.C.,Chinese University of Hong Kong | Lyu M.R.,Chinese University of Hong Kong | And 2 more authors.
IEEE Transactions on Services Computing | Year: 2012

Cloud computing is becoming a mainstream aspect of information technology. More and more enterprises deploy their software systems in the cloud environment. The cloud applications are usually large scale and include a lot of distributed cloud components. Building highly reliable cloud applications is a challenging and critical research problem. To attack this challenge, we propose a component ranking framework, named FTCloud, for building fault-tolerant cloud applications. FTCloud includes two ranking algorithms. The first algorithm employs component invocation structures and invocation frequencies for making significant component ranking. The second ranking algorithm systematically fuses the system structure information as well as the application designers' wisdom to identify the significant components in a cloud application. After the component ranking phase, an algorithm is proposed to automatically determine an optimal fault-tolerance strategy for the significant cloud components. The experimental results show that by tolerating faults of a small part of the most significant components, the reliability of cloud applications can be greatly improved. © 2008-2012 IEEE.

Wang T.-Y.,Luoyang Normal University | Wen Q.-Y.,Beijing University of Posts and Telecommunications
Optics Communications | Year: 2011

In the comment, we show that the attack [G. Gao, Opt. Commun. 43 (2010) 902], which claims to be able to eavesdrop all the transmitted secret message of the improved three-party quantum secret sharing protocol [S. Lin, et al., Opt. Commun. 281 (2008) 4553], is invalid in the sense that it introduces 25% error rate. © 2011 Elsevier B.V. All rights reserved.

Chen X.,University of Melbourne | Li A.,University of Melbourne | Li A.,Center for Energy Efficient Telecommunications | Gao G.,University of Melbourne | And 4 more authors.
Optics Express | Year: 2011

In this paper we experimentally demonstrate transmission performance of optical DFT-spread OFDM systems in comparison with conventional OFDM systems. A 440.8-Gb/s superchannel consisting of 8 x 55.1-Gb/s densely-spaced DFT-S OFDM signal is successfully received after 1120-km transmission with a spectral efficiency of 3.5 b/s/Hz. It is shown that DFT-S OFDM can achieve an improvement of 1 dB in Q factor and 1 dB in launch power over conventional OFDM. Additionally, unique word aided phase estimation algorithm is proposed and demonstrated enabling extremely long OFDM symbol transmission. © 2011 Optical Society of America.

Wen F.,University of Jinan | Guo D.,University of Jinan | Li X.,Beijing University of Posts and Telecommunications
Applied Mathematics and Information Sciences | Year: 2014

In a recent paper (AMIS, 6(2S), 2012), Lee proposed a dynamic ID-based user authentication scheme based on smart card which is believed to have many abilities to resist a range of network attacks. In this paper, we analyze the security of Lee's scheme and show that the scheme is in fact insecure against insider-assisted attack, even if the adversary doesn't know the secret information stored in the smart card. In addition, the adversary can perform off-line guessing attack and impersonation attack if the secret information stored in the smart card is compromised. © 2014 NSP Natural Sciences Publishing Cor.

Chu X.,Kings College London | Wu Y.,Kings College London | Lopez-Perez D.,Kings College London | Tao X.,Beijing University of Posts and Telecommunications
IEEE Transactions on Wireless Communications | Year: 2011

Femtocells have been considered by the wireless industry as a cost-effective solution not only to improve indoor service providing, but also to unload traffic from already overburdened macro networks. Due to spectrum availability and network infrastructure considerations, a macro network may have to share spectrum with overlaid femtocells. In spectrum-sharing macro and femto networks, inter-cell interference caused by different transmission powers of macrocell base stations (MBSs) and femtocell access points (FAPs), in conjunction with potentially densely deployed femtocells, may create dead spots where reliable services cannot be guaranteed to either macro or femto users. In this paper, based on a thorough analysis of downlink (DL) outage probabilities (OPs) of collocated spectrum-sharing orthogonal frequency division multiple access (OFDMA) based macro and femto networks, we devise a decentralized strategy for an FAP to self-regulate its transmission power level and usage of radio resources depending on its distance from the closest MBS. Simulation results show that the derived closed-form lower bounds of DL OPs are tight, and the proposed decentralized femtocell self-regulation strategy is able to guarantee reliable DL services in targeted macro and femto service areas while providing superior spatial reuse, for even a large number of spectrum-sharing femtocells deployed per cell site. © 2011 IEEE.

Yang S.,University of Southampton | Lv T.,Beijing University of Posts and Telecommunications | Maunder R.G.,University of Southampton | Hanzo L.,University of Southampton
IEEE Transactions on Vehicular Technology | Year: 2011

A unified bit-based probabilistic data association (B-PDA) detection approach is proposed for multiple-input-multiple-output (MIMO) systems employing high-order rectangular quadrature amplitude modulation (QAM). The new approach transforms the symbol detection process of QAM to a bit-based process by introducing a unified matrix representation (UMR) of QAM. Both linear natural and nonlinear binary reflected Gray bit-to-symbol mappings are considered. With the aid of simulation results, we demonstrate that the linear-natural-mapping- based B-PDA approach typically attained an improved detection performance [measured in terms of both bit error ratio (BER) and symbol error ratio (SER)] in comparison with the conventional symbol-based probabilistic data association (PDA)-aided MIMO detector, despite its dramatically reduced computational complexity. The only exception is that, at low SNRs, the linear-natural-mapping- based B-PDA is slightly inferior in terms of its BER to the conventional symbol-based PDA using binary reflected Gray mapping. Furthermore, the simulation results show that the linear-natural-mapping-based B-PDA MIMO detector may approach the best-case performance provided by the nonlinear binary reflected Gray-mapping-based B-PDA MIMO detector under ideal conditions. Additionally, the implementation of the B-PDA MIMO detector is shown to be much simpler in the case of the linear natural mapping. Based on these two points, we conclude that, in the context of the uncoded B-PDA MIMO detector, it is preferable to use the linear natural bit-to-symbol mapping, rather than the nonlinear Gray mapping. © 2011 IEEE.

Wang L.,Beijing University of Posts and Telecommunications | Stuber G.L.,Georgia Institute of Technology
IEEE Network | Year: 2016

D2D communications has attracted substantial research attention recently due to its potential for improving spectrum and energy efficiency within existing cellular infrastructures. This work investigates methods for matching a DUE link (or links) to CUE to form spectrum sharing partners. The objective is to maximize various sum performance metrics (reward) of all D2D links and CUEs after successful pairing under individual power constraints. In our approach, a set of DUE candidates for each CUE uplink for a requisite SINR level is first identified, which allows us to form a bi-partite graph linking CUEs with their candidate DUE links for spectrum sharing. Classic algorithms, such as the Hopcroft-Karp, Gale-Shapley, and Kuhn-Munkres algorithms, are investigated for maximizing different performance metrics (reward) of all spectrum sharing CUEs and D2D links. Their performance is compared tp a low-complexity fairness-based algorithm that can deliver solid sum rate performance without high complexity. © 1986-2012 IEEE.

Li T.,Beijing Normal University | Yang G.-J.,Beijing Normal University | Deng F.-G.,Beijing Normal University | Deng F.-G.,Beijing University of Posts and Telecommunications
Optics Express | Year: 2014

Atomic ensembles are effective memory nodes for quantum communication network due to the long coherence time and the collective enhancement effect for the nonlinear interaction between an ensemble and a photon. Here we investigate the possibility of achieving the entanglement distillation for nonlocal atomic ensembles by the input-output process of a single photon as a result of cavity quantum electrodynamics. We give an optimal entanglement concentration protocol (ECP) for two-atomic-ensemble systems in a partially entangled pure state with known parameters and an efficient ECP for the systems in an unknown partially entangled pure state with a nondestructive parity-check detector (PCD). For the systems in a mixed entangled state, we introduce an entanglement purification protocol with PCDs. These entanglement distillation protocols have high fidelity and efficiency with current experimental techniques, and they are useful for quantum communication network with atomic-ensemble memories. © 2014 Optical Society of America.

Palushani E.,Technical University of Denmark | Mulvad H.C.H.,Technical University of Denmark | Kong D.,Technical University of Denmark | Kong D.,Beijing University of Posts and Telecommunications | And 3 more authors.
Optics Express | Year: 2014

We propose a simple OFDM receiver allowing for the use of standard WDM receivers to receive spectrally advanced OFDM signals. We propose to spectrally magnify the optical-OFDM super-channels using a spectral telescope consisting of two time-lenses, which enables reduced inter-carrier-interference in subcarrier detection by simple band-pass filtering. A demonstration on an emulated 100 Gbit/s DPSK optical-OFDM channel shows improved sensitivities after 4-times spectral magnification. ©2013 Optical Society of America.

Ma J.,Beijing University of Posts and Telecommunications
Optics Express | Year: 2014

The paper has theoretically evaluated a signal-signal beat interference (SSBI) cancellation receiver with the balanced detection (ICRBD) for single sideband optical orthogonal frequency division multiplexing (SSB-OOFDM) signal, which has an improved spectral efficiency (SE) by reducing the guard band (GB) between the OOFDM signal and the optical carrier. The influences of the parameters of the interleaver (IL), the optical coupler (OC), and the balanced photodiodes (BPD) as well as the connecting optical/electrical paths in the ICRBD on the received OFDM signal performance are studied in detail. The theoretical results show that the received OFDM signal and noise power are dependent on the parameters of the devices and their deviation away from the ideal value degrades the performance greatly. Based on the simulation system, the 40Gb/s 16QAM SSB-OOFDM signal with 5GHz GB is converted to the OFDM signal by the ICRBD with the suppressed SSBI. It is observed that (1) the received OFDM signal is insensitive to the deviation of the coupling coefficient of the 3dB OC; (2) the received signal suffers little degradation from the filter outline of the IL if an IL with the bandwidth over 13GHz and 6- or higher-order Gaussian filter is used; (3) the polarization deviation and phase shift between the OOFDM signal and the optical carrier caused by the optical paths between IL and OC have smaller influence on the EVM of the received signal; and (4) although the ICRBD is immune to the polarization deviation of the two recombined SSB-OOFDM signals, the relative time delay between the two optical/electrical paths from the OC to the BPD degrades the received signal seriously. By tuning the time delay in optical or electrical domain to reduce the total relative time delay within 10ps, the EVM maintains below 20%. The simulation results agree well with the theoretical analysis and catch an insight on the mechanism of the ICRBD. © 2014 Optical Society of America.

Lin S.,Fujian Normal University | Guo G.-D.,Fujian Normal University | Gao F.,Beijing University of Posts and Telecommunications | Liu X.-F.,Fujian Normal University
Quantum Information and Computation | Year: 2014

Decoherence-free subspace (DFS) is a valid solution to realize quantum communication over a collective noise channel, and has been widely studied. Generally speaking, replacing a qubit with a DFS state will cause the reduction of communication efficiency. However, in this letter, it is shown that some kinds of noises may not lower the transmission rate of quantum key distribution. To illustrate it, we propose two quantum key distribution protocols based on Bell states. Here, two nonorthogonal and unbiased sets in a DFS are constructed by linear combination of particles at different positions. Since n - 1 classical bits are distributed by using 2n qubits in our protocols, the transmission rate is close to that of noiseless BB84 protocol. Furthermore, when considering the cost of transmitting classical bits, the efficiencies of these protocols are even higher than that of BB84 protocol. © Rinton Press.

Hu H.,Technical University of Denmark | Kong D.,Technical University of Denmark | Kong D.,Beijing University of Posts and Telecommunications | Palushani E.,Technical University of Denmark | And 3 more authors.
Optics Express | Year: 2014

We have demonstrated the generation of a 320 Gb/s Nyquist-OTDM signal by rectangular filtering on an RZ-OTDM signal with the filter bandwidth (320 GHz) equal to the baud rate (320 Gbaud) and the reception of such a Nyquist-OTDM signal using polarization-insensitive time-domain optical Fourier transformation (TD-OFT) followed by passive filtering. After the time-to-frequency mapping in the TD-OFT, the Nyquist-OTDM signal with its characteristic sinc-shaped time-domain trace is converted into an orthogonal frequency division multiplexing (OFDM) signal with sinc-shaped spectra for each subcarrier. The subcarrier frequency spacing of the converted OFDM signal is designed to be larger than the transform-limited case, here 10 times greater than the symbol rate of each subcarrier. Therefore, only passive filtering is needed to extract the subcarriers of the converted OFDM signal. In addition, a polarization diversity scheme is used in the four-wave mixing (FWM) based TD-OFT, and less than 0.5 dB polarization sensitivity is demonstrated in the OTDM receiver. ©2013 Optical Society of America.

Zhao X.,Beijing University of Posts and Telecommunications | Wang S.,CAS Academy of Mathematics and Systems Science | Lai K.K.,City University of Hong Kong
Expert Systems with Applications | Year: 2011

This paper proposes two quadratic-constrained DEA models for evaluation of mutual funds performance, from a perspective of evaluation based on endogenous benchmarks. In comparison to previous studies, this paper decomposes two vital factors for mutual funds performance, i.e. risk and return, in order to define mutual funds' endogenous benchmarks and give insights and suggestions for managements. Of the two quadratic-constrained DEA models, one is a partly controllable quadratic-constrained programming. The approach is illustrated by a sample of twenty-five actual mutual funds operating in the Chinese market. It identifies the root reasons of inefficiency and ways for improving performance. The results show that although the market environment in year 2006 was much better than that in 2005, average efficiency score declines in year 2006 due to relaxing of system risk control. The majority of mutual funds do not show persistence in efficiency ranking. The most important conclusion is that the ranking of mutual funds in China depends mostly on system risk control. © 2010 Elsevier Ltd. All rights reserved.

Zhou Y.-J.,Beijing University of Posts and Telecommunications | Liu J.,Xidian University
Beijing Youdian Daxue Xuebao/Journal of Beijing University of Posts and Telecommunications | Year: 2010

In order to solve the problem of the blind recognition of channel coding, a blind recognition method of identifying (n-1)/n convolution code is proposed. Firstly, a mathematical model of blind recognition is given, followed by a method of solving parity check matrix through decomposition of the matrix constructed by the intercepted code. Meanwhile, by the elementary transform of the parity check matrix, the blind recognition of convolution code can be achieved. Simulations show that the proposed method can recognize the convolution code parameters effectively.

Yang Y.-G.,Beijing University of Technology | Xia J.,Beijing University of Technology | Jia X.,Beijing University of Technology | Zhang H.,Beijing University of Posts and Telecommunications
Quantum Information Processing | Year: 2013

A novel gray-level image encryption/decryption scheme is proposed, which is based on quantum Fourier transform and double random-phase encoding technique. The biggest contribution of our work lies in that it is the first time that the double random-phase encoding technique is generalized to quantum scenarios. As the encryption keys, two phase coding operations are applied in the quantum image spatial domain and the Fourier transform domain respectively. Only applying the correct keys, the original image can be retrieved successfully. Because all operations in quantum computation must be invertible, decryption is the inverse of the encryption process. A detailed theoretical analysis is given to clarify its robustness, computational complexity and advantages over its classical counterparts. It paves the way for introducing more optical information processing techniques into quantum scenarios. © 2013 Springer Science+Business Media New York.

We analyzed the different biological processes and occurrence numbers between low expression inhibited PTHLH downstream-mediated aging gene ontology (GO) network of no-tumor hepatitis/cirrhotic tissues (HBV or HCV infection) and the corresponding high expression (fold change ≥2) inhibited GO network of human hepatocellular carcinoma (HCC). Inhibited PTHLH downstream-mediated aging network consisted of aging, branched chain family amino acid biosynthesis, cellular metabolism, cholesterol biosynthesis, coupled to cyclic nucleotide second messenger, cytolysis, 'de novo' GDP-l-fucose biosynthesis, detection of mechanical stimulus, glucose homeostasis, G-protein signaling, leukocyte adhesion, iron-sulfur cluster assembly, JAK-STAT cascade, Notch signaling pathway, nucleotide-sugar metabolism, peptidyl-tyrosine sulfation, protein amino acid N-linked glycosylation, protein amino acid phosphorylation, response to drug, rRNA processing, translational initiation, ubiquitin-dependent protein catabolism, homophilic cell adhesion in no-tumor hepatitis/cirrhotic tissues. We proposed inhibited PTHLH downstream leukocyte adhesion-mediated protein amino acid N-linked glycosylation coupling Notch and JAK-STAT cascade to iron-sulfur cluster assembly-induced aging network. Our hypothesis was verified by the same inhibited PTHLH downstream-mediated aging GO network in no-tumor hepatitis/cirrhotic tissues with the corresponding activated GO network of HCC, or the different with the corresponding activated GO network of no-tumor hepatitis/cirrhotic tissues. Inhibited PTHLH downstream leukocyte adhesion-mediated protein amino acid N-linked glycosylation coupling Notch and JAK-STAT cascade to iron-sulfur cluster assembly-induced aging network included TSTA3, ALK, CIAO1, NOTCH3 in no-tumor hepatitis/cirrhotic tissues from the GEO data set using gene regulatory network inference method and our programming.

Yu Y.,Beijing University of Posts and Telecommunications
Chinese Journal of Electronics | Year: 2013

In digital communications, the channel affects the transmitted sequence with both linear and nonlinear distortions. We address the blind detection over time-varying frequency-selective and nonlinear channels in this paper. A blind detector is derived within the Bayesian framework and implemented via the Particle filtering (PF) method. The proposed PF-based detector incorporates auxiliary PF strategy and a hybrid importance distribution to improve the efficiency and effectiveness. A delayed-weight estimation method is also presented to further improve the performance of the detector. Simulations are provided that demonstrate the performance of the detector under different system settings.

Cui M.,Key Laboratory of Cluster Science | Cui M.,Hebei University of Science and Technology | Xu B.,Beijing University of Posts and Telecommunications | Hu C.,Key Laboratory of Cluster Science | And 2 more authors.
Electrochimica Acta | Year: 2013

Direct electrochemistry of glucose oxidase (GOD) on three-dimensional (3D) interpenetrating porous graphene electrodes has been reported, which have been fabricated by one-step electrochemical reduction of graphene oxide (GO) from its aqueous suspension. The electrochemically reduced GO (ERGO) modified electrodes exhibited excellent electron transfer properties for GOD and enhanced the enzyme activity and stability by the assistance of chitosan. The immobilized GOD shows a fast electron transfer with the rate constant (ks) of 6.05 s-1. It is worth mentioning that in the air-saturated phosphate buffer solution without any mediator, the resultant modified electrodes exhibited low detection limit of 1.7 μM with wide linear range of 0.02-3.2 mM and high sensitivity and high selectivity for measuring glucose. It would also be extended to various enzymes and bioactive molecules to develop the biosensor or other bio-electrochemical devices. © 2013 Elsevier Ltd. All rights reserved.

Yuan W.,Guangzhou University | Li Y.,Beijing University of Posts and Telecommunications | Lin J.,Guangzhou University of Chinese Medicine
Mathematical Methods in the Applied Sciences | Year: 2013

In this paper, we employ the complex method to obtain first all meromorphic solutions of an auxiliary ordinary differential equation and then find all meromorphic exact solutions of the classical Korteweg-de Vries equation, Boussinesq equation, (3 + 1)-dimensional Jimbo-Miwa equation, and Benjamin-Bona-Mahony equation. Our results show that the method is more simple than other methods. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.

Yao Z.C.,Beijing University of Posts and Telecommunications
Applied Mechanics and Materials | Year: 2014

This paper introduces the software radio technology model and multi mode modem technology based on software radio, and analyzed and designed in detail the multi mode modem technology and current communication field, finally, and it is realize on the FPGA. Multi mode modem greatly improving communication system reliability, flexibility, increase system capacity, will have broad market prospect. © (2014) Trans Tech Publications, Switzerland.

Rangayyan R.M.,University of Calgary | Wu Y.,Beijing University of Posts and Telecommunications
Biomedical Signal Processing and Control | Year: 2010

Pathological conditions of knee joints have been observed to cause changes in the characteristics of vibroarthrographic (VAG) signals. Several studies have proposed many parameters for the analysis and classification of VAG signals; however, no statistical modeling methods have been explored to analyze the distinctions in the probability density functions (PDFs) between normal and abnormal VAG signals. In the present work, models of PDFs were derived using the Parzen-window approach to represent the statistical characteristics of normal and abnormal VAG signals. The Kullback-Leibler distance was computed between the PDF of the signal to be classified and the PDF models for normal and abnormal VAG signals. Additional statistical measures, including the mean, standard deviation, coefficient of variation, skewness, kurtosis, and entropy, were also derived from the PDFs obtained. An overall classification accuracy of 77.53%, sensitivity of 71.05%, and specificity of 82.35% were obtained with a database of 89 VAG signals using a neural network with radial basis functions with the leave-one-out procedure for cross validation. The screening efficiency was derived to be 0.8322, in terms of the area under the receiver operating characteristics curve. © 2009 Elsevier Ltd. All rights reserved.

The rapid growth of visualization technologies and Cloud computing have opened a new paradigm for utilizing the existing resource pools for on-demand and scalable computing, which enables the workflow management system to meet quality-of-service (QoS) requirements of the applications. It becomes crucial for cloud customers to choose the best Cloud services in order to minimize the running costs, and how to match and select the optimum cloud service will be a challenge problem. In this paper, we present an efficient Cloud services workflow scheduling and optimization schema using heuristic generic algorithm, and focus on the hierarchical Cloud service workflow scheduling, Cloud workflow tasks parallel split, syntax and semantic based Cloud workflow tasks matching algorithm, and multiple QoS constraints based Cloud workflow scheduling and optimization, and also presents the experiment conducted to evaluate the efficiency of our algorithm.

Li Y.,Chinese Peoples Liberation Army | Wen Q.,Beijing University of Posts and Telecommunications | Zhang B.,Chinese Peoples Liberation Army
Nonlinear Dynamics | Year: 2012

Chaotic ant swarm optimization (CASO) is a powerful chaos search algorithm for optimization problems, but it is often easy to be premature convergence. To overcome the weakness, this paper presents a CASO with passive congregation (CASOPC). Passive congregation is one type of biological information sharing mechanisms that allow animals to aggregate into groups and help to enhance the exploitation of animals. By introducing passive congregation strategy into the CASO, a modified evolution equation based on the CASO is proposed in the CASOPC. The modified evolution equation cannot only employ the parallel search of all ants and the well exploration ability of the CASO, but also stress and control the exploitation by passive congregation coefficient c in the stage of evolution. Due to linearly increasing c in the CASOPC, the exploration and exploitation ability of ants are well balanced so that premature convergence can be avoided and good performance can be achieved. In order to estimate the capability of the CASOPC, it is tested with a set of 5 benchmark functions with 30 dimensions and compared to the CASO. Experimental results indicate that the CASOPC improves the search performance on the benchmark functions significantly. © 2011 Springer Science+Business Media B.V.

Gao Y.,Beijing University of Posts and Telecommunications | Jiang Y.,Norwegian University of Science and Technology
IEICE Transactions on Communications | Year: 2012

In this paper, performance analysis of a cognitive radio network is conducted. In the network, there is imperfect sensing and the wireless channel is a Gilbert-Elliott channel. The focus is on the network's capacity in serving traffic with delay constraints. Specifically, the maximum traffic arrival rates of both primary users and secondary users, which the network can support with guaranteed delay bounds, are investigated. The analysis is based on stochastic network calculus. A general relationship between delay bounds, traffic patterns and important characteristics such as spectrum sensing errors and channel fading of the cognitive radio network is derived. This relationship lays a foundation for finding the capacity under different traffic scenarios. Two specific traffic types are exemplified, namely periodic traffic and Poisson traffic. Analytical results are presented in comparison with simulation results. The comparison shows a good match between them, validating the analysis. © 2012 The Institute of Electronics, Information and Communication Engineers.

Chen R.Y.,Beijing University of Posts and Telecommunications
Applied Mechanics and Materials | Year: 2014

The progress and development of the society promotes service industry to grow, and service-oriented enterprises are emerging. However, the lagging service theory makes the development of service economy lack of the corresponding theoretical support. Based on analyzing the sources of corporate profits in service economy era, the paper uses data mining technique to apply customer classification to measurement methods of service capability. The change of service capability not only makes the enterprises position the problem clients accurately and rapidly, but also can timely adjust business strategies, which can increase profits. © (2014) Trans Tech Publications, Switzerland.

Zhang B.,Beijing University of Posts and Telecommunications
CCIS2011 - Proceedings: 2011 IEEE International Conference on Cloud Computing and Intelligence Systems | Year: 2011

With the proliferation of Web services and the evolution towards the Semantic Web comes the opportunity to automate various Web services tasks. In this paper, we propose the conception of Sub Web Service and present an algorithm of automatic web service composition which based on Sub Web Service. The most contribution of this paper is: (1) propose the conception of Sub Web Service; (2) present a automatic composition algorithm. The simulation experiment indicated that the algorithm we proposed is effective and efficiency when applied in web service composition engine. © 2011 IEEE.

Zhang G.,CAS Institute of Microelectronics | Zuo X.,Beijing University of Posts and Telecommunications
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

Public cloud providers provide Infrastructure as a Service (IaaS) to remote users. For IaaS providers, how to schedule tasks to meet peak demand is a big challenge. Previous researches proposed purchasing machines in advance or building cloud federation to resolve this problem. However, the former is not economic and the latter is hard to be put into practice at present. In this paper, we propose a hybrid cloud architecture, in which an IaaS provider can outsource its tasks to External Clouds (ECs) without establishing any agreement or standard when its local resources are not sufficient. The key issue is how to allocate users' tasks to maximize its profit while guarantee QoS. The problem is formulated as a Deadline Constrained Task Scheduling (DCTS) problem which is resolved by standard particle swarm optimization (PSO), and compared with an exact approach (CPLEX). Experiment results show that Standard-PSO is very effective for this problem. © 2013 Springer-Verlag Berlin Heidelberg.

Zhang X.-G.,Beijing University of Posts and Telecommunications
Beijing Youdian Daxue Xuebao/Journal of Beijing University of Posts and Telecommunications | Year: 2011

Polarization effect plays a main role in high speed optical communications. The polarization states in fibers must be controlled effectively. The related concepts, the present status of research, the latest progress, and future research trends in the polarization effect controls is presented, including polarization stabilization, de-multiplexing for polarization multiplexing system, as well as mitigation or compensation for polarization mode dispersion in fibers. The achievements of these three technologies are also described.

Ren X.-M.,Beijing University of Posts and Telecommunications
Beijing Youdian Daxue Xuebao/Journal of Beijing University of Posts and Telecommunications | Year: 2015

Based on the fundamental concept of the author's bivergentum theory and therein the attempt of the extension of Einstein's special theory of relativity (or called as “high-speed special theory of relativity”, ESTR or HS-STR), which shows the relationship between the matter movement and the space-time status mainly in the super-high speed regime, with the consequence of having predicted the low-speed special relativistic effect which may exist explicitly in the super-low speed regime and, furthermore, the full-velocity-scope special relativistic effect which may exist explicitly in both the super-high speed and the super-low speed regimes and also involves the in-between common speed regime, some comments, queries and modifications on the hypotheses of ESTR are made and the main points therein are as follows: First of all, it is pointed out that the so called “principle of special relativity (PSR)” which was adopted as one of the hypotheses in Einstein's derivation for the establishment of ESTR surpasses the purest-sense principle of special relativity, because it contains actually but implicitly the independent principle of Galileo-limit correspondence and the independent assumption of linear time-space transformation (TST), both being of, at least potentially, the lack of generality. Secondly, it is realized that the principle of constancy of light velocity (PCLV) which was revealed from the observation of the movement of electromagnetic waves as well as the PSR seems to be limited to some extent in its worthiness, while, based on the observation of the movement of the real physical objects, it would be possible to find some proper principle or principles which could be equivalent to or even more general than the PCLV so that could be taken as relevant hypothesis or hypotheses of the special theory of relativity (STR), and then more insightful and more comprehensive physical essences of the relativistic effects could be reflected and some significant changes of STR could be induced; Thirdly, the PCLV and the individual principle of intrinsic constant-velocity of light are differentiated, and it is found that the PSR resides not only in the high-level symmetries of relevant TST expressions but definitely also in other principles related to some physical processes; Fourthly, the STR hypotheses are updated according to the recent research advancements, i.e. the PCLV is sublated by replacing it with the previously proposed principle of upwards and downwards dual limitations of velocity which means that there exist both upper and lower velocity limits for real physical objects and also with the relevant twinborn principle of mass-velocity dependence (PMVD); Meanwhile, for possible changes of the STR expected by the author, the necessity of proper utilization of the principle of Galileo-limit correspondence or the extension from this principle to the principle of Lorentz-limit correspondence and even to the principle of general limit correspondence in which the concreteness of each individual limit is sublated and also the necessity of giving up the assumption of linear TST and turning to referring to the principle of the mathematical-form openness of TST are clarified. On the basis of these understandings, the expressions of Lorentz transformation in ESTR is re-derived by introducing the PMVD under the approximation of the mono-upwards-limitation of velocity; the concrete way to do this kind of derivations by replacing the PCVL with the PMVD is demonstrated; and, the observation of the constancy of light velocity (or, the constancy of the upper-limit velocity) is made to degenerate from a hypothesis into a deducted consequence in ESTR. Then, the phenomenological derivations of the mass-velocity dependences under the approximations of the mono-upwards and mono-downwards limitations of velocity are given respectively; the principles of the establishments of the expressions of TSTs in low-speed STR and in full-velocity-scope STR are also given. This work makes the establishment of the complete theoretical model of the full-velocity-scope STR go ahead for one more step. ©, 2015, Beijing University of Posts and Telecommunications. All right reserved.

Ren X.-M.,Beijing University of Posts and Telecommunications
Beijing Youdian Daxue Xuebao/Journal of Beijing University of Posts and Telecommunications | Year: 2015

The validity of the expressions of the full-cosmic-scope wave-particle duality in the bivergentum theory previously proposed by the author is reviewed, the wave property and the particle property of bivergentums, the abstracted existences of the real physical objects in microscopic, mesoscopic and macroscopic regimes, are intensively investigated and the new conclusion is worked out, i.e. the natural measure of the wave-property level should be the energy residing in unity frequency or the momentum residing in unity wave-number and the natural measure of the particle-property level should be the frequency corresponding to unit energy and the wave-number corresponding to unit momentum. Moreover, a new point of view that the full-cosmic-scope quantization variable takes its minimum value at the macroscopic limit is proposed and the definitions of the “bipolar-ly normalized” wave-property level as well as the same kind of partical-property level are given so that the understanding of the full-cosmic-scope wave-particle duality is improved. Afterwards, the full-cosmic-scope uncertainty principle proposed by the author is modified according to the new point of view. Meantime, the understanding of symitons (a kind of matters predicted by the author) is deepened, the inevitability and the basic rules of the mutual conversion between photons and symitons are pointed out, the quantitative relation between the upper and lower limits of the full-cosmic-scope quantization variable is derived, three typical physical processes, i.e. the spontaneous emission, the stimulated emission and the stimulated absorption, have been interpreted upon the new basis, the relevant fourth physical process is predicted, and the extended Einstein relations including all the four physical processes are given. Consequently, the probabilities of the “lasing” of symitons and the realization of “super-slow light” are deduced. Finally, it is assumed that the probability-wave behavior of every bivergentum originates from the vacuum fluctuation of quantum field. All these works make the bivergentum theory improved towards perfect, and the theory on the mutual interaction between light and matters is extended to the theory on the multi-factor interaction between photons, symitons and matters. ©, 2015, Beijing University of Posts and Telecommunications. All right reserved.

Zheng K.,Beijing University of Posts and Telecommunications
Proceedings - 2015 11th International Conference on Computational Intelligence and Security, CIS 2015 | Year: 2015

In this paper, the SIMPLIcity (Semantics-sensitive Integrate Matching for Picture Libraries), an image retrieval system is introduced. The feature extraction is based on Histogram, color layout and coefficients of wavelet transform. This retrieving system adopts feature database for matching so as to reduce the search space which is especially useful in a larger image database. Retrieval images are selected according to the closest similar measures computed by distance. Under experiments of 600 medical images, this method shows a higher performance of matching. And the similarity defined by l1 for searching is more suitable for gray images. © 2015 IEEE.

Zhang C.,Beijing University of Posts and Telecommunications
Proceedings - 25th IEEE International Conference on Advanced Information Networking and Applications Workshops, WAINA 2011 | Year: 2011

An adaptive Genetic Algorithm is presented to select optimal web service composite plan from a lot of composite plans on the basis of global Quality-of-Service (QoS) constraints. In this Genetic Algorithm, a population diversity measurement and an adaptive crossover strategy are proposed to further improve the efficiency and convergence of Genetic Algorithm. The probability value of the crossover operation can be set according to the combination of population diversity and individual fitness. The algorithm can get more excellent composite service plan because it accords with the characteristic of web service selection very well. Some simulation results on web service selection with global QoS constraints have shown that the adaptive Genetic Algorithm can gain quickly better composition service plan that satisfies the global QoS requirements. © 2011 IEEE.

Mao X.,Tsinghua University | Tang S.,Illinois Institute of Technology | Xu X.,Illinois Institute of Technology | Li X.-Y.,Tsinghua University | Ma H.,Beijing University of Posts and Telecommunications
IEEE Transactions on Parallel and Distributed Systems | Year: 2011

Opportunistic routing [2], [3] has been shown to improve the network throughput, by allowing nodes that overhear the transmission and closer to the destination to participate in forwarding packets, i.e., in forwarder list. The nodes in forwarder list are prioritized and the lower priority forwarder will discard the packet if the packet has been forwarded by a higher priority forwarder. One challenging problem is to select and prioritize forwarder list such that a certain network performance is optimized. In this paper, we focus on selecting and prioritizing forwarder list to minimize energy consumption by all nodes. We study both cases where the transmission power of each node is fixed or dynamically adjustable. We present an energy-efficient opportunistic routing strategy, denoted as EEOR. Our extensive simulations in TOSSIM show that our protocol EEOR performs better than the well-known ExOR protocol (when adapted in sensor networks) in terms of the energy consumption, the packet loss ratio, and the average delivery delay. © 2011 IEEE.

Jianfeng Q.,Beijing University of Posts and Telecommunications
International Journal of Control and Automation | Year: 2014

It is the common issue for all of countries that lots of safety risk accidents happen in large scale engineering projects. To save cost, generally, no enough resource is booked, or not very qualified resource is selected, which is one of the import safety risk factors in large scale engineering projects. But less scientific strategies are available to balance between safety risk values and safety risk investment. In the large scale engineer safety risk management filed, currently most of methods are qualitative, so it is a hot and difficult topic that constructs a quantitative model for practical problems, especially based on optimal control theory. In this paper, we will take both advantages of maximum principle and dynamic programming to solve the large scale engineering project safety risk issues caused by resource numbers and resource quality. Firstly, by maximum principle, establishes safety risk model considering resource numbers, and give iterative steps of the gradient descent method for numerical solution; Secondly, by dynamic programming, establishes safety risk economic model which takes into account the quality of resource; In the end, both the models are validated in one practical equipment case by combining the advantages of each algorithms. © 2014 SERSC.

Zhang B.,Beijing University of Posts and Telecommunications
IET Conference Publications | Year: 2010

With the proliferation of Web services and the evolution towards the Semantic Web comes the opportunity to automate various Web services tasks. A number of approaches have been proposed to tackle the problem of automatic web service composition. Most of them are inspired by the researches in AI planning. As heuristics plays a key role in the promotion of planning efficiency, the selection of heuristic mechanism is very important. In this paper, we propose the conception of composition distance, and propose a heuristic bidirectional search algorithm based on composition distance. The most contribution of this paper is: (1)propose the conception of composition distance; (2)a heuristic bidirectional search algorithm. The algorithm we proposed is effective and efficiency when applied in web service composition engine.

Guo J.,Beijing University of Posts and Telecommunications | Guo H.,University of Southern California | Wang Z.,China Mobile
PLoS ONE | Year: 2014

The temporal order of cancer gene mutations in tumors is essential for understanding and treating the disease. Existing methods are unable to infer the order of mutations that are identified at the same time in individual tumor samples, leaving the heterogeneity of the order unknown. Here, we show that through a complex network-based approach, which is based on the newly defined statistic -carcinogenesis information conductivity (CIC), the temporal order in individual samples can be effectively inferred. The results suggest that tumor-suppressor genes might more frequently initiate the order of mutations than oncogenes, and every type of cancer might have its own unique order of mutations. The initial mutations appear to be dedicated to acquiring the function of evading apoptosis, and some order constraints might reflect potential regularities. Our approach is completely data-driven without any parameter settings and can be expected to become more effective as more data will become available. © 2014 Guo et al.

Fu X.,Beihang University | Jia Y.,Beihang University | Du J.,Beijing University of Posts and Telecommunications | Yu F.,Henan Polytechnic University
IET Control Theory and Applications | Year: 2010

This study is devoted to the problem of state estimation of discrete-time stochastic systems with Markov switching parameters. Three improved interacting multiple model (IMM) algorithms for manoeuvring target tracking are presented, in which the filter outputs are combined based on three optimal multi-model fusion criterions weighted by scalars, diagonal matrices and general matrices, respectively. The proposed algorithms can receive the optimal state estimations of target in the linear minimum variance sense. It is proved that the traces of variance matrices of tracking errors in three proposed algorithms are less than the trace in the classical IMM algorithm. Extensive Monte Carlo simulations verify that the proposed algorithms are effective and have an absolute advantage in the velocity estimation. In particular, one of the proposed algorithms is obviously better than the IMM algorithm in accuracy and elapsed time and, therefore, can be a competitive alternative to the classical IMM algorithm for the tracking of manoeuvring target in real time. © 2010 The Institution of Engineering and Technology.

Kang G.,Beijing University of Posts and Telecommunications
2012 IEEE 14th International Conference on e-Health Networking, Applications and Services, Healthcom 2012 | Year: 2012

Recently, the R&D and applications of M2M systems are booming in China, especially after it is written in the 2010 Government Work Report. In this paper, the R&D works of wireless eHealth (WeHealth) are overviewed, the concept of which was proposed by our group in 2005. Some key techniques of WeHealth system are discussed, and some practices based on the concept of WeHealth are introduced. Besides, a recent WeHealth pilot trial on chronic disease monitoring is also introduced, which is reported as "The First Wireless Healthcare Chronic Disease Monitoring Project in China Based on Internet of Things Technology". There are 30 community hospitals up to now applying our WeHealth blood pressure monitoring system for chronic disease management. The practical data clearly demonstrate the effectiveness of our WeHealth system in hypertension disease control. © 2012 IEEE.

Wang T.,Beijing University of Posts and Telecommunications
International Journal of Multimedia and Ubiquitous Engineering | Year: 2015

General warning method of electronic banks generates based on clear detection of relevant data. However, this method is mostly a reflection of electronic banks’ risks in the past which is a manifestation of historical data that can only be able to analyze problems that have already occurred but can not give a better future anticipation. Therefore early warning system established in this paper is based on the data detection system and we use an optimized gray early warning method to predict the indicators of the risk of electronic banks. Based on the idea of using descending cumulation to change traditional gray 1-AGO sequence, we use weaken buffer operators to deal with the original data sequence and then use genetic algorithm to estimate a and b--important parameters of background values. Eventually the optimized gray GM (1,1) model prediction method generate and it can effectively forecast the risk profile of electronic banks. Then analyze the results, further read and dig the hidden meaning, give a series of practical conclusions for the development, risk prevention and control of electronic banks. Decision making depends on the degree of risk in the future. Then we can take effective measures to cope with the arrival of electronic bank crisis that may arise. © 2015 SERSC.

A full-duplex radio-over fiber (RoF) link scheme based on single sideband (SSB) optical millimeter (mm)-wave signal with polarization-rotated optical carrier is proposed to realize the source-free colorless base station (BS), in which a polarization beam splitter (PBS) is used to abstract part of the optical carrier for conveying the uplink data. Since the optical carrier for the uplink does not bear the downlink signal, no cross-talk from the downlink contaminates the uplink signal. The simulation results demonstrate that both down- and up-links maintain good performance. The mm-wave signal distribution network based on the proposed full duplex fiber link scheme can use the uniform source-free colorless BSS, which makes the access system very simpler. © 2016 Elsevier Inc.

Wang J.,Beijing University of Posts and Telecommunications
Proceedings - 2010 2nd International Conference on Multimedia Information Networking and Security, MINES 2010 | Year: 2010

In a wireless sensor network (WSN), the sensors closest to the sink tend to deplete their energies faster than the other sensors, which is known as an energy hole around the sink. To avoid this, a new scheme for placing nodes, via adjusting surface densities and initial energies in each ring in a ring model, is proposed in this paper. A new definition of network efficiency, including the consideration of energy cost, is also introduced and applied. The simulation results demonstrate that this scheme can significantly increase the network efficiency compared with the uniform placement algorithm, especially when the size of the network is relatively large. © 2010 IEEE.

Liang X.,University of Waterloo | Zhang K.,University of Waterloo | Shen X.,Dalian Maritime University | Lin X.,Beijing University of Posts and Telecommunications
IEEE Wireless Communications | Year: 2014

Mobile social networking is a pervasive communication platform where users with smartphones can search over the Internet and query neighboring peers to obtain the desired information. In this article, we examine the architecture, communication patterns, and especially the security and privacy of MSN. We first study three categories of mobile applications with a focus on two autonomous mobile applications, business card and service review. We then explore the possible methods to deal with the associated security and privacy challenges. By discussing the shortages of the methods, we finally provide several promising research directions. © 2014 IEEE.

Tong H.,Shanghai University | Tong H.,Beijing University of Posts and Telecommunications
Journal of Systems Science and Complexity | Year: 2012

C is an [n, k, d] q linear code over F q. And s(C) = n + 1 - k - d is the Singleton defect of C. AnMDS code C with s(C) = 0 has been studied extensively. Recently, a near-MDS code C with s(C) = s(C ⊥) = 1 is studied by many scholars, where C ⊥ denotes the dual code of C. This paper concentrates on the linear code C with s(C) = s(C ⊥) = 2, and the author calls it an NNMDS code. A series of iff conditions of NNMDS codes are presented. And the author gives an upper bound on length of NNMDS codes. In the last, some examples of NNMDS are given. © 2012 Institute of Systems Science, Academy of Mathematics and Systems Science, CAS and Springer-Verlag Berlin Heidelberg.

Xia J.,Beijing University of Posts and Telecommunications
Telecommunications Policy | Year: 2012

When it comes to the analysis of the intrinsic mechanism of market behaviors and hence competition development and regulatory imperatives in the Chinese telecommunications industry, currently there is no consistent pattern offered in the literature. In Chinas emergent 3G/4G era, market behaviors can be affected by various institutional factors, along with various forms of informal forces, which may translate into different implications for competition regulation. Based on extensive archival research and interview, this current study aims to bridge the gap by following an interpretive approach. An input-output model was substantiated for pattern-matching in the Chinese context base on the postulation of a series of propositions and hence Industry-Gray-Box. Accordingly, two categories of market behaviors, that is, market-driven vs. institutions-driven, were arguably delineated as being underpinning the competition development. Policy implications and future reform imperatives were discussed. This study may advance knowledge in terms of: (1) the establishment of a relatively consistent pattern for mapping the landscape of Chinas communications industry; (2) the substantiation of the inner working mechanism of Chinas SOE system in the telecommunications sector; and (3) original first attempt in identifying different roles of telecom SOEs and the governing forces that affect them. The paper also offers extensive and cohesive insights on Chinas formal and informal institutional environment in general and for telecommunications in particular. Measurements developed in this study may serve as basis for future study. © 2011 Elsevier Ltd. All rights reserved.

Yao B.Z.,Beijing University of Posts and Telecommunications | Nie B.X.,University of California at Los Angeles | Liu Z.,Microsoft | Zhu S.-C.,University of California at Los Angeles
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2014

This paper presents animated pose templates (APTs) for detecting short-term, long-term, and contextual actions from cluttered scenes in videos. Each pose template consists of two components: 1) a shape template with deformable parts represented in an And-node whose appearances are represented by the Histogram of Oriented Gradient (HOG) features, and 2) a motion template specifying the motion of the parts by the Histogram of Optical-Flows (HOF) features. A shape template may have more than one motion template represented by an Or-node. Therefore, each action is defined as a mixture (Or-node) of pose templates in an And-Or tree structure. While this pose template is suitable for detecting short-term action snippets in two to five frames, we extend it in two ways: 1) For long-term actions, we animate the pose templates by adding temporal constraints in a Hidden Markov Model (HMM), and 2) for contextual actions, we treat contextual objects as additional parts of the pose templates and add constraints that encode spatial correlations between parts. To train the model, we manually annotate part locations on several keyframes of each video and cluster them into pose templates using EM. This leaves the unknown parameters for our learning algorithm in two groups: 1) latent variables for the unannotated frames including pose-IDs and part locations, 2) model parameters shared by all training samples such as weights for HOG and HOF features, canonical part locations of each pose, coefficients penalizing pose-transition and part-deformation. To learn these parameters, we introduce a semi-supervised structural SVM algorithm that iterates between two steps: 1) learning (updating) model parameters using labeled data by solving a structural SVM optimization, and 2) imputing missing variables (i.e., detecting actions on unlabeled frames) with parameters learned from the previous step and progressively accepting high-score frames as newly labeled examples. This algorithm belongs to a family of optimization methods known as the Concave-Convex Procedure (CCCP) that converge to a local optimal solution. The inference algorithm consists of two components: 1) Detecting top candidates for the pose templates, and 2) computing the sequence of pose templates. Both are done by dynamic programming or, more precisely, beam search. In experiments, we demonstrate that this method is capable of discovering salient poses of actions as well as interactions with contextual objects. We test our method on several public action data sets and a challenging outdoor contextual action data set collected by ourselves. The results show that our model achieves comparable or better performance compared to state-of-the-art methods. © 2014 IEEE.

Hu S.Q.,Beijing University of Posts and Telecommunications
Advanced Materials Research | Year: 2014

With the development of cloud-based data centers, cloud-based system has been widely used in many kinds of enterprises. Human resource management is an important issue in enterprise management.In this paper, we proposed a cloud based system for human resource management. Under the help of our design, the performance of the human resource management system can be improved apparently. In order to illustrate its superiority, we use some experiment to evaluate the proposed system. The experimental results indicated that the cloudy-based system would consume less memory and cpu resources while it has faster connection speed. © (2014) Trans Tech Publications, Switzerland.

Yang Y.-G.,Beijing University of Technology | Yang Y.-G.,Xidian University | Xia J.,Beijing University of Technology | Jia X.,Beijing University of Technology | Zhang H.,Beijing University of Posts and Telecommunications
Quantum Information Processing | Year: 2013

As an important branch of quantum cryptography, quantum private comparison (QPC) has recently received a lot of attention. In this paper we study the security of previous QPC protocols with a semi-honest third party (TP) from the viewpoint of secure multi-party computation and show that the assumption of a semi-honest TP is unreasonable. Without the unreasonable assumption of a semi-honest TP, one can easily find that the QPC protocol (Tseng et al. in Quantum Inf Process, 2011, doi: 10.1007/s11128-011-0251-0) has an obvious security flaw. Some suggestions about the design of QPC protocols are also given. © 2012 Springer Science+Business Media, LLC.

Xu L.,Columbia University | Zhang W.,Columbia University | Zhang W.,Beijing University of Posts and Telecommunications | Lira H.L.R.,Cornell University | And 2 more authors.
Optics Express | Year: 2011

We propose and experimentally demonstrate for the first time a hybrid optical packet and wavelength selective switching platform for highperformance data center networks. This architecture based on cascaded silicon microrings and semiconductor optical amplifiers (SOAs) supports wavelength reconfigurable packet and circuit switching, and is highly scalable, energy efficient and potentially integratable. By combining the wavelength-selective behavior of the microring and the broadband behavior of the SOA switch, we are able to achieve fast switching transitions, high extinction ratios, and low driving voltages, which are all requirements for future optical high-performance data center networks. Routing correctness and error-free operation (<10-12) are verified for both 10-Gb/s and 40-Gb/s packets and streaming data with format transparency. © 2011 Optical Society of America.

Xinyu Z.,Beijing University of Posts and Telecommunications
2011 IEEE 3rd International Conference on Communication Software and Networks, ICCSN 2011 | Year: 2011

As widespread pseudo-random sequences in spread spectrum communication system, M-sequence and Gold-sequence have their own characteristics. However, there are some differences between them. We will analysis these two different kinds of sequences in detail. And then we analyze and compare their correlation. At last, we analyze their typical applications in CDMA spread spectrum communication system. © 2011 IEEE.

Niu X.,Beijing University of Posts and Telecommunications
Metallurgical and Mining Industry | Year: 2015

To improve the predictive accuracy of network traffic, as for the training sample selection, this paper proposes a FCM-LSSVM for training sample selection. Firstly, fuzzy-means clustering algorithm is used to make cluster analysis of network filling data to eliminate the isolated sample points in it and to build training set of LSSVM, and then the training set is input to the LSSVM for learning. Furthermore, Artificial Bee Colony is used to optimize model parameters, and finally, network traffic forecasting model is established, and the simulation experiment is employed to test the performance of the model. Simulation results show that compared to other network traffic forecasting models, FCM-LSSVM not only improves the prediction accuracy of network traffic, and increases modeling speed, getting more desirable forecasted results of network traffic.

Xinchao Z.,Beijing University of Posts and Telecommunications
Applied Soft Computing Journal | Year: 2011

As we know, simulated annealing algorithm with large neighborhoods has greater probability of arriving at a global optimum than a small one has, if the other conditions, i.e., the initial configuration, initial temperature and temperature decreasing rate, are the same. However, the large neighborhood is not always beneficial, such as when the distance between the global optimum and the current solution is smaller than the step size. Therefore a simulated annealing algorithm with adaptive neighborhood is proposed in this paper. The adaptive non-uniform mutation operation borrowed from evolutionary algorithm is incorporated into simulated annealing for new solution generation. The neighborhood size reduces in probability with the progress of algorithm. It nearly covers the whole search space in the initial stage of algorithm in the sense of probability. The search engine only searches a very local neighborhood at the later stage of algorithm. Why to hybridize non-uniform mutation with simulated annealing is also analyzed and demonstrated. The numerical experiments show that the hybridization can greatly enhance the performance and the reliability of simulated annealing algorithm. Further experiments are made for benchmarks with expanding search domains. Satisfiable results are obtained again even if the variable bounds are enlarged to 1000 times. Theoretical analysis and simulation experiments illustrate the consistent excellent performance and the possible application of nonu-SA algorithm. © 2010 Elsevier B.V. All rights reserved.

Yutao T.,Beijing University of Posts and Telecommunications
Chinese Control Conference, CCC | Year: 2015

In this paper, we investigate a coordination problem of heterogeneous nonlinear multi-agent systems with prescribed behaviors described by another input-driven system. To overcome the difficulties along with time-varying communication topologies, both common Lyapunov function techniques and distributed observers are employed. Two control protocols are proposed regarding different cases. An example is given to verify their effectiveness. © 2015 Technical Committee on Control Theory, Chinese Association of Automation.

Chen L.,Tsinghua University | Chen L.,Chinese University of HongKong | Chen X.,Beijing University of Posts and Telecommunications | Zhang C.,Southern Utah University
Nonlinear Analysis: Real World Applications | Year: 2011

The bipolar EulerPoisson system in physics consists of the conservation laws for the electron and ion densities and their current densities, coupled with the Poisson equation for the electrostatic potential. The limit of vanishing ratio of the electron mass to the ion mass in the n-dimensional flat torus is proved in the case of well prepared initial data. The limiting system is composed of two separated equations, where the equation for electron is the incompressible Euler equation with damping, which means physically that the evolution for electrons and ions can be treated as separated motions in the small ratio case. © 2010 Elsevier Ltd. All rights reserved.

Xiang Z.,Beijing University of Posts and Telecommunications
Proceedings - 2014 7th International Symposium on Computational Intelligence and Design, ISCID 2014 | Year: 2015

In speaker diarization system, it's common to use bottom-up clustering method where the input data is first split in small pieces and then merged the most similar segments until reaching a stopping point. However, it's not easy to ensure that every selection merges the right pair, and these errors tend to deteriorate the post-merging results. In this paper, a fast cluster purification algorithm is introduced after the size of clusters reach to a pre-estimated number K, which is no less than the real number of speakers involved in the conversation, and try to remedy the errors by removing the inappropriate segments into the right cluster. An effective way to estimate the number of speakers is also introduced before the clustering stage. The experiment results show improvement in both the purity of cluster and the diarization error rate (DER) after using the purification algorithm. The purity improves 0.8% and DER reduces 1.14% in average. © 2014 IEEE.

Wang L.,Beijing University of Posts and Telecommunications
Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine | Year: 2010

Alpha-fetoprotein (AFP) computational secreted network construction and analysis of human hepatocellular carcinoma (HCC) is very useful to identify novel markers and potential targets for prognosis and therapy. By integration of gene regulatory network infer and the database for annotation, visualization, and integrated discovery, we identified and constructed significant molecule AFP secreted network from 25 no-tumor hepatitis/cirrhotic liver tissues and 25 HCC patients in the same GEO Dataset GSE10140-10141. Our result verified AFP secreted module in the upstream of no-tumor hepatitis/cirrhotic liver tissues (AMELY, LCN2, and REG3A activation; DKK1, SFRP4, and SPINK1 inhibition) and its downstream (PRSS1, REG3A, and TSHB activation; AMELY and DKK1 inhibition), and also in the upstream of HCC (LCN2, REG3A, and SFRP4 activation; AMELY and DKK1 inhibition) and its downstream (AMELY activation; DKK1, LCN2, PRSS1, SEMA3B, and SPINK1 inhibition). Importantly, we data-mined that AFP secreted cluster of HCC is involved in disease mutation (only in HCC terms) without cell surface receptor linked signal transduction, neuroactive ligand-receptor interaction, cell-cell signaling, and pancreas (only in no-tumor hepatitis/cirrhotic liver tissues terms), the condition which is vital to invasion of HCC. Our result demonstrated that common terms in both no-tumor hepatitis/cirrhotic liver tissues and HCC include secreted extracellular region, extracellular region part, extracellular space, signal peptide, signal, disulfide bond, glycosylation site N-linked (GlcNAc...), and glycoprotein, and these terms are less relative to invasion; therefore, we deduced the weaker AFP secreted network in HCC consistent with our number computation. We predicted AFP high expression localization within cells of HCC and without secretion to extracellular matrix. It would be necessary of AFP secreted function to decrease invasion of HCC.

Shi X.,Beijing University of Posts and Telecommunications | Lu Q.,Beihang University | Wang H.,Nanjing University of Science and Technology
International Journal of Bifurcation and Chaos | Year: 2012

In-phase burst synchronization, spatiotemporal order and rhythm dynamics of a complex neuronal network with electrical or chemically excitatory synapses are studied in this paper. A quantitative characteristic, the width factor, is introduced to describe the rhythm dynamics of an individual neuron, and the average width factor is used to characterize the rhythm dynamics of a neural network. The in-phase burst synchronization is studied in terms of the burst phase order parameter. We also study the effects of the coupling schemes, the intrinsic neuronal property and the network topology on the rhythm dynamics of the network. It is found that the neuronal network with electrical coupling is easier to realize the in-phase burst synchronization than that with the chemically excitatory coupling. The bursting type of short bursting neuronal networks is unchanged for different coupling schemes with the coupling strength increasing. Moreover, the short bursting type is robust both to the coupling strength and the coupling scheme. As for the network topology, more links can only change the bursting type of long bursting neurons, but short bursting neurons are robust to the link numbers. © 2012 World Scientific Publishing Company.

Li W.,Beihang University | Jia Y.,Beihang University | Du J.,Beijing University of Posts and Telecommunications | Zhang J.,Beihang University
IEEE Transactions on Vehicular Technology | Year: 2013

This paper studies the problem of simultaneous localization and tracking (SLAT) in non-line-of-sight (NLOS) environments. By combining a target state and a sensor node location into an augmented vector, a nonlinear system with two jumping parameters is formulated in which two independent Markov chains are used to describe the switching of the target maneuvers and the transition of LOS/NLOS, respectively. To derive the state estimate of the proposed jump Markov nonlinear system for each sensor node, an interacting multiple-model (IMM) approach and a cubature Kalman filter (CKF) are employed. As the number of mode-conditioned filters exponentially grows with the increases in the number of active sensor nodes in the centralized fusion, a distributed scheme is adopted to reduce the computational burden, and a covariance intersection (CI) method is used to fuse sensor-based target-state estimates. A numerical example is provided, involving tracking a maneuvering target by a set of sensors, and simulation results show that the proposed filter can track the target and can estimate the positions of active sensor nodes accurately. © 1967-2012 IEEE.

Li W.,Beihang University | Jia Y.,Beihang University | Du J.,Beijing University of Posts and Telecommunications | Zhang J.,Beihang University
Journal of the Franklin Institute | Year: 2013

This paper is concerned with the robust state estimation problem for a class of jump Markov linear systems (JMLSs) with missing measurements. Two independent Markov chains are used to describe the behavior of the system dynamics and the characteristic of missing measurements, respectively. A robust filtering algorithm is developed by applying the basic interacting multiple model (IMM) approach and the H∞ technique, which is different from the traditional Kalman filtering with minimum estimation error variance criterion. A maneuvering target tracking example is provided to demonstrate the effectiveness of the proposed algorithm. © 2013 The Franklin Institute.

Yu Y.,Beijing University of Posts and Telecommunications
IEEE Communications Letters | Year: 2015

An improved fixed-lag particle smoother in the mixture Kalman filter (MKF) framework is developed for the blind equalization in time-varying multiple-input multiple-output (MIMO) channels. The improved particle smoother utilizes the uniform proposal distribution (PD) and the optimal resampling to generate particles. Compared to the particle smoother with the posterior PD, the improved particle smoother can provide more accurate estimation results, while both smoothers have same computational complexity. Simulation results are provided to illustrate the performance of the methods. © 1997-2012 IEEE.

Yuan M.,Zhejiang Sci-Tech University | Liu A.,Zhejiang Sci-Tech University | Liu A.,Zhejiang University of Technology | Zhao M.,Zhejiang Sci-Tech University | And 4 more authors.
Sensors and Actuators, B: Chemical | Year: 2014

A bimetallic PdCu nanoparticle (NP) decorated three-dimensional graphene hydrogel (PdCu/GE) was developed by a simple one-step hydrothermal method. The PdCu/GE hybrids exhibited an interconnected microporous framework with PdCu NPs dispersed and encapsulated within the GE layers. The PdCu/GE hybrids showed significant electrocatalytic activity toward glucose oxidation due to the synergistic effect of PdCu NPs and GE sheets in the alkaline solution containing chloride ions, presenting a substantial increase in the oxidation current and decrease in the onset potential of oxidation compared to the monometallic modified GE hybrids. At an applied potential of -0.4 V, the PdCu/GE modified electrode with optimized bimetallic ratio presented quick respond to glucose oxidation with a wide linear range up to 18 mM and a reproducible sensitivity of 48 μA (mg mM)-1 in the presence of chloride ions. Furthermore, the PdCu/GE modified electrode exhibited high selectivity to glucose and resistance against poisoning by commonly interfering species such as dopamine, ascorbic acid, uric acid, acetamidophenol and some monosaccharides. The PdCu/GE hybrid hydrogels with 3D micropores were therefore promising for the future development of non-enzymatic amperometric glucose sensors with improved electrochemical performances. © 2013 Elsevier B.V.

Li W.,Beihang University | Jia Y.,Beihang University | Du J.,Beijing University of Posts and Telecommunications | Zhang J.,Beihang University
IET Control Theory and Applications | Year: 2013

This article studies the problem of distributed filtering for jump Markov linear systems in a not fully connected sensor network. A distributed consensus filter is developed by applying an improved interacting multiple model approach in which the mode-conditioned estimates are derived by the Kalman consensus filter and the mode probabilities are obtained in the sense of linear minimum variance. A numerical example is provided to demonstrate the effectiveness of the proposed algorithm for tracking a manoeuvring target in a sensor work with eight nodes. © The Institution of Engineering and Technology 2013.

Zhao C.,Beijing University of Posts and Telecommunications | Zhao C.,Inha University | Kwak K.,Inha University
IEEE Transactions on Vehicular Technology | Year: 2010

Conflict-free power allocation for secondary users (SUs) in cognitive networks is a challenging problem because the accessible spectrum of the SUs is shared with the primary users (PUs). The problem becomes particularly difficult when the objective is to achieve maximum network capacity considering the mutual interference between the PUs and the SUs. In this paper, we specify the case with a single SU and multiple PUs, where both the SU and the PUs are orthogonal frequency-division multiplexing (OFDM) modulated. The power allocation for the subcarriers of the SU is modeled into a constrained optimization problem, where the mutual interference between the SU and the PUs is comprehensively formulated as restrictions on the SU's transmission power. As a result, the proposed modeling scheme restrains the interference to the PUs, as well as maximizing the capacity of the SU. A novel iterative power-loading algorithm with low computational complexity is proposed to realize the power loading. On this basis, a suboptimal integral-bit-loading algorithm is further presented. In a simplified scenario, simulation results are exhibited to confirm the efficiency of the proposed power and bit-loading algorithms. Finally, the influence of the mutual interference on the SU's power/bit loading and the system capacity is illustrated. © 2006 IEEE.

Liu A.,Zhejiang Sci-Tech University | Liu A.,Zhejiang University | Ren Q.,Zhejiang Sci-Tech University | Xu T.,Zhejiang Sci-Tech University | And 2 more authors.
Sensors and Actuators, B: Chemical | Year: 2012

Gold nanostructures with controllable morphologies were synthesized by electrochemical deposition on phosphorus doped diamond-like carbon (DLC:P) film surfaces. The morphology of the as-synthesized gold nanostructures controlled by deposition potentials affected the electrocatalytic behavior of Au/DLC:P electrodes. The gold nanostructures obtained at -0.1 V showed a 3D flower-like morphology (consisting of staggered nanosheets), and exhibited higher electrocatalytic activity towards glucose electrooxidation at the potential below 0.1 V in alkaline media compared with other gold nanostructures (hemispherical and branched clusters) in terms of more unsaturated gold (2 2 0) and (3 1 1) crystal faces and monolayer oxide mediators on gold surfaces. The gold nanostructures with controllable morphologies were hence promising for the development of an electrocatalyst of non-enzymatic glucose sensor. © 2011 Elsevier B.V. All rights reserved.

Ngai C.-K.,Chinese University of Hong Kong | Yeung R.W.,Chinese University of Hong Kong | Zhang Z.,Chinese University of Hong Kong | Zhang Z.,Beijing University of Posts and Telecommunications
IEEE Transactions on Information Theory | Year: 2011

In this work, we extend the notion of generalized Hamming weight for classical linear block codes to linear network codes by introducing the network generalized Hamming weight (NGHW) for a given network with respect to a fixed linear network code. The basic properties of NGHW are studied. We further show that NGHW can be used as a tool to characterize the security performance of a linear network code on a wiretap network. We also introduce the notion of network maximum distance separable code (NMDS code) by extending the notion of Maximum Distance Separable code in classical algebraic coding theory. We prove that NMDS codes play an important role in minimizing the information that an eavesdropper can obtain from the network. © 2006 IEEE.

Zhuo X.,Beijing University of Posts and Telecommunications
2012 IEEE 6th International Conference on Systems Biology, ISB 2012 | Year: 2012

Mathematical models have been used to understand the factors that govern infectious disease progression in viral infections. Many models ignore the loss term of free virus particle when it enters the target cell. In this paper, we discuss a virus infection model with the loss term of free virus and the non-cytolytic loss of infected cells. Stable analysis of our model was given. If the basic reproduction number R 0 < 1, the infection-free equilibrium is globally asymptotically stable and the virus is cleared; if the basic reproduction number R 0 > 1, then the virus would persist in the host. © 2012 IEEE.

Zeng R.,Beijing University of Posts and Telecommunications
Advanced Materials Research | Year: 2014

Wireless Sensor Networks (WSNs) are used in many applications in military and commercial areas. These applications often include the monitoring of sensitive information such as enemy movement on the battlefield or the location of personnel in a building. However, due to the highly resource constrained in sensor nodes, traditional security strategies always can do few with attacks on WSNs. In this Paper, we proposes a study of attacks and security mechanisms in WSNs. First, we summarize the attacks to WSNs and the security requirements based on the TCP\IP networking model, then we present the security solutions to each attack. Along the way we highlight the advantages and disadvantages of various WSN solutions and further compare and evaluate these solutions. © (2014) Trans Tech Publications, Switzerland.

Chen H.,Beijing University of Posts and Telecommunications
Journal of Computers | Year: 2011

The author aims at studying the influence of consumer-generated comments of the shopping sites on consumer trust. The research divides consumer-generated comments into four types: service comments, product and price comments, self-display comments and after-action comments. With the survey result of 166 college students, the author finds that online shoppers' trust are influenced by consumer-generated comments of the shopping websites significantly. The data is analyzed by SPSS 15.0 and LISREL 8.8. The results show that product and price comments, the self-display comments, and after-sale action comments influence consumer trust to shopping sites remarkably. © 2011 ACADEMY PUBLISHER.

Hu S.Q.,Beijing University of Posts and Telecommunications
Advanced Materials Research | Year: 2014

Software security is facing enormous challenges with the rapid development of attacking technology. Obsolete software protection methods can no longer meet the needs of modern software security. In this paper, we proposed a software protection mechanism based on virtual machine which can compile the x86 assembly instructions into virtual instructions. The execution of instructions will be completed in the virtue machine so this mechanism can resist the attack of reverse analysis, meanwhile, the rights of software developers and intellectual property will be protected. furthermore, we design a random instruction generation algorithm to make the code of instructions haphazard, so that the protective ability of VM can be enhanced. We use some experiment to illustrate its superiority and the experimental results indicated that the protective effect of the proposed mechanism is excellent. © (2014) Trans Tech Publications, Switzerland.

Cao J.,Beijing University of Posts and Telecommunications | Gao H.,Harbin Engineering University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

In order to solve discrete optimization problem, this paper proposes a quantum-inspired bacterial swarming optimization (QBSO) algorithm based on bacterial foraging optimization (BFO). The proposed QBSO algorithm applies the quantum computing theory to bacterial foraging optimization, and thus has the advantages of both quantum computing theory and bacterial foraging optimization. Also, we use the swarming pattern of birds in block introduced in particle swarm optimization (PSO). Then we evaluate the efficiency of the proposed QBSO algorithm through four classical benchmark functions. Simulation results show that the designed algorithm is superior to some previous intelligence algorithms in both convergence rate and convergence accuracy. © 2012 Springer-Verlag.

Yang Z.,Ecole Polytechnique Federale de Lausanne | Yang Z.,Beijing University of Posts and Telecommunications | Soto M.A.,Ecole Polytechnique Federale de Lausanne | Thevenaz L.,Ecole Polytechnique Federale de Lausanne
Optics Express | Year: 2016

The robustness of bipolar pulse coding against pump depletion issues in Brillouin distributed fiber sensors is theoretically and experimentally investigated. The presented analysis points out that the effectiveness of bipolar coding in Brillouin sensing can be highly affected by the power unbalance between -1's and + 1's elements resulting from depletion and amplification of coded pump pulses. In order to increase robustness against those detrimental effects and to alleviate the probe power limitation imposed by pump depletion, a technique using a three-tone probe is proposed. Experimental results demonstrate that this method allows increasing the probe power by more than 12.5 dB when compared to the existing single-probe tone implementation. This huge power increment, together with the 13.5 dB signal-to-noise enhancement provided by 512-bit bipolar Golay codes, has led to low-uncertainty measurements (< 0.9 MHz) of the local Brillouin peak gain frequency over a real remoteness of 100 km, using a 200 km-long fiber-loop and 2 m spatial resolution. The method is evaluated with a record figure-of-merit of 380'000. ©2016 Optical Society of America.

Jian-Hui X.,Beijing University of Posts and Telecommunications
Proceedings of 2015 IEEE International Conference on Computer and Communications, ICCC 2015 | Year: 2015

A large number of Internet applications spawned by the IP based Internet have been rapidly eroding the traditional business of telecom operators in disruptive innovation business model. The traditional telecom operators have put forward the strategy of transformation, but the transformation is lack of theoretical analysis. By using Stackelberg economy analysis model, this paper deduced that it is not the optimal strategy for telecom operators to enter the Internet application. By using the strategy of Kaldor efficiency rather than Pareto efficiency, the operator provider should take transformation to build intelligent network to maximum the total efficiency. Furthermore, by contructing the intelligent network system, telecom operators should focus on the optimization of the transmission and control ability and large network computing, storage, dispatching ability. Finally the paper puts forward the suggestions of the mechanism to build intelligent pipeline. © 2015 IEEE.

Wu S.,Zhengzhou University | Wu S.,University of Chinese Academy of Sciences | Pu Q.,Tongji University | Wang S.,Beijing University of Posts and Telecommunications | He D.,Wuhan University
Information Sciences | Year: 2012

We revisit the communication-efficient three-party password authenticated key exchange protocol recently proposed by Chang et al. We show it is insecure against partition attacks, whereby the adversary can guess the correct password off-line. Thereafter we propose an enhanced protocol that can resist the attack described and yet is quite efficient. Furthermore, we prove its security in a widely accepted model. © 2012 Elsevier Inc. All rights reserved.

Zhou N.,Nanchang University | Zhou N.,Beijing University of Posts and Telecommunications | Zhang A.,Nanchang University | Zheng F.,Nanchang University | And 2 more authors.
Optics and Laser Technology | Year: 2014

The existing ways to encrypt images based on compressive sensing usually treat the whole measurement matrix as the key, which renders the key too large to distribute and memorize or store. To solve this problem, a new image compression-encryption hybrid algorithm is proposed to realize compression and encryption simultaneously, where the key is easily distributed, stored or memorized. The input image is divided into 4 blocks to compress and encrypt, then the pixels of the two adjacent blocks are exchanged randomly by random matrices. The measurement matrices in compressive sensing are constructed by utilizing the circulant matrices and controlling the original row vectors of the circulant matrices with logistic map. And the random matrices used in random pixel exchanging are bound with the measurement matrices. Simulation results verify the effectiveness, security of the proposed algorithm and the acceptable compression performance. © 2014 Elsevier Ltd.

Zhao G.,Beijing University of Posts and Telecommunications
International Journal of Security and its Applications | Year: 2015

Two-way quantum secure communication protocol and one-way quantum secure communication protocol based on single photon sequence and the XOR operation have been proposed, one-way communication can confuse the eavesdroppers and two-way communication only a single authentication and there is not visible to eavesdropping and delayed photon attack Trojan horse attack. The new agreement the use of single photon sequence and no regularity not only to achieve unconditional security, and semantics confuse eavesdroppers and has a high transmission efficiency, easy implementation, especially suitable for use in noisy channels. © 2015 SERSC.

Lu Z.,Beijing University of Posts and Telecommunications | Xie F.,Liaoning Normal University
Mathematical and Computer Modelling | Year: 2010

A generalized KP equation with variable coefficients, including the KP equation and the cylindrical KP equation as its special cases is investigated using a constructive algorithm and symbolic computation. Explicit bi-soliton-like solutions of the equation are obtained under certain constraints on the coefficient functions. For different coefficient functions, the solutions can model different types of bi-soliton-like waves. Some interesting bi-soliton-like waves are graphically revealed. © 2010 Elsevier Ltd.

Su Z.,Shanghai University | Xu Q.,Shanghai University | Zhu H.,Shanghai JiaoTong University | Wang Y.,Beijing University of Posts and Telecommunications
IEEE Network | Year: 2015

With the rapid development of mobile communication technologies, various kinds of content can be delivered among mobile users for content sharing. Due to the complexity of networks and particular features of mobile behaviors, to manage networks efficiently, SDMSNs are advocated where the control plane and data plane can work separately but cooperatively. In this article we outline how to deliver mobile content over SDMSNs. We first design the flow table based on the social features including social tie, mobility, and community. Then a novel social switch is introduced to deliver content among mobile users by using the proposed social degree and social stay time. In addition, the process of content delivery is presented according to different scenarios, and extensive experiments are given to prove the efficiency of this approach. © 2015 IEEE.

Li B.,Beijing University of Posts and Telecommunications
Journal of Networks | Year: 2013

According to the characteristics of human pulse wave signals, the acquisition system acquisition system with excellent performance is designed, 16 bit MCU MSP430 with ultralow power is used to record, process and transmit the collected pulse wave signals. In order to make the hardware part satisfy acquisition requirements of pulse wave, the paper focuses on discussing composition, operating principle, analysis method and performance parameter of analog circuit. The software part makes use of the design tools of Matlab graphical user interface (GUI) for designing pulse wave signal measurement system. The trial on intelligent fatigue test signal adopts relatively unique methods no matter in hardware circuit design or software algorithm process, which provides important and meaningful reference for objective and quantitative research on fatigue signal. © 2013 ACADEMY PUBLISHER.

Lei L.,Beijing Jiaotong University | Zhang Y.,Beijing University of Posts and Telecommunications | Shen X.S.,University of Waterloo | Lin C.,Tsinghua University | Zhong Z.,Beijing Jiaotong University
IEEE Transactions on Wireless Communications | Year: 2013

In this paper, we study the performance of Device-to-Device (D2D) communications with dynamic interference. In specific, we analyze the performance of frequency reuse among D2D links with dynamic data arrival setting. We first consider the arrival and departure processes of packets in a non-saturated buffer, which result in varying interference on a link based on the change of its backlogged state. The packet-level system behavior is then represented by a coupled processor queuing model, where the service rate varies with time due to both the fast fading and the dynamic interference effects. In order to analyze the queuing model, we formulate it as a Discrete Time Markov Chain (DTMC) and compute its steady-state distribution. Since the state space of the DTMC grows exponentially with the number of D2D links, we use the model decomposition and some iteration techniques in Stochastic Petri Nets (SPNs) to derive its approximate steady state solution, which is used to obtain the approximate performance metrics of the D2D communications in terms of average queue length, mean throughput, average packet delay and packet dropping probability of each link. Simulations are performed to verify the analytical results under different traffic loads and interference conditions. © 2013 IEEE.

A full-duplex link implementing alternative wired and wireless access for wavelength-division multiplexing passive optical network is proposed with the uniformed three-tone converged optical signal, which provides a wired or wireless downlink access signal alternatively and an uplink optical carrier. The uplink optical carrier reversed by the converged optical signal makes the hybrid optical node unit free from the optical source. The simulation results show that the full-duplex link with a 10-Gb/s 16-quadrature amplitude modulation (16-QAM) downstream and 5 Gb/s binary upstream can provide both wired access with a bit-error rate below 10-9 and radio-over-fiber-based wireless access with a bit-error rate below 10-7 over 40 km of fiber without an optical source and optical amplifier in the hybrid optical node unit. © 2014 Taylor and Francis Group, LLC.

Liu J.,Central South University | Lu P.-J.,Central South University | Liang S.,Central South University | Liu J.,Pacific Northwest National Laboratory | And 4 more authors.
Nano Energy | Year: 2015

Two-dimensional (2D) "graphene-like" inorganic materials, because of the short lithium ion diffusion path and unique 2D carrier pathways, become a new research focus of the lithium storages. Some "graphene-like" binary compounds, such as, MnO2, MoS2 and VO2 ultrathin nanosheets, have been synthesized by the peeling method, which also exhibit enhanced lithium storage performances. However, it still remains a great challenge to synthesize widely-used lithium-containing ternary oxides with "graphene-like" nanostructures, because the lithium-containing ternary oxides, unlike ternary layered double hydroxides (LDH), are very hard to be directly peeled. Herein, we successfully synthesized ultrathin Li3VO4 nanoribbons with a thickness of about 3nm by transformation from ultrathin V2O5·xH2O nanoribbons, moreover, we achieved the preparation of ultrathin Li3VO4 nanoribbon@graphene sandwich-like nanostructures (LVO/G) through the layer-by-layer assembly method. The unique sandwich-like nanostructures shows not only a high specific reversible capacitance (up to 452.5mAhg-1 after 200 cycles) but also an excellent cycling performance (with more than 299.2mAhg-1 of the capacity at 10C after 1000 cycles) as well as very high rate capability. Such template strategy, using "graphene-like" binary inorganic nanosheets as templates to synthesize lithium-containing ternary oxide nanosheets, may be extended to prepare other ternary oxides with "graphene-like" nanostructures. © 2015 Elsevier Ltd.

Hou W.,Northeastern University China | Guo L.,Northeastern University China | Guo L.,Beijing University of Posts and Telecommunications | Wei X.,University of California at Riverside | Gong X.,Northeastern University China
Computer Networks | Year: 2012

Previous studies on the power efficiency or port savings in IP over WDM networks have required explicit knowledge of the traffic between each network node pair and the resource assignment of each fiber link. However, it is difficult to estimate this information accurately in live networks, due to the inherent features of IP traffic, e.g., bursts, unpredictability, and variability. Furthermore, the granularity of the demands on an IP-level connection tends to be diverse, and the number of ports consumed in Optical Cross-Connects (OXCs) tends to grow due to the use of hybrid grooming (i.e., traffic grooming with an optical bypass) for power savings. Therefore, it is critical to achieve both power efficiency and port savings in realistic IP over WDM networks. In this paper, we investigate the problem of multi-granularity and robust grooming for power- and port-cost-efficient IP over WDM networks. First, a key parameter, the Multi-Granularity Power Ratio (MGPR), which is the sum of the different single-granularity power ratios, is proposed. Second, the MMPR (Minimizing Multi-granularity Power Ratio) method is used to compute the Traffic Distribution Vectors. Finally, we present the multi-granularity and robust grooming approach, called the Maximizing Hop First (MXHF) approach, where hybrid grooming is adopted to improve power efficiency and waveband merging is utilized to reduce the port cost. Simulation results demonstrate that the MXHF approach can achieve power efficiency and port savings comparing with state-of-the-art robust grooming methods. © 2012 Elsevier B.V. All rights reserved.

Jiang D.,Northeastern University China | Jiang D.,Beijing University of Posts and Telecommunications | Xu Z.,Northeastern University China | Chen Z.,Northeastern University China | And 2 more authors.
Computer Networks | Year: 2011

When 3G, WiFi, and WiMax technologies are successfully applied to access networks, current communication networks become more and more complex, more and more heterogeneous, and more difficult to manage. Moreover, network traffic exhibits the increasing diversities and concurrently shows many new characteristics. The real-time end-to-end demand urges network operators to learn and grasp traffic matrix covering their networks. However, unfortunately traffic matrix is significantly difficult directly to attain. Despite many studies made previously about traffic matrix estimation problem, it is a significant challenging to obtain its reliable and accurate solution. Here we propose a novel approach to solve this problem, based on joint time-frequency analysis in transform domain. Different from previous methods, we analyze the time-frequency characteristics about traffic matrix and build the time-frequency model describing it. Generally, traffic matrix can be divided into tendency terms and fluctuation terms. We find that traffic matrix in time-frequency domain owns the more obvious sparsity than in time domain. Obviously, its tendency terms and fluctuation terms also have the lower dimensions in time-frequency domain. This brings us into the field of compressive sensing that is a generic technique for data reconstruction. Additionally, we take into account updating time-frequency model presented with link loads to make our model adaptive. Finally, comparative analysis in two real backbone networks confirms that the accuracy, stability, and effectiveness of our approach. © 2011 Elsevier B.V. All rights reserved.

Lu X.,Beijing University of Posts and Telecommunications | Hui P.,Deutsche Telekom AG
Proceedings - 2010 IEEE International Conference on Networking, Architecture and Storage, NAS 2010 | Year: 2010

In Delay Tolerant Networks (DTN), as disconnections between nodes are frequent, establishing routing path from the source node to the destination node may not be possible. However, if a node transmits packets to all its encounters, its batteries will be used up quickly. Many researches have been done on routing and forwarding algorithms in DTN, but few of them have explicitly address the energy issue. In this paper, we propose n-epidemic routing protocol, an energy-efficient routing protocol for DTN. The n-epidemic routing protocol is based on the reasoning that in order to reach a large audiences with low number of transmissions, it is better to transmit only when the number of neighbors reaching a certain threshold. We compare the delivery performance of n-epidemic routing protocol with basic epidemic routing protocol using both analytical approach and empirical approach with real experimental dataset. The experiment shows that n-epidemic routing protocol can increase the delivery performance of basic epidemic-routing by 434% averagely. © 2010 IEEE.

Tian C.,Tongji University | Tian C.,Beijing University of Posts and Telecommunications | Yang B.,Ball State University
Future Generation Computer Systems | Year: 2011

Peer-to-peer (P2P) networking is widely used to exchange, contribute, or obtain files from any participating user. Building trust relationships between peers in a large-scale distributed P2P file-sharing system is a fundamental and challenging research topic. However, it is difficult to build a good trust relationship with the traditional mechanism. Recommendation based trust model from social relationship can be adopted to resolve the problem. But it faces the challenges of subjectivity, and experiential referral weighting. This paper presents R2Trusta robust Reputation and Risk evaluation based Trust management model. Our novel framework uses both reputation and risk to evaluate the trustworthiness of a peer and it is applicable for unstructured P2P networks. The model will evaluate peer trust values from direct interactions and peers referrals. R2Trust also distinguishes the credibility of peers. As a result, the aggregated trust value will filter out the noises and reflect more accurate trust values. The proposed R2Trust can also defense against several malicious attacks, such as simple malicious attacks, collusive attacks, and strategic attacks. Our experimental results show that, compared to the existing trust models, our model is cleanly a winner when security is the major concern of a system. © 2011 Elsevier B.V. All rights reserved.

Wang X.-Y.,Liaoning Normal University | Wang X.-Y.,Beijing University of Posts and Telecommunications | Wang T.,Liaoning Normal University | Bu J.,Liaoning Normal University
Pattern Recognition | Year: 2011

Image segmentation is an important tool in image processing and can serve as an efficient front end to sophisticated algorithms and thereby simplify subsequent processing. In this paper, we present a color image segmentation using pixel wise support vector machine (SVM) classification. Firstly, the pixel-level color feature and texture feature of the image, which is used as input of SVM model (classifier), are extracted via the local homogeneity model and Gabor filter. Then, the SVM model (classifier) is trained by using FCM with the extracted pixel-level features. Finally, the color image is segmented with the trained SVM model (classifier). This image segmentation not only can fully take advantage of the local information of color image, but also the ability of SVM classifier. Experimental evidence shows that the proposed method has a very effective segmentation results and computational behavior, and decreases the time and increases the quality of color image segmentation in comparison with the state-of-the-art segmentation methods recently proposed in the literature. © 2010 Elsevier Ltd. All rights reserved.

Ma J.,Beijing University of Posts and Telecommunications
Journal of Optical Communications and Networking | Year: 2011

A scheme to implement the full-duplex radio-over-fiber (RoF) link by quadrupling the frequency of the electrical RF carrier without a lightwave source at the remote base station (RBS) is proposed. Not only does the scheme reduce the complexity of the RBS and its frequency requirement for the devices, but the generated optical millimeter-wave (mm-wave) signal also has good transmission performance because both the fading effect and the bit walk-off effect caused by fiber dispersion are avoided. A 5 Gbit/s full duplex RoF simulation link with a 40GHz optical mm-wave signal is built. It shows that the eye diagrams of both the uplink and downlink signals remain open and clear even after the signals are transmitted over 60 km standard single-mode fibers. The simulation results agree well with our theoretical prediction. © 2011 Optical Society of America.

Huang X.,Beijing University of Posts and Telecommunications | Ma M.,Nanyang Technological University
Journal of Network and Computer Applications | Year: 2011

In this paper, a novel quality of service (QoS) prediction framework is proposed to accommodate different applications with various QoS requirements. The purpose of the proposed structure is to estimate, given the QoS requirements of different applications, the number of them can be satisfied according to the predefined QoS level and the number of them have to be rejected or accepted under lower level. Moreover, this structure is able to control the network behavior when the new application with certain QoS requirements requesting for the connection. The framework consists of four modules. QoS Requirements Monitoring detects the changes in the supplied QoS. QoS Prediction performs at real-time to estimate whether the new QoS can be adapted to the current QoS. QoS Violation is dedicated to detect the violation. And a module of QoS Estimation is used to make the decision whether the hopeless new traffic is refused or accepted with acceptable QoS requirements. Therefore, this structure is able to control network behavior when the surrounding environment changes. Numerical and simulation results obtained suggest that the proposed predictive scheme is a promising approach for real time QoS prediction. © 2011 Published by Elsevier Ltd.

Wang B.,North China University of Technology | Tang C.,Peking University | Qi Y.,Peking University | Qi Y.,Aisino Corporation Inc. | And 3 more authors.
IEEE Transactions on Information Theory | Year: 2012

Cyclic codes with two zeros and their dual codes as a practically and theoretically interesting class of linear codes have been studied for many years and find many applications. The determination of the weight distributions of such codes is an open problem. Generally, the weight distributions of cyclic codes are difficult to determine. Utilizing a class of elliptic curves, this paper determines the weight distributions of dual codes of q-ary cyclic codes with two zeros for a few more cases, where q is an odd prime power. © 1963-2012 IEEE.

Xia J.,Beijing University of Posts and Telecommunications
Telecommunications Policy | Year: 2016

The integration of "access" and "applications" into a single national program, as demonstrated in the Chinese case, once succeeded, may constitute a milestone in the arena of universal service policy and implementation. Despite scholarly consensus on the relevance of institutions, none has been found on a systemic examination of institutional variables in explaining the effectiveness of policy and implementation, let alone knowledge gap in a transitional context. Following historical institutionalism and case method, this and the companion paper bridge the gap by synthesizing a conceptual framework which integrates various institutional dimensions and policy elements underpinning the implementation of universal service initiatives. This paper provides a formal institutional perspective on the analysis and assessment, ex ante or ex post, of universal service policy and projects in China. The conceptual framework may serve as the basis for the analysis and assessment of China's rural informatization regime and projects. Meanwhile, the ecosystem model proposed in this paper has a potential of being extended to other countries. This study may collaterally further understanding of China's ongoing market reform from a nonmarket perspective. © 2015 Elsevier Ltd.

Li C.-G.,Beijing University of Posts and Telecommunications | Vidal R.,Johns Hopkins University
Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition | Year: 2015

Subspace clustering refers to the problem of segmenting data drawn from a union of subspaces. State of the art approaches for solving this problem follow a two-stage approach. In the first step, an affinity matrix is learned from the data using sparse or low-rank minimization techniques. In the second step, the segmentation is found by applying spectral clustering to this affinity. While this approach has led to state of the art results in many applications, it is sub-optimal because it does not exploit the fact that the affinity and the segmentation depend on each other. In this paper, we propose a unified optimization framework for learning both the affinity and the segmentation. Our framework is based on expressing each data point as a structured sparse linear combination of all other data points, where the structure is induced by a norm that depends on the unknown segmentation. We show that both the segmentation and the structured sparse representation can be found via a combination of an alternating direction method of multipliers with spectral clustering. Experiments on a synthetic data set, the Hopkins 155 motion segmentation database, and the Extended Yale B data set demonstrate the effectiveness of our approach. © 2015 IEEE.

Yan H.,Beijing University of Posts and Telecommunications
Neurocomputing | Year: 2016

In this paper, we propose an activity-based person recognition approach based on discriminative sparse projections (DSPs) and ensemble metric learning. Unlike gait recognition where only the walking activity is utilized for human identification, we aim to recognize people from more types of activities such as eating, drinking, running, and so on. Our motivation is inspired by the fact that people do not always walk in person identification systems and gait recognition could fail to work in this scenario. Given each video clip, we first extract the binary human body mask in each frame by using background substraction. Then, we propose a DSP method to project these body masks into a low-dimensional subspace and cluster them into a number of clusters simultaneously. Subsequently, each video clip is pooled as a histogram feature for activity representation. Lastly, we propose an orthogonal ensemble metric learning (OEML) method to learn a distance metric to exploit more discriminative information for recognition. Experimental results on five benchmark activity databases are presented to show the efficacy of our proposed approach. Moreover, we apply our approach to gait recognition and also achieve competitive results with the state-of-the-art methods on the widely used CASIA-B gait dataset. © 2016 Elsevier B.V.

Chen H.,Beijing University of Posts and Telecommunications
Journal of Software | Year: 2011

This paper did a survey on 162 college students, with an aim to find out the role of consumers' personality in their trust in the website as far as the online word-of-mouth is concerned. All the data collected are analyzed by SPSS 15.0 and LISREL. It shows that there is a significant difference between the introverted consumers and the extroverted consumers viewing their attitude towards online word-of-mouth. When the online word-of-mouth is affecting the consumers' trust in shopping websites, the introverted and extroverted influence exist difference. © 2011 ACADEMY PUBLISHER.

Zheng Z.,Beijing University of Posts and Telecommunications | Ma H.,Microsoft | Lyu M.R.,Chinese University of Hong Kong | King I.,Chinese University of Hong Kong
IEEE Transactions on Services Computing | Year: 2013

With the increasing presence and adoption of web services on the World Wide Web, the demand of efficient web service quality evaluation approaches is becoming unprecedentedly strong. To avoid the expensive and time-consuming web service invocations, this paper proposes a collaborative quality-of-service (QoS) prediction approach for web services by taking advantages of the past web service usage experiences of service users. We first apply the concept of user-collaboration for the web service QoS information sharing. Then, based on the collected QoS data, a neighborhood-integrated approach is designed for personalized web service QoS value prediction. To validate our approach, large-scale real-world experiments are conducted, which include 1,974,675 web service invocations from 339 service users on 5,825 real-world web services. The comprehensive experimental studies show that our proposed approach achieves higher prediction accuracy than other approaches. The public release of our web service QoS data set provides valuable real-world data for future research. © 2008-2012 IEEE.

Wang X.,University of Science and Technology Beijing | Zhou X.,University of Science and Technology Beijing | Song J.,Beijing University of Posts and Telecommunications
Journal of Networks | Year: 2012

In the future, it is important to construct infrastructure on the surface of deep space planets, and then networking can be achieved to support both the communication between surface network nodes and planet satellite access. And because multiple access is an important technique in deep space communication, a scene of deep space exploration was proposed based on multiple access, which include planet surface network and satellite access network. Then hypergraph theory was used to model the network, thus provide a new way to improve the network connectivity, save frequency spectrum resource and reduce mutual interference, and also how to construct a hyper-edge was described. According to the network model, a 7-layer network architecture was introduced. © 2012 ACADEMY PUBLISHER.

Chen H.,Beijing University of Posts and Telecommunications
Journal of Networks | Year: 2012

The author aims at studying the influence of comments and recommendation on online shopping behaviours. With 285 study subjects, the author used experimental research design to study comments and recommendation system on online shopping experience, online shopping satisfaction, online shopping intention and items chosen. The data is analyzed by SPSS 15.0 and LISREL 8.8. The results show that comments and recommendation influence online shopping experience, online shopping satisfaction and online shopping intention directly. Online shopping experience and online shopping satisfaction influence online shopping intention significantly. There is remarkable positive relation between online shopping intention and items chosen. © 2012 ACADEMY PUBLISHER.

Tang Y.,Beijing University of Posts and Telecommunications
Journal of Systems Science and Complexity | Year: 2016

This paper considers a robust consensus tracking problem of heterogeneous multi-agent systems with time-varying interconnection topologies. Based on common Lyapunov function and internal model techniques, both state and output feedback control laws are derived to solve this problem. The proposed design is robust by admitting some parameter uncertainties in the multi-agent system. © 2016 Institute of Systems Science, Academy of Mathematics and Systems Science, CAS and Springer-Verlag Berlin Heidelberg

Tang Y.,Beijing University of Posts and Telecommunications
Kybernetika | Year: 2015

In this paper, we consider an output consensus problem for a general class of nonlinear multiagent systems without a prior knowledge of the agents' control directions. Two distributed Nussbaum-type control laws are proposed to solve the leaderless and leader-following adaptive consensus for heterogeneous multiple agents. Examples and simulations are given to verify their effectiveness.

Yu J.-L.,Fu Jen Catholic University | Zhang B.,Beijing University of Posts and Telecommunications | Chen P.-T.,Fu Jen Catholic University
Signal Processing | Year: 2014

In this paper, the blind subspace channel estimation using the block matrix scheme is proposed for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. Based on the Toeplitz structure, the block matrix scheme collects a group of the received OFDM symbols into a vector, and then partitions it into a set of equivalent symbols. The number of equivalent symbols is about N times of OFDM symbols, where N is the size of FFT operation. With those equivalent symbols, the proposed blind subspace channel estimation can converge within a small amount of OFDM symbols. The identifiability of the proposed channel estimation is examined that the channel matrix is determined up to an ambiguity matrix. Besides, the semi-blind channel estimation is also investigated by combining few pilot sequences with the subspace method. Simulation results show that the proposed channel estimators perform very well even in a time-varying scenario. Especially the semi-blind methods achieve almost the same BERs as those by true channels. © 2013 Elsevier B.V.

Su D.,Beijing University of Posts and Telecommunications
Advanced Materials Research | Year: 2014

Sensor technology is the key technology in industrial application and scientific research. With the progress of microelectronics technology, computer technology and communication technology, determining how to connect various sensors and various networks freely becomes a new problem in the field of sensor application research. In this paper, first I introduced several important modules that IEEE 1451 standard has defined, then I analyzed concepts and models of intelligence sensor interface in IEEE 1451. Finally I build a model which is more suitable to wireless sensor network. © (2014) Trans Tech Publications, Switzerland.

Dai J.,Beijing University of Posts and Telecommunications
Proceedings - 2014 IEEE Workshop on Advanced Research and Technology in Industry Applications, WARTIA 2014 | Year: 2014

In this paper, we design a medical assistance system, which uses a data mining algorithm named improved genetic algorithm (IGA) to extract the proper behavior model according to the target database of the hospital, and develop the clinical pathways based on the behavior model. The quality of the behavior model can be evaluated by the application of the clinical pathways in the clinical diagnosis and treatment activities. To verify the performance of the algorithm, we compared the recall ratio and precision ratio of our algorithm with that of two typical algorithms named Genetic algorithm (GA) and Apriori in the simulation. The result shows that the performance of the IGA is better than the other two algorithms. © 2014 IEEE.

Xie G.,Peking University | Wang F.,Beijing University of Posts and Telecommunications | Dang A.,Peking University | Guo H.,Peking University
IEEE Photonics Technology Letters | Year: 2011

In this letter, a novel polarization-multiplexing system for free-space optical links is proposed. Data is specially designed at the transmitter while received by coupling two lights in different states of polarization (SOP) after polarization rotation at the receiver. Based on this design, the closed form expression for bit-error-rate (BER) performance of the system is given. Our results indicate that polarization control error has no obvious influence on the system performance when it is less than 10°. Performance of our system is superior to the traditional binary phase-shift keying (BPSK) scheme on overcoming phase fluctuation. © 2011 IEEE.

Liang L.-M.,National University of Defense Technology | Sun S.-H.,National University of Defense Technology | Ma H.-Q.,Beijing University of Posts and Telecommunications | Han J.-J.,National University of Defense Technology | Li C.-Z.,National University of Defense Technology
Optics Letters | Year: 2010

A robust two-way quantum key distribution system based on phase encoding is demonstrated in 50 km and 100 km commercial communication fiber. The system can automatically compensate for birefringence effects and remain stable over 23 h. A low quantum bit error rate and high visibility are obtained. Furthermore, the storage fiber is unnecessary and train of pulses is only needed in the test with 100 km fiber. © 2010 Optical Society of America.

Pei Y.,Beijing University of Posts and Telecommunications
Communications in Computer and Information Science | Year: 2012

In wireless ad hoc networks, location service is used to confirm geographical position and data information of a specific node for efficient routing. However, since in some specific circumstances ad hoc network localization cannot just rely on global positioning system (GPS), self-localization algorithm is a focus during wireless ad hoc research process and supplies solution for the problem. This paper integrates some existing prevalent self-localization algorithms and introduces some representative algorithms, then evaluates the algorithms and makes a comparison, at last educes a conclusion. © 2012 Springer-Verlag Berlin Heidelberg.

Zhou Y.,Beijing University of Posts and Telecommunications
Advanced Materials Research | Year: 2014

With the technology improvement of computer communication and multimedia coding, real time communication such as audio and video is introduced to networks and become a dominant way of communication. In the control of network, the optimization problem of the network controller based on network Quality of service (QoS) is a very important problem in the research of network control. Considering the influence of network quality-of service(QoS)on the control performance, a system model combining the network parameters and the control parameters is established for networked control systems(NCSs). Based on this, the condition dependent on the network parameters and control parameters is presented for the existence of guaranteed cost controllers. LMI). Within the scope of QoS perturbation, the designed controller can not only make the system as hypnotically stable but also guarantee that the system performance index is not greater than the upper bound. © (2014) Trans Tech Publications, Switzerland.

Gao G.,Beijing University of Posts and Telecommunications | Gao G.,University of Melbourne | Chen X.,University of Melbourne | Shieh W.,University of Melbourne
Journal of Lightwave Technology | Year: 2012

Closed-form expressions for nonlinear transmission performance of coherent optical OFDM systems (CO-OFDM) with frequency guard band are derived. The analytical expressions have been substantiated by numerical simulations using split-step method for various frequency spacings and fiber dispersion maps. The analytical solution shows good estimation accuracy, and the average absolute difference of Q factor between analytical results and numerical simulations are below 0.3 dB for the three typical systems simulated. Using this expression, the dependence of system performance for CO-OFDM on the frequency guard band spacing and fiber dispersion is also investigated analytically to provide insights for system design. © 1983-2012 IEEE.

Li A.,University of Melbourne | Al Amin A.,University of Melbourne | Chen X.,University of Melbourne | Chen S.,University of Melbourne | And 3 more authors.
Journal of Lightwave Technology | Year: 2012

We demonstrate the use of mechanical grating based mode converters to achieve two forms of dual-spatial-mode transmission: LP 01 and LP 11, and dual LP 11 modes. High modal extinction ratio (> 20 dB) is shown for the mode converter within a 10-nm wavelength range. We first present 107-Gb/s coherent optical OFDM (CO-OFDM) transmission over a 4.5-km two-mode fiber using LP 01 and LP 11 modes where the mode separation is performed optically. We then show 58.8-Gb/s CO-OFDM transmission using dual LP 11 modes where the mode separation is achieved via 4 × 4 electronic MIMO processing. © 2006 IEEE.

Schwartz S.,University of Waterloo | Liu C.,Beijing University of Posts and Telecommunications | Wong A.,University of Waterloo | Clausi D.A.,University of Waterloo | And 2 more authors.
Optics Express | Year: 2013

High quality, large size volumetric imaging of biological tissue with optical coherence tomography (OCT) requires large number and high density of scans, which results in large data acquisition volume. This may lead to corruption of the data with motion artifacts related to natural motion of biological tissue, and could potentially cause conflicts with the maximum permissible exposure of biological tissue to optical radiation. Therefore, OCT can benefit greatly from different approaches to sparse or compressive sampling of the data where the signal is recovered from its sub-Nyquist measurements. In this paper, a new energy-guided compressive sensing approach is proposed for improving the quality of images acquired with Fourier domain OCT (FD-OCT) and reconstructed from sparse data sets. The proposed algorithm learns an optimized sampling probability density function based on the energy distribution of the training data set, which is then used for sparse sampling instead of the commonly used uniformly random sampling. It was demonstrated that the proposed energy-guided learning approach to compressive FD-OCT of retina images requires 45% fewer samples in comparison with the conventional uniform compressive sensing (CS) approach while achieving similar reconstruction performance. This novel approach to sparse sampling has the potential to significantly reduce data acquisition while maintaining image quality. © 2013 Optical Society of America.

Song Z.,Beijing University of Posts and Telecommunications
Frontiers of Electrical and Electronic Engineering in China | Year: 2010

A novel adaptive cooperative medium access control (MAC) protocol, which is completely backward compatible with the legacy IEEE 802. 11 distributed coordination function (DCF), is proposed in this paper. To adapt to dynamic channel variation and network topology, the sender adaptively selects transmission scheme based on the instantaneous channel measurements. Analytical and simulation results show that the proposed protocol outperforms the existing one in terms of throughput, delay, energy and mobility. © 2010 Higher Education Press and Springer-Verlag Berlin Heidelberg.

Liu H.-L.,Chongqing University of Posts and Telecommunications | Zhang B.,Beijing University of Posts and Telecommunications | Shi S.-L.,Chongqing University of Posts and Telecommunications
Journal of Lightwave Technology | Year: 2012

Wavelength conversion is an efficient way to improve the optical packet blocking performance for all-optical packet switching networks. The synchronous OPS node architecture, with a hybrid shared wavelength conversion (HSWC) scheme based on shared per output fiber and shared per node wavelength conversion, is put forward to reduce the packet loss probability in this paper. A heuristics is developed into assigning the wavelength channels for packets in the proposed optical nodes. The limited range wavelength converters first available (LFA) algorithm and parametric wavelength converters first available (PFA) algorithm are used to schedule contending optical packets to available wavelength channels. Simulation results show that the hybrid shared wavelength conversion scheme has significant performance improvement in terms of packet loss probability. And the utilization of wavelength converter is greatly improved for OPS node with hybrid shared wavelength conversion scheme. Furthermore, the PFA scheduling algorithm compared with LFA algorithm is validated to improve the wavelength assignment efficiency and reduce the required total wavelength converters for OPS nodes. © 2006 IEEE.

Zhang W.,Beijing University of Posts and Telecommunications | Zhang W.,Columbia University | Wang H.,Columbia University | Bergman K.,Columbia University
Journal of Lightwave Technology | Year: 2012

The communication requirements imposed by the unabated growth in both the size and computational density of modern data centers will soon outpace the fundamental capabilities of conventional electronic interconnection networks. Optical interconnects represent a potentially disruptive technology that can simultaneously satisfy the throughput, latency, and energy demands of these next-generation systems. In this paper, we propose an end-to-end photonic networking platform for future optically-interconnected data center networks. A reconfigurable hybrid photonic network building block and a protocol-agnostic optical network interface comprise the key elements of our proposed system. A modular optical switch fabric prototyping platform is designed and implemented to support a wide variety of potential photonic technologies. We successfully demonstrate nanosecond-scale optical packet-switching at 1-Tb/s per port (40-Gb/s ×25λs) through our prototype, configured as a 4×4 switch, and confirm error-free transmission across all wavelengths. In order to flexibly allocate appropriate bandwidth for heterogeneous applications, we further implement and evaluate a novel wavelength-reconfigurable optical packet-and circuit-switch by utilizing our optical switch platform. Finally, we detail our implementation of an optical network interface card (O-NIC) designed to bridge the gap between the well-established protocol layers utilized in current networks and the physical layer of the proposed photonic networks and demonstrate its functionality by the streaming of high-definition video through the end-to-end optical network. © 2012 IEEE.

Taghia J.,KTH Royal Institute of Technology | Ma Z.,Beijing University of Posts and Telecommunications | Leijon A.,KTH Royal Institute of Technology
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2014

This paper addresses the Bayesian estimation of the von-Mises Fisher (vMF) mixture model with variational inference (VI). The learning task in VI consists of optimization of the variational posterior distribution. However, the exact solution by VI does not lead to an analytically tractable solution due to the evaluation of intractable moments involving functional forms of the Bessel function in their arguments. To derive a closed-form solution, we further lower bound the evidence lower bound where the bound is tight at one point in the parameter distribution. While having the value of the bound guaranteed to increase during maximization, we derive an analytically tractable approximation to the posterior distribution which has the same functional form as the assigned prior distribution. The proposed algorithm requires no iterative numerical calculation in the re-estimation procedure, and it can potentially determine the model complexity and avoid the over-fitting problem associated with conventional approaches based on the expectation maximization. Moreover, we derive an analytically tractable approximation to the predictive density of the Bayesian mixture model of vMF distributions. The performance of the proposed approach is verified by experiments with both synthetic and real data. © 1979-2012 IEEE.

Yu Y.,Beijing University of Posts and Telecommunications
Signal Processing | Year: 2013

This paper develops a state estimation method for conditionally linear dynamic systems in unknown non-Gaussian noises, which is a combination of the H∞ filter and the cost-reference particle filter (PF). The proposed method has similar algorithmic structure as the mixture Kalman filter (MKF), which is a combination of the Kalman filter and the standard PF for conditionally linear dynamic Gaussian systems. The MKF requires the knowledge of the noise distributions and the noises are Gaussian or conditional Gaussian with known parameters in the model, which might not hold in many practical applications, while the proposed method does not require the knowledge of the noise distributions and the noises can be non-Gaussian, so it is more flexible and has less limitation in applications. Two applications of the proposed method in telecommunications, as well as the computer simulation results, are provided to illustrate the performance of the proposed method. © 2012 Elsevier B.V.

Wang Z.,Beijing University of Posts and Telecommunications
Proceedings - 2011 International Conference on Computational and Information Sciences, ICCIS 2011 | Year: 2011

Cloud Computing has been regarded as evolutionary paradigm recently. It has much strength, such as large storage, ubiquitous network access, cost effective and so on. However it also faces security and privacy concerns. In this paper, we discussed several major security and privacy issues. And we also proposed four effective methods to handle such issues. According to the features of issues, we investigated the feasible solutions and finally found four methods. Such methods can be applied to the generalized Cloud Computing. This paper is original that we consider the characteristics of Cloud Computing adequately, so the methods are well functioned and can be developed further to solve other problems. © 2011 IEEE.

Xia J.,Beijing University of Posts and Telecommunications
Telecommunications Policy | Year: 2015

Our companion paper developed an institutional conceptual framework for the analysis and assessment of China's rural informatization regime and projects. Following the conceptual work and based on the case study of specific projects, this paper documents the institutional idiosyncrasies and identifies institutional variables affecting implementation effectiveness in China. If is found that China has fared well in some projects (usually at the construction or technical level) while encountered difficulties in some others (at semantic, service, and even higher levels), due to variance in the enforceability of differing institutional arrangements. China has arguably succeeded, at best, in the supply-side ("access" level) of the rural informatization ecosystem; this is partly because that the Chinese model has emphasized primarily on the formal side of institutions but considerably less so on the informal side. Accordingly, factors contributing to implementation success have, path-dependently, highlighted the functioning of regulative institutions but considerably less so of the normative-cognitive institutions. Policy implications are offered which call for a shift to the demand-side of the rural informatization ecosystem. © 2015 Elsevier Ltd.

Cheung K.T.K.,University of Southampton | Yang S.,University of Southampton | Yang S.,Beijing University of Posts and Telecommunications | Hanzo L.,University of Southampton
IEEE Transactions on Communications | Year: 2013

In this paper, the joint power and subcarrier allocation problem is solved in the context of maximizing the energy-efficiency (EE) of a multi-user, multi-relay orthogonal frequency division multiple access (OFDMA) cellular network, where the objective function is formulated as the ratio of the spectral-efficiency (SE) over the total power dissipation. It is proven that the fractional programming problem considered is quasi-concave so that Dinkelbach's method may be employed for finding the optimal solution at a low complexity. This method solves the above-mentioned master problem by solving a series of parameterized concave secondary problems. These secondary problems are solved using a dual decomposition approach, where each secondary problem is further decomposed into a number of similar subproblems. The impact of various system parameters on the attainable EE and SE of the system employing both EE maximization (EEM) and SE maximization (SEM) algorithms is characterized. In particular, it is observed that increasing the number of relays for a range of cell sizes, although marginally increases the attainable SE, reduces the EE significantly. It is noted that the highest SE and EE are achieved, when the relays are placed closer to the BS to take advantage of the resultant line-of-sight link. Furthermore, increasing both the number of available subcarriers and the number of active user equipment (UE) increases both the EE and the total SE of the system as a benefit of the increased frequency and multi-user diversity, respectively. Finally, it is demonstrated that as expected, increasing the available power tends to improve the SE, when using the SEM algorithm. By contrast, given a sufficiently high available power, the EEM algorithm attains the maximum achievable EE and a suboptimal SE. © 1972-2012 IEEE.

Chen W.,Beijing University of Posts and Telecommunications
Proceedings - 2015 International Conference on Industrial Informatics - Computing Technology, Intelligent Technology, Industrial Information Integration, ICIICII 2015 | Year: 2015

The Ebola virus can cause a severe disease, it is a fatal infectious diseases without treatment and popular in western Africa like Guinea, Sierra Leone and Liberia. Now we believe that Ebola virus first spread through the contact with infected animal blood, secretions or organ, and then diffuse from person to person. The mortality is 50% on average. There is no licensed Ebola vaccine, so actively participate into control these epidemic diseases is very important. This paper establishes a mathematical model about Ebola virus and analysis data to predict the spread. © 2015 IEEE.

Dong K.,Beijing University of Posts and Telecommunications
Guangxue Xuebao/Acta Optica Sinica | Year: 2016

The inversion-symmetry breaking Rabi model under ultra-strong coupling condition is studied with the adiabatic approximation method. The analytical expressions of the eigenfunctions and the eigenvalues are obtained, and the influence of the inversion-symmetry breaking on them is also studied. The dynamical behavior of the system, with initial status of Fock state and coherent state for the quantum harmonic oscillator, is discussed. The collapse and revival phenomena have been put particular attentions. The results show that the inversion-symmetry breaking changes the time and height of collapse and revival. © 2016, Chinese Lasers Press. All right reserved.

Du F.F.,Beijing Normal University | Deng F.G.,Beijing Normal University | Deng F.G.,Beijing University of Posts and Telecommunications
Science China: Physics, Mechanics and Astronomy | Year: 2015

We present two nonlocal entanglement concentration protocols (ECPs) to distill a subset of N-photon systems in a Greenberger-Horne-Zeilinger (GHZ) state or a W state from a set of photon systems in a partially entangled GHZ-like pure state or a less-entangled W-like state with known parameter, respectively. Our ECPs have some advantages. First, our ECPs work in a heralded way with linear-optical elements only, without the postselection based on nonlinear optics, far different from the previous ECPs. Second, they require only a copy of the less-entangled photon system in each round of the entanglement concentration process, not two copies, which decreases the difficulty of their implementation in experiment largely. Third, our ECPs avoid checking the photon number in the output modes of linear-optical elements with the sophisticated single-photon detectors. Moreover, all parties can operate the process for concentration simultaneously and independently, which leads to flexible operations and improves the performance greatly in experiment. These advantages make our ECPs useful in practical applications in long-distance quantum communication network. © 2015, Science China Press and Springer-Verlag Berlin Heidelberg.

Li M.,University of Arizona | Li M.,Beijing University of Posts and Telecommunications | Cvijetic M.,University of Arizona
Applied Optics | Year: 2015

We evaluate the performance of the coherent free space optics (FSO) employing quadrature array phase-shift keying (QPSK) modulation over the maritime atmosphere with atmospheric turbulence compensated by use of adaptive optics (AO). We have established a comprehensive FSO channel model for maritime conditions and also made a comprehensive comparison of performance between the maritime and terrestrial atmospheric links. The FSO links are modeled based on the intensity attenuation resulting from scattering and absorption effects, the log-amplitude fluctuations, and the phase distortions induced by turbulence. The obtained results show that the FSO system performance measured by the bit-error-rate (BER) can be significantly improved when the optimization of the AO system is achieved. Also, we find that the higher BER is observed in the maritime FSO channel with atmospheric turbulence, as compared to the terrestrial FSO systems if they experience the same turbulence strength. © 2015 Optical Society of America.

Qin W.,Beijing Institute of Technology | Wang C.,Beijing University of Posts and Telecommunications | Zhang X.,Beijing Institute of Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

We propose and analyze a robust quantum-state transfer protocol by the use of a combination of coherent quantum coupling and decoherence-free subspaces in a coupled quantum spin chain. Under decoherence, an arbitrary unknown quantum state embedded in a decoherence-free subspace can be perfectly transferred through a noisy channel being weakly coupled to two end registers. The method protects quantum information from both the channel noise and the environmental decoherence. A special case of utilizing two physical qubits to encode one logical qubit is considered as an example and the robustness is confirmed by numerical performances. © 2015 American Physical Society.

Wang H.,Shanghai JiaoTong University | Cao Z.,Shanghai JiaoTong University | Wang L.,Beijing University of Posts and Telecommunications
Information Sciences | Year: 2010

In a proxy re-encryption scheme, a semi-trusted proxy is given special power that allows it to transform a ciphertext for Alice into a ciphertext for Bob without learning any information about the messages encrypted under either key. When a proxy re-encryption scheme is constructed in an identity-based setting, it means that a proxy converts a ciphertext encrypted under Alice's identity into a ciphertext under Bob's. Proxy re-encryption has become more and more popular these years due to the fact that it has many practical applications. In this paper, we present an IND-CCA2 secure identity-based proxy re-encryption scheme which has several useful properties, including, multi-use, unidirectionality, etc. Finding a unidirectional, multi-use, and CCA2-secure proxy re-encryption scheme is presented as an open problem by Green et al. Fortunately, our identity-based proxy re-encryption scheme is a solution to this problem. As a middleware for fulfilling our main goal, we also propose a new construction of identity-based encryption using random padding techniques. The security of our schemes is based on the standard decisional bilinear Diffie-Hellman assumption in the random oracle model. © 2010 Elsevier Inc. All rights reserved.

Ai X.,Beijing University of Posts and Telecommunications
2014 IEEE 7th Joint International Information Technology and Artificial Intelligence Conference, ITAIC 2014 | Year: 2014

In this paper we study the technology transactions as a complex network, with 40531 contracting parties as the nodes and 76303 contractual relations as the edges. After exploring its topological properties, we observe that this network is characterized by two remarkable features which are already observed in numerous real-world and artificial networks. One is the small-world property, with the small-world index of 606.106, and the other is its scale-free distribution, with the degree exponent of 2.093. We also observe that this network exhibits some features that are not necessarily shared by other networks, such as the anti-correlation between clustering coefficients and degrees. Our work extends the network analysis to the domain of technology exchange and provides a novel approach to study technology exchange systems. © 2014 IEEE.

Zhou T.,University of Maryland University College | Zhou T.,Beijing University of Posts and Telecommunications | Chen Y.,University of Maryland University College | Liu K.J.R.,University of Maryland University College
IEEE Transactions on Wireless Communications | Year: 2014

This paper considers the cooperative optimization of mutual information in the MIMO Gaussian interference channel in a fully distributed manner via game theory. Null shaping constraints are enforced in the design of transmit covariance matrices to enable interference mitigation among links. The transmit covariance matrices leading to the Nash Equilibrium (NE) are derived, and the existence and uniqueness of the NE is analyzed. The formation of the cooperative sets, that represent the cooperation relationship among links, is considered as coalition games and network formation games. We prove that the proposed coalition formation (CF) and coalition graph formation (CGF) algorithms are Nash-stable, and the proposed network formation (NF) algorithm converges to a Nash Equilibrium. Simulation results show that the proposed CF and CGF algorithms have significant advantages when the antennas at the transmitters is large, and the proposed NF algorithm enhances the sum rate of the system apparently even at low signal-to-noise ratio region and/or with small number of transmit antennas. © 2002-2012 IEEE.

Zhao Y.,Beijing University of Posts and Telecommunications
Proceedings - 2013 International Conference on Computational and Information Sciences, ICCIS 2013 | Year: 2013

Web data mining is a key tool for e-commerce in such an age of Internet. Due to previous studies, there is no such a mining technology superior to others. Therefore, this paper can give a simplified comprehension of web data mining and indicate the improvement direction of each kind of mining algorithm based on their existing defects. This paper first introduces the main process of data mining, including collect data, preprocess data, store the data, apply data mining technologies and evaluate the result. Then this paper tries to analyze different kinds of data mining technologies and how they are used in e-commerce. Finally, we predict the development trend of web data mining in e-commerce domain. © 2013 IEEE.

Tian Y.,Chinese Academy of Sciences | Ping Y.,Xuchang University | Ping Y.,Beijing University of Posts and Telecommunications
Neural Networks | Year: 2014

Twin support vector machines (TWSVMs), as the representative nonparallel hyperplane classifiers, have shown the effectiveness over standard SVMs from some aspects. However, they still have some serious defects restricting their further study and real applications: (1) They have to compute and store the inverse matrices before training, it is intractable for many applications where data appear with a huge number of instances as well as features; (2) TWSVMs lost the sparseness by using a quadratic loss function making the proximal hyperplane close enough to the class itself. This paper proposes a Sparse Linear Nonparallel Support Vector Machine, termed as L1-NPSVM, to deal with large-scale data based on an efficient solver-dual coordinate descent (DCD) method. Both theoretical analysis and experiments indicate that our method is not only suitable for large scale problems, but also performs as good as TWSVMs and SVMs. © 2013 Elsevier Ltd.

Wang F.,Beijing University of Posts and Telecommunications | Wang X.,Columbia University
IEEE Transactions on Communications | Year: 2010

A new approach to modulation classification based on the Kolmogorov-Smirnov (K-S) test is proposed. The K-S test is a non-parametric method to measure the goodness of fit. The basic procedure involves computing the empirical cumulative distribution function (ECDF) of some decision statistic derived from the received signal, and comparing it with the CDFs or the ECDFs of the signal under each candidate modulation format. The K-S-based modulation classifiers are developed for various channels, including the AWGN channel, the flat-fading channel, the OFDM channel, and the channel with unknown phase and frequency offsets, as well as the non-Gaussian noise channel, for both QAM and PSK modulations. Extensive simulation results demonstrate that compared with the traditional cumulant-based classifiers, the proposed K-S classifiers offer superior classification performance, require less number of signal samples (thus is fast), and is more robust to various channel impairments. © 2010 IEEE.

Chen D.,Beijing University of Posts and Telecommunications
IEEE Transactions on Wireless Communications | Year: 2016

We consider a wireless transmission scheme based on randomized space-time spreading (STS) systems over massive multiple-input multiple-output (MIMO) channels. In the systems, the signals are spread by spreading matrices over time and antenna domains at the transmitter. We propose that the spreading matrices are generated from binary pseudo-noise (PN) and mutual quasi-orthogonal sequences, by partitioning each of the sequences into subsequences treated as real and imagination parts of rows or columns of a spreading matrix. We give a likelihood ascent search (LAS) detector for the STS systems and analyze its computational complexity. The number of multiplication and division operations for the LAS detector does not depend on its iterative process and the number of chips in the bit period. We use Monte Carlo method to solve the bit error rates (BERs) of the STS systems and to count numbers of evaluating bits in the LAS detectors. We choose the system parameters, such as the number of chips in the bit period and the transmission bit rates, according to BER performance and/or the numbers of evaluating bits attained from Monte-Carlo method. With the spreading matrices, the detection, and the suitable parameters, the STS systems achieve BERs near to their single-bit performance, which is the BER of a STS system with a single bit spread by orthonormal sequences at each transmitting antenna. We also compare our systems with V-BLAST-like spatial multiplexing systems with BPSK signals to show the improvement of the BER performance. © 2002-2012 IEEE.

Yinghui C.,Beijing University of Posts and Telecommunications
2011 IEEE 3rd International Conference on Communication Software and Networks, ICCSN 2011 | Year: 2011

Internet TV is a breakthrough point in the process of executing Triple Play-convergence of telecommunication networks, Internet and the broadcasting media. In the context of Triple Play, this article summarizes the great interests brought by the Internet TV development from multiple perspectives in order to promote its development in China. © 2011 IEEE.

Wang S.L.,Zhejiang Sci-Tech University | Li P.G.,Zhejiang Sci-Tech University | Zhu H.W.,Zhejiang Sci-Tech University | Tang W.H.,Beijing University of Posts and Telecommunications
Powder Technology | Year: 2012

An ethanolamine-assisted route has been designed for one-step synthesis of uniform CuO/Cu 2O composite hollow microspheres with controllable composition in an aqueous solution system. The influences of reaction time and temperature on the morphologies and composition of the resulting products were investigated. The content of Cu 2O in the composite hollow microspheres ranged from 10 to 84 wt % could be controlled by changing the reaction time and temperature. The formation process for such CuO/Cu 2O composite hollow microspheres was studied. The mesoporous CuO/Cu 2O composite hollow microspheres exhibited a higher photocatalytic activity for degradation of Rhodamine B under UV-light illumination than the single phase CuO samples. © 2012 Elsevier B.V.

Sun X.,Beijing University of Posts and Telecommunications | Zheng Y.,Fujian Normal University
International Journal of Bifurcation and Chaos | Year: 2014

We investigate the effects of time-periodic intercoupling strength on the spiking regularity of a clustered neuronal network. Inside the clustered neuronal network, each cluster has the same regular structure with each node modeled by a stochastic Hodgkin-Huxley neuronal model. From simulation results, we find that there exist some optimal frequencies of the time-periodic intercoupling strength, at which the spiking regularity of the considered clustered neuronal network becomes higher. When we consider the effects of the amplitude of time-periodic intercoupling strength, we find that the clustered neuronal network could exhibit more regular spiking activity at some intermediate amplitude for higher noise level; while for lower noise level, the spiking regularity of the neuronal network decreases with the amplitude increase. And the obtained results are independent of the cluster number. © 2014 World Scientific Publishing Company.

Qi L.,Beijing University of Posts and Telecommunications
Journal of the Optical Society of Korea | Year: 2016

Broadband metal-dielectric-metal terahertz filters composed of complementary rings are designed and demonstrated. Four samples with different parameters were fabricated. Results measured using THz time-domain spectroscopy system show excellent agreement with simulations. Compared with the broadband filters reported before, the complementary ring structure in our design is insensitive to any polarization at normal incidence due to symmetry of the ring. Furthermore, the influence of structure parameters (such as period, radius, slot width, thickness and incidence angles) on the transmission characteristics has been investigated theoretically. The encouraging results afforded by designing of the filters could find applications in broadband sensors, terahertz communication systems, and other emerging terahertz technologies. © 2016 Optical Society of Korea.

Shi Z.,Beijing University of Posts and Telecommunications
Advances in Information Sciences and Service Sciences | Year: 2012

In this paper, we explore the application of saliency information for perceptual video quality assessment of different network environment. The proposed hybrid assessment method considers three factors, such as video encoder feature, the video content feature and the network parameter. First we present an experiment to extract the saliency information of video, and then we characterize the correlation between the saliency information and the MOS using analytical models and empirical evaluation. We combine multiple factors from the video sequence using stepwise linear regression analysis. The final combined model includes three factors and provides significant gain over using the best single factor.

Yin H.,Beijing University of Posts and Telecommunications
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

In recent years, with the rapid development of a large number of short-distance wireless communication technology, wireless ad hoc network based on traditional mobile devices spreads rapidly, providing a new way for mobile users for data communication in the absence of wireless coverage area. This paper aims at shortcomings for popular social opportunistic network’s news propagation model: larger network delay, higher resource consumption and heavier network load, under the full consideration of the user's mobile device movement patterns, hobbies, the subjective intentions and so on, this paper presents a new message transmission model which based on user node attribute classification and subjective intention, selecting the users who has larger chances to meet and the most intensive users in the whole property contact network of relationships, expanding the accuracy and coverage of the message transmission as much as possible. © Springer International Publishing Switzerland 2015.

He J.,Beijing University of Technology | Peng Z.,Beijing University of Technology | Fu Z.,Beijing University of Technology | Wang C.,Beijing University of Technology | Fu X.,Beijing University of Posts and Telecommunications
Journal of Alloys and Compounds | Year: 2012

SnO 2-Ta 2O 5 based varistors doped with 0-2.0 mol% of ZnO were prepared by sintering the samples at 1450 °C for 2 h with conventional ceramic processing method. The doping effect of ZnO on the microstructural and electrical properties of the as-prepared SnO 2-Ta 2O 5 based varistor ceramics was investigated. The change in SnO 2 lattice parameter and EDX analysis both confirmed the doping of Zn ions into SnO 2 grains, although the identified phase was only SnO 2 (cassiterite) by X-ray diffraction in detection limit. The microstructure observation indicated that the doped ZnO can facilitate the sintering of the varistor ceramics. The measured electric-field/current-density characteristics of the samples revealed that the nonlinear exponents and varistor voltage increased with increasing doping amount of ZnO when the ZnO content was no more than 0.5 mol%; and more addition of ZnO would cause a decrease in nonlinear exponent and varistor voltage of the ceramic varistors. © 2012 Elsevier B.V. All rights reserved.

Zuo X.,Beijing University of Posts and Telecommunications | Murray C.C.,Auburn University | Smith A.E.,Auburn University
IEEE Transactions on Automation Science and Engineering | Year: 2014

Facility layout problems have drawn much attention over the years, as evidenced by many different versions and formulations in the manufacturing context. This paper is motivated by semiconductor manufacturing, where the floor space is highly expensive (such as in a cleanroom environment) but there is also considerable material handling amongst machines. This is an integrated optimization task that considers both material movement and manufacturing area. Specifically, a new approach combining multiobjective tabu search with linear programming is proposed for an extended double row layout problem, in which the objective is to determine exact locations of machines in both rows to minimize material handling cost and layout area where material flows are asymmetric. First, a formulation of this layout problem is established. Second, an optimization framework is proposed that utilizes multiobjective tabu search and linear programming to determine a set of non-dominated solutions, which includes both sequences and positions of machines. This framework is applied to various manufacturing situations, and compared with an exact approach and a popular multiobjective genetic algorithm optimization algorithm. Experimental results show that the proposed approach is able to obtain sets of Pareto solutions that are far better than those obtained by the alternative approaches. Note to Practitioners-Manufacturing facility layouts are typically designed with the singular focus of promoting minimum-distance material flows, as material handling costs increase with travel distance. However, the square footage required by a layout also contributes to manufacturing costs, as is especially true in cleanroom environments typically found in semiconductor manufacturing. This paper proposes a methodology for determining a set of Pareto optimal solutions, highlighting the tradeoff between minimizing material flow cost versus facility size. We demonstrate this approach on a commonly used layout configuration, where two rows of machines are separated by an aisle. Despite the straightforward problem description, determining optimal solutions to this problem is challenging. Our approach is shown to work efficiently on problems of realistic size and provide implementable machine layouts. © 2014 IEEE.

Xiang C.,Hangzhou Normal University | Shoushan L.,Beijing University of Posts and Telecommunications
Advances in Information Sciences and Service Sciences | Year: 2012

The usual method for extracting information fields of interest in the framework is by pattern matching. Using it, a wrapper implementer quickly and easily prepares wrapper specifications for a specified information source. This differs from previous approaches in that a wrapper generated in our framework focuses on extracting fields of interest from returned documents and not on analyzing their content. An implementer is not required to understand the whole structure of a specified information source.

Lu Z.-S.,Beijing University of Posts and Telecommunications | Ren W.-X.,Inner Mongolia University of Technology
Communications in Theoretical Physics | Year: 2014

Starting from a simple transformation, and with the aid of symbolic computation, we establish the relationship between the solution of a generalized variable coefficient Kadomtsev - Petviashvili (vKP) equation and the solution of a system of linear partial differential equations. According to this relation, we obtain Wronskian form solutions of the vKP equation, and further present N-soliton-like solutions for some degenerated forms of the vKP equation. Moreover, we also discuss the influences of arbitrary constants on the soliton and N-soliton solutions of the KPII equation. © 2013 Chinese Physical Society and IOP Publishing Ltd.

Zhu Y.,Jiangxi University of Science and Technology | Zheng Z.,Beijing Normal University | Yang J.,Beijing University of Posts and Telecommunications
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

The model of nonlocally coupled identical phase oscillators on complex networks is investigated. We find the existence of chimera states in which identical oscillators evolve into distinct coherent and incoherent groups. We find that the coherent group of chimera states always contains the same oscillators no matter what the initial conditions are. The properties of chimera states and their dependence on parameters are investigated on both scale-free networks and Erdös-Rényi networks. © 2014 American Physical Society.

Quan Q.,Beijing University of Posts and Telecommunications
ETRI Journal | Year: 2010

An optimal multiuser detection algorithm with a computational complexity of O(K log K) is proposed for the class of linear multiple-access systems which have constant cross-correlation values. Here the optimal multiuser detection is implemented by searching for a monotone sequence with maximum likelihood, under the ranking of sufficient statistics. The proposed algorithm is intuitive and concise. It is carried out in just two steps, and at each step only one kind of operation is performed. Also, the proposed algorithm can be extended to more complex systems having more than a single cross-correlation value.

Meng D.,Beihang University | Jia Y.,Beihang University | Du J.,Beijing University of Posts and Telecommunications | Zhang J.,Beihang University
Automatica | Year: 2014

This paper deals with formation control problems for multi-agent systems with nonlinear dynamics and switching network topologies. Using the nearest neighbor knowledge, a distributed algorithm is constructed by employing the iterative learning control approach. Sufficient conditions are given to obtain the desired relative formations of agents, which benefits from the strict positiveness of products of stochastic matrices. It is shown that the derived results can effectively work, although the network topologies dynamically change along both time and iteration axes and the corresponding directed graphs may not have spanning trees. Such result is also illustrated via numerical simulations. © 2013 The Authors. Published by Elsevier Ltd. All rights reserved.

Cheng X.,Peking University | Yu B.,Colorado State University | Yang L.,Colorado State University | Zhang J.,Beijing University of Posts and Telecommunications | And 3 more authors.
IEEE Wireless Communications | Year: 2014

Spectrum efficiency has long been at the center of mobile communication research, development, and operation. Today it is even more so with the explosive popularity of the mobile Internet, social networks, and smart phones that are more powerful than our desktops used to be not long ago. The discovery of spatial multiplexing via multiple antennas in the mid-1990s has brought new hope to boosting data rates regardless of the limited bandwidth. To further realize the potential of spatial multiplexing, the next leap will be accounting for the three-dimensional real world in which electromagnetic waves propagate. In this article we discuss fundamentals and key technical issues in developing and realizing 3D multi-input multi-output technology for next generation mobile communications. © 2014 IEEE.

Zheng Z.,Chinese University of Hong Kong | Zheng Z.,Beijing University of Posts and Telecommunications | Wu X.,Sun Yat Sen University | Zhang Y.,Chinese University of Hong Kong | And 2 more authors.
IEEE Transactions on Parallel and Distributed Systems | Year: 2013

Cloud computing is becoming popular. Building high-quality cloud applications is a critical research problem. QoS rankings provide valuable information for making optimal cloud service selection from a set of functionally equivalent service candidates. To obtain QoS values, real-world invocations on the service candidates are usually required. To avoid the time-consuming and expensive real-world service invocations, this paper proposes a QoS ranking prediction framework for cloud services by taking advantage of the past service usage experiences of other consumers. Our proposed framework requires no additional invocations of cloud services when making QoS ranking prediction. Two personalized QoS ranking prediction approaches are proposed to predict the QoS rankings directly. Comprehensive experiments are conducted employing real-world QoS data, including 300 distributed users and 500 real-world web services all over the world. The experimental results show that our approaches outperform other competing approaches. © 1990-2012 IEEE.

Lin P.,Chongqing University | Lin P.,Beijing University of Posts and Telecommunications | Ren W.,University of California at Riverside
IEEE Transactions on Automatic Control | Year: 2014

In this note, a constrained consensus problem is studied for multi-agent systems in unbalanced networks in the presence of communication delays. Here each agent needs to lie in a closed convex constraint set while reaching a consensus. The communication graphs are directed, dynamically changing, and not necessarily balanced and only the union of the graphs is assumed to be strongly connected among each time interval of a certain bounded length. The analysis is performed based on an undelayed equivalent system that is composed of a linear main body and an error auxiliary. To tackle the loss of symmetry caused by unbalanced graphs and communication delays, a novel approach is proposed. The idea is to estimate the distance from each agent to the intersection set of all agents' constraint sets based on the properties of the projection on convex sets so as to show consensus convergence by contradiction. It is shown that the error auxiliary vanishes as time evolves and the linear main body converges to a vector with an exponential rate as a separate system. It is also shown that the communication delays do not affect the consensus stability and constrained consensus is reached even if the communication delays are arbitrarily bounded. Finally, a numerical example is included to illustrate the obtained theoretical results. © 2013 IEEE.

Han T.M.,Beijing University of Posts and Telecommunications
Conference Proceedings of the 3rd International Symposium on Project Management, ISPM 2015 | Year: 2015

In this paper, based on the physical and value input-output table as well as the ultimate goal of maximizing corporate profits, we develop an enterprise input-output optimization model by adding total resource constraints and comprehensive balancing constraints among products. The model can be used to provide information and analytical support for making business decisions. We derive a set of equations to describe the model structure and discuss how the model can be used by managers for decisions of production planning or production capacity expansion. Instead of completely focusing on projects as the main managerial strategy, housing development and construction corporations should change it to incorporating various projects into the overall management system so that corporate resources can be fully utilized and thus profits can be maximized.

Wang L.,North China Electrical Power University | Gao Y.-T.,Beihang University | Qi F.-H.,Beijing University of Posts and Telecommunications
Annals of Physics | Year: 2012

Under investigation in this paper is a variable-coefficient modified Kortweg-de Vries (vc-mKdV) model describing certain situations from the fluid mechanics, ocean dynamics and plasma physics. N-fold Darboux transformation (DT) of a variable-coefficient Ablowitz-Kaup-Newell-Segur spectral problem is constructed via a gauge transformation. Multi-solitonic solutions in terms of the double Wronskian for the vc-mKdV model are derived by the reduction of the N-fold DT. Three types of the solitonic interactions are discussed through figures: (1) Overtaking collision; (2) Head-on collision; (3) Parallel solitons. Nonlinear, dispersive and dissipative terms have the effects on the velocities of the solitonic waves while the amplitudes of the waves depend on the perturbation term. © 2012 Elsevier Inc.

Zhang K.-J.,Beijing University of Posts and Telecommunications | Jia H.-Y.,Central University of Finance and Economics
International Journal of Theoretical Physics | Year: 2014

Recently, Cao et al. presented a weak blind signature scheme based on a genuinely entangled six -qubit state. However, we find there exists a security problem that the receiver of the signature can forge a valid signature without being caught. In order to show that, the detailed attack strategy and the potential improved ideas are proposed in this paper. © 2014, Springer Science+Business Media New York.

Wang J.,Nanjing Southeast University | Peng M.,Beijing University of Posts and Telecommunications | Jin S.,Nanjing Southeast University | Zhao C.,Nanjing Southeast University
IEEE Transactions on Wireless Communications | Year: 2014

Resource sharing between primary users (PUs) and secondary users (SUs) in cognitive radio (CR) networks is built on strict interference limitations. However, such limitations may be easily violated by SUs using imperfect SU-to-PU channel state information (CSI). In this paper, we propose a robust decentralized CR network design by explicitly taking into account imperfect SU-to-PU CSI from a game theoretical perspective. We formulate the CR network design as a generalized Nash equilibrium problem (GNEP), where the SUs compete with each other over the resources made available by the PUs, who are protected by the robust aggregate interference constraints. We establish a framework-based generalized variational inequality (GVI) theory to analyze the formulated robust GNEP. It is shown that the solution to the robust GNEP can be obtained by solving a GVI, which can be addressed by a distributed pricing mechanism in the CR network, where the SUs play a priced NEP with given prices and the PUs are in charge of setting prices. Then, we propose distributed algorithms, along with their convergence properties, for the SUs to solve the priced NEP and for the PUs to update prices, respectively. We also provide an efficient method to compute the optimal transmit strategy of each SU via convex optimization. © 2014 IEEE.

Xu J.,CAS Shanghai Institute of Microsystem and Information Technology | Wang J.,University of Electronic Science and Technology of China | Zhu Y.,Wuhan University of Technology | Yang Y.,Nanjing Southeast University | And 3 more authors.
IEEE Communications Magazine | Year: 2014

The fifth generation mobile networks will be developed to improve area spectral and energy efficiency, and provide uniform user experience. Hyper-dense small cell deployment can move devices closer to the wireless network and satisfy 5G system requirements. The main challenge of this network deployment results from the random deployment, dynamic on-off, flexible connection to cellular core networks, and flat system architecture of 5G systems. Therefore, conventional network planning and radio resource management, which depend on a central control node, cannot be applied to small cell networks. In this article some cooperative distributed radio resource management algorithms for time synchronization, carrier selection, and power control are discussed for hyper-dense small cell deployment. © 2014 IEEE.

Shao J.,Zhejiang GongShang University | Shao J.,Beijing University of Posts and Telecommunications
Information Sciences | Year: 2014

A verifiable (k,t,n) multi-secret sharing scheme (VMSS) allows a dealer to share k secrets among n players. In particular, (1) the secret shadow given by the dealer or some player can be verifiable and (2) t or more players can cooperate to reveal the k secrets, while less than t players cannot reveal any secret. VMSS can be used in many applications, such as access control. However, the existing VMSS schemes either require costly computation, or miss some important properties of VMSS. These two weaknesses make the VMSS scheme not so good as expected. In this paper, we propose a novel VMSS scheme which does not need any costly computation, while holds all properties of VMSS. © 2014 Elsevier Inc. All rights reserved.

Ma L.,Beijing University of Posts and Telecommunications
Information Sciences | Year: 2014

Based on the notions of neighborhood and complementary neighborhood, we consider the classification of coverings in the covering rough set theory. We present a classification rule under which the coverings on a universe U are classified such that for any given pair of neighborhood (or complementary neighborhood)-based lower and upper approximation operators on U, all the different coverings in the same class generate the same pair of lower and upper approximations of each XU. We show that there is a one to one correspondence between the equivalence classes of coverings and the topologies of the universe. Thus the number of the equivalence classes of coverings is equal to the number of topologies of the universe, and therefore, this number is much smaller than that of the coverings. We also give an illustrative example to show how we can classify some given coverings by calculating the topologies. Moreover, based on the relationship between the neighborhood and the complementary neighborhood, we find that each class of coverings has a dual class, and each pair of approximation operators has a dual pair of approximation operators. For a finite universe, considering one pair of approximation operators under one equivalence class of coverings is equivalent to considering its dual approximation operator pair under the dual class of coverings. Finally, we also present a sufficient condition under which, for any given pair of neighborhood-based lower and upper approximation operators, two coverings of the universe U generate the same pair of approximations of each XU if and only if they belong to the same equivalence class. © 2013 Elsevier Inc. All rights reserved.

Du H.,Baoji University of Arts And Sciences | Wen Q.,Beijing University of Posts and Telecommunications
Information Sciences | Year: 2014

Proxy multi-signature allows a group of original signers to delegate their signing capabilities to a proxy signer in such a way that the proxy signer can sign messages on behalf of the group of original signers. Existing constructions of proxy multi-signatures are based on traditional Public Key Infrastructure or Identity-based Public Key Setting, but the former needs certificates which bring about many certificate management problems, and the latter has a drawback of key escrow. In contrast to the existing constructions, in this paper, we study proxy multi-signature in Certificateless Public Key Cryptography (CL-PKC) which combines the advantages of both certificate-based and identity-based cryptosystems as it avoids the use of certificates and does not suffer from key escrow. We provide the definition and the security model for Certificateless Proxy Multi-Signature (CLPMS), and propose the first CLPMS scheme which is proved to be secure in the random oracle model under the computational Diffie-Hellman assumption. Our scheme is computationally efficient and has the property that the size of a proxy multi-signature is independent of the number of the original signers. © 2013 Elsevier Inc. All rights reserved.

Lu Z.-S.,Beijing University of Posts and Telecommunications
Communications in Theoretical Physics | Year: 2011

Employing a constructive algorithm and the symbolic computation, we obtain a new explicit bi-soliton-like solution of the asymmetric Nizhnik-Novikov- Veselov equation. The solution contains two arbitrary functions which indicates that it can model various bi-soliton-like waves. In particular, specially choosing the arbitrary functions, we find some interesting bi-solitons with special shapes, which possess the traveling property of the traditional bi-solitons. We show the evolution of such bi-solitons by figures. © 2011 Chinese Physical Society and IOP Publishing Ltd.

Wang L.,Beijing University of Posts and Telecommunications | Wang L.,Japan National Institute of Information and Communications Technology | Pan Y.,Communication University of China | Zhang Z.,Orange S.A. | Yang Y.,Beijing University of Posts and Telecommunications
Information Sciences | Year: 2011

At PKC 2006, Chevallier-Mames, Paillier, and Pointcheval proposed discrete logarithm based encryption schemes that are partially homomorphic, either additively or multiplicatively and announced an open problem: finding a discrete logarithm based cryptosystem that would help realize fully additive or multiplicative homomorphism. In this study, we achieve this goal by enclosing two opposite settings on the discrete logarithm problems (DLP) simultaneously: the first setting is that DLP over Zp0 (where p0 - 1 is smooth) is used to encode messages, while the second setting is that DLP over Zp (where p - 1 is non-smooth, i.e., containing large prime factors) is used to encrypt plaintexts. Then, based on the proposed scheme, novel protocols for secure data aggregation in wireless sensor networks are presented. Finally, taking Paillier's factoring-based additively homomorphic encryption schemes as the reference framework, we present detailed performance comparisons and further enhancement. © 2011 Elsevier Inc. All rights reserved.

Wang S.,Beijing University of Posts and Telecommunications | Chen C.,Nokia Inc. | Ma J.,Nokia Inc.
APWCS 2010 - 2010 Asia-Pacific Conference on Wearable Computing Systems | Year: 2010

Recognizing the transportation modes of people's daily living is an important research issue in the pervasive computing. Prior research in this field mainly uses Global Positioning System (GPS), Global System for Mobile Communications (GSM) or their combination with accelerometer to recognize transportation modes, such as walking, driving, etc. In this paper, we will introduce transportation mode recognition on mobile phones only using embedded accelerometer. In order to deal with uncertainty of position and orientation of mobile phone, acceleration synthesization based method and acceleration decomposition based method are introduced. Performance comparison indicates that acceleration synthesization based method outperforms acceleration decomposition based method. We will discuss the factors affect the recognition accuracy of acceleration decomposition based method and present potential improvements. © 2010 IEEE.

Zhang M.,Beijing Normal University | Yang J.-Z.,Beijing University of Posts and Telecommunications
Communications in Theoretical Physics | Year: 2011

In this work, we consider an evolutionary prisoner's dilemma game on a homogeneous random network with the richest-following strategy adoption rule. By constructing homogeneous random networks from a regular ring graph, we investigate the effects of topological randomness on cooperation. In contrast to the ordinary view that the presence of small amount of shortcuts in ring graphs favors cooperation, we find the cooperation inhibition by weak topological randomness. The explanations on the observations are presented. © 2011 Chinese Physical Society and IOP Publishing Ltd.

Meng D.,Beihang University | Jia Y.,Beihang University | Du J.,Beijing University of Posts and Telecommunications | Yu F.,Henan Polytechnic University
International Journal of Adaptive Control and Signal Processing | Year: 2011

This paper is devoted to designing iterative learning control (ILC) for multiple-input multiple-output discrete-time systems that are subject to random disturbances varying from iteration to iteration. Using the super-vector approach to ILC, statistical expressions are presented for both expectation and variance of the tracking error, and time-domain conditions are developed to ensure their asymptotic stability and monotonic convergence. It shows that time-domain conditions can be tied together with an H∞-based condition in the frequency domain by considering the properties of block Toeplitz matrices. This makes it possible to apply the linear matrix inequality technique to describe the convergence conditions and to obtain formulas for the control law design. Furthermore, the H∞-based approach is shown applicable to ILC design regardless of the system relative degree, which can also be used to address issues of model uncertainty. For a class of systems with a relative degree of one, simulation tests are provided to illustrate the effectiveness of the H∞-based approach to robust ILC design. © 2011 John Wiley & Sons, Ltd.

Cui Y.,Tsinghua University | Li W.,Beijing University of Posts and Telecommunications | Cheng X.,George Washington University
Proceedings - IEEE INFOCOM | Year: 2011

In this study, we investigate the problem of partially overlapping channel assignment to improve the performance of 802.11 wireless networks. We first derive a novel interference model that takes into account both the adjacent channel separation and the physical distance of the two nodes employing adjacent channels. This model defines node orthogonality, which states that two nodes over adjacent channels are orthogonal if they are physically sufficiently separated. We propose an approximate algorithm MICA to minimize the total interference for throughput maximization. Extensive simulation study has been performed to validate our design and to compare the performances of our algorithm with those of the state-of-the-art. © 2011 IEEE.

Peng J.,Guangzhou University | Xiong J.,Guangzhou University | Xu G.,Beijing University of Posts and Telecommunications
Physica A: Statistical Mechanics and its Applications | Year: 2014

In this paper, the discrete random walks on the recursive non-fractal scale-free trees (NFSFT) are studied, and a kind of method to calculate the analytic solutions of the mean first-passage time (MFPT) for any pair of nodes, the mean trapping time (MTT) for any target node and mean diffusing time (MDT) for any starting node are proposed. Furthermore, we compare the trapping efficiency and diffusion efficiency between any two nodes of NFSFT by using the MTT and the MDT as the measures of trapping efficiency and diffusion efficiency respectively, and find the best (or worst) trapping sites and the best (or worst) diffusion sites. The results show that the two hubs of NFSFT are not only the best trapping site but also the worst diffusion site, and that the nodes which are the farthest nodes from the two hubs are not only the worst trapping sites but also the best diffusion sites. Furthermore, we find that the ratio between the maximum and minimum of MTT grows logarithmically with network order, but the ratio between the maximum and minimum of MDT is almost equal to 1. The results imply that the trap's position has great effect on the trapping efficiency, but the position of starting node has little effect on diffusion efficiency. Finally, the simulation for random walks on NFSFT is done, and it is consistent with the derived results. © 2014 Elsevier B.V. All rights reserved.

Li T.,Beijing Normal University | Deng F.-G.,Beijing Normal University | Deng F.-G.,Beijing University of Posts and Telecommunications
International Journal of Theoretical Physics | Year: 2014

We present an efficient entanglement concentration protocol (ECP) for partially entangled four-photon χ-type states in the first time with only linear optical elements and single-photon detectors. Without any ancillary particles, the parties in quantum communication network can obtain a subset of four-photon systems in the standard {pipe}χ 00〉 state from a set of four-photon systems in a partially entangled χ-type state with the parameter-splitting method developed by Ren et al. (Phys. Rev. A 88:012302, 2013). The present ECP has the optimal success probability which is determined by the component with the minimal probability amplitude in the initial state. Moreover, it is easy to implement this ECP in experiment. © 2014 Springer Science+Business Media New York.

Liu Y.Y.,Beijing University of Posts and Telecommunications
Advanced Materials Research | Year: 2014

In this paper, a wideband variable-