Showing papers by "Beijing University of Posts and Telecommunications published in 2011"
19 Dec 2011
TL;DR: The background, basic characteristics, data model of NoSQL, and the mainstream NoSQL databases are separately described in detail, and some properties are extracted to help enterprises to choose NoSQL.
Abstract: With the development of the Internet and cloud computing, there need databases to be able to store and process big data effectively, demand for high-performance when reading and writing, so the traditional relational database is facing many new challenges. Especially in large scale and high-concurrency applications, such as search engines and SNS, using the relational database to store and query dynamic user data has appeared to be inadequate. In this case, NoSQL database created. This paper describes the background, basic characteristics, data model of NoSQL. In addition, this paper classifies NoSQL databases according to the CAP theorem. Finally, the mainstream NoSQL databases are separately described in detail, and extract some properties to help enterprises to choose NoSQL.
746 citations
15 Apr 2011
TL;DR: The Markov Random Walk model is applied to rank a network node based on its resource and topological attributes and shows that the topology-aware node rank is a better resource measure and the proposed RW-based algorithms increase the long-term average revenue and acceptance ratio.
Abstract: Virtualizing and sharing networked resources have become a growing trend that reshapes the computing and networking architectures. Embedding multiple virtual networks (VNs) on a shared substrate is a challenging problem on cloud computing platforms and large-scale sliceable network testbeds. In this paper we apply the Markov Random Walk (RW) model to rank a network node based on its resource and topological attributes. This novel topology-aware node ranking measure reflects the relative importance of the node. Using node ranking we devise two VN embedding algorithms. The first algorithm maps virtual nodes to substrate nodes according to their ranks, then embeds the virtual links between the mapped nodes by finding shortest paths with unsplittable paths and solving the multi-commodity flow problem with splittable paths. The second algorithm is a backtracking VN embedding algorithm based on breadth-first search, which embeds the virtual nodes and links during the same stage using node ranks. Extensive simulation experiments show that the topology-aware node rank is a better resource measure and the proposed RW-based algorithms increase the long-term average revenue and acceptance ratio compared to the existing embedding algorithms.
503 citations
TL;DR: An improved biometrics-based remote user authentication scheme that removes the aforementioned weaknesses and supports session key agreement is proposed.
257 citations
TL;DR: In this paper, a generalized coupled-line circuit structure for a dual-band Wilkinson power divider is proposed, which is composed of two coupled lines with different even-and odd-mode characteristic impedances and two lumped resistors.
Abstract: A novel generalized coupled-line circuit structure for a dual-band Wilkinson power divider is proposed. The proposed power divider is composed of two coupled lines with different even- and odd-mode characteristic impedances and two lumped resistors. Using rigorous even- and odd-mode analysis, the analytical design equations for this proposed power divider are obtained and the ideal closed-form scattering parameters are constructed. Since the traditional transmission line is a special case of coupled line (coupled coefficient is zero), it is found that traditional noncoupled-line dual-band (including single band) Wilkinson power dividers and previous dual-band coupled-line power dividers are special cases of this generalized power divider. As a typical example, which could only be designed by using this given design equations, a compact microstrip 3-dB power divider operating at both 1.1 and 2.2 GHz is designed, fabricated, and measured. There is good agreement between calculated and measured results.
224 citations
TL;DR: The challenges and key scientific problems involved in IoT development are presented and the current research project supported by the National Basic Research Program of China (973 Program) is introduced.
Abstract: The Internet of Things (IoT) is aimed at enabling the interconnection and integration of the physical world and the cyber space. It represents the trend of future networking, and leads the third wave of the IT industry revolution. In this article, we first introduce some background and related technologies of IoT and discuss the concepts and objectives of IoT. Then, we present the challenges and key scientific problems involved in IoT development. Moreover, we introduce the current research project supported by the National Basic Research Program of China (973 Program). Finally, we outline future research directions.
224 citations
TL;DR: This paper presents an energy-efficient opportunistic routing strategy, denoted as EEOR, and extensive simulations in TOSSIM show that the protocol EEOR performs better than the well-known ExOR protocol in terms of the energy consumption, the packet loss ratio, and the average delivery delay.
Abstract: Opportunistic routing, 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.
216 citations
TL;DR: In this paper, the parity-check gates constructed by the cavity-spin-coupling system provide a different method for the entanglement purification of electron-spin entangled states.
Abstract: We present an entanglement purification protocol and an entanglement concentration protocol for electron-spin entangled states, resorting to quantum-dot spin and optical-microcavity-coupled systems. The parity-check gates (PCGs) constructed by the cavity-spin-coupling system provide a different method for the entanglement purification of electron-spin entangled states. This protocol can efficiently purify an electron ensemble in a mixed entangled state. The PCGs can also concentrate electron-spin pairs in less-entangled pure states efficiently. The proposed methods are more flexible as only single-photon detection and single-electron detection are needed.
199 citations
TL;DR: By proving that the readjusting procedure works, a theoretical proof is given to justify the method succeeded in embedding and extracting, and the proposed method not only has an acceptable image quality but also provides a large embedding capacity.
187 citations
TL;DR: The new matrix decomposition theorems for Hermitian positive semidefinite matrices are proven by construction in this paper, and it is demonstrated that the constructive procedures can be implemented efficiently, stably, and accurately.
Abstract: In this paper, we present several new rank-one decomposition theorems for Hermitian positive semidefinite matrices, which generalize our previous results in Huang and Zhang (Math Oper Res 32(3):758–768, 2007), Ai and Zhang (SIAM J Optim 19(4):1735–1756, 2009). The new matrix rank-one decomposition theorems appear to have wide applications in theory as well as in practice. On the theoretical side, for example, we show how to further extend some of the classical results including a lemma due to Yuan (Math Program 47:53–63, 1990), the classical results on the convexity of the joint numerical ranges (Pang and Zhang in Unpublished Manuscript, 2004; Au-Yeung and Poon in Southeast Asian Bull Math 3:85–92, 1979), and the so-called Finsler’s lemma (Bohnenblust in Unpublished Manuscript; Au-Yeung and Poon in Southeast Asian Bull Math 3:85–92, 1979). On the practical side, we show that the new results can be applied to solve two typical problems in signal processing and communication: one for radar code optimization and the other for robust beamforming. The new matrix decomposition theorems are proven by construction in this paper, and we demonstrate that the constructive procedures can be implemented efficiently, stably, and accurately. The URL of our Matlab programs is given in this paper. We strongly believe that the new decomposition procedures, as a means to solve non-convex quadratic optimization with a few quadratic constraints, are useful for many other potential engineering applications.
180 citations
TL;DR: This paper shows that in previous AQS protocols the receiver, Bob, can realize existential forgery of the sender's signature under known message attack, and the sender, Alice, can successfully disavow any of her signatures by simple attack.
Abstract: As a new model for signing quantum messages, arbitrated quantum signature (AQS) has recently received a lot of attention. In this paper we study the cryptanalysis of previous AQS protocols from the aspects of forgery and disavowal. We show that in these protocols the receiver, Bob, can realize existential forgery of the sender's signature under known message attack. Bob can even achieve universal forgery when the protocols are used to sign a classical message. Furthermore, the sender, Alice, can successfully disavow any of her signatures by simple attack. The attack strategies are described in detail and some discussions about the potential improvements of the protocols are given. Finally we also present several interesting topics on AQS protocols that can be studied in future.
169 citations
16 May 2011
TL;DR: This paper survey's recent Mobile Cloud Computing architecture, application partition & offloading, and context-aware service, and a concept model has been proposed to analyze related research work.
Abstract: The rapid development of mobile computing and cloud computing trigger novel computing paradigm-----Mobile Cloud Computing. This paper review current research effort towards Mobile Computing. First, we present several challenges for the design of Mobile Cloud Computing service. Second, a concept model has been proposed to analyze related research work. Third, we survey recent Mobile Cloud Computing architecture, application partition & offloading, and context-aware service.
15 May 2011
TL;DR: The simulation results show that the proposed method is the optimal resource allocation method when the D2D pair locates at the most part of the cell area in both uplink and downlink.
Abstract: Device-to-Device (D2D) communication will become an important technology in future networks with the increase of the requirements of local communication services. The interference between cellular communication and D2D communication can be coordinated by proper power control and resource allocation. In this paper, we analyze the resource allocation methods for D2D communication underlaying cellular networks. A novel resource allocation method that D2D can reuse the resources of more than one cellular user is proposed. After that, we discuss the selection of the optimal resource allocation method from the proposed method and the conventional methods. Finally, the performance of different methods is evaluated through numerical simulation. The simulation results show that the proposed method is the optimal resource allocation method when the D2D pair locates at the most part of the cell area in both uplink and downlink. The proposed method can improve the sum throughput of cellular communication and D2D communication significantly.
TL;DR: 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.
TL;DR: In this article, the magnetic and dielectric properties of the as-prepared Ni-Zn ferrites were investigated using X-ray diffraction data, showing that the saturation magnetization and the coercivity increased with increasing substitution level, x, and the Curie temperature fluctuating between 308 and 320°C.
TL;DR: Based on an analytical framework of such principles, the authors reviewed China Mobile's ecosystem, and identified its success factors and problems, and indicated that a complete ecosystem, where mobile network operators collaborate closely with value-added service providers, content/application providers, equipment and device manufacturers, and other involved organizations, can promote the development of mobile data services substantially.
TL;DR: In this paper, the authors further investigate the covering rough sets based on neighborhoods by approximation operations and show that the upper approximation based on neighborhood can be defined equivalently without using neighborhoods.
TL;DR: A refractive index (RI) sensor based on a novel fiber structure that consists of a single-mode-multimode-single-mode (SMS) fiber structure followed by a fiber Bragg grating was demonstrated.
Abstract: A refractive index (RI) sensor based on a novel fiber structure that consists of a single-mode-multimode-single-mode (SMS) fiber structure followed by a fiber Bragg grating was demonstrated The multimode fiber in the SMS structure excites cladding modes within output single-mode fiber (SMF) and recouple the reflected cladding Bragg wavelength to the input SMF core By measuring the relative Bragg wavelength shift between core and cladding Bragg wavelengths, the RI can be determined Experimentally we have achieved a maximum sensitivity of 733 nm/RIU (RI unit) at RI range from 1324 to 1439
TL;DR: It is found that traffic matrix in time-frequency domain owns the more obvious sparsity than in time domain, which brings it into the field of compressive sensing that is a generic technique for data reconstruction.
TL;DR: A hierarchical cooperative relay-based heterogeneous network (HCRHeNet) to support both unicast and multicast services, where hierarchical Cooperative relay nodes are deployed to provide a cost-effective coverage extension based on the convergence of heterogeneous radio networks is presented.
Abstract: This article presents a hierarchical cooperative relay-based heterogeneous network (HCRHeNet) to support both unicast and multicast services, where hierarchical cooperative relay nodes are deployed to provide a cost-effective coverage extension based on the convergence of heterogeneous radio networks. The underlined HCR-HeNet divides its coverage into three layers: hierarchical cooperative basic layer, homogeneous cooperative enhanced layer, and heterogeneous cooperative extended layer. In the hierarchical cooperative basic layer, highspeed data transmission is enabled using highorder modulation and coding schemes for unicast services, and hierarchical modulation schemes for multicast services. In the homogeneous cooperative enhanced layer, where users may be located near a cell boundary and thus need the help of relay nodes, cooperative homogeneous diversity gain can be achieved. In the heterogeneous cooperative extended layer, heterogeneous cooperative diversity gain guarantees the convergence and interworking of multiradio access networks. The key techniques in the physical and MAC layers are identified. Issues in the application of cognitive radio and self-organized networking techniques in HCR-HeNet are also discussed. Finally, a physical layer testbed for the proposed HCR-HeNet with multicast services is introduced.
13 Oct 2011
TL;DR: In the improved algorithm, load and processing power are quantified, and single exponential smoothing forecasting mechanism is added, and the article proves by experiments that the new algorithm can reduce the server load tilt, and improve client service quality effectively.
Abstract: Because of the elastic service capability of cloud computing platform, more and more applications are moved here, which makes efficient load balancing into a bottleneck. Considering the unique features of long-connectivity applications which are increasingly popular nowadays, an improved algorithm is proposed based on the weighted least connection algorithm. In the new algorithm, load and processing power are quantified, and single exponential smoothing forecasting mechanism is added. Finally, the article proves by experiments that the new algorithm can reduce the server load tilt, and improve client service quality effectively.
TL;DR: The results show that both the maximum transmit power limit and the interference power constraint cause the outage saturation phenomenon, and more relays for secondary system can provide better outage performance.
Abstract: In this letter, considering a cognitive relay network with the maximum transmit power limit in a spectrum sharing scenario, the exact outage probability of secondary system is derived over Rayleigh fading channels, and the theoretical analysis is validated by simulations. The results show that both the maximum transmit power limit and the interference power constraint cause the outage saturation phenomenon, and more relays for secondary system can provide better outage performance.
10 Apr 2011
TL;DR: This paper proposes an efficient and effective QoS-aware service selection approach that employs cloud model to compute the QoS uncertainty for pruning redundant services while extracting reliable services and mixed integer programming is used to select optimal services.
Abstract: Cloud computing is Internet-based computing where computing resources are offered over the Internet as scalable, on-demand services. Web services are widely employed for building distributed cloud applications. Performance of web services may fluctuate due to the dynamic Internet environment, which makes the Quality-of-Service (QoS) inherently uncertain. With the increase of Web services in the Internet, selecting the optimal service from a set of functionally equivalent candidates becomes an important research problem. In this paper, we propose an efficient and effective QoS-aware service selection approach. Our approach first employs cloud model to compute the QoS uncertainty for pruning redundant services while extracting reliable services. Then, mixed integer programming is used to select optimal services. The experimental results show that our approach can provide reliable and efficient optimal service selection for users.
13 Oct 2011
TL;DR: This paper introduces state-of-the-art Mobile Cloud Computing and its implementation methods, investigates some critical issues to be solved and point-out further future research directions.
Abstract: In recent years cloud computing has gained a momentum and is transforming the internet computing infrastructure. Also the mobile applications and mobile devices are developing rapidly. Cloud computing is anticipated to bring an innovation in mobile computing, where the mobile devices can use clouds for data processing, storage and other intensive operations. Already there are some mobile cloud applications for example Google's Map, Gmail for iPhone and Cisco's WebEx on iPad, however these applications are using the Software as a Service model. In this paper we introduce state-of-the-art Mobile Cloud Computing and its implementation methods. We also investigate some critical issues to be solved and point-out further future research directions.
TL;DR: A distributed fiber optic vibration sensor is described, in which two Michelson interferometers are used as phase detectors and two 3×3 couplers are deployed to demodulate the time-varying phase change caused by vibration.
Abstract: A distributed fiber optic vibration sensor is described, in which two Michelson interferometers are used as phase detectors and two 3×3 couplers are deployed to demodulate the time-varying phase change caused by vibration. The two interferometers are separated by four wavelength division multiplexers. The position of the vibration is obtained by signal correlation, which can be used as a perimeter security sensor to locate the intruder. The experimental results with a 4012 m fiber sensor are discussed.
TL;DR: Analytical proofs and simulation results show that energy-efficient information reliability can be guaranteed in an unreliable wireless environment with the help of the proposed schemes.
Abstract: Energy-efficient and reliable transmission of sensory information is a key problem in wireless sensor networks. To save more energy, in-network processing such as data fusion is a widely used technique, which, however, may often lead to unbalanced information among nodes in the data fusion tree. Traditional schemes aim at providing reliable transmission to individual data packets from source node to the sink, but seldom offer the desired reliability to a data fusion tree. In this paper, we explore the problem of Minimum Energy Reliable Information Gathering (MERIG) when performing data fusion. By adaptively using redundant transmission on fusion routes without acknowledgments, packets with more information are delivered with higher reliability. For different data fusion topologies, such as star, chain, and tree, we provide optimal solutions to compute the number of transmissions for each node. We also propose practical, distributed approximation algorithms for chain and tree topologies. Analytical proofs and simulation results show that energy-efficient information reliability can be guaranteed in an unreliable wireless environment with the help of our proposed schemes.
TL;DR: It is shown that the eavesdropper Eve can totally obtain the session key by sending entangled qubits as the fake signal to Alice and performing collective measurements after Alice's encoding, just like a dense-coding communication between Eve and Alice.
Abstract: Cryptanalysis is an important branch in the study of cryptography, including both the classical cryptography and the quantum one. In this paper we analyze the security of two three-party quantum key distribution protocols (QKDPs) proposed recently, and point out that they are susceptible to a simple and effective attack, i.e., the dense-coding attack. It is shown that the eavesdropper Eve can totally obtain the session key by sending entangled qubits as the fake signal to Alice and performing collective measurements after Alice's encoding. The attack process is just like a dense-coding communication between Eve and Alice, where a special measurement basis is employed. Furthermore, this attack does not introduce any errors to the transmitted information and consequently will not be discovered by Alice and Bob. The attack strategy is described in detail and a proof for its correctness is given. Finally, the root cause of this insecurity and a possible way to improve these protocols are discussed.
01 Mar 2011
TL;DR: The adaptive non-uniform mutation operation borrowed from evolutionary algorithm is incorporated into simulated annealing for new solution generation and theoretical analysis and simulation experiments illustrate the consistent excellent performance and the possible application of nonu-SA algorithm.
Abstract: 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.
15 May 2011
TL;DR: A handover optimization algorithm based on the UE's mobility state is proposed and the comparison between the proposed algorithm and the traditional handover control algorithm shows that the algorithms proposed have aSignalling overhead reduction in the signalling overhead.
Abstract: Femtocell is a small access point using the wire broadband connections or wireless technologies to access the mobile operator's network for the user equipment(UE), which can provide better indoor coverage and satisfy the upcoming demand of high data rate for wireless communication system.Femtocell related handover cost reduction is one of the important targets in LTE-Advanced SON (Self-Organising Networks). In this paper, a handover optimization algorithm based on the UE's mobility state is proposed. An analytical model was presented for the handover signalling cost analysis. Numerical results are provided to compare the signalling cost of different handover management schemes. The comparison between the proposed algorithm and the traditional handover control algorithm shows that the algorithms proposed in this paper have a significant reduction in the signalling overhead.
01 Jan 2011
TL;DR: The future direction for the integration of Internet technology and technology on IOT, the technology of body sensor network and information services are suggested and the possibility and related issues of providing advanced services for human health management in the real world are analyzed.
Abstract: Internet technology provides various services via network. With the diversification of terminals and development of internet technology, internet technology has come into the stage of Next Generation Network(NGN) technology. Comparing with the current Internet technology that provides services in the imaginary space, the technology on Internet of Things (IOT) is based on real word. It links things together via sensors and wireless communication technology to collect a variety of information on the condition of people and their surrounding space in the real world. The combination of Internet technology and Technology on IOT integrates physical world and imaginary space on a shared platform to eliminate the constraints of imaginary space and provide intricate, diverse, and advanced services focusing on people, which have not been achieved [1]. The future direction for the integration of Internet technology and technology on IOT, the technology of body sensor network and information services are suggested. This paper analyze the possibility and related issues of providing advanced services for human health management in the real world and research direction of medical technology on IOT.
TL;DR: The confirmation experiment results have indicated the proposed clustering algorithm has more superior performance than other methods such as low energy adaptive clustering hierarchy (LEACH) and energy efficient unequal clustering (EEUC).