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SDSA: A Framework of a Software-Defi ned Security Architecture

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China Communications 2016年第2期13卷 178-188页

作者： LIU Yanbing LU Xingyu JIAN Yi XIAO Yunpeng Chongqing Engineering Laboratory of network and Information Security Chongqing University of Posts and Telecommunications

The fact that the security facilities within a system are closely coupled and the security facilities between systems are unconnected results in an isolated protection structure for systems, and gives rise to a serious challenge to system security integrations and system controls. Also, the need for diversified services and flexible extensions of network security asks for more considerations and contribu?tions from the perspective of software engineering in the process of designing and constructing security systems. Based on the essence of the virtualization technique and the idea of software-defined networks, we in this paper propose a novel software-defi ned security architecture for systems. By abstracting the traditional security facilities and techniques, the proposed security architecture provides a new, simple, effective, and programmable framework in which security operations and security controls can be decoupled, and thereby reduces the software module sizes, decreases the intensity of software deve?lopments, and improves the security extensibility of systems.

关键词： information security networksecurity security architecture software-definedsecurity

Temperature stability of magnetic field for periodic permanent-magnet focusing system

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Rare Metals 2014年第2期33卷 180-184页

作者： Li Li Jian-Ya Chen Yun-Jie Liu Beijing Key Laboratory of network System Architecture and Convergence Beijing University of Posts and Telecommunications

In this study, finite element analysis based on an Ansoft Maxwell software was used to reveal the temperature stability of a magnet ring and the equivalent structural periodic permanent-magnet（PPM） focusing system. It is found that with the temperature increasing, the decrease rate of magnetic induction peak（Bz）maxof single magnet ring is greater than that of remanence Brof magnet in the range from room temperature to 200 °C, however,the PPM focusing system do have the same temperature characteristics of permanent-magnet materials. It indicates that the magnetic temperature properties of the PPM system can be effectively controlled by adjusting the temperature properties of the magnets. Moreover, the higher permeability of the magnets indicates the less Hcb, giving rise to lower magnetic induction peak （Bz）′max： Finally, it should be noted that the magnetic orientation deviation angle θ（／15°） of permanent magnets has little effect on the focusing magnetic field of the PPM system at different temperatures and the temperature stability. The obtained results are beneficial to the design and selection of permanent magnets for PPM focusing system.

关键词： Periodic permanent-magnets focusing system Rare earth permanent magnets Finite element simulation Temperature stability Wireless underground sensor network

Exploring Mobile Learning Tools Used in Autonomous Learning:a Perspective from China

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Journal of Donghua University(English Edition) 2015年第2期32卷 314-317页

作者：葛子刚 School of network Education Beijing University of Posts and Telecommunications

With the development of mobile technologies,mobile learning has become a trend and a necessary means in the e-learning environment.E-learners' autonomous learning processes can also be facilitated through the adoption of various mobile learning *** learning tools can be classified into different types according to their different features and *** learning devices,mobile learning software,mobile learning resources,and mobile learning services are the four types of learning tools suggested in the *** mobile learning tools are proven to be able to fulfill different needs of autonomous learning.

关键词： autonomous fulfill adoption proven interactive popularity files classified necessity speaking

Survivability analysis of wireless Ad hoc network using stochastic reward nets

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Journal of Harbin Institute of Technology(New Series) 2008年第4期15卷 535-539页

作者：赵靖崔刚刘宏伟王慧强 dept.of Computer Harbin Engineering University dept.of Computer Harbin Institute of Technology

To provide services in presence of failures or attacks in a timely manner, the network survivability was analyzed. Based on stochastic Petri nets, we put forward an effective model for ad hoe network and adopt a two-phase approach consisting of the steady-state availability analysis and the system transient performance analysis, then provide a quantitative approach for analysis of the network survivability. The results show that the proposed model is useful for the design and evaluation of the wireless ad hoc network.

关键词： survivability availability ad hoc network stochastic Petri nets

Compressed sensing based channel estimation used in non-sample-spaced multipath channels of OFDM system

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The Journal of China Universities of Posts and telecommunications 2015年第2期22卷 31-37页

作者： Chen Baohao Cui Qimei Yang Fan National Engineering Laboratory for Mobile network Security Beijing University of Posts and Telecommunications

By virtue of an increase in spectral efficiency by reducing the transmitted pilot tones, the compressed sensing （CS） has been widely applied to pilot-aided sparse channel estimation in orthogonal frequency division multiplexing （OFDM） systems. The researches usually assume that the channel is strictly sparse and formulate the channel estimation as a standard compressed sensing problem. However, such strictly sparse assumption does not hold true in non-sample-spaced multiple channels. The authors in this article proposed a new method of compressed sensing based channel estimation in which an over-complete dictionary with a finer delay grid is applied to construct a sparse representation of the non-sample-spaced multipath channels. With the proposed, the channel estimation was formulated as the model-based CS problem and a modified model-based compressed sampling matching pursuit （CoSaMP） algorithm was applied to reconstruct the discrete-time channel impulse response （CIR）. Simulation indicates that the new method proposed here outperforms the traditional standard CS-based methods in terms of mean square error （MSE） and bit error rate （BER）.

关键词： channel estimation model-based compressed sensing non-sample-spaced multipath channels

A Frameless network Architecture for the Way Forward of C-RAN

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China Communications 2016年第6期13卷 154-166页

作者： Xiaodong Xu Zhao Sun Xun Dai Xiaofeng Tao Ping Zhang National Engineering Laboratory for Mobile network Security Beijing University of Posts and Telecommunications

The key technologies involved in the evolution of the Cloud-based Radio Access network(C-RAN) are discussed in this paper. Taking the Frameless network Architecture(FNA) as a starting point, a cell-lessbased network topology for a multi-tier Heterogeneous network(Het Net) and ultra-dense network is proposed. The FNA network topology modeling is researched with centralized processing and distributed antenna deployments. The Antenna Element(AE) is released as a new dimensional radio resource that is included in the centralized Radio Resource Management(RRM) processes. This contributes to the on-demand user-centric serving-set associations with cell-edge effect elimination. The Control Plane(CP) and User Plane(UP) separation and adaptation are introduced for energy efficiency improvements. The centralized RRM and different optimization goals are discussed for fully exploring the merits from the centralized computing of C-RAN. Considering the complexity, near-optimal approaches for specific users' Quality-of-Service(Qo S) requirements are addressed. Finally, based on the research highlighted above, the way forward of C-RAN evolution is discussed.

关键词： C-RAN frameless network architecture user-centric control plane and user plane adaptation centralized radio resource management optimization

Blockchain-based vehicular edge computing networks: the communication perspective

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Science China(Information Sciences) 2023年第7期66卷 253-265页

作者： Lin HE Fuchang LI Haikun XU Wenbo XIA Xuefei ZHANG Xiaofeng TAO Research Institute China United Network Communications Corporation Limited National Engineering Research Center of Mobile network Technologies Beijing University of Posts and Telecommunications

Vehicular edge computing(VEC) networks can satisfy the increasing demands of data processing by offloading the computation tasks to multiple distributed edge computing nodes assisted by servers. These edge servers generally combine with roadside units(RSUs). However, RSUs with edge servers cannot be fully trusted, possibly leading to serious security and privacy problems. Combining blockchain with VEC networks may establish a trusted and decentralized vehicular environment, but the coexistence of multiple communication modes comprising vehicle-to-vehicle(V2V), vehicle-to-RSU(V2R), and RSU-to-RSU(R2R) makes the block propagation patterns have different effects on the block consensus process. In this paper, we study the block propagation patterns between vehicles and RSUs with edge servers under three communication *** first give the closed-form expressions for the single-block and multiblock propagation times in two specific conditions to explore how the priority of a block generated from a specific node affects the block propagation process, in which multiblock propagation embodies competitive propagation due to blockchain ***, an innovative consensus mechanism that fully invokes the communication capability of the nodes is proposed, and the block propagation time and frequency can be substantially reduced under this *** addition, an important finding is that under the conventional and proposed consensus mechanisms, an RSU or a vehicle that creates a new block plays a decisive role in the block propagation pattern.

关键词： block propagation blockchain consensus VEC network

Stochastic Dynamic Modeling of Rain Attenuation: A Survey

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China Communications 2018年第3期15卷 220-235页

作者： Zhicheng Qu Gengxin Zhang Haotong Cao Jidong Xie College of telecommunications and Information Engineering Nanjing University of Posts and Telecommunications Satellite & Mobile communication Section Nanjing University of Posts and Telecommunications National Local Joint Engineering Research Center for communication and network technology Nanjing University of Posts and Telecommunications Key Laboratory of Broadband Wireless Communication and Sensor network Technique of Ministry of Education Nanjing University of Posts and Telecommunications

Satellite communication systems(SCS) operating on frequency bands above 10 GHz are sensitive to atmosphere physical phenomena, especially rain attenuation. To evaluate impairments in satellite performance, stochastic dynamic modeling(SDM) is considered as an effective way to predict real-time satellite channel fading caused by rain. This article carries out a survey of SDM using stochastic differential equations(SDEs) currently in the literature. Special attention is given to the different input characteristics of each model to satisfy specific local conditions. Future research directions in SDM are also suggested in this paper.

关键词： stochastic dynamic modeling rainattenuation time-series synthesizer satellitecommunication satellite link stochastic dif-ferential equations

A Two-Step Authentication Framework in Mobile Ad-Hoc networks

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China Communications 2007年第1期4卷 28-39页

作者： Nikos Komninos Dimitris Vergados Christos Douligeris Algorithms & Security Group Athens Information Technology19002 Peania Greece dept.of Information and Communication systems Engineering University of the Aegean83200 Samos Greece dept.of Informatics University of Piraeus18534 Piraeus Greece

The lack of fixed infrastructure in ad hoc networks causes nodes to rely more heavily on peer nodes for ***,establishing trust in such a distributed environment is very difficult, since it is not straightforward for a node to determine if its peer nodes can be *** additional concern in such an environment is with whether a peer node is merely relaying a message or if it is the originator of the *** this paper,we propose an authentication approach for protecting nodes in mobile ad hoc *** security requirements for protecting data link and network layers are identified and the design criteria for creating secure ad hoc networks using several authentication protocols are *** based on zero knowledge and challenge response techniques are presented and their performance is evaluated through analysis and simulation.

关键词： authentication steps link and network layers ad hoc networks