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International Conference on Advances in Social Network Analysis and Mining, ASONAM

作者： Ying Wen Yuanhao Chen Xiaolong Deng International School Beijing University of Posts and Telecommunications China Key Laboratory of Trustworthy Distributed Computing and Service Beijing University of Posts and Telecommunications China

Community detection in inhomogeneous structured network is an attractive research problem that searches for methods to discover groups in which individuals are more densely interconnected with each other with higher probability of internal information propagation. While most of the previous approaches attempt to divide networks into communities according to the algorithm results of network or edge measurement, Label Propagation Algorithm (LPA) adopts semi-supervised machine learning and implements community detection in an intelligent way with the automatic convergent process of network entity label iteration. In this work, we study the early community detection approaches, explore the low efficacy and stagnant converging rate of LPA in its response to network with overlapped communities, and propose a new approach for community detection using epidemic spreading virus to discover groups with super positioned members. Extensive experiments in synthetic signed network and real-life large networks derived from Internet social media are conducted to explore the optimal mechanism of the most suitable community-detecting virus infection.

关键词： Communities Social network services Kernel Media Mathematical model Educational institutions Conferences

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Achievable sum rate analysis of ZF receivers in 3D MIMO with Rayleigh/log-normal fading channels

Achievable sum rate analysis of ZF receivers in 3D MIMO with...

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IEEE Globecom Workshops

作者： Fangqing Tan Hui Gao Tiejun Lv Jie Zeng Key Laboratory of Trustworthy Distributed Computing and Service Beijing University of Posts and Telecommunications Beijing China Tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing China

ISBN: (纸本)9781479974719

Three dimensions multiple-input multiple-output (3D MIMO) system is now gaining a growing interest among researchers in wireless communication, the reason can be attributed to its potential to enable a variety of strategies like user specific 3D beamforming and cell-splitting. In this paper, we pursue the performance evaluation of 3D MIMO system employing zero-forcing (ZF) receivers, accounting for both large and small-scale fading. In particular, we consider the classical log-normal model and antenna gain with tilting angle, we derive the optimal tilting angle for 3D MIMO system which maximizes the sum rate, furthermore, based on the optimal tilting angle, we propose a closed-form linear approximation on the achievable sum rate in the asymptotically high signal-to-noise ratio (SNR) and low-SNR regime, respectively. We investigate the effect of antenna tilting angle, number of base station (BS) antennas and the distance between BS and the center of building on the achievable sum rate performance of 3D MIMO.

关键词： MIMO Three-dimensional displays Fading Antennas Receivers Signal to noise ratio Linear approximation

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A method based on MD5 and time for preventing deception in electronic commerce

A method based on MD5 and time for preventing deception in e...

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International Conference on Cyberspace Technology (CCT 2014)

作者： Zhenggang Hu Yueming Lu School of Information and Communication Engineering Beijing University of Posts and Telecommunications China Key Laboratory of Trustworthy Distributed Computing and Service (BUPT) Ministry of Education Beijing China

ISBN: (纸本)9781510802704

Aiming at reducing the risk of data being intercepted and preventing deceptions in the electronic commerce, this paper proposes a method based on MD5 and time which can effectively prevent the deception in data transmission. The method uses the traditional MD5 algorithm to encrypt and validate important data, then verifying the validity and legitimacy of the data by using time.

关键词： electronic commerce md5 algorithm preventing deception time electronic commerce MD5 MD5 algorithm Deception data transmission Legitimacy

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Detecting the run time attacks in the cloud with an evidence collection based approach

Detecting the run time attacks in the cloud with an evidence...

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IEEE International Conference on Cloud computing and Intelligence Systems (CCIS)

作者： Jie Lin Chuanyi Liu Zhichun Ning Binxing Fang School of Computer Science Beijing University of Posts and Telecommunications Beijing China Ministry of Education Key Laboratory of Trustworthy Distributed Computing and Service (BUPT) Beijing China

ISBN: (纸本)9781467369541

As the impacts of security threats are amplified and spread quickly in the cloud, especially with the attribute of large-scale virtualization. Most of researches focus on monitoring the network traffic. However, these methods don't check how the attack happened and what damage the attack caused for the virtual infrastructure. This paper presents a logging method to analyze the potential attacks out of VM and a prototype was implemented. The experimental results show that this method can detect the real world attacks effectively and the performance overhead is acceptable.

关键词： Monitoring Software Servers Virtualization Virtual machining Binary codes Computer architecture

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Low-Complexity User Scheduling in the Downlink Massive MU-MIMO System with Linear Precoding

Low-Complexity User Scheduling in the Downlink Massive MU-MI...

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IEEE/CIC International Conference on Communications in China

作者： Ou Bai Hui Gao Tiejun Lv Chau Yuen Key Laboratory of Trustworthy Distributed Computing and Service Ministry of Education School of Information and Communication Engineering Beijing University of Posts and Telecommunications Singapore University of Technology and Design

ISBN: (纸本)9781479941452

In this paper, we investigate low-complexity user scheduling schemes for the downlink (DL) massive multiuser multiple-input multiple-output (MU-MIMO) system, where an M-antenna (M is very large) base station (BS) serves K (K > 2) N-antenna (N > 1) users with linear transceivers. Establishing the theoretical foundation of our scheduling schemes, we first investigate the asymptotic sum-rates of this system with both singular value decomposition (SVD) and regularized zero-forcing (RZF) precoders. In particular, we assume that both M and N go to infinity with a bounded ratio to perform the theoretical derivations with random matrix theory (RMT). In addition, the influence of imperfect channel estimation is also considered. Interestingly, the analysis indicates the existence of an optimal number of served users K~* in terms of asymptotic sum-rate, which motivates our low complexity user scheduling schemes. Unlike the conventional schemes with complicated computations and instantaneous channel state information, our user scheduling schemes are based on semi-analytical solutions with only statistic CSI. Simulation results validate our theoretical derivations and show the advantages of our schemes in the massive MU-MIMO system.

关键词： MIMO communication computational complexity precoding singular value decomposition telecommunication scheduling MU-MIMO system SVD decoder asymptotic sum-rate channel estimation channel state information downlink massive MU-MIMO system downlink massive multiuser multiple-input multiple-output system linear precoding linear transceivers low-complexity user scheduling scheme random matrix theory semianalytical solutions Antennas MIMO Processor scheduling Resource management Signal processing Vectors Wireless communication

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Multi-features based classification for automatic summarization

Multi-features based classification for automatic summarizat...

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International Conference on Multimedia, Communication and computing Application（MCCA 2014）

作者： H.Y.Li R.F.Liu W.R.Xu R.S.Shi School of Information and Communication Engineering Beijing University of Posts and Telecommunication Education Ministry Key Laboratory of Trustworthy Distributed Computing and Service BUPT School of HumanitiesBUPT

That the summary of an article can be automatically generated is an important text processing *** technique can automatically extract the most useful information of the text and present that information,which makes it easy to navigate and judge the importance to *** paper is based on a variety of texts and structure *** vector-machine classification method is used to identify summary sentences,which abandoned the traditional experience weight setting to *** effective system that combines keywords density and document structure with the best weights is implemented for automatic *** experimental results show that our Density and Structure Based Summary system improves the automatic summarization ***'s better than the other two systems and has a big promotion on the precision,recall and F score.

关键词： Multi-features based classification for automatic summarization

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Bit allocation for quality scalability coding of H.264/SVC

Bit allocation for quality scalability coding of H.264/SVC

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IEEE Conference on Advanced Video and Signal Based Surveillance (AVSS)

作者： Wang Bo Li Teng Songlin Sun Xiaojun Jing Hai Huang School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing China Key Laboratory of Trustworthy Distributed Computing and Service (BUPT) Ministry of Education Beijing China

An efficient model-based bit allocation algorithm, in this paper, is proposed for quality scalability coding of H.264/scalable video coding (SVC). The conventional Rate-Distortion models are not available for quality scalability coding of H.264/SVC. To overcome this issue, the relationship between the percentage of header bits and quantization parameter is investigated to obtain an accurate single layer rate model. Moreover, MGS/CGS inter-layer MAD affine relationship is employed to extend the Rate-Distortion models from the base layer (BL) to the enhancement layer (EL). Finally the Lagrange solution of the bit allocation problem is worked out. Experimental results show that the proposed bit allocation algorithm outperforms Joint Scalable Video Model (JSVM) software algorithm.

关键词： Bit rate Encoding Quantization (signal) Static VAr compensators Scalability Software algorithms Signal to noise ratio

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Beamforming for Secure Two-Way Relay Networks with Physical Layer Network Coding

Beamforming for Secure Two-Way Relay Networks with Physical ...

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IEEE Global Communications Conference

作者： Cong Zhang Hui Gao Tiejun Lv Yueming Lu Xin Su Key Laboratory of Trustworthy Distributed Computing and Service Ministry of Education School of Information and Communication Engineering Beijing University of Posts and Telecommunications Tsinghua National Laboratory for Information Science and Technology Tsinghua University

ISBN: (纸本)9781479935130

We investigate the secrecy beamforming in two-way relay channels (TWRC) with physical layer network coding (PNC). The multi-antenna relay broadcasts the superimposed signal of two user messages with secrecy beamforming after receiving the signals transmitted by the two legitimate users. We first propose a lower bound of the secrecy sum rate to quantify the secrecy performance of the TWRC with PNC. Because the maximization of the lower bound is non-convex under total power constraint, we propose a joint beamforming and power allocation scheme, in which the problem is successively approximated by several convex semidefinite programs. In order to reduce the complexity, we further propose an suboptimal scheme with closed-form solution. Numerical results indicate that the proposed schemes with PNC achieve much better secrecy sum-rate performance than the traditional AF schemes.

关键词： array signal processing network coding optimisation relay networks (telecommunication) TWRC convex semidefinite programs joint beamforming and multiantenna relay broadcasts physical layer network coding power allocation scheme secrecy beamforming suboptimal scheme two-way relay channels two-way relay networks Approximation methods Array signal processing Optimization Protocols Relays Resource management Vectors

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Sybil detection and analysis of micro-blog Sina

Sybil detection and analysis of micro-blog Sina

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2014 International Conference on Informatics, Networking and Intelligent computing(INIC 2014)

作者： R.F.Liu Y.J.Zhao R.S.Shi School of Information and Communication Engineering Beijing University of Posts and Telecommunication Education Ministry Key Laboratory of Trustworthy Distributed Computing and Service School of HumanitiesBeijing University of Posts and Telecommunication

There are some Sybil accounts on Sina *** this paper,we comprehensively analyse their features,and the reasons for their *** believe there are three levels of Sybil accounts,original Sybil,improved Sybil,and advanced *** of the Sybils are original Sybil accounts.A Self-organizing Map(SOM) is used to identify the original Sybils,and a manually verified dataset is used to train the SOM network,and test the efficiency of the ***,for the improved and advanced Sybil accounts,the content of tweets and comments can be used to detect *** are some rules which are defined which mark a Sybil account according to the user's posted *** order to verify our analysis and detection methods,we crawl500 thousand users' information from Sina *** experiment results show that the content based detection method has high *** combination of the SOM model and the content based detection method can increase the precision and recall of the results at the same *** the best of our knowledge,this is the first study to comprehensively analyse and detect Sybil accounts of Sina Weibo.

关键词： Sybil detection and analysis of micro-blog Sina

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Decision-feedback multiple symbol detection for differential space-time block coded UWB systems

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Science China(Information Sciences) 2013年第4期56卷 50-59页

作者： LV TieJun WANG TaoTao GAO Hui Key Laboratory of Trustworthy Distributed Computing and Service Ministry of EducationBeijing University of Posts and Telecommunications Department of Information Engineering The Chinese University of Hong Kong

The symbol-by-symbol differential detection scheme,originally employed to detect differential spacetime block coded(DSTBC) ultra-wideband(UWB) signal in previous work,su?ers from a performance degradation compared with coherent *** this paper,a noncoherent multiple symbol detection(MSD) scheme is proposed to enhance the performance of DSTBC-UWB *** the signal model of DSTBC-UWB is analyzed,the optimal maximum likelihood(ML) MSD is derived and then a suboptimal ML-MSD is obtained by channel ***,exhaustive search based MSD is impractical in DSTBC-UWB systems since its complexity increases exponentially with observation window *** decrease the computational complexity,the decision-feedback(DF) scheme is introduced to *** resultant DF-MSD yields reasonable complexity and solid performance improvement.

关键词： ultra-wideband(UWB) space-time block code(STBC) differential detection multiple symbol detection(MSD)

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