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Structural Modeling and Characteristics Analysis of Flow Interaction networks in the Internet

Chinese Physics Letters 2015年第6期32卷 204-207页

作者：武晓宇顾仁涛潘卓娅金伟祺纪越峰 Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

Applying network duality and elastic mechanics, we investigate the interactions among Internet flows by con- structing a weighted undirected network, where the vertices and the edges represent the flows and the mutual dependence between flows, respectively. Based on the obtained flow interaction network, we find the existence of ＇super flow＇ in the Internet, indicating that some flows have a great impact on a huge number of other flows; moreover, one flow can spread its influence to another through a limited quantity of flows （less than 5 in the experimental simulations）, which shows strong small-world characteristics like the social network. To reflect the flow interactions in the physical network congestion evaluation, the ＇congestion coefficient＇ is proposed as a new metric which shows a finer observation on congestion than the eonventional one.

关键词： POLYMER networks ELASTIC analysis (Engineering) INTERNET content INTERNET domain names network analysis (Social sciences)

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A QoS-based multi-rate multicast scheme over heterogeneous cellular network

A QoS-based multi-rate multicast scheme over heterogeneous c...

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International Symposium on Wireless Communication systems (ISWCS)

作者： Tang Liu Hailun Xia Chunyan Feng Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781509020621

Wireless multimedia traffic has increased considerably in recent years, which puts forward higher demand on the capacity of existing network. Multicast, as a transmission strategy with high spectral efficiency, has not been widely studied in heterogeneous cellular network (HetNet). In this paper, we propose a QoS-based multi-rate multicast scheme over HetNet to effectively improve the system throughput while guaranteeing the quality of service (QoS) of the whole system. We formulate an expression of system throughput of the proposed multicast scheme and decouple it into three subproblems for its computational complexity, namely, user association (UA), subgroup formation (SF) and resource allocation (RA). In UA, we present a traffic-oriented access method based on reference signal receiving power (RSRP). In SF, the associated users are divided into several subgroups according to their channel state information (CSI) and the users in one subgroup are served with the same rate determinated by the CSI level of the subgroup. In RA, fractional frequency reuse (FFR) mechanism is used to eliminate the co-channel cross-tier interference between macro base station (MBS) and small base stations (SBS). And QoS is considered both in subcarrier allocation and power allocation processes. Simulation results show that the system throughput is significantly improved while QoS is guaranteed by using our scheme.

关键词： Resource management Quality of service Throughput Interference Computational complexity Base stations Wireless communication

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Modified Bayesian Inference for Trajectory Prediction of network Virtual Identity Based on Spark

Modified Bayesian Inference for Trajectory Prediction of Net...

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International Conference on Intelligent Human-Machine systems and Cybernetics, IHMSC

作者： Yuhang Song Gang He Dechen Yu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781509007691

Traditional trajectory prediction method shows low prediction accuracy when dealing with a limited number of historical trajectory. Therefore an improved Bayesian inference (MBI) method is proposed, which builds a Markov model to quantify the correlation between adjacent locations, and provides a more accurate Markov model by decomposing the historical trajectory. Finally we improve Bayesian inference formula. The experiment uses Spark platform processing original data and intermediating results of calculations as the large amount of data to be calculated. The results show that, MBI method is 2-3 times faster than the speed of existing prediction methods, and has higher accuracy and stability. MBI method makes full use of existing track information, not only to improve the query efficiency, but also to ensure a higher prediction accuracy.

关键词： Trajectory Sparks Markov processes Bayes methods Databases History

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WoT/SDN:Web of Things architecture Using SDN

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China Communications 2015年第11期12卷 177-187页

作者： QIU Xiaofeng LIU Wenmao GAO Teng HE Xinxin WEN Xutao CHEN Pengcheng Beijing Key Laboratory of Network System Architecture and Convergence BUPT NSFocus Security Labs

Wo T(Web of Things) integrates smart devices into Web by reusing and extending Web standards. While Web technology makes the developers' job easier,it faces security,management and efficiency challenges. We propose Wo T/SDN,the architecture of resource oriented Wo T built on SDN(Software Defined network),in which applications could be developed through resource subscription and Mashup with the programmability provided by SDN. The key components are designed,including Security and Management Controller(SMC),various atomic services and resource subscription syntax. Three applications covering device management,data access and security protection are demonstrated. Compared to traditional resource-oriented Wo T systems,our test results show that SDN,with its logically centralized control capability and awareness of flow forwarding,provides new opportunity to improve performance,simplify management and enhance security for Wo T.

关键词： Wo T SDN Controller

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network traffic and user behavior analysis of mobile reading applications

Network traffic and user behavior analysis of mobile reading...

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International Conference on Information Science and Technology (ICIST)

作者： Yue Chang Fang Liu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

Mobile reading ranks No.4 on the permeate proportion of the mobile Internet applications and is increasing gradually. Understanding user behaviors of mobile reading is important for service provider. However, few work has been done on reading analysis. In this paper, we provide an approach to solve this problem based on cloud computing platform including HDFS and Apache Pig. Our study is carried out based on the data collected from the ISP network which covered an entire city in southern China. We presented the feature of traffic and behavior in three aspects. First, we compared the service condition of several popular websites in mobile reading field and found the basic law that traffic distribution fits. Second, we recognize user sessions via time threshold method and found some interesting phenomenon about session duration. Finally, we break user actions down into discrete categories and summarized the characteristics of each reading application. We compared user acceptance of different applications from three perspectives, which are user loyalty, user behavior and cross-user distribution respectively.

关键词： Decision support systems Time-frequency analysis

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Large-scale characterization of comprehensive online video service in mobile network

Large-scale characterization of comprehensive online video s...

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IEEE International Conference on Communications (ICC)

作者： Chenyu Li Jun Liu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781479966653

Video service in mobile network generates massive Internet traffic and consumes a large share of bandwidth. Nowadays, more and more video portals have upgraded their service to a comprehensive one-stop solution, providing UGC, VoD and Live streaming at the same time. Understanding the characteristics of such service is crucial for the network traffic engineering and the sustainable development of service. In this paper we present the first characterization work in mobile network on a leading comprehensive online video service in China, Youku. Our study is based on large-scale datasets containing 16 billion network traffic traces and long-term crawling data (over 1 month). We examine the user activity in both temporal and spacial dimensions and reveal the relatively fixed service usage. We demonstrate the strong correlations between users, which is reflected by the small-world phenomenon. We also investigate the static properties of Youku mobile videos and observe noticeably differences from other UGC videos. Eventually, we study the distribution of view count and find out four growth patterns for the new published videos. Our analysis result provides a insight into how Youku is utilized by mobile users and demonstrates promising practical applications for both network operators and service providers.

关键词： Streaming media Mobile communication Mobile computing Switches YouTube Internet Entropy

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Where do you watch? A spatial analysis of online video service in mobile network

Where do you watch? A spatial analysis of online video servi...

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International Symposium on Wireless Personal Multimedia Communications (WPMC)

作者： Chenyu Li Jun Liu Shuxin Ouyang Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781509053773

We present a specialized characterization work in the spatial dimension of online video service in mobile network. A better understanding of the spatial characteristics of such service is a key capability for network operators and service providers, but remains an unsolved problem. It is extremely challenging because the complexity to get the location information of the mobile users. In this paper, we address this problem head on by collecting a large-scale dataset containing over 9 billion network traffic traces from a cellular network in a north-eastern city in China. We further extract the video requests from those data. The user location information is cast into the information of cells visited by the users in the cellular network when they watch mobile videos. Based on this dataset, we provide a comprehensive characterization of the online video service in mobile network in the spatial dimension: 1) The overall geographic distribution of video requests is uncovered and hot spot regions are discovered. And the video request location entropy is defined to analyze how request time and video category impact the overall geographic distribution. 2) Then, the user mobility pattern is defined in terms of cell sequence and residence time. The movement of each mobile user while watching videos in mobile network and the overlapping of request locations between different sessions and different days of each user are further studied. 3) At last, the video request spatial distribution of each video is analyzed. The linear relationship between the video request spatial distribution and the video popularity is uncovered. In addition, the categories and user mobility patterns for the widely watched videos are analyzed. To the best of our knowledge, this is the first specialized study to shed light on the online video service in mobile network from the spatial angle. Our analysis provides a unique insight into how Youku is utilized by mobile users. We believe our observation find

关键词： Mobile computing Streaming media YouTube Cellular networks Urban areas Entropy

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Adaptive weighted fuzzy clustering algorithm for load profiling of smart grid customers

Adaptive weighted fuzzy clustering algorithm for load profil...

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IEEE International Conference on Communications in China (ICCC)

作者： Yun Lu Tiankui Zhang Zhimin Zeng Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

With the rapid development of the smart grid, a large volume of smart meter data are collected in the form of time series, which is called load profiles. This paper investigates the load profile clustering of smart grid customers, which is significant for many applications. An adaptive weighted fuzzy clustering algorithm is proposed to cluster load profiles, where Principle Component Analysis (PCA) is used to reduce the data dimension, and then weighted Fuzzy C-Means (FCM) is adopted to cluster the big data. The optimal number of clusters is determined adaptively by integrating a clustering validity function into the clustering algorithm. The simulation results show that the proposed algorithm could achieve considerable improvement both in time complexity and clustering accuracy through comparing four clustering validity indexes.

关键词： Clustering algorithms Principal component analysis Partitioning algorithms Algorithm design and analysis Indexes Smart grids Smart meters

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An adaptive polarization-QAM modulation scheme for improving the power amplifier energy efficiency in OFDM systems

An adaptive polarization-QAM modulation scheme for improving...

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IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： Shulun Zhao Zhimin Zeng Chunyan Feng Fangfang Liu Yao Nie Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781509032556

To improve the energy efficiency of power amplifier in OFDM systems, an adaptive polarization-QAM modulation scheme is proposed considering the data rate requirement variation at the transmitter. Since QAM and polarization modulation have different energy efficiency performance in the linear and nonlinear region of power amplifier respectively, thus the optimal energy efficiency can be obtained by combining the two modulation schemes together and adjusting their modulation order adaptively to fulfill the varying data rate requirement. The power series model of power amplifier is used to analyze the effects of both the in-band distortions and the out-of-band emissions on OFDM signals. Based on above, the proposed scheme can be formulated as an optimization problem regarding the output back off value as well as the modulation order of polarization modulation and QAM. Simulations under the same symbol error rate threshold and data rate requirement show that, the energy efficiency of the proposed scheme is nearly twice as that of the traditional QAM scheme in OFDM systems.

关键词： OFDM Quadrature amplitude modulation Adaptation models Nonlinear distortion Data models

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Exploiting polarization to resist phase noise for digital self-interference cancellation in full-duplex

Exploiting polarization to resist phase noise for digital se...

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IEEE International Conference on Communications (ICC)

作者： Fangfang Liu Songlin Jia Caili Guo Chunyan Feng Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

Phase noise caused by the unideal local oscillators limits the self-interference cancellation performance severely in full-duplex systems. In this paper, a novel digital polarization self-interference cancellation method is proposed to break the bottleneck of phase noise. The basic idea here is that the polarization is insensitive to the absolute phase and will not be affected by the random phase noise. Without any prior knowledge of the phase noise, the proposed method exploits the polarization signal processing to transform the multiplicative phase noise to a new additive white Gaussian noise, which benefits from the vectorial property of polarization. Based on the polarization system and signal models with the phase noises both in the upconversion and the downconversion, we demonstrate that the self-interference can be cancelled by regeneration where only a transformed additive white Gaussian noise exists. Moreover, the proposed method obtains an upper bound for digital self-interference cancellation when the phase noise exists if the dual-polarized channel estimation is perfect. The simulation is conducted in advanced design system, and results show that the proposed method cancels the self-interference to noise floor.

关键词： Phase noise Baseband Local oscillators Interference Receivers Additive noise

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