检索结果-内蒙古大学图书馆

Construction algorithms for index model based on Web page classification

Journal of Computational Information systems 2014年第2期10卷 655-664页

作者： Zhang, Yangjie Yan, Chungang Wang, Pengwei Sun, Haichun Department of Computer Science and Technology Tongji University Shanghai 201804 China The Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai 201804 China

Web pages on the Internet are massive, diverse, heterogeneous and redundant. How to organize and manage them effectively is an urgent problem. In this paper, we propose a method to index web pages and build an index model based on web page classification and hyperlink analysis. First, an initialization algorithm is given to construct an index model for an initial set of web pages. Then, considering the dynamics of web pages on the Internet, we propose an incremental updating algorithm which can update an index model incrementally. Through theoretical analysis, the complexity of proposed algorithms shows linear relationships with the scale of web pages and their growth. The experimental results show that initialization algorithm can construct an index model for a fixed number of web pages relatively fast, while the incremental updating algorithm can satisfy the update speed of web pages on the Internet. Thus, the proposed algorithms are feasible and effective. The constructed index model can provide supports for diversified information service systems to enable them to make better use of web resources and provide more valuable services to users. Copyright © 2014 Binary Information Press.

关键词： Websites

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A method to calculate recommendation trust of web services

Journal of Software Engineering

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Journal of Software Engineering 2014年第2期8卷 108-115页

作者： Liu, Wei Du, Yu-Yue Yan, Chun Sha, Jing College of Information Science and Engineering Shandong University of Science and Technology Qingdao China The Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai China

Web services are widely accepted and used in the e-commerce. Trust plays an important role in selecting one Web service for application among many services satisfying the demand of requesters and trust for Web services is a hot topic in research fields. This study proposes a method to calculate recommendation trust of Web services and the weight of every recommender is confirmed by norm grey correlation analysis method. The detailed process of the given method is revealed by a specific instance. The method avoids the vicious recommendation and improves the reliability of selected services. © 2014 Academic Journals Inc.

关键词： Web services

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Iterative grouping calibration for channel reciprocity in TDD MU-MIMO systems

Iterative grouping calibration for channel reciprocity in TD...

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International Conference on Communications and Networking in China (CHINACOM)

作者： Qiang Liu Xin Su Jie Zeng Tiejun Lv Hui Gao 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)9781479987962

In this paper, we propose a new iterative grouping calibration algorithm for channel reciprocity in MU-MIMO (multiuser multiple-input multiple-output) systems. We assume the system operate in Time-division duplex (TDD). Because the TDD channel is reciprocal, we can use the uplink channel to estimate the downlink channel. The free-space electromagnetic channel can be regard as reciprocal channel in TDD channel. However, the generalized channel do not only consist of free-space electromagnetic channel, but also include transceiver circuitry. And in general case, the transceiver circuitry isn't perfect. For that reason, the reciprocity of generalized channel is destroyed. In this paper, we set a base station with one antenna to be the reference user, then we divide the MIMO BS antennas into N groups. We assume the users and every antenna group reform a new user-antenna group, the scope of transceiver circuitry coherence time in different user-antenna group are different. We only calibrate one user-antenna group in one free-space electromagnetic channel coherence time. The iterative grouping calibration algorithm in this paper can improve the channel capacity by transmitting pilot and signal at the same time slot. And the iterative grouping calibration algorithm goes especially well with massive mimo systems and high-speed mobile environment for its flexible antenna grouping.

关键词： Calibration Antennas Transceivers Coherence MIMO Downlink Electromagnetics

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An improved relative channel reciprocity calibration method in TDD massive MIMO systems

An improved relative channel reciprocity calibration method ...

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International Conference on Wireless and Optical Communications ( WOCC)

作者： Qiang Liu Xin Su Jie Zeng Hui Gao Tiejun Lv Xibin Xu Chiyang Xiao Tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing China Key Laboratory of Trustworthy Distributed Computing and Service Beijing University of Posts and Telecommunications Beijing China

In this paper, we introduce an improved relative channel reciprocity calibration method in TDD massive multiple-input multiple-output (MIMO) systems. The improved calibration method divide the massive MIMO system into one Single-Input Single-Output (SISO) system and two Single-Input Multiple-Output (SIMO) systems instead of calibrating the massive MIMO directly. We select the channel with high channel gain to be the reference channel (the SISO system), the antennas of the SISO system are the reference antennas. At the same station the reference antenna and the other antennas consist the SIMO system. The three systems include all the receive circuitry and the transmit circuitry information of the massive MIMO system. We calibrate the three systems and acquire the calibration coefficients. Then we use the calibration coefficients of the three systems to calibrate the massive MIMO system. The proposed calibration method in this paper can reduce the amount of feedback and the computation complexity compared with calibrating the massive MIMO directly. What's more, the improved calibration method outperforms the traditional calibration method under high-speed mobile environment.

关键词： Calibration MIMO Downlink Uplink Radio transmitters Transmitting antennas

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An optimized Apriori algorithm based on sparse matrix for intrusion detection

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Open Cybernetics and systemics Journal 2014年第1期8卷 8-11页

作者： Zeng, Xiaohui Lv, Jingxiang Li, Jingzhong Luo, Wenlang Dept. of Computer Science and Technology Jinggangshan University Ji’an China The Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai China

The original Apriori algorithm is widely used in the intrusion detection field, but it may consume incredible computing resources in the process of handling network packets. We propose our optimized-Apriori algorithm which can greatly improves the algorithm efficiency by means of reducing the data storage space and the number of frequent item sets. We take full advantage of the characteristics of sparse matrix to save storage space and shorten the running time. The experimental results show that our optimized-Apriori algorithm can make a larger progress in saving the storage space of network data to be processed, even shortening nearly half of the data mining time in the process of intrusion detection. © Zeng et al.

关键词： Data mining

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Autonomic Performance and Power Control on Virtualized Servers:Survey, Practices, and Trends

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Journal of Computer Science & technology 2014年第4期29卷 631-645页

作者：周笑波蒋昌俊 IEEE ACM Department of Computer Science University of Colorado Colorado Springs U.S.A. The Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University CCF Department of Computer Science and Technology Tongji University

Modern datacenter servers hosting popular Internet services face significant and multi-facet challenges in performance and power control. The user-perceived performance is the result of a complex interaction of complex workloads in a very complex underlying system. Highly dynamic and bursty workloads of Internet services fluctuate over multiple time scales, which has a significant impact on processing and power demands of datacenter servers. High-density servers apply virtualization technology for capacity planning and system manageability. Such virtuMized computer systems are increasingly large and complex. This paper surveys representative approaches to autonomic performance and power control on virtualized servers, which control the quality of service provided by virtualized resources, improve the energy efficiency of the underlying system, and reduce the burden of complex system management from human operators. It then presents three designed self-adaptive resource management techniques based on machine learning and control for percentile-based response time assurance, non-intrusive energy-efficient performance isolation, and joint performance and power guarantee on virtualized servers. The techniques were implemented and evaluated in a testbed of virtualized servers hosting benchmark applications. Finally, two research trends are identified and discussed for sustainable cloud computing in green datacenters.

关键词： autonomic computing joint performance and power control virtualized server Internet application sustainable computing

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Noncoherent detection of satellite-based AIS signal with phase offset compensation

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Sensors and Transducers 2014年第3期166卷 128-134页

作者： Ma, Shexiang Fang, Ting Key Laboratory of Computer Vision and System Ministry of Education Tianjin University of Technology Tianjin China Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology Tianjin University of Technology Tianjin China

Considering the existence of large Doppler frequency shift, fast time-varying channels and multiple user interference and other serious problems in the satellite-based AIS system, a noncoherent detection method called phase adaptive algorithm is proposed. For AIS signals, utilizing the characteristic of the energy distribution under the Laurent decomposition of PAM waveform, matched filter is evaluated without whitening filter on the main component. This can effectively avoid the influence of the correlation length on the performance of detection. And the complexity of the system is significantly reduced. The cost function of decoding is given based on maximum likelihood criterion in the algorithm. Multiple symbols as the observation window are decoded at the same time. Meanwhile, phase adaptive compensation is employed in the decoding process. Simulation results show that this method has good detection performance. The BER is close to the ideal coherent detection when the size of observation window is 10 symbols, and is superior to the traditional differential decoding. At the same time, the algorithm has a higher robust and is also applicable to the conditions of multiple user co-channel interference. © 2014 IFSA Publishing, S. L.

关键词： Satellites

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Data streams classification method handling concept drifts

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Journal of Information and Computational Science 2014年第15期11卷 5427-5435页

作者： Wang, Xiaoye Hao, Yapei Zhang, Tao Chen, Bingjie Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology Tianjin University of Technology Tianjin China Key Laboratory of Computer Vision and System Ministry of Education Tianjin University of Technology Tianjin China

This paper presented a classification algorithm which could find the concept drifts from the data streams, called Incremental Updated Discriminant Eigenspace (IUDE). The algorithm constructs the eigenspace model of the data streams based on the algorithm of LDA (linear discriminant analysis). It handles the Gradual Concept Drifts by incremental update the Discriminant eigenspace. And at the same times, it uses the Mean Square Error (MSE) to handle the Abrupt Concept Drifts. The 1-nearest neighbour (1-NN) method classifies the new data streams. The experiment result shows that it is better flexibility over concept drifts than traditional approaches. Copyright © 2014 Binary Information Press.

关键词： Mean square error

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SAR image compression and reconstruction based on Compressed Sensing

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Journal of Information and Computational Science 2014年第2期11卷 573-579页

作者： Guo, Lina Wen, Xianbin Key Laboratory of Computer Vision and System of Ministry of Education Tianjin University of Technology Tianjin 300191 China Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology Tianjin 300191 China

The appearance of multiplicative speckle noise in Synthetic Aperture Radar (SAR) imagery makes it very difficult to visualization and compression. This paper proposes a novel framework of Compressed Sensing (CS) to compress the SAR image. It combined the Nonsubsampled Contourlet Transform (NSCT) shrinkage method to SAR image sparse represent. And a modified Smoothed LO norm (SLO) algorithm is used for SAR image accurate reconstruction. The experimental results show the proposed method is very effective and can get better reconstruction performances. Copyright © 2014 Binary Information Press.

关键词： Compressed sensing

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AAA Based on 802.1x Authentication

AAA Based on 802.1x Authentication

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2015 Joint International Mechanical,Electronic and Information technology Conference(JIMET 2015)

作者： Jiange Zhang Yuanbo Guo Yue Chen Jun Ma State Key Laboratory of Mathematical Engineering and Advanced Computing China National Digital Switching System Engineering and Technological Research CenterZhengzhou Information Science and Technology Institute

ISBN: (纸本)9781510817982

It has obvious advantage to adopt 802.1x authentication for network access control, which is an ideal and low-cost scheme and is usually used for those enterprises and campuses which run and manage simply or have simple business. This paper analyzed 802.1x protocol, EAP protocol and RADIUS protocol, configured switch, Free RADIUS Server and My SQL, constructed AAA management framework which is based on 802.1x authentication at the end, and showed the whole authentication flow. Using software the messages of the whole authentication process have been captured. The brief analysis of these messages provides technology strongly for particular research and further improvement, and has important value for research and application.

关键词： 802.1x authentication EAP protocol RADIUS protocol configure analysis of these messages

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