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A New ETL Approach Based on Data Virtualization

Journal of computer Science & Technology 2015年第2期30卷 311-323页

作者：郭树盛袁子牧孙傲冰岳强 State Key Laboratory of Computer System and Architecture Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100190 China Cloud Computing Center Chinese Academy of Sciences Dongguan 523808 China

ETL （Extract-Transform-Load） usually includes three phases： extraction, transformation, and loading. In building data warehouse, it plays the role of data injection and is the most time-consuming activity. Thus it is necessary to improve the performance of ETL. In this paper, a new ETL approach, TEL （Transform-Extract-Load） is proposed. The TEL approach applies virtual tables to realize the transformation stage before extraction stage and loading stage, without data staging area or staging database which stores raw data extracted from each of the disparate source data systems. The TEL approach reduces the data transmission load, and improves the performance of query from access layers. Experimental results based on our proposed benchmarks show that the TEL approach is feasible and practical.

关键词： cloud computing big data ETL heterogeneous database data virtualization

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Optimizing Parallel Kinetic Monte Carlo Simulation by Communication Aggregation and Scheduling

Optimizing Parallel Kinetic Monte Carlo Simulation by Commun...

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2015大数据技术及应用论坛

作者： Baodong Wu Shigang Li Yunquan Zhang State Key Laboratory of Computer System and Architecture Institute of Computing TechnologyChinese Academy of Sciences

Kinetic Monte Carlo(KMC) algorithm has been widely applied for simulation of radiation damage, grain growth and chemical reactions. To simulate at a large temporal and spatial scale, domain decomposition is commonly used to parallelize the KMC algorithm. However, through experimental analysis, we find that the communication overhead is the main bottleneck which affects the overall performance and limits the scalability of parallel KMC algorithm on large-scale clusters. To alleviate the above problems, we present a communication aggrega‐tion approach to reduce the total number of messages and eliminate the commu‐nication redundancy, and further utilize neighborhood collective operations to optimize the communication scheduling. Experimental results show that the opti‐mized KMC algorithm exhibits better performance and scalability compared with the well-known open-source library—SPPARKS. On 32-node Xeon E5-2680 cluster(total 640 cores), the optimized algorithm reduces the total execution time by 16 %, reduces the communication time by 50 % on average, and achieves 24 times speedup over the single node(20 cores) execution.

关键词： Domain decomposition Communication aggregation Communication scheduling Neighborhood collectives

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Improved recommendation system using friend relationship in SNS 19th

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19th International Conference on Transactions on Computational Collective Intelligence, TCCI 2015

作者： Liao, Qing Wang, Bin Ling, Yanxiang Zhao, Jingling Qiu, Xinyue School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing100876 China School of Computer Science Beijing University of Posts and Telecommunications Beijing100876 China Beijing Key Laboratory of Network System Architecture and Convergence Beijing100876 China

ISBN: (纸本)9783662490167

With the rapid development of the Internet, SNS services and 3G commercial mobile applications there have been tremendous opportunities although the development of SNS is very short in China, and the social web game is in the early stage of development. Because of massive users, the potential commercial value of Chinese SNS is still a great mining space. However, a relatively large defects is the precipitation and accumulation on content. The dynamic of friends will affect our own decisions largely, it is favorable for the activity of SNS to increase the number of friends. We have improved the existing models, and conduct experiments to validate it and compare it with previous methods. © Springer-Verlag Berlin Heidelberg 2015.

关键词： Social networking (online)

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Performance Study of Relay Coordination Schemes for Two-Hop Networks: Two-Cell Case

Performance Study of Relay Coordination Schemes for Two-Hop ...

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IEEE International Conference on Communications

作者： Kasun T. Hemachandra Norman C. Beaulieu Department of Electrical and Computer Engineering University of Alberta School of Information and Communication Engineering and the Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

ISBN: (纸本)9781467364300

The outage probability of a two-hop coordinated decode-and-forward relay network is investigated. Relay coordination is performed only with the dominant interferer. Different levels of network coordination are studied and their performances are compared. Exact expressions are derived for the outage probability of a particular mobile user for each coordination scheme. Asymptotic outage probability is derived to identify the diversity and coding gains for each coordination scheme.

关键词： Cochannel interference Decode-and-forward Outage probability Relay coordination Zero-forcing

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Performance Analysis of DF Relaying with Optimum Combining in a Poisson Field of Interferers

Performance Analysis of DF Relaying with Optimum Combining i...

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IEEE International Conference on Communications

作者： Navod Suraweera Norman C. Beaulieu Department of Electrical and Computer Engineering University of Alberta School of Information and Communication Engineering and Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecomunications (BUPT)

ISBN: (纸本)9781467364300

The performance of optimum combining (OC) in decode-and forward (DF) relaying in the presence of a Poisson field of interferers is analyzed. An approximation for the outage probability of the OC receiver is derived by considering the temporal correlation of the interference. Despite the randomness of the number and the locations of the interferers, the OC receiver suppresses the interference at the destination node and diversity gains are achieved, provided that the relay nodes are noise limited. For single-antenna relay nodes, the end-to-end performance is vulnerable to interference at the relay nodes which is not canceled, resulting in zero diversity gains.

关键词： DF relaying Interference Optimum combining Outage probability Poisson point processes

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A Unified Framework for Wireless Connectivity Study subject to General Interference Attack

A Unified Framework for Wireless Connectivity Study subject ...

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IEEE International Conference on Communications

作者： Yang Liu Chengzhi Li Changchuan Yin Huaiyu Dai Beijing Key Laboratory of Network System Architecture Convergence Beijing University of Posts and Telecommunications Beijing China Department of Electrical and Computer Engineering North Carolina State University Raleigh NC

Connectivity is crucial to ensure information availability and survivability for wireless networks. In this paper, we propose a unified framework to study the connectivity of wireless networks under a general type of interference attack, which can address diverse applications including Cognitive Radio, Jamming attack and shadowing effect. By considering the primary users, jammers and deep fading as unified Interferers, we investigate a 3-dimensional connectivity region, defined as the set of key system parameters - the density of users, the density of Interferers and the interference range of Interferers - with which the network is connected. Further we study the impact of the Interferers' settings on node isolation probability, which is a fundamental local connectivity metric. Through percolation theory, the sufficient and necessary conditions for global connectivity are also derived. Our study is supported by simulation results.

关键词： Interference Three-dimensional displays Jamming Wireless networks Security Shadow mapping Information systems

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Distributed user association for delay-load tradeoffs in energy harvesting enabled HetNets

Distributed user association for delay-load tradeoffs in ene...

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IEEE Wireless Communications and Networking Conference Workshops (WCNCW)

作者： Hongzhang Xu Tiankui Zhang Zhimin Zeng Dantong Liu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China School of Electronic Engineering and Computer Science Queen Mary University of London London UK

ISBN: (纸本)9781479987610

Energy harvesting is an emerging technology to save on-grid power and reduce carbon emissions in wireless communications. Terminals can utilize renewable energy obtained from environment by energy harvesting facilities. This paper investigates user association problem under a flow-level traffic model in energy harvesting enabled heterogeneous networks. In this paper, all the base stations are equipped with energy harvesting facilities and assumed to be solely powered by renewable energy. The average traffic delay is denoted using queuing theory, and a fairness index is redefined to evaluate the level of load balancing. Then a convex optimization problem is formulated in order to reduce average traffic delay and improve load balancing level. To this end, an iterative algorithm completed by user and base station respectively is proposed. Simulation results show that the user association algorithm improves the load balancing level with limited sacrifice on average traffic delay compared with the existing delay-optimal algorithm, and enables a flexible tradeoff between the average traffic delay and load balancing.

关键词： Load management Delays Indexes Energy harvesting Wireless communication Load modeling Renewable energy sources

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A QoE-Driven FEC Rate Adaptation Scheme for Scalable Video Transmissions over MIMO systems

A QoE-Driven FEC Rate Adaptation Scheme for Scalable Video T...

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IEEE International Conference on Communications

作者： Xiang Chen Haiqing Du Jenq-Neng Hwang James A. Ritcey Chung-Nan Lee Department of Electrical Engineering University of Washington Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Department of Computer Science and Engineering National Sun Yat-Sen University

ISBN: (纸本)9781467364300

We propose a forward error correction (FEC) coding rate adaptation scheme which maximizes the quality of experience (QoE), for scalable video coding (SVC) based video transmissions over multi-input multi-output (MIMO) systems. The proposed scheme adaptively selects the best set of spatial channels, number of video layers and their corresponding FEC coding rate according to channel state information (CSI) from the receiver. Unlike previous work, our proposed scheme distributes the FEC encoded bit streams to multiple spatial channels so that additional diversity gains can be obtained. Due to the complexity of the optimization, we decompose the original problem into several sub-problems, which can then be solved by a heuristic algorithm. The optimal solution can be found by choosing the best among all the candidate solutions obtained from the sub-problems. The effectiveness and superb performance of our proposed scheme can be demonstrated by many simulations with different videos and channel conditions.

关键词： FEC QoE SVC MIMO Rate adaptation

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Transmission mode selection for downlink transmission in LTE-A networks

Transmission mode selection for downlink transmission in LTE...

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

作者： Jian Yu Geoffrey Ye Li Changchuan Yin Xiaolong Zhu Yusun Fu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta Georgia USA Huawei Shanghai Research Institute Shanghai China

In this paper, we investigate mode selection for coordinated multi-point (CoMP) transmission in downlink LTE-A networks, where inter-cluster interference exists. The proposed scheme selects the single-cell (SC) or coordinated beamforming (CB) transmission mode according to interference level to maximize the weighted sum rate with fairness consideration. To formulate the optimization problem, an approximated closed-form expression for the achievable rate is derived by modeling the probability distributions of signal and interference powers as Gamma distributions. Since the original optimization problem is a combinatorial and non-convex one with high complexity, a low-complexity and sub-optimal algorithm is proposed, which first performs coordinated cell selection and then transmission mode selection. Simulation results show that the closed-form approximation of the achievable rate is very tight and the proposed mode selection scheme can improve the average system throughput by 13% and the 10th percentile user throughput by 10% compared with the existing scheme.

关键词： Interference Optimization Approximation methods Closed-form solutions Downlink Signal to noise ratio Land mobile radio

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Enhanced LCCG: A novel test clock generation scheme for faster-than-at-speed delay testing

Enhanced LCCG: A novel test clock generation scheme for fast...

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Asia and South Pacific Design Automation Conference

作者： Songwei Pei Ye Geng Huawei Li Jun Liu Song Jin Beijing University of Chemical Technology Beijing 100029 China Key Laboratory of Computer System and Architecture Institute of Computing Technology Chinese Academy of Sciences Beijing CN School of Computer and Information University of Technology Hefei China School of Electrical and Electronic Engineering North China Electric Power University Baoding China

ISBN: (纸本)9781479977932

On-chip faster-than-at-speed delay testing provides a promising way for small delay defect detection. However, the frequency of on-chip generated test clock would be impacted by process variations. Hence, it requires determining the actual frequency of generated test clock to ensure the effectiveness of faster-than-at-speed delay testing. In this paper, we present a novel test clock generation scheme, namely Enhanced LCCG, for faster-than-at-speed delay testing. In the proposed scheme, faster-than-at-speed test clock is firstly generated by configuring the corresponding control information specified in the test pattern into Enhanced LCCG. Then, by constructing oscillation paths and counting the corresponding oscillation iteration numbers, the actual frequency of test clock can be measured and calculated with high resolution. Experimental results are presented to validate the proposed method.

关键词： Delays Clocks Oscillators Testing Frequency measurement Logic gates

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