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Metamaterial absorbers realized in an X-band rectangular waveguide

Chinese Physics B 2012年第11期21卷 474-478页

作者：黄勇军文光俊李建钟靖平王平孙元华 O.Gordon 朱卫仁 Key Laboratory of Broadband Optical Fiber Transmission&Communication Networks School of Communication and Information EngineeringUniversity of Electronic Science and Technology of China Advanced Computing and Simulation Laboratory(AχL) Department of Electrical and Computer Systems EngineeringMonash University

In this paper, we demonstrate six types of metamaterial absorbers （MMAs） by measuring their absorptivities in an X-band （8 12 GHz） rectangular waveguide. Some of the MMAs have been demonstrated previously by using the free space measurement method, and the others are proposed firstly in this paper. The measured results show that all of the six MMAs exhibit high absorptivities above 98%, which have similar absorbing characteristics to those measured in the free space. The numerically obtained surface current densities for each MMA show that the absorbing mechanism is the same as that under the free space conditions. Such a demonstration method is superior to the conventional free space measurement method due to the small-scale test samples required, the simple measure device, and its low cost. Most importantly, the proposed method opens a way to enable MMAs to be used in microwave applications such as matched terminations.

关键词： metamaterial absorber electric resonator rectangular waveguide

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Inertial estimator learning automata

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IEICE Transactions on Fundamentals of Electronics, Communications and computer sciences 2012年第6期E95-A卷 1041-1048页

作者： Zhang, Junqi Ni, Lina Xie, Chen Gao, Shangce Tang, Zheng Department of Computer Science and Technology Key Laboratory of Embedded System and Service Computing Tongji University Shanghai 200092 China College of Information Science and Engineering Shandong University of Science and Technology Qingdao China Department of Intellectual Information Systems Engineering University of Toyama Toyama-shi 930-8555 Japan

This paper presents an inertial estimator learning automata scheme by which both the short-term and long-term perspectives of the environment can be incorporated in the stochastic estimator-the long term information crystallized in terms of the running reward-probability estimates, and the short term information used by considering whether the most recent response was a reward or a penalty. Thus, when the shortterm perspective is considered, the stochastic estimator becomes pertinent in the context of the estimator algorithms. The proposed automata employ an inertial weight estimator as the short-term perspective to achieve a rapid and accurate convergence when operating in stationary random environments. According to the proposed inertial estimator scheme, the estimates of the reward probabilities of actions are affected by the last response from environment. In this way, actions that have gotten the positive response from environment in the short time, have the opportunity to be estimated as "optimal", to increase their choice probability and consequently, to be selected. The estimates become more reliable and consequently, the automaton rapidly and accurately converges to the optimal action. The asymptotic behavior of the proposed scheme is analyzed and it is proved to be Ε-optimal in every stationary random environment. Extensive simulation results indicate that the proposed algorithm converges faster than the traditional stochastic-estimator-based SERI scheme, and the deterministicestimator- based DGPA and DPRI schemes when operating in stationary random environments. Copyright © 2012 The Institute of Electronics, information and Communication Engineers.

关键词： Probability

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Reconstructing 3D human poses from uncalibrated monocular images with strong perspective effects

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Journal of Computational information Systems 2012年第15期8卷 6437-6445页

作者： Chen, Shu Peng, Xiaoning School of Information Engineering Xiangtan Universtiy Xiangtan 411105 China Key Laboratory of Intelligent Computing and Information Processing Ministry of Education Xiangtan 411105 China School of Information Science and Engineering Central South University Changsha 410083 China Department of Computer Science and Technology Huaihua College Huaihua 418008 China

This paper present a geometric method to reconstruct human motion pose from 2D point correspondences obtained from uncalibrated monocular images. The proposed algorithm can handle images with very strong perspective effects, which is guaranteed by the fact that only one scale factor corresponding to the root joint in the skeleton model is required estimating. To take fully advantage of this fact, a system of two nonlinear equations with two variables to estimate the scale factor of the root joint is established, and the scale factor of the root joint is optimized by the Gauss-Newton iterative scheme. At last, a framework to reconstruct human motion pose is presented. Quantitive analysis of the experiment results based on several real monocular video sequences shows the accuracy of the scale factor as well as the accuracy of the pose reconstruction. © 2012 Binary information Press.

关键词： Nonlinear equations

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A Personalized Sleep Quality Assessment Mechanism Based on Sleep Pattern Analysis

A Personalized Sleep Quality Assessment Mechanism Based on S...

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International Conference on Innovations in Bio-inspired computing and Applications (IBICA)

作者： Shiao-Ping Cheng Hsing Mei Web Computing Laboratory Department of Computer Science and Information Engineering Fu Jen Catholic University Taipei Taiwan

Most sleep management systems lack reliable assessment of sleep quality and receive single information source only. In this paper, we proposed a sleep quality assessment mechanism based on the physiological sleep pattern with scenarios of multiple data sources. This mechanism provides an intuitive personalized sleep quotient which encourages users to have long-term usage of sleep management service. It further helps users to understand their sleep patterns and adjust sleep habits. In addition, sleep medical professionals can strengthen the diagnostic judgment with this assessment mechanism.

关键词： Sleep Switching circuits Biomedical monitoring Quality assessment Medical diagnostic imaging Physiology Sun

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Integrating nature-inspired optimization algorithms to K-means clustering

Integrating nature-inspired optimization algorithms to K-mea...

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7th International Conference on Digital information Management, ICDIM 2012

作者： Tang, Rui Fong, Simon Yang, Xin-She Deb, Suash Department of Computer and Information Science University of Macau Taipa China Mathematics and Scientific Computing National Physical Laboratory Teddington United Kingdom Department of Computer Science and Engineering C. V. Raman College of Engineering Bidyanagar India

ISBN: (纸本)9781467324281

Although K-means clustering algorithm is simple and popular, it has a fundamental drawback of falling into local optima that depend on the randomly generated initial centroid values. Optimization algorithms are well known for their ability to guide iterative computation in searching for global optima. They also speed up the clustering process by achieving early convergence. Contemporary optimization algorithms inspired by biology, including the Wolf, Firefly, Cuckoo, Bat and Ant algorithms, simulate swarm behavior in which peers are attracted while steering towards a global objective. It is found that these bio-inspired algorithms have their own virtues and could be logically integrated into K-means clustering to avoid local optima during iteration to convergence. In this paper, the constructs of the integration of bio-inspired optimization methods into K-means clustering are presented. The extended versions of clustering algorithms integrated with bio-inspired optimization methods produce improved results. Experiments are conducted to validate the benefits of the proposed approach. © 2012 IEEE.

关键词： Ant colony optimization

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Wolf search algorithm with ephemeral memory

Wolf search algorithm with ephemeral memory

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7th International Conference on Digital information Management, ICDIM 2012

ISBN: (纸本)9781467324281

In computer science, a computational challenge exists in finding a globally optimized solution from a tremendously large search space. Heuristic optimization methods have therefore been created that can search the very large spaces of candidate solutions. These methods have been extensively studied in the past, and progressively extended in order to suit a wide range of optimization problems. Researchers recently have invented a collection of heuristic optimization methods inspired by the movements of animals and insects (e.g., Firefly, Cuckoos, Bats and Accelerated PSO) with the advantages of efficient computation and easy implementation. This paper proposes a new bio-inspired heuristic optimization algorithm called the Wolf Search Algorithm (WSA) that imitates the way wolves search for food and survive by avoiding their enemies. The contribution of the paper is twofold: 1. for verifying the efficacy of the WSA the algorithm is tested quantitatively and compared to other heuristic algorithms under a range of popular non-convex functions used as performance test problems for optimization algorithms;2. The WSA is investigated with respective to its memory requirement. Superior results are observed in most tests. © 2012 IEEE.

关键词： Heuristic algorithms

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Propagation-based social-aware replication for social video contents

Propagation-based social-aware replication for social video ...

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20th ACM International Conference on Multimedia, MM 2012

作者： Wang, Zhi Sun, Lifeng Chen, Xiangwen Zhu, Wenwu Liu, Jiangchuan Chen, Minghua Yang, Shiqiang Tsinghua National Laboratory for Information Science and Technology Department of Computer Science and Technology Tsinghua University Beijing China Department of Information Engineering Chinese University of Hong Kong Hong Kong School of Computing Science Simon Fraser University Vancouver BC Canada

ISBN: (纸本)9781450310895

Online social network has reshaped the way how video contents are generated, distributed and consumed on today's Internet. Given the massive number of videos generated and shared in online social networks, it has been popular for users to directly access video contents in their preferred social network services. It is intriguing to study the service provision of social video contents for global users with satisfactory quality-of-experience. In this paper, we conduct large-scale measurement of a real-world online social network system to study the propagation of the social video contents. We have summarized important characteristics from the video propagation patterns, including social locality, geographical locality and temporal locality. Motivated by the measurement insights, we propose a propagation-based social-aware replication framework using a hybrid edge-cloud and peer-assisted architecture, namely PSAR, to serve the social video contents. Our replication strategies in PSAR are based on the design of three propagation-based replication indices, including a geographic influence index and a content propagation index to guide how the edge-cloud servers backup the videos, and a social influence index to guide how peers cache the videos for their friends. By incorporating these replication indices into our system design, PSAR has significantly improved the replication performance and the video service quality. Our trace-driven experiments further demonstrate the effectiveness and superiority of PSAR, which improves the local download ratio in the edge-cloud replication by 30%, and the local cache hit ratio in the peer-assisted replication by 40%, against traditional approaches. © 2012 ACM.

关键词： Social networking (online)

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Efficient approximation of the maximal preference scores by lightweight cubic views

Efficient approximation of the maximal preference scores by ...

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15th International Conference on Extending Database Technology, EDBT 2012

作者： Chen, Yueguo Cui, Bin Du, Xiaoyong Tung, Anthony K. H. Key Laboratory of Data Engineering and Knowledge Engineering Renmin University of China MOE China Department of Computer Science Peking University Beijing China School of Information Renmin University of China Beijing China School of Computing National University of Singapore Singapore Singapore

ISBN: (纸本)9781450307901

Given a multi-features data set, a best preference query (BPQ) computes the maximal preference score (MPS) that the tuples in the data set can achieve with respect to a preference function. BPQs are very useful in applications where users want to efficiently check whether many individual data sets contain tuples that are of interest to them. Although a BPQ can be naïvely answered by issuing a top-1 query and computing the score from the returned tuple, doing so might require to load a larger number of tuples externally. In this paper, we address the problem of efficient processing BPQs by using lightweight cubic (3-dimensional) views. With these in-memory views, the MPSs of BPQs can be efficiently estimated with an error bound guaranteed, by paying only a small number of I/Os. Extensive experimental results over real-life data sets show that our approximate solution can achieve the efficiency of up to three orders of magnitude compared to exact solutions, with certain accuracy guaranteed. © 2012 ACM.

关键词： best preference score materialized views preference query top-k query

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Providing fairness on shared-memory multiprocessors via process scheduling 12

Providing fairness on shared-memory multiprocessors via proc...

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12th Joint International Conference on Measurement and Modeling of computer Systems, ACM SIGMETRICS/Performance 2012

作者： Xu, Di Wu, Chenggang Yew, Pen-Chung Li, Jianjun Wang, Zhenjiang State Key Laboratory of Computer Architecture Institute of Computing Technology Chinese Academy of Sciences Beijing China Graduate University Chinese Academy of Sciences Beijing China Department of Computer Science and Engineering University of Minnesota at Twin-Cities MN United States Institute of Information Science Academia Sinica Taiwan

ISBN: (纸本)9781450310970

Competition for shared memory resources on multiprocessors is the most dominant cause for slowing down applications and makes their performance varies unpredictably. It exacerbates the need for Quality of Service (QoS) on such systems. In this paper, we propose a fair-progress process scheduling (FPS) policy to improve system fairness. Its strategy is to force the equally-weighted applications to have the same amount of slowdown when they run concurrently. The basic approach is to monitor the progress of all applications at runtime. When we find an application suffered more slowdown and accumulated less effective work than others, we allocate more CPU time to give it a better parity. Our policy also allows different weights to different threads, and provides an effective and robust tuner that allows the OS to freely make tradeoffs between system fairness and higher throughput. Evaluation results show that FPS can significantly improve system fairness by an average of 53.5% and 65.0% on a 4-core processor with a private cache and a 4-core processor with a shared cache, respectively. The penalty is about 1.1% and 1.6% of the system throughput. For memory-intensive workloads, FPS also improves system fairness by an average of 45.2% and 21.1% on 4-core and 8-core system respectively at the expense of a throughput loss of about 2%. © 2012 ACM.

关键词： Throughput

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Accountable authority key policy attribute-based encryption

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science China(information sciences) 2012年第7期55卷 1631-1638页

作者： WANG YongTao 1,2 ,CHEN KeFei 1,3 ,LONG Yu 1,4 & LIU ZhaoHui 2 1 department of computer science and engineering,Shanghai Jiao Tong University,Shanghai 200240,China 2 China information Technology Security Evaluation Center,Beijing 100085,China 3 Shanghai Key laboratory of Scalable computing and Systems,Shanghai Jiao Tong University,Shanghai,200240,China 4 State Key laboratory of information Security,Graduate School of Chinese Academy of sciences,100039,China 1. Department of Computer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China2. China Information Technology Security Evaluation Center Beijing 100085 China3. Shanghai Key Laboratory of Scalable Computing and Systems Shanghai Jiao Tong University Shanghai 200240 China4. State Key Laboratory of Information Security Graduate School of Chinese Academy of Sciences Beijing 100039 China

We present an accountable authority key policy attribute-based encryption (A-KPABE) *** this paper,we extend Goyal's work to key policy attribute-based encryption *** first generalize the notion of accountable authority in key policy attribute-based encryption scenario,and then give a *** addition,our scheme is shown to be secure in the standard model under the modified Bilinear Decisional Diffie-Hellman (mBDDH) assumption.

关键词： accountable authority key policy attribute-based encryption standard model access structure

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