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On multicast throughput scaling of hybrid wireless networks with general node density

Computer Networks 2011年第15期55卷 3548-3561页

作者： Cheng Wang Changjun Jiang Xiang-Yang Li Yunhao Liu Department of Computer Science and Technology Tongji University Shanghai China Key Laboratory of Embedded System and Service Computing Ministry of Education China Department of Computer Science Illinois Institute of Technology Chicago IL 60616 United States TNLIST School of Software Tsinghua University China

In this paper, we consider hybrid wireless networks with a general node density λ ∈ [1, n ], where n ad hoc nodes are uniformly distributed and m base stations (BSs) are regularly placed in a square region A ( n , A ) = 1 , A × 1 , A with A ∈ [1, n ]. We focus on multicast sessions in which each ad hoc node as a user chooses randomly d ad hoc nodes as its destinations. Specifically, when d = 1 (or d = n − 1), a multicast session is essentially a unicast (or broadcast) session. We study the asymptotic multicast throughput for such a hybrid wireless network according to different cases in terms of m ∈ [1, n ] and d ∈ [1, n ], as n → ∞. To be specific, we design two types of multicast schemes, called hybrid scheme and BS - based scheme , respectively. For the hybrid scheme, there are two alternative routing backbones : sparse backbones and dense backbones . Particularly, according to different regimes of the node density λ = n A , we derive the thresholds in terms of m and d . Depending on these thresholds, we determine which scheme is preferred for the better performance of network throughput.

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Task assignment in heterogeneous computing systems using an effective iterated greedy algorithm

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Journal of systems and Software 2011年第6期84卷 985-992页

作者： Qinma Kang Hong He Huimin Song Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai 201804 China School of Information Engineering Shandong University at Weihai 180 Wenhua Xilu Weihai 264209 China School of Mathematics and Statistics Shandong University at Weihai Weihai 264209 China

A fundamental issue affecting the performance of a parallel application running on a heterogeneous computing system is the assignment of tasks to the processors in the system. The task assignment problem for more than three processors is known to be NP-hard, and therefore satisfactory suboptimal solutions obtainable in an acceptable amount of time are generally sought. This paper proposes a simple and effective iterative greedy algorithm to deal with the problem with goal of minimizing the total sum of execution and communication costs. The main idea in this algorithm is to improve the quality of the assignment in an iterative manner using results from previous iterations. The algorithm first uses a constructive heuristic to find an initial assignment and iteratively improves it in a greedy way. Through simulations over a wide range of parameters, we have demonstrated the effectiveness of our algorithm by comparing it with recent competing task assignment algorithms in the literature.

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Trust reasoning and optimization based on associate petri net

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ICIC Express Letters 2011年第3期5卷 791-796页

作者： Fang, Xianwen Yan, Chungang Fan, Xiaoqin Yin, Zhixiang Department of Information and Computing Science Anhui University of Science and Technology No. 168 Shungengzhong Road Huainan 232001 China Key Lab of Embedded System and Service Computing Ministry of Education Tongji University No. 1239 Siping Road Shanghai 201804 China

Trust issue is an important problem both in social field and information field. At present, there are few methods considering the interaction behavior relativity between models which can judge the interaction influence, so the obtained trust value is imprecise and unreliable. In the paper, behavior-aware trust computation and reasoning methods based on Associate Petri net (APN) are presented, which use the APN reasoning and take the interaction relativity into account. Using Genetic Algorithm (GA) combined with the properties of APN, a trust optimization method is obtained. Theoretical analysis and experimental results indicate that the method owns both lower computation cost and lower error rate. © 2011 ISSN 1881-803X.

关键词： Genetic algorithms

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Knowledge Granulation in Interval-Valued Information systems

Knowledge Granulation in Interval-Valued Information Systems

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International Workshop on Intelligent systems and Applications, ISA

作者： Nan Zhang Duoqian Miao Can Gao Department of Computer Science and Technology University of Tongji Shanghai China Department of Electrical and Computer Engineering University of Alberta Edmonton AB Canada Key Laboratory of Embedded System and Service Computing of Ministry of Education University of Tongji Shanghai China

Rough set theory, proposed by Pawlak, has been proved to be a mathematical tool to deal with vagueness and uncertainty in intelligent information processing. In this paper, we propose the concept of knowledge granulation in interval-valued information systems, and discuss some important properties. From these properties, it can be shown that the proposed knowledge granulation provides important approaches to measuring the discernibility of different knowledge. It may be helpful for rule evaluation and knowledge discovery in interval-valued information systems.

关键词： Information systems Approximation methods Uncertainty Rough sets Computers Entropy

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Polynomial-time hierarchy of computable reals

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Journal of Computational Information systems 2011年第4期7卷 1108-1115页

作者： Chen, Qingliang Su, Kaile Wu, Lijun Department of Computer Science Jinan University Guangzhou 510632 China Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai China Key Laboratory of High Confidence Software Technologies Ministry of Education Peking University Beijing China Institute for Integrated and Intelligent Systems Griffith University Brisbane Australia School of Computer Science and Engineering University of Electronic Science and Technology Chengdu 610054 China

In mathematics, various representations of real numbers have been investigated and all these representations are proved to be mathematically equivalent. Furthermore, it is known that all effective versions of these representations lead to the same class of "computable real numbers". However, when subrecursive (such as primitive recursive) is taken into account, these representations can lead to different notions of "computable real numbers". This paper will look into the polynomial-time version of the problem for computable real numbers under different representations. We will summarize the known results to exhibit the comprehensive hierarchy they form. Our goal is to clarify systematically how the polynomial-time computability depends on the representations of the real numbers. Copyright © 2011 Binary Information Press.

关键词： Polynomial approximation

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Adaptive output feedback control for uncertain nonholonomic chained systems

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Journal of Central South University 2010年第3期17卷 572-579页

作者：袁占平王祝萍陈启军 Department of Electronics and Information Engineering Tongji University Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University

An adaptive output feedback control was proposed to deal with a class of nonholonomic systems in chained form with strong nonlinear disturbances and drift terms. The objective was to design adaptive nonlinear output feedback laws such that the closed-loop systems were globally asymptotically stable, while the estimated parameters remained bounded. The proposed systematic strategy combined input-state-scaling with backstepping technique. The adaptive output feedback controller was designed for a general case of uncertain chained system. Furthermore, one special case was considered. Simulation results demonstrate the effectiveness of the proposed controllers.

关键词： adaptive output feedback input-state scaling backstepping nonholonomic system

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SelectCast: Scalable data aggregation scheme in wireless sensor networks

SelectCast: Scalable data aggregation scheme in wireless sen...

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IEEE Annual Joint Conference: INFOCOM, IEEE Computer and Communications Societies

作者： Cheng Wang Shaojie Tang Xiang-Yang Li Changjun Jiang Key Laboratory of Embedded System and Service Computing Ministry of Education Shanghai China Department of Computer Science University of Tongji Shanghai China Department of Computer Science Illinois Institute of Technology Chicago IL USA TNLIST School of Software Tsinghua University China

In this work, for a wireless sensor network (WSN) of n randomly placed sensors with node density λ ∈ [1, n], we study the tradeoffs between the aggregation throughput and gathering efficiency. The gathering efficiency refers to the ratio of the number of the sensors whose data have been gathered to the total number of sensors. Specifically, we design two efficient aggregation schemes, called single-hop-length (SLH) scheme and multiple-hop-length (MLH) scheme. By novelly integrating these two schemes, we theoretically prove that our protocol achieves the optimal tradeoffs, and derive the optimal aggregation throughput depending on a given threshold value (lower bound) on gathering efficiency. Particularly, we show that under the MLH scheme, for a practically important set of symmetric functions called perfectly compressible functions, including the mean, max, or various kinds of indicator functions, etc., the data from Θ(n) sensors can be aggregated to the sink at the throughput of a constant order Θ(1), implying that our MLH scheme is indeed scalable.

关键词： TV Wireless sensor networks Power capacitors Blogs Lattices

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Neurological rehabilitation of stroke patients via motor imaginary-based brain-computer interface technology

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Neural Regeneration Research 2011年第28期6卷 2198-2202页

作者： Hongyu Sun Yang Xiang Mingdao Yang Department of Computer Science and Technology Tongji University Shanghai 201804 China College of Information and Electrical Engineering Shandong University of Science and Technology China Key Laboratory of Embedded System and Service Computing Ministry of Education of the People＇s Republic of China Tongji University Shanghai 201804 China Qingdao Economic ＆ Technical Development Area First People＇s Hospital Qingdao 266555 Shangdong Province China

The present study utilized motor imaginary-based brain-computer interface technology combined with rehabilitation training in 20 stroke patients. Results from the Berg Balance Scale and the Holden Walking Classification were significantly greater at 4 weeks after treatment （P 〈 0.01）, which suggested that motor imaginary-based brain-computer interface technology improved balance and walking in stroke patients.

关键词： brain-computer interface motor cortex neuronal plasticity rehabilitation stroke neural regeneration

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Verification of web service protocols by logic of knowledge

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Journal of Information and Computational Science 2011年第6期8卷 921-932页

作者： Chen, Qingliang Su, Kaile Cao, Ying Liu, Chanjuan School of Electronics Engineering and Computer Science Peking University Beijing 100871 China Department of Computer Science Jinan University Guangzhou 510632 China Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai 200000 China Institute for Integrated and Intelligent Systems Griffith University Brisbane Australia

Web services is a popular distributed systems technology and its effectiveness and efficiency rely badly on the underlying protocols. And web service protocols are designed in XML formats so the message structures within are quite different from the conventional ones. Therefore, the well-established formal verification techniques for conventional protocols, which have gained substantial achievements in practice, cannot be applied directly to them because of the inherently different syntax. In this paper, we propose a justification-oriented and automatic formal approach to verify, in the standard Dolev-Yao model, concerned security properties expressed as epistemic notions, i. e., logic of knowledge, for web service protocols, based on a fault-preserving mapping tool called SuD (SOAP under Dolev-Yao). Our approach is significant because, instead of finding flaws in finite number of protocol sessions, the specifications we are to verify can hold in arbitrary number of sessions. © 2011 Binary Information Press.

关键词： Web services

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Modeling and analysis of dual-arm cluster tools for wafer fabrication with revisiting

Modeling and analysis of dual-arm cluster tools for wafer fa...

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IEEE International Conference on Automation Science and Engineering (CASE)

作者： Yan Qiao NaiQi Wu MengChu Zhou Department of Industrial Engineering School of Mechatronics Engineering Guangdong University of Technology Guangzhou China Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai China Department of Electrical and Computer Engineering New Jersey Institute of Technology Newark NJ USA

Some wafer fabrication processes are repeated processes, e.g. atomic layer deposition (ALD) process. For such processes, the wafers need to visit some processing modules for a number of times, which complicates the cycle time analysis. This paper studies the cycle time analysis problem for such processes. With a Petri net model, it is found that such processes contain local cycles involving only the revisiting PMs and global cycles involving both revisiting and non-revisiting PMs. The process switches between these two types of cycles such that the process never reaches a steady state. Based on this finding, the mechanism underlying such processes is revealed and analytical expressions are given for the calculation of their cycle time. Illustrative examples are presented to show the application of the proposed approach.

关键词： Robots Semiconductor device modeling Fabrication Schedules Analytical models system recovery Load modeling

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