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Capacity and delay in mobile cognitive networks with random way-point mobility model

AEU - International Journal of Electronics and Communications 2011年第4期65卷 288-295页

作者： Xingzhen Bai Shu Li Changjun Jiang Juan Xu Cheng Wang Lina Han The Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai 200092 China College of Information & Electrical Engineering Shandong University of Science & Technology Qingdao 266510China

We study the throughput and delay scaling laws of the mobile cognitive network. There are n primary users and m secondary users in the primary network and the secondary network, respectively. They are distributed uniformly and independently on the surface of a unit torus, moving according to the random way-point mobility model (RWMM). The primary users have priority to access the spectrum, and do not alter their protocol in the presence of the secondary network. The secondary users opportunistically use the licensed spectrum when it remains unused. Under the improved 2-hop relay policy, we derive the constant throughput of Θ ( 1 ) per primary source–destination (S–D) pair when the radius of the preservation region r p = Θ ( 1 / m ) . The expected delay scales as Θ ( n / v ( n ) ) , where v ( n ) is the average speed of the primary nodes. Moreover, if the secondary network is denser than the primary network, i.e., m = n γ with γ > 1 , the constant throughput of Θ ( 1 ) per secondary S–D pair and the expected delay of Θ ( m / v ( m ) ) can be derived surprisingly when the radius of the avoidance region r s = Θ ( 1 / n ) and r p = Θ ( 1 / m ) , where v ( m ) is the average speed of the secondary nodes.

关键词： Throughput Delay Scaling law Cognitive networks Mobility

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A novel discrete particle swarm optimization algorithm for meta-task assignment in heterogeneous computing systems

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Microprocessors and Microsystems 2011年第1期35卷 10-17页

作者： Qinma Kang Hong He The Key Laboratory of “Embedded System and Service Computing” Ministry of Education Tongji University Shanghai 201804 PR China School of Information Engineering Shandong University at Weihai Weihai 264209 PR China

Optimal assignment of a meta-task in heterogeneous computing systems is NP-complete in the general case. Therefore, heuristic approaches must be employed to find good solutions within a reasonable time. We propose a novel discrete particle swarm optimization (DPSO) algorithm for this problem. Firstly, to make particle swarm optimization algorithm more suitable for solving task assignment problems, particles are represented as integer vectors and a new position update method is developed based on discrete domain. Secondly, an effective variable neighborhood descent algorithm is applied to emphasize exploitation. In addition, migration mechanism is introduced with the hope to escape from possible local optimum and to balance the exploration and exploitation. Computational simulations and comparisons based on a set of benchmark instances indicate that the proposed DPSO algorithm is a viable approach for the task assignment problem.

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Study on the effect of hydraulic immersion on the strength and deformation characteristics of sandstone

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1st International Conference on Civil engineering, Architecture and Building Materials, CEABM 2011

作者： Wang, Ruihong Jiang, Yuzhou Guo, Jing Zhou, Jifang Key Laboratory of Geological Hazards on Three Gorges Reservoir Area China Three Gorges University Ministry of Education No8 Daxue Road Xilin District Yichang 443002 China Key Laboratory of Geotechnical Mechanics and Engineering Yangtze River Scientific Research Institute Ministry of Water Resources No.23 Huangpu Big Road Wuhan 430010 China Er'tan Hydropower Development Company Ltd. No.98 Shuanglin Road Chengdu 610021 China

ISBN: (纸本)9783037851258

During the hydraulic structure design, the stability of abutment slope is critical to the normal operation of hydraulic structure. Through the tests, the effects of different hydraulic pressure on the strength and deformation characteristics of sandstone were studied, and the variation characteristics of rock masses with joints under secondary loading after excavation damage were analyzed as well. Test results show that: 1. When the samples without immersion secondly load until complete failure, ultimate strain increases slightly than the first loading, of which the increasing value is 7.5%;elastic modulus has a relatively large reduction than the first, which reduces 22.8%;deformation modulus has a less reduction, which is about 3.3%;2. When considering the softening action of different hydraulic pressure on samples, ultimate strain increases by about 23% than that without consideration of immersion effect;elastic modulus reduces about 53%;deformation modulus reduces about 39%;3. With the increment of immersion pressure, sample strength decreases greater, so does the softening effect of water on rock samples. With the increment of pressure, the strength of rock with joints has a relatively large reduction, which is from 27% to 41%, and the increasing value of intact rock mass isn't great, which is only from 25% to 27%. Jointed rock masses are more sensitive to the softening effect of water, and mechanical properties weaken obviously after long-term immersion with unstable problem. © (2011) Trans Tech Publications.

关键词： Sandstone

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RESTful web service composition: Extracting a process model from Linear Logic theorem proving

RESTful web service composition: Extracting a process model ...

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2011 7th International Conference on Next Generation Web Services Practices, NWeSP 2011

作者： Zhao, Xia Liu, Enjie Clapworthy, Gordon J. Ye, Na Lu, Yueming Department of Computer Science and Technology University of Bedfordshire Luton United Kingdom School of Information and Control Engineering Xi'An University of Architecture and Technology Xi'an China School of Electronic and Information Engineering Xi'An Jiao Tong University Xi'an China Key Laboratory of Trustworthy Distributed Computing and Service Beijing University of Posts and Telecommunications Ministry of Education Beijing China

ISBN: (纸本)9781457711268

This paper introduces a two-stage Linear Logic based program synthesis approach to automatic RESTful web service composition. The Linear Logic theorem proof is applied at both resource and service invocation method levels, which greatly improves the searching efficiency and guarantees the correctness and completeness of the service composition. Furthermore, the process calculus is used as formalism for the composition process, which enables the approach to be executable at the business management level. The process calculus is attached to the Linear Logic inference rules in the style of type theory, so the process model is extracted directly from the complete proof. An example is given to show the extraction of a process model from a Linear Logic proof search. © 2011 IEEE.

关键词： Computer circuits

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Upper bounds on lifetime of ordinary clustering ultra wide band sensor networks

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Ruan Jian Xue Bao/Journal of Software 2011年第2期22卷 313-322页

作者： Xu, Juan Hong, Yong-Fa Wang, Cheng Bai, Xing-Zhen College of Electronics and Information Engineering Tongji University Shanghai 200092 China Key Laboratory of Embedded System and Service Computing of the Ministry of Education Tongji University Shanghai 200092 China College of Information Science and Engineering Shandong University of Science and Technology Qingdao 266510 China

This paper considers the time hopping impulse radio ultra wide band (TH-IR UWB) sensor networks, with n sensor nodes uniformly and independently located on a square and a Sink. The upper bounds on the lifetime of ordinary clustering dense and extended TH-IR UWB sensor networks are derived respectively. For ordinary clustering networks, the cluster head aggregates data from the nodes within its own cluster, and relays data to other cluster heads. The results indicate that the upper bounds on the lifetime of ordinary clustering dense TH-IR UWB are in proportion with the node density (or the number of nodes), while the upper bounds on the lifetime of extended networks are inversely proportional to the size of the deployment area (or the number of nodes). The results also reveal that the upper bound on the lifetime of dense network in the ideal case are longer than those of the static network by a factor of (n/log n)1/2, and the upper bound on the lifetime of extended network in the ideal case are longer than those of the static network by a factor of (λn/log(λn))1/2. Therefore, sensor nodes, or the Sink moving randomly in the square, can improve the lifetime of ordinary clustering TH-IR UWB sensor network. © 2011 ISCAS.

关键词： Energy dissipation

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Parameter selection in public key cryptosystem based on Chebyshev Polynomials over finite field

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Journal of Communications 2011年第5期6卷 400-408页

作者： Li, Zhihui Cui, Yidong Jin, Yuehui Xu, Huimin Key Laboratory of Trustworthy Distributed Computing and Service Ministry of Education Beijing University of Posts and Telecommunications Beijing China School of Information and communication Engineering Beijing University of Posts and Telecommunications Beijing China

A recently proposed public key cryptosystem based on Chebyshev polynomials suggests a new approach to data encryption. But the security of the cryptosystem has not been investigated in depth, for lack of an appropriate analysis method. In this paper, a new representation of Chebyshev polynomial is introduced to study security issues of the cryptosystem. The properties of Chebyshev polynomial sequence are presented, and their impact on the cryptosystem are discussed. Finally some principles for parameter selection for the cryptosystem are proposed. The methodology used in this paper is supposed to offer a useful means for future researches on this topic. © 2011 ACADEMY PUBLISHER.

关键词： Chebyshev polynomials

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Through-wall synthetic aperture radar based on finite beamwidth processing

Through-wall synthetic aperture radar based on finite beamwi...

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Microwaves, Radar and Remote Sensing Symposium, MRRS

作者： Jiabing Zhu Yi Hong Liang Tao East China Research Institute of Electronic Engineering Hefei Anhui China Education Ministry Key Laboratory of Intelligent Computing and Signal Processing Anhui University China

Standard backprojection technique is used in typical through-wall synthetic aperture radar (TWSAR) image, it implicitly assumes infinite beamwidth, whereby the entire target area is illuminated and returns are collected from all points in the imaging grid, and this decreases the efficiency of the algorithm by summing over unnecessary grid points. In order to eliminate the disadvantage, the time-domain backprojection method based on finite beamwidth processing is proposed in the paper. The processing method is designed to be more physically realistic by accounting for the actual antenna pattern. Simulation results show that depending on the width of the effective beam, the number of processing loops can be reduced by up to 50%, while still maintaining good image quality in terms of the reconstructed target response.

关键词： Radar imaging Apertures Imaging Finite element methods Signal processing algorithms

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Fast adaptive interpolation filter algorithm for bi-predicted frame in video coding

Fast adaptive interpolation filter algorithm for bi-predicte...

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International Conference on Multimedia Technology

作者： Huichao Gao Feng Cen Weisheng Xu Key Laboratory of Embedded System and Service Computing Ministry of Education University of Tongji Shanghai China College of Electronics and Information Engineering University of Tongji Shanghai China

ISBN: (纸本)9781612847719

This paper proposes a novel adaptive interpolation filter (AIF) to reduce computational complexity and bit-rate of video coding. In the proposed AIF, the filter coefficients of B frames, which are predicted from those of adjacent P frames with a novel parabolic model, are unnecessary to transmit. Experimental results show that the coding complexity is reduced by 40.22% with no penalty on coding efficiency and 1.59% bit rate reduction is achieved at low bit-rate against conventional AIF.

关键词： Interpolation Wiener filter Adaptive filters Encoding Information filters Complexity theory

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A Rigid Structure Matching-Based Noise Data Processing Approach for Human Motion Capture

A Rigid Structure Matching-Based Noise Data Processing Appro...

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Workshop on Digital Media and Digital Content Management (DMDCM)

作者： Xiaopeng Wei Boxiang Xiao Qiang Zhang Rui Liu Key Laboratory of Advanced Design and Intelligent Computing Ministry of Education Dalian University Dalian China School of Mechanical Engineering Dalian University of Technology Dalian China

A noise data processing algorithm based on rigid structure matching for human motion capture (MoCap) is presented in this paper. The noise model is related to parts of human body, but not to trajectories of markers as most used in traditional approaches. Three issues are addressed in this method: rigid structure matching, semantic restriction and noise reduction, and they are three steps of data processing. First, human body is divided into seven main parts: head, chest, waist, hands and legs, and all parts' candidate parts are generated by algorithm of rigid structure matching from motion data. Missing markers can be automatically reconstructed by existing markers on a same rigid structure. Subsequently, one group of parts with most possibility is determined as initial processed data by semantic restriction. Finally, an impulse noise model is found based on the analysis of data, and the noise has been filtered. At the end, the main conclusions of this research are drawn, and the advantages and limitations of this approach are discussed respectively. The algorithm presented can be easily implemented and performed, and the processed motion data can be expediently used in human body animation. The efficiency of the method is illustrated by the experiments.

关键词： Joints Semantics Noise Data processing Data models Noise reduction Humans

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Variation of Received Signal Strength in Wireless Sensor Network

Variation of Received Signal Strength in Wireless Sensor Net...

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International Conference on Advanced Computer Control, ICACC

作者： Lisheng Xu Feifei Yang Yuqi Jiang Lei Zhang Cong Feng Nan Bao Key Laboratory of Medical Image Computing Ministry of Education Northeastern University Shenyang China Sino-Dutch School of Biomedical and Information Engineering Northeastern University Shenyang China

ISBN: (纸本)9781424488094

Semiconductor manufacturers provide low-cost, low-power and short-range solutions for the application of Wireless Sensor Network (WSN), such as ZigBee, Bluetooth, Wi-Fi etc. The quality of radio frequency signal, which carries information in wireless communication channel, is the key to WSN. But it is easily influenced by the external environment. Received Signal Strength Indicator (RSSI) is a measurement for the quality of radio frequency signal which is often used in field of space localization. This paper comprehensively analyses the characteristics of RSSI possibly influenced by the factors such as temperature, the height of sensor node's position, the type of antenna and the electromagnetic interference of human body. We found that the attenuation of Received Signal Strength (RSS) varies about 5.0 dBm with the change of temperature in every 10 centigrade. The ground can reduce the radiation area of wireless signal, so that RSS is dramatically influenced by the height of its position. Patch antenna causes the attenuation of RSS about 11.2 dBm larger than helix antenna in the distance of 25 m. If the sensor node is wore in human body, the posterior position leads to the attenuation of RSS about 13.0~16.2 dBm larger than anterior position in a specified distance range due to the electromagnetic interference of human body. Finally, some improvement devices were raised here for the WSN in the application of home healthcare according to the qualified effects of various environmental factors.

关键词： Antenna measurements Monitoring Receiving antennas Biomedical monitoring Wireless sensor networks

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