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Optimal power allocation for cognitive relay networks: amplify-and-forward versus selection relay

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science china(Information sciences) 2011年第4期54卷 861-872页

作者： YUE WenJing 1,2.ZHENG BaoYu 1,2.MENG QingMin 1,YUE WenJie 3 & CUI JingWu 1 1 Institute of Signal Processing and Transmission,Nanjing University of Posts and Telecommunications,Nanjing 2.0003,china 2.department of Electronic {2.,shanghai Jiaotong University,shanghai 2.02.0,china 3 Shanxi Institute of Educational science,Taiyuan 030009,china 1. Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China2. Department of Electronic Engineering Shanghai Jiaotong University Shanghai 200240 China3. Shanxi Institute of Educational Science Taiyuan 030009 China

We consider a cognitive relay network which is defined by a source,a destination,and cognitive relay nodes and primary user *** this network,a source is assisted by cognitive relay nodes which allow coexisting with primary user nodes by imposing severe constraints on the transmission power so that they operate below the noise floor of primary user *** this paper,we mainly study the power allocation strategies of this system to minimize the outage probability subject to total and individual power constraints for cognitive relay nodes and subject to interference constraints for primary user nodes.A relay transmission scheme,namely amplify-and-forward (AF),is *** first present an optimal power allocation (OPA) scheme to minimize the system outage probability,based on instantaneous channel state information among the source,destination and relay nodes and mean channel gains between primary user nodes and cognitive ***,we propose a selection AF scheme (S-AF) where the single best relay is chosen to assist in the transmission and study power allocation strategy for S-AF to minimize outage *** analytical power allocation strategies have been validated through numerical *** results indicate that the AF with OPA and S-AF with OPA have significantly better outage behavior and average throughput than AF and S-AF schemes *** also find that S-AF with OPA achieves a higher throughput,and hence lower outage probability than AF with OPA.

关键词： cognitive radio (CR) relay networks power allocation outage probability

Object Tracking and Tracing:Hidden Semi-Markov Model Based Probabilistic Location Determination

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Journal of shanghai Jiaotong university(science) 2011年第4期16卷 466-473页

作者：吴捷王东盛焕烨 department of computer {2. and engineering Shanghai Jiaotong University

The enhancement of radio frequency identification(RFID) technology to track and trace objects has attracted a lot of attention from the healthcare and the supply chain ***,RFID systems do not always function reliably under complex and variable deployment *** many cases,RFID systems provide only probabilistic observations of object ***,an approach to predict,record and track real world object states based upon probabilistic RFID observations is *** Markov model(HMM) has been used in the field of probabilistic location *** the inherent duration probability density of a state in HMM is exponential,which may be inappropriate for modeling of object location ***,in this paper,we put forward a hidden semi-Markov model(HSMM) based approach for probabilistic location determination. We evaluated its performance comparing with that of the HMM-based *** results show that the HSMM-based approach provides a more accurate determination of real world object states based on observation data.

关键词： object tracking and tracing hidden semi-Markov model(HSMM) probabilistic location determination radio frequency identification(RFID)

Dynamic Monte Carlo simulation of chain growth polymerization and its concentration effect

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science china Chemistry 2005年第5期48卷 459-465页

作者： Lü Wenqi & DING Jiandong Key Laboratory of Molecular engineering of Polymers, department of Macromolecular {2., Fudan University, shanghai 2.0433, china 1. Key Laboratory of Molecular engineering of Polymers Department of Macromolecular Science Fudan University 200433 Shanghai China

Free radical polymerization and living ion polymerization have been simulated via the dynamic Monte Carlo method with the bond-fluctuation model in this paper. The polymeriza-tion-related parameters such as conversion of monomers, degree of polymerization, average molecular weight and its distribution are obtained by statistics. The simulation outputs are con-sistent with the corresponding theoretical predictions. The scaling relationships of the coil size versus chain length are also confirmed at different volume fractions. Furthermore, the effect of diffusion on polymerization is revealed preliminarily in our simulation. Hence the simulation ap-proach has been proven to be feasible to investigate polymerization reactions with the advan-tages that configuration and diffusion of polymer chains can be examined together with polym-erization kinetics.

关键词： living ion polymerization free radical polymerization concentration effect configuration Monte Carlo simulation.

The optimization of replica distribution in the unstructured overlays

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science china(Information sciences) 2012年第3期55卷 714-722页

作者： FENG GuoFu1,2., LI WenZhong2. LU SangLu2. CHEN DaoXu2.& BUYYA Rajkumar3 1School of Information science, Nanjing Audit University, Nanjing 2.002., china 2.tate Key Laboratory of Novel Software {2., Nanjing University, Nanjing 2.0093, china 3department of computer science and Software engineering, The University of Melbourne, Victoria 3010, Australia 1. School of Information science Nanjing Audit University Nanjing 210029 China2. State Key Laboratory of Novel Software Technology Nanjing University Nanjing 210093 China3. Department of Computer Science and Software Engineering The University of Melbourne Victoria 3010 Australia

Replication is a widely used technique in unstructured overlays to improve content availability or system performance. A fundamental question often addressed by previous work focused on: how many replicas ought to be allocated for each data item given the fixed query rates and limited storage capability? In this paper, we have put forth two optimal replica distributions to achieve the highest success rate and the lowest message consumption. Especially, we have investigated the influence of item size on replica distribution. Our results show that Square-Root Replication, which is traditionally considered to be optimal, is not always the best choice. Our study offers a new deep understanding of resource managment in self-organized unstructured overlays.

关键词： unstructured overlay item size distribution query rate success rate expected search size

Structure and properties of SEBS/PP/OMMT nanocomposites

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Transactions of Nonferrous Metals Society of china 2006年第S2期 524-528页

作者： WANG Xia, PANG Shao-long, YANG Jun-he, YANG Fan department of Materials science and {2., shanghai Institute of technology, shanghai 2.02.5, china Chemistry department, east china Normal University, shanghai 2.0062. china

Nanocomposites based on styrene-b-(ethylene-co-butylenes)-b-styrene triblock copolymer(SEBS), polypropylene (PP) and organomontmorillonite (OMMT) were prepared using melt intercalation by a twin mill. The nanostructure of SEBS/PP/OMMT hybrids was characterized by X-ray diffractometry(XRD) and transmission electron microscopy(TEM). The d001 space of OMMT and SEBS/PP/OMMT hybrid increases from 1.30 nm to 3.52.nm and 4.06 nm, respectively which indicate, that the C16 and SEBS/PP could intercalate in the silicate layers and expand the basal spacing. The formation of intercalated structure was also confirmed by TEM. The results show that the individual silicates are well dispersed in the elastomer matrix. The glass transition temperature (tg) of PS block of SEBS was investigated by dynamic mechanical analysis (DMA). It is shown that there are remarkable enhancements in tg of PS block containing a small mass fraction of OMMT. tg of PS in SEBS of the nanocomposites has been increased about 39℃when containing 4% OMMT. The influence of OMMT on the dynamic storage moduli is temperature dependent. Below 50℃the SEBS/PP/OMMT composites with higher OMMT contents show higher dynamic storage moduli. OMMT has the function of reinforcing SEBS/PP elastomers. However, the influence of OMMT on the mechanical properties of the nanocomposites is not significant according to the tensile test and tear test.

关键词： SEBS polypropylene organomontmorillonite nanocomposites

A　Nonprecedence－based　Query　Schedule　Algorithm　on　Heterogeneous　Multiprocessor　System

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Journal of Systems engineering and Electronics 1995年第3期6卷 63-69页

作者： He Jun bang Dingxing & Zheng Weimin(department of computer {2. & technology,Tsinghua University, Beijing, 100084, china) department of computer {2. & technology Tsinghua University Beijing 100084 China

There has been a number of algorithms designed to handle intra-query or inter-query scheduling in multiprocessor-based parallel database system. They all have the assumption that the processorsare identical. But in some cases, such as shared nothing environment, this assumption would not be fullyvalid. In this paper we devise and evaluate a scheduling algorithm ELLIST to handle nonprecedence-basedheterogeneous malleable scheduling problem. It uses LLIST-NM as subroutine that handles nonmalleablescheduling without precedence and assuming the processors are identical. Even though the problem we considered is NP-hard in the strong sense, the schedule generated by our algorithm is seen experimentally toachieve results that are close to optimum when there are enough tasks to be scheduled.

关键词： Heterogeneous malleable scheduling Makespan Affinity

Stability of multiquadric quasi-interpolation to approximate high order derivatives

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science china Mathematics 2010年第4期53卷 985-992页

作者： MA LiMin 1,2.& WU ZongMin 1,1 shanghai Key Laboratory for Contemporary Applied Mathematics,School of Mathematical sciences,Fudan University,shanghai 2.0433,china 2.department of Information and computer science,Zhejiang Gongshang University,Hangzhou 310018,china 1. shanghai Key Laboratory for Contemporary Applied Mathematics School of Mathematical Sciences Fudan University Shanghai 200433 China2. Department of Information and Computer Science Zhejiang Gongshang University Hangzhou 310018 China

Numerical simulation of the high order derivatives based on the sampling data is an important and basic problem in numerical approximation,especially for solving the differential equations *** classical method is the divided difference ***,it has been shown strongly unstable in ***,it can only be used to simulate the lower order derivatives in *** simulate the high order derivatives,this paper suggests a new method using multiquadric *** stability of the multiquadric quasi-interpolation method is compared with the classical divided difference ***,some numerical examples are presented to confirm the theoretical *** theoretical results and numerical examples show that the multiquadric quasi-interpolation method is much stabler than the divided difference *** property shows that multiquadric quasi-interpolation method is an efficient tool to construct an approximation of high order derivatives based on scattered sampling data even with noise.

关键词： numerical differential radial basis functions (RBFs) Hardy’s multiquadric (MQ) quasiinterpolation divided difference method white noise expectation variance

Topology-aware Overlay Multicast over IP Multicast Networks

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Journal of shanghai Jiaotong university(science) 2008年第1期13卷 91-96页

作者：陈逍邵华钢汪为农 department of computer {2. and engineering Shanghai Jiaotong University Regional Network Center of east china

Most existing overlay multicast approaches refuse to consider any network layer support no matter whether it is available or not. This design principle greatly increases the complexity of the routing algorithms and makes the overlay topologies incompatible with the underlying network. To address these issues, topology-aware overlay multicast over IP multicast networks (TOMIMN) was proposed as a novel overlay multicast protocol, which exploits the cooperation between end-hosts and IP multicast routers to construct a topology-aware overlay tree. Through a little modification to protocol independent multicast sparse mode (PIM-SM), a multicast router is able to receive registration from nearby group members and redirect passing-by join requests to them. Due to the multicast router's support, TOMIMN organizes its group members into an overlay multicast tree efficiently, which matches the physical network topology well.

关键词： overlay networking network architecture overlay multicast

Explicit classes of permutation polynomials of F33m

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science china Mathematics 2009年第4期52卷 639-647页

作者： DING CunSheng1, XIANG Qing2. YUAN Jin3 & YUAN PingZhi4 1 department of computer {2. and engineering, The Hong Kong University of {2. and technology, Clearwater Bay, Kowloon, Hong Kong, china 2.department of Mathematical {2.s, University of Delaware, Newark, DE 19716, USA 3 department of Computing, Macquarie University, NSW 2.09, Australia 4 School of Mathematics, South china Normal University, Guangzhou 510631, china department of computer {2. and engineering The Hong Kong University of Science and Technology Hong Kong China department of Mathematical sciences University of Delaware Newark USA department of Computing Macquarie University Sydney Australia School of Mathematics South China Normal University Guangzhou China

Permutation polynomials have been an interesting subject of study for a long time and have applications in many areas of mathematics and engineering. However, only a small number of specific classes of permutation polynomials are known so far. In this paper, six classes of linearized permutation polynomials and six classes of nonlinearized permutation polynomials over F33m are presented. These polynomials have simple shapes, and they are related to planar functions.

关键词： permutation polynomials planar functions