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IEEE International Conference on Telecommunications and Malaysia communications (ICT-MICC)

作者： Chee Kyun Ng Borhanuddin Mohd Ali Sabira Khatun Sudhanshu Shekhar Jamuar Mahamod Ismail Department of Computer and Communication Systems Engineering Faculty of Engineering Universiti Putra Malaysia Malaysia Department of Electrical and Electronic Engineering Faculty of Engineering Universiti Putra Malaysia Malaysia Department of Electrical Electronic and System Engineering Faculty of Engineering Universiti Kebangsaan Malaysia Malaysia

Non-uniform traffics can severely degrade the performance of code division multiple access (CDMA) and space division multiple access (SDMA) cellular systems. In this paper, we propose a novel interference cancellation scheme by using the joint multiple access system from the merge of CDMA and SDMA systems to form dynamic space code multiple access (DSCMA). This multiple access system uses a modified version of large area synchronous (LAS) sequence called LAS even-ternary (LAS-ET) sequence to increase its duty ratio. This sequence also exhibits a region called interference free window (IFW) near zero delay time offset. In order to ensure that all the signal components drop within the IFW, a narrow beam with higher directivity smart antenna system is exploited. The size of IFW is adapted to the smart antenna half-power beamwidth using DSC algorithm. By using this algorithm the spectrum efficiency is further increased. Finally, all the interferences induced in non-uniform traffics can be dramatically reduced in DSCMA system and thus resulting in a higher system capacity.

关键词： Interference cancellation Multiaccess communication Multiple access interference Adaptive arrays systems engineering and theory Delay effects Antenna accessories Gold Intersymbol interference Antennas and propagation

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An Evaluation of Traceability Approaches to Support Software Evolution

An Evaluation of Traceability Approaches to Support Software...

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International Conference on Software engineering Advances (ICSEA)

作者： Siti Rochimah Wan M. N. Wan Kadir Abdul H. Abdullah Software Engineering Department Faculty of Computer Science and Information System Universiti Teknologi Malaysia Malaysia

Requirements traceability is becoming increasingly significant element in software engineering. It provides critical function in the development and maintenance of a software system. From the software evolution point of view, requirements traceability plays an important role in facilitating software evolution. Since the evolution is inevitable, a traceability approach must take as much as possible the important influencing aspects into account to the evolution processes in order to minimize the evolution efforts. This paper evaluates several recent traceability approaches published in literature with the focus on their contributions to software evolution. The evaluation results may be used as a basis for improving requirements traceability approaches that may simplify the software evolution tasks.

关键词： Software engineering Software systems Information retrieval Indexing Algorithm design and analysis computer science Information systems Software maintenance Resumes Software algorithms

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Map-based Adaptive Positioning in Wireless Sensor Networks

Map-based Adaptive Positioning in Wireless Sensor Networks

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International Symposium on Wireless Pervasive Computing (ISWPC)

作者： Ahmed A. Ahmed Hongchi Shi Yi Shang Department of Computer & System Engineering Faculty of Engineering Zagazig University Zagazig Egypt Department of Computer Science University of Missouri Columbia Columbia MO USA

Frequent localization in sensor networks may be needed due to the dynamically changing topology and the possible mobility of sensor nodes. We present a distributed adaptive localization method that we refer to as: map-based adaptive positioning (MAP). The main idea is to construct a relative local map at every node in the network, consisting of the node itself and its immediate neighbors, and merge the local maps together to form a global map. We consider two algorithms that can be used to estimate the relative local maps: multidimensional scaling (MDS) and semidefinite programming (SDP). The performance of these algorithms depend on two parameters: size of a local map, i.e., number of nodes, and the average connectivity of the node at the center of the local map and its 1-hop neighbors. We use machine learning to adaptively select the appropriate algorithm to estimate the relative local maps. Simulation results show that MAP outperforms both MDS and SDP, with better improvement for networks with less uniform node deployment.

关键词： Wireless sensor networks Multidimensional systems Network topology Sensor systems Machine learning algorithms computer networks systems engineering and theory computer science Machine learning Instruments

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Reduced-Order Proper H_(infinity) Controllers for Descriptor systems: Existence Conditions and LMI-Based Design Algorithms

Reduced-Order Proper H_(infinity) Controllers for Descriptor...

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Proceedings of the 46th IEEE Conference on Decision and Control, Pages 3220-3677

作者： Xin Xin Shinji Hara Masahiro Kaneda Department of Communication Engineering Faculty of Computer Science and System Engineering Okayama Prefectural University Soja Okayama Japan Department of Information Physics and Computing Graduate School of Information Science and Technology University of Tokyo Bunkyo Tokyo Japan

In this paper, we present a new approach to investigate the existence and design of reduced-order proper H_(infinity) controllers that provide the same level of performance as that of full-order controllers. By revealing some special features of the LMI-based solvability conditions for the H_(infinity) control problem for descriptor systems, we obtain a refined bound on the order of H_(infinity) controllers, which is independent of (invariant under the allowed transformations on) a descriptor realization of the generalized plant. Moreover, we provide two LMI-based algorithms to design the reduced-order controllers and demonstrate the validity of the presented theoretical results via two numerical examples. This paper not only extends in a satisfying way the results on reduced-order H_(infinity) controllers for state-space systems to descriptor systems, but also provides insight into the mechanism by which the order of H_(infinity) controllers for descriptor systems can be reduced through a consideration of the unstable finite zeros or infinite zeros.

关键词： Control systems Algorithm design and analysis USA Councils Application software computer science systems engineering and theory Physics computing Information science Filtering theory

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Translocation and insertion of an amphiphilic polymer

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Physical Review E 2007年第1期76卷 011801-011801页

作者： Satoshi Tsuchiya Akihiko Matsuyama Department of Bioscience and Bioinformatics Faculty of Computer Science and System Engineering Kyushu Institute of Technology Kawazu 680-4 Iizuka Fukuoka 820-8502 Japan.

Translocation of amphiphilic polymers (random and block copolymers), consisting of hydrophilic and hydrophobic monomers, threading a pore is studied by using a three-dimensional dynamic Monte Carlo simulation. We find that there is a “translocation-insertion” threshold in the fraction of hydrophobic monomers on an amphiphilic polymer. The translocation time is given by simple scaling laws and increases with increasing the fraction of hydrophobic monomers.

关键词： Block copolymers

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Spectral amplitude coding OCDMA using AND subtraction technique

Spectral amplitude coding OCDMA using AND subtraction techni...

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IEEE International Conference on Telecommunications and Malaysia communications (ICT-MICC)

作者： S.A. Aljunid M. Othman N.S.M. Shah M.D.A. Samad R.K.Z. Sahabudin M.K. Abdullah School of Computer & Communication Engineering Universiti Malaysia Pedis Kangar Perlis Malaysia Department of Communication Engineering Faculty of Electrical and Electronic Engineering Universiti Tun Hussein Onn Malaysia Batu Pahat Johor Malaysia Photonics Laboratory Department of Computer and Communication System Faculty of Engineering Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia

A new detection scheme, namely AND subtraction technique is proposed and presented in this paper. The theory is being elaborated and the calculated and simulation results have been done by comparing AND subtraction technique against complementary subtraction technique by using DW code. In this paper we have proved that AND subtraction technique gives better bit error rate (BER) performance than complementary subtraction technique.

关键词： Subtraction techniques Multiple access interference Phase detection Optical computing Bit error rate Optical receivers Optical transmitters Multiaccess communication Telecommunication computing Photonics

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Performance of the optical spectrum CDMA systems in FTTH access network

Performance of the optical spectrum CDMA systems in FTTH acc...

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IEEE International Conference on Telecommunications and Malaysia communications (ICT-MICC)

作者： M. Othman N.S.M. Shah N.A. Cholan R. Talib M.D.A. Samad S.A. Aljunid M.K. Abdullah Department of Communication Engineering Faculty of Electrical and Electronic Engineering Universiti Tun Hussein Onn Malaysia Batu Pahat Johor Malaysia Photonics Laboratory Department of Computer and Communication System Faculty of Engineering Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia School of Computer & Communication Engineering Universiti Malaysia Pedis Kangar Perlis Malaysia

Double Weight (DW) code is presented here to support fiber-to-the-home (FTTH) access network in point-to-multipoint (P2MP) applications. This code with basic fixed weight of 2 possess ideal cross correlation properties, that are important characteristics in spectral encoding OCDMA system since these can eliminate multiple user interference and can reduce noise. The performance of DW code against Hadamard code is compared through simulation by using Optisystem version 2.2. The performances were characterized through bit error rate (BER) against number of user for two network designs. One is without erbium doped fiber amplifier (EDFA) and another one is with the EDFA for P2MP network. It is found that DW code is better than Hadamard code for all simulation results at bit rates of 622 Mbps, 1.25 Gbps and 2.5 Gbps.

关键词： Optical fiber networks Multiaccess communication Optical fiber subscriber loops Error correction Error correction codes Bit error rate Erbium-doped fiber amplifier Encoding Interference elimination Noise reduction

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An enhanced IPv6 Anycast routing protocol using Protocol Independent Multicast-Sparse Mode (PIM-SM)

An enhanced IPv6 Anycast routing protocol using Protocol Ind...

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IEEE International Conference on Telecommunications and Malaysia communications (ICT-MICC)

作者： Aus M. Sulaiman Borhanuddin Mohd. Ali Sabira Khatun Gopakumar Kurup Department of Computer and Communication System Engineering Faculty of Engineering Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia MIMOS Berhad Kuala Lumpur Malaysia

Although the demands for finding an economical routing protocol that provides the service to the clients in shortest time and least cost are increasing. IPv6 Anycast still has a lot of issues and problems in practical applications. One of the problems is that IPv6 Anycast still does not have its own standard protocol. In this paper we develop a new Anycast routing protocol by modifying the existing multicast routing protocol because anycast and multicast have many similar properties. Protocol Independent Multicast-Sparse Mode (PIM-SM) is chosen as a basis to design a new anycast routing protocol. We next improve the design by considering the status (free or busy) of the anycast receivers as an important factor in our design. Besides the metric value of the receiver, we propose a new variable in the routing table called BMF (Best Metric Factor).

关键词： Routing protocols Multicast protocols Network servers Costs Unicast Web server Telecommunication computing systems engineering and theory MIMO Mechanical factors

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Router enhanced NAT method for peer-to-peer network

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Ruan Jian Xue Bao/Journal of Software 2007年第SUPPL.期18卷 88-94页

作者： Zhang, Jian-Wei Pi, Ren-Jie Zhan, Xiao-Su Guo, Yun-Fei National Digital Switch System Engineering and Technological Research Center Zhengzhou 450002 China Department of Computer Science Beijing University of Posts and Telecommunications Beijing 100876 China Department of Computer and Communication Zhengzhou University of Light Industry Zhengzhou 450002 China Department of Electronic Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

The deployment of symmetric NAT makes the communication between hosts in a peer-to-peer application very difficult, which needs many relay node to provide NAT traversal service. Traditional relay nodes are all server hosts lie in the edge of network. To reduce the duplicate traffic and excess router load caused by server relaying, a UDP switch based router enhanced NAT method is proposed in this paper, which can resolve the bottleneck of network bandwidth by enhance router function independently.

关键词： Routers

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Designing a Generic Collaborative Working Environment

Designing a Generic Collaborative Working Environment

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IEEE International Conference on Web Services (ICWS)

作者： M. A. Martinez-Carreras A. Ruiz-Martinez F. Gomez-Skarmeta W. Prinz Department of Information and Communication Engineering Faculty of Computer Science Murcia Spain Fraunhofer Institut FIT Saint Augustine USA

Groupware provides an essential support for the maintenance of knowledge management in many organizations. Accordingly, the use of groupware systems has become widespread. However, still some problems regarding the way in which business process are implemented exist, because they require the communication between several of these groupware systems to fulfill all required objectives in the organization. For that reason, interoperability issues have taken a vital role in the business sector. In this area, one of the leading technologies is the Web service standard. In this paper we describe the design of a generic collaborative working environment to provide the basis for allowing interoperability with several groupware systems. We also reflect how Web services technologies are used in the design of this environment.

关键词： Collaborative work Collaborative software International collaboration Web services Service oriented architecture Business communication Knowledge management Collaborative tools Design engineering Knowledge engineering

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