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Performance analysis of hybrid SCM/OSCDM system using the Khazani-Syed (KS) code

WSEAS Transactions on communications 2008年第11期7卷 1066-1074页

作者： Sahbudin, R.K.Z. Abdullah, M.K. Department of Computer and Communication System Engineering Faculty of Engineering University Putra Malaysia 43400 Serdang Selangor Malaysia

This paper proposes a hybrid subcarrier multiplexing/optical spectrum code division multiplexing (SCM/OSCDM) system for the purpose of combining the advantages of both techniques. Optical spectrum code division multiple access (OSCDMA) is one of the multiplexing techniques that is becoming popular because of the flexibility in the allocation of channels, ability to operate asynchronously, enhanced privacy and increased capacity in bursty nature networks. On the other hand, subcarrier multiplexing (SCM) technique is able to enhance the channel data rate of OSCDMA systems. The system utilizes a new unified code construction named KS (Khazani-Syed) code based on the Double Weight (DW) and Modified Double Weight (MDW) codes. This paper also presents a new detection technique called Spectral Direct Decoding (SDD) detection technique for the OSCDM. SDD is effective in rejecting the unwanted signals that interfere with the wanted signals. This results in reduced receiver complexity and improved the performance of the hybrid system significantly.

关键词： Multiple access interference

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Effectiveness of server load estimation by using request file size for web server clusters

IEEJ Transactions on Electronics, Information and Systems

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IEEJ Transactions on Electronics, Information and systems 2008年第10期128卷 1543-1549+5页

作者： Satake, Shinsuke Inai, Hiroshi Arai, Tsuyoshi Department of Communication Engineering Faculty of Computer Science and System Engineering Okayama Prefectural University 111 Kuboki Soja-shi Okayama 719-1197 Japan

There have been proposed several dynamic load-balancing methods for web server clusters. In order to realize an effective load-balancing, they have required an almost real-time server load information which could be obtained from an observation of client-server interactions or a frequent polling from the load-balancer (dispatcher) to each server. However the observation provides an indirect server load information and the polling interval produces a time-lag. To overcome that problem, this paper proposes a load-balancing method based on a server load estimation. Under an employment of our method, the load-balancer selects an estimated least-loaded server, and then assigns the arriving request to that server. The estimation is based on a fact that the file transfer delay is proportional to the file size. The fact makes it possible to estimate each server load from the last request assigned time and the file size. From a performance comparison with the previously proposed methods, our method can realize an effective load balancing for web server clusters. © 2008 The Institute of Electrical Engineers of Japan.

关键词： Web services

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Maximizing the energy efficiency in MS-MAC using a dynamic approach

Maximizing the energy efficiency in MS-MAC using a dynamic a...

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IEEE 2008 6th National Conference on Telecommunication Technologies and IEEE 2008 2nd Malaysia Conference on Photonics, NCTT-MCP 2008

作者： Mouzehkesh, Nesa Noordin, Nor K. Rasid, Mohd Fadlee A. Department of Computer and Communication System Engineering Faculty of Engineering University Putra Malaysia 43400 Serdang Selangor Malaysia

ISBN: (纸本)9781424422159

There has been an intensive research on a good MAC protocol design for wireless sensor networks with stationary nodes in which they all aim at making some wise trade offs between the network performance parameters and energy efficiency as the main design principle in WSN. But almost none of these MAC protocols, except a few, have addressed mobility in their structure which poses many new challenges to the MAC concept in wireless sensor networks. This paper collaborates on a little enhancement on MS-MAC, a mobility adaptive MAC protocol, in WSN. The MS-MAC protocol handles mobility by proactively increasing the frequency of the Sync period inside the active zone. However this increase is based on a static approach which forms the active zone with a constant value of R and appears to be problematic when the border node becomes mobile as well. In this paper we aim at optimizing the value of R by dynamically increasing or decreasing it according to the distance the border node takes from the border region. We expect that this dynamic approach increases the energy efficiency by preventing the nodes inside the virtual clusters going into the active zone unnecessarily but yet at the cost of an increased latency. © 2008 IEEE.

关键词： Energy efficiency

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Data analysis of road pavement density measurements using Ground Penetrating Radar (GPR)

Data analysis of road pavement density measurements using Gr...

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International Conference on computer and communication engineering 2008, ICCCE08: Global Links for Human Development

作者： Raja Abdullah, R.S.A. Mohd Shafri, Helmi Zulhaidi Bin Roslee, Mardeni Bin Department of Computer and Communication System Faculty of Engineering Universiti Putra Malaysia Department of Civil Engineering Faculty of Engineering Universiti Putra Malaysia

ISBN: (纸本)9781424416929

This work describes an analysis of Ground Penetrating Radar (GPR) measurements at frequency range of 1.7-2.6 GHz to get a relationship between attenuation and density for nine road pavements slabs with different densities. There are about two different frequencies had been tried. The method is simple, fast, contact less and accurate way to determine the density of road pavement. The most important parameter that used in this project is density where it can be used to determine the compressive strength of road pavement. In laboratory, the measurement system consists of a signal generator (250 kHz-3GHz) as a source, spectrum analyzer (100Hz-8GHz), directional coupler with adapter and horn antenna. The first part of the measurement system setup is to determine the amplitude of transmitted wave (received signal strength). A few of received signal strength and attenuation for nine pavement slab samples were taken at two different frequencies. The GPR mixture model has been used to produce the simulation data and has been compared with measurement data. An instantaneous method for measuring the density of road pavement in wave propagation was developed by using microwave transmission/ reflection technique and free space method at two frequencies. The MATLAB software is used to analyze the measurement and simulation data and also for the graphs comparisons. The relative error between measurement and simulation were calculated. The results from the GPR measurement were used and were elaborated in data statistical analysis. ©2008 IEEE.

关键词： Horn antennas

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Color Effect on the Face Recognition with Spatial Resolution Constraints

Color Effect on the Face Recognition with Spatial Resolution...

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IEEE International Symposium on Multimedia

作者： Choi, Jae Young Yang, Seungji Ro, Yong Man Plataniotis, Konstantinos N. Image and Video System Laboratory Information and Communication University South Korea Department of Electrical and Computer Engineering University of Toronto Canada

ISBN: (纸本)9781424440894

In the practical face recognition (FR) applications, low-resolution faces (20 x 20 pixels or less) are commonly encountered and negatively impact on reliable performance. To overcome low-resolution face problem, we show that face color can significantly improve the performance compared to intensity-based features. The contribution of this paper is twofold. First, a new metric called 'variation ratio gain' (VRG) is proposed to theoretically prove the significance of color effect on low-resolution faces. Second, we conduct extensive performance comparison studies. In particular, 3,192 color facial images corresponding to 341 subjects, collected from three standard CMU PIE, FERET, and XM2VTSDB face databases, were used to perform comparative studies of color effect on various face resolutions. Experimental results verified that face color feature improves the degraded recognition rate due to low-resolution faces by at least an order of magnitude over intensity-based features.

关键词： Color face recognition Face resolution Identification Variation ratio gain Verification

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Field test validation of optimized ground penetrating radar (GPR) mixture model at frequency range 1.7 GHz to 2.6 GHz

Field test validation of optimized ground penetrating radar ...

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2008 IEEE International RF and Microwave Conference, RFM 2008

作者： Mardeni, R. Raja Abdullah, R.S.A. Mohd Shafri, Helmi Zulhaidi Department of Computer and Communication System Faculty of Engineering Universiti Putra Malaysia Malaysia Department of Civil Engineering Faculty of Engineering Universiti Putra Malaysia Malaysia

ISBN: (纸本)9781424428663

This paper presents the validation of optimized GPR mixture model based on the microwave nondestructive free space method in order to determine the density of road pavement. Density is an important parameter to determine the compressive strength of road pavement for road user safety. The attenuation is a major factor for gathering the density of road pavement predictly. A few of measured attenuation were taken at nine road pavement slab samples in laboratory. The GPR mixture model has been used to produce the simulation data to predict the attenuation. The comparison results between measurement and simulation were investigated. The best performance of GPR mixture model was selected in the optimization technique due to the smallest mean error. An improved attenuation formula or optimized GPR model was obtained from the optimization technique. The validation at field test had been conducted in order to see the performance of optimized GPR model. © 2008 IEEE.

关键词： Compressive strength

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Application of a fuzzy C-mean algorithm for pulse waveform analysis in patients with myocardial ischemia

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International Journal of Electrical engineering 2008年第5期15卷 399-407页

作者： Liu, Shing-Hong Chang, Kang-Ming Chen, Jian-Jung Tang, Kuo-Tai Department of Computer Science and Information Engineering Chaoyang University of Technology Taichung Taiwan Department of Computer and Communication Asia University Taichung Taiwan Department of Chinese Medicine Taichung Tzu Chi General Hospital Taichung Taiwan Department of Management Information System National Chengchi University Taipei Taiwan

Previous noninvasive measurements of the pulse waveform of the radial artery have not employed standard positioning procedures. Here we propose a new three-axis mechanism for simultaneously measuring the arterial diameter changed waveform (ADCW) and the pressure pulse waveform (PPW), and a standard positioning procedure for detecting the optimal site in which the PPW may be accurately recorded. A modified fuzzy c-mean algorithm was used to diagnosis myocardial ischemia symptoms in 34 elderly subjects with the PPW of radial artery. The exercise electrocardiogram was used as a reference to compare between individuals with and without myocardial ischemia. The first three harmonics of the Fourier series of PPW in the patients with myocardial ischemia are significantly different from those in the normal subjects. The harmonics of the Fourier series of PPW are then fed into a modified fuzzy c-means algorithm, resulting in a sensitivity of 68% and specificity of 100% in identifying the patients with myocardial ischemia from the normal subjects.

关键词： Fourier series

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Face annotation for personal photos using context-assisted face recognition

Face annotation for personal photos using context-assisted f...

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1st International ACM Conference on Multimedia Information Retrieval, MIR2008, Co-located with the 2008 ACM International Conference on Multimedia, MM'08

作者： Choi, Jae Young Yang, Seungji Ro, Yong Man Plataniotis, Konstantinos N. Image and Video System Laboratory Information and Communication University Korea Republic of Department of Electrical and Computer Engineering University of Toronto Canada

ISBN: (纸本)9781605583129

Face annotation for personal photos has a number of potential applications in Multimedia Information Retrieval (MIR). We propose a novel face annotation method that systematically combines contextual information of photos with traditional Face Recognition (FR) technologies. To overcome the limitations of conventional FR-based annotation approaches, situation and person clustering methods are proposed based on context of personal photos. By relying on the proposed clustering methods, multiple facial images that belong to the same person are applied to subspace FR methods. This allows traditional FR methods to take advantages of feature- or measurement-level fusion strategies for automatic annotation of faces on personal photos. The effectiveness of the proposed method was successfully tested on 1,120 personal photos selected from standard MPEG-7 Visual Core Experiment 3 (VCE-3). Extensive experimental results showed that the proposed method improves annotation accuracy by at least an order of magnitude, compared with conventional FR-based approaches. Copyright 2008 ACM.

关键词： Face recognition

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Simulating the effect of team management on its performance

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Journal of Harbin Institute of Technology (New Series) 2008年第SUPPL.期15卷 256-261页

作者： Yang, Chao Jiang, Bin Yamada, Takashi Terano, Takao Department of Computational Intelligence and System Science Interdisciplinary Graduate School of Science and Engineering Tokyo Institute of Technology Yokohama 226-8502 Japan College of Computer and Communication Hunan University Changsha 410082 China

This paper proposes an agent-based simulation model to analyze how team management affects performances of the team with three fundamental parameters: team size, skill combination among team members and task structure. The results confirmed are as follows: first, communication cost increases when the team size grows, and team-workers benefit from a right team size to obtain higher productivity;second, each team member has more chances to receive tasks that he/she is good at and then strengthen this skill ability by accumulative experience;third, a team shows more efficiency and robustness under a task environment where both workload and sub-task variety get to a balanceable distribution in a long term.

关键词： Project management

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A framework of authentic post-issuance program modification for multi-application smart cards

A framework of authentic post-issuance program modification ...

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2008 International Conference on Wireless Networks, ICWN 2008

作者： Uddin, Mohammad Mesbah Zabir, Salahuddin Muhammad Salim Nohara, Yasunobu Yasuura, Hiroto Department of Computer Science and Communication Engineering Kyushu University Fukuoka Japan System LSI Research Center Kyushu University Fukuoka Japan

ISBN: (纸本)1601320914

Authentic program modification is very important for a multi-application smart card system since applications in the system are realized after the issuance of the smart card. In this paper, we propose a framework for such authentic program modification. In our framework, before issuing a smart card to an individual, the card issuer stores a unique long bit string called PID on the card. From the PID, unique substrings (subPIDs) are generated and used for different authentication purposes. The program modification protocol utilizes the subPIDs along with a one-way hash function and a pseudo random number generator function to verify the identity of the parties and the authenticity of the program. Our proposed framework provides a simple and practical solution to the program modification problem by avoiding direct interaction between the card holder and the issuer. In addition, use of hash functions makes the implementation cost of smart cards low.

关键词： Smart cards

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