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2009 5th International Conference on MEMS NANO, and Smart systems, ICMENS 2009

作者： Ab-Rahman, Mohammad Syuhaimi Hassan, Mazen R. Department of Electrical Electronic and Systems Engineering Faculty of Engineering and Built Environment Computer and Network Security Research Group 43600 Bangi Selangor Malaysia

ISBN: (纸本)9780769539386

In this paper, the effect of external optical feedback (EOF) on the turn-on time delay (ton) of uncooled semiconductor laser diode (SLD) is investigated theoretically. The effects temperature of operation (T) and EOF on ton are calculated according to their effect on threshold carrier density (Nth). The temperature dependence (TD) of Nth is calculated according to the TD of laser cavity parameters and not by the well-known Parkove relationship. Simulation results show that ton increases as T increases due to increasing of Nth. In addition, ton decreases as external reflectivity (rext) increases when the phase of reflected light is coherent. While at incoherent reflected light, ton increases sharply around specified value of r ext where this leads to inoperable case for SLD. © 2009 IEEE.

关键词： Time delay

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Minimizing rate distortion in peer-to-peer video streaming

Minimizing rate distortion in peer-to-peer video streaming

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2009 6th IEEE Consumer Communications and networking Conference, CCNC 2009

作者： Hossain, Tareq Cui, Yi Xue, Yuan Vanderbilt Advanced NETwork Systems Laboratory Department of Electrical Engineering and Computer Science Vanderbilt University Nashville TN 37212 United States

ISBN: (纸本)9781424423095

This paper addresses the problem of optimal rate allocation for video stream in peer-to-peer networks. We present a distributed rate allocation algorithm with the goal of minimizing the total video distortion among peers receiving the same video. The scheme assumes that video streams can be transcoded/re-quantized at intermediate peers. We deploy a double pricing solution that simultaneously incorporates the network and the relay constraints in the peer-to-peer network and compare it with a single pricing solution where the relay constraint is applied only after all the communicating peers converge to optimality. We combine our solution with two video adaptation techniques: transcoding using x264 and scalable coding using H.264 SVC (scalable video coding) extension. Our experiment shows that the double pricing solution consistently achieves a smaller aggregate distortion for all peers over the single pricing solution. ©2009 IEEE.

关键词： Peer to peer networks

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On the optimality of layered video streaming rate in a P2P mesh network

On the optimality of layered video streaming rate in a P2P m...

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2009 18th International Conference on computer Communications and networks, ICCCN 2009

ISBN: (纸本)9781424445813

Layered streaming is an effective solution to address receiver heterogeneity in a Peer-to-peer (P2P) network. This paper addresses the problem of rate allocation for layered video stream in p2p mesh networks. We present a distributed rate allocation algorithm that achieves close to optimal layer allocation among peers receiving the same video. We use load balancing technique that evenly distributes layer requests to a parent peer. Weight based layer allocation technique ensures that a child peer with higher children receives higher priority in servicing layer allocation request from its parents. Results show that for up to seven layers streamed by a server, the algorithm maintains a layerdelivery ratio of 88% or more among all peers in a network. ©2009 IEEE.

关键词： Video streaming

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Effect of fabrication parameters on luminescent properties of ZnS:Mn nanocrystals

Effect of fabrication parameters on luminescent properties o...

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2009 Asia Communications and Photonics Conference and Exhibition, ACP 2009

作者： Shaari, Sahbudin Ab-Rahman, Mohd Syuhaimi Arif, Noor Azie Azura Mohd Institute of Micro Engineering and Nanoelectronics Universiti Kebangsaan Malaysia 43600 UKM Bangi Selangor Malaysia Computer and Network Security Research Group Department of Electrical Electronic and Systems Engineering 43600 UKM Bangi Selangor Malaysia

ISBN: (纸本)9781557528773

In this work, we mainly focused on the luminescence properties of ZnS:Mn nanocrystals. Various samples of ZnS:Mn have been characterized at different doping concentration, annealing temperature, speed and rotation time. Luminescent intensity increased with higher annealing temperature, doping concentration but decreased with higher speed and rotation time during stirring process. ©2009 Optical Society of America.

关键词： Zinc sulfide

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Fault-Tolerant Bit-Parallel Multiplier for Polynomial Basis of GF（2^m）

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Journal of Electronic Science and Technology of China 2009年第4期7卷 343-347页

作者： Chiou-Yng Lee Pramod Kumar Meher Chia-Chen Fan Computer Information and Network Engineering Lunghwa University of Science and Technology Department of Communication Systems Institute for Infocomm Research

Novel fault-tolerant architectures for bit-parallel polynomial basis multiplier over GF（2^m）, which can correct the erroneous outputs using linear code, are presented. A parity prediction circuit based on the code generator polynomial that leads lower space overhead has been designed. For bit-parallel architectures, the Moreover, there is incorporation of space overhead only marginal time error-correction is about 11%. overhead due to capability that amounts to 3.5% in case of the bit-parallel multiplier. Unlike the existing concurrent error correction （CEC） multipliers or triple modular redundancy （TMR） techniques for single error correction, the proposed architectures have multiple error-correcting capabilities.

关键词： Fault tolerant system finite field parity prediction.

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Thermal noise effect on receiver sensitivity in FTTH customer access network - Simulation approach

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Journal of Optical Communications 2009年第2期30卷 95-98页

作者： Ab-Rahman, Mohammad Syuhaimi Ng, Boonchuan Safnal, Mohd. Hadi Guna Computer and Network Security Research Group Department of Electrical Electronics and Systems Engineering Faculty of Engineering and Built Environment 43600 UKM Bangi Selangor Malaysia

Thermal noise is generated naturally by thermal agitation of electron in a conductor commonly found in optoelectronic (O/E) device. In spite of the optical medium is totally immune to noises but it is not exception to occur in receiver parts. In communication, thermal noises have major influenced to the quality of receiver. It is directly proportional to the resistance and temperature. The lower the thermal noise the higher and expensive is this receiver sensitivity. The paper starts comprehensive study on thermal noise effect to the network performance in terms of bit-error rate (BER), maximum Q-factor, eye height, and maximum distance. Fiber-to-the-home (FTTH) network is used as a test field to study the impact of two different values of thermal noise to the network parameters. We use the receiver sensitivity fixed at -22 dBm to study and analyze the parameters. The Opti-System simulation is used to obtain the desired research objective.

关键词： Q factor measurement

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Matlab-based system for centralized monitoring and self restoration against fiber fault in FTTH

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World Academy of Science, engineering and Technology 2009年 38卷 873-877页

作者： Ab-Rahman, Mohammad Syuhaimi Ng, Boonchuan Jumari, Kasmiran Computer and Network Security Research Group Department of Electrical Electronics and Systems Engineering Faculty of Engineering and Built Environment 43600 UKM Bangi Selangor Malaysia

This paper presented a MATLAB-based system named Smart Access network Testing, Analyzing and Database (SANTAD), purposely for in-service transmission surveillance and self restoration against fiber fault in fiber-to-the-home (FTTH) access network. The developed program will be installed with optical line terminal (OLT) at central office (CO) to monitor the status and detect any fiber fault that occurs in FTTH downwardly from CO towards residential customer locations. SANTAD is interfaced with optical time domain reflectometer (OTDR) to accumulate every network testing result to be displayed on a single computer screen for further analysis. This program will identify and present the parameters of each optical fiber line such as the line's status either in working or nonworking condition, magnitude of decreasing at each point, failure location, and other details as shown in the OTDR's screen. The failure status will be delivered to field engineers for promptly actions, meanwhile the failure line will be diverted to protection line to ensure the traffic flow continuously. This approach has a bright prospect to improve the survivability and reliability as well as increase the efficiency and monitoring capabilities in FTTH. © 2009 ***.

关键词： Fiber to the x

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Learning the Point Gathering Task Using Shared Value Function In Mobile Robots

Learning the Point Gathering Task Using Shared Value Functio...

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International Conference on Advanced computer Control, ICACC

作者： Sriram Raghavan S.V. Raghavan Network Systems Laboratory Department of Computer Science and Engineering Indian Institute of Technology Madras India Network Systems Laboratory Dept. of Computer Science and Engg. Indian Institute of Technology Madras

Managing the actions of several agents to perform tasks which require coordination and cooperation pose significant research challenges. One such challenge is to synchronize the agentspsila view of the system to help them take the dasiarightpsila actions. In this paper, we propose an algorithm called MRCPG (Mobile Robot Coordination Point Gathering Algorithm) for coordinating the actions of a team of mobile robots. The aim is to gather these robots at a particular location in a 2-dimensional plane which is determined during execution. The robots are randomly deployed in the plane and they achieve the goal by communicating periodically. In addition, we impose a reinforcement learning framework and the robots learn a shared value function (SVF) based on scalar rewards received. The SVF is used to select the best possible action in each state until at least one robot reaches the goal. Then a reach-distance heuristic is used to direct the remaining robots to the goal. The algorithm was analyzed through simulations for up to 5 robots and the analysis indicates that communication helped robots perform significantly faster than when they acted independently - measured using the path-length of the first robot to reach the goal as the metric. We also observed that increasing team size enhances the effect of communication and hastens task completion.

关键词： Mobile robots Robot kinematics Algorithm design and analysis Performance analysis Intelligent robots Laboratories computer science Inference algorithms Learning Robotic assembly

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Infrared Thermography Based Image Construction for Bio-Medical Applications

Infrared Thermography Based Image Construction for Bio-Medic...

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The 3rd International Conference on Bioinformatics and Biomedical engineering(iCBBE 2009)(第三届生物信息与生物医学工程国际会议)

作者： V.Umadevi S.V.Raghavan Network Systems Laboratory Department of Computer Science and Engineering Indian Institute of Technology Madras Chennai-600036 India

Scanning and imaging techniques, when applied to medicine, are helpful in diagnosis of some critical illnesses that affect human beings. Imaging techniques use the electromagnetic spectrum for the construction of internal anatomy, visibility of organs, and for detection of tumors and other such anomalies. Infrared Radiation (IR), which is part of the electromagnetic spectrum, is a potential alternative in medical imaging, as it is non-invasive and non-ionizing. Thermal (or infrared) radiation emission from human body will be higher around the regions where an anomaly such as a tumor is present inside the body - essentially due to increased cell related activity. In the work reported here we use the IR energy measurement from the body surface to contour a tumor inside. As the radiation and the attendant attenuation are non-linear, it is quite involved to interpret the IR energy measured outside the body. However, we attempt to develop an inverse function to estimate parameters of tumor. We use some strong assumptions (can be described as trivializing the clinical value by medical scientists and practitioners!) to get an exact solution to the “tumor contouring” problem and present a framework called ITBIC as a solution.

关键词： tumor contour thermography framework

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Improved infrared thermography based image construction for biomedical applications using Markov Chain monte carlo method

Improved infrared thermography based image construction for ...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： V. Umadevi S. Suresh S. V. Raghavan Network Systems Laboratory Department of Computer Science and Engineering IIT Madras Chennai India Department of Mechanical Engineering IIT Madras Chennai India

Breast Thermography is one of the scanning techniques used for breast cancer detection. Looking at breast thermal image it is difficult to interpret parameters of tumor such as depth, size and location which are useful for diagnosis and treatment of breast cancer. In our previous work (ITBIC) we proposed a framework for estimation of tumor size using clever algorithms and the radiative heat transfer model. In this paper, we expand it to incorporate the more realistic Pennes bio-heat transfer model and Markov chain Monte Carlo (MCMC) method, and analyze it's performance in terms of computational speed, accuracy, robustness against noisy inputs, ability to make use of prior information and ability to estimate multiple parameters simultaneously. We discuss the influence of various parameters used in its implementation. We apply this method on clinical data and extract reliable results for the first time using breast thermography.

关键词： Infrared imaging Biomedical optical imaging Breast cancer Breast neoplasms Cancer detection Heat transfer Monte Carlo methods Information analysis Performance analysis Robustness

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