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Enhancing /spl epsiv/-approximation algorithms with the optimal linear scaling factor

IEEE Transactions on Communications 2006年第9期54卷 1624-1632页

作者： Gang Cheng N. Ansari Li Zhu VPI Systems Inc. Holmdel NJ USA Advanced Networking Laboratory Electrical and Computer Engineering Department New Jersey Institute of Technology Newark NJ USA

Finding a least-cost path subject to a delay constraint in a network is an NP-complete problem and has been extensively studied. Many works reported in the literature tackle this problem by using epsiv-approximation schemes and scaling techniques, i.e., by mapping link costs into integers or at least discrete numbers, a solution which satisfies the delay constraint and has a cost within a factor of the optimal one, that can be computed with pseudopolynomial computational complexity. In this paper, having observed that the computational complexities of the epsiv-approximation algorithms using the linear scaling technique are linearly proportional to the linear scaling factor, we investigate the issue of finding the optimal (the smallest) linear scaling factor to reduce the computational complexities, and propose two algorithms, the optimal linear scaling algorithm (OLSA) and the transformed OLSA. We analytically show that the computational complexities of our proposed algorithms are very low, as compared with those of epsiv-approximation algorithms. Therefore, incorporating the two algorithms can enhance the epsiv-approximation algorithms by granting them a practically important capability: self-adaptively picking the optimal linear scaling factors in different networks. As such, epsiv-approximation algorithms become more flexible and efficient

关键词： Routing Computational complexity Delay Cost function Laboratories computer networks NP-complete problem Algorithm design and analysis Telecommunication traffic

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Service System Resource Management Based on a Tracked Layered Performance Model

Service System Resource Management Based on a Tracked Layere...

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International Conference on Autonomic Computing (ICAC)

作者： M. Woodside Tao Zheng M. Litoiu Department of Systems and Computer Engineering Carleton University Ottawa Canada Centrefor Advanced Studies IBM Toronto Software Laboratory Canada

Autonomic computer systems adapt themselves to cope with changes in the operating conditions and to meet the service-level agreements with a minimum of resources. Changes in operating conditions include hardware and software failures, load variation and variations in user interaction with the system. The self adaptation can be achieved by tuning the software, balancing the load or through hardware provisioning. This paper investigates a feed-forward adaptation scheme in which tuning and provisioning decisions are based on a dynamic predictive performance model of the system and the software. The model consists of a layered queuing network whose parameters are tuned by tracking the system with an Extended Kalman Filter. An optimization algorithm searches the system configuration space by using the predictive performance model to evaluate every configuration.

关键词： Resource management Predictive models Feedforward systems Hardware Quality of service Software performance Software systems Feedback control Web server Yarn

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Supervisory signal transmission in distributed Raman amplifiers

Supervisory signal transmission in distributed Raman amplifi...

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IEEE International Workshop on Electronic Design, Test and Applications (DELTA)

作者： Lau Bei Yer V. Kalavally M. Premaratne Tin Win Department of Electrical and Computer Systems Engineering School of Engineering Monash University Malaysia Selangor Malaysia Department of Electrical and Computer Systems School of Engineering Monash University Malaysia Selangor Malaysia Advanced Computing and Simulation Laboratory AXL Department of Electrical and Computer Systems Engineering Faculty of Engineering Monash University VIC Australia

Design parameters of a supervisory (SV) system intended for a distributed Raman amplifier (DBA) is investigated theoretically. The pump is low frequency modulated to transmit supervisory information which forms part of the fault management system in a Raman amplified fiber optic network. Issues regarding modulation frequency of the SV signal and its effect on the integrity of the signal are studied. Power penalty issues due to introduction of the SV signal in the optical network are also studied. These theoretical studies are based on numerical solution of coupled propagation equations for counter-pumped DRA.

关键词： Stimulated emission Distributed amplifiers Optical transmitters Repeaters Frequency Optical pumping Optical amplifiers Design engineering Distributed computing Optical propagation

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Cross-gain Modulation in TDM Pumped Raman Fiber Amplifiers

Cross-gain Modulation in TDM Pumped Raman Fiber Amplifiers

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The Joint International Conference on Optical Internet and Next Generation Network (COIN-NGNCON)

作者： Vineetha Kalavally Malin Premaratne Tin Win Department of Electrical and Computer Systems Engineering School of Engineering Monash University Malaysia Petaling Jaya Selangor Darul Ehsan Malaysia Advanced Computing and Simulation Laboratory Department of Electrical and Computer Systems Engineering Monash University Clayton VIC Australia

Signal-to-signal cross-gain modulation characteristics for a counter-pumped Raman fiber amplifier (RFA) is investigated when time division multiplexed (TDM) Gaussian pulse stream is used for pumping. Crosstalk depende... 详细信息

关键词： Time division multiplexing Stimulated emission Laser excitation Pump lasers Frequency Counting circuits Optical crosstalk Optical modulation Optical pumping Optical computing

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Aircraft maintenance technology education: Integrating asynchronous technology & virtual reality

Aircraft maintenance technology education: Integrating async...

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113th Annual ASEE Conference and Exposition, 2006

作者： Sadasivan, Sajay Vembar, Deepak Stringfellow, Paris Washburn, Carl Duchowski, Andrew Gramopadhye, Anand Cemson University Department of Industrial Engineering Clemson University SC United States Department of Computer Science Clemson University SC United States Greenville Tech United States Aircraft Maintenance Program Greenville Technical College United States Department of Computer Science Clemson University United States Industrial Engineering Department Advanced Technology Systems Laboratory Clemson University SC United States

This paper describes a research program with an objective to develop and implement an interactive virtual reality (VR) model of the aircraft inspection maintenance process for asynchronous delivery. Existing approaches have not been able to mimic accurately the complexity of the aircraft maintenance process, reporting limited transfer capabilities and student preparedness for the workplace. This use of virtual reality technology will enable educators to create and students to experience the complex aircraft maintenance environment in an educational classroom, a setting where it has not yet been successfully created using traditional multimedia-based technologies. This model will emphasize the curriculum development and workplace preparedness needed by modern aircraft maintenance technology for local, state and national audiences. The primary objectives of this research are curriculum enhancement and assessment of VR as a pedagogical tool. This innovative approach is the first effort to extend tested VR technology to the aircraft maintenance technology curriculum in a two-year college. The outcome of this research will lead to the following: an innovative, high-impact model for curriculum application in aircraft maintenance technology for college students and industry employees;an increased workplace pool of aircraft maintenance technicians prepared for the transition from learning to workforce;a program providing the use of VR technology as a pedagogical tool. The successful completion of this effort will fill a state and national need for well-prepared students entering the aircraft maintenance industry and will provide a better understanding of the use of VR as a pedagogical tool. © American Society for engineering Education, 2006.

关键词： Aircraft

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Vague Sets Based Evidence Combinational Rule With Generalized Belief Function

Vague Sets Based Evidence Combinational Rule With Generalize...

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International Conference on Information and Automation (ICIA)

作者： Lizhong Xu Zhigui Lin Simon X. Yang College of Computer and Information Engineering Hohai University HHU Nanjing China Advanced Robotics and Intelligent Systems ARIS Laboratory School of Engineering University of Guelph Guelph ONT Canada

In this paper, a new vague evidence theory is proposed to expand the conventional evidence theory. First, the concept of vague evidence theory is introduced. Based on the features of vague sets, a belief function is formulated, and its characteristics is analyzed and proved mathematically. After that, based on the degree of similarity in vague sets, the relative contribution to the combined vague sets is obtained, and a vague sets based combinational rule is formulated. Finally, experiments are conducted to demonstrate the effectiveness of the proposed vague evidence theory. The proposed vague evidence theory based method is capable of representing and processing problems with vagueness, uncertainties and imprecision.

关键词： Fuzzy sets Set theory Area measurement Measurement uncertainty Humans Intelligent robots Fuzzy set theory Educational institutions Intelligent systems Arithmetic

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Spatial Distribution of Water Quality Based on Generalized Regression Neural Network

Spatial Distribution of Water Quality Based on Generalized R...

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International Conference on Information and Automation (ICIA)

作者： Huibin Wang Lizhong Xu Shaohua Sun Simon X. Yang College of Computer and Information Engineering Hohai University HHU Nanjing China Advanced Robotics and Intelligent Systems (ARIS) Laboratory School of Engineering University of Guelph Guelph ONT Canada

The paper proposes a new model for analyzing spatial distribution of water quality. The model is based on statistics and generalized regression neural network. The model is based on statistic theories and easy to approximate a nonlinear function. The advantages of the model include simple net structure, few artificial parameters, and high accuracy calculation. The developed approach is successfully applied to the water quality assessment of the Taihu Lake of China P.R, which includes the dissolved oxygen concentration of water-quality index and the spatial distribution of the water-quality level. The results show that the model can generate a credible spatial distribution of the water quality.

关键词： Neural networks Lakes Statistical distributions Monitoring Intelligent robots Function approximation Probability density function Sun Educational institutions computer networks

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Particle Swarm Optimization based Defensive Islanding of Large Scale Power System

Particle Swarm Optimization based Defensive Islanding of Lar...

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International Joint Conference on Neural Networks (IJCNN)

作者： Wenxin Liu D.A. Cartes G.K. Venayagamoorthy Center of Advanced Power Systems (CAPS) Florida State University Tallahassee USA Real-Time Power and Intelligent Systems Laboratory the Department of Electrical and Computer Engineering University of Missouri MO USA

Defensive islanding is an efficient way to avoid catastrophic failures and wide area blackouts. Power system splitting especially for large scale power systems is a combinatorial explosion problem. Thus, it is very difficult to find an optimal solution (if one exists) for large scale power system in real time. This paper proposes to utilize the computational efficiency property of binary particle swarm optimization (BPSO) to find some efficient splitting solutions in limited timeframe. The solutions are optimized based on a cost function considering the balance between real power generation and consumption, the relative importance of customers, the capacities of distribution and transmission systems, and possibility of region to be impacted, etc. The solutions not only provide the lines to cut but also the corresponding load shedding information in each island. Simulations with large scale power system demonstrate the effectiveness of the proposed algorithm.

关键词： Particle swarm optimization Large-scale systems Power systems Power system stability Power system protection Power system dynamics Cost function Power system simulation Real time systems Power system faults

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Local Detection and Recovery from Multi-Failure Patterns in MPLS-TE Networks

Local Detection and Recovery from Multi-Failure Patterns in ...

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IEEE International Conference on Communications (ICC)

作者： Marco Tacca Kai Wu Andrea Fumagalli Jean-philippe Vasseur Optical Networking Advanced Research (OpNeAR) Laboratory Erik Jonsson School of Engineering and Computer Science University of Texas Dallas USA Cisco Systems Inc. Boxborough MA USA

MPLS Fast Reroute advocates local protection mechanisms to rapidly reroute traffic onto pre-computed and signaled bypass tunnels. When the network is subject to multiple element failures, it becomes challenging to handle all the possible failure scenarios, for they are more disruptive and may require many more bypass tunnels to be dealt with. The objective of this paper is to adapt the MPLS local recovery schemes to deal with multi-failure scenarios, while retaining as much as possible the simplicity and the fast failure detection feature of current (single failure) local recovery mechanisms. This objective is achieved by optimally grouping failure patterns into clusters and minimizing the overall additional network resources - i.e., bypass tunnels and bidirectional forwarding detection sessions - while yielding full recovery from such failure patterns.

关键词： Multiprotocol label switching Telecommunication traffic Protection Tellurium Statistics Optical fiber networks Laboratories computer science computer vision Mission critical systems

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Carrier-density evolution in polarization sensitive semiconductor optical amplifiers

Carrier-density evolution in polarization sensitive semicond...

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International Conference on Numerical Simulation of Optoelectronic Devices, (NUSOD)

作者： B. S. Gopalakrishna Pillai A. Nirmalathas C. Lim M. Premaratne ARC Special Research Centre for Ultra-Broadband Information Networks Department of Electrical and Electronic Engineering University of Melbourne VIC Australia Advanced computing and simulation laboratory Department of Electrical and Computer Systems Engineering Monash University Clayton VIC Australia

We derive analytical expressions for carrier-density evolution along a polarization-sensitive semiconductor optical amplifier (SOA) that have a range of signal processing applications. The analytical results closely m... 详细信息

关键词： Optical polarization Semiconductor optical amplifiers Tellurium Optical signal processing Optical wavelength conversion Optical sensors Optical pulses computer networks Optical computing systems engineering and theory

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