In this paper we introduce two adaptive power control algorithms for downlink of underwater wireless optical cellular networks. The first approach is based on the angle of user's position with respect to optical b...
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ISBN:
(纸本)9781467377263
In this paper we introduce two adaptive power control algorithms for downlink of underwater wireless optical cellular networks. The first approach is based on the angle of user's position with respect to optical base transceiver station (OBTS) of the cell. The second scheme works according to the link distance between the user and the OBTS. Defining an optimization problem, we aim to guaranty the quality of service for each user while minimizing the transmitting power. In our methods, we utilize limited feedback channel state information (CSI) so that the algorithm could be implemented with low complexity. The simulation results for different water types demonstrate that our proposed algorithms outperform the non-adaptive scheme.
This book is the result of a successful special session on constraint-handling techniques used in evolutionary algorithms within the Congress on Evolutionary Computation (CEC) in 2007, with the aim of putting together...
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ISBN:
(数字)9783642006197
ISBN:
(纸本)9783642006180
This book is the result of a successful special session on constraint-handling techniques used in evolutionary algorithms within the Congress on Evolutionary Computation (CEC) in 2007, with the aim of putting together recent studies on constrained numerical optimization using evolutionary algorithms and other bio-inspired approaches. The book covers six main topics: The first two chapters refer to swarm- intelligence-based approaches. Differential evolution, a very competitive evolutionary algorithm for constrained optimization, is studied in the next three chapters. Two different constraint-handling techniques for evolutionary multiobjective optimization are presented in the two subsequent chapters. Two hybrid approaches, one with a combination of two nature-inspired heuristics and the other with the mix of a genetic algorithm and a local search operator, are detailed in the next two chapters. Finally, a constraint-handling technique designed for a real-world problem and a survey on artificial immune system in constrained optimization are the subjects of the final two chapters. The intended audience for this book comprises graduate students, practitioners and researchers interested on alternative techniques to solve numerical optimization problems in presence of constraints.
Mobile micro-clouds (MMCs), which are small cloud-like infrastructures that can host services for mobile users, provide a promising approach to deliver data and computation to users in low bandwidth/high latency netwo...
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ISBN:
(纸本)9781509000739
Mobile micro-clouds (MMCs), which are small cloud-like infrastructures that can host services for mobile users, provide a promising approach to deliver data and computation to users in low bandwidth/high latency networks. In this work, we take a step towards security-aware service migration for multiple servers for MMC in tactical environments. As a fundamental model, we consider two users sharing a cluster of MMCs and moving between coverage areas of different MMCs according to random walk. We formulate the problem using a finite horizon Markov Decision Process (MDP). Due to the coupling between users due to security (and possibly interference) costs, we observe that the problem is significantly more complex compared with the non-security-aware single user service migration problem studied in the literature, even in the simplest case of two users. Accordingly, we consider efficient control algorithms which aim to minimize time average costs. Particularly, we propose a modified myopic policy which aims to reduce time average costs by steering operation towards settings which would reduce the likelihood of future security cost increases, by proactively keeping the services distant. Our numerical results demonstrate that our modified myopic policy outperforms other policies in terms of average cost for various settings.
Internet Congestion Control provides a description of some of the most important topics in the area of congestion control in computer networks, with special emphasis on the analytical modeling of congestion control al...
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ISBN:
(数字)9780128036006;0128036001
ISBN:
(纸本)9780128035832
Internet Congestion Control provides a description of some of the most important topics in the area of congestion control in computer networks, with special emphasis on the analytical modeling of congestion control algorithms. The field of congestion control has seen many notable advances in recent years and the purpose of this book, which is targeted towards the advanced and intermediate reader, is to inform about the most important developments in this area. The book should enable the reader to gain a good understanding of the application of congestion control theory to a number of application domains such as Data Center Networks, Video Streaming, High Speed Links and Broadband Wireless Networks. When seen through the lens of analytical modeling, there are a number of common threads that run through the design and analysis of congestion control protocols in all these different areas, which are emphasized in this book. The book also cuts a path through the profusion of algorithms in the literature, and puts the topic on a systematic and logical footing. Internet Congestion Control provides practicing network engineers and researchers with a comprehensive and accessible coverage of analytical models of congestion control algorithms, and gives readers everything needed to understand the latest developments and research in this area.
We have developed a transfer matrix algorithm for the enumeration of compact self-avoiding walks on rectangular strips of the square lattice. The algorithm is easily adapted to other shapes or generalized to problems ...
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We have developed a transfer matrix algorithm for the enumeration of compact self-avoiding walks on rectangular strips of the square lattice. The algorithm is easily adapted to other shapes or generalized to problems such as interacting walks. These models are relevant in the study of globular proteins. (C) 2001 Elsevier Science B.V. All rights reserved.
The coordination of the attitude among different spacecraft belonging to a multiple platform system (formation or constellation) is a basic requirement in several missions, mainly the ones involving sensors like radar...
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ISBN:
(纸本)9781479953806
The coordination of the attitude among different spacecraft belonging to a multiple platform system (formation or constellation) is a basic requirement in several missions, mainly the ones involving sensors like radars or optical interferometers. It is also an open topic in research, above all as it matches the characteristics of the current trend towards interoperability and federated systems. Different approaches are possible to define and chase such a coordinated attitude. The classic control strategy is the so-called leader-follower architecture, where all spacecraft depend on ("follow") the behavior of a single master. Alternatively, the behavioral approach involves a continuous re-selection of the desired target configuration which is computed on the basis of the behavior of all the platforms. A third possibility is to define a "virtual" architecture, especially suitable with respect to the mission requirements, which is not dependent on the current kinematic state of the platforms. The paper proposes a unified treatment of these concepts by using some fundamental definitions of the consensus dynamics and cooperative control. The convergence to the targeted configuration is addressed both analytically, by using Lyapunov stability criteria, and numerically, by means of numerical simulations. The attitude requirements and constraints are highlighted and a solution for the control algorithm - involving continuous actuators on each platform is developed. A comparative analysis of different optimal control strategies, the Linear Quadratic Regulation (LQR) and the State Dependent Riccati Equation (SDRE) - suitably modified to address the needs of coordination - is presented. The results show the general value of the proposed approach with respect to either linear or nonlinear models of the dynamics.
This paper presents an adaptive wind power selling strategy to increase the income for grid-connected wind power plant attached with a battery energy storage system (BESS). The proposed selling strategy is primarily b...
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ISBN:
(纸本)9781479977871
This paper presents an adaptive wind power selling strategy to increase the income for grid-connected wind power plant attached with a battery energy storage system (BESS). The proposed selling strategy is primarily based on time varying price thresholds that are varied by our proposed adaptive algorithm. Since electricity market prices and wind power vary throughout the day, the idea is to store energy during low price-periods and sell it when prices are high. The wind farm operator could take advantage of the price variability in order to generate an extra income by choosing the best price thresholds in an adaptive manner. Twofold benefits of the proposed strategy lie in efficient energy selling along with the constraint-based efficient operation of BESS. The strategy has been analyzed for a variety of BESSs with a wide range of its energy and power capacities, and income improvement over a trivial strategy is calculated. Simulation results depict the effectiveness of the proposed strategy validated with real-world wind farm data and electricity market prices.
This paper presents an algorithm for autonomously calculating active sensing strategies applied to range sensing. The receding-horizon algorithm we use, called Ergodic Exploration of Distributed Information (EEDI), in...
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ISBN:
(纸本)9781467381833
This paper presents an algorithm for autonomously calculating active sensing strategies applied to range sensing. The receding-horizon algorithm we use, called Ergodic Exploration of Distributed Information (EEDI), involves two major components: a) calculation of an expected information density map over the search space based on prior information and a model of the sensor, and b) ergodic trajectory optimization over the sensor configuration space with respect to that information map. The ergodic control algorithm does not rely on discretization of the search or action spaces, and is well-posed for coverage with respect to the expected information density whether the information is diffuse or localized. We simulate successful localization and discrimination of targets in a two-dimensional workspace using a fixed-location range sensor under various noise levels, and compare performance to an information maximizing strategy.
Robot-aided treadmill training is an innovative rehabilitation method for patients with locomotor dysfunctions. However, in the current rehabilitation system the treadmill speed is restricted to a constant value or ad...
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ISBN:
(纸本)9781479957361
Robot-aided treadmill training is an innovative rehabilitation method for patients with locomotor dysfunctions. However, in the current rehabilitation system the treadmill speed is restricted to a constant value or adjusted by the therapist, whereas self-determined phases of accelerations and decelerations cannot be performed by the patient in an interactive and intuitive way. In order to cope with the above problems, a speed adaptive control algorithm for lower extremity rehabilitation robot system is proposed and studied. According to the characteristics that the patient's hip joint is fixed on the robot system while walking, A pull pressure sensor is used to detect a patient's movement trend and a nonlinear gain function is used to automatically set velocity transformation quantity in the treadmill speed controller. According to this principle, a set of force measuring device is designed and its feasibility is also verified by the physical prototype. The experimental results show that the proposed control algorithm is feasible and meets the requirement of the treadmill speed adaptation for Lower Extremity Rehabilitation Robot system.
This project is concerned with non-convectional direct stator winding slot cooling using water. The aim is to find optimal algorithm for control of water cooling. The control algorithms are tested on the experimental ...
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ISBN:
(纸本)9781424411832
This project is concerned with non-convectional direct stator winding slot cooling using water. The aim is to find optimal algorithm for control of water cooling. The control algorithms are tested on the experimental device, which is part of real synchronous machine with permanent magnets. The thermal model was built as a base for pump control algorithm model of a machine without thermal sensors. The Thermal model is possible used as predictor of machine heating in real time. This type of water cooling shows better effect on the machine heating than common water cooling system on the cover.
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