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Optimisation of multi-channel cooperative sensing in cognitive radio networks

IET COMMUNICATIONS 2013年第12期7卷 1177-1190页

作者： Zhao, Nan Pu, Fangling Xu, Xin Chen, Nengcheng Wuhan Univ Sch Elect Informat Wuhan Luojiashan 430072 Peoples R China Wuhan Univ State Key Lab Informat Engn Surveying Mapping & R Wuhan 430079 Peoples R China

Cooperative spectrum sensing (CSS) is a promising technique in cognitive radio networks (CRNs) that utilises multi-user diversity to mitigate channel instability and noise uncertainty. In this study, the relationship between 'cooperation mechanisms' and 'spatial-spectral diversity' over multiple channels jointly sensing is investigated in the presence of an imperfect reporting channel. The multiple channels are sensed at the receiver built on the filter bank-based multi-carrier system. The multi-channel CSS strategies are modelled by the introduced 'cooperative ratio' to balance the requirements on 'sensing accuracy', 'efficiency' and 'overhead', which is quantitatively characterised by the energy consumption. The target of CSS is to maximise the aggregate opportunistic throughput of secondary users (SUs) by jointly considering constraints on sensing overhead and the aggregate interference to primary users (PUs). The optimisation is divided into two sequential sub-optimisation processes, 'multi-user diversity optimisation' and 'multi-channel diversity optimisation'. An approach is developed from generic algorithms to solve the two sub-problems. Numerical results show that the optimal CSS scheme is effective in improving channel utilisation for SUs with low interference to PUs. This study establishes a valuable cooperative model for the design of multi-channel spectrum sensing algorithms in CRNs.

关键词： cognitive radio diversity reception optimisation radio spectrum management signal detection wireless channels cooperative communication multichannel cooperative sensing cognitive radio networks cooperative spectrum sensing multiuser diversity channel instability noise uncertainty cooperation mechanisms spatial-spectral diversity imperfect reporting channel filter bank-based multicarrier system multichannel CSS strategies cooperative ratio sensing accuracy energy consumption aggregate opportunistic throughput secondary users sensing overhead aggregate interference primary users multichannel diversity optimisation generic algorithms channel utilisation cooperative model multichannel spectrum sensing algorithms

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Introspective sorting and selection revisited

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SOFTWARE-PRACTICE & EXPERIENCE 2000年第6期30卷 617-638页

作者： Valois, JD Rensselaer Polytech Inst Dept Comp Sci Troy NY 12180 USA

We describe two improvements to introspective sorting and selection algorithms: a simple rule fine-grained introspection that detects potential worst-case performance after only a small constant number of partitioning steps, and the use of remedial randomization as an intervention strategy in order to reduce the performance penalty for false positives. We present experimental results showing that these techniques provide significant improvements in the running time for worst-case and other troublesome inputs, without sacrificing performance on well-behaved inputs. Copyright (C) 2000 John Wiley & Sons, Ltd.

关键词： Quicksort Find sorting and selection algorithms introspective algorithms hybrid algorithms generic algorithms

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Computing Parameters of Sequence-Based Dynamic Graphs

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THEORY OF COMPUTING SYSTEMS 2019年第3期63卷 394-417页

作者： Casteigts, Arnaud Klasing, Ralf Neggaz, Yessin M. Peters, Joseph G. Univ Bordeaux CNRS LaBRI Talence France CNRS INSA Toulouse LAAS Toulouse France Simon Fraser Univ Sch Comp Sci Burnaby BC Canada

We present a general framework for computing parameters of dynamic networks which are modelled as a sequence G=(G1,G2,...,G) of static graphs such that Gi=(V,Ei) represents the network topology at time i and changes between consecutive static graphs are arbitrary. The framework operates at a high level, manipulating the graphs in the sequence as atomic elements with two types of operations: a composition operation and a test operation. The framework allows us to compute different parameters of dynamic graphs using a common high-level strategy by using composition and test operations that are specific to the parameter. The resulting algorithms are optimal in the sense that they use only O() composition and test operations, where is the length of the sequence. We illustrate our framework with three minimization problems, bounded realization of the footprint, temporal diameter, and round trip temporal diameter, and with T-interval connectivity which is a maximization problem. We prove that the problems are in NC by presenting polylogarithmic-time parallel versions of the algorithms. Finally, we show that the algorithms can operate online with amortized complexity (1) composition and test operations for each graph in the sequence.

关键词： Dynamic networks Property testing generic algorithms Temporal connectivity

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Small generic hardcore subsets for the discrete logarithm: Short secret DL-keys

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INFORMATION PROCESSING LETTERS 2001年第2期79卷 93-98页

作者： Schnorr, CP Univ Frankfurt Fachbereich Math Informat D-60439 Frankfurt Germany Bell Labs Murray Hill NJ 07974 USA

Let G be a group of prime order q with generator g. We study hardcore subsets H subset of G of the discrete logarithm (DL) log(g) in the model of generic algorithms. In this model we count group operations such as multiplication and division, while computations with non-group data are for free. It is known from Nechaev [Math. Notes 55 (1994) 165] and Shoup [Lecture Notes in Comp. Sci., Vol. 1233, Springer, Berlin, 1997, p. 256] that generic DL-algorithms for the entire group G must perform root 2q generic steps. We show that DL-algorithms for small subsets H subset of G require 1/2m + o(m) generic steps for almost all H of size #H = m with m less than or equal to rootq. Conversely, 1/2m + 1 generic steps are sufficient for all H subset of G of even size m. Our main result justifies to generate secret DL-keys from seeds that are only 1/2 log(2) q bits long. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： computational complexity cryptography discrete logarithm (DL) generic algorithms generic complexity hardcore subsets

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A new hybrid optimization algorithm

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COMPUTERS & INDUSTRIAL ENGINEERING 1999年第2期36卷 409-426页

作者： Shi, L Olafsson, S Chen, Q Univ Wisconsin Dept Ind Engn Madison WI 53706 USA Iowa State Univ Dept Ind & Mfg Syst Engn Ames IA 50011 USA

We develop a new optimization algorithm that combines the genetic algorithm and a recently proposed global optimization algorithm called the nested partitions method. The resulting hybrid algorithm retains the global perspective of the nested partitions method and the local search capabilities of the genetic algorithm. We also present a detailed application of the new algorithm to a NP-hard product design problem and it is found empirically to outperform a pure genetic algorithm implementation, particularly for large problems. (C) 1999 Elsevier Science Ltd. All rights reserved.

关键词： combinatorial optimization generic algorithms nested partitions method product design

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Fuzzy controller design for municipal incinerators with the aid of genetic algorithms and genetic programming techniques

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WASTE MANAGEMENT & RESEARCH 2000年第5期18卷 429-443页

作者： Chang, NB Chen, WC Natl Cheng Kung Univ Dept Environm Engn Tainan Taiwan

Mass burn waterwall incinerator has been the most widely used technology for processing the municipal solid waste (MSW) streams in many metropolitan regions since 1970. Not only the heterogeneity of physical composition and chemical property of the MSW but also the complexity of combustion mechanism would significantly influence the performance of waste incineration. As a result, a successful operation requires an advanced combustion control system for handling many uncertain factors. Conventional automatic combustion control (ACC) technology was found to be insufficient to handle such a highly nonlinear system. The successful applications of those intelligent combustion control (ICC) technologies, such as fuzzy control technology, for reducing the operational risk have received wide attention in recent years. This paper illustrates the principles, algorithms, and application potentials of the genetic fuzzy controller that is particularly designed for improving the traditional fuzzy control logic with the aid of genetic algorithms/genetic programming techniques. Practical implementation of this methodology was assessed by a simulation analysis based on three representative types of mass burn waterwall incinerators in Taiwan. It indicates that the quality of combustion control in those three municipal incinerators can be possibly enhanced via the use of genetic fuzzy control logic. The application of such a hybrid fuzzy control technology can be easily extended to many other types of industrial incinerators, such as modular, rotary kiln, and fluidized bed incinerators, by a slightly different approach.

关键词： fuzzy control generic algorithms genetic programming incinerator neural network solid waste management

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Adaptive navigation of autonomous vehicles using evolutionary algorithms

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ARTIFICIAL INTELLIGENCE IN ENGINEERING 1999年第2期13卷 159-173页

作者： Nearchou, AC Univ Patras Dept Engn Mech Patras 26500 Greece

Autonomous vehicles must be able to navigate freely in a constrained and unknown environment while performing a desired task. To increase its autonomy, a vehicle must be provided by sophisticated software navigators. Traditionally, navigators build a convenient model of the vehicle's environment and plan feasible paths by reasoning about what actions must be performed to control the vehicle in that environment. This paper presents a genetic algorithm for adaptive navigation of a robot-like simulated vehicle. The proposed algorithm evolves feasible paths by performing an adaptive search on populations of candidate actions. The performance of the algorithm is demonstrated on problems with vehicles moving in two-dimensional grids and compared with that of a simple greedy algorithm and a random search technique. (C) 1999 Elsevier Science Ltd. All rights reserved.

关键词： adaptive navigation evolutionary computation generic algorithms variable length chromosomes

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On generating optimal signal probabilities for random tests: A genetic approach

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VLSI DESIGN 1996年第3期4卷 207-215页

作者： Srinivas, M Patnaik, LM INDIAN INST SCI MICROPROCESSOR APPLICAT LABBANGALORE 560012KARNATAKAINDIA

Genetic algorithms are robust search and optimization techniques. A Genetic Algorithm based approach for determining the optimal input distributions for generating random test vectors is proposed in the paper. A cost function based on the COP testability measure for determining the efficacy of the input distributions is discussed, A brief overview of Genetic algorithms (GAs) and the specific details of our implementation are described. Experimental results based on ISCAS-85 benchmark circuits are presented. The performance pf our GA-based approach is compared with previous results. While the GA generates more efficient input distributions than the previous methods which are based on gradient descent search, the overheads of the GA in computing the input distributions are larger. To account for the relatively quick convergence of the gradient descent methods, we analyze the landscape of the COP-based cost function. We prove that the cost function is unimodal in the search space. This feature makes the cost function amenable to optimization by gradient-descent techniques as compared to random search methods such as Genetic algorithms.

关键词： testing random test vectors signal probabilities generic algorithms COP testability measure

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Restoring boundary conditions in the solidification of pure metals

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COMPUTERS & STRUCTURES 2011年第1-2期89卷 48-54页

作者： Slota, Damian Silesian Tech Univ Inst Math PL-44100 Gliwice Poland

The scope of the paper is an algorithm reconstructing the boundary conditions (heat flux and heat transfer coefficient) in the solidification of pure metals on the grounds of temperature measurements. For the verification of the algorithm experimental data derived in the course of the solidification of aluminum were used. An example of the application of the algorithm for designating the cooling conditions in continuous casting is provided, when the values of temperature at selected points on the boundary of the casting are known. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： Solidification Inverse Stefan problem generic algorithms Continuous casting

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Integration of Energy Storage for Voltage Support in Distribution Systems with PV Generation

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JOURNAL OF ELECTRICAL ENGINEERING & TECHNOLOGY 2016年第5期11卷 1077-1083页

作者： Shaaban, Mohamed Petinrin, J. . O. Port Said Univ Dept Elect Engn Fac Engn Port Fouad 42523 Port Said Egypt Fed Polytech Ede Sch Engn Elect Elect Engn Dept Ede Osun State Nigeria

The exploitation of PV generation offers substantial environmental benefits. Yet, the integration of these might be problematic due to its variable and intermittent nature. Energy storage can compensate for the deficiencies featured by variable PV systems. This paper provides a mathematical programming based approach for the strategic deployment of energy storage in the feeder circuits to achieve ubiquitous grid benefits. A genetic algorithm (GA) is used to solve the problem of appropriate size and location of the energy storage. Quasi-static time sequence analysis is carried out on diurnal basis, to correlate the coincidence of the PV resource output and demand. This will ensure accurate appraisal of storage impacts on the system hour by hour. The proposed approach is implemented on the IEEE 123 node test feeder under various penetration levels and operating scenarios. Results have consistently affirmed that the proposed approach is efficient in maintaining system's voltage profile at various conditions as well as reducing the overall thermal losses.

关键词： Distribution system Energy storage generic algorithms Photovoltaic (PV) generation Smart grid Voltage control

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