91 research outputs found

    PSO Algorithm Based Resource Allocation for OFDM Cognitive Radio

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    With the development of remote correspondences, the issue of data transmission lack has turned out to be more conspicuous. Then again, to sense the presence of authorized clients, range detecting procedures are utilized. Vitality recognition, Matched channel identification and Cyclo-stationary component location are the three ordinary techniques utilized for range detecting. However there are a few downsides of these strategies. The execution of vitality indicator is helpless to instability in noise power. Coordinated channel range detecting strategies require a devoted collector for each essential client. Cyclo-stationary element Detection requires parcel of calculation exertion and long perception time. This proposition talks about the routine vitality location strategy and proposed enhanced vitality identification technique utilizing cubing operation. Additionally, cyclic prefix based range detecting is talked about in this theory. Scientific Description of vitality location and cyclic prefix based range detecting strategies is likewise delineated for fading channels

    Mutation-based artificial fish swarm algorithm for bound constrained global optimization

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    The herein presented mutation-based artificial fish swarm (AFS) algorithm includes mutation operators to prevent the algorithm to falling into local solutions, diversifying the search, and to accelerate convergence to the global optima. Three mutation strategies are introduced into the AFS algorithm to define the trial points that emerge from random, leaping and searching behaviors. Computational results show that the new algorithm outperforms other well-known global stochastic solution methods.Fundação para a Ciência e a Tecnologia (FCT

    A simplified binary artificial fish swarm algorithm for uncapacitated facility location problems

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    Uncapacitated facility location problem (UFLP) is a combinatorial optimization problem, which has many applications. The artificial fish swarm algorithm has recently emerged in continuous optimization problem. In this paper, we present a simplified binary version of the artificial fish swarm algorithm (S-bAFSA) for solving the UFLP. In S-bAFSA, trial points are created by using crossover and mutation. In order to improve the quality of the solutions, a cyclic reinitialization of the population is carried out. To enhance the accuracy of the solution, a local search is applied on a predefined number of points. The presented algorithm is tested on a set of benchmark uncapacitated facility location problems.Fundação para a Ciência e a Tecnologia (FCT

    Embedding a competitive ranking method in the artificial fish swarm algorithm for global optimization

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    Nonlinear programming problems are known to be difficult to solve, especially those that involve a multimodal objective function and/or non-convex and at the same time disjointed solution space. Heuristic methods that do not require derivative calculations have been used to solve this type of constrained problems. The most used constraint-handling technique has been the penalty method. This method converts the constrained optimization problem to a sequence of unconstrained problems by adding, to the objective function, terms that penalize constraint violation. The selection of the appropriate penalty parameter value is the main difficulty with this type of method. To address this issue, we use a global competitive ranking method. This method is embedded in a stochastic population based technique known as the artificial fish swarm (AFS) algorithm. The AFS search for better points is mainly based on four simulated movements: chasing, swarming, searching, and random. For each point, the movement that gives the best position is chosen. To assess the quality of each point in the population, the competitive ranking method is used to rank the points with respect to objective function and constraint violation independently. When points have equal constraint violations then the objective function values are used to define their relative fitness. The AFS algorithm also relies on a very simple and random local search to refine the search towards the global optimal solution in the solution space. A benchmarking set of global problems is used to assess this AFS algorithm performance

    Fish swarm intelligent algorithm for bound constrained global optimization

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    The algorithm herein presented is a modified version of the artificial fish swarm algorithm for global optimization. The new ideas are focused on a set of movements, closely related to the random, the searching and the leaping fish behaviors. An extension to bound constrained problems is also presented. To assess the performance of the new fish swarm intelligent algorithm, a set of seven benchmark problems is used. A sensitivity analysis concerning some of the user defined parameters is presented

    Efficient DS-UWB MUD Algorithm Using Code Mapping and RVM

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    A hybrid multiuser detection (MUD) using code mapping and a wrong code recognition based on relevance vector machine (RVM) for direct sequence ultra wide band (DS-UWB) system is developed to cope with the multiple access interference (MAI) and the computational efficiency. A new MAI suppression mechanism is studied in the following steps: firstly, code mapping, an optimal decision function, is constructed and the output candidate code of the matched filter is mapped to a feature space by the function. In the feature space, simulation results show that the error codes caused by MAI and the single user mapped codes can be classified by a threshold which is related to SNR of the receiver. Then, on the base of code mapping, use RVM to distinguish the wrong codes from the right ones and finally correct them. Compared with the traditional MUD approaches, the proposed method can considerably improve the bit error ratio (BER) performance due to its special MAI suppression mechanism. Simulation results also show that the proposed method can approximately achieve the BER performance of optimal multiuser detection (OMD) and the computational complexity approximately equals the matched filter. Moreover, the proposed method is less sensitive to the number of users

    Dynamic Resource Allocation Algorithms for Cognitive Radio Systems

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    Cognitive Radio (CR) is a novel concept for improving the utilization of the radio spectrum. This promises the efficient use of scarce radio resources. Orthogonal Frequency Division Multiplexing (OFDM) is a reliable transmission scheme for Cognitive Radio Systems which provides flexibility in allocating the radio resources in dynamic environment. It also assures no mutual interference among the CR radio channels which are just adjacent to each other. Allocation of radio resources dynamically is a major challenge in cognitive radio systems. In this project, various algorithms for resource allocation in OFDM based CR systems have been studied. The algorithms attempt to maximize the total throughput of the CR system (secondary users) subject to the total power constraint of the CR system and tolerable interference from and to the licensed band (primary users). We have implemented two algorithms Particle Swarm Algorithm(PSO) and Genetic Algorithm(GA) and compared their results

    On a smoothed penalty-based algorithm for global optimization

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    This paper presents a coercive smoothed penalty framework for nonsmooth and nonconvex constrained global optimization problems. The properties of the smoothed penalty function are derived. Convergence to an ε -global minimizer is proved. At each iteration k, the framework requires the ε(k) -global minimizer of a subproblem, where ε(k)→ε . We show that the subproblem may be solved by well-known stochastic metaheuristics, as well as by the artificial fish swarm (AFS) algorithm. In the limit, the AFS algorithm convergence to an ε(k) -global minimum of the real-valued smoothed penalty function is guaranteed with probability one, using the limiting behavior of Markov chains. In this context, we show that the transition probability of the Markov chain produced by the AFS algorithm, when generating a population where the best fitness is in the ε(k)-neighborhood of the global minimum, is one when this property holds in the current population, and is strictly bounded from zero when the property does not hold. Preliminary numerical experiments show that the presented penalty algorithm based on the coercive smoothed penalty gives very competitive results when compared with other penalty-based methods.The authors would like to thank two anonymous referees for their valuable comments and suggestions to improve the paper. This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT - Fundac¸ao para a Ci ˜ encia e Tecnologia within the projects UID/CEC/00319/2013 and ˆ UID/MAT/00013/2013.info:eu-repo/semantics/publishedVersio

    ACO Based Routing in Internet of Things

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    The internet of things (IOT) which are belongs to the internet and interconnected all things and connected all with remotely. It is important technology and ambiguous term. It has unique identifier and collects data from network to network without interaction of human beings. Many techniques are used in IOT which collect data without any loss. But the technique ACO which gives better results than other techniques. This paper research on internet of things in which from source to the destination are cover many route but ant colony optimization (ACO) technique which gives shortest path between transmitter and receiver then optimize the route
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