A novel heuristic algorithm for QoS-aware end-to-end service composition.
ABSTRACT Many works have been carried out to find the efficient algorithms for QoS-aware service composition in recent years. Nevertheless, on one hand, some of these works only consider the local QoS attributes in Web services composition; on the other hand, some ideas derived from QoS selection algorithms for network routing are directly applied in service composition without any adaption. A service composition model with end-to-end QoS constraints has been presented in this paper. An improved heuristics HCE based on the observation of characteristic of end-to-end service composition is proposed as a novel solution. Simulation results reveal the better performance of proposed heuristic compared to the other two heuristics, HMCOP and generic CE algorithm.
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ABSTRACT: One of the most important works in technology of web service is web service composition. In the recent years numerous studies to develop methods to build composite web services is carried out but making composite web service yet is a complex issue. In this paper a QOS-aware method based on imperialist competition algorithm for web services selection is proposed. In this method called ICA-WSS, web service selection is done based on QOS parameters. ICA-WSS takes an abstract process and a set of all candidate web services and tries to find an optimal combination based on QOS parameters. In comparison to QQDSGA without considering QOE parameters, ICA-WSS finds better combination in term of value of objective function. Experimental results endorse that ICA-WSS is an efficient algorithm with good convergence for solving problem of web service composition.
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ABSTRACT: In this paper three optimization algorithms were used in order to solve the problem of dynamic composition of Web services with Quality of Service (QoS). This combinatorial optimization problem arises when multiple services, which provide subfunctions for a complete function, are aggregated in an execution flow and presented to the user as a single service. This problem has been modeled in the context of two deterministic and one stochastic algorithms, aiming to determine the best flow in terms of QoS. Besides, a performance evaluation was executed considering the composition algorithms in some scenarios and comparing them in terms of response time and quality of the obtained solution. The stochastic algorithm proved to be more advantageous for these scenarios due the deadline exploitation on the search for an optimal solution, although it does not provide guarantees of optimality.Proceedings of the 19th Brazilian symposium on Multimedia and the web; 11/2013
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ABSTRACT: Quality of service (QoS) based provisioning for service-oriented network applications has been actively discussed because of user's specific requirements. An order relation vector model is proposed in this paper, which can be used to represent and calculate user's preference information effectively. User's preference order of QoS attributes is a possible approach to formulate user's specific QoS requirements in the context. In order to apply the preference order to actual application, a QoS attribute matrix is introduced to manage QoS attribute value; at the same time, a feasible method of defuzzifying and normalizing is also introduced to deal with the original QoS attribute matrix; user's preference order and the normalized QoS attribute matrix are used to calculate user's QoS attribute weight vector, which can be regarded as an evaluation criterion reflecting user's different QoS preference degrees. Finally, a service composition model and algorithm is proposed in this paper. The numerical examples indicate that the model delivers user's QoS preference reliably and the experiment shows that the algorithm is efficient. (C) 2013 Published by Elsevier GmbH.Optik - International Journal for Light and Electron Optics 10/2013; 124(20):4439-4444. DOI:10.1016/j.ijleo.2013.03.006 · 0.77 Impact Factor