Current Issue : October - December Volume : 2014 Issue Number : 4 Articles : 6 Articles
In this paper, 2-point block method with two off-step points based on Backward Differentiation Formula (BDF) for\nsolving stiff ODEs is formulated. The strategy of the developed method is to calculate two solution values of the\nmethod with two off-step points simultaneously at each iteration. Stability region and convergence of the method\nare also generated. The numerical results obtained are compared with the fifth order 2-point block BDF method to\ncompare the enhancement of the method in terms of accuracy....
Data envelopment analysis (DEA) is a non-parametric approach for measuring the efficiency of decision\nmaking units (DMUs) that use multiple inputs in order to produce multiple outputs. In most real\napplications, DMUs have a two-stage network process which can be used for management of organizations\nsuch as hospitals, insurance companies, banks, and etc. The data are crisp in the standard DEA model\nwhereas there are many problems in the real life that data may be uncertain. Thus, in this paper, we\npropose a model to estimate the efficiency of DMUs with a two-stage structure and the inputs and outputs\nof DMUs are fuzzy data. Also, DEA can be used to allocate resources; therefore, we propose a new\nmethod to allocate resources for DMUs with a two-stage structure and fuzzy data. The main aim of this\nallocation is preserving the efficiency score of DMUs. We illustrate the applicability of models by using a\nnumerical example....
In this paper, the chirped- free optical pulses compression through propagating in silica ââ?¬â?? index guiding\nphotonic crystal fibers will be studied. The results show that the Raman Effect can enhances the quality of\ncompressed pulses and also the positive third-order dispersion (TOD) can be considered as the main reason\nin limiting the optical pulses compression. We will show that, the combined effects of the Raman\nscattering and negative TODs can causes generating much further compressed pulses in comparison with\napplying the only Raman effect or combination of that with the positive TODs. In this paper, We also\nnumerically present a novel technique to solve the wave propagation equation, which is known as the\nconcrete algorithms of split-step fourier method and fourth order Runge-Kutta (RK4) method. This method\nhas a higher accuracy, although the computational time is longer because the number of calculation steps is\nchosen very large....
In this paper, the evaluation of customers�satisfaction is investigated by using group decision making method under\nuncertainty. Here, we have used the Zadeh�s fuzzy concept to model and measure the satisfaction. For this purpose,\nwe have firstly applied the Delphi method with fuzzy Likert scales. Then, the fuzzy ELECTRE technique was used\nin order to ordering the index and questionnaires. For determining weights of the index we have applied the Zadeh�s\nextension principle. On order to show the applicability of the proposed fuzzy approach, we have provided a case study\nwhich was applied in Isfahan Gas Company....
In this paper, a computational technique is proposed for solving a nonlinear backward stochastic\ndifferential equation involving standard Brownian motion. The method is presented via the block pulse\nfunctions in combination with the collocation method. With using this approach, the nonlinear backward\nstochastic differential is reduced to a stochastic nonlinear system of 2m equations and 2m unknowns.\nThen, the error analysis is done by some preliminaries. Finally, some numerical examples demonstrate\napplicability and accuracy of this method....
In this paper we consider t-best approximation in fuzzy normed linear spaces. We consider fuzzy cyclic contraction map T, and show that there exists a point x such that M(x,Tx, t) = M(A,B, t)....
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