Journal Sciences News
Membrane Technology
December 2013
Editorial Board
Publication date: December 2013
Source:Mathematical and Computer Modelling, Volume 58, Issues 11–12

December 2013
Valedictory Editorial
Publication date: December 2013
Source:Mathematical and Computer Modelling, Volume 58, Issues 11–12 Author(s): Philip Broadbridge
December 2013
A fuzzy logic based decision support system for evaluation of suppliers in supply chain management practices
Publication date: December 2013
Source:Mathematical and Computer Modelling, Volume 58, Issues 11–12 Author(s): Darshan Kumar, Jagdev Singh, Om Pal Singh, Seema Supply chain management is an increasingly important organizational concern, and proper evaluation of suppliers constitutes one essential element of supply chain success. Continuous evaluation of a particular supplier becomes more important considering the fact that in most industries the cost of raw materials and component parts constitutes the main cost of a product, such that in some cases it can account for up to 70%. However, there is little research that has helped the organizations in continuous evaluation of their suppliers. We propose a new model, based on fuzzy logic to handle the various attributes, associated with supplier evaluation problems. Four multi-input single output (MISO) mamdani fuzzy inference systems have been proposed for supplier evaluation. The proposed model has also been illustrated through a case study.
December 2013
Numerical solution of a nonlinear singular Volterra integral system by the Newton product integration method
Publication date: December 2013
Source:Mathematical and Computer Modelling, Volume 58, Issues 11–12 Author(s): B. Babayar-Razlighi, B. Soltanalizadeh In this paper, we consider a nonlinear system of Volterra integral equations, and apply Newton’s method to linearize it. We solve each step of Newton’s system by the product integration technique. Also, we provide the sufficient conditions for convergence of the numerical method. Finally, we give a test problem to illustrate the applicability and accuracy of the presented method.
December 2013
HAM and DQM solutions for slip flow over a flat plate in the presence of constant heat flux
Publication date: December 2013
Source:Mathematical and Computer Modelling, Volume 58, Issues 11–12 Author(s): M.A. Moghimi, H. Tabaei, A. Kimiaeifar In this paper, an analytical solution for boundary layer flow over a flat plate with slip flow and constant heat flux surface condition has been presented for the first time. The Navier–Stokes and energy equations are reduced by a similarity transform in order for a set of nonlinear ordinary differential equations to be formed. Then, governing equations will be solved analytically by using a kind of analytic technique for nonlinear problems which has been named the homotopy analysis method (HAM). The obtained results of this study have been compared with the results of differential quadrature method (DQM) as a promising numerical method. Very good agreement has been shown between analytical results and those obtained by DQ. Finally, effects of the Prandtl number and rarefaction parameter $K$ on velocity and temperature profiles are investigated.
December 2013
Analytical mathematical feedback guidance scheme for low-thrust orbital plane change maneuvers
Publication date: December 2013
Source:Mathematical and Computer Modelling, Volume 58, Issues 11–12 Author(s): I. Shafieenejad, A.B. Novinzade, R. Shisheie This paper which is based on neighboring optimal control investigates the application of an analytical feedback guidance scheme for the problems of low-thrust orbital transfer. Neighboring optimal control is one of the methods that has been proposed for the closed-loop optimal guidance. This method focuses on expanding the cost function to second order and examining the robustness of the system by the feedback law gains. At first, the open-loop analytical guidance policy is considered as the optimal thrust steering program that will transfer the vehicle from the inclined low earth orbits to the high earth orbits. Secondly, proper feedback optimal guidance laws are analytically obtained to maintain the trajectories around their optimum with assessed disturbances. The proposed guidance scheme is distinguished for two desired performance indices as minimum-time and minimum-effort. Finally performance indices are compared and the best policy is obtained regarding the robustness of the two performance indices against disturbances.
December 2013
A multiresolution and smooth fictitious domain method for one-dimensional elliptical and Stefan problems
Publication date: December 2013
Source:Mathematical and Computer Modelling, Volume 58, Issues 11–12 Author(s): Ping Yin, Jacques Liandrat, Wanqiang Shen, Zhe Chen We present a wavelet based multiresolution method coupled with smooth fictitious domain and wavelet–vaguelette method to solve the one-dimensional elliptic problem equipped with Dirichlet boundary condition. Its advantages over the classical fictitious domain method are analyzed by interior error estimate and numerical examples. The efficiency of our method is pointed out by considering a Stefan problem with exact solution in one dimension.
December 2013
Multi-dimensional complex-valued Gabor wavelet networks
Publication date: December 2013
Source:Mathematical and Computer Modelling, Volume 58, Issues 11–12 Author(s): K.L. Mak, P. Peng, K.F.C. Yiu, L.K. Li This paper proposes a new complex-valued wavelet network based on Gabor transfer functions which have complex-valued weights, input/output variables and translation parameters. A learning algorithm is developed by using the technique of genetic algorithm to facilitate implementation of the network. The effectiveness of the proposed network is evaluated by applying the network to approximate several complicated nonlinear functions, and to tackle the 4-QAM (quadrature amplitude modulation) digital communications channel equalization and the image enhancement via feature extraction problems in signal processing. Indeed, the evaluation results obtained by testing the proposed wavelet network with real facial and textile fabric images clearly show that it is a very useful tool for solving problems in the field of complex-valued signal analysis.
December 2013
Applications of Opial inequalities on time scales on dynamic equations with damping terms
Publication date: December 2013
Source:Mathematical and Computer Modelling, Volume 58, Issues 11–12 Author(s): S.H. Saker In this paper, we will employ some dynamic inequalities of Opial’s type on time scales to prove several results related to the spacing between consecutive zeros of a solution of a second order dynamic equation with a damping term. We also obtain several results related to the spacing between a zero of the solution and/or a zero of its derivative. As a special case, we will establish some new results for differential and difference equations with damping terms. For illustration, we will derive some well-known results obtained for differential equations without damping terms. The results yield conditions for disfocality and disconjugacy for dynamic equations with damping terms on time scales.
December 2013
Airline network design and adjustment in response to fluctuation in jet fuel prices
Publication date: December 2013
Source:Mathematical and Computer Modelling, Volume 58, Issues 11–12 Author(s): Chaug-Ing Hsu, Wei-Yin Eie This study develops a series of models to determine aircraft types and flight frequencies on individual routes, and evaluate the reliability of proposed network planning during fluctuations in jet fuel prices. The reliability of individual routes is evaluated as to whether revenues from flights with initially proposed flight frequencies and aircraft types can accommodate variations in jet fuel expenditures. We define reliability as the probability that the proposed flight frequencies will operate in at least a break-even condition under future fuel price fluctuations. A case study is provided using an international airline in Taiwan to evaluate its network reliability in response to jet fuel price fluctuations in 2008. The results indicate that not only do routes with low load factors show low reliability, but long distance routes with high load factors also show low reliability during periods with high fuel prices. The results of the study provide effective ways to enhance commercial airline network designs in response to the uncertainty of jet fuel prices.
December 2013
A bi-objective stochastic optimization model for reliable warehouse network redesign
Publication date: December 2013
Source:Mathematical and Computer Modelling, Volume 58, Issues 11–12 Author(s): Jafar Razmi, AmirHossien Zahedi-Anaraki, MohammadSaleh Zakerinia This paper proposes a developed bi-objective two-stage stochastic mixed-integer linear programming model for redesigning a reliable warehouse network. In this model, the warehouses capacity which should be phased out, remained, or relocated to other warehouses, and the shipment quantity of the product between the network nodes with a consideration for two delivery lead times is to be determined. Unlike most previous works, considering two delivery lead times, the maximum capacity for each warehouse location, reliability and uncertainty are taken into account in this study. The proposed bi-objective model includes: (1) minimizing average costs including the sum of fixed, production, transportation, relocation and capacity extension costs; (2) maximizing the coverage percentage of customer demand delivered within the preferred delivery lead time. In order to obtain Pareto optimal solutions, a novel version of