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Guchhait P.,Dherua Anchal Satabala High School | Maiti M.K.,Mahishadal Raj College | Maiti M.,Vidyasagar University
Computers and Industrial Engineering | Year: 2010

Items made of glass, ceramic, etc. are normally stored in stacks and get damaged during the storage due to the accumulated stress of heaped stock. These items are known as breakable items. Here a multi-item inventory model of breakable items is developed, where demands of the items are stock dependent, breakability rates increase linearly with stock and nonlinearly with time. Due to non-linearity and complexity of the problem, the model is solved numerically and final decisions are made using Genetic Algorithm (GA). In a particular case, model is solved analytically as well as numerically and results are compared. Models are developed with both crisp and uncertain inventory costs. For uncertain inventory costs both fuzzy and stochastic parameters are considered. A chance constrained approach is followed to deal with simultaneous presence of stochastic and fuzzy parameters. Different numerical examples are used to illustrate the problem for different cases. © 2010 Elsevier Ltd. All rights reserved. Source

Khanra A.,Bohichberia High School H.S. | Maiti M.K.,Mahishadal Raj College | Maiti M.,Vidyasagar University
Computers and Industrial Engineering | Year: 2015

Here a new model of Traveling Salesman Problem (TSP) with uncertain parameters is formulated and solved using a hybrid algorithm. For this TSP, there are some fixed number of cities and the costs and time durations for traveling from one city to another are known. Here a Traveling Salesman (TS) visits and spends some time in each city for selling the company's product. The return and expenditure at each city are dependent on the time spent by the TS at that city and these are given in functional forms of t. The total time limit for the entire tour is fixed and known. Now, the problem for the TS is to identify a tour program and also to determine the stay time at each city so that total profit out of the system is maximum. Here the model is solved by a hybrid method combining the Particle Swarm Optimization (PSO) and Ant Colony Optimization (ACO). The problem is divided into two subproblems where ACO and PSO are used successively iteratively in a generation using one's result for the other. Numerical experiments are performed to illustrate the models. Some behavioral studies of the models and convergences of the proposed hybrid algorithm with respect to iteration numbers and cost matrix sizes are presented. © 2015 Published by Elsevier Ltd. Source

Giri P.K.,Vidyasagar University | Maiti M.K.,Mahishadal Raj College | Maiti M.,Vidyasagar University
Applied Soft Computing Journal | Year: 2015

This paper presents fully fuzzy fixed charge multi-item solid transportation problems (FFFCMISTPs), in which direct costs, fixed charges, supplies, demands, conveyance capacities and transported quantities (decision variables) are fuzzy in nature. Objective is to minimize the total fuzzy cost under fuzzy decision variables. In this paper, some approaches are proposed to find the fully fuzzy transported amounts for a fuzzy solid transportation problem (FSTP). Proposed approaches are applicable for both balanced and unbalanced FFFCMISTPs. Another fuzzy fixed charge multi-item solid transportation problem (FFCMISTP) in which transported amounts (decision variables) are not fuzzy is also presented and solved by some other techniques. The models are illustrated with numerical examples and nature of the solutions is discussed. © 2014 Elsevier B.V. All rights reserved. Source

Guchhait P.,Vidyasagar University | Kumar Maiti M.,Mahishadal Raj College | Maiti M.,Vidyasagar University
Engineering Applications of Artificial Intelligence | Year: 2013

In this paper, a production inventory model, specially for a newly launched product, is developed incorporating fuzzy production rate in an imperfect production process. Produced defective units are repaired and are sold as fresh units. It is assumed that demand coefficients and lifetime of the product are also fuzzy in nature. To boost the demand, manufacturer offers a fixed price discount period at the beginning of each cycle. Demand also depends on unit selling price. As production rate and demand are fuzzy, the model is formulated using fuzzy differential equation and the corresponding inventory costs and components are calculated using fuzzy Riemann-integration. α-cut of total profit from the planning horizon is obtained. A modified Genetic Algorithm (GA) with varying population size is used to optimize the profit function. Fuzzy preference ordering (FPO) on intervals is used to compare the intervals in determining fitness of a solution. This algorithm is named as Interval Compared Genetic Algorithm (ICGA). The present model is also solved using real coded GA (RCGA) and Multi-objective GA (MOGA). Another approach of interval comparison-order relations of intervals (ORI) for maximization problems is also used with all the above heuristics to solve the model and results are compared with those are obtained using FPO on intervals. Numerical examples are used to illustrate the model as well as to compare the efficiency of different approaches for solving the model. © 2012 Elsevier Ltd. Source

Ghoshal N.,Mahishadal Raj College | Mukhopadhyay K.,Sundarban Mahavidyalaya | Roy S.K.,Jadavpur University
Liquid Crystals | Year: 2012

Monte Carlo simulation performed on a lattice system of biaxial molecules possessing D 2h symmetry and interacting with a second rank anisotropic dispersion potential yields three distinct macroscopic phases depending on the biaxiality of the constituent molecules. The phase diagram of such a system as a function of molecular biaxiality is greatly modified when a transverse dipole is considered to be associated with each molecule so that the symmetry is reduced to C 2v. Our results indicate the splitting of the Landau point, i.e. the point in the phase diagram where a direct transition from the isotropic phase to the biaxial nematic phase occurs, into a Landau line for a system of biaxial molecules with strong transverse dipoles. The width of the Landau line becomes maximum for an optimal value of the relative dipolar strength. The presence of transverse dipoles leads to the stabilization of the thermotropic biaxial nematic phase at higher temperature and for a range of values of molecular biaxiality. The structural properties in the uniaxial and biaxial phases are investigated by evaluating the first rank and second rank orientational correlation functions. The dipole-induced long-range order of the anti-ferroelectric structure in the biaxial nematic phase, is revealed. © 2012 Copyright Taylor and Francis Group, LLC. Source

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