Journal of Operational Research in its Applications
Year:2012 | Volume:9 | Issue:2 (33)|Papers Count:9

Due to diversity of climates across the world and different conditions of food preservation, amounts of micro-nutrients and macro-nutrients are always subject to uncertainty. The quantity of a nutrient contained in a food can never be precisely determined and a certain value cannot be assigned to it. This uncertainty about numbers and values in medical references causes the decisions on nutrition diets based on confident data to be far from reality. The objective of the current paper is to prepare and prescribe an optimal diet in fuzzy environment. The case study was carried out on hepatitis patients owing to significance of nourishment for these individuals. Taking into account the calorific and protein-rich diet for such patients, the research problem which appears in the form of a fuzzy linear programming problem with two target functions including maximization of daily calorie and protein amounts was modeled and solved using a suitable method. Finally, through implementation of diet in fuzzy environment, acceptable results were achieved because these values are more realistic because of considering all possible states.

The present study aims at examine the relative performance of contractors is used Grey Data Envelopment Analysis model that level of tasks, and extensive input and output contractors of the projects relative to determine the input and output key is action. The raw data needed for the method of making records in 2009 MAPNA group, was collected and the Grey Data Envelopment Analysis model is to solve the model. To clarify a basic model number of contractors have been selected that include relative performance 100 percent after defining of the efficient contractors, performance of these contractors for complete ranking of performance efficient contractors was done. In the final step to provide solutions for enhancing the efficiency of inefficient contractors is available.

Eddy current testing is one of nondestructive testing (NDT). This test is used to investigate heat exchanger tubes and detecting any possible faults in these tubes. This paper aims to determine the optimum parameters of probe in order to improve sensitivity and inspection system performance. Firstly, this paper presents equations related to design and characteristics of probe to investigate sample tubes. Then, optimum design is presented in order to reach the highest signal to noise ratio (SNR) and sensitivity (S) using artificial bee colony (ABC). Finally, eddy current testing is performed for optimum probe using finite element analysis (FEA).

The operational research as a mathematical scientific method has been converted to a suitable tool in many decision making and managerial fields. Methods and models offered in the deferent branches of operational research can assist managers to recognize current situation practically and devise necessary actions for enhancement and development. This paper is an applied guide for effective and efficient evaluation of tourism attractions for tourism development policy makers, managers and planners, and a descriptive - survey research which intend to identify the most important evaluation indicators of tourism attractions according to experts’ viewpoint by the Delphi Method and then rank them using the Analytical Hierarchy Process (AHP). Unfortunately, because of inexact identification of evaluation indicators of tourism attractions and their ranking criteria, many deficiencies are now observed in evaluating and development planning of tourism attractions. Considerations completed by now, also indicate that there haven’t been done any technical and demonstrative researches in this field and just in some researches, the evaluation indicators have been collected. With respect to the mentioned facts, the authors in this paper identified the evaluation indicators of tourism attractions, their criteria and sub-criteria by the use of related Persian and English documents and writings initially and then determined final indicators, criteria and sub-criteria using the experts’ viewpoint and designed hierarchy structure. In the next stage, two questionnaire were designed, one of them was used for pair comparisons of criteria and sub-criteria and in the second, experts were requested to rank indicators from their viewpoints in accordance with these criteria and sub-criteria. Finally, the evaluation indicators of tourism attractions were prioritized according to the determined criteria utilizing the Expert Choice software.

Undoubtedly, one of the important effects of 20th century changes in Commercial and Production Environment is Globalization. In current situation, production goes above a limited and national decision and reaches universal borders up to level of strategic decision. The current research aims to comparatively evaluate the strategies of World Class Manufacturing in Steel Industries of Mazandaran Province applying a Hybrid approach taken from FAHP and FVIKOR techniques. To achieve this purpose we conducted a comprehensive review of the related researches and got help from 12 experts of Steel Industry. According to the 4 determined strategies (designing products based on customer’s needs, accepting new technology, and improving the after-sale services and identifying new markets), the findings of this research represents the high priority of “accepting new technology” strategy to achieve the World Class Manufacturing.

In many Data Envelopment Analysis (DEA) problems, Decision Making Units (DMUs) are managed under supervision of a unified system. For instance, all universities of a country are under supervision of education ministry. Thus, investments for passing from an unsuitable situation to a desirable form are done by such a system. In this situation, managers would like to know which approach is the closest to improve their system. The purpose of this paper is to present an approach in which the inefficient DMUs achieve to an efficient situation by least possible changes. For this end, in order to convert an inefficient DMU to efficient DMU, the inputs reduction of each inefficient DMU is studied. Afterwards, using an aggregating preference ranking problem, the inputs are ranked based on their closeness to the efficiency frontier. Priority of a DMU to other means that decision maker should invest on it more than other to achieve an efficient System.

In this paper, inverse DEA with performance cone constraints, when some of outputs level decision making units are undesirable, is discussed. So that, by changing the input level and maintain the efficiency index of the unit under evaluation, the desirable output level (undesirable) increase (decrease) will be. For this purpose multi objective linear programming (MOLP) model are used.

In reality, scheduling consists of assignment resources in order to perform a set of tasks in a given time horizon. Since open shop environment occurs most in real world, an appropriate and exact model presentation will be a major aid for managers and industrials. Exact data expression in scheduling problem, usually is impossible. Unforeseen events and faults in Measurment cause uncertain information. Since in operation research problems, uncertainty in data and information expression from decider lead to analysis the problem with uncertain coefficient, in this paper we consider a novel modeling for open shop scheduling with interval coefficient and parameters. The most important features for our model, are dependent removal time, setup time separated from processing time and considering inaccessibility time for machines in order to repairing, break time of workers, etc. The objective of proposed model is to minimize the total weighted tardiness. Computational results and implementing on AIMMS software present the application of model in finding optimal solution in appropriate time.