INTERNATIONAL JOURNAL OF APPLIED OPERATIONAL RESEARCH
Year:2014 | Volume:4 | Issue:2|Papers Count:9

Global optimization methods play an important role to solve many real-world problems. Flower pollination algorithm (FP) is a new nature-inspired algorithm, based on the characteristics of flowering plants. In this paper, a new hybrid optimization method called hybrid flower pollination algorithm (FPPSO) is proposed. The method combines the standard flower pollination algorithm (FP) with the particle swarm optimization (PSO) algorithm to improve the searching accuracy. The FPPSO algorithm is used to solve constrained optimization problems. Experimental results showed that the accuracy of finding the best solution and convergence speed performance of the proposed algorithm is significantly better compared to those achieved by the existing algorithms.

A two server Queueing System With Single and Batch Service is considered in this paper. The arrival process is assumed to be Poisson and the service rate follows an exponential distribution. Server-I serves the customers in both single and batch service, while server-II serves the customers in batch service only.  The Laplace transform of the transient and steady state behavior of the model is considered and we obtained the expressions for the expected queue length.

Due to lack of using pesticides in production of green leaf, Iran’s produced tea is considered as of the purest and healthiest teas in the world [1]. Although, by passing one century from commencement of tea cultivation and production in Iran, tea cultivation surfaces has been developed and numbers of tea making factories has been increased, no progress has been made in improvement of quality of produced dried tea and this product is not accountable for qualitative and quantitative needs of consumers [2]. Special place of tea in Iranian consumers’ basket and direct occupation of more than 70,000 households in tea cultivation and production and its role and place in economy of Guilan & Mazandaran Province have doubled the necessity of performing researches to find solutions of tea problems and its qualitative and quantitative improvement. In this article, impact of continuous training of occupied manpower in tea industry and cultivation as of the parameters of utilization management system on quality of produced tea is studied. The method of this research is field study and survey has been applied for collection of information to respond to the research questions. Thus, in addition to perform library studies and interview with tea specialists, a questionnaire, having inserted traits in questions and research hypothesis, was prepared and distributed among the experts. In this research, mean index, standard deviation and column chart were applied as descriptive statistics to define and describe the variables and one-sided t-test was used as inferential statistics to answer the research question. After analyzing obtained data from questionnaire, research hypothesis was confirmed in confidence level of 95%. Therefore, it can be stated that in confidence level of 95%, continuous training of occupied manpower in tea industry and cultivation effects on quality of produced dried tea.

The aim of this paper is to use the concept of the metafrontier function to study the determination of efficiency differentials and Technological Gap Ratio (TGR) on wheat production in Khorasan Razavi province. In this study, we used the metafrontier function and group frontier based on the concept of Stochastic Nonparametric Envelopment of Data analysis (StoNED). The data used in this study consisted of a sample of 435 wheat farms in 2011. The data samples collected from wheat farms are divided into three sizes namely small, medium and large farms. The results of estimating group frontier production functions indicate that the mean technical efficiency (TE) for small, medium and large farms are 0.426, 0.606 and 0.365, receptively. The figures were found to be mean TE for small, medium and large farms are 0.286, 0.239 and 0.248 when evaluated based on the metafrontier production function representing that the highest mean TE is devoted to small farms, while medium farms has the lowest mean technical efficiency. The average technological gap ratios for small, medium and large farms were 0.727, 0.463 and 0.725, respectively. Therefore, the medium farms frontier has the most distant to the metafrontier, while the small and large farm frontiers have the closest.

Today, in a competitive market, service organizations and producers have a great attention to optimization and customer satisfaction in order to become competitive. Service organization must reduce the number of arrival, waiting time and service time in the queue to increase the customer satisfaction. In this paper by the aim of queuing theory we analyze the optimal amount of increment in a repair shop space and number of purchasing advanced equipment in one of the branches of Iran Khodro, automobile producer and assembler in Iran, in order to reduce customer waiting time; then we fine M/M/S, M/M/S/S, M/M/S/k models that fit to our analysis. Also we do the data sensitivity analysis in each part of the repair shop with respect to the cost of each situation and the effect of it on the whole system; then we specify the economic optimal service level in order to rearrange the stations in this branch.

Considering convergent product as an important manufacturing technology for digital products, we integrate functions and sub-functions using a comprehensive fuzzy mathematical optimization process. To form the convergent product, a web-based fuzzy network is considered in which a collection of base functions and sub-functions configure the nodes and each arc in the network is to be a link between two nodes. The aim is to find an optimal tree of functionalities in the network adding value to the product in the web environment. First, a purification process is performed in the product network to assign the links among bases and sub-functions. Then, numerical values as benefits and costs are determined for the arc and the node, respectively. Also, a fuzzy customers’ value corresponding to the arcs is considered. Next, the Steiner tree methodology is adapted to a multi-objective model of the network to find the optimal tree. A fuzzy multi-objective solution methodology is developed for solving the proposed problem. Finally, an example is worked out to illustrate the proposed approach.

This paper presents a fuzzy goal programming (FGP) methodology for solving bi-level quadratic programming (BLQP) problems. In the FGP model formulation, firstly the objectives are transformed into fuzzy goals (membership functions) by means of assigning an aspiration level to each of them, and suitable membership function is defined for each objectives, and also the membership functions for vector of fuzzy goals of the decision variables controlled by decision maker at the first level are developed in the model formulation of the problem. To achieve the highest membership value of each of the fuzzy goals, we formulate the problem by minimizing the negative deviational variables and thereby obtaining the most satisfactory solution for all decision makers. A numerical example is given to demonstrate the proposed approach.

The productivity change of a decision making unit (DMU) between two time periods can be evaluated by the Malmquist productivity index. In this study, we propose a method to compute the Malmquist productivity index in several time periods (from the first to the last periods) on interval data in data envelopment analysis (DEA). Then, the obtained Malmquist productivity index is compared with Malmquist productivity index between two time periods (the first and last time periods) on interval data. The aim of this paper is to investigate the progress and regress of decision making units (DMUs) in several time periods by considering all time periods between the first and the last one, on interval data. Consequently when the Malmquist productivity index is computed in several time periods, progress and regress of decision making units can be evaluated more carefully than before. What is more, one can judge with greater accuracy whether or not such strategy are favorable and promising. Lastly, a numerical demonstration illustrates the procedure of the proposed method; then some conclusions are reached, and directions for future research are suggested.

The concept of Value Creation is gaining momentum in Iran under the open regime. Iranian Companies are geared to understand and act upon the concept of Shareholder Value to stay competitive in this unfathomable and volatile environment. Most executives today understand that, the need to create shareholder value is paramount and the world’s most competitive management teams are responding to the pressure to create value by embracing new metrics and new models for managing their companies. This paper examined the content of information Equity Market Value for explaining Cash Flow Return on Investment (CFROI) and Created Shareholder Value (CSV) in Iran Companies by Alfred Rappaport model, a refined model based on Market Values, believed to be a superior model when compared to the traditional Metrics (ROE, ROA, ROS, EPS, CFO) and various models developed by Consulting Firms (EVA, MVA, REVA, AEVA, SVA, CVA, CFROI, CSV) to analyze Value Creation. For this purpose a sample of 21 companies representing in the automotive of industry for a period of five years from 2006-2012 have been analyzed. The Research results indicate that there is significant relationship and positive between CFROI and Equity Market Value, while there is not relationship between CSV and Equity Market Value.