Saeed Fathi; Majid Esmailian; Farzaneh Ghandehari; Yaghoob Shirangi; Alireza Ajam
Volume 19, Issue 3 , September 2015, , Pages 218-241
Abstract
Capital structure policy is a mean to tradeoff between risk and return and many factors influencing the optimal capital structure for each company. The aim of this study is to investigate the factors affecting the capital structure of companies listed in Tehran Stock Exchange and some selected stock ...
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Capital structure policy is a mean to tradeoff between risk and return and many factors influencing the optimal capital structure for each company. The aim of this study is to investigate the factors affecting the capital structure of companies listed in Tehran Stock Exchange and some selected stock exchanges in the developed and developing countries, and compare these determinants in a domestic versus international setting. Determinants of capital structure, considered in this research, are in the firm and country levels. In the firm level, profitability distance from bankruptcy, size and the ratio of fixed assets to total assets are used, and in the country level, the role of country’s GDP growth and stock market development is investigated. For international companies, we used Compustat Global Vantage database and World Bank databases and for domestic companies, we used Tadbirpardaz database to collect data. The findings showed the determinants significantly effecting on capital structure in four populations: the whole world, developed countries, developing countries, and Iran. Finally, we found that the developed and developing countries profitability and the size have different effects on capital structure. Alternatively in comparison between Iran and the developed countries, size and the ration of fixed assets have different effects on capital structure.
majid Esmaelian; ahmad jafarnajad
Volume 15, Issue 2 , May 2011, , Pages 47-70
Abstract
The purpose of preventive maintenance management is to perform a series of tasks that prevents or minimizes production breakdowns and improves the reliability of production facilities. The inspection, repair, and replacement of production equipment are tasks that are central to preventive maintenance ...
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The purpose of preventive maintenance management is to perform a series of tasks that prevents or minimizes production breakdowns and improves the reliability of production facilities. The inspection, repair, and replacement of production equipment are tasks that are central to preventive maintenance management.
An important objective of preventive maintenance management is to minimize the downtime of production facilities. In order to accomplish this objective, management personnel has to efficiently allocate resources and determine an effective maintenance schedule. Mathematical models have been developed to solve the preventive maintenance-scheduling problem of assigning skilled personnel to work with tasks that require a set of corresponding skills.
However, there are several limitations in the prior work in this area of research. The craft-combination problem has not been solved because the craft-combinations is assumed to be given. The craft-combination problem concerns the computation of all combinations of assigning multi-skilled workers to accomplishing a particular task. In fact, determining craft-combinations is difficult because of the exponential number of craft-combinations that are possible.
This research provides an integrated solution for the preventive maintenance-scheduling problem with multi-skilled workforce constraints.
Two novel preventive maintenance-scheduling model is formulated to automatically produce the optimal solution and craft combination.
Ahmad Jafarnejhad; Majid Esmaelian; Masood Rabieh
Volume 12, Issue 4 , January 2009, , Pages 127-153
Abstract
One of the most important permanence factors in today’s competition environment is decreasing of the cost of the products. Selecting the appropriate suppliers can significantly reduce the purchasing cost and increase organization competitiveness. It is due to the fact that in most industries, the cost ...
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One of the most important permanence factors in today’s competition environment is decreasing of the cost of the products. Selecting the appropriate suppliers can significantly reduce the purchasing cost and increase organization competitiveness. It is due to the fact that in most industries, the cost of raw material and component parts includes the main cost of a product. The aim of this paper was to introduce a fuzzy decision making approach for supplier selection problems in supply chain. Most of such decisions are unstructured and many of the performance criteria such as quality, cost, flexibility and delivery time to determine the best supplier should be considered. In this paper, verbal variables were used for evaluation and determination of the performance of supplier under each criterion and determination of the weight of the criteria. Verbal variables were described by means of the triangular and trapezoid fuzzy numbers. Furthermore, the priority and the rank of suppliers by fuzzy multi-criteria decision making were determined. Finally, an example was presented to the process of decision making.
Ahmad Jafarnejhad; Majid Esmaelian; Mehradn Rzvani
Volume 12, Issue 1 , March 2008, , Pages 105-125
Abstract
In this research We introduce a new distribution center (DC) location model that incorporates working inventory and safety stock inventory costs at the distribution centers. In addition, the model incorporates transport costs from the suppliers to the DCs that explicitly reflect economies of scale through ...
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In this research We introduce a new distribution center (DC) location model that incorporates working inventory and safety stock inventory costs at the distribution centers. In addition, the model incorporates transport costs from the suppliers to the DCs that explicitly reflect economies of scale through the use of a fixed cost term.
The model was formulated as a non-linear integer-programming problem. The algorithms were tested on the problems with 15 retailers and 5 distribution centers. We uses SOLVER of Excel for modeling, solution and sensitivity analysis of the results.
Finally, the sensitivity of the results to changes in key parameters including the fixed cost of placing orders was discussed. Significant reductions in these costs might be expected from e-commerce technologies. The model suggests that as these costs decrease, it is optimal to locate additional facilities.
Mansour Moemeni; Behroz Zarei; Majid Esmaelian
Volume 10, Issue 4 , March 2007, , Pages 211-230
Abstract
The purpose of this study is to explain the ability of the computer simulation methodology to improve productivity of a production system. At the beginning, it demonstrates how simulation can be employed in productivity analysis. In this regard, a case study approach was used and the proposal methodology ...
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The purpose of this study is to explain the ability of the computer simulation methodology to improve productivity of a production system. At the beginning, it demonstrates how simulation can be employed in productivity analysis. In this regard, a case study approach was used and the proposal methodology was implemented to represent the simulation capability to enhance the productivity in the case study.
An explanation of the existing system was presented and the corresponding model called AS-IS model was designed, then the model was runned and the output was analyzed. The results of the study showed the bottlenecks and performance measures of the existing system and the initiated two models according to the simulation output, called TO-BE models.
The results obtained from the simulation experiment showed the performance measure in the TO-BE models. The manager of the company, has selected the TO-BE2 model as the best alternative based on the economical and others measure.
Mansour Moemeni; Majid Esmaelian
Volume 10, Issue 4 , March 2007, , Pages 231-251
Abstract
The purpose of this study is to explain the ability of the simulation methodology to consider uncertainty of the multi criteria decisions making. The rank order of decision alternatives depends on two types of uncertainty:(1) uncertainty associated with the decision making judgment regarding each element ...
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The purpose of this study is to explain the ability of the simulation methodology to consider uncertainty of the multi criteria decisions making. The rank order of decision alternatives depends on two types of uncertainty:(1) uncertainty associated with the decision making judgment regarding each element of decision matrix described by distribution function, and (2) uncertainty regarding the future characteristics of the decision making environment described by a set of scenarios. Scenario is description of the decision making environment into some separate situations . Researchers concentrate on this type of uncertainty less than other types.
Both types of uncertainty are capable to opposite the rank of alternatives and decline the certainty of decision maker to the rank order of alternatives. In The present research, a simulation approach for handling both types of related uncertainty was described. The final conclusions showed that when uncertainty associated with the decision making judgment regarding each element of decision matrix increases, the probability of rank reversion and rank uncertainty increases too. Under these situations, the final ranking of the alternatives is probabilistic.
