mohammad akbari
Volume 21, Issue 3 , December 2017, , Pages 25-47
Abstract
This research aims to incorporate human factors engineering into the scheduling theory in order to exploit optimized human performance. Staff scheduling issue in which part-time employees have variable performance was studied in this paper. Objective function of the mathematical model is to minimize ...
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This research aims to incorporate human factors engineering into the scheduling theory in order to exploit optimized human performance. Staff scheduling issue in which part-time employees have variable performance was studied in this paper. Objective function of the mathematical model is to minimize staffing costs and provided model tries to determine best shifts duration and employees assignments. The unique characteristic and novelty of this study is consideration of ergonomic aspect (fatigue rate of employees) in staff scheduling problem. We used genetic algorithm to solve model. In order to examine effectiveness and efficiency of the model, a set of problems were solved. Also efficiency of GA algorithm results were compared against LINGO results. Comparison of results demonstrated that GA algorithm has good ability to find satisfying solution in reasonable computational running time. This study showed that we can model human fatigue in employee scheduling and planning and consider flexible working shifts to decrease labor cost and increase production efficiency. In order to study policies of decreasing labor fatigue and increasing his/her working capacity, applying provided model were suggested for comparing cost of policies (such as education, job rotation, automation and …) against economic benefits of them in scheduling and choosing the best.
mohammad akbari
Volume 19, Issue 4 , March 2016, , Pages 45-70
Abstract
External factors such as sanctions and the lack of cooperation from foreign suppliers, and internal factors such as lack of proper management of cash flow or inappropriate policy board, can lead to a lack of inventory. Inventory shortage is an important factor in creating the crisis in the manufacturing ...
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External factors such as sanctions and the lack of cooperation from foreign suppliers, and internal factors such as lack of proper management of cash flow or inappropriate policy board, can lead to a lack of inventory. Inventory shortage is an important factor in creating the crisis in the manufacturing processes. This article seeks to provide a system for inventory control and production. The proposed model for the production and inventory control in uncertainty modeling and it is assumed that the customer demand as well as follow a normal distribution. In this study, a mathematical model presented integer, nonlinear and is NP-hard. To solve this complex model of genetic algorithm is used. The results of the numerical model shows that a point mutation operators intersection and a good ability in the search space is justified and unjustified away from space. The convergence of the algorithm results also show that the algorithm can be used to find the optimum solution at the appropriate time.
Behrooz Dorri Nokorani; Mostafa Zandieh; Mohsen Notash
Volume 18, Issue 4 , January 2015, , Pages 183-203
Abstract
One of the organizations’ fundamental issues is supply chain network design. Optimization of this network can lead to effective management of the whole supply chain. Network design specifies the position, capacity, number and type of network facilities, and transportation network of materials and ...
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One of the organizations’ fundamental issues is supply chain network design. Optimization of this network can lead to effective management of the whole supply chain. Network design specifies the position, capacity, number and type of network facilities, and transportation network of materials and products from the supplier to the customer and vice versa. This research proposes new solution procedure based on Multi-objective Genetic Algorithm (MOGA) and Non-dominated Sorting Genetic algorithm-II (NSGAII) to find the set of Pareto optimal solutions that empowers the decision-makers by alternative solutions. Considering that in this study the level of service is very important, so this modeling was based on satisfying all customer demands. Objectives for network optimization are minimization of total cost and maximization of capacity utilization balance for network facilities that lead to the reduction of customers’ service time (increase service levels). Nine problems were designed from small to large. In order to compare the quality of the obtained Pareto solutions of both algorithms, seven criteria (for multi-objective problems) were used in this study. The results indicated that the solutions produced by NSGAII algorithm have higher quality.
hannan amoozad mahdiraji; Mohammad Moddares Yazdi; Ali Mohaghar; Ahmad Jaafarnejad
Volume 18, Issue 1 , May 2014, , Pages 171-191
Abstract
Supply chain (SC) management aims to increase the overall profit through improvement of various activities and components. Many contradictions between parts and different levels of a SC have been identified in order to achieve overall objectives. Such shortfalls may result in decreased strength and competitiveness ...
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Supply chain (SC) management aims to increase the overall profit through improvement of various activities and components. Many contradictions between parts and different levels of a SC have been identified in order to achieve overall objectives. Such shortfalls may result in decreased strength and competitiveness of the SC. The basics of game theory make it a suitable and reliable tool for solving contradiction situations by considering all levels and players goal. For Solving the problem mentioned above, game theory approach besides coordination mechanism are performed in this research. First of all an unlimited three echelon supply chain including S suppliers, M manufacturers and K retailers are considered. For this matter, a mathematical cooperative model based on specific assumptions is proposed. The model was performed in a numerical example and it is solved by genetic algorithm. The sensitivity analysis of proposed model was analyzed by design of experiment and finally the verification of the cooperative model is assessed by simulation and Arena software.
mohammad akbari; Mostafa Zandieha; Behroz Dorri
Volume 17, Issue 3 , September 2013, , Pages 1-21
Abstract
The goal of this research is providing optimization approach for bi-objective scheduling work shifts and job rotation problem in order to exploit efficient performance of employees. In this article scheduling work shifts and job rotation problems had been modeled in one mathematical model with two objective ...
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The goal of this research is providing optimization approach for bi-objective scheduling work shifts and job rotation problem in order to exploit efficient performance of employees. In this article scheduling work shifts and job rotation problems had been modeled in one mathematical model with two objective functions: minimizing labor cost and maximizing number of job rotation. Also human factors (fatigue, learning and forgetting) that have effect on workers performance were modeled. Presented model was mixed integer and nonlinear and genetic algorithm and ε-constraint technique have been used to solve it and gain Pareto sets. To illustrate efficiency of provided algorithm, its performance has been compared to results of LINGO. The results indicated that performance of genetic algorithm is better than that of LINGO in terms of computational time and objective value. To relate relationship between objectives, set of problems have been solved. Obtained Pareto indicated that there is a conflict between objectives. Hence with considering human factors that have effect on workforce’s performance it is needed to plan work shifts and job rotation simultaneously. Results indicated that the proposed optimization approach is capable to provide suitable alternatives while managers try to consider decreasing cost, increasing jobs variety and multi-skilled training.
Reza Najari; Mohammad Javad Hozoori; Ali Salehi; Hasan Danayefard
Volume 17, Issue 3 , September 2013, , Pages 23-47
Abstract
Psychological capital is a new concept that has been discussed in the third millennium and entered in the field of management since 2006 Due to its unique role in organizational wealth-generation, it has become in the core attention of scholars and intellectuals research in the field of behavior, human ...
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Psychological capital is a new concept that has been discussed in the third millennium and entered in the field of management since 2006 Due to its unique role in organizational wealth-generation, it has become in the core attention of scholars and intellectuals research in the field of behavior, human resource management and human capital. So the main goal of this paper is designing a model to improve psychological capital in Iranianpublic organizations with identifying the role of human resource functions. This research has employed quantitative approach and followed correlation method. The populations for this study were employees of public organizations; the rational for selection of them was classification system in the governmental budget. Accordingly, they were classified into the three categories of general, social and economic. On the other hand, due to the wide dispersion and large organizations across the country, public organizations of Tehran province were chosen as key clusters.
The research method is descriptive correlation study, and the data were collected using standard questionnaires. The data were analyzed by using structural equations and multiple regressions. The research findings showed that HR functions have significant positive relation with the psychological capital; however when organizational justice is placed as the intervening variable between them, the correlation coefficient is increased. The results also indicated that HRM functions have the greatest effect on Psycap by organizational justice. At last, fitness test of the model demonstrated that it is suitable for Iranian public organizations.
Reza Kazemzadeh; Roohangiz Asadi; Isa Nakhaei Kamal Abadi; Zahra Bagherinejad
Volume 17, Issue 2 , May 2013, , Pages 1-18
Abstract
In this study, we developed a Joint Replenishment Problem (JRP) model; In addition, JRP was introduced through capacitated vehicle to send the parts. The model was developed as an Integer-non linear model. Cost function consists of the major ordering cost, the minor ordering cost and the holding cost. ...
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In this study, we developed a Joint Replenishment Problem (JRP) model; In addition, JRP was introduced through capacitated vehicle to send the parts. The model was developed as an Integer-non linear model. Cost function consists of the major ordering cost, the minor ordering cost and the holding cost. Previous studies had not considered transaction cost; therefore, we considered transaction cost, which depends on the number of different parts in the order. Demand for parts was considered as constant and the model was solved by using a genetic algorithm. For calculating variable, we developed the present algorithm in the literature. We solved the model for two conditions, with dispatch volume restriction and without dispatch volume restriction. The results showed that the dispatch volume increases both the cycle time and the total cost. The model was solved for one of the major manufacturers of SAPCO. We considered the problem with 12 strategic parts of this company. The model was investigated through the real data gathered from the SAPCO Company. Finally, for model validation, the results were compared with the traditional ordering system of SAPCO, in which the parts are ordered separately. It was shown that the proposed system has better performance than the traditional ordering system. Validation of Model was performed by the numerical example that has been solved in the literature. Keywords: Joint replenishment, Automotive parts, Genetic algorithm, Inventory.
Abdul Mohammad Mahdavi
Volume 11, Issue 20 , December 2007, , Pages 235-263
Abstract
This article while describing the problem and methodology of research and also reviewing briefely its theoretical basis, explains the proposed MISSQM1 moldel based on Genetic Algorithm and its major characteristics. These characteristeristics are:
1) Assurace of choice possivitity and near to optimum ...
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This article while describing the problem and methodology of research and also reviewing briefely its theoretical basis, explains the proposed MISSQM1 moldel based on Genetic Algorithm and its major characteristics. These characteristeristics are:
1) Assurace of choice possivitity and near to optimum prioritizing of the quality measurement indexes of information systems services,
2) Providing the cooperation possibility of experts and professors in the process of defining the indexes,
3) Helping menagers to take the best or near the best decision about investing in the development of the quality of information systems services, proved by the use of analytical hierarchy process and genetic algorithm.
The scientific use of the present research in the development of theoreticel basis of information systems is discussed and some suggestions are given for future researches.
