stochastic/Probabilistic/fuzzy/dynamic modeling
Arezoo Khazaei; Parvaneh Samouei
Abstract
Purpose: The newsboy problem is one of the most widely used and important models in the field of inventory control. In fact, there are many industries whose products fall into the category of newosboy problem, such as seasonal goods, food products. But in practice there are more restrictions than the ...
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Purpose: The newsboy problem is one of the most widely used and important models in the field of inventory control. In fact, there are many industries whose products fall into the category of newosboy problem, such as seasonal goods, food products. But in practice there are more restrictions than the assumptions of the newsboy problem. In this article has tried, in order to make the problem more in line with the real world some limitations during production, such as outsourcing mode, capacity limit and returned goods, have been added to the problem.Methodology: This research is based on library studies and the development of mathematical modeling.Findings: In the newsboy problem, there are important parameters such as outsourcing, capacity constraints and product referral which in this study, the effect of each of these parameters on profitability has been evaluated.Originality/Value: Development of the newsboy problem in terms of outsourcing and returned products and capacity constraints.
Maryam Shoaee; Parvaneh Samouei
Abstract
Purpose: Warehousing is very important in the economies of countries, because a significant percentage of assets are stored in the warehouse. Proper warehouse design and layout has a great role in reducing costs, reducing lead time and delivery time, improving resource utilization and customer service. ...
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Purpose: Warehousing is very important in the economies of countries, because a significant percentage of assets are stored in the warehouse. Proper warehouse design and layout has a great role in reducing costs, reducing lead time and delivery time, improving resource utilization and customer service. One type of warehouse that has become widely used recently is cross dock warehouses, which differ from traditional warehouses in terms of the number of products stored and their storage time. The main purpose of this research is modeling and solving a problem that is compatible with real world conditions that have received less attention from researchers.Methodology: Multi-Objective Gray Wolf Optimization (MOGWO) algorithm is used to solve the problem and Parameters are adjusted using the Taguchi method.Findings: Using the mean ideal distance, spacing, number of pareto solutions and diversification metric, the best possible level for the algorithm parameters is determined by the signal-to-noise ratio diagram. By solving 10 examples in different sizes and reviewing the results and their solution time, it has been determined that with increasing the size of the problem, the solution time also increases.Originality/Value: In this study, in addition to considering the distance traveled in the warehouse, which most studies have done in the field of warehouse design, more use of available space in the warehouse and the satisfaction of retailers has also been considered. For this purpose, a mixed integer programing model is proposed to design a cross dock warehouse to minimize distances, minimize the vacant space of the warehouse, and maximize retailer’s satisfaction.
stochastic/Probabilistic/fuzzy/dynamic modeling
Ahmad Faridanifar; Parvaneh Samouei
Abstract
Purpose: One of the topics for manufacturers today is to discuss the diversity of customer tastes, which to manage this situation with the least change in products, requires multiple lines that have the necessary flexibility to produce these products. On the other hand, many products require assembly ...
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Purpose: One of the topics for manufacturers today is to discuss the diversity of customer tastes, which to manage this situation with the least change in products, requires multiple lines that have the necessary flexibility to produce these products. On the other hand, many products require assembly operations. The main purpose of this article is to balance these issues according to the conditions of the workforce and different products.Methodology: This paper presents two mathematical models to minimize the number of workstations per given cycle time. In the first model, all parameters are definite. Since customer demand may not be constant and this factor can affect the cycle time, the second model uses a robust approach to this issue.Findings: Analysis of various issues shows that a robust modeling approach provides a more reliable design and allows decision makers to have better assembly based on a better understanding of short-term and long-term conditions under conditions of demand uncertainty.Originality/Value: In this paper, two new mathematical models for assembly line balance are presented. Multi-models in which assembly operations are performed manually by workers and for more accurate planning, the differences that workers have in terms of learning and forgetfulness effect on assembly line balance are considered.
supply chain management analyzing/modelling
Samira Kiani; Parvaneh Samouei
Abstract
In this paper, a closed-loop supply chain for pharmaceutical items consists of a pharmacy, a distribution center, a recycling center and several pharmacy sites is considered in which two types of routing are performed. The first involves the routing of vehicles between the distribution center and the ...
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In this paper, a closed-loop supply chain for pharmaceutical items consists of a pharmacy, a distribution center, a recycling center and several pharmacy sites is considered in which two types of routing are performed. The first involves the routing of vehicles between the distribution center and the pharmacies, and the second involves the routing of vehicles to the recycling center and all nodes. Two types of pharmaceutical items are considered for this purpose, and their demand varies for different periods. The distribution center can offer discounts depending on the pharmacy orders. In addition, the distribution center can increase its capacity by renting more warehouses. Also, we have two objective functions: minimizing costs and environmental pollutants caused by carbon dioxide emissions. This problem is solved in the small-sized problem by the Epsilon constraint method and in the large cases by two hybrid algorithms based on the Fordyce-Webster algorithms and NSGAII-FW and MOSA and evaluated by different criteria. The computational results show that the NSGAII-FW algorithm is more efficient than the MOSA algorithm.