Ahmad Ebrahimi; laya olfat; Maghsood Amiri; Mohammad Taghi Taghavifard
Abstract
The current research has considered the design of the four-level supply chain of perishable goods, including manufacturing factories, distribution centers, wholesalers, and retailers, in conditions of uncertainty in important parameters. The aim is to make strategic and tactical decisions, including ...
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The current research has considered the design of the four-level supply chain of perishable goods, including manufacturing factories, distribution centers, wholesalers, and retailers, in conditions of uncertainty in important parameters. The aim is to make strategic and tactical decisions, including the location, number, and size of distribution centers and wholesalers, stock levels in stocking centers, determining the flow of goods between facilities at different supply chain levels, and choosing the type of means of transporting goods between facilities. This is achieved through a three-objective mathematical model. The goals include minimizing the expected total cost in the supply chain, achieving the shortest travel time of goods in the chain, and at the same time minimizing the amount of deviation from customer demand. The presented model tries to pay attention to environmental uncertainty and consider different operational scenarios, as well as the possible approach in important parameters. This takes into account the product life cycle, the different rate of spoilage of the goods in different storage facilities, the different capacity of the facilities in different scenarios, and considering different methods of product transportation with different rates of product spoilage. All of this aims to cover the lack of previous research in the field of perishable goods supply chain design. Considering the multi-objective nature of the model and the need to create flexibility in decision-making for decision-makers, this research uses Normal Boundary Intersection (NBI), which allows decision-makers to choose the most optimal solution according to the importance of different goals. GAMS 24 software and MILP solver were used to solve the mathematical model.
Materials and Methods
This study presents a multiobjective model for designing a four-echelon supply chain (SC) in the strategic and tactical levels for fixed lifetime perishable products. The targeted SC levels include production plants, distribution centers (DC), wholesalers, and retailers. The locations of the plants and retailers are predetermined, while the locations of DCs and wholesalers will be selected from potential locations. The elaborated model seeks to minimize the total cost and product transportation time in the SC and minimize expected demand deviation as well. The Normal Boundary Intersection (NBI) method is employed for solving the model, and GAMS software is used to determine the optimal values of decision variables.
Results
This study utilizes a case study of an Iranian broad dairy company that produces eleven product groups. Data for the study were collected from historical company records and expert interviews. According to the opinions of the experts, three different operational scenarios have been extracted, and the data related to each scenario, especially the customer demand, has been estimated according to historical data as well as the corrective opinions of the managers. The results of the proposed mathematical programming model showed that changes in demand did not have unexpected effects on the values of the objective function and did not change the general trend of the answer to the problem. On the other hand, changes in the percentage of perishability of the product had far less impact on the values of the objective functions as well as the membership function. The overall result is normal, and as a result, in general, these changes represent the stability of the model against the fluctuations of important parameters. A comparison of optimal results and reality reveals that the examined SC needs a redesign of its DCs and wholesalers' locations, and hybrid transportation methods should be used.
Conclusion
Supply chain design (SCD) of fixed lifetime perishable products at the strategic and tactical levels is indeed an important issue. By considering the research gap, this study developed a multi-objective and multi-level model for SCD of fixed lifetime perishable products, and new concepts such as varying perishability rates in storage and transportation facilities are considered. On the other hand, with regard to environmental uncertainty, important parameters such as demand and capacity of facilities are considered as probable parameters. Adding environmental and social factors as new objectives, hybrid transportation methods, and horizontal interactions in the same SC levels can be considered for model development. In order to solve the proposed model, NBI has been used, which has significant advantages compared to other solution methods. By turning the answer of the optimization model into a kind of decision-making problem, this technique gives flexibility to the decision-maker to choose the best solution for their supply chain design according to the weight of each goal. Also, the decision-maker can redesign and increase the adaptability of the supply chain by changing the important parameters of the problem over time.
Laya Olfat; Maghsood Amiri; Iman Raeesi Vanani; Mansour Esmaeilzadeh
Abstract
Today, it is difficult for organizations to survive without improving supplier performance and supplier relationships or gain competitive advantage. Therefore, suppliers must be managed and developed to meet the needs of the producer company. On the other hand, the supplier's development requires the ...
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Today, it is difficult for organizations to survive without improving supplier performance and supplier relationships or gain competitive advantage. Therefore, suppliers must be managed and developed to meet the needs of the producer company. On the other hand, the supplier's development requires the introduction of precise and comprehensive criteria. The aim of this paper is to identify the dimensions and categories of supplier development based on the criteria related to it, using the Meta-synthesis method. For this purpose, first we selected 102 studies from 136 studies, coding their texts with Atlas TI software, 23 concepts were identified for the criteria. Subsequently, through the analysis of literature, the identified concepts were classified into four tangible, intangible, environmental, and external dimensions and internal dimensions. To verify validity, triangulation of data, sources and researcher has been used. The content validity ratio and content validity index were calculated by a survey of automobile industry experts, four of the criteria were directly eliminated, and modifications and modifications were made on the criteria, and finally, 17 criteria for the development of suppliers in the automotive industry were finalized. The amount of Kappa coefficient obtained shows the reliability of the identified criteria. Finally, a two-dimensional model is proposed for the supplier-development criteria. Due to the lack of categorization of the criteria related to the supplier's development in previous studies, and in particular in domestic research, the identified criteria and their categorization can be useful for researchers in this field.
Ahmad Ahmadi; Abolfazl Kazai; Mohammad Naghizadeh; Maghsood Amiri
Abstract
Following Chesbrough's statements of open innovation as a spectrum rather than a dichotomy, many studies have been conducted to reflect the dynamics in its implementation in the form of typologies, modes, themes, and mechanisms. These studies, with considering only some aspects of the innovation process, ...
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Following Chesbrough's statements of open innovation as a spectrum rather than a dichotomy, many studies have been conducted to reflect the dynamics in its implementation in the form of typologies, modes, themes, and mechanisms. These studies, with considering only some aspects of the innovation process, have tried to develop a method for classifying and providing a model for adoption of open innovation. After reviewing the literature and interviewing with experts, the components and factors in each implementation step were obtained. Finally, to analyze and plot the interrelationships between the various components of the open innovation model DMATELE technique was used. Consequently, the open innovation model was determined in the study company. This model is the result of a chain of decisions in relation to each component of OI model within the phases of the innovation process. The decision chains include: selecting the “pre-print” domain as content of the model, choosing the direction of “market driven –invitational” for actors, and choosing mechanisms for increasing “absorptive capacity”, “transformative and connective capacity”, and “desorptive capacity.”
Samira Parsaiyan; Maghsoud Amiri; Parham Azimi; Mohammad Taghi Taghavifard
Abstract
The increasing concern about the deteriorating effects of supply chains related activities on the environment has led to the growing attention to develop green closed-loop supply chains in order to minimize greenhouse gases emission. This paper presents a green closed-loop supply chain model developed ...
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The increasing concern about the deteriorating effects of supply chains related activities on the environment has led to the growing attention to develop green closed-loop supply chains in order to minimize greenhouse gases emission. This paper presents a green closed-loop supply chain model developed under the demand uncertainty aiming at minimizing total cost and total CO2 emission across the supply chain, and maximizing the product’s market share in the presence of a competitor. In this regards, an agent-based market model is developed to estimate the demand’s parameter function then a hybrid simulation model which integrates agent-based and discrete event simulation modelling approaches is designed to simulate the closed-loop supply chain which is the novelty of this paper. Then, scenarios are created using Taguchi design of experiments (DOE) method, and are executed with the market model and the supply chain model to capture total cost, total CO2 and market share. A decision matrix is configured using scenarios and recorded results for three mentioned criteria and ELECTRE and SAW methods are used to rank scenarios and select the best one. The other contribution of this research is its comprehensiveness in considering variables related to three categories of inventory replenishment policy, marketing mix (price and advertisement) and transportation. An automotive industry case is provided to demonstrate the capabilities of the model and its applicability and effectiveness in resolving real-world problems.
Majid Hooshmandi Maher; Maghsoud Amiri
Abstract
In most industries the cost of raw materials and product components constitutes almost 60% percent of a product cost (in some industries up to 80%). In this condition، proper sourcing can play a key role in an organization's efficiency and effectiveness، because it has a direct effect on cost reduction، ...
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In most industries the cost of raw materials and product components constitutes almost 60% percent of a product cost (in some industries up to 80%). In this condition، proper sourcing can play a key role in an organization's efficiency and effectiveness، because it has a direct effect on cost reduction، profitability and flexibility of a company. In this paper، to determine the optimal order quantity, multi supplier،multi product and during several periods، shortage and surplus،incremental discounts، multi objective and multi criteria nature of the problem، uncertainty in demand، lead time، fixed order cost، supplier quality level and every period budget are being considered. To incorporate the effective criteria in mathematical model، analytic network process approach has been used. After developing the robust multi objective mixed integer programming، a numerical example is presented. Finally, the results and suggestions for future studies are presented
