supply chain management
fateme khanzadi; Reza Radfar; nazanini pilevari salmasi
Abstract
Nowdays, supply chain specialists are looking for the integrated development of the supply chain model in order to increase the competitiveness, effectiveness and reduce the problems in the supply chain. They always seek to identify and develop this process so that they can cover more aspects of the ...
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Nowdays, supply chain specialists are looking for the integrated development of the supply chain model in order to increase the competitiveness, effectiveness and reduce the problems in the supply chain. They always seek to identify and develop this process so that they can cover more aspects of the chain. Adding effectiveness indicators along with LARG indicators and using the basics of the dynamic system to improve the efficiency of the supply chain is one of the innovations of this study. At first, by using research literature and studies, 12 headings of indicators were selected as LARG-E indicators. Then, with the Fuzzy Delphi method, the relationships and importance of each of these components were determined, and more important variables were modeled for further investigation. With using the concepts of dynamic systems, causal loops were drawn. Then, to check the function of the model, dynamic hypotheses were developed with the opinion of experts. In the next step, the flow diagram of the model and also the validation tests of the proposed model were done. Finally, by examining the outputs obtained from the proposed scenarios, it was found that most of variables have better behavior in LARG-E approach.IntroductionIn recent years, with the addition of various competitions in the world markets, many researches have been conducted to use new technologies and researches in order to improve the production process and increase the effectiveness of these competitions as much as possible (Mohghar et al., 2017). All the goals that work in this field increase the competitiveness of the organization. This competition is by reducing costs, being present in the market and satisfying the customer. To increase profits, protect the environment, keep the markets stable and meet the expectations of customers, organizations should be provided using the existing environments in a set of customers (Pisha et al., 2016). Use chain management requires the use of new facilities and improvements to previous findings such as lean, agile, resilience and green to increase speed and competitiveness, selection and decision-making to achieve the organization and maximum effectiveness.Today, supply chain specialists are looking for the integrated development of the supply chain model to increase the effectiveness and efficiency of the supply chain in order to increase competitiveness and reduce supply chain problems. In this case, there is a consensus among experts that there is no comprehensive model. All the mentioned cases make it inevitable to design a comprehensive and effective model for the supply chain. The verifiable issue is the conflicts and the non-alignment of all the indicators of the paradigms with each other. LARG paradigms, without considering the spirit of effectiveness in each supply chain, cannot fully protect it against continuous changes in the competitive market arena. A comprehensive model that pays particular attention to effectiveness while implementing LARG paradigms has not been examined in the literature review and the consensus of experts. Therefore, in this research, we are looking to design a comprehensive model in a LARG-effective manner so that the effect of various LARG-effective indicators on the performance of the supply chain can be investigated. The integration of LARG paradigms has been studied a lot so far, but its development is based on the concepts of innovation effectiveness of this research, and in this way, the dynamic system approach was used.Materials and MethodsTo formulate a LARG supply chain, first the framework, indicators and variables of each LARG paradigm were extracted from the research literature, then in order to develop them with effective concepts, the effective supply chain was studied. In order to implement the fuzzy Delphi approach, based on the effectiveness indicators extracted from the subject literature and LARG supply chain approaches, operational indicators were provided to the experts participating in the research in the form of a questionnaire via email and after initial coordination. After collecting the completed questionnaires, fuzzification operations, fuzzy averaging and then de-fuzzification were performed. The results were brought to the attention of the participants and they were asked to apply their desired changes according to the obtained results. This approach reached the saturation stage in the third round and there was no change in the opinions of the participants and the consensus of the panel experts was the final and trusted output of the Delphi method. Finally, according to these weights, 9 quantitative variables had the highest importance and were used for dynamic modeling. The simulation stage is done with the help of software and Nasim. According to the features of modeling based on system dynamics, this approach was chosen as the main research tool in this study because there are linear relationships between the variables and there are nested feedbacks between the variables of the subsystems, the importance of simultaneously improving the performance in different layers of the producer, supplier and distributor. Which is one of the goals of this research, with this approach, it can be a very suitable tool for decision-making by the senior managers of the organization.Discussion and ResultsOrganizations are trying to improve their competitiveness by adopting Lean, Resilient, Green and Agile strategies; But as it was said, the implementation of these paradigms, which sometimes have conflicting results, requires a new integration and index to align the goals. So far, many researches have been done by merging two or more paradigms, the combination of all 4 paradigms called LARG has greatly helped to improve the performance of supply chains, but in this research, in order to improve the conflicts between paradigms, a new concept of spiritual effectiveness was given to the supply chain. Understanding the dynamics of applying the above four strategies and their effectiveness was done using the dynamic systems approach. In this research, the indicators of the LARG supply chain were defined based on theoretical foundations and interviews with experts; then the effectiveness indicators were placed next to them. These indicators were implemented in the printing and ink industry. In this way, an effective LARG integrated system was defined; then, using a dynamic model, dynamic hypotheses were first defined and state and flow diagrams were drawn. After correctness of the model and validation of the model, two scenarios were examined for 8 important variables. After applying the scenarios, the performance of LARG and effective LARG was compared. By applying each scenario in the designed model, it was possible to check the effect of new indicators on the variables and their behavior.ConclusionsAs a result, if the components of the effective supply chain are properly integrated with the LARG concepts, they integrate the conflict that may exist between the LARG paradigms and play the role of synchronization and improvement as a ruler and standard. The effective management of the LARG supply chain may not be defined as an independent variable, but it is a result of variables and indicators that improved performance in most cases.
production and operations management
Majid Shakhsi-Niaei; Fateme Ghayoor
Abstract
Aggregate production planning is a multi-objective problem which is influenced by managerial preferences which is rarely considered with these preferences in many researches. In this paper, a multi-product multi-objective aggregate-production-planning model has been proposed and implemented in an industrial ...
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Aggregate production planning is a multi-objective problem which is influenced by managerial preferences which is rarely considered with these preferences in many researches. In this paper, a multi-product multi-objective aggregate-production-planning model has been proposed and implemented in an industrial ball-valves manufacturing company. In the first phase, preferences of various product groups have been determined via a multiple-attribute-decision-making method which is used as an input for the second phase. To do this, one of the outranking methods has been used because of the variety in the dimension and the nature of different attributes. In the second phase, a deterministic multi-objective mixed-integer mathematical model has been designed considering the needs of the company. This model not only concentrates on the benefits, but also considers the preferences of the products. The third objective function is decreasing work in process. To solve this model, ϵ-constraint method has been used leading to a set of Pareto-optimal solutions, enabling the decision-maker to choose the best solution by trading off between the three objective functions. So top managers are able to decide how to provide product preferences and how to decrease WIP products while the benefits remain reasonable. The results show that using the proposed approach in the case study has improved 35%, 28%, and 56% total benefit, total utility, and WIP products, respectively.
production and operations management
Hadi Mokhtari; Hossein Shirani
Abstract
Today, in order to maximize the productivity, sales and profits of factories, variousfactors must be considered. One of these factors is energy saving, which leads tosuccess in any businesses. Another important factor is rework in the productionprocess, which reduces waste and optimal use of resources. ...
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Today, in order to maximize the productivity, sales and profits of factories, variousfactors must be considered. One of these factors is energy saving, which leads tosuccess in any businesses. Another important factor is rework in the productionprocess, which reduces waste and optimal use of resources. In this research, a linearmathematical programming model has been developed for a multi-stage productionsystem considering energy consumption and the possibility of rework. The objectivefunction of the model is calculated from a combination of energy costs and rawmaterial costs, and the proposed model has three categories of balance constraints,demand constraints and time constraints. The balance constraints, the task ofcalculating the number of raw materials required and the amount of input materialsto each part of the production stage, the demand constraints are the task ofcalculating the number of final products, and the inventory and time constraints arealso the task of calculating the time available to the production of each product.A hypothetical production system is flow shop. To understand the proposed modelbetter, a logical example is designed and solved and analyzed using GAMS software. In the current situation , energy consumption is one of the concerns of policy makers in the fields of production and industry , and therefore this research with the proposed model , helps decision makers in manufacturing industries to ensure optimal energy consumption , optimal decisions in adopt multi -stage rework and production condition
Mohammad saeed Company; Parham Azimi
Abstract
In this study, the use of simulation technique in bi-objective optimization of assembly line balancing problem has been studied. The aim of this paper is to determine optimal allocation of human resource and equipment to parallel workstations in order to minimize the cost of adding equipment and manpower ...
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In this study, the use of simulation technique in bi-objective optimization of assembly line balancing problem has been studied. The aim of this paper is to determine optimal allocation of human resource and equipment to parallel workstations in order to minimize the cost of adding equipment and manpower among the stations and maximize the production output. In other words, with optimal use of resources, production output is maximized and therefore productivity become maximum. To this end, with optimization via simulation, the production line process is simulated in the form of a simulation model in the ED software. After validating the simulation model using design of experiment, various scenarios designed and run in the simulation model. Possible results for human resource and equipment variables, obtained by genetic algorithm are shown in a Pareto chart and have compared with the production line current situation
Majid Esmaelian; Sayedeh Maryam Abdollahi
Abstract
Course timetabling is an important branch of the general scheduling problem. The course timetabling problem as a step in the course planning process in universities is one of the challenges faced by managers in the field of education. The problem is defined as assigning university courses to specific ...
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Course timetabling is an important branch of the general scheduling problem. The course timetabling problem as a step in the course planning process in universities is one of the challenges faced by managers in the field of education. The problem is defined as assigning university courses to specific periods throughout a week for a given semester while satisfying specific constraints. In this study, we present two novel binary integer linear programming models for the university timetabling problem. Using a GAMS IP Solver, several experiments through each model are solved and the results (the number of the decision variables and solution time) are compared and analyzed. The computational comparison indicates that the second model can be used for modeling large-scaled problems and has less computational and size complexity. Therefore, the second model is applied to optimal scheduling the courses planned for the faculty of administrative science and economics (ASE) at Isfahan University for one semester and the results consist of table of courses planned for teachers, students groups, rooms and workdays are presented
Faezeh Asadian Ardakani; Ali Morovati Sharifabadi
Volume 10, Issue 26 , January 2012, , Pages 75-94
Abstract
One of the solutions for solving cutting stock problem in differentindustries, such as sheet metal, lumber, glass, paper and textile, isapplying ,Particle Swarm Optimization to minimize the waste ofrawmaterials. This article is intended to solve two-dimensional cuttingproblem. In these problems, larger ...
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One of the solutions for solving cutting stock problem in differentindustries, such as sheet metal, lumber, glass, paper and textile, isapplying ,Particle Swarm Optimization to minimize the waste ofrawmaterials. This article is intended to solve two-dimensional cuttingproblem. In these problems, larger rectangular plates, divided intosmaller rectangularsegments, aim to minimizing the number of usedplates or the waste of plates by considering demand. In this articlePSO is used. To enhance the efficiency of algorithm, and preventingoverlap in cutting problem, the CUL algorithm is used. In order toinvestigate the results of algorithm, new software has been designed.This software has two ways for solving the problem. First, it ends upwith optimized cutting pattern considering the number and dimensionof segments and, length and width of main plate. Also, there is apossibility to give different width to software, in this case, thesoftware gives the user the optimum cutting pattern and optimumlength of main plate in addition to optimum width
