Keywords = simulation

Application of system dynamics in assessing sustainability performance of LARG supply chain in the automotive industry

Volume 25, Issue 1, Spring 2021, Pages 1-24

Mehdi Izadyar; Abbas Toloie Eshlaghy; Mehri Zahra

Abstract Improving sustainability in supply chains is one of the strategic objectives in the current business. Firms have been adopted new management strategies to achieve sustainability in the manufacturing supply chain. Therefore, it is essential to assess the sustainability performance of the newly implemented management strategies. The purpose of this paper is to provide a model for assessing the sustainability performance of LARG supply chain management practices in the automotive supply chain using the dynamics system. In this paper, LARG supply chain management practices was identified by reviewing the literature and interviewing experts and were prioritized using fuzzy DEMATEL and fuzzy analysis network process and was presented as an integrated approach to LARG practices. Finally, the dynamic system has been used to assess the dynamics of LARG supply chain management practices and their impact on sustainable performance in the supply chain. The findings show that improved scenarios flexible transportation and just in time lead to a more sustainable supply chain. The results of these scenarios show sustainability improvement in the supply chain Also the results show that lean strategy is a very important for achieving sustainability in the supply chain. The proposed model helps industry managers and decision makers to identify the results achieved from implementing LARG supply chain management practices and improving effective practices on sustainability in the supply chain by adopting policies.

Analysis of the Service Process of Insurance Issuance System Life and Securing the Future with a Discrete Event Simulation Approach and Scenario Writing (Case study: Pasargad Insurance Company)

Volume 24, Issue 4, Autumn 2020, Pages 19-47

Reza Shakerin; Abbas Toloie Eshlaghy; Reza Radfar

Abstract Customers are the most important resources of service companies, and so there is no doubt that the condition for achieving profitability of insurance companies depends on analyzing issues related to customer satisfaction and increasing the productivity of the servants. One of the most important factors that insurance companies face with customer satisfaction in providing insurance services is reduce process time of the issuance of insurance policy to customers. This issue has rarely been considered by insurance companies, therefore, in this research, it has been tried to using simulation of the existing system and observing the results of the simulated model, a solution should be provided to improve the duration of the insurance issuance process. After compiling the model in the software environment, were analyzed the results of the implementation of the discrete-event simulation model and tested to validate the model, and after the simulated model was found to be valid, were developed scenarios for improvement system. The results showed that with the change in each parameter of the number of users issuing the insurance policy, the time of customer referral to the expert physician and the time of response of the specialized tests and the time of appointment of the insurance representative to the insurance policy issuing unit, the duration of the issuance of the insurance policy decreased, and eventually Will lead to improved service delivery and increased productivity, reflecting the effectiveness of the discrete-event simulation technique and the development of operational study methods in the service sector.

Investigating macro management attitudes in citrus production of Iran using a system dynamic modeling approach under R&D interventions and sustainability aspects

Volume 23, Issue 4, Autumn 2019, Pages 55-79

Nasser Safaie; Armin Cheraghalipour; emad roghanian

Abstract Todays, in addition to the economic aspect, paying attention to the social and environmental aspects has contributed to the sustainability of the supply chain. On the other hand, macro management attitudes for profitability are considered as a key component in the robustness of various industries, including citrus production. In this research, using a system dynamics approach we examine the effect of profitability on its related factors through a systematic view. For this purpose, a system dynamical model is presented and in order to validate it, its behavior is compared with historical collected observations. Statistical analysis indicates that the simulated model is adhered to its actual state. To further explore the Monte Carlo simulation is performed for sensitive variables, and finally, the proposed model is implemented under different employed scenarios. In different times of simulations have shown that several interventions such as research and development (R&D) can increase the citrus production and other key variables.  

Analysis of a bank queuing system and reducing the waiting time for customers by simulation and design of experiment approach

Volume 22, Issue 1, Spring 2018, Pages 95-118

hossein talebi; maghsoud amiri; parham azimi

Abstract One of the most important goals moving toward banks customer satisfaction is reducing waiting time in branches. Banks are queuing system including that long queues of customers will cause Increase customer waiting time and decrease satisfaction. One of the effective solution for reducing waiting time is optimizing number of service personnel in each sector which in addition to reduce the waiting time, it has increases employee engagement. In this paper, simulation and experimental design method has been applied to this topic. This paper is developing a model with two objectives; Minimizing customer wait times and maximizing working time of employees. First, the current status of MELLI bank branches is simulated by ED, then Improvement scenarios is implemented by DOE methods and finally model is solved by design-expert software. The results show that most favorable option is one electronic and clear employee and five Cashiers employees. Using this method resulted in reduced waiting time by 32 percent.

Business Processes Design of Small and Medium Enterprises of Perishable Items in order to Determination of Optimum Production Policy with Simulation Approach

Volume 19, Issue 3, Summer 2015, Pages 7-35

Jalil Heidary Dahooie; Seyed Mojtaba Sajadi; Fereshteh Tavan

Abstract In today's competitive world, production and inventory control in small and medium enterprises (SME) is considered as an important issue by managers, because of the influence of factors such as fluctuations in demand and failure of machines. Network Failure Prone Manufacture Systems (NFPMs) are type of production systems that failure of machines is assumed for them. In this paper, a multi-product network failure manufacturing system with perishable items is studied. The production control policy is based on the hedging point policy that contains producing and maintaining of products in order to respond to demand and avoid shortages. In this system, demand is constant and shortages (backlog and lost sale) have been allowed. The main goal of this paper is to determine the optimal production rates that minimize expected value of total production, holding, shortage, and perishable costs. Because of uncertainly and complexity of these systems, simulation optimization has been done using ARENA software. Finally, numerical example will show the efficiency of the proposed approach.

Optimizing the Number of Bank Branches Equipment by Using Simulated Annealing Algorithm

Volume 18, Issue 4, Winter 2015, Pages 65-86

Parham Azimi; Khalil Sajjadi

Abstract One of the main objectives in Bank customer-orientation is to reduce the waiting time of customers at the branch. One solution is optimal utilization of capacity and adequate facilities. Employing more than enough may cause additional costs to the Bank. This paper uses a new methodology to determine the optimal combination of equipment and facilities in Bank branches.  For this purpose, mathematical model consisting of minimizing the objective function and some constraints was developed. We solved this model by using Simulated Annealing algorithm of answers or simulation scenarios with respect to the objective function so that the optimal plausible scenario is chosen. In this method, first possible scenarios are made by considering issue constraints, using MATLAB and simulation software ED in 50 times (each time 8 hours). Finally, with respect to the combined equipment and facilities of each scenario, the costs of using equipment  and  the cost of losts customers  were calculated, and a scenario in which 4 Rial  booths,  2 exchange booths, 3 facility booths, and two ATM booths  are used with the lowest  cost, WAS chosen as  the optimal scenario.

Reduction of lead-time Production by Using Value Stream Mapping and Simulation

Volume 18, Issue 4, Winter 2015, Pages 161-181

Akbar Ghadrdan; Haydeh Mottaghi

Abstract Most of the organizations employ lean production techniques in a separate manner for eliminating the waste. However, in some cases, in spite of spending huge amount of costs for implementation of these techniques, they could not reach the planned benefits. Therefore, creating a mechanism in order to inform managers regarding the benefits of waste elimination prior to technique execution is one of the vital issues in implementation of these techniques. In this case study, lean production tools have been introduced in a systematic manner by applying value stream mapping, which is one of the main lean production tools in identifying wastes and improvement of opportunities. Furthermore, in order to analyze the results of deploying the above techniques, two simulated models for the current and improved situations have been developed. Finally, by executing the simulated models, two systems have been compared on the basis of key measures, which are lead time production, inventory in process, and unnecessary transportation. The results showed a significant decrease in waste.

Process Reengineering by Using Simulation Approach (Case Study: NIORDC)

Volume 16, Issue 4, Winter 2013, Pages 145-170

Gholamreza Bodaghi; - -

Abstract In this paper the As-Is model of the organizational affairs process of the NIORDC (National Iranian Oil Refining and Distribution Company) was drawn by the use of BPMN modeling tool, and then its simulation model was modeled by using SIMPROCESS simulation software and relative parameters were defined. Necessary scheduling in defining simulation parameters were extracted and set according to available organizational documents and archives. Afterwards, justification and verification of simulation models were tested by using statistical tests. In the next stage, several reengineering scenarios were suggested and designed according to BPR rules, experts' viewpoints, brainstorming sessions, and the facts found during project implementation. These scenarios were modeled by using BPMN modeling tool, and then their simulation models were designed. Since these scenarios are about the future situation of the process, only some justification and verification steps of simulation models were considered. Finally, on the basis of defined indicators in the beginning of the project, values of them were calculated for each scenario and each one was analyzed on the basis of cost-benefit analysis. At last, these scenarios were ranked by using AHP method and their scores were counted in order to suggest to the management.

Developing a Model Based on Simulation for Documentation and Analysis of Inter- organizational Relationships

Volume 11, Issue 20, Autumn 2007, Pages 31-58

Adel Aza; Azim Zarei; Shaban Elahi; Habibalah Ranaei

Abstract Today's organizations face a complex set of needs of their stakeholders. They cannot satisfy those needs in a good manner because of economical rationality or inability to prepare suitable equipments. So inter-organizational relationships have been choosen as a strategy which nowadays attract much attention. In fact, each organization has a set of interorganizational relationships voluntarily or involuntarily with other organizations which many organizational advantages and disadvantages have roots in such a inter-organizational relationships. Therefore, the Present research aimed at developing a simulation based model to study inter-organizational relationships. In this model, inter-organizational relationships are documented with process approach, and then. analyzed based on volume, time, human recourses, mutual dependency network and decision. According to the analysis results, "to-be" process is redesigned. These changes are suitability analyzed with simulation and implemented if they are confirmed. Finally this model has been implemented in Agriculture Industry Bureau of Jihad -Agriculture Ministry.

Application of Simulation in Uncertainty of Multicriteria Decision Making

Volume 10, Issue 4, Winter 2007, Pages 231-251

Mansour Moemeni; Majid Esmaelian

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 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.