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  A Production system with push control system uses materials requirements planning (MRP) to plan purchasing and manufacturing physical resources. Therefore a material planning system provides a basis for scheduling production and purchasing materials. Firms are looking for a way to deal with fluctuations causes by environmental uncertainty, which include fluctuations in demand and supply of raw materials. Using safety stock which is a certain amount of goods or materials kept as inventory to deal with uncertainty is one way to deal with fluctuation issue. Despite the safety stock importance, there is no comprehensive framework for decision making about this issue. The aim of this paper is to provide a dynamic model for MRP system. By applying this model, a suitable policy of safety stock is achieved. Then, the appropriate amount of safety stock can be obtained and total inventory cost can be reduced. A system dynamics approach is used to simulate the model and demand and lead time are considered probabilistic. After designing the model, different scenarios of safety stock have been proposed. Used criteria for selecting an appropriate scenario is total inventory cost, and finally a scenario in which the total inventory cost is at its lowest amount would be chosen as the best scenario.    
 
 

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The advent of new technologies is constantly evolving in today's societies, while information technology is the most effective of these activities. Since information technology can have a devastating impact on the environment, protecting the environment from these threats has added to the concerns of organizations, and as a result, the Green IT debate has become a topic of the day. Different models and methods have been used to explain the various dimensions of the maturity of green information. In this research, a dynamic model was developed to examine the relationship between components and determine the appropriate strategy to reduce energy consumption and thus increase the maturity level of green information technology in the organization. Since the banking industry is closely related to information technology, all Iranian banks have been investigated in this study. First, various components influencing the maturity of green information technology have been identified and their initial level and factors influencing their increase or decrease have been determined, then Causal loop and Stock and flow diagrams are illustrated to explain their relationships. In this regard, variables related to human factors and factors related to technology have been investigated. In the end, after testing and simulating a dynamic model, several scenarios have been proposed to improve the situation in the banking industry and to reach the highest level of maturity of green information technology. Keywords: Green Information Technology, Green Technology Maturity, System Dynamics, Banking Industry

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Just in Time (JIT) production systems are introduced for production and supply of goods and services with minimum inventory. The goal of this paper is present a sample of system dynamics modeling application for analysis and improvement of JIT system's behavior. In this paper relations between demand of products, quality of produced goods, inventory, maintenance of machines and facilities, production rate and supplier's efficiency are investigated in a dynamic system. In the first section problem definition, dynamic hypothesis, causal diagram and flow diagram of system are discussed. Afterwards behavior of the model is inspected from different views by developing a dynamic model.

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Among flows in every supply chain (finance, information, and material), material flow according to its part in product cost is very important. Many studies in the field of material flow showed that material flows are often single level. This study offers a comprehensive model for appropriate order assignment in different levels of supply chain according to minimizing related cost to with genetic algorithm method. Results based on genetic algorithm is compared to other common pattern search methods such as Latin Hypercub and Mead-Nelder. The evidence shows that genetic algorithm method is the best method among other methods.

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The relationship between privatization and economic growth is the main focus of this research. A system dynamics approach and theoretical relationships in macro economics to growth patterns is used to study the impact of privatization through stock market on economic growth in Iran. The output calculation is done by human capital indicators such as the cost of investment in research and development, life expectancy, the rate of education and standard of living which are regularly published by the United Nations Organization. For estimating the rate of privatization, private investment and demand for stock, the statistics are provided by the Central Bank of Iran, the Organization for Privatization and the Stock Market Organization. Using a system dynamics approach to macroeconomics and the above-mentioned indicators the interaction and relationships between privatization and economic growth is explored in this paper. This approach which was firstly introduced by Forrester in 1973 can potentially improve and reform the unsuitable monetary and fiscal policies. In this regard the VENSIM and econometrics software packages are applied to simulate the results till the year 2020. Moreover, the economy is divided into many sections as stock market, investment and production. The results indicate that the rate of privatization in the stock market has a positive effect on economic growth. Finally, it is believed that more attention to private investment can result into increase in economic growth.

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This article analyzes the welfare loss of pollution resulting from production in Iranian economy using an augmented growth model and designing an economic-ecological system dynamics model. The main elements of the model include social welfare, welfare loss, production, physical and human capital accumulation, pollution accumulation, income distribution, and initial conditions. Regarding 2005 as a base year, the time path of per capita pollution and related welfare loss are simulated for the Iranian economy over the 20-year time horizon. The simulation results indicate that with persistence of the status quo, per capita pollution and its welfare loss rise with positive rate. Therefore, the goals of sustainable development will not be achievable. Hence, further improvement of the environment requires government intervention through the appropriate policies. The results of sensitivity analysis of policy parameters show that clean technology diffusion and environmental preferences of producers have negative effects on pollution emissions per capita and economic welfare in Iran, while strengthening environmental preferences of consumers may raise the social welfare loss of pollution. In addition, pollution per capita and its welfare loss are of most sensitivity to environmental preferences of producers, environmental preferences of consumers and clean technology diffusion, respectively. Policy-makers may regard these results in planning to achieve sustainable development objectives.  

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The use of System Dynamics Modeling in Supply Chain Management has only recently re-emerged after a lengthy slack period .the propose of this thesis is to use knowledge and techniques in implementation based on recent research .At first we have given an overview of supply chain management and system dynamics and then presented a taxonomy of research and development in System Dynamics Modeling in supply chain management. In this research we have focused on a supply chain as a case study Which produce and distribute healthy products and its main company is darugar. we used System Dynamics techniques to know effective variables in our supply chain and understand how to improve its performance .we started simulation model design by explaining dynamic hypothesis and continued by creating casual loops, stock & flow diagrams and mathematical formulation .our model was tested by famous dynamics and statistical techniques and then we started to investigate causes of supply chain’s behavior by sensitivity analyses. when we understood the main factors and their interactions completely we started to suggest three policies due to supply chain indexes to improve its performance .the policies are missed sale reduction ,inventory reduction and correct information receive which all causes improvement in introduced indexes in our research .what we achieved of this research was our ability of predicting results before any changes in parameters ,relationships or structure of supply chain and it is so important due to its high degree of complicity.

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Appraisal and calculate productivity of the industrial groups with applying of system dynamics approach in 1404 horizon. In this paper, industrial productivity was calculated in 1404 horizon with usage of system dynamics model. For this purpose, with regard to behavior of the effective variables and data of 1380 to 1388 years, the productivity model was designed and simulated.The result showed industrial productivity from 1380 to 1388 years always decreasing and this trend because increasing input production, will be continuing from 1389 to 1396 years, but from 1396 to 1404 horizon this trend will be increased. It should be noted that the productivity of the manufacturing process, labor productivity is lower fluctuation from than capital and energy. With regard to role of industrial productivity in value added, the appraisal of policy changes showed that increase of 1% annual productivity rate in industrial sector in 1404 with ratio to bas year, lead to increasing 3.5%.value added

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  There are too many different reasons for organizational project failures. Non-supportive management, internal resistance, and situational changes can be mentioned as some of the most important reasons. In formation sciences (IS) projects follow the same rules. Because of their considerable effect on the quality and quantity of organizational output, this article tries to propose some solutions to minimize the probability of such failures in Iranian organizations. Informatics Services Corporation (ISC) as the largest e-banking company in Iran has been chosen as the case of study. Vensim software (Version 9) was applied to simulate the real situation available in ISC. By testing different solutions, it was conducted that the most effective ones are: continuous training, establishing sustainable management systems via process clarification and procedure deployment, helping to ameliorate contactors' financial condition, and clear written contractual relations instead of verbal agreements in all phases of the projects. The major advantage of this article is its concentration on project gap.      

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One of the most important functions of manufacturers and producers related to supply chain management issues and decisions is supply chain order management. However, there are several problems in this regard like (a) selection of best order portfolio between the received orders, and (b) detailed and accurate calculation of order fulfilling costs. Accordingly, in order to increase model confidence in the research, we used both mathematical optimization and system dynamics to design the order management system of an Automakers Company supply chain orders. In phase 1, using the mathematical optimization approach, we determined optimum order portfolio of the received supply chain. In phase 2, using phase 1 output and system dynamics approach, we determined the costs of order fulfillment. Both traditional and activity-based costing techniques were used to calculate cost parameters and objects. Ultimately, in order to select better costing approach, we compared the  two approaches. According to the results, ABC is better costing approach than traditional.   

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To encounter with Knowledge Management, the organizations should select appropriate knowledge strategy and knowledge management strategy. There are different methods for developing these strategies. In this study a System Dynamics model developed to select and integrate both strategies. In the proposed model organizational factors such as business strategy, structure, culture, human resource and IT infrastructure have been considered. On the other hand, from the dynamic approach perspective, the knowledge creation processes and the level of explicit or tacit knowledge have direct impact on selected strategies. In this paper all the stock variable and their initial value have been identified then the flow variable and theier increasing/decreasing rate have been determined and casual loops and stock and flow diagrams was proposed. At last after simulating and testing the dynamic model, different scenarios and policies have been presented for the case study. The results indicate improvement in both KM strategy and knowledge strategy. Keywords: knowledge management, knowledge management strategy, knowledge strategy, system dynamics

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Sustainable development has become a major concern for policy makers and planners in the world today. Sustainable development is composed of three main aspects: environmental, economical and social. transportation has significant economical, social and environmental impacts, and is an important factor in sustainability. urban transportation system is a complex system with multiple variables and nonlinear feedback loops. Transportation can not be rated as an independent criteria.This article aims to present a dynamic model for urban transportation system concerning sustainable urban transportation in a way that by using this model the complicated and dynamic nature of urban transportation system will be understood and the impact of policies will be analyzed. So the best has been done in the article using systems dynamic approach, a completed and integrated Model for Tehran transportation system be introduced considering sustainable urban transportation system concept and the system dynamic conduct be analyzed. In continue some policies have been introduced by model simulating in order to increase urban transportation system utility and urban traffic parameters improvement. This model has been analyzed in vensim software using the data from Tehran. Results show that compound performance of presented policies has a great impact on urban transportation systems and Tehran traffic parameters improvement.

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As regard the increasing complexity and challenging problems at today organization demand developing suitable decision models. This research is aimed at utilizing whole systems approaches at better implementation strategy in this regard due to their power in resolving complex and dynamic organizational issues, and also responded some of shortcomings of existing in other strategy implementation models and methods. Since all systems methodologies are inherently restricted to determined problem domains, using total systems intervention (TSI) meta-methodology to strategic development road map, because it is totality and capability to use several system methodologies in combination. By proposed road map has made methodologic process for strategy formulation and implementation and also reached learning organization and scheming culture by applying appropriate system methodologies. Also this road map smoothly decreases the gaps between strategic and function layers in organization by ensuring a consensus between stakeholders and actors. According to the phase of TSI, at first, barrier of strategy implementation were investigated then soft systems methodology (SSM) and system dynamics (SD) selected as chief methodologies, by way of applying SSM, determine functional strategy and SD prioritize strategies, and resource allocation. The end phase, TSI was at public organization implemented, and the initial steps of road map were explored. At the end, proposed system model and final road map for strategy implementation with ten steps and two main action and investigated that`s validity. The action plan and system of performance indicators were reached via utilizing this road map in public organization. 

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It is important to identify sources of industrial investment growth from policy planning perspective, due to importance of manufacturing industries as the engine of economic development. SME formation is one of these sources that its impact on investment process with various methods has been studied. However, each of these studies used their specific angle and in some cases, these studies have reached different conclusions. On the other hand, many of the previous studies have applied statistical approaches and short-term, medium-term and long-term consequences of the solutions that have proposed by these studies has not considered at the same time. Therefore to address this deficiency, the holistic approach (system thinking) used to study impact of SME formation on investment growth. System Dynamics (SD) method used as a tool for implementing system thinking approach in order to use its capabilities in complex systems modeling and for achievng suitable results from simulation model. The population is Fars province in Period of 1360-1410. Vensim software has used for modeling and simulating. The results from the simulation of designed model showed, there is direct and interactive relationship between SME formation and amount of industrial investment.

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Problem definition is the most vital and important step in system dynamics approach. It is the basis for other steps of dynamic modeling and one of the main conditions in the effectiveness of modeling and its success. Considering its importance, there is scant literature on process of problem definition and attributes as well as indicators of dynamic problems. With aims to explain the problem definition, this article creates problem definition framework through the systematic and structured process by extracting the indicators and factors that determine a dynamic problem. At this point all the articles listed at the first two rounds of system dynamics research conferences in 1976 and 1981 and also 33 around of the system dynamics conference from 1983 to 2015 as well as the Journal of System Dynamics Review (SDR) and scientific databases include Elsevier, Wiley, Springer and Emerald were examined. Finally, a framework was designed with 6 indicators including structure of the problem, problem`s stakeholders, border of problem, problem complexity, dynamics and nature of the problem, which altogether consists of 24 indexes. A comprehensive framework for the diagnosis of dynamics problem is main finding of this paper.

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Importance of manufacturing capabilities for achieving competitive advantage was raised by Skinner. He stated that manufacturing function typically is either a competitive weapon or a corporate millstone. This paradigm set forth by Skinner and refined by scholars who followed him, express that in order to plan successful strategies, managers should pay attention to effects of manufacturing capabilities (Quality, Delivery, Flexibility and cost). Because of trade-off among level of each capability, they should set to the point which has most profitability for the firm. Empirical works of Ferdows, Demeyer and Nakane proceeding The Cumulative Model, this theory suggest that trade-off among capabilities isn’t always feasible, but firms follow a pre-specified order for building manufacturing capabilities as first quality, then dependable delivery, third cost reduction and finally flexibility, where effect of improving each capability on other capabilities could transit to supportive effect. In researches on manufacturing capabilities based on cumulative capabilities theory, effect of innovation is missed, and by studying literature review, we found that innovation can play a key role in creating sustainable competitive advantages. On the other hand, globalization and shorter products and technology life cycle, results in paying a lot more attention to innovation. In our study, we added innovation to the previous model which exists in the field of cumulative capabilities. The aim of this research is to find out the relationship between manufacturing capabilities using structural equation modeling on Saipa Corporation.

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An examination of international political economy history shows that discovery of huge oil reservoirs has been playing an important role in defining and supporting the countries national interest. Undoubtedly, oil reserves in Iran are considered as intergenerational resources and maintaining intergenerational justice as well as enhancing national interest in the long run. These are indisputable commitments which are the main goals and missions of Iran governors. In this research, focusing on the economic aspect of the national interest and by using systems dynamic methodology, dynamics changes of Iran’s national interest are modelled considering developments in the oil industry and market. The structure of production capacity formation, amount of production and revenues of domestic and international sale of oil and oil products are investigated and modeled and variables related to economic national interest are formulated. Simulation results described in five scenarios as follows: growth in the oil market, current status, downturn in the oil market, OPEC market share target, and OPEC revenue target. According to results, increase in domestic prices of energy carriers to international prices and the increase of the budget share for investment in more value added areas in the oil industry are recommended to increase national economic benefits.

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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.