• Journal of Korea Water Resources Association
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• v.43 no.7
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• pp.609-623
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• 2010

In this paper the feedback loop mechanisms that are inherent in the management of water supply systems were identified based on the system dynamics modeling methodology. As a result, a system dynamics (SD) computer simulation model that can be used to aid efficient management of water supply systems was developed. The developed SD model can be used to predict operating conditions of water supply systems including the effects of pipe maintenance on the entire system. The developed model is consisted of water supply, pipe maintenance and water supply business finance model. The operation and maintenance data from a study water supply system were used to verify the model and to predict the past and future operating conditions of the system. The policy leverage that greatly affects the operating condition was evaluated by the sensitivity analyses for the operational indices due to changes in the exogenous variables. It was found that while the pipe maintenance related exogenous variables had great effects on the leakage and conditions of pipes, they did not have great effects on the major operational indices such as revenue water ratio. It is considered that the social costs due to leaks and pipe breaks and the corresponding mechanism of propagation of the costs must be modeled to better evaluate the effects of pipe maintenance on the operational conditions of water supply systems.

• Journal of the Korea Safety Management & Science
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• v.6 no.3
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• pp.187-196
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• 2004

By successful establishment of Supply Chain Management System they should make the supply chains speedy and combine production information system with the outcome system and thus they reinforce the competition of the production system of local enterprises in accordance with the rapid decision making. Supply chain coordination improves if all supplier of chain take actions that together increase total supply chain profits. To design of Modularity by the grouping supplier, the proposed method is to develop the most appropriate production system models through the reflection of JIT system in the Supply Chain Management which is necessity of the times and its importance. The objects of this study is to develop the most appropriate production system Model and optimal profit model in the process line and to provide the enterprises with the models which are based on the Supply Chain Management.

• Proceedings of the Korea Society for Simulation Conference
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• 2000.11a
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• pp.142-149
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• 2000

Most of supply chain simulation models have been developed on the basis of discrete-event simulation. Since supply chain systems are neither completely discrete nor continuous, the need of constructing a model with aspects of both discrete-event simulation and continuous is provoked, resulting in a combined discrete-continuous simulation. Continuous simulation concerns the modeling over time of a system by a representation in which the state variables change continuously with respect to time. In this paper, an architecture of combined modeling for supply chain simulation is proposed, which presents the equation of continuous part in supply chain and how these equations are used supply chain simulation models. A simple supply chain model is demonstrated the possibility and the capability of this approach.

• Journal of Distribution Science
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• v.14 no.4
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• pp.21-31
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• 2016

Purpose - This study examines how consignment and Vendor-Managed Inventory perform as supply chain collaboration programs. By using three key collaborative features, this study defines the collaboration programs and develops theoretical models of different supply chain systems. Research design, data and methodology - This study conducts sophisticated analysis on the supply chain systems by applying simulation modeling based on time-phased operations. The simulation model represents a two-stage supply chain system where a supplier sells a single item to a buyer, and it incorporates various operations. Results - In general, the simulation outcomes support that more advanced collaboration programs outperform less advanced ones. The analysis on the simulation outcomes identifies the significant value of information sharing in both collaboration programs. The specific conditions where the particular collaboration system outperforms the others are recognized. Conclusions - The outcome of this study supports that the supply chain system can improve its performance by having more collaborative features. This study provides business practitioners with guidelines to identify the circumstances that the specific collaboration program can fully exploit its advantages.

• Asia pacific journal of information systems
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• v.7 no.1
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• pp.151-163
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• 1997

This paper deals with a reference model for a process-oriented parts supply company From the view point of SCM(Supply Chain Management), the model focuses on the integration of order management and manufacturing information. The model, considering the characteristics of manufacturing processes, separates the execution level from the planning level, and then introduces a virtual process to efficiently link the two levels. The model is operated to maximize its flexibility by the separation of planning and execution. A case study shows that our model significantly increases the productivity of the company.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.2
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• pp.113-127
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• 2006

We consider an integrated supply chain model in which multiple suppliers replenish items for a single buyer's demand. Also the buyer specifies a basic replenishment cycle and the suppliers replenish the items only at those time intervals. Namely, we propose a model to study and analyze the benefit by coordinating supply chain inventories through the basic replenishment cycle time. The objective of this model is to minimize the total relevant annual cost of the integrated inventory model. After developing proposed coordinated models, we suggest heuristics for searching the solutions of our models. Finally, numerical and computational experiments for each policy are carried out to evaluate the benefits of those models and the compensation policy is addressed to share the benefits.

• Proceedings of the Korea Society for Simulation Conference
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• 2005.11a
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• pp.65-70
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• 2005

Recently, Grid is embossed as a new issue according to the need of cooperation related to distributed resources, data sharing, Interaction and so on. It focuses on sharing of large scale resources, high-performance, applications of new paradigms, which improved more than established distributed computing. Because of the environmental specificity distributed geographically and dynamic, the most important problem in grid environment is to share and to allocate distributed grid resources. This paper proposes supply-driven strategies model that is applicable for resource management in grid environment and presents a optimal resource allocation algorithm based on resource demands. Supply-driven strategies model can offer efficient resource management by transaction allocation based on user demand and provider strategy. This paper implements the supply-driven strategies model on the DEVS modeling and simulation environment and shows the efficiency and excellency of this model by comparing with established models.

• Journal of Korea Water Resources Association
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• v.33 no.4
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• pp.447-459
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• 2000

Since the development of water resources is getting more difficult than ever before because of human-sociological condition, it would be necessary to develop a practically applicable technique for the management of water resources based on demand-side concept that could reduce unusable release for more effective and appropriate allocation of limited water resources. The objective of the study is to develop an optimal reservoir system operation model for water supply and energy augmentation by the combination of water budget analysis method in downstream area by MIP technique. The applicable study of the developed model was carried out and water supply capability of Nakdong river basin was re-evaluated by the developed model. The model has been found successful to guarantee appropriate water supply to the basin by means of deficit-supply management method and also turned out to be more practical tool for an optimal reservoir system operation model than other existing models.

• Journal of Environmental Impact Assessment
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• v.14 no.4
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• pp.157-164
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• 2005

Existing models that predict of Daily water supply include statistical models and neural network model. The neural network model was more effective than the statistical models. Only neural network model, which predict of Daily water supply, is focused on estimation of the operational control. Neural network model takes long learning time and gets into local minimum. This study proposes Neuro Genetic hybrid model which a combination of genetic algorithm and neural network. Hybrid model makes up for neural network's shortcomings. In this study, the amount of supply, the mean temperature and the population of the area supplied with water are use for neural network's learning patterns for prediction. RMSE(Root Mean Square Error) is used for a MOE(Measure Of Effectiveness). The comparison of the two models showed that the predicting capability of Hybrid model is more effective than that of neural network model. The proposed hybrid model is able to predict of Daily water, thus it can apply real time estimation of operational control of water works and water drain pipes. Proposed models include accidental cases such as a suspension of water supply. The maximum error rate between the estimation of the model and the actual measurement was 11.81% and the average error was lower than 1.76%. The model is expected to be a real-time estimation of the operational control of water works and water/drain pipes.

• The Journal of Information Systems
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• v.12 no.2
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• pp.57-72
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• 2003

The purpose of this paper is to propose the modeling of multiagent based SCM and implement the prototype in the Internet environment. SCM process follows the supply chain operations reference (SCOR) model which has been suggested by Supply Chain Counsil. SCOR model has been positioned to become the industry standard for describing and improving operational process in SCM. Five basic processes, plan, source, matte, deliver and return are defined in the SCOR model, through which a company establishes its supply chain competitive objectives. A supply chain is a world wide network of suppliers, factories, warehouses, distribution centers and retailers through which raw materials are acquired, transformed or manufactured and delivered to customers by autonomous or semiautonomous process. With the pressure from the higher standard of customer compliance, a frequent model change, product complexity and globalization, the combination of supply chain process with an advanced infrastructure in terms of multiagent systems have been highly required. Since SCM is fundamentally concerned with coherence among multiple decision makers, a multiagent framework based on explicit communication between constituent agents such as suppliers, manufacturers, and distributors is a natural choice. Multiagent framework is defined to perform different activities within a supply chain. Dynamic and changing functions of supply chain can be dealt with multi-agent by cooperating with other agents. In the areas of inventory management, remote diagnostics, communications with field workers, order fulfillment including tracking and monitoring, stock visibility, real-time shop floor data collection, asset tracking and warehousing, customer-centric supply chain can be applied and implemented utilizing multiagent. In this paper, for the order processing event between the buyer and seller relationship, multiagent were defined corresponding to the SCOR process. A prototype system was developed and implemented on the actual TCP/IP environment for the purchase order processing event. The implementation result assures that multiagent based SCM enhances the speed, visibility, proactiveness and responsiveness of activities in the supply chain.