• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.2
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• pp.9-18
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• 1997

Abstract This paper presents a heuristic method for optimal design of water distribution system with multiple sources and potential links. In multiple source pipe network, supply rate at each source node affects the total cost of the system because supply rates are not uniquely determined. The Linear Minimum Cost Flow (LMCF) model may be used to a large scale pipe network with multiple sources to determine supply rate at each source node. In this study the heuristic method based on the LMCF is suggested to determine supply rate at each source node and then to optimize the given layout. The heuristic method in turn perturbs links in the longest path of the network to obtain the supply rates which make the optimal design of the pipe network. Once the best tree network is obtained, the frequency count of reconnecting links by considering link failure is in turn applied to form loop to enhance the reliability of the best tree network. A sample pipe network is employed to test the proposed method. The results show that the proposed method can yield a lower cost design than the LMCF alone and that the proposed method can be efficiently used to design irrigation systems or rural water distribution systems.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.517-531
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• 2021

The water supply facilities of Korea have achieved a rapid growth, along with the other social infrastructures consisting a city, due to the phenomenon of urbanization according to economic development. Meanwhile, the level of water supply service demanded by consumer is also steadily getting higher in keeping with economic growth. However, as an adverse effect of rapid growth, the quantity of aged water supply pipes are increasing rapidly, Bursts caused by pipe aging brought about an enormous economic loss of about 6,161 billion won as of 2019. These problems are not only worsening water supply management, also increasing the regional gap in water supply services. The purpose of this study is to classify hazard evaluation indicators and to rank the water distribution network hazard by cluster using the TOPSIS method. In conclusion, in this study, the entropy-based multi-criteria decision-making methods was applied to rank the hazard management of the water distribution network, and the hazard management ranking for each cluster according to the water supply conditions of the county-level municipalities was determined according to the evaluation indicators of water outage, water leakage, and pipe aging. As such, the hazard ranking method proposed in this study can consider various factors that can impede the tap water supply service in the water distribution network from a macroscopic point of view, and it can be reflected in evaluating the degree of hazard management of the water distribution network from a preventive point of view. Also, it can be utilized in the implementation of the maintenance plan and water distribution network management project considering the equity of water supply service and the stability of service supply.

• Journal of the Korea Safety Management & Science
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• v.17 no.3
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• pp.265-272
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• 2015

The competition between companies for prior occupation of the market is becoming fierce. In this highly competitive situation, it is important for companies to differentiate themselves if they are going to have a chance at success. And the competition to create the best solution method possible is higher than ever. Increased competition is forcing companies to lower costs and improve efficiency. A supply chain management(SCM) has become one of the most important solution methods of competitive advantage. This study has developed a simulator for the supply chain network problem. The simulator is designed to simulate the conditions of an actual supply chain network considering uncertainties. The simulator developed using commercial simulation tool ARENA and the results of computational experiments for a simple example were given and discussed to validate the developed simulator. Further research is needed, but using the simulator could become a useful tool for decision making in the supply chain network area.

• International Commerce and Information Review
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• v.9 no.2
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• pp.257-283
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• 2007

As Global industrial structure is diversified, multinational corporations accomplished fast internationalization to introduction of new management policy by development of an IT technology. Enterprise' business environment is changing transcending border. To overcome raging waves of change accident and to be secured enterprise's future, the logistics is recognized the third profit source joining in curtailment of sale enlargement, production cost. To seek cost saving or reform in logistics class that is last area of pursuit of profits within ancient city life in the fast lane from these viewpoint, importance of study that integrates and manages international logistics bases supply neck walk is emphasized. Specially, to meet on in terms of competitive power security regarding curtailment of logistics cost is available through link between logistics bases, various consumer's request, merchandise and service logistics management that supply fixed quantity as is reliable in right place at good season was embossed by point game plan of business management, and SCM efficiency anger of mortification international logistics activity importance of study that see at that dominate competitive advantage point bring. This study analyzes interrelation and presents model for integration of international logistics bases supply network with supply network habit at factor and supply chain, and supply network activity in integration of supply chain process and production. Also, it establishes following method of study to achieve study purpose for actual proof analysis for integration sequence of international logistics bases supply network. Specially, immersion of network and supply network, very high interrelation appeared by thing which is with international logistics base supply network integration. The integration of international logistics base supply network means that the enterprises which give trust and sincerity deal with market environment change positively and can decide proceeding of various cooperative work. Also, it means the possibility by necessity of cooperative relation and interdependence to continuous immersion and normative immersion, for the maintain of long business relations.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.12
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• pp.602-607
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• 2000

This paper presents the new simulation algorithms using network methods to analysis the steady-state train voltage distribution characteristics in ac auto-transformer fed railroads. In general, the supply system of railroads is composed of non-symmetrical and unbalance transmission line. Therefore, the general method using simplified old algorithms have the self-contradictory errors because the supply line of train railroads is completely unbalanced. In this paper, the simulation results of new developed algorithms is compared with those of EMTP to confirm the effectiveness.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.55-58
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• 2008

This article describes power supply infrastructure construction methods which are considered from U-City infrastructure. For the eisting city and town, it is one the issue to find an economic method to construct outside infrastructure including ubiquitous service device. Because the economic construction method could minimize the construction budget which cost big portion of U-City. And the power supply infrastructure is the fundamental layer to keep network and service layer stable. This paper suggests several ways to construct methods with keeping pre-constructed underground power cable by attaching inepensive power nodal controller working in zigbee network and introduces how to monitor and mana ge the status of power supply to network and service device.

• Journal of Korean Society on Water Environment
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• v.28 no.2
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• pp.202-212
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• 2012

Due to the deterioration of water supply network and the deficiency of raw water, the water utility of local governments have performed various projects to improve their revenue water ratio. However, it is very difficult to estimate the cost for maintaining the revenue water ratio at higher level after completing the project, because local governments have different conditions affecting the operating and maintenance cost of water supply network. The purpose of this study is to present a procedure to estimate the operating and maintenance cost required to maintain the target revenue water ratio of the water supply network. For this purpose, we estimated the cost used only for operation and maintenance of water supply network of 164 local governments with the aid of K-Mean Clustering Analysis and the data from 40 representative local governments. Then, the regression analysis was performed to find relationship between revenue water ratio and the operating and maintenance cost with two different data sets generated by two classification methods; the first method classifies the local governments by means of k-means clustering, and the other classifies the local governments according to the index standardized by the operating and maintenance cost per unit length of water mains per revenue water ratio. The results shows that the method based on the index standardized by the cost and revenue water ratio of each government produces more reliable results for finding regression equations between revenue water ratio and the operating and maintenance cost only for water supply network. The estimated regression equations for each group can be used to estimate the cost required to keep the target revenue water ratio of the local government.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.108-115
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• 2000

This paper presents the new simulation algorithms using network methods to analysis the steady-state train voltage distribution characteristics in ac auto-transformer fed railroads. In general, the supply system of railroads is composed of non-symmetrical and unbalance transmission line. Therefore, the general method using simplified old algorithms have the self-contradictory errors because the supply line of train railroads is completely unbalanced. In this paper, the simulation results of new developed algorithms is compared with those of EMTP to confirm the effectiveness.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.47-55
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• 2019

The army of republic of korea have been continued to transform their logistics support system structure for better efficient logistics support system in preparation for the future environment. Logistics system has supply network structure which is connected by various units and supply network structure received attention as a factor of success of supply network. Many researchers have continuously researched inventory management, transportation or economy factors for supply network, but such a study on the one in military supply network structure analysis is still slower than the study of analysis of other factors until now. In this study, we identify military supply network structure influence factor by application of social network analysis method which is used broadly and analyze co-relationships between supply network structure influence factor and valued APL(average path length) as a criteria of efficiency of military supply network. By this study it has value of military supply network influence factor identification for the better military supply network fabrication.

• Journal of Korean Society for Quality Management
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• v.47 no.2
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• pp.381-395
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• 2019

Purpose: This study aims to conduct a systematic literature review to suitably identify wide and specific issues and topics on service quality in supply chain. Methods: This study is to investigate service quality in supply chain research using a systematic literature review methodology. In order to extract influential journals and papers, we used the SJR impact factor provided by the SCOPUS database. The collected 169 papers were analyzed using bibliometric analysis, citation analysis as well as keywords network. Results: We conducted a bibliometric analysis to identify top authors contributing to service quality in supply chain and their issues, and further examined important keywords and new emerging keywords. In addition, we extracted five influential papers by PageRank to clarify critical issues and divided into five clusters to identify topics of service quality in supply chain by using network-based approach. In order to examine comprehensive issues and topics of service quality in supply chain, we constructed a keyword network to observe difference in the classification of important keywords across network centrality measures. Conclusion: Our study reviewed literature on service quality in supply chain and explored the future directions and trends of service quality in supply chain.