• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.349-357
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• 2002

This research is basically deals with an inventory distribution system with several regional sales branches. Under the continuous review policy, each sales branch places an order to its supplier whenever on hand plus on order inventory falls on the order point, and the order quantity is received after elapsing a certain lead time. This research first shows the method how to apply the product with low lever of demand into the continuous review policy. For the application, we use an order level as the maximum level of inventory during an order cycle. Also we analyze the lost sales case as a customer behavior. Further we use variable demands and variable lead times for more realistic situation. Based on the above circumstances, the research mainly discusses those methods to decide the optimal order level, order point, and order quantity for each sales branch which guarantees the system wide goal level of service, while keeping the minimum level of the system wide total inventory.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1091-1096
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• 2004

It is necessary to consider the stability, economic environmental-friendly problems by the development of the road, supply of the automobile, environmental problem as designing the exhaust system. To reduce the noise and the vibration of the automobile. The need for stricter regulation limits emission and demand for lower fuel comsumption. According to motor vehicle company develop variable type muffler, dual muffler and active intelligence exhaust system unit. Improvement in engine performance and fuel consumption for demand information of pressure fraction and heat characteristics. To be able to determine these factor for we experiment on each case of exhaust system unit. In this study, in order to establish the optimized conditions design factors which are taking many performance as the variable valve, it shows how the standard performance and the additional element of the exhaust system effects on the engine performance.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.3
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• pp.78-84
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• 2002

This research is basically deals with an inventory distribution system with several regional sides branches. Under the continuous review policy, each sales branch places an order to its supplier whenever on hand plus on order inventory falls on the order point, and the order quantity is received after elapsing a certain lead time. This research first shows the method how to apply the product with low lever of demand into the continuous review policy. For the application, we use an order level as the maximum level of inventory during an order cycle. Also we analyze the lost sales case as a customer behavior. Further we use variable demands and variable lead times for more realistic situation. Based on the above circumstances, the research mainly discusses those methods to decide the optimal order level, order point, and order quantity for each sales branch which guarantees the system wide goal level of service, while keeping the minimum level of the system wide total inventory.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.223-226
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• 2004

This paper describers the power demand and the voltage stability in power system. Especially the power demand on summer is more and more increase in korea. According to load quantity is increasing voltage is getting down. And power system becomes unstable. So this paper is prevent voltage down using to ULTC modeling which is a part in a transformer. Therefore our purpose is power system stability increasing as variable state like a load increasing or a fault. Then this paper is using IPLAN and PSS/E as analysis tool. PSS/E is very powerful engine on load flow analysis. And IPLAN is capable of using on variable program compiling with user.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.42
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• pp.21-30
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• 1997

This research fundamentally deals with an analysis of service level for a multi-level inventory distribution system which is consisted of a central distribution center and several branches being supplied stocks from the distribution center, Under continuous review policy, the distribution center places an order for planned order quantity to an outside supplier, and the order quantity is received after a certain lead time. Also, each branch places an order for particular quantity to its distribution center, and receives the order quantity after a lead time. In most practical distribution environment, demands and lead times are generally not fixed or constant, but variable. And these variabilities make the analysis more complicated. Thus, the main objective of this research is to suggest a method to compute the service level at each depot, that is, the distribution center and each branch with variable demands and variable lead times. Further, the model will give an idea to keep the proper level of safety stocks that can attain effective or expected service level for each depot.

• Journal of the Korea Safety Management & Science
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• v.3 no.3
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• pp.65-75
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• 2001

This research fundamentally deals with an analysis of service level for a multi-level inventory distribution system which is consisted of a central distribution center and several branches being supplied stocks from the distribution center, Under continuous review policy, the distribution center places an order for planned order quantity to an outside supplier, and the order quantity is received after a certain lead time. Also, each branch places an order for particular quantity to its distribution center, and receives the order quantity after a lead time. In most practical distribution environment, demands and lead times are generally not fixed or constant, but variable. And these variabilities make the analysis more complicated. Thus, the main objective of this research is to suggest a method to compute the service level at each depot, that is, the distribution center and each branch with variable demands and variable lead times. Further, the model will give an idea to keep the proper level of safety stocks that can attain effective or expected service level for each depot.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.11
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• pp.575-583
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• 2020

Vietnam is the country with the largest animal feed production in Southeast Asia. Domestic animal feed manufacturing enterprises play an important role in animal husbandry in particular and in agriculture in general. However, domestic animal feed enterprises in Vietnam are encountering shortcomings. This paper is conducted to investigate the impact levels of external determinants on business performance of domestic animal feed manufacturing enterprises, including: (i) policy and economic mechanism, (ii) supply-demand of animal feed products, and (iii) nature and level of market competition. We presented a research method, explaining the dependent variable 'business performance' and the independent variables. Data were collected from 120 questionnaires from domestic animal feed manufacturing enterprises. Based on these data, we use Cronbach's Alpha, EFA and run regression model for assessing the impact levels of each independent variable on the dependent variable of business performance of domestic animal feed manufacturing enterprises. The results show that three external determinants including (i) policy and economic mechanism, (ii) supply-demand of animal feed products, and (iii) nature and level of market competition, have positive relationships with business performance. Based on the findings, some recommendations are given for improving business performance of domestic animal feed manufacturing enterprises to ensure sustainability.

• Journal of Advanced Information Technology and Convergence
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• v.10 no.2
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• pp.91-101
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• 2020

Recently, the demand for high penetration of variable renewable energy (VRE) penetration in a power system is increased. In consequence, distribution systems including microgrids confront the increased installation of VRE-based distributed generation. Despite of the high demand of VRE-based distributed generation in a distribution system, the installation of photovoltaic (PV) system in a distribution system has been restricted by various problems. In other words, the hosting capacity for high VRE penetration in a distribution system is limited. This paper analyzes the improvements of hosting capacity VRE penetration of stand-alone microgrid (SAMG) with energy storage system (ESS) by considering virtual-slack (VS) control based on power sensitivity. With the pre-defined power sensitivity, the ESS operates as virtual slack in the SAMG by controlling its bus voltage and phase angle indirectly. Therefore, the ESS enables the increase of VRE penetration in the SAMG. The proposed VS control is realized by analyzing the ESS as a virtual slack in power flow analysis based on power sensitivity. Then its validity is demonstrated with the case study on the SAMG in South Korea with practical data.

• Journal of Energy Engineering
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• v.22 no.4
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• pp.370-375
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• 2013

This paper attempts to estimate the city gas demand function in Korea over the period 1981-2012. As the city gas demand function provides us information on the pattern of consumer's city gas consumption, it can be usefully utilized in predicting the impact of policy variables such as city gas price and forecasting the demand for city gas. We apply lagged dependent variable model and ordinary least square method as a robust approach to estimating the parameters of the city gas demand function. The results show that short-run price and income elasticities of the city gas demand are estimated to be -0.522 and 0.874, respectively. They are statistically significant at the 1% level. The short-run price and income elasticities portray that demand for city gas is price- and income-inelastic. This implies that the city gas is indispensable goods to human-being's life, thus the city gas demand would not be promptly adjusted to responding to price and/or income change. However, long-run price and income elasticities reveal that the demand for city gas is price- and income-elastic in the long-run.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3223-3231
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• 2013

Fire service budget must be increased continually to supply sufficient fire service for safety life of people. A way to increases fire service budget is to plan and improve regional resources facilities tax system. The purpose of this articles is to analyzes the relationship between regional resources facilities tax and fire service budget, fire service investment budget, socioeconomic factor, fire service demand. To do this, this study sets up five hypotheses based on the theoretical backgrounds and the past research. The statistical methods used for the verification of hypotheses are multiple regression analysis and t test. The analysis showed that regional resources facilities tax was positive significant variable for fire service investment budget and fire service budget and socioeconomic factor was a positive significant variable for regional resources facilities tax. And the analysis showed that fire and rescue variable of fire demand factor were positive significant for regional resources facilities tax.