• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.26-31
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• 2011

In this paper, we focused on the loop distribution system to solve the international issues of energy depletion and global warming. The conventional method of reconfiguration of distribution system was moving open points of switches from an actual switch position to another, while an appropriate switch must be opened to preserve the radial structure and this procedure is continued til there is no further loss reduction. However, the loop distribution system is the best optimization method to minimize loss than the other methods which is preserving radial structure. So we analyzed 3 types of loop distribution system upgraded from radial distribution system by changing normally open switch to normally closed switch. The simple 3 types of model system for simulation were composed, and each types of loop system were simulated in accordance with varying parameters. As a result of simulations, the loss reduction was different for each types of loop distribution system and each loop types have constraints for composing loop distribution system. The algorithms propose the method how to construct loop distribution system regarding constraints. Type I that needs least requirements get least loss reduction and Type III that needs most requirements get maximum loss reduction. On the other hand, Type I was most feasible distribution system to be realized.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.1
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• pp.6-12
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• 2020

In recent years, the demand for the distribution of energy resource has been increasing. However, the output power is limited by the stability of the distribution network. This study proposes an active distribution network that can reconfigure the distribution line using an active phase controller. The conventional distribution network has a fixed structure, whereas the proposed active distribution network has a variable structure. Therefore, the active distribution network can increase the output power of the distribution energy resource and reduce the overload of distribution line facilities. The active phase controller has two operation modes to minimize the circulating current during dynamic reconfiguration. In this study, the voltage and current control algorithms are proposed for the active phase controller. The proposed method for the active phase controller is simulated via PSIM simulation.

• Journal of the Korean housing association
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• v.7 no.1
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• pp.95-103
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• 1996

The purpose of this research are to analyze the Chinese-Korean dwelling spatial structure and distribution of its area as a part of research for Chinese-Korean dwelling and village in China. The study area for this research was chosen three Chinese provinces located in north east part of China where the population of Chinese-Korean dwelling spatical structures and distribution of their area were found using this research.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.1
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• pp.214-221
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• 2003

In this study, based on the effect of the interaction of fracture mechanics by graphite and fatigue limit phenomena of the microscopic observation various matrix structure, spheroidal ratio, size of graphite and distribution etc. parameters containd with Ductile Cast Iron. Therefore, in this study, different ferrite-pearlite matrix structure and spheroidal ratio of graphite of 70%, 80% and 90%, GCD40, GCD45-1 and GCD45-2 series and three different ferrite-pearlite matrix structure, GCD 45-3, GCD 50, GCD 60 series, all of which contain more than 90% spheroidal ratio of graphite, were used to obtain the correlation between mean size of spheroidal graphite and fatigue strength. (1) 73% pearlite structure had the highest fatigue limitation while 36% pearlite structure had the lowest fatigue limitation among ferrite-pearlite matrix. the increase in spheroidal ratio with increasing fatigue limitation, 90% had the highest, 14.3% increasing more then 10%, distribution range of fatigue life was small in same stress level. (2) (equation omitted) of graphite can be used to predict fatigue limit of Ductile Cast Iron. The Statistical distribution of extreme values of (equation omitted) may be used as a guideline for the control of inclusion size in the steelmaking processes.

• The Journal of Information Systems
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• v.15 no.2
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• pp.173-193
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• 2006

This study first conceptualizes and investigates five dimensions of SCM activities, such as organizational capacity, revitalization support collaboration, appraisal and responsibility, and information system activities. Second, this study develops three dimensions of a supply chain structure, and proposes a balanced scorecard (BSC) model in order to measure business performance. And then, this study establishes too research hypotheses as follows: H1. The SCM activities varies with the supply chain structure. H2. The management performance varies with the supply chain structure. In the questionnaire survey for empirical analysis, this study carefully selected 809 of companies in Korea. We conducted a survey by mail and collected 127 data. Out of 127 data we actually used 103 responses for statistical analysis. After conducting statistical analysis, we could find the results as followed: 1) The supply chain structure was classified into three networks through a clustering procedure, such as supply network, conversion network, and distribution network, and these networks were used to testify hypotheses. As a result the effect of SCM activities varies according to three networks and especially, the companies in distribution network were more active than those in supply and conversion networks doing SCM activities. 2) We may conclude that business performance varies with three networks, and distribution network achieves better performance than supply and conversion networks do.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.1
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• pp.6-11
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• 2013

In this paper, the temperature characteristics of mold transformer for the distribution power system have been analyzed by using computational fluid dynamics(CFD). The model has been modeled by coil, cores, insulating materials and frames about 3MVA grade mold transformer and analyzed the temperature distribution of the structure with a heat fluid. The fluid, which is incompressible ideal gas, is analyzed as a turbulent flow phenomenon on the assumption that it is natural cooling of transformer cooling system. Through this study, by examining the temperature distribution and hot-spot of the structure field of the mold transformer, cooling design and temperature distribution information, which are demanded for designing are estimated.

• Steel and Composite Structures
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• v.25 no.4
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• pp.473-484
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• 2017

In this study a seismic retrofit scheme for a building structure was presented using steel plate slit dampers. The energy dissipation capacity of the slit damper used in the retrofit was verified by cyclic loading test. Genetic algorithm was applied to find out the optimum locations of the slit dampers satisfying the target displacement. The seismic retrofit of the model structure using the slit dampers was compared with the retrofit with enlarging shear walls. A simple damper distribution method was proposed using the capacity spectrum method along with the damper distribution pattern proportional to the inter-story drifts. The validity of the simple story-wise damper distribution procedure was verified by comparing the results of genetic algorithm. It was observed that the capacity-spectrum method combined with the simple damper distribution pattern leaded to satisfactory story-wise distribution of dampers compatible with the optimum solution obtained from genetic algorithm.

• Journal of Distribution Science
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• v.13 no.6
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• pp.17-23
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• 2015

Purpose - Transnational corporations (TNCs) have influenced drastic changes (financial services, manufacturing, labor, technology transfer) in Central Eastern Europe (CEE). This paper examines the indirect changes in the CEE pattern of industrial development and market distribution. Research design, data, and methodology - Over 25 years, neighboring (or rival) countries competed to attract TNCs as a double-edged strategy for privatization and debt reduction. Through their experience attracting foreign direct investment (FDI), many countries started to reflect aspects of national capitalism. Countries also began to realize in 2010 that TNCs sought to enter markets with more favorable conditions for export-oriented manufacturing. Results - The analysis reveals that TNC investment strategies were aimed at eliminating local competition to acquire industrial "brown fields" to convert into "green fields." CEE countries have since strengthened their national systems and the support of large-scale state-owned enterprises and small and medium-sized start-up enterprises. Conclusions - CEE has changed based on industrial development and a regional structure of TNC market distribution and associated government policies. The pattern toward flexible markets gives countries the ability to further their economies.

• Journal of Korea Society of Industrial Information Systems
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• v.10 no.4
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• pp.110-119
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• 2005

This study develops three dimensions of a supply chain structure (i.e., supply network, conversion network, distribution network) and proposes a balanced scorecard (BSC) model in order to measure management performance. We may conclude that management performance depends on the supply chain structure, and performance of distribution network is better than that of supply and conversion networks based on the result of Scheff multi-comparison.

• Journal of Distribution Science
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• v.18 no.3
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• pp.25-36
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• 2020

Purpose: Based on previous researches on social factors of digital item purchase in digital contents distribution platforms such as SNS, we aim to develop the integrated model that accounts for the dynamic and interactive relationship between social structure indicators and digital item purchase. Research design, data and methodology: A PVAR model was used to capture endogenous and dynamic relationships between digital item purchase and network indicators. Results: We find that there exist considerable endogenous and dynamic relationships between digital item purchase and network structure variables. Not only lagged in-degree and out-degree but also in-closeness and out-closeness centrality have significant and positive impacts on digital item purchase. Lagged clustering has a significant and negative effect on digital item purchase. Lagged purchase has a significant and positive impact just on the present in-closeness and out-closeness centrality; but there is no significant effect of lagged purchase on the other two degree variables and clustering coefficient. We also find that both closeness centralities have much higher carryover effect on digital item purchase and that the elasticity of both closeness centralities on the purchase of digital items is even higher than that of other network structure variables. Conclusions: In-closeness and out-closeness are the most influential factors among social structure variables of this study on digital item purchase.