• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.75-78
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• 2007

The structural methodology in designing a transmission tower have been performed to assume a simple truss behavior. But there're quite differences between a simple truss behavior and a real one. A suitable explanation for a structural stability can be expressed as a semi-rigid connection instead of the assumed hinged connection. This study proposes an alternative structural analysis modelling strategy for the transmission tower design. Proposed element models are truss element model, beam element model, and combined beam-truss element model. The static finite element analysis shows that there's a moment distribution between a mainpost member and the other bracing member.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1997.10a
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• pp.193-196
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• 1997

In this paper we consider a Bayesian theoretic approach to periodic incomplete preventive maintenance with minimal repair at failure. We assume that the system failure rate is increasing as the frequency of PM increases and that the system is replaced at the K-th PM under this maintenance strategy. The optimal policies which minimize the expected cost rates are discussed. We seek the optimal periodic PM interval x and replacement time K under a Weibull failure intensity. Assuming suitable prior distribution for the Weibull parameters, we derive the posterior distribution incorporating failure data and obtain the updated optimal replacement strategies.

• Proceedings of the Korean DIstribution Association Conference
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• 2005.02a
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• pp.327-353
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• 2005

본 연구는 동북아 물류활성화를 위해 지정학적으로 환황해권의 유리한 위치와 우리나라의 경제중심지인 수도권을 배후로 하고 있는 평택항을 중심으로 한 경기지역의 물류네트워크 전략에 대한 연구이다. 본 연구에서는 국내 수출입 컨테이너물동량의 유통채널의 분석과 물류네트워크 방식의 검토 및 사례분석을 통해 경기지역의 특성에 맞는 물류네트워크 방식에 대해 연구하였다. 따라서 하드웨어 개념인 각 거점별 물류시설간의 물류채널인 네트워크 구성방안에 대해 언급하였고 여기서 대권역과 소권역으로 분류하여 2단계 혼합물류네트워크 방식을 소개하였으며, 이러한 각 거점물류시설간의 효율적인 운영을 위해 가장 중요하다고 사료되어지는 물류정보시스템의 구축방안에 대해 언급하였다.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.4
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• pp.760-768
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• 2014

Yet logistics base in China has a refrigerated storage facilities installed areas, the number of those is very limited and is generally insufficient. According to these especial points, a new construction cold chain logistics network design strategy is required from how to use the existing refrigerated warehouses to new issue. For example, however refrigerated storage facility is supplied, can it satisfy all demand of this area? Then does it have optimized location of this area? If future demand expansion, adding that already other refrigerated storage facilities matter? Or, add another refrigerated facilities, optimum cold chain established a network matter? So on. Above problems can be occurred. In order to solve facing many of these issues of distribution network, northeast area in China has been selected as a subject, and we designed a new cold chain distribution network.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.277-280
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• 2002

With significant development of power electronics technology, the proliferation of nonlinear loads such as static power converters has deteriorated power quality in power transmission and distribution systems. Notably, voltage harmonics resulting from current harmonics produced by the nonlinear loads have become a serious problem in many countries. There are already a lot of PV power generation systems installed in building systems whose harmonics are the worst object for distribution systems as a utility interactive system and also it tends to spread out continuously. In this paper, the authors propose a multy-function inverter control strategy which puts a shunt active filter function to the power inverter of the PV power generation system established on a building system. The effectiveness of the proposed system is demonstrated through the simulation of hypothetical power system using PSCAD/EMTDC.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.7
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• pp.966-973
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• 2012

In microgrid demonstration site, distributed generations can make bidirectional power flows on the system. If an accident occurs, the fault current from the inverter based distributed generation is small. However, the conventional protection scheme in distribution network is designed to operate at high fault current. This means that the traditional protection of distribution network is no longer applicable and new protection methods must be developed. In this paper, for two cases, algorithms for protection coordination of demonstration site is proposed and verified through PSCAD/EMTDC simulation. In first case, protection devices are assumed to have the abilities of directional relaying and communication. In second case, protection devices do not have those abilities. Proposed protection coordination algorithms detect the fault locations and protect the microgrid fairly well.

• Management & Information Systems Review
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• v.34 no.3
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• pp.141-160
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• 2015

IoT(Internet of Things) has become a major issue as new type of convergence technology, expending existing of USNs(Ubiquitous Sensor Networks), NFC(Near Field Communication), and M2M(Machine to Machine). The IoT technology defines as a networking for things, which can establish intelligent links collaboratively for sensing networking and processing between each other without human intervention. The purpose of this study is to investigate to forecast the future distribution changes and orientation of contribution of distribution industry on IoT and to provide the implication of distribution changes. To become a global market leader, IoT requires much more development of core technology of IoT for distribution industry, new service creation and try to use a market-based demand side strategy to create markets. So, to become a global leader in distribution industry, this study results show that first of all establishment of standardization of IoT, privacy safeguards, security issues, stability and value were more important than others. The research findings suggest that the development goals of IoT should strive to boost the creation of a global leader in distribution industry and convenience to consider consumers' demands as the most important thing.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1169-1170
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• 2006

Grid connected PV(Photovoltic) generation systems are becoming and actual and general. The power output of PV system is directly affected by the weather conditions. And when AC power supply is needed, power conversion by an inverter and a MPPT control are necessary. The PV power generation system can be treated to a harmonics source for the power distribution system. So, the PV system combined the function of active filter system can be useful applied in power distribution system. AF(Active Filters) intended for harmonic solutions are expending their functions from harmonic compensation of nonlinear loads into harmonic isolation between utilities and consumer. With the test analysis of the proposed control strategy of PV-AF system, the outcome of the test shows the stability and effectiveness of the proposed PV-AF system. The various capability of AF has been proved in previous research and usage. In this paper, authors present a DSP controlled PV-AF system for power conditioning in three-phase industrial or commercial power systems and verify it through experimental results.

• Journal of Distribution Science
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• v.4 no.2
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• pp.65-80
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• 2006

This study is an empirically validation of existing theories into the department store context. This study investigated the effects of perceived quality and customer value(utilitarian value and hedonic value) to customer satisfaction on the basis of previous studies. The data was analyzed by reliability, factor analysis and regression analysis using SPSS program. The results suggest that perceived quality had positive effects on utilitarian value, hedonic value and customer satisfaction, utilitarian value and hedonic value had positive effects on customer satisfaction. These findings also provide implications for the marketing strategy in department store context. However, this empirical study has limitations that can be addressed in the future research.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.11-18
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• 2017

In order to maintain customer voltages within the allowable limit($220{\pm}13V$) as much as possible, tap operation strategy of SVR(Step Voltage Regulator) which is located in primary feeder, is widely used for voltage control in the utilities. However, SVR in nature has operation characteristic of the delay time ranging from 30 to 150 sec, and then the compensation of BESS (Battery Energy Storage System) during the delay time is being required because the customer voltages in distribution system may violate the allowable limit during the delay time of SVR. Furthermore, interconnection of PV(Photovoltaic) system could make a difficultly to keep customer voltage within the allowable limit. Therefore, this paper presents an optimal coordination operation algorithm between BESS and SVR based on a conventional LDC (Line Drop Compensation) method which is decided by stochastic approach. Through the modeling of SVR and BESS using the PSCAD/EMTDC, it is confirmed that customer voltages in distribution system can be maintained within the allowable limit.