• Journal of Electrical Engineering and Technology
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• 제6권1호
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• pp.25-31
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• 2011

The purpose of power system maintenance is to prevent equipment failure. The maintenance strategy should be designed to balance costs and benefits because frequent maintenance increases cost while infrequent maintenance can also be costly due to electricity outages. This paper proposes maintenance modeling of a power distribution system using reliability centered maintenance (RCM). The proposed method includes comprehensive equipment modeling and impact analysis to evaluate the effect of equipment faults. The problem of finding the optimum maintenance strategy is formulated in terms of dynamic programming. The applied power system is based on the RBTS Bus 2 model, and the results demonstrate the potential for designing a maintenance strategy using the proposed model.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.93-96
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• 2006

PEMFC(proton exchange membrane fuel cell) is most applicable to automobile in various types of fuel cell. However, to improve system dynamics and logn term Performance fuel cell is supported by auxiliary power unit forming hybrid system. The operating strategy of hybrid system influences on efficiency and stability. In this paper the proper strategies are compared each other considering power distribution and stable system operation. The chosen strategy is simulated by MATLAB simulink to forecast realization of fuel cell hybrid vehicle

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.127-127
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• 2010

This study describes the optimal design of shield to improve the insulation performance of vacuum interrupter(VI). Axi-symmetric finite element routine including floating boundary condition for shields was applied to analyze electric potential and field distribution in VI. A ($\mu-\lambda$) Evolution Strategy(ES) is employed as optimization method. Three design variables of shield are selected for minimizing the maximum electric field strength in VI. Finally, optimal solution for shield is obtained and compared with the result of the prototype.

• 한국멀티미디어학회논문지
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• 제17권4호
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• pp.458-465
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• 2014

In this paper, we propose a strategy to distribute the energy consumption over the network. The proposed strategy is based on geographic routing. We use a smart base station that maintains the residual energy and location information of sensor nodes and selects a head node and an anchor node using this information. A head node gathers and aggregates data from the sensor nodes in a target region that interests the user. An anchor node then transmits the data that was forwarded from the head node back to the smart base station. The smart base station extends network lifetime by selecting an optimal head node and an optimal anchor node. We simulate the proposed protocol and compare it with the LEACH protocol in terms of energy consumption, the number of dead nodes, and a distribution map of dead node locations.

• 한국컴퓨터정보학회논문지
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• 제24권1호
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• pp.167-178
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• 2019

In this paper, we study the multi-objectives vehicle and drone routing problem with time windows, MOVDRPTW for short, which is defined in an urban delivery network. We consider the dual modal delivery system consisting of drones and vehicles. Drones are used as a complement to the vehicle and operate in a point to point manner between the depot and the customer. Customers make various requests. They prefer to receive delivery services within the predetermined time range and some customers require fast delivery. The purpose of this paper is to investigate the effectiveness of the delivery strategy of using drones and vehicles together with a multi-objective measures. As experiment datasets, we use the instances generated based on actual courier delivery data. We propose a hybrid multi-objective evolutionary algorithm for solving MOVDRPTW. Our results confirm that the vehicle-drone mixed strategy has 30% cost advantage over vehicle only strategy.

• The Journal of Asian Finance, Economics and Business
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• 제8권7호
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• pp.525-532
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• 2021

This study examines the association between a firm's business strategy and audit report lags. This study employs 5,072 firm-year observations from 2015 to 2019. Our sample comprises all of the firms listed on the Korea Composite Stock Price Index (KOSPI) market and Korea Securities Dealers Automated Quotation (KOSDAQ). We perform OLS regression analysis to test our hypothesis. The OLS regression analysis was conducted through the SAS and STATA programs. We find that business strategy is positively associated with audit report lags. Especially, we find that defender firms are negatively associated with audit report lags. The findings of this study suggest that prospector-like firms would increase their performance uncertainty as well as audit risk. Therefore, prospector-like firms interfere with the efficient audit procedures of auditors. On the other hand, our findings indicate that defender-like firms would decrease their performance uncertainty as well as an audit risk because they focus on simple product lines and cost-efficiency. For this reason, auditors will be able to carry out the audit procedures much more easily. Our results present that a prospector-like business strategy degrades audit effectiveness as it exacerbates a company's financial risk, willingness to accept uncertainty, and the complexity of organizational structure.

• Journal of Forest and Environmental Science
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• 제37권1호
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• pp.14-24
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• 2021

A plant community is a group of populations that coexist in space and interact directly or indirectly with the environment. In this paper, we determined the pattern of tree species composition in response to soil variables in Khadimnagar National Park (KNP), which is one of the least studied tropical forests in Bangladesh. Soil and vegetation data were collected from 71 sample plots. Canonical Correspondence Analysis (CCA) with associated Monte Carlo permutation tests (499 permutations) was carried out to determine the most significant soil variable and to explore the relationship between tree species distribution and soil variables. Soil pH and clay content (pH with p<0.01 and Clay content with p<0.05) were the most significant variables that influence the overall tree species distribution in KNP. Soil pH is related to the distribution and abundance of Syzygium grande and Magnolia champaca, which were mostly found and dominant species in KNP. Some species were correlated with clay content such as Artocarpus chaplasha and Cassia siamea. These observations suggest that both the physico-chemical properties of soil play a major role in shaping the tree distribution in KNP. Hence, these soil properties should take into account for any tree conservation strategy in this forest.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.1213-1216
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• 1998

This paper presents the result of a feasibility study for the prediction method of fault symptoms on 22.9kV distribution line. In this paper, real distribution data was collected and analyzed to isolate failure signatures or parameters which were distinct behaviors before and after failure incident. A new strategy of analysis-based (event-date concept) prediction algorithm for the distribution insulators and a developed model system were also discussed.

• 유통과학연구
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• 제21권6호
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• pp.13-20
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• 2023

Purpose: This research explores the development of music business distribution channels to attract potential customers based on the current and prior literature. As a result, the research will provide solutions for practitioners in the music distribution channel how they create effective channel in new industry phase which has experienced significant changes due to technological advancement and consumer behavior. Research design, data, and methodology: To obtain textual data in the literature storage, the author conducted content analysis. Even though there are numerous textual resources, selecting only high-quality text data that is only peer-reviewed journal articles and books consistently indicate a high degree of reliability and validity to keep the advantage form content analysis approach. Results: The present study figured out that there are five strategies to attract potential consumers in the music distribution channel, such as (1) 'Marketing Mix', (2) 'Streaming Platforms and Online Music Stores', (3) 'Brick and Mortar Stores and Concerts, and Events', (4) 'Platforms Exclusives and Limited-Edition Merchandise', and 'Partnerships and collaborations. Conclusions: In sum, the practitioners need to consider include building relationships with the fans, studying and understanding their target market, utilizing multiple available distribution channels, embracing new technologies, and analyzing the effectiveness of the adopted distribution channels.

• 유통과학연구
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• 제4권2호
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• pp.145-165
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• 2006

중국의 자동차시장은 급속한 경제성장에 맞물려 자동차 수요가 2010년에는 국내시장 대비 2.4배 이상의 규모인 570만대, 세계 3위의 자동차시장 규모에 이를 것으로 예상 되고 있다. 또한 점차 사회 및 투자인프라의 안정화가 이루어지고 있어 세계의 글로벌 기업들에게 있어서 중국자동차 시장은 부(富) 창출의 시장이며 기회의 땅으로 인식되고 있다. 이와 반면, 중국은 전 세계의 자동차 기업들이 이미 진출해 있는 세계 자동차기업의 각축장이라는 위협의 시장이기하다. 2002년 3월 동풍과 열달 자동차와의 3자 합작투자를 수행함으로써 중국시장 진입이 현실화가 된 기아자동차로서 직면한 과제는 무엇보다 중국시장을 어떻게 침투할 것인가의 문제였다. 특히 중국의 자동차 채널환경은 한국과는 크게 달라 이러한 문제는 더욱 어려움을 증폭하기 충분했다. 본 사례는 2006년 4월 20일부터 4월 22일의 기간 동안 기아자동차의 중국 염성 공장 및 대표사무소가 있는 상해를 방문하여 인터뷰를 통해 수집한 자료를 기초로 2002년 3월 기아자동차가 중국 자동차 산업에 첫 발을 내딛을 무렵 그들에게 직면한 유통채널 환경과 그들이 유통채널의 어려움을 해결하기까지 그 과정에 대해 면밀히 살펴본다.