• Journal of Electrical Engineering and Technology
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• 제7권4호
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• pp.480-485
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• 2012

Use of photovoltaic (PV) power generation system will become more widespread in the future due to anticipated cost reduction in PV technology. As the capacity of PV systems increases, a variation of power system frequency may prevent the stable output of PV system. However, the standard for the frequency protection of distributed generation in Korea Electric Power Corporation (KEPCO)'s rule does not include the setting of frequency protection. Therefore, this paper analyzes the correlation between the frequency protection requirements and the stability of grid-connected PV system for the adjustable operating setting of frequency protection. The distribution system interconnected with 3 MW PV system is modeled by Matlab/Simulink. The various values of frequency are simulated. For studied cases, the stability of PV system is analyzed. It is concluded that the setting of frequency protection is necessary to consider the stability of PV system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1139_1141
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• 2009

Distributed Generation (DG) is predicted to play a important role in electric power system in the near future. insertion of DG system into existing distribution network has great impact on real-time system operation and planning. It is widely accepted that micro turbine generation (MTG) systems are currently attracting lot of attention to meet customers need in the distributed power generation market In order to investigate the performance of MT generation systems, their efficient modeling is required. This paper presents the modeling and simulation of a MT generation system suitable for grid-connected operation. The system comprises of a permanent magnet synchronous generator driven by a MT. A brief description of the overall system is given, and mathematical models for the MT and permanent magnet synchronous generator are presented. Also, the use of power electronics in conditioning the power output of the generating system is demonstrated. Simulation studies with MATLAB/Simulink have been carried out in grid-connected operation mode of a DG system. The control strategies for grid connected operation mode of DG system is also presented.

• Advances in Traditional Medicine
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• 제7권5호
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• pp.447-458
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• 2008

This paper reviews the historic origin and traits of the classification system used in current Korean herbology textbooks. By reassessing its value, it proposes the most relevant path for future revisions and supplementations. Through an evaluation of the history of the modern style of classification in terms of its efficacy and statistic analysis of the distribution of individual herbs in each category, this paper shows how the classification systems of Korean herbology textbooks were influenced by contemporary Chinese herbology, particularly that of the Cheong [淸] Dynasty. An examination of the academic background, strengths and weaknesses of each classification system demonstrates the need for future research on classification systems to concentrate on resolving the following issues: how well the setting and composition of each classification system reflects reality, and how closely it is connected to related sciences such as etiology and pathogenesis, prescriptionology, and diagnosis.

• 대한한의학원전학회지
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• 제19권1호통권32호
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• pp.155-167
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• 2006

From th Study on A Study on the Thesaurus of Korean medical information for developing search engine, the conclusion is as follow. Knowledge based information system consists of concepts, facts and relation. The final goal of developing the Knowledge based information system is to select, store and control the knowledge and information of Oriental Medicine. Considering limitation of organizing the knowledge system, it is difficult to realize complete basic system and application method. In order to work, it is necessary to combine experts in each part, for example Domain experts, Information and Knowledge engineer. Through the development of knowledge based information system, we can construct EMR(Electronic Medical Record) system in the near future, and it is possible to make semi-expert system. To make Knowledge based information system, we need to establish standards of information that make the distribution of Knowledge and information easily.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
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• pp.453-457
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• 2009

Distributed Generation (DG) is predicted to play a important role in electric power system in the near future. insertion of DG system into existing distribution network has great impact on real-time system operation and planning. It is widely accepted that micro turbine generation (MTG) systems are currently attracting lot of attention to meet customers need in the distributed power generation market. In order to investigate the performance of MT generation systems, their efficient modeling is required. This paper presents the modeling and simulation of a MT generation system suitable for isolated operation. The system comprises of a Permanent magnet synchronous generator driven by a MT. A brief description of the overall system is given, and mathematical models for the MT and permanent magnet synchronous generator are presented. Also, the use of power electronics in conditioning the power output of the generating system is demonstrated. Simulation studies with MATLAB/Simulink have been carried out in islanding operation mode of a DG system.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1340-1347
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• 2017

Utilization of Electric Vehicles (EVs) have been growing popularity in recent years due to increment in fuel price and lack of natural resources. Random unexpected charging by home EV charger in distribution is predicted in the future. The power quality problems such as fluctuation of power factor in a residential distribution network was explored with random EV chargers. This paper proposes a high-performance nonlinear sliding mode controller (SMC) for an EV charging system to compensate voltage distortions and to enhance the power factor against the unbalanced EV chargers. For the verification of the proposed scheme, MATLAB-Simulink simulations are performed on 22.9-kV grid. The results show that the proposed scheme can improve the power factor of a smart grid due to the EV chargers on the grid.

• 조명전기설비학회논문지
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• 제18권2호
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• pp.157-166
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• 2004

최근 중소규모 수용가 수배전반은 일체화, 전자화 및 디지털화로 급격히 발전하고 있다. 본 논문은 중소규모 수용가 수배전반 관리에 필요한 효과적인 정보시각화 기법을 제시하였다. 화재지수, 전력컨디션지수, 수배전반 안전지수, 전력감쇄지수로서 크게 4가지 지수들로 수많은 계측 데이터를 다양한 측면으로 종합적으로 표현해주는 알고리즘을 개발하였다. 정보시각화 수배전반의 디스플레이부를 터치스크린으로 구성하여 사용자 편이성을 강화시켰고, 실시간 데이터를 그래픽적으로 표현하여 유저인터페이스 또한 한층 증대시켰다. 본 논문에서 제시한 정보시각화 기법은 수배전반을 포함한 중전기기의 새로운 발전 방향을 제시할 것으로 사료된다.

• 한국방재학회 논문집
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• 제4권3호
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• pp.83-87
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• 2004

지하공동구내에는 전력, 통신, 가스 냉 난방배관 등 생활에 필요한 공작물이 수용되어 있다. 미래에 지하 공동구의 사용은 확대되며, 화재의 위험이 증가될 것이므로 미연에 화재에 대비해야 하며, 지하공동구내 최대한의 연소방지효과를 가져오게 할 수 있는 소화시스템의 연구가 필요하다. 본 논문은 지하공동구내 화재를 진압하기 위한 노즐의 분무분포를 해석하고, 이에 따라 지하공동구의 화재안전성능을 확보하고자 한다. 앞으로 화재 및 재해예방을 위해 국내기술로서 국내 환경에 맞은 소화시스템 연구가 지속적으로 이루어져야 할 것이다.

• 산경연구논집
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• 제12권10호
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• pp.19-30
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• 2021

Purpose: Dairy marketing cooperatives operate in the agricultural sector of the Ethiopian economy and are supposed to increase the efficiency of the marketing system. This paper aims to study factors affecting the participation of farm households' in dairy marketing cooperatives. Research design, data, and methodology: The research has focused on one primary question. What are the possible factors that affect farm households' participation in dairy marketing cooperatives? The survey questionnaire was developed and an interview was made using enumerators. A total of 1500 sample households were selected randomly using the method of sampling with probability proportionate to size. Descriptive and inferential statistical analysis (binary logit model) was used for analysis. Results: The study result revealed that among thirteen explanatory variables hypothesized to affect dairy producer farmers' participation in dairy marketing cooperatives; eleven were found to be statistically significant. From these findings, it is observed that members of the dairy cooperatives have significant advantage over nonmembers. Conclusions: Both internal and external intervention measures are suggested. Internally, the cooperatives' board of directors should design appropriate strategies to attract nonmembers to improve future participation, and, externally, government, NGOs, and other stakeholders need to emphasize methods that increase nonmembers' participation in dairy marketing cooperatives.

• 한국컴퓨터정보학회논문지
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• 제28권7호
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• pp.29-37
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• 2023

기후변화로 인해 농작물 생산과 유통에 관한 관심이 증대되고 있고, 빅데이터와 AI를 활용한 생산량 예측을 통해 농가의 출하량 조절과 유통단계의 조절에 활용하는 시도가 이루어지고 있다. 농산물 반입량 예측은 가격에 영향을 미칠 뿐 아니라 농가의 출하량과 유통회사의 유통량 조절을 할 수 있으므로 마케팅 전략을 수립하는데 중요한 정보이다. 본 연구에서는 농업 통계 정보 시스템에서 공개한 도매시장 참외 반입량 데이터를 기반으로 미래의 반입량을 예측하는 인공지능 예측 모델을 생성하고 정확도를 평가한다. 우리는 Neural Prophet 기법과 Ensembled Neural Prophet 모델 그리고 GRU 모델 등 세 가지 모델을 사용하여 예측 모델을 생성한다. 모델의 성능은 MAE와 RMSE라는 두 가지 주요 지표를 비교하여 평가한 결과 Ensembled Neural Prophet 모델이 가장 정확하게 예측하였으며, GRU 모델도 앙상블 모델과 유사한 성능을 보여주고 있다. 본 연구에서 개발된 모형은 웹에 publish 되어 현장에서 1년 6개월 동안 사용하고 있으며, 가까운 미래의 참외 생산량을 예측하고, 마케팅 및 유통전략을 수립하는 데 활용되고 있다.