• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
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• pp.105-110
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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.

• 조명전기설비학회논문지
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• 제23권12호
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• pp.210-216
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• 2009

마이크로그리드는 전력시스템의 계획 및 실시간 운영에 있어서 매우 큰 영향을 미치며 중요한 역할을 할 것으로 판단된다. 따라서 본 연구에서는 빌딩의 마이크로그이드의 중요한 마이크로소오스인 마이크로터빈 발전시스템의 Matlab/Simulink 모델과 전압-주파수제어기를 개발하였다. 또한 부하에 독립적으로 전원을 공급하기 위한 전력시스템을 구성, 모의를 통하여 MTG시스템의 특성을 분석하였다.

• 한국콘텐츠학회논문지
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• 제20권6호
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• pp.460-469
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• 2020

본 연구는 코로나19 사태로 인하여 최근 이슈로 떠오르는 '마스크 5부제'에 대한 온라인 뉴스 기사와 카페글을 분석하여 언론과 대중들의 반응을 담고 있는 매스 미디어와 소셜 미디어 의제를 파악하고, 그 차이점을 알아보았다. 분석을 위해 네이버 뉴스 기사 전문 2,096건과 카페글 1,840건을 수집하고 데이터 전처리 과정과 정제과정을 거쳐 단어 빈도분석, 워드 클라우드, LDA 토픽모델링 분석을 실시하였다. 분석 결과, 매스 미디어에 비해 소셜 미디어는 '대리 구매', '개학 연기', '마스크 사용', '마스크 구입'과 같이 실생활 관련 토픽이 나타나 개인 미디어의 특성이 반영되어 정보 전달의 기능 보다는 개인의 의견, 감정, 정보를 교류하는 역할을 하는 것으로 나타났다. 본 연구에 적용된 연구방법의 적용으로 다양한 미디어 분석을 통해 사회이슈가 공중의제화되고, 정부의제로 진화하는 정책의제설정 과정에서 참고자료로 활용될 수 있을 것이다.

• Journal of Periodontal and Implant Science
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• 제46권2호
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• pp.96-106
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• 2016

Purpose: Stress distribution and mandible distortion during lateral movements are known to be closely linked to bruxism, dental implant placement, and temporomandibular joint disorder. The present study was performed to determine stress distribution and distortion patterns of the mandible during lateral movements in Class I, II, and III relationships. Methods: Five Korean volunteers (one normal, two Class II, and two Class III occlusion cases) were selected. Finite element (FE) modeling was performed using information from cone-beam computed tomographic (CBCT) scans of the subjects' skulls, scanned images of dental casts, and incisor movement captured by an optical motion-capture system. Results: In the Class I and II cases, maximum stress load occurred at the condyle of the balancing side, but, in the Class III cases, the maximum stress was loaded on the condyle of the working side. Maximum distortion was observed on the menton at the midline in every case, regardless of loading force. The distortion was greatest in Class III cases and smallest in Class II cases. Conclusions: The stress distribution along and accompanying distortion of a mandible seems to be affected by the anteroposterior position of the mandible. Additionally, 3-D modeling of the craniofacial skeleton using CBCT and an optical laser scanner and reproduction of mandibular movement by way of the optical motion-capture technique used in this study are reliable techniques for investigating the masticatory system.

• 경영정보학연구
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• 제4권2호
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• pp.209-222
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• 2002

EDI(Electronic Data Interchange)는 빠른 정보 제공, 문서 작업 감소, 원활한 정보교환, 고객 서비스 향상 등의 장점을 지니고 있어 수년간 기업 활동을 지원하는 수단으로 널리 활용되어 왔다. 하지만 최근 인터넷을 통해 e-비즈니스 환경이 구현됨에 따라 EDI는 e-비즈니스를 수행하는 문서양식과 서식, 문서내용, 비즈니스 프로세스, 문서 처리방법 및 표현방법 등을 포함하는 정보활동의 총체적 개념인 ebXML(electronic business eXtensibleMarkup Language) 프레임워크(Framework)로 변화해 가고 있다. 이러한 ebXML 프레임워크를 산업에 적용하기 위해서는 비즈니스 프로세스(BP)나 핵심 컴포넌트(CC), 협력규약 프로필(CPP), 협력규약 합의(CPA)를 등록하는 등록저장소, 메세징 시스템 등이 필요하다. 본 연구에서는 타 산업에 비해 상대적으로 EDI를 많이 사용하고 있는 항만물류산업을 대상으로 EDI 시스템의 현황 및 문제점과 업무 프로세스를 분석하였다. 업무 프로세스 분석을 통해 ebXML프레임워크의 핵심요소인 등록저장소에 등록될 비즈니스 프로세스를 UN/CEFACT 모델링 방법론(UN/CEFACT Modeling Methodology)을 사용하여 정의하고 모델링 하였다. 본 연구에서는 ebXML 프레임워크를 항만물류산업에 적용하기 위해 UN/CEFACT 모델링 방법론에 따라 협업(Business Collaborations), 트랜잭션(Business Transactions), 문서흐름(Business Document Flows), 구성법(Choreography), 패턴(Pattem) 등을 UML(Unified Modeling Lanfuage)로 표현하였으며, 본 연구결과를 통하여 ebXML 프레임워크를 타 산업에 적용할 수 있는 메타방안을 제시하고 있으며, 항만물류산업에 속한 개별기업에서 실제 시스템을 구현할 수 있는 비즈니스 프로세스 설계를 목적으로 하고 있다.

• Journal of Information Technology Applications and Management
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• 제18권4호
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• pp.81-93
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• 2011

By using GOSST theory, this paper models SSCFLP taking FLP, capacity of the facilities, single source capacitated limitation level and service enhancement issues into consideration. GOSST theory is strongly suggested as the solution procedure for these issues. We have used clustering of Center of Gravity method using the case study of the company S and then, took a heuristic GOSST measure in the alternative selection process. As a result, the research finds an alternative solution that both meets the satisfactory level of service and achieves consistent distribution capacity. When using this modeling, especially, to select the location of the logistics distribution center, the efficiency of current facilities is maximized while offering the minimum geometric distance for the alternative. Also, we can expect that the illustrated model and alternative solution can be applied to architecture of distribution system, to selection of telecommunication system locations for wireless network and to relocation of related facilities due to their sensitivities to location and weight.

• 대한기계학회논문집B
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• 제25권12호
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• pp.1784-1792
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• 2001

Numerical analysis on a parallel flow heat exchanger(PFHE) is performed using 2 dimensional turbulent porous modeling. This modeling can consider three-dimensional configuration of passage (flat tube with micro-channels), and the stability and accuracy of numerical results are improved. The geometrical parameters(e.g., the position of separators, inlet/outlet, and porosity of passages of a PFHE) are varied in order to examine the flow and thermal characteristics and flow distribution of the single phase multiple passages system. The flow non-uniformities along the paths of the PFHE are observed to evaluate the thermal performance of the heat exchanger. The location of inlet affects the heat transfer, and the location of outlet affects the pressure drop. The porosity with the optimum thermal performance is around 0.53.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1629-1633
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• 2004

In this paper, we first implement the simulation environment to investigate the efficient control method of a Fuel Cell Electric Vehicle (FCEV) system with battery. The subsystems of a FCEV including the fuel cell system, the electric motor (including the power electronics) and the tansmission (reduction gear), and the auxiliary power source (battery) are mathematically fomulated and coded using the Matlab/Simulink software. Some examples are given to show the capabilities of the modeled system and d a basic control strategy is examined for the economic energy distribution between the fuel cell and the auxiliary power source. It is illustrated by simulations that the actual vehicle velocity follows the given desired velocity pattern while both SOC control and power distribution control are being performed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.298-299
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• 2011

The impacts of EV charging demands on power system such as increased peak demands may be developed by means of modeling a stochastic distribution of charging and a demand dispatch calculation. Optimization processes are proposed to determine optimal demand distribution portions so that charging costs and demands can be managed optimally. There are two optimization methods which have different effects on the outcome. These focus either on the Electric vehicle customer side (cost optimization) or the System Operator side (Load-weighted optimization).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.113-115
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• 2000

This paper presents the modeling and simulation studies, using PSCAD/EMTDC, for the operation of DR(Distributed Resources) connected to the power system. In this study, we model the DR operated in parallel with the distribution system and simulate several operation modes of DR. Finally, the transient characteristics of the operation modes are evaluated with IEEE Standard 519-1992. IEEE Recommended Practice and Requirements for Harmonic Control in Electric Power Systems