• Journal of Advanced Marine Engineering and Technology
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• 제29권5호
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• pp.579-586
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• 2005

Recently, it has demanded to the wireless monitoring system in stand-alone PV power generation system. We propose the multiplex monitoring method using RF unit of low-price. RF unit consists of RF modem and communication controller. It is also able to use by repeater to communicate long distance. In this paper. two algorithms were programmed by CCS-C and C++ for multiplex monitoring method, The algorithm of choosing unit was used 'select and poll method' and the course assignment algorithm was embodied with 'Bellman-Ford algorithm'. The good result was achieved in the actual test without communication-data lose. The proposed method will be applied such as monitoring system of PV light on the wayside, monitoring system of unmanned lighthouse, monitoring system of refrigeration container on vessel and so on. It can be applied in the field that various ocean energy system.

• 한국정보처리학회논문지
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• 제2권1호
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• pp.119-129
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• 1995

본 논문에서는 분산 실시간 프로그램의 스케줄가능성 분석 방법을 제안한다. 스케 줄가능성 분석을 위한 여러 가지 방법이 개발되었지만, 이 방법들은 가능한 모든 상 태공간을 추적하거나 고정 우선순위 스케줄 방법을 사용했기 때문에 지수적인 시간 과 공간의 복잡성을 야기한다. 따라서 상태 공간을 줄여서 더 이른 시간단위에서 스케 줄가능성을 조사하는 방법이 필요하다. 본 논문에서 제시한 스케줄가능성 분석 방법은 번역시간에 결정될 수 있는 프로세스들의 최대 수행시간, 주기, 마감시간, 동기화 시 간을 고려하여 동기화 동작 이후에 남는 계산시간과 마감시간의 차이를 계산하여 실시 간 프로세스가 마감시간을 지키는가를 판단하는 새로운 알고리즘을 제안하고, 실험을 통하여 그 성능을 평가한다. 실험에 의하여 Fredette의 방법과 비교하면 약 50퍼센트 정도 더 이른 단위시간에 스케줄이 불가능함을 판단할 수 있다.

• 한국정보처리학회논문지
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• 제2권3호
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• pp.277-287
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• 1995

멀티미디어 통신 단말기를 이용하여 다자간 영상회의를 구현하기 위하여 단말기들 은 논리적으로 상호 연결되어 있어야 하며, 단말기 사이의 연결을 구현하는 방법에는 중앙 집중식 방식과 분산식 방식이 있다. 이중 집중식 영상회의의 구현을 위하여 다 지점 제어 장치가 필요하며, 이러한 다지점 제어장치를 설계하기 위한 방법에는 음성 및 영상처리 장치의 개발 방법에 따라 디지탈에 의한 방식과 아날로그에 의한 방식으 로 크게 나눌 수 있다. 이러한 다지점 제어장치의 의미 및 개발방법을 살펴보기 위하 여, 본 논문에서는 다지점 제어 장치에 대한 주요기능을 정리하였으며, 다지점 제어장 치의 구현을 위한 여러 방법들을 제시하였다.

• 전산구조공학
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• 제4권1호
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• pp.83-94
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• 1991

본 연구에서는 이상화구조요소법을 적용하여 골조구조물의 비선형해석을 높은정도로서 짧은 계산시간에 수행할 수 있는 해석이론과 컴퓨터프로그램을 개발하였다. 이를 위해 골조구조물을 구성하는 보-기둥(Beam-Column)부재에 대한 이상화구조요소를 부재에 존재하는 초기결함의 영향도 고려하여 정식화한다. 요소의 접선탄성강성행렬은 에너지원리를 적용하여 명시적인 형태로 도출하며, 최종강도조건은 요소에 소성붕괴메카니즘이 형성될때를 기준으로 정식화한다. 또한, 요소의 최종강도후 강성행렬도 근사적인 방법을 이용하여 명시적인 형태로 도출한다. 본해석법의 정도와 유용성은 단위부재 및 골조구조모형에 대한 기존의 실험 및 수치해석결과등과 비교하여 확인한다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.617-619
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• 2021

만주 문자는 세로로 씌여지며 한 단어 안에서는 띄어쓰기 없이 이어져 있기 때문에 문자를 인식하기 전에 글자영역 분리와 글자를 이루는 단위를 분리해 내는 전처리과정이 필요하다. 본 논문에서는 글자영역을 추출하고 글자의 단위를 끊어내는 전처리 방법을 기술한다. 기존 연구가 단어별 또는 문자단위로 인식하는 방법을 전제로 하거나, 이어져 있는 글자의 줄기를 없앤 후 남는 부분으로 인식하는 것과 달리, 본 방법은 인식 가능한 단위별로 글자를 끊어낸 다음 그 단위의 합성으로 글자를 인식하는 방법에 적용할 수 있다. 실험을 통하여 본 방법의 유효성을 검증하였다.

• 한국환경복원기술학회지
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• 제10권1호
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• pp.23-35
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• 2007

Nowadays, as a result of increasing income and spare time, the social demands for better living environment become more increasing. Above all, landscape improvement, the essential part of physical environment, will be a more important subject in urban planning. In these circumstances, classification of urban scenic quality is required for urban landscape development programs. The major purpose of this study is to suggest a technical method of designing urban scenic quality map for urban district area based on the scenery management system of the USDA forest service and literature studies. As a conclusion of this study, four steps are desirable for the technical method for designing a scenic quality map of urban districts areas : 1) Define a landscape unit on the map, 2) Take a photograph of these landscape unit on site, 3) Evaluate the landscape unit by semantic differential scale with landscape adjectives, and 4) Draw the scenic quality map, investigate the landscape characteristics and suggest the landscape scenic development plans.

• 한국지구과학회지
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• 제24권5호
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• pp.371-377
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• 2003

The purpose of this study is to examine the effects of utilizing concept maps in a rock-related unit. To do this, two groups composed of 73 sixth grade students engaged in this study. One group (experimental group) participated in utilizing concept maps in the unit, the other (control group) took part in traditional instruction in the same unit. The results of this study are as follows, after seventeen sessions: First, the achievement between the two groups showed significant difference. It indicates that utilizing concept maps as an instructional method is effective. Second, in the examination of the experimental group's attitudes toward concept maps, the students showed more affirmative responses on cognitive items than on affective items. Third, the students showed that they have difficulty in the method and the procedure of drawing up the concept maps. It indicates that the method and the procedure are sufficiently learned before instruction begins.

• Journal of Power Electronics
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• 제16권2호
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• pp.666-674
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• 2016

In this paper, a high efficiency satellite electrical power supply system is proposed. The increased efficiency of the power supply system allows for downscaling of the solar array and battery weight, which are among the most important satellite design considerations. The satellite power supply system comprises two units, namely a generation unit and a storage unit. To increase the efficiency of the solar array, a maximum power point tracker (MPPT) is used in the power generation unit. In order to improve the MPPT performance, a novel algorithm is proposed on the basis of the hill climbing method. This method can track the main peak of the array power curve in satellites with long duration missions under unpredicted circumstances such as a part of the array being damaged or the presence of a shadow. A lithium-ion battery is utilized in the storage unit. An algorithm for calculating the optimal rate of battery charging is proposed where the battery is charged with the maximum possible efficiency considering the situation of the satellite. The proposed system is designed and manufactured. In addition, it is compared to the conventional power supply systems in similar satellites. Results show a 12% increase in the overall efficiency of the power supply system when compared to the conventional method.

• KIEAE Journal
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• 제12권1호
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• pp.83-90
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• 2012

Over the world, social demands and concerns of energy and resource depletions and environmental conservation have resulted in many researches and applications on sustainable development and construction. In order to support these demands and concerns, international green building certification systems such as LEED(Leadership in Energy and Environmental Design) and BREEAM(Building Research Establishment Environmental Assessment Method) were developed. In Korea, the green building certification system was introduced in 2000 and widely applied to all types of new buildings in order to induce the diffusion of sustainable buildings on May, 2010. This paper investigates the importance of assessment criteria on multi-unit apartment projects among certification rating systems using the AHP(Analytic Hierarchy Process) method and suggests a new direction on certification assessment standards. For applying the AHP method, the survey of staffs in green building certification consulting companies and architectural design companies was conducted via e-mail. As a result, criteria like energy, indoor environment, land use, pollution control, and ecological environment among 9 main ones turned out important on assessing green building certification at multi-unit apartment projects, while criteria like water resource, transportation, maintenance management, and material and resource did relatively unimportant.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제25권4호
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• pp.196-220
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• 2021

This study formulates a new geometric parameterization scheme to effectively address numerical analysis subject to the variation of the fiber radius of a square unit cell. In particular, the proposed mesh-morphing approach may lead to a parameterized weak form whose bilinear and linear forms are affine in the geometric parameter of interest, i.e. the fiber radius. As a result, we may certify the reduced basis analysis of a square unit cell model for any parameters in a predetermined parameter domain with a rigorous a posteriori error bound. To demonstrate the utility of the proposed geometric parameterization, we consider a two-dimensional, steady-state heat conduction analysis dependent on two parameters: a fiber radius and a thermal conductivity. For rapid yet rigorous a posteriori error evaluation, we estimate a lower bound of a coercivity constant via the min-θ method as well as the successive constraint method. Compared to the corresponding finite element analysis, the constructed reduced basis analysis may yield nearly the same solution at a computational speed about 29 times faster on average. In conclusion, the proposed geometric parameterization scheme is conducive for accurate yet efficient reduced basis analysis.