• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.487-490
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• 1999

In this paper we propose an efficient content-based image retrieval method using the color and wavelet based features. The color features are extracted from color histograms of the global image and the wavelet based features are extracted from the invariant moments of the high-pass band image through the spatial-frequency analysis of the wavelet transform. The proposed algorithm, called color and wavelet features based query(CWBQ), is composed of two-step query operations for efficient image retrieval: the coarse level filtering operation and the fine level matching operation. In the first filtering operation, the color histogram feature is used to filter out the dissimilar images quickly from a large image database. The second matching operation applies the wavelet based feature to the retained set of images to retrieve all relevant images successfully. The experimental results show that the proposed algorithm yields more improved retrieval accuracy with computationally efficiency than the previous methods.

• 한국태양에너지학회 논문집
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• 제26권1호
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• pp.49-55
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• 2006

The Multipurpose BIPV System(MBIPVS) was evaluated as an effective passive system through analyzing the thermal performance and the efficiency of PV power generation in the previous papers. To achieve the performance better, the operation method should be determined by considering physical conditions in each occasion. Thus, we cheesed the reference operation methods in each season set by the overview of the meteorological data for last 6 years, In-choen, and compared them with the various alternatives that we had made up with for improving thermal performance. The results from adopting various alternatives on MBIPVS showed that the appropriate operational model would be effective to the energy savings ; we could reduce the total loads 1,051.0[kWh] in summer and 108.9[kWh] in winter.

• 한국컴퓨터정보학회논문지
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• 제21권9호
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• pp.149-156
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• 2016

This paper is concerned with education courses operating practices for basic computer literacy training. In this study, we propose an example for students to effectively measure and evaluate the achievement of defined ability in the performance measurement and analysis, learning objectives and learning outcomes set in operation throughout the course. Through research and development use case presents the tools for teaching method and effective and objective measurement of the related subjects. And based on the results, we propose the possibility of utilizing NCS-based course operation and education certification. In this study, the measurement process is based on the association with the objective of the development and operation, and measurement tools, measuring tools for measuring learning outcomes associated with the curriculum design methods for the measurement and evaluation of the case of the operation of the course units of learning outcomes and the method proposed.

• 산업공학
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• 제12권2호
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• pp.346-353
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• 1999

In this paper, the optimum drilling operation sequence which results into the minimum overall machining time required to produce a (multi-diameter) hole is identified. The operation sequence is defined as the set of ordered operations used for producing a (multi-diameter) hole. The overall machining time is derived by summing the minimum machining times of each operation assigned to a sequence. The operations represent the drilling actions of certain sizes to produce the related holes. The minimum machining time of each operation is obtained by solving the optimization problem. Finally, this paper will identify the effects of machining constraints on the overall machining times and their relationships to sequence selection.

• 한국안전학회지
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• 제8권4호
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• pp.133-138
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• 1993

The stable and safe operation of a boiler system is essential for ensuring stability of the chemical processes. A dynamic simulation of a boiler drum was performed to identify the dynamics of the boiler drum. The obtained results represented that the variation of process variables disturb boiler system. So, disturbance rejection with tracking and constraints handing was necessary for stable operation of boiler drum. Among many controller, GPC has been known to show good performance in set point tracking than disturbance. In order to improve disturbance rejection performance measurable disturbance term was Introduced in basic GPC model. The controller which had tracking and disturbance rejection was designed for Improving the stable operation of a boiler system.

• 한국항공운항학회지
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• 제17권4호
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• pp.55-62
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• 2009

The Prime objectives of this study are to identify and analyze possible solutions and select a solution for the specification and operation plan of the meteorological purpose aircraft in Korea. Infrastructure like meteorological purpose aircraft and aircraft operating systems should be set up and their efficient plan must be established to improve meteorological technic in Korea. As a result of the study, we have found that the turboprop engine powered aircraft is the most suitable to initial model for the meteorological purpose aircraft. It was found that the indirect operation method might be the best solution, also. The results of this study may be useful to make decision for selecting specification and operation of the meteorological purpose aircraft.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제24권2호
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• pp.385-413
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• 2010

본 연구는 2007년 개정 수학과 교육과정의 목표에 새롭게 부각된 수학적 의사소통에 대한 중요성을 바탕으로 우리나라 초등학교에서 구현 가능한 수학적 의사소통 목표를 설정하기 위한 것이다. 구현 가능하도록 하기 위해 교사들이 이해하기 쉽도록 수학적 의사소통 유형을 전달방식에 따라 담화, 표현, 조작, 복합으로 구분하였으며, 학생 수준에 따른 수준별 교수 학습이 가능하도록 수학적 의사소통 유형별로 저 중 고학년에 따른 성취요소와 목표를 설정하였다. 성취요소와 목표 설정에 있어 타당성을 높이고자 전문가와 현장 교사들의 의견을 수렴하였다. 전문가와 교사 집단의 의견 중 각각 10%이상 부적절하다고 응답한 경우 판단 이유를 파악하여 삭제하거나 수정하였으나, 일부 특정 요소의 경우 국제적 동향이나 선행연구를 토대로 이상적인 목표로 문제가 없다고 판단될 경우 그대로 두거나 학년 이동만 한 것도 있다. 본 연구에서 설정된 초등학교 수학적 의사소통 성취요소와 목표는 수학교실에서 실질적으로 학생들의 다양한 수학적 의사소통을 돕고, 학생 수준을 파악하는데 큰 도움이 되길 기대한다.

• 수산해양기술연구
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• 제59권1호
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• pp.44-54
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• 2023

In this study, the second-order Nomoto's nonlinear expansion model was implemented as a Tagaki-Sugeno fuzzy model based on the heading angular velocity to design the automatic steering system of a ship considering nonlinear elements. A Tagaki-Sugeno fuzzy PID controller was designed using the applied fuzzy membership functions from the Tagaki-Sugeno fuzzy model. The linear models and fuzzy membership functions of each operating point of a given nonlinear expansion model were simultaneously tuned using a genetic algorithm. It was confirmed that the implemented Tagaki-Sugeno fuzzy model could accurately describe the given nonlinear expansion model through the Zig-Zag experiment. The optimal parameters of the sub-PID controller for each operating point of the Tagaki-Sugeno fuzzy model were searched using a genetic algorithm. The evaluation function for searching the optimal parameters considered the route extension due to course deviation and the resistance component of the ship by steering. By adding a penalty function to the evaluation function, the performance of the automatic steering system of the ship could be evaluated to track the set course without overshooting when changing the course. It was confirmed that the sub-PID controller for each operating point followed the set course to minimize the evaluation function without overshoot when changing the course. The outputs of the tuned sub-PID controllers were combined in a weighted average method using the membership functions of the Tagaki-Sugeno fuzzy model. The proposed Tagaki-Sugeno fuzzy PID controller was applied to the second-order Nomoto's nonlinear expansion model. As a result of examining the transient response characteristics for the set course change, it was confirmed that the set course tracking was satisfactorily performed.

• 한국전자통신학회논문지
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• 제11권4호
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• pp.395-402
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• 2016

DC ${\mu}$-Grid 기반의 충/방전 시스템에서 배터리의 동작 변환 시, 망 전압의 fluctuation이 발생하게 되며, 과다한 fluctuation은 충/방전 시스템의 손상 및 고장을 일으킬 수 있다. 따라서 본 논문에서는 DC ${\mu}$-Grid 기반의 충/방전 시스템에서 fluctuation 완화용 커패시터의 적용 및 설계 포인트에 대하여 연구하였다. 컴퓨터 시뮬레이션 결과, 3개의 충전 배터리 set와 5개의 방전 배터리 set의 조건으로 운영되는 DC ${\mu}$-Grid 기반 충/방전 시스템에서 600V/35mF의 초기 값을 갖는 fluctuation 완화용 커패시터를 적용하였을 때 충/방전에 의한 fluctuation을 약 66.3% 감소시킬 수 있었으며, 추가적으로 초기 망 전압 안정화 시 발생하는 fluctuation 또한 약 73% 감소시킬 수 있었다.

• 대한기계학회논문집B
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• 제35권6호
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• pp.593-601
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• 2011

다양한 작동 조건에서 고분자 전해질형 연료전지의 성능 변화를 예측하기 위한 해석 프로그램을 구성하여 열관리가 시스템의 성능에 미치는 영향을 해석하였다. 전체 시스템은 연료전지 스택, 공기공급계, 연료공급계, 열 관리계로 구성 되었으며 각 구성부의 설계점을 고려하여 열역학적 모델링을 적용 하였다. 외기온 변화와 냉각 시스템의 성능 변화에 따라 연료전지 스택의 온도 및 출력 변화가 예상되므로 탈설계 해석을 하여 전체 시스템의 성능 변화를 예측하였다.