• 한국초등과학교육학회지:초등과학교육
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• 제19권1호
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• pp.41-56
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• 2000

The purpose of this study was to investigate the change of elementary school students' conception on the movement of the moon, after teaching a lesson about the lunar phase which focused on concrete activities. The 396 subjects in this study consisted of intact groups of second, third, fourth, fifth, and sixth grade students. Pre-test and post-test instrument concerning on the conception in the movement of the moon were developed after reviewing the related literature and curriculum. Prevailing conceptions were identified by frequency of each conception. Then, the pattern of change and consistency of each conception were analyzed in comparison pre-test with post-test. To figure out the effect of teaching, the GEFT and the GALT instrument were administered to analyze it by gender, cognition mode and level. SPSS/WIN programs were used to process the data. The result showed that teaching 'movement of the moon' was the most effective in fourth grade. The effect of teaching 'changes in shape of the moon' was effective regardless of their sexes. Teaching 'changes in shapes of the moon' was more effective for the students whose cognitive modes were field-independent, than those filed-dependent. But the improvement by the teaching was not significantly different. The pre-score by cognitive level was significantly high in the order of the formal operational, transitional stage and the concrete operational stage. But the improvement of conception after teaching was high in the order of the concrete operational, transitional stage and the formal operational stage. That is to say, teaching was more effective as the cognitive level lowered.

• 가정과삶의질연구
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• 제24권6호
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• pp.1-16
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• 2006

This study aims to investigate the Healthy Family Support Centers'(HFSCs) operational patterns and their programs by surveying 46 HFSC employees in order to prepare for the massive increase of the number of HFSCs nationwide. This study might contribute to not only rebuilding the HFSCs' operational strategies but suggesting visible ideas for the HFSCs' programs. Results were as followed: First, most HFSCs consisted of several teams, i.e., educational team, counseling team and cultural team. However, the number of employees in each team was different from one regional community to another. The most difficult task in the HFSCs' operation was publicity work. Citing the issue of system delivery difficulties, HFSC employees insisted that budgetary deficit was the most difficult obstacle in running the HFSCs. Second was in regards to the programs that each team was planning, performing, and evaluating for each program. The HFSCs' programs were mostly structured around family difficulties or problems that arise according to the family life cycle. Based on these study results, more unified and specialized programs for HFSCs should be developed. In order to achieve this related studies should continue to conducted.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.29-32
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• 2002

The developed locomotive in coal mine drawn by the parallel drive system of the double Switched Reluctance motors is introduced. The operational principles, the control pattern and the component parts of the traction and the regenerative braking operation are proposed. The drive system contributes to reduce the cost of utilization of the locomotive per ton kilometer.

• 산업경영시스템학회지
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• 제23권60호
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• pp.23-36
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• 2000

A probabilistic model of burr formation in face milling of gray cast iron is proposed. During a face milling operation, an irregular pattern of the edge profile consisting of burrs and edge breakouts is observed at the end of cut. Based on the metal cutting theory, we derive a probabilistic model. The operational bayesian modeling approach is adopted to include the relevant theory in the model.

• 태양에너지
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• 제18권2호
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• pp.51-67
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• 1998

본 고에서는 우리나라 기후조건, 온수사용 패턴 등을 고려한 일반적인 태양열 이용사례를 사용용도에 따라 태양열 온수와 태양열난반시스템으로 구분하여 소개하였다. 일반적인 태양열온수기와 개념, 구성요소 등을 살펴본 후 각 종류별 작동원리를 소개하였다. 시공방법에서는 가정용과 산업용으로 구분하여 배관구성도를 포함하야 소개하였고, 설치전 여건 파악과 제품운반부터 조립, 배관, 보온, 열매체주입, 설치후 조치까지외 모든 과정을 살펴보았다. 그리고, 태양열난방시스템의 문제점도 살펴보았다.

• Nuclear Engineering and Technology
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• 제36권3호
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• pp.210-218
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• 2004

In the interest of nuclear power plant safety, a self-diagnostic monitoring system (SDMS) is needed to monitor defects in safety-related components. An air-operated valve (AOV) is one of the components to be monitored since the failure of its operation could potentially have catastrophic consequences. In this paper, a model of the AOV is developed with the parameters that affect the operational characteristics. The model is useful for both understanding the operation and correlating parameters and defects. Various defects are introduced in the experiments to construct a fault library, which will be used in a pattern recognition approach. Finally, the validity of the fault library is examined.

• 서비스연구
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• 제9권2호
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• pp.31-40
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• 2019

본 논문은 빅데이터, 사물인터넷, 인공지능 등 정보기술의 발전과 더불어 더욱 중요해진 정보시스템의 비즈니스 연속성 증대를 위한 운영감리 개선에 관하여 연구하였다. 다양한 서비스와 데이터 그리고 산업이 융합되는 4차 산업시대에 도래하고 있는 현재 정보시스템의 운영관리와 감리지침은 기존의 범용적 정보시스템 패턴에 근거해 대응하고 있어 이에 대한 개선이 요구된다. 정해진 시간에 정해진 서비스의 제공이 기업 및 국가의 생존과 연결되고 핵심 요소로 작용하고 있으므로 비즈니스 연속성 관리차원에서 정보시스템의 서비스 중단 피해를 최소화하고 안정된 서비스 수준을 제공하기 위한 운염감리의 최적화된 방향성과 점검항목을 적용하는 연구가 필요하다. 이를 위해 정보시스템의 운영감리에서 제시하는 점검항목을 ISO 22301에서 제공하는 PDCA 단계별 내용과 8대 자원 요구사항을 접목하여 도출하였다. 점검항목의 도출기준에 따라 비즈니스 연속성 증대 관점에서 정보시스템 운영감리의 개선된 점검항목과 검토항목 그리고 운영감리 중 점검해야 할 산출물을 예시로 운영감리 점검항목을 도출하였다. 점검항목으로는 서비스 연속성 관리를 위한 운영감리 개선 점검항목과 성능, 가용성 관리를 위한 운영감리 개선 점검항목으로 구분하여 제안하였다. 제안한 점검항목의 적합성에 대한 IT전문가들의 5점 척도 설문 결과 평균 4.63으로 나타나 적합하다는 결론이 도출되었다.

• 한국정보통신학회논문지
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• 제7권1호
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• pp.100-105
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• 2003

본 논문에서는 CMOS 연산증폭기에 존재하는 모든 단락고장(short fault)과 개방고장(open fault)을 효과적으로 검출할 수 있는 새로운 테스트 방식을 제안한다. 제안하는 테스트 방식은 단위이득 대역폭(unit gain bandwidth)보다 큰 주파수를 가치는 단일 정현파를 이용한다. 이 방식은 하나의 테스트 패턴으로 모든 대상고장을 검출할 수 있으므로 테스트 패턴 생성을 위한 알고리즘이 간단하다. 따라서 패턴 생성 시간이 짧고, 테스트 비용을 줄일 수 있는 장점을 가지고 있다. 제안한 테스트 방식을 검증하기 위하여 2단 연산 증폭기를 설계하였으며, HSPICE 모의실험을 통하여 대상 고장에 대하여 높은 고장검출율(fault coverage)을 얻었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권2호
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• pp.664-677
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• 2014

Wind energy has proven its viability by the emergence of countless wind turbines around the world which greatly contribute to the increased electrical generating capacity of wind farm operators. These infrastructures are usually deployed in not easily accessible areas; therefore, maintenance routines should be based on a well-guided decision so as to minimize cost. To aid operators prior to the maintenance process, a condition monitoring system should be able to accurately reflect the actual state of the wind turbine and its major components in order to execute specific preventive measures using as little resources as possible. In this paper, we propose a fault detection approach which combines cluster analysis and frequent pattern mining to accurately reflect the deteriorating condition of a wind turbine and to indicate the components that need attention. Using SCADA data, we extracted operational status patterns and developed a rule repository for monitoring wind turbine systems. Results show that the proposed scheme is able to detect the deteriorating condition of a wind turbine as well as to explicitly identify faulty components.

• ETRI Journal
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• 제38권5호
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• pp.885-895
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• 2016

The lowest power mode (passive-standby mode) was proposed for reducing the power consumption of set-top boxes in a standby state when not receiving content. However, low-power set-top boxes equipped with the lowest power mode have been rarely commercialized because of their low-quality user experience. In the lowest power mode, they deactivates almost all of operational modules and processes, and thus require dozens of seconds for activation latency (that is, the latency for activating all modules of the set-top boxes in a standby state). They are not even updated in a standby state because they deactivate their network interfaces in a standby state. This paper proposes an adaptive standby mode scheduling method for improving the user experience of such boxes. Set-top boxes using the proposed method can analyze the activation pattern and find the frequently used time period (that is, when the set-top boxes are frequently activated). They prepare for their activation during this frequently used time period, thereby reducing the activation latency and enabling their update in a standby state.