• 한국실내디자인학회논문집
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• 제13권6호
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• pp.3-11
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• 2004

In the 21st Century, our society is facing decrease of general population and beginning of aging society due to low birth rate, and such issues are increasing the elderly population. Especially in Korea, the elderly population exceeded 7% of the total population in 2000, making its way to the aging society and the elderly population will increase up to 14% by 2019, becoming the true aging society. Unlike other countries, aging in Korea is happening very fast and this requires the society's preparation and plans to deal with the problem. This study was started with the problem that the welfare centers for elderly people in Gwangju do not have the space plan adequate for the regional characteristics and users' demands. Therefore, this study performed an investigation and analysis on service programs, management, and space formation of S welfare centers for elderly people in Gwangju. This study produced a figure after interviews with social welfare workers and surveys. And then this study investigated size and formation of space for the service programs in each welfare center This study showed the current status of welfare centers for elderly people and difference in size and formation of space related to the service programs of the region. Therefore, this study was done to provide the basic data for the space formation of new welfare centers.

• 전력전자학회논문지
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• 제20권6호
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• pp.558-565
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• 2015

Gallium nitride high-electron mobility transistor (GaN HEMT) is the strongest candidate for replacing Si MOSFET. Comparing the figure of merit (FOM) of GaN with the state-of-the-art super junction Si MOSFET, the FOM is much better because of the wide band gap characteristics and the heterojunction structure. Although GaN HEMT has many benefits for the power conversion system, the performance of the power conversion system with the GaN HEMT is sensitive because of its low threshold voltage ($V_{th}$) and even lower parasitic capacitance. This study examines the characteristics of a phase-shifted full-bridge dc-dc converter with cascode GaN HEMT. The problem of unoptimized dead time is analyzed on the basis of the output capacitance of GaN HEMT. In addition, the printed circuit board (PCB) layout consideration is analyzed to reduce the negative effects of parasitic inductance. A comparison of the experimental results is provided to validate the dead time and PCB layout analysis for a phase-shifted full-bridge dc-dc converter with cascode GaN HEMT.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.394-399
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• 2005

A case history is presented pertaining to high frequency piping vibration and noise caused by globe valve in the spent fuel pool cooling system of nuclear power plant. Frequency analyses were performed on the system to diagnose the problem and develop a solution to reduce the piping vibration and noise. The source of the high frequency and noise energy was traced to the globe valve located immediately downstream of the centrifugal pump by performing valve throttling test. Measurements of vibration and noise are presented to show that the high frequency vibration and noise amplitude was dependent upon the valve disc position and flow rate. Strouhal vortex shedding frequencies were generated at the exit of the globe valve which exited structural resonance of valve disc and amplified the high frequency vibration and noise. The problem was identified as an interaction between the flow inside globe valve and the valve disc structure. Attempts to reduce the vibration and noise amplitudes of the piping system were successfully achieved by the modification of guide-disc diameter and disc-edge figure The valve disc was replaced by an alternative to eliminate the source of the harmful high frequency vibration and noise.

• 한국수학교육학회지시리즈A:수학교육
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• 제57권4호
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• pp.477-491
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• 2018

In this paper we study in-service teachers' and pre-service teachers' recognition the domain in the problem concerning the continuity of a function. By a questionnaire survey we find out that most of in-service teachers and pre-service teachers are understanding the continuity of a function as explained in high school mathematics textbook, in which the continuity was defined by and focused on comparing the limit with the value of the function. We also notice that this kind of definition for the continuity of a function makes them trouble to figure out whether a function is continuous at an isolated point, and to determine that a given function is continuous on a region by not considering its domain explicitly. Based on these results we made several suggestions to improve for in-service teachers and pre-service teachers to understand the continuity of a function more exactly, including an introduction of a more formal words usage such as 'continuous on a region' in high school classroom.

• Nuclear Engineering and Technology
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• 제56권7호
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• pp.2748-2755
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• 2024

This paper presents two new methods for variance reduction for shielding calculation in Monte Carlo radiation transport. One method is CADIS-NEE, which combines Consistent Adjoint Driven Importance Sampling (CADIS) and next-event estimator (NEE) methods to increase the calculation efficiency of tallies at points. The other is CADIS-deterministic transport (DXTRAN), which combines CADIS and DXTRAN to obtain higher performance than using CADIS and DXTRAN separately. The combination processes are derived and implemented in the hybrid Monte-Carlo-Deterministic particle-transport code NECP-MCX. Various problems are tested to demonstrate the effectiveness of the two methods. According to the results, the two combination methods have higher efficiency than using CADIS, NEE or DXTRAN separately. In a long-distance photon-transport problem, CADIS-NEE converges faster than NEE and the figure of merit (FOM) of CADIS-NEE is 75.6 times of NEE. In a labyrinthine problem, CADIS-DXTRAN's FOM surpasses that of DXTRAN and CADIS by a factor of 45.3 and 17.7, respectively. Therefore, it is advisable to employ these two novel methods selectively in appropriate scenarios to reduce variance.

• 대한수학교육학회지:학교수학
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• 제9권2호
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• pp.241-257
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• 2007

일반적으로 영재교육 대상자 선발을 위해 실시되는 지필평가는 학생에 대한 자세한 정보를 제공하지 않기 때문에, 보다 세부적인 정보를 수집해서 신중하게 판별하고 교육해야 한다. 또한 수학영재로 선발되었으나 교육과정에 적응하지 못하는 학생들도 상당수 있기 때문에, 학생들이 교육과정에 참여하는 양상에 대한 자세한 정보도 중요하다. 이 연구에서는 영재교육 대상자로 선발되었으나 영재교육 과정에서는 여러 가지 이유로 학습에 어려움을 표현하는 학생들, 선발과정에서는 상대적으로 낮은 수준에 있는 것으로 판별되었으나 영재교육 과정에서는 높은 수준의 수행을 보여주는 학생들의 특성을 자세하게 살펴보았다. 이를 통해 관찰평가, 창의력평가는 지필평가에 의해서는 얻기 어려운 학생들에 대한 세부적인 정보를 얻을 수 있고, 영재교육 과정에서의 수행 수준에 대한 예측력이 높은 정보를 제공한다는 것을 확인하였다.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제31권2호
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• pp.223-239
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• 2017

이 논문에서는 초등 영재학생들에게 수학화의 경험을 주기 위한 교수단원 <삼 사각형의 등주문제>를 설계하는 것이 목적이다. 이를 위해서, 각 조별 학생들의 문제 해결과정 중에 나타나는 사고과정을 바탕으로 교사와 수업관찰자(연구자)가 수업분석을 통하여 교수단원 설계와 관련된 논의를 하였다. 교육적 시사점을 줄 수 있는 논의 내용을 요약하면 다음과 같다. 첫째, 학생들의 인지적인 간극을 줄이기 위한 교구활용을 고려해야한다. 둘째, 삼각형에서 삼각형이 지닌 속성인 변의 개념과 추상적인 속성인 높이 개념과의 관계를 심도 있게 다룰 필요가 있다. 셋째, 귀납적인 추론으로부터 시작하여 추론을 정당화하는 낮은 수준의 연역적인 논리가 필요하다. 끝으로, 도형을 보는 직관(spatial sense)에 영향을 줄 수 있는 도형의 개념이미지를 조사할 필요성이 있다.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제38권2호
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• pp.247-261
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• 2024

본 연구는 스크래치 같은 드래그 앤 드롭 방식 교육용 프로그래밍 언어를 활용하여 복잡한 도형의 한붓그리기 과제를 해결하는 활동의 교육적 활용가능성을 논의하고자 한다. 주어진 도형이 한붓그리기가 가능한지를 판별하는 문제와 실제로 한붓그리기의 경로를 찾아서, 프로그래밍으로 구현하는 것은 별개의 문제가 된다. 특히 규칙성을 가지는 복잡한 도형에 대해 한붓그리기가 가능한 규칙적인 경로를 찾고, 이를 프로그래밍으로 구현하는 것은 다양한 수학지식의 융합을 바탕으로 하는 문제해결 역량을 요구한다. 이에 본 연구에서는 다각형 관련 도형들, 테셀레이션 관련 도형들, 프랙탈 도형들 중에 한붓그리기와 관련된 문제를 제시하고, 해당 도형의 한붓그리기 프로그래밍 결과를 예시하였다. 또 예시된 문제의 해결과정을 위해 필요한 수학지식과 계산적 사고 요소들을 분석하였다. 본 연구는 수학과 정보가 융합하는 수학교육에 대한 새로운 예시라는 의미를 갖는다.

• 디지털산업정보학회논문지
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• 제12권3호
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• pp.55-64
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• 2016

Recently, unmanned aerial vehicle, also known as drone is being used in variety of areas. Previously drones are used as military purposes. After unmanned technology went abroad to civil, drones are used as multipurpose such as hobby, business and other more. Even though drones are very useful in many areas, problems such as safety and personal privacy infringement raised new social issues. In this thesis it will analyze and suggest solutions to the social problems of personal privacy infringement which occurred by drone filming. This thesis will also suggest that new law of drone safety must legislate quickly. Drone is exploration of new filed. Varies of new technology help to grow drone industries. Drone is able to complete tasks which are impossible or very difficult to do. To constantly grow drone industries, people must have solutions for problems of drone. If people can figure out solutions problem of drone which introduced by this thesis, value of drone will grow even more.

• 대한치과의사협회지
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• 제53권2호
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• pp.103-110
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• 2015

The dental accidents and disputes among Korean dentists have been on the increase with time. The main purpose of this study is to figure out the actual status of the dental accidents and malpractice disputes based on a questionnaire survey. The findings showed that 64.8% of respondents had been experienced the dental accidents, and 52.9% of respondents had been locked into the disputes. Within 5 years from the start of dental practice, the nearly half of the dentists responded the experience of the dental accidents and disputes. The amount of compensation for dental accidents and disputes wereindentalimplant, prosthodontics, and oral surgery treatments in descending order. The highest incident type was wrong process/treatment/procedure problem in clinical process/procedure.