• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.631-637
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• 2005

This paper presents a stiffness analysis method for a low-DOF parallel manipulator, which takes into account of elastic deformations of joints and links. A low-DOF parallel manipulator is defined as a spatial parallel manipulator which has less than six degrees of freedom. Differently from the case of a 6-DOF parallel manipulator, the serial chains in a low-DOF parallel manipulator are subject to constraint forces as well as actuation forces. The reaction forces due to actuations and constraints in each limb can be determined by making use of the theory of reciprocal screws. It is shown that the stiffness model of an F-DOF parallel manipulator consists of F springs related to the reciprocal screws of actuations and 6-F springs related to the reciprocal screws of constraints, which connect the moving platform to the fixed base in parallel. The $6{times}6$ stiffness matrix is derived, which is the sum of the stiffness matrices of actuations and constraints. The six spring constants can be precisely determined by modeling the compliance of joints and links in a serial chain as follows; the link can be considered as an Euler beam and the stiffness matrix of rotational or prismatic joint can be modeled as a $6{times}6$ diagonal matrix, where one diagonal element about the rotation axis or along the sliding direction is zero. By summing the elastic deformations in joints and links, the compliance matrix of a serial chain is obtained. Finally, applying the reciprocal screws to the compliance matrix of a serial chain, the compliance values of springs can be determined. As an example of explaining the procedure, the stiffness of the Tricept parallel manipulator has been analyzed.

• The International Journal of Costume Culture
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• 제3권3호
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• pp.212-222
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• 2000

This study intends to observe how the essential elements of art have changed Human's sense of beauty extending over the whole lives as well as fashion through the investigation of Light and Rays which have played a important role in giving birthe to the new trend of art within the upheaval age of various cultures. The peculiarities of which Futurism of Italy and Rayonism of Russia including Impressionism have a great role in giving birth to a new trend of art by means of the development of science technology are like these. Impressionists looked for the origin of the subtle harmony in nature within changes of sun-rays. The special feature of Impressionism paintings was to express the line of vision diversely according to changes of light rather than to focus on the line of vision with clear outlines. Henceforth, Neo-Impressionism which developed Impressionism more systematically leaded changes of Light and Rays more systematically and scientifically and maintained Divisionnisme techniques which extends to lead towards color and light through dividing and juxtaposing color. In the early 20th century Futurists tried to express dynamism through the interpenetration of light and revive color and light through the division techniques of color and persist an artificial light like eletricity rather than a natural light. Rayonism of Russia which was ifluenced from Impressionism and Futurism maintained intersection of reflecting rays which emerges from an object of things more deeply. This pursuit of light and rays also light and rays also appears as it is in modern fashion. First, it is the fashion which applied sun-rays persisted by Impressionists and expressed colors which show differently according to direction of light. Second, it is the fashion design which re-analyzed what Futurists expressed artificial light and rays. Third, it is the design which expressed Divisionnisme theory persisted by Impressionists and Futurists into fashion as it is and was made of being divided the form of glittering light into small dots. Fourth, it is the fashion design which applied Rayonists'work which applied intersection of reflected rays. Like this, it is aproved that the pursuit of light and rays expresses as it is in modern fashion of the 21st.

• 융합보안논문지
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• 제15권3_2호
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• pp.11-19
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• 2015

이 논문은 그동안 민간조사제도 도입에 관하여 논의되어 왔던 쟁점들에 대한 연구동향을 분석하여 그 시사점을 돌출함으로써, 바람직한 도입 방향을 제시하는데 연구목적을 두고자 한다. 분석한 쟁점들은 민간조사제도 도입에 관한 기존의 연구물들을 대상으로 추출하였다. 연구자들이 지적한 쟁점사항들은 명칭, 업무범위, 법인, 자격제도(자격기준 및 시험), 교육, 협회설립, 감독기관, 입법형태 등 8개의 범주안에 포함된다. 명칭에 대해서는 '탐정'이라는 명칭으로 통일할 필요가 있다고 본다. 업무범위에 대해서는 개정이 어려운 법률에서는 일반적인 업무규정을 개괄적으로 두고, 보다 구체적이고 세부적인 조사업무내용은 시행령을 통하여 규율하는 것이 합리적이라 할 수 있다. 민간조사제도는 법인으로의 제한적 운영이 필요하다고 본다. 교육에 대해서는 민간조사 종사자에 대한 신임교육과 재교육이 정기적으로 이루어져야 한다. 관리감독기관에 대해서 경찰청으로 일원화하여야 한다. 입법형태는 독자적인 법률로 규정하는 것보다는 경비업법의 개정을 통해 민간조사제도에 대하여 보완 규정하는 것이 효과적일 수 있다는 것이다.

• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2008년도 춘계 학술발표회 논문집
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• pp.101-106
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• 2008

본 연구에서는 서로 상이한 최적화기법인 유전알고리듬과 수학적 프로그래밍기법을 이용하여 지오데식 돔 구조물을 최적화하고 그 결과를 분석하였다. 본 연구에서 도입한 유전알고리즘은 유전연산자인 선택, 교배, 돌연변이 이외에도 재생기법을 도입하여 최적해의 검색성능을 높였다. 그리고 수학적인 프로그래밍기법은 유한차분법을 이용하여 목적함수의 설계민감도를 계산하였으며 세 가지의 다른 검색기법을 이용하여 돔의 크기최적화를 수행하였다. 지오데식 돔의 중앙에 작용하는 집중하중에 저항하는 돔의 각 부재의 크기패턴을 자체 개발된 $ISADO-GA{\alpha}$와 ISADO-OPT를 이용하여 최적 설계하였다. 본 연구를 통하여 제시된 최적결과는 정해가 존재하지 않는 실제 구조물의 최적 값에 대한 유용한 정보를 제공할 뿐만이 아니라 향후 대공간구조의 새로운 구조시스템 개발의 밑거름이 될 것으로 판단된다.

• 한국지반공학회논문집
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• 제18권2호
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• pp.65-74
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• 2002

지중응력의 측정은 터널 및 지하구조물의 변위와 응력분포를 예측하는데 중요하다. 본 연구에서는 남부 한반도 지역의 지중응력 분포를 음력해방법과 수압파쇄법으로 측정된 새로운 380개의 자료를 통하여 재평가와 이를 고려한 삼차원 터널해석을 실시하였다. 지중응력분포의 결과에 의하면 변성암과 화강암지역의 수평응력분포는 퇴적암과 화산암의 분포에 비하여 불규칙한 경향을 보이고 있다. 화산암 지역에서는 수직응력에 대한 수평음력의 비(측압계수, K)는 150m 깊이 이상 심도에서 1보다 작다. 또한, 국내에서는 처음으로 측정된 지중응력에 대한 삼차원 방향과 크기를 동시에 그림으로 나타내었다. 삼차원 터널 해석에 의하면, 터널 주변의 변위에 대한 방향과 크기는 최대수평음력과 최소수평응력의 차이에 의하여 주로 영향을 받고 있다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.187-190
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• 2006

In the present study, effects of tree-stream turbulence and surface trip wire on the flow past a sphere at $Re\;=\;0.4\;{\times}\;10^5\;{\sim}\;2.8\;{\times}\;10^5$ are investigated through wind tunnel experiments. Various types of grids are installed upstream of the sphere in order to change the tree-stream turbulence intensity. In the case of surface trip wire, 0.5mm and 2mm trip wires are attached from $20^{\circ}\;{\sim}\;90^{\circ}$ at $10^{\circ}$ interval along the streamwise direction. To investigate the flow around a sphere, drag measurement using a load cell, surface-pressure measurement, surface visualization using oil-flow pattern and near-wall velocity measurement using an I-type hot-wire probe are conducted. In the variation of free-stream turbulence, the critical Reynolds number decreases and drag crisis occurs earlier with increasing turbulence intensity. With increasing Reynolds number, the laminar separation point moves downstream, but the reattachment point after laminar separation and the main separation point are fixed, resulting in constant drag coefficient at each free-stream turbulence intensity. At the supercritical regime, as Reynolds number is further increased, the separation bubble is regressed but the reattachment and the main separation points are fixed. In the case of surface trip wire directly disturbing the boundary layer flow, the critical Reynolds number decreases further with trip wire located more downstream. However, the drag coefficient after drag crisis remains constant irrespective of the trip location.

• 한국재난정보학회 논문집
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• 제5권2호
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• pp.50-73
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• 2009

This paper is about the establishment of "Initial Response System." Initial response system is most important and should be treated urgently among all preparations for chemical terrorism. The objects of Initial response system are to protect civilians and the first responder who are exposed directly to chemical terrorism. Therefore, this paper suggests two main issues about Initial response system. One is to prepare immediate and exact information service system which assures the safety and survival of exposed people. The other is to build Scene Response System integrated with Command-Control Procedure for early finished situation. Compared to United States, overcoming the Chemical Terrorism requires to improve the contents of two categories: Counter Citizen Response part and Initial Scene Response part. For Counter citizen response part' s sake, the web-sites of Response leader agencies for searching information about chemical terrorism should be modified specifically. These web-sites have to be re-organized in detail. The existing Information service system which has been vaguely informed as "CBRNE Accident" needs to be divided as "CBRNE Accident" and "WMD terrorism." Further, each of them should be specialized in "Chemical', "Biological", and "Radiological" categories. There is a need to rearrange current Emergency Instruction for civilians against chemical terrorism in feasible way. At the same time, it should be applied consistently to all organizations through agreement between experts and related-organizations. For Initial Scene Response part's sake, "Initial scene response procedure (SOP)" and "Operational conception" should be produced through Simulated Exercises and workshops of all organizations related with initial response. These organizations have to cooperate with Ministry of Environment which is the main leader Agency as the center. Next, there is a need to develop a technology and Scene Response Equipments, and to standardize the response equipments which consider the capability of First Responders for chemical terrorism. Especially, improving capability of equipments is required to overcome the vulnerability of Scene Response Equipments.

• 한국전기전자재료학회논문지
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• 제29권5호
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• pp.268-273
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• 2016

In this study, we observed current-voltage characteristics of the MIM (metal-insulator-metal) structure. The $WO_x$ material was used between metal electrodes as the oxide insulator. The structure of the $Al/WO_x/TiN$ shows bipolar resistive switching and the operating direction of the resistive switching is clockwise, which means set at negative voltage and reset at positive voltage. The set process from HRS (high resistance state) to LRS (low resistance state) occurred at -2.6V. The reset process from LRS to HRS occurred at 2.78V. The on/off current ratio was about 10 and resistive switching was performed for 5 cycles in the endurance characteristics. With consecutive switching cycles, the stable $V_{set}$ and $V_{reset}$ were observed. The electrical transport mechanism of the device was based on the migration of oxygen ions and the current-voltage curve is following (Ohm's Law ${\rightarrow}$ Trap-Controlled Space Charge Limited Current ${\rightarrow}$ Ohm's Law) process in the positive voltage region.

• 의학교육논단
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• 제22권3호
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• pp.173-188
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• 2020

Medical humanities education (MHE) is as essential as basic medical sciences and clinical medicine education. Despite the importance of MHE, MHE curriculum development (CD) has proven to be challenging. This critical review examines the MHE CD at one medical school. The critical review methodology was developed based on Kern's six step CD model to systematically examine the CD of "Doctoring and Medical Humanities (DMH)" at the Yonsei University College of Medicine. Five review questions were developed related to (1) necessity, (2) direction and purpose, (3) design, (4) operation, and (5) evaluation of CD based on Kern's model. The review showed that the process of DMH CD mapped to components of Kern's model. The DMH curriculum content selected was closely related to medical practice and aimed to combine the acquisition of understanding and skills by designing a student-participatory curriculum based on clinical cases. Assessment methods that emphasized students' reflections were actively introduced in the evaluation section. Since the regular committee for DMH continued the work of the special ad hoc committees for DMH CD, the CD was effectively completed. However, the planning and evaluation functions and responsibilities of the DMH committee need to be strengthened. Despite the apparent limitations, the fact that students showed a high satisfaction rate and preferred small group discussions based on clinical cases has significant implications in the instructional design of MHE, where changes in self-awareness and attitude are more important than the acquisition of information. It is necessary to systematically review and study students' reflection results produced by the changed assessment methods and to develop assessment indicators for MHE that reflect the achievements of the MHE competencies of students.

• 한국멀티미디어학회지
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• 제14권4호
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• pp.88-98
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• 2010

지금은 급속도로 발전하는 ICT(정보통신기술)뿐만 아니라 BT, CT, NT, ST 들이 컨버전스하는 고도의 통합기술이 활용되는 유비쿼터스시대이다. 이들 기술로 시간과 공간의 벽을 넘어 인간의 5감을 크게 도와주는 3차원 가상현실 시각화기술을 이해함은 최근에 매우 중요하게 되었다. 본 연구는 3차원 가상현실 시각화 기술을 살피고 향후의 발전 방향을 예측하고 전망과 제언을 하는 것이다. 가상현실 구현기술은 3차원 컴퓨터그래픽스 표현기술에 크게 종속되어 있어 몰입할 수 있는 3차원 영상 구현기술이 가능하였고, 또한 컴퓨터의 상호작용성을 이용하여 새로운 패러다임으로 영상을 증강시키는 PC와 디스플레이 장비를 기반으로 구현되고 있으며, 보다 인간성을 강조하는 방향으로 활발히 연구되고 있다. 이 기술은 초고속 인터넷 기술 등의 상위기술들의 해결로 명실상부한 21세기 유비쿼터스사회 구현에 큰 몫을 감당할 것이 확실하다.