• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.269-274
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• 2011

A CFD analysis was performed to examine the inner channel blockage of dual-cooled fuel which has being developed for the power uprate of a pressurized water reactor (PWR). The dual-cooled fuel consists of an annular fuel pellet($UO_2$) and dual claddings as well as internal and external cooling channels. The dual-cooled annular fuel is different from a conventional solid 려el by employing an internal cooling channel for each fuel pellet as well as an external cooling channel. One of the key issues is the hypothetical event of inner channel blockage because the inner channel is an isolated flow channel without the coolant mixing between the neighboring flow channels. The inner channel blockage could cause the Departure from Nucleate Boiling (DNB) in the inner channel that eventually causes a fuel failure. This paper presents the CFD simulation of the flow through the side holes of the bottom end plug for the complete entrance blockage of the inner channel. Since the amount of coolant supply to the inner channel depends on largely the pressure loss at the side hole, the pressure loss coefficient of the side hole was estimated by the CFD analysis. The CFD prediction of the loss coefficient showed a reasonable agreement with an experimental data for the complete blockage of both the inner channel entrance and the outer channel. The CFD predictions also showed the decrease of the loss coefficient as the outer channel blockage increases.

• Steel and Composite Structures
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• 제26권1호
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• pp.79-87
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• 2018

In order to study the natural vibration characteristics of steel-concrete composite truss beam (SCCTB), the influence of multiple factors such as interface slip, shear deformation and moment of inertia are considered. Afterwards, based on the Hamilton principle the vibration control differential equation and natural boundary conditions of SCCTB are deduced. By solving SCCTB differential equations of vibration control, an analytical calculation method is proposed for analyzing the natural vibration characteristics of SCCTB. The natural frequencies of SCCTBs with different degrees of shear connection and effective lengths are calculated by using the analytical method, and the results are compared against those obtained from ANSYS finite element numerical calculation method. The results show that the analytical method considering the influence factors such as interface slip, shear deformation and moment of inertia are in good agreement with those obtained from ANSYS finite element numerical calculation method. This evidences the correctness of the analytical method and show that the method proposed exhibits improvement over the previously developed theories for the natural vibration characteristics of SCCTB. Finally, based on the analytical method, the influence factors of SCCTB natural vibration characteristics are analyzed. The results indicate that the influence of interface slip stiffness on SCCTB's natural frequency is more than 10% and therefore cannot be neglected. Moreover, shear deformation has an effect of more than 35% on SCCTB's natural frequency and the effect cannot be ignored either in this case too.

• Steel and Composite Structures
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• 제26권6호
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• pp.793-808
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• 2018

In this study, the seismic performance of the connections between L-shaped columns composed of concrete-filled steel tubes (L-CFST columns) and H-beams used in high-rise steel frame structures was investigated. Seven full-scale specimens were tested under quasi-static cyclic loading. The variables studied in the tests included the joint type, the axial compression ratio, the presence of concrete, the width-to-thickness ratio and the internal extension length of the side plates. The hysteretic response, strength degradation, stiffness degradation, ductility, plastic rotation capacity, energy dissipation capacity and the strain distribution were evaluated at different load cycles. The test results indicated that both the corner and exterior joint specimens failed due to local buckling and crack within the beam flange adjacent to the end of the side plates. However, the failure modes of the interior joint specimens primarily included local buckling and crack at the end plates and curved corners of the beam flange. A design method was proposed for the flexural capacity of the end plate connection in the interior joint. Good agreement was observed between the theoretical and test results of both the yield and ultimate flexural capacity of the end plate connection.

• 한국산학기술학회논문지
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• 제18권10호
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• pp.588-596
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• 2017

외국인 직접투자가 개발도상국가들의 경제성장에 매우 중요하다고 많은 정책입안자들과 학자들이 주장하고 있음에도 불구하고 외국인 직접투자 유입과 경제 성장 간의 긍정적인 관계에 대해서는 보편적인 합의가 이루어지지 않고 있다. 그럼에도 불구하고 많은 개발도상국들이 자국의 경제성장을 위하여 적극적으로 외국인 직접투자를 유치하고 있다. 이에 본 논문에서는 1995년부터 2009년까지의 88개 개발도상국가들의 자료를 활용하여 외국인 직접투자와 경제성장 간의 관계를 실증분석 한다. 분석에 사용된 국가들은 소득수준이 높은 선진국, 석유 생산국가 그리고 가용 가능한 자료가 부족한 국가들을 제외하였다. 분석에 적용된 모형은 솔로우 모형으로 본 모형은 외국인 직접투자뿐만 아니라 실물자본, 인구증가, 인적자본을 동시에 고려하였다. 분석 결과, 외국인직접투자는 개발도상국의 경제성장에 긍정적인 역할을 하는 것으로 나타났다. 뿐만 아니라 실물자본, 인적자본 모두 개발도상국가들의 경제에 긍정적인 영향을 미치고 있는 것으로 분석되었다. 따라서 개발도상국들은 외국인 직접투자를 통해 효율적으로 경제성장을 위하여 도로, 철도, 전력, 병원과 같은 사회간접자본에 대한 투자와 인적자본에 대한 투자가 필요한 것으로 보인다.

• 대한간호학회지
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• 제37권3호
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• pp.381-390
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• 2007

Purpose: The purpose of this study was to understand the experiences of mental health hospital workers. Methods: Participants in the study were a total of 8 mental health hospital workers who consisted of nurses, social welfare workers and health managers. To prevent them from being omitted, the interviews were all recorded under the participants prior agreement. The method was analysis using the phenomenological method proposed by Colaizzi(1978). Results: The experiences of the participants of this study were classified into 15 significant areas, from which 10 subjects hard work, conflicts, heavy feeling, irritability, getting familiar, changes of recognition, aptitude determination, feeling of achievement and sense of pride were drawn out. These subjects were then grouped into 5 themes. These five themes were finally grouped into 5 categories, negative emotion, depressive emotion, changes of thinking, delight and value discovery. Conclusions: The study tried to analyze the experiences of key informants like nurses, social welfare workers and health managers all of whom were serving at mental health hospitals, contribute to social recognition about the special medical establishment, promote qualitative mental health nursing and further provide educational information necessary for understanding mental health hospital workers.

• 한국통신학회논문지
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• 제29권3C호
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• pp.426-435
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• 2004

AAA는 다양한 응용 서비스에 대한 신뢰성을 보장하기 위해 인증, 권한 검증, 과금 등의 기능을 제공하고 있으며, IETF에서는 차세대 AAA 프로토콜로 DIAMETER를 제안하고 있다. 또한 VoIP용 호 설정 프로토콜로서 제안된 SIP(Session Initiation Protocol)는 앞으로의 통신망에서 핵심기능을 담당할 것이며, SIP 서비스에 대한 신뢰성을 보장하기 위해서는 AAA와의 연동이 필요하다. 그러나 SIP에서 사용자 인증을 위한 digest 인증 메커니즘은 man-in-the-middle attack이나 dictionary attack에 취약성을 갖고 있다. 본 논문은 유무선 통합 시그널링 프로토콜로 정착될 SIP와 신뢰성 있는 서비스를 제공하기 위한 AAA 프로토콜인 DIAMETER 간의 인증 연동 방안과 인증 연동에서의 안전성을 분석하였다. 또한 보안상의 취약성 해결을 위해 주소 정보를 포함한 인증 정보의 생성 방안과 패스워드 기반의 상호인증 및 세션키 교환을 위해 AKE-ECC를 적용하는 방법을 제안하였다.

• 한국산학기술학회논문지
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• 제14권11호
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• pp.5979-5986
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• 2013

본 연구에서는 복합재료 적층 쉘 구조의 기하학적 비선형 동적 거동을 상세 분석하였다. Sanders의 1차 전단 변형 쉘이론 및 비선형 방정식을 기반하여, 비선형 동적 방정식의 해는 Newmark 방법과 Newton-Raphson 반복법을 혼용하여 적용하여 산정하였다. 본 연구에서 개발한 유한요소 해석프로그램을 사용하여 쉘의 곡률, 화이버 보강각도 및 적층 배열의 변화가 적층 쉘의 기하학적 비선형 동적 거동에 미치는 영향을 상세 분석하였다. 몇 가지 수치해석 결과는 기존 문헌으로부터 얻어진 결과와 잘 일치하는 것으로 나타났다. 본 연구의 새로운 결과는 최대 동적변위에 대한 적층 쉘 구조의 곡률, 화이버 보강각도 그리고 적층 배열 형식과의 중요한 상호관계를 보여준다. 몇 가지 수치해석 예제는 동적 특성을 고려한 적층 쉘 구조를 상세 설계하는데 필요한 가이드라인을 제시할 수 있을 것으로 기대된다.

• 한국의류학회지
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• 제33권1호
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• pp.45-54
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• 2009

The reform of dress regulation in Kapshin(甲申衣制改革; 1884) was the first dress renovation in 8 years after Chosun's port opening in 1876, and the key contents of that reform was the simplification of the formal dress and private dress. The reform in the culture of the traditional costume should require some kind of special experience because that culture had been regarded as the precious symbol of the Confucianism. The purpose of this study is to investigate the background of "the reform" and who proposed "that reform", by contemplating the costume and the thought of costume of the ambassador extraordinary(修信使) and the Inspectors detached to Japan(朝士視察團) who experienced new costume system of Japan sent by Chosun Dynasty. For this study, historical documents such as 'Sillok(實錄)', a sort of report("修信使記錄", "聞見事件") were reviewed and the evidential photos in Japan were analyzed. It can be summarized as follows. First, Kim Kisu(金綺秀, Susinsa) in 1876 and Kim Hongjip(金弘集, Susinsa) in 1880 wore the traditional costume of Chosun in Japan, and described the westernized Japanese costume in view of traditional costume culture. Second, the inspectors detached to Japan in 1881 showed the same attitude to the Japanese costume as the previous Susinsas had done. Third, Park Younghyo(朴泳孝), who was an ambassador extraordinary and plenipotentiary(特命全權大使) in 1882, experienced western style in Japan and played an positive diplomatic activities with western nations. It could be guessed that those changes in the attitudes of the diplomats might have the relationship with the change of Chosun, which began a treaty of amity between western nations after 1882. Afterwards, Chosun seems to have decided to reform the system of traditional costume into the simplified one in 1884, proposed by the diplomats who experienced foreign culture abroad including Park Younghyo(朴泳孝) and the mutual agreement in Chosun Government.

• 한국산업정보학회논문지
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• 제19권2호
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• pp.85-91
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• 2014

본 연구는 MLS 데이터로부터 자동으로 철도 시설물들을 인식하여 시설물 간의 기하학적인 공간정보를 추출하는데 기여 하고자 한다. 본 연구에서 제안된 방법은 9개 주요 철도 시설물(노반, 레일, 철로, 수목, 플렛폼, 방음벽, 철주, 절연체, 고압선)들의 분류를 목적으로 하고 있다. 이를 위해 제안된 방법은 크게 두 단계로 나뉘어 진행된다. 첫 번째 단계에서는 포인트, 라인, 체적과 수직 프로파일 레벨에서 데이터의 맥락 특징(contextual feature)들이 추출된다. 두 번째 단계에서는 CRF(Conditional Random Field)가 맥락 분류자(contextual classifier)로 사용되어 각 데이터 포인트에 객체 정보가 할당되고 철도 시설물들이 분류된다. 사용된 CRF 모델은 다른 맥락 분류자 와는 달리 로컬지역에서 데이터들의 분류정보가 일관성을 유지하게 하는 장점이 있다. 제안된 방법의 성능은 commission과 omission 오류분석을 통해 입증되었다.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.246-249
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• 2011

SolarPACES is an international cooperative network bringing together teams of national exports from around the world to focus on the development and marketing of concentrating solar power systems (also known as solar thermal power systems). It is one of a number of collaborative programs, called Implementing Agreements, managed under the umbrella of the International Energy Agency to help find solutions to worldwide energy problems. Technology development is at the core of the work of SolarPACES. Member countries work together on activities aimed at solving the wide range of technical problems associated with commercialization of concentrating solar technology, including large-scale system tests and the development of advanced technologies, components, instrumentation, and systems analysis techniques. In addition to technology development, market development and building of awareness of the potential of concentrating solar technologies are key elements of the SolarPACES program The Implementing Agreement specifies broad "Tasks," or thematic areas of work SolarPACES currently has three ongoing tasks, focusing on concentrating solar electric power systems (Task I), solar chemistry research (Task II), and solar technology and applications (Task III). An Operating Agent, nominated by the ExCo, is responsible for overseeing the work of each task Each task maintains a detailed program of work that defines all task activities, including their objectives, participants, plans, and budgets. In addition to technical reports of the activities and their participants, accomplishments and progress are summarized in the SolarPACES annual report. Many SolarPACES activities involve close cooperation among member countries (either through sharing of task activities or, occasionally, cost-sharing), although some cooperation is limited to sharing of information and results with other participants. In this paper, structure, works, and members of SolarPACES and Korean activies in the SolarPACES are introduced.