• 한국생산제조학회지
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• 제19권6호
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• pp.883-888
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• 2010

This study have goal with conceptual design for Offshore Structures of high pressure control valve for localization. Ball valve for development accomplished with flow analysis based on provision of ANSI B16.34, ANSI B16.10, ANSI B16.25 In order to localize the Offshore Structures high pressure control valve. Numerical simulation using CFD (Computational Fluid Dynamic) in order to predict a mass flow rate and a flow coefficient form flow dynamic point of view. The working fluid assumed the glycerin (C3H8O3). The valve inlet and outlet setup a pressure boundary condition. The outlet pressure was fixed by atmospheric pressure and calculated until increasing 1bar to 10bar. CFD analysis used STAR-CCM+ which is commercial code and Governing equations were calculated by moving mesh which is rotated 90 degrees when ball valve operated opening and closing in 1 degree interval. The result shows change of mass flow rate according to opening and closing angle of valve, Flow decrease observed open valve that equal percentage flow paten which is general inclination of ball valve. Relation with flow and flow coefficient can not be proportional according to inlet pressure when compare with mass flow rate. Because flow coefficient have influence in flow and pressure difference. Namely, flow can be change even if it has same Cv value. The structural analysis used ANSYS which is a commercial code. Stress analysis result of internal pressure in valve showed lower than yield strength. This is expect to need more detail design and verification for stem and seat structure.

• 산업경영시스템학회지
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• 제40권2호
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• pp.41-50
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• 2017

The purpose of this paper is to improve the service tree analysis introduced recently by Geum et al. [15]. Service tree analysis structures the service based on the customer participation perspective and provides a qualitative analysis method categorizing the service elements on the basis of its impact to top service. This paper attempts to apply the concept of reliability importance to the service tree analysis as a perspective of quantitative analysis, which is considered little in Geum et al. [15]. Reliability importance is a measure of the structural impact of the components that make up the system on the system lifetime in reliability engineering field and often used in fault tree analysis. We transform the reliability importance into service importance in accordance with service tree analysis, so that the influence of service elements on the service can be judged and compared. The service importance is defined as the amount of change of the service according to the change of the service element, therefore, it can be utilized as an index for determining a service element for service improvement. In addition, as an index for paired service elements, the relationship between the two service components can be measured by joint service importance. This paper introduces conceptual changes in the process of applying reliability importance to service analysis, and shows how to use the service importance for identifying the priority of service element for the final service and improving customer satisfaction through an example. By using the service importance and joint service importance in service tree analysis, it is possible to make efficient decision making in the process of determining the service elements for analyzing and improving the service.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1195-1200
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• 2008

This study have goal with conceptual design for Offshore Structures of high pressure control valve for localization. Ball valve for development accomplished with flow analysis based on provision of ANSI B16.34, ANSI B16.10, ANSI B16.25 In order to localize the Offshore Structures high pressure control valve. Numerical simulation using CFD(Computational Fluid Dynamic) in order to predict a mass flow rate and a flow coefficient form flow dynamic point of view. The working fluid assumed the glycerin($C_3H_8O_3$). The valve inlet and outlet setup a pressure boundary condition. The outlet pressure was fixed by atmospheric pressure and calculated until increasing 1bar to 10bar. CFD analysis used STAR-CCM+ which is commercial code and Governing equations were calculated by moving mesh which is rotated 90 degrees when ball valve operated opening and closing in 1 degree interval. The result shows change of mass flow rate according to opening and closing angle of valve. Flow decrease observed open valve that equal percentage flow paten which is general inclination of ball valve. Relation with flow and flow coefficient can not be proportional according to inlet pressure when compare with mass flow rate. Because flow coefficient have influence in flow and pressure difference. Namely, flow can be change even if it has same Cv value. The structural analysis used ANSYS which is a commercial code. Stress analysis result of internal pressure in valve showed lower than yield strength. This is expect to need more detail design and verification for stem and seat structure.

• 대한수학교육학회지:학교수학
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• 제16권2호
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• pp.317-334
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• 2014

이 연구는 예비교사들을 대상으로 테일러급수와 그 수렴에 대한 이해 실태를 살펴보았고 그 결과로 얻어진 취약점을 보완하고자 GeoGebra를 이용하여 실험적 맥락에서 테일러급수의 수렴 개념에 대한 교수 방안을 모색하였다. 예비교사들은 형식적 측면에서 테일러급수를 구하고 수렴 반경을 계산하는 것에는 익숙했지만 개념적이고 과정적 요소엔 취약하였으며 테일러급수를 다루는 시각적이고 역동적 경험을 갖고 있지 못했다. 특히 부분합의 개념으로 테일러다항식들의 수렴과 원함수간의 관계가 잘 정립되어 있지 않았다. 이에 GeoGebra를 도구로 활용하여 시각적이고 직관적 측면에서 테일러다항식의 차수와 중심이 테일러급수의 수렴에 미치는 영향을 중심으로 교수실험을 하였다. 이 연구의 결과는 예비중등 수학교사들이 무한급수와 테일러급수에 대한 교수 내용적 지식을 높이고 유연한 지식을 가지는 데 공학을 활용한 교수법이 도움이 될 수 있음을 보여주었다.

• 영재교육연구
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• 제23권6호
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• pp.1099-1115
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• 2013

지식의 생성 주체로서 집단지성이 주목받고 있다. 집단지성으로 문제를 해결하기 위해서는 협업이 필요한데 협업을 위한 기본 조건은 정보의 공유이다. 이 연구에서는 4명의 과학영재 학생들을 대상으로 불일치 상황을 제시하고 이를 과학적으로 설명하도록 요구한 후 그들의 문제해결과정을 분석함으로써 과학영재들이 협업적 문제해결과정에서 무엇을 공유하는지를 알아보았다. 연구 결과, 과학영재들은 문제발견과정에서 전제와 문제를 공유하였고, 가설 생성과정에서는 문제해결의 목표와 이 목표에 도달할 수 있는 수단을 공유하여 가설을 생성하기 위한 조작자 인출에 이용하였다. 생성된 가설이 평가되는 과정에서는 해결방법의 평가기준으로서 제약조건과, 이를 이용한 평가의 결과를 공유하였다. 이는 집단이 생각의 공유를 통해 스스로 지식을 창출하고 자신들의 개념을 변화시켜 나가는 것을 의미한다. 이러한 문제해결과정을 통한 자발적인 개념변화는 영재교육에 시사점을 제공한다.

• 농촌의학ㆍ지역보건
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• 제48권1호
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• pp.13-27
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• 2023

Objectives: The purpose of this study is to investigate changes in public health-related perceptions of residents of Gangwon province after the outbreak of Coronavirus disease-19(COVID-19) of the public. Methods: We performed paired T-test analysis to measure the change in public health-related perceptions before and after COVID-19. We also utilized generalized estimating equations to identify demographic factors correlated with public health-related perceptions. Results: The public perceived public health as 'All citizens can use medical care and protect/promote health.' The concept was the most popular, from 94.3% in 2019 to 95.5% in 2020. In addition, after COVID-19, residents of Gangwon province's satisfaction with medical services increased, but the overall level was not high. Among the eight essential healthcare needs after COVID-19, cardiovascular disease and injury services have emerged as preferred services. However, by sociodemographic factors, distinctive responses were detected. Conclusions: Through COVID-19, Gangwon residents' awareness of the public's health rights has increased. Those living in vulnerable areas or with unmet medical care, supported strengthening public health care. In addition, although medical satisfaction has increased, it is not satisfied, so listening to the voices of the population group with low satisfaction is essential. Lastly, since the necessity of essential health care may change due to specific events, the local government needs to plan health projects reflecting the needs of residents. Therefore, when designing the public health care strategy in Gangwon province, the local government should consider not only political factors but also environmental factors, demographic and conceptual factors.

• 한국전통조경학회지
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• 제30권2호
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• pp.119-129
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• 2012

용도서와 귀문원은 홍만선이 저술한 "산림경제" "복거(卜居)" 편에 실려 있다. 이 글은 하도(河圖)와 낙서(洛書)의 원리를 적용한 독특한 정원 구상안으로, 실제 조영된 바 없는 상상 속의 정원이다. 여기에는 두 정원의 모습이 구체적으로 묘사되어 있으나, 상수학에 대한 이해가 없이는 여기에 내재된 의미를 파악할 수 없다. 따라서 본 연구의 목적은 이 기록을 고찰함으로써 정원도해에 담긴 의미와 조경사적 의의를 밝히는데 있다. 연구의 목적을 달성하기 위해 이 글의 배경이 되는 저작 및 편찬자, 상수학의 개요를 살펴보았다. 또 하도와 낙서에 담긴 생수(生數)와 성수(成數), 음양, 사상, 팔괘도 등의 원리를 고찰하였다. 이러한 연구 과정을 거친 본 연구의 결과를 요약하면 다음과 같다. 첫째, 하도와 낙서는 우주변화의 원리 등 상수철학의 기본 명제들을 포괄적으로 추상화한 개념적 정의(conceptual definition)라 할 수 있는데, 용도서와 귀문원은 이를 정원구성 원리로 적용하여 거기에 담긴 의미를 구체적으로 경험하고, 반복 가능한 방식으로 설명할 수 있도록 한 조작적 정의(operational definition)라 할 수 있다. 이러한 시도는 중국에서도 전례가 없는 독특한 사례이다. 둘째, 하도와 낙서에 내재된 의미에 대한 조작적 정의를 구체화하기 위한 수단으로서 정원이라는 생활공간이 선정되었고, 하도와 낙서의 방위개념과 위치와 수 등을 재현하는 소품으로 태극정과 십자각, 돈대, 우물, 연못 등과 함께 각종 수목이 사용되었다. 셋째, 용도서와 귀문원은 각기 하도와 낙서가 표상하고 있는 선천과 후천, 체와 용의 관계를 주 모티브로 하고있다. 즉, 용도서는 하도가 표방하는 우주생성의 원리, 정적이며 조화, 질서, 상생의 모습을 상징하기 위하여 '십장청'이라는 상록수만을 식재하도록 구상하였다. 귀문원에는 낙서가 표방하는 후천의 변화 즉, 동적이며 부조화 무질서, 상극, 변화를 표현하기 위해 화목과 과목을 자유롭게 식재하도록 하였다. 이러한 식재효과를 통해 구현하고자한 두 정원의 시각적 이미지(image)의 차별성은 용도서에는 '청상함', 귀문원은 '화려함'으로 함축된다. 하도와 낙서가 바탕이 된 상수학은 고대 이래로 오랜 기간에 걸쳐 다양한 학파와 여러 학자의 지혜가 축적된 동양의 독특한 사고 체계이다. 따라서 그 개념과 이론이 심오하고 방대하며 해석의 관점도 다양하다. 이러한 맥락에서 동양철학의 제반 개념들에 대해 보다 심층적이고 다양한 관점에서 고찰하지 못한 점은 본 연구의 한계이다. 추후 연구과제는 전통정원에 내재된 상수학 등 동양사상에 대한 보다 실증적인 연구가 필요할 것이다.

• 한국실내디자인학회논문집
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• 제21호
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• pp.10-16
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• 1999

Mathematics is considered to the beginning of designing thinking because of the sense of logical order system. In this study, it was regarded the mathematics as the logic and the measurement of design system. as is often the case in history, mathematics, it is regard as conceptual model of architectural though, as aesthetic proportional measure and the mirror of thought. The direction of this study is rather multi-sided approaching to the spatial concept than one-sided plane. It is multi-acceptable way to apply mathematical principle to the pace and to be a flexible one. And boundary of interpretation of the flexibility means potential use-ability, and the strictly meaning of flexibility means that the acception of the various Secession and the Change of space. And the various interpretation of the flexibility only can expressed in the relation of opposite concept: the assembly and the disassembly, the expand and the decease, the open and the close and the construct and the de-construct. Mathematics provide the resonable way in architectural thinking and endow the order as logical organizatiov. Regarding these facts, this research is for making it possible to consider the expression property of interior space combination as the way of understanding the accepting of the changes of the times with the mathematical induction, using the rational method like the mathematical arrangement organizatiov.

• 환경영향평가
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• 제17권1호
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• pp.67-79
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• 2008

Global warming, which is one of the most serious challenges, has been the subject of intense debate and concern for many scientists, policy-makers, and citizens for at least the past decade. To protect the health and economic well-being of current and future generations, we must reduce our emissions like carbon dioxide. Alternatives to achieve an energy future without serious global warming are to change to clean and renewable sources of energy like the wind, the sun lights, rivers, the biomass, hydrogen, and oceans. To identify some of the key and new environmental impacts associated with renewable energy and hydrogen energy, we set up the new conceptual methodology. Specifically, new identified environmental and health impacts are related with the usage of hydrogen energy. When comparing with fossil fuel, the renewable energies can reduce the release of carbon dioxide when they are used except hydrogen produced from fossil fuel. However, all renewable energy technologies are not appropriate to all applications or locations. Our results suggest that all of alternatives to replace fossil fuel can release the several global and local impacts although they seems to be smaller than the impacts from fossil fuel. Therefore, the quantitative and detail analysis to assess environmental impacts of the alternative energies might be useful to make our decision for the future energy against the global warming.

• 대한조선학회논문집
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• 제49권1호
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• pp.1-5
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• 2012

Recently, with increasing container ships' volume continuously, the conceptual design "Smart Harbor" of newly logistics processing system has been suggested. It is necessary to estimate resistance and horsepower for the selection of an appropriate propulsor at the initial design stage of Smart Harbor. In this study, CFD and the circulating water channel of the University of Ulsan are employed for estimating the resistance of the Smart Harbor Crane Ship with 1/100 scaled model. Two turbulent models are used. One is realizable k-${\varepsilon}$and the other is Reynolds stress turbulence model. In addition, the effects of the change in y+ and the number of meshes are considered during analysing.