• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.10
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• pp.1623-1629
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• 2003

In this paper, the arc beam is considered as a moving disc heat source with a pseudo-Gaussian distribution of heat intensity. The solution for temperature distribution on welds is derived by using the image heat source method and the superposition method. It is general solution in that it can determine the temperature-rise distribution in and around the arc beam heat source, as well as the width and depth of the melt pool (MP) and the heat-affected zone (HAZ) in welding short lengths, where quasi-stationary conditions may not have been established. As a comparative study, the results of this analytical approach has been compared with that of the finite-element modeling. As a result, The theoretical analysis presented here has shown good consistency and is more time/cost-effective method compared with FEM.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.50.3-50.3
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• 2009

지구관측용 광학탑재체를 탑재한 저궤도위성은 내부부품보호를 위해 표면처리와 같은 수동적 기법과 히터동작과 같은 능동적 기법을 함께 사용을 한다. 내부열손실을 막기 위해 위성외부의 거의 모든 부분을 단열재(MLI)로 감싸게 되며, 각 단열재는 견고하게 고정이 된다. 광학탑재체는 구성품의 보호와 최적성능의 영상획득을 위해 다수의 히터가 장착되는데, 각 히터는 가열대상물의 온도를 실시간으로 측정하여 미리 설정된 On/Off 온도를 기준으로 제어가 된다. 궤도상에서 탑재체가 겪게 되는 다양한 궤도열환경 시나리오에 대한 열해석결과를 이용하여 히터의 위치, 용량 및 제어온도가 결정된다. 궤도상 운용 중, 위성을 보호하는 단열재 사이에 미세한 틈이 발생한 가상적인 상황을 가정하여, 탑재체 히터의 임무주기변화와 탑재체 운용에의 영향을 분석한다.

• Journal of Broadcast Engineering
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• v.23 no.6
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• pp.800-812
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• 2018

In this study, we reviewed recent trends for enhancing human cognitive accessibility to social VR platform. We also proposed a practical method to predict VR sickness and improve the cognitive accessibility. In doing so, we investigated subtle changes in human body sway unconsciously made before, during, and after being exposed to extreme VR experience. The scientific assumption that VR sickness would be correlated with the subtle changes in body sway was validated. We found that participants who showed sensitive changes in the body sway before VR experience, felt more severe VR sickness than others. The findings can be practically applied in predicting susceptibility to VR sickness prior to VR experiences.

• Journal of Digital Contents Society
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• v.19 no.4
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• pp.809-814
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• 2018

With the proliferation of cloud computing infrastructures, service providers are able to deploy services in on-demand manner. Recently, microservice architecture has been attracting attention in order to maximize the efficiency of resource expansion in cloud infrastructure. Instead of implementing all of the service functions in a single software, service providers can easily and autonomously implement the necessary services by interconnecting the necessary services through an efficiently designed application programming interface (API). Moreover service developer can freely choice programming languages and define software, and functional structures to meet their functional requirements. In this paper, we propose virtual infrastructure manager service based on microservice architecture and evaluates its performance in scalability perspective.

• Archives of design research
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• v.16 no.4
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• pp.25-36
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• 2003

The navigation in 3D virtual space is a procedure which must be carefully established in advance with understanding of a complicate perception process. Although current various desktop softwares are suppling developers with easier production circumstances in accordance with popularization era of interactive 3D media it is true that previous systematic conceptual study has been performed exclusively at specific institutions. Therefore, based upon the examples of virtual reality research reported by universities and companies core concepts giving the background for navigation realization and direct/indirect factors supporting substantial realization were analyzed and discussed in this paper.

• Journal of the Korean Society for information Management
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• v.25 no.3
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• pp.377-392
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• 2008

The need for overall assessment of economic effectiveness of library culture program has been suggested, as its importance continues to grow. Our study proposed a new assessment method by applying DM format and IBM format to contingent valuation method that has been used for analyzing the economic value of culture program. This study also illustrates the process through case analysis so that the public library can apply this model. It is meaningful that the study provides basic framework to evaluate the fair value of the public library by minimizing the bias that the contingent valuation method has.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5202-5207
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• 2011

A temperature control system is very important part in many industrial applications. Typical development procedures for temperature control system consist of several stages such as conceptual system design, construction of physical system, controller design based on the mathematical model for the system, and performance test. Since the mathematical model is usually obtained with the aid of system identification technique based on repeated experiments after construction of the physical system, the above procedures require very large amount of time and cost. It takes also large amount of time in the controller design and performance test procedures. In this paper, a virtual development scheme, which can predict the performance of the temperature control system prior to construction of physical system, for rapid validation of the initial system design is proposed. The effectiveness of the proposed scheme is shown by using SISO (Single Input Single Output) example.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.454-456
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• 2004

다양한 환경과 급변하는 시장의 적시성 요구사항(time-to-market)을 반영하기 위해서는 재구성 가능한 컴포넌트 기법을 통한 개발이 소프트웨어 공학 측면에서 많이 연구되어 왔다. 하지만 이러한 컴포넌트 기법은 여러 장정에도 불구하고. 성능 저하라는 측면 하나만으로 시스템 잊 플랫폼 구축분야에서 소외당해 온 것이 사실이다 그러나 최근 유비쿼터스 및 내장형 시스템이 대두됨에 따라 이러한 판도에 많은 변화가 예상되고 있다. 이는 현재 활발히 연구.개발되고 있는 유비쿼터스 밀 내장형 시스템 기반의 어플리케이션은 획일화되지 않은 환경 하에 있는 물리적 환경의 특성상 일정한 플랫폼의 형태에서 벗어나 매우 다양한 환경에 융통성 있게 적용되어야 하고. 이에 상위 프로그램에 투명성을 제공할 수 있는 플랫폼이 필요로 하게 되었다 따라서 본 논문에서는 내장형 시스템 밀 유비쿼터스 환경에 적합한 미들웨어 플랫폼을 구성하기 위해. 재구성과 융통성을 제공하기 위한 컴포넌트기반 소프트웨어 개발 방법을 적용한 새로운 자바 가상머신 설계기법을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.867-870
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• 2010

여러 장치들과 연동하여서 동작하는 네트워크 시스템 개발 시, 회귀 테스트는 전체 시스템의 안정성을 보장하기 위한 가장 필요한 테스트중의 하나이다. 그러나, 서비스가 되고 있거나 연동을 위한 추가적인 장비가 필요할 경우 테스트의 제약을 받게 된다. 본 논문에서는 자동 회귀 테스트를 위한 가상 네트워크 망을 제공하는 시뮬레이터를 디자인 한다. 또한, 시뮬레이터를 효율적으로 관리 및 동작하기 위한 UI 환경을 제안한다. 오픈 소스를 기반으로 제작된 본 시나리오의 관리 툴은 회귀 테스트의 자동화와 시나리오의 생성 및 배포가 가능하며 여러 프로토콜을 통합하여 사용할 수 있는 환경과 검증 코드를 제공한다. 이로 인해 네트워크 시스템 상의 소프트웨어에 대해 기능 및 회귀 테스트가 가능해 질것이고 결과적으로 프로그램의 개발 시간 단축과 유지보수에 탁월한 환경을 제공받게 될 것이다.

• Journal of Korean Association for Spatial Structures
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• v.10 no.4
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• pp.85-92
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• 2010

Use of concrete has undoubtedly become widespread in construction and civil engineering. Sensors are used to add functional characteristics to concrete. Self-diagnosis concrete is also being developed. The thermal protector used in the study is a sensor using the linear expansion and cubical expansion of metal. The LED(Light Emitting Diode) is a phototransistor type, and to secure high-sensitivity light, the prices of these sensors are low. Rising temperatures of concrete elements can be predicted from LED of the external virtual beam due to operation of thermal protector sensors of concrete beam caused by fire load on the concrete specimen. In this study, the development of fire-diagnosis concrete using composite sensors are the fundamental study for damage detection using simply measurements.