• 한국산업정보학회논문지
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• 제20권4호
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• pp.75-87
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• 2015

중복시스템의 일반적인 구조는 기능을 수행하는 주요부품과 주요부품이 고장 나는 경우에 그 기능을 대신 수행하는 대기부품으로 구성되어 있다. 본 연구에서는 하나의 대기부품이 여러 개의 주요부품의 기능을 동시에 대신 수행할 수 있는 다기능 대기부품을 갖는 병렬시스템을 고려한다. 이 시스템을 구성하고 있는 모든 부품들은 작동상태와 고장상태만 갖는 반면 시스템은 구성 부품들의 상태에 따라 다중 상태를 갖는 것을 가정한다. 이러한 중복구조는 항공기와 같이 시스템의 중량이 중요한 요소인 시스템에서 많이 채택되고 있는 구조이다. 본 연구에서는 이와 같은 중복시스템의 신뢰도를 평가하기 위한 새로운 신뢰도모델링 기법을 제안하고 부품들이 상수고장률을 갖는 경우 마코프 분석 방법을 적용하여 시스템의 신뢰도를 구한다. 또한 본 연구에서 고려하고 있는 시스템과 기존에 이미 알려진 병렬시스템과 중복구조를 갖는 병렬시스템의 신뢰도를 비교하여 다기능 대기부품의 효과를 분석한다.

• 한국항공우주학회지
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• 제40권2호
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• pp.157-164
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• 2012

다기능 구조체는 전자장비, 열제어 부품, 우주복사 차폐물 및 지지구조물이 하나의 시스템으로 통합된 구조적 결합체로써, 위성 및 행성탐사선 모듈의 소형화/경량화를 달성하여 경제성을 획기적으로 향상시킬 수 있는 매우 중요한 첨단 모듈이다. 본 연구에서는 구조적인 강도를 고려하여 설계된 다기능 구조체의 6가지 형상에 대하여 방열성능을 수치해석적인 방법으로 검토하였다. 다기능 구조체의 rib 형상이 방열판 내 전열효과에 미치는 영향은 열전도 측면만을 고려하는 것은 의미가 없으며, 구조적인 강성, 제작의 난점, 무게 등을 모두 고려하여야 하고, 전열 측면에서는 rib의 형상보다 면재 외부층의 두께와 무게에 대한 trade-off를 통하여 최적화하는 것이 일반적으로 유효하다고 판단된다.

• 산업경영시스템학회지
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• 제40권3호
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• pp.138-147
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• 2017

As the functions and structure of the system are complicated and elaborated, various types of structures are emerging to increase reliability in order to cope with a system requiring higher reliability. Among these, standby systems with standby components for each major component are mainly used in aircraft or power plants requiring high reliability. In this study, we consider a standby system with a multi-functional standby component in which one standby component simultaneously performs the functions of several major components. The structure of a parallel system with multifunctional standby components can also be seen in real aircraft hydraulic pump systems and is very efficient in terms of weight, space, and cost as compared to a basic standby system. All components of the system have complete operation, complete failure, only two states, and the system has multiple states depending on the state of the component. At this time, the multi-functional standby component is assumed to be in a non-operating standby state (Cold Standby) when the main component fails. In addition, the failure rate of each part follows the Weibull distribution which can be expressed as increasing type, constant type, and decreasing type according to the shape parameter. If the Weibull distribution is used, it can be applied to various environments in a realistic manner compared to the exponential distribution that can be reflected only when the failure rate is constant. In this paper, Markov chain analysis method is applied to evaluate the reliability of multi-functional multi-state standby system. In order to verify the validity of the reliability, a graph was generated by applying arbitrary shape parameters and scale parameter values through Excel. In order to analyze the effect of multi-functional multi-state standby system using Weibull distribution, we compared the reliability based on the most basic parallel system and the standby system.

• 한국생산제조학회지
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• 제25권5호
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• pp.313-320
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• 2016

The need for high-strength, multi-axis, and multi-functional machine tools has recently increased because of part complexity and workpiece strength. However, most of the machine tool manufacturers rely on experience for a detailed design because of the shortcomings in the existing design technology. This study uses a topology optimization method to more effectively design a large multi-functional machine tool considering static stiffness. The ram, saddle, and column parts are important structures in a machine tool. Hence, they are selected for the finite element method analysis. Based on this analysis, the optimized internal rib structure for those parts is designed for desirable rigidity and weight. This structure could possibly provide the required design technology for machine tool manufacturers.

• 항공우주기술
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• 제8권2호
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• pp.68-74
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• 2009

지구 관측용 광학탑재체를 포함하는 정지궤도 복합위성에는 관측 대상인 지구의 기준위치 정보를 제공하기 위해 적외선 지구센서가 장착된다. 정지궤도상에서 지구센서와 관측 탑재체사이의 지향차는 그 크기가 작더라도 관측 영상의 품질에 심각한 영향을 미칠 가능성이 있다. 따라서 이러한 지향차를 줄이기 위해 궤도상에서 기하학적 안정성을 보장할 수 있는 지지구조물이 적용되었다. 본 논문에서는 통신해양기상위성에서 지구센서 장착을 위해 사용된 지지구조물에 대한 설계 측면의 타당성을 제시한다. 이를 위해 설계 전반의 내용을 기술하고, 설계과정에서 고려된 안정성 측면의 제반 사항과 강성과 강도 등의 요구조건에 대한 부합 여부를 살펴볼 것이다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.166-169
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• 1995

An intelligent system which is an integration of multi-functional instrumentation (MFI) and a neural network is discussed. According to some experiments of temperature and wind velocity it is clear that this system can learn the data structure of two parameters above. So it makes good performances for estimations of non-sample data.

• 한국의류학회지
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• 제37권3호
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• pp.247-259
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• 2013

This study conceptually approaches and clearly compares the similarities and differences of fashion and architecture through a focus on their correlations. This study identifies the conceptual definitions of functional minimalism by an examination of function that represents the largest similarity between architecture and fashion. This study classifies the nature of functional minimalism and studies cases for each architectural classification in the areas of: the simplicity of a structure, unitarity pursuit of economic value, repeatability in an efficiency unit, reducibility stressing property, and multi-functional spatiality. The characteristics of functional minimalism fashion are distinguish as: simplicity in a structure that highlight structural lines in non-decorated design, unitarity pursuit of economic value represented in united process and pattern for its economic effect, repeatability in an efficiency unit represented through the repeated decoration of a functional unit, reducibility stressing a property that emphasizes property with a dominant design element through a highlight of the characteristics of materials and multi-functional spatiality that represents variability in clothes through an expansion of limited spatial function. This study approaches each discipline with a clear understanding of the differences between the two and suggests standards for a comparative study of architecture and fashion.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.171-172
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• 2015

$Ni-W-Si_3N_4$ alloy composite coatings were prepared by pulse electro-deposition method using nickel sulfate bath with different contents of tungsten source, $Na_2WO_4.2H_2O$, and dispersed $Si_3N_4$ nano-particles. The structure and micro-structure of coatings was separately analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). Results indicated that nano $Si_3N_4$ and W content in alloy had remarkable effect on micro-structure, micro-hardness and scratch resistant properties. Tungsten content in Ni-W and $Ni-W-Si_3N_4$ alloy ranged from 7 to 14 at.%. Scratch test results suggest that as compared to Ni-W only, $Ni-W-Si_3N_4$ prepared from Ni/W molar ratio of 1:1.5 dispersed with 20 g/L $Si_3N_4$ has shown the best result among different samples.

• 한국가구학회지
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• 제26권4호
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• pp.356-363
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• 2015

Recently, the increase of single households are remarkable in Korean society due to various social and economic reasons such as aging and changes in values, and it is expected to bring many changes to social and economic structures and residential spaces. Increase of single households is a result of complex economic, cultural and social factors. It is because as the individual's financial independence increases due to elevated income and education level, the age of marriage is going up and the individualism, which values the individual's value rather than custom, is spreading. It is expected to accelerate further in connection with the changes in structure of population, such as a low birth rate and aging. As the number of single households is increasing, the development and marketing for single household products are actively growing. With the increase in consumption demand and need of growing single households, the multi-functional system furniture that can be efficiently and conveniently used in small spaces are needed, but the furniture manufactured in Korean companies are designed for regular housing and is not suitable for single households. Therefore, the aim of this study is to develop multi-functional system furniture can be freely used in the housing structure of single household and small spaces.

• 미생물학회지
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• 제29권4호
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• pp.209-214
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• 1991

The PRD1 DNA polymerase is a small multi-functional enzyme containing conserved amino acid sequences shared by family B DNA polymerases. Thus the PRD1 DNA polymerase provides an useful model system with which to study structure-functional relationships of DNA polymerase molecules. In order to investigate the functional and structural roles of the highly conserved amino acid sequences, we have introduced three mutations into a conserved amino acid of the PRD1 DNA polymerase. Genetic complememtation study indicated that each mutation inactivated DNA polymerase catalytic activity.