• 대한기계학회논문집B
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• 제24권4호
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• pp.543-554
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• 2000

The engineering equations, which have been used in many engineering companies, were employed for the dynamic modelling part in order to develop the naturally circulated boiler simulator. The fuzzy algorithm, which is similar to the algorithm of making decision by the human being, was developed for the boiler simulator controller and its simulated variables were compared with those of classical PID simulations to verify the stability and the effectiveness of fuzzy controller. The simulator is for the naturally circulated boiler and the main components are the furnace, the drum, the super heater, and the economizer. The combustion and thermal radiation dominant equations were used within the furnace and the mass conservation and the energy rate balance equations were employed for the drum part. The heat transfer rates were calculated using the logarithmic mean temperature differences both for the super heater and for the economizer. The simulations are very useful to understand the boiler operations and the engineering design of the main components. The main program was developed under the PC window condition by linking the fuzzy controller to the main boiler program using the Visual C++ language. The various operational conditions such as the abrupt changes of load, the changes of water supply pipes and the diameter of drum were simulated.

• 한국정밀공학회지
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• 제32권5호
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• pp.455-461
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• 2015

This paper deals with an experimental verification of a temperature-dependent power loss model of a DC/DC converter in severe temperature conditions. The power loss of a DC/DC converter is obtained by summing the losses by the components constituting the converter including switching elements, diodes, inductors, and capacitors. MIL-STD-810F stipulates that any electronic devices must be operable in the temperature ranging from $-50^{\circ}C$ to $70^{\circ}C$. We summarized the temperature-dependent loss models for the converter components. A SEPIC-type converter is designed and built as a target. Using a constant-temperature chamber, a test rig is set up to measure the power loss of the converter. The experimental results confirm the validity of the loss model within 4.5% error. The model can be useful to predict the efficiency of the converter at the operating temperature, and to provide guidelines in order to improve the efficiency.

• 동아시아경상학회지
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• 제7권1호
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• pp.39-49
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• 2019

Purpose - The major aim of this article is to advance understanding of the relationship between market orientation and speed-to-market. Specifically, this study examines the different impacts of component of market orientation on commitment to R&D and speed-to-market and explores whether market uncertainty plays a role of moderating in speed-to-market for market-oriented firms. Research design, data, and methodology - This study collected a survey data from Korean exporting firms. The Final sample size was 196. The measure of market orientation was conceptualized with second order constructs. All items were measured on five-point scale. To confirm hypotheses, this study conducted a hierarchical regression. Results - As sub-constructs of market orientation, customer orientation, competitor orientation and interfunctional coordination foster speed-to-market, and the relationship between only customer orientation and speed-to-market might be weakened when the extent of market uncertainty is high. Conclusions - This study confirmed the relationship between market orientation and speed-to-market, with three components of market orientation respectively, and whether market uncertainty plays a role of moderating which weaken the link between market orientation and speed-to-market. It could be useful to take a component approach to the market orientation construct, because the roles of different market orientation components might vary, contingent on uncertainty in the environment.

• 수산해양기술연구
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• 제51권4호
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• pp.614-623
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• 2015

This study aims to estimate the Green-House-Gas emissions from domestic farmed flounder in the southern sea and Jeju-Do, where is mainly produced, by the assessment of energy consumptions and GHG emissions from domestic fish farms for establishing reduce standards of greenhouse gas from a sustainable perspective. It needs to analyze such GHG emission components as feed, electricity, fuel, fixed capital, fish respiration, and liquid oxygen in two locations by 4 stage running water type farm size of small, small and medium, large and medium, large scale. The result showed that the mean GHG emissions were $36.83kg{\cdot}CO_2/year$ in the southern sea and $24.33kg{\cdot}CO_2/year$ in Jeju-Do, respectively, in the stage of production per fish 1kg at 2 locations and farm size from domestic farmed flounders, and it will give to be useful for policy, planning, and regulation of aquaculture development with establishing GHG reduction standards.

• Journal of Mechanical Science and Technology
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• 제17권5호
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• pp.776-783
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• 2003

A low speed wind tunnel test was conducted for full-scale model of an unmanned aerial vehicle (UAV) in Korea Aerospace Research Institute (KARI) Low Speed Wind Tunnel(LSWT). The purpose of the presented paper is to illustrate the general aerodynamic and performance characteristics of the UAV that was designed and fabricated in KARI. Since the testing conditions were represented minor portions of the load-range of the external balance system, the repeatability tests were performed at various model configurations to confirm the reliability of measurements. Variations of drag-polar by adding model components such as tails, landing gear and test boom are shown, and longitudinal and lateral aerodynamic characteristics after changing control surfaces such as aileron, flap, elevator and rudder are also presented. To explore aerodynamic characteristics of an UAV with model components build-up and control surface deflections, lift curve slope, pitching moment variation with lift coefficients and drag-polar are examined. The discussed results might be useful to understand the general aerodynamic characteristics and drag pattern for the given UAV configuration.

• 한국정보통신학회논문지
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• 제9권3호
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• pp.561-569
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• 2005

현재 소프트웨어 개발의 주요한 패러다임인 객체지향 설계를 많은 시스템들이 채택하고 있으나, 화상 대화를 대상으로 한 연구들에서 본격적인 객체지향 설계의 적용은 그리 많지 않은 실정이다. 따라서 본 논문에서는 화상 대화 시스템에 대한 객체지향 설계를 위한 UML을 이용한 체계적인 아키텍처의 설계를 제시한다. 화상 대화 시스템에 대하여 체계적인 기능/비기능적 요구사항을 포착하고, '4+1 View Model'을 적용하여 객체지향 설계를 함으로써, 컴포넌트들은 재사용성을 담보하며, 이후 필요에 따라 컴포넌트들을 추가하여 시스템을 확장하는 것이 가능하다. 또한, 본 논문에서 설계한 화상 대화 애플리케이션의 컴포넌트들은 다른 여러 화상 대화 시스템에 활용 가능하며, 웹 환경에서의 서비스로도 확장될 것으로 기대된다.

• 한국진공학회지
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• 제17권1호
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• pp.1-8
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• 2008

포항가속기연구소 저장링에 설치된 방사광 차단용 진공부품에서 냉각수가 누설되었을 때의 진공도 분포, 압력 변화, 잔류 기체의 변화 등을 측정하여 그 특성을 분석하였다. 냉각수 누설 시에 압력 상승은 국부적으로 나타났으며 잔류 기체의 변화 양상은 누설 위치로부터 잔류기체 분석기까지 거리와 이온펌프 및 전자빔의 On/Off에 따라서 크게 달랐으며 특정 기체의 선택적 상승도 나타났다. 냉각수 누설의 발견은 전압변화 측정으로 가능하였으며 잔류기체 분석기로는 물분자를 직접 측정하기보다는 $CH_4$, CO, NO 등 특성 기체의 증가를 분석함으로 누설 여부를 판단할 수 있었다.

• The Journal of Asian Finance, Economics and Business
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• 제7권5호
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• pp.31-40
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• 2020

This study investigates whether other comprehensive income (OCI) reported in the statement of comprehensive income (one of the main financial statements after the adoption of K-IFRS) predicts a firm's future performance. Using the quarterly data of Korean listed companies, we examine the association between OCI estimates and future earnings. First of all, we find that OCI is positively associated with earnings in both 1- and 2-quarter ahead, supporting the predictive value of OCI. When we break down OCI into its individual components, our results suggest that the net unrealized gains/losses on available-for-sale (AFS) investment securities are positively associated with future earnings, while the other components (e.g., net unrealized gains/losses on valuation of cash flow hedge derivatives) present insignificant results. In addition, we investigate whether the reliability in OCI estimates enhances the predictive value of OCI to predict future performance. We find that the predictive ability of OCI, in particular the net unrealized gains/losses on available-for-sale (AFS) investment securities, becomes more pronounced when firms are audited by the Big 4 audit firms. Overall, our study suggests that information content embedded in OCI can provide decision-useful information that is helpful for the prediction of future firm performance.

• 재활간호학회지
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• 제18권2호
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• pp.153-164
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• 2015

Purpose: This study was conducted to develop a community capacity builded exercise maintenance program for frail elderly women. Methods: As a guideline to develop the exercise maintenance program, the intervention mapping framework, including needs assessment, setting program goals, selecting theory-informed intervention methods, producing program components, planning program implementation and evaluation, was used. Focus group interviews with public health nurses and frail elderly women were conducted for needs assessment. Intervention strategies and components were formulated based on community capacity theory. Results: The developed exercise maintenance program consisted of strategies focusing on leadership development, partnership construction, organization development, community systematization of dimension of community capacity. A exercise maintenance program using health leader, health contract, exercise pocketbook, rhythmic activity suiting song and self-help group was included. Conclusion: The intervention mapping method was found to be useful to develop theory-based valid and community capacity builded exercise maintenance strategies for frail elderly women.

• 응용통계연구
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• 제18권1호
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• pp.129-135
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• 2005

일변량 자료의 경우 대표관찰치는 사분위수 등에 기초하여 자료의 분포와 변이를 함축적으로 표현하기 위한 목적으로 사용되는 소수 개의 관찰치이다. Jones와 Rice(1992)는 다변량 자료에 대한 대표관찰치를 선택하기 위해 주성분분석에 근거한 방법을 제시한 바 있다. 이 연구에서는 주성분의 자기일치성을 이용하여 대표관찰치를 선택하고, 이를 표현하는 방안을 고찰한다. 기존의 방법에 의한 대표관찰치가 자료의 표본변이에 민감한 한편, 여기에서 제안되는 방법의 결과는 자기일치성을 가진다.