• International Journal of Air-Conditioning and Refrigeration
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• 제14권1호
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• pp.1-6
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• 2006

For the purpose of processing weather data for air conditioning equipment de sign in Busan area Korea, this study collected weather observations made by Busan weather Administration from 1970 to 2003, and then established external conditions for heating and air-conditioning design. For changes of temperature in external conditions for design, the highest temperature had little changed, whereas the lowest had been on the rise as the years went by through the 1970s, 1980s, 1990s, and 2000s, but insolation has a little lessened. Absolute humidity does not show a significant change but an incessant rise.

• Steel and Composite Structures
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• 제8권3호
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• pp.201-216
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• 2008

The Eurocode system provides limited information regarding the structural fire design of external steel structures. Eurocode 1 provides thermal action for external member but only in steady-state conditions. On the other hand, Eurocode 3 provides a methodology to determine heat transfer to external steelwork, but there is no distinction in cross section shapes and, in addition, the calculated temperature distribution is assumed to be uniform in the cross section. This paper presents the results of a research carried out to develop a new transient heat transfer model for external steel elements to improve the current approach of the Eurocodes. This research was carried out as part of the project EXFIRE "Development of design rules for the fire behaviour of external steel structures", funded by the European Research Programme of the Research Fund for Coal and Steel (RFCS).

• 한국항공우주학회지
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• 제50권5호
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• pp.297-308
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• 2022

극초음속 영역에서 운용되는 대부분의 극초음속 공기흡입(Air-breathing) 비행체들에 스크램제트 엔진이 탑재되고 있다. 스크램제트(Scramjet) 엔진에서는 일반적인 가스터빈 엔진의 압축기 역할을 흡입구에서 발생하는 충격파가 대신 수행하기 때문에 충격파에 의한 전압력 손실이 매우 중요하게 여겨진다. 본 연구에서는 전압력 손실을 최소화하기 위해 등엔트로피 압축면을 적용한 외부 압축형 흡입구의 설계법을 제시하고, 동일한 조건의 Busemann 흡입구와 3개의 cone 각도를 가지는 외부 압축형 흡입구를 설계하였다. 이후 전산해석을 통해 비설계 조건에 대한 성능 특성을 비교하였다. 각 흡입구 형상은 3단 외부 압축형 흡입구의 길이에 맞춰 truncation을 진행하였으며, 경계층 보정을 수행하였다. 등엔트로피 외부 압축형 흡입구는 3단 외부 압축형 흡입구에 비해 설계점에서는 우수한 성능을 보였으나 일부 비설계 조건에서는 3단 외부 압축형보다 성능이 저하되는 현상이 발생하였다.

• 복식
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• 제63권3호
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• pp.17-32
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• 2013

This study examined the visual elements of the Trompe l'oeil design and the combination conditions of each element in order to deduce the form generation diagrams of Trompe l'oeil fashion design. The following is what the study found: First, Trompe l'oeil fashion design can be divided into two based on its subject: 'the combination of internal elements of dress' and 'the combination of external elements of dress'. Looking at the visual components of each type, depending on the subject, 'the combination of internal elements of dress' design was achieved by combining internal dress elements: including textile, detail, item, accessory, layering, etc.. In case of 'the combination of external elements of dress' design, the object of Trompe l'oeil was expanded in scope to environment, which includes the actions of a wearer. Second, as for Trompe l'oeil fashion design through the combination of external dress elements, the condition to combined visual components of the work in the process of creation was related to 'the popularity of object', 'the similarity of shapes and sizes', and 'the probability of location'. Third, deriving a form generation diagrams of Trompe l'oeil fashion design was very effective in delineating specific relationships and conditions, directions among elements combined in fashion design.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 심포지엄 논문집 정보 및 제어부문
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• pp.207-208
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• 2008

This paper presents a robust state observer design for a class of Lipschitz nonlinear systems with time delay and external disturbance. A sufficient conditions on the existence of the proposed observer are characterized by linear matrix inequalities. It is also shown that the proposed observer design can reduce the effect on the estimation error of external disturbance up to the prescribed level in spite of the existence of time delay. Finally, a numerical example is provided to verify the proposed design method.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 춘계학술대회논문집
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• pp.67-70
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• 2000

The tool life is not long enough under sever forming condition in warm forging. The tool life is affected by wear heat fatigue plastic deformation and so on. Especially wear is one of the most serious factors for tool life. To increase tool life we should consider various factors like processing design die design die materials lubrication and cooling system This study design to obtain the steady state temperature of die by FEM analysis under several conditions of cooling. There are four cooling conditions in this study no cooling internal cooling external cooling and both internal and external cooling. With above obtained temperatures tool life is predicted using Archard's model that is considered softening of die. The effect of internal cooling system is better than that of externally cooled die. To predict the die life the steady state temperature is calculated by using mean temperature of die. Considering only wear the die life much longer as the cooling effect is bigger. The more accurate die life will be predicted if we consider heat crack as well as wear.

• 제어로봇시스템학회논문지
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• 제14권8호
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• pp.837-841
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• 2008

This paper presents a robust reduced order state observer for a class of Lipschitz nonlinear systems with external disturbance. Sufficient conditions on the existence of the proposed observer are characterized by linear matrix inequalities. It is also shown that the proposed observer design can reduce the effect on the estimation error of external disturbance up to the prescribed level. Finally, a numerical example is provided to verify the proposed design method.

• 한국의류산업학회지
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• 제20권2호
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• pp.167-176
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• 2018

In this study, an eye-tracking program that can confirm a design cognition process was developed for the purpose of presenting strategic methods to create fashion images, and the program was used to identify what effects fashion models' external characteristics have on the cognition of design. The data for analysis were collected through an eyemovement tracking experiment and a survey, with the focus on the research problem that differences in models' external uniformity will lead to differences in the eye movement for perceiving models and design as well as the image sensibility. The results of the analysis are as follows. First, it was confirmed that the uniformity of model types and the simplicity/complexity of design led to differences in the eye movement directed at design and models and the gaze ratio. Consequently, it is deemed that models should be selected in consideration of the characteristics of design and the intention of planning when creating fashion images. Second, it was found that in terms of the cognition of design, external conditions of models affect design sensibility. A change in models led to a subtle difference in sensibility cognition even when the design condition did not change. Thus, not only the design but also model attributes are factors that should be considered important in fashion planning.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.480-485
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• 2009

Offshore wind energy is gaining more attention. Ensuring proper design of offshore wind turbines and wind farms require knowledge of the external conditions in which the turbines and associated facilities are to operate. In this work, a three-bladed 5MW upwind wind turbine, which is supported by the monopile foundation, is studied by use of fully coupled aero-hydro-servo-elastic commercial simulation tool, 'GH-Bladed'$^{(R)}$. Specification of the structures are chosen from the OC3 (Offshore Code Comparison Collaboration) under "IEA Wind Annex XXIII-subtask2". The primary external conditions due to wind and waves are simulated. Design Load case 5.2 is investigated in this work. The steady state power curve and power production loads are evaluated. Comparison between different codes is made.

• 설비공학논문집
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• 제29권11호
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• pp.570-579
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• 2017

In this study, we examined the multi-stage piston-type air compressors typically used in a railroad vehicle, and the heat transfer efficiency was analyzed according to the design conditions of the heat exchanger (a compressor component module for cooling the compressed high temperature air). For the fin-tube heat exchanger used in the most air compressors, numerical analysis was performed to analyze heat transfer by defining the various rectangle tube sizes and the number of fin-per-unit area as design variables under the same flow rate of compressed air. Also, this analysis compared the temperature of the compressed air. Regarding environmental conditions for analysis, the flow rate of the external cooling air was measured and the mean value of the values was applied. And a "turbulence model" was considered in both the external flow of the cooling air and the internal flow inside the tube. From the results of analysis, it was found that the change of the aspect ratio value of the tube greatly influences the heat transfer efficiency of the compressed air, and influences if the fin density is relatively small. As a result, the optimum design specifications of the heat exchanger for air compressors were confirmed based on the analysis of the heat transfer efficiency, according to the design conditions of fin and tube by the operating temperature range of the compressed air.