• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.10
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• pp.559-563
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• 2009

Performance of refrigerant oil at the thrust-bearing and at the journal-bearing of a scroll compressor is a significant factor. This paper presents the friction and anti-wear characteristics of nano oil with a mixture of a refrigerant oil and carbon nano particles. The characteristics of friction and anti-wear using nano-oil is evaluated using the disk on disk tester for measuring friction surface temperature and the coefficient of friction. The average friction coefficient of nano-oil was reduced by 60% compared to raw oil under 600 N and 1,000 rpm. It is believed that the interaction of nano particles between surfaces can be improved the lubrication in the friction surfaces. Worn surfaces of frictional specimen were also investigated by the optical and atomic force microscopy. Conclusively, it is expected that wear and friction coefficient of compressor can be reduced by alignment applying nano-oil as refrigerant oil.

• The KIPS Transactions:PartB
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• v.8B no.3
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• pp.283-287
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• 2001

컴퓨터를 이용한 협동작업은 공간적으로 분산되어 있는 여러 작업자들이 동기적 EH는 비동기적으로 협력할 수 있게 함으로써 보다 신속하고 정확하게 작업을 진행할 수 있게 한다. 최근의 협동작업 분야의 급속한 발전은 이제 더 이상 웹 상에서의 협동작업 도구를 메일, 채팅, 화이트보드, 화상회의 등에 한정하지 않고 웹 응용 프로그램들을 협동작업 도구에 포함시키기에 이르렀다. 본 논문에서는 공간적으로 분산되어 있는 여러 작업자들이 상용 웹 브라우저를 이용하여 웹 문서와 웹 데이터베이스 내용을 공유함으로써 보다 효율적인 협동작업을 할 수 있는 시스템을 소개한다. 본 논문에서 소개하는 시스템은 주소 동기화(URL Synchronization), 스크롤 동기화(Scroll Synchronization) 및 윈도우 크기 동기화(Window Size Synchronization) 기능을 제공하여 사용자들이 서로 다른 터미널에서 웹 브라우저를 동기적으로 이용할 수 있게 한다. 주소 동기화는 인터넷 브라우징의 이동과 방향을 동기적으로 제어해주고, 폼 동기화는 웹 페이지 입력을 실시간으로 보여준다. 스크롤 동기화는 웹 페이지의 스크롤을 동기적으로 제어하여 웹 브라우저의 출력 내용이 길어질 경우에도 문서 안의 같은 부분을 공유 할 수 있게 하며 윈도우 크기 동기화는 윈도우의 길이와 넓이를 맞춰준다.

• Journal of Power System Engineering
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• v.20 no.2
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• pp.17-25
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• 2016

In this paper, the feasibility study on a gerotor type expander as a power converting device in a small scale power generation ORC system was made by performance analysis of the gerotor expander. Design of a 1kW-class gerotor expander was carried out and its performance was numerically simulated. For a R134a Rankine system with about 20 kW solar heat source, the gerotor expander efficiency was calculated to be 35~75% for the operating conditions of $Te=80{\sim}100^{\circ}C$ and $Tc=30{\sim}60^{\circ}C$. Maximum expander efficiency was obtained at an expansion ratio somewhat higher than the design expansion ratio due to pre-expansion during suction process inside the outer and inner rotor mate. If the operating expansion ratio is not far from the design expansion ratio, the gerotor expander performance can be well compared to that of a scroll type.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.1
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• pp.64-68
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• 2015

In this paper, LED lighting system is realized by using Bluetooth wireless communications and smartphones. A bluetooth module with a lighting control function is manufactured by miniaturizing a development board of TI company and the volume of LED dimming system as a whole is reduced. And a trial product is materialized by designing a hardware composed of the manufactured bluetooth module, LED down light equipped with degree warm white and cool white, and 2-channel LED driver; and LED dimming software. The materialized trial product is controled in terms of the brightness and color temperature of LED light source using an application of a smartphone. The experiment showed that the users can easily control the intensity of illumination of LED light source by using the scroll bar of the applications of smartphones. In addition, the color temperatures of both warm white and cool white can be controlled, and when the color temperature of the trial product using the manufactured bluetooth module is compared with that of a trial product of TI company, they show the same color temperatures.

• Journal of Information Management
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• v.38 no.3
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• pp.59-80
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• 2007

In this study, we analyzed the web site navigation of law school libraries in terms of global, local, context, support navigation. The recommendations for good web site design were as follows. First, global navigation should provide the consistent navigation and be able to access to the important site and function. Second, quick links of local navigation need to provide the movement of scroll bar. The number of menu and type of link in context navigation should provide the least number. Finally, the site map and index should provide with qualified contents and minimal errors.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1058-1063
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• 2004

This paper presents a new approach regarding thermal characteristics associated with a design of the high efficiency motor. Electrical conduction materials, such as coil and aluminum embedded in the core generate high heat exerting negative influence on both lifetime and performance of machine. Thus, it is necessary to design high efficiency motor considering heat transfer in order to improve motor performance and to be protected against overheating. In this paper, firstly, numerical analysis of electromagnetic field is carried out by the nonlinear transient finite element method (FEM). Secondly, the linear static FEA of magneto-thermal field is implemented by applying source current computed by the nonlinear transient analysis. FE results are validated in terms of electromagnetics and heat transfer by experiments. And then, the pseudo-transient topology optimization using a multi-objective function is performed. The proposed method is applied to a squirrel cage single-phase induction motor of the scroll compressor.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.618-622
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• 2007

In the present study, the cooling and heating operation characteristics of a multi-heat pump have been experimentally investigated for the number of the indoor units(A, B, C) and the operating conditions. The heat pump was controlled by an inverter scroll compressor. The performance of the heat pump was measured by the multi-calorimeter of an air enthalpy method. Cooling and heating capacities and COPs were obtained at the cooling and heating temperature conditions and the setting temperatures of an indoor unit. With increasing the operation frequency of the compressor, the cooling and heating capacities of the heat pump increased linearly. The operation frequency region of the compressor was different as the combination of the indoor unit and the cooling/ heating condition.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.4
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• pp.27-35
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• 1992

By the help of computer graphics and rapid development of hardwares. GUI(Graphic User Interface) represented by WYSIWYG(What You See Is What You Get) changed user interface from liguistic model(e.g : command, etc.) to spatial model(e.g : pulldown menu, scroll bar, icon, itc.). This graphical user interface model for the ship conceptual design(MBASWIN) adopted event-driven programming technique and object-oriented concepts. Different from traditional design programs, MBASWIN is separate from the design program completely and controls all design modules. This enable a designer to accomplish a flexible designs.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.4
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• pp.336-342
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• 2012

Large-scale active solar heat systems are generally using heat exchanger between collector and storage tank loops to prevent damage by freezing. It is difficult to maintain stratification in a storage tank in the system owing to greater flow rate enhancing heat transfer. In the previous study, we introduced a spiral-jacketed storage tank and obtained good results to keep system performance of general level without better stratification. We added a scroll-shaped heat exchanger coil on the upper part in the spiral-jacketed storage tank. As a result of the experiment, it was verified that degree of stratification of the new type storage tank is higher than that of the previous one with a possibility of better collector efficiency and solar fraction.

• Journal of Families and Better Life
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• v.22 no.5
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• pp.133-147
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• 2004

Korean funeral customs are an important part of the mourning process in Korea. A survey was conducted in the southern part by the Nak-dong river, centered around the city of Busan to examine Korean funeral rites. This study was conducted with survey research. The target population included 234 teachers and experienced the death of a family member within the last three years. Results showed that they presented their condolences 5 to 6 times on average per year. Funeral rites were performed usually at a hospital funeral hall. The preference of burial to cremation was about the same. According to the survey, funeral expenses averaged 9,570,000 won and donations received for funeral expenses, 12,630,000 won. Problems the respondents expressed about the process included large funeral expenses, the decision whether to bury or cremate, and fatigue from staying up all night. When classified according to the demographic characteristics, there were significant differences in the variables. Frequency of attending funerals depended on gender, age, and health status. Condolence style depended on religion. The type of funeral (burial or cremation) depended on family income. The type of reception depended on gender. Funeral expenses depended on the age Second, in the process of preparing for a family member's death, they thought it was important to prepare a funeral ceremony portrait of the deceased and a scroll by themselves, and the preparation