• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.168-175
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• 2006

An experimental study was conducted to investigate the effect of the morphology of CNT on the thermal conductivity of suspensions. The effective thermal conductivities of the samples were measured using asteady-state cut bar apparatus method. Enhancements based on the thermal conductivity of the base fluid are presented as functions of both the volume fraction and the temperature, Although functionalized SWNT produiced a more stable and homogeneous suspension, the addition of small amounts of surfactant to suspensions of 'as produced' SWNT demonstrated a greater increase in effective thermal conductivity than functionalized SWNT alone. The effective thermal conductivity enhancement corresponding to 1.0 percent by volume approached 10%, which was observed to be lower than expected, but more than twice the values, 3.5%, obtained for similar tests conducted using aluminum oxide suspensions. However, for suspensions of MWNT, the degree of enhancement was measured to be approximately 37%. It was postulated that the effect of clustering, resulting from the multiple heat-flow passages constituted by interconnecting neighboring CNT clusters, played an important role in significant enhancement of effective thermal conductivity.

• 로봇학회논문지
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• 제4권2호
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• pp.112-120
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• 2009

In this paper, a localization error recoverymethod based on bias estimation is provided for outdoor localization of mobile robot using different-type sensors. In the previous data integration method with DGPS, it is difficult to localize mobile robot due to multi-path phenomena of DGPS. In this paper, fault data due to multi-path phenomena can be recovered by bias estimation. The proposed data integration method uses a Kalman filter based estimator taking into account a bias estimator and a free-bias estimator. A performance evaluation is shown through an outdoor experiment using mobile robot.

• 로봇학회논문지
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• 제4권2호
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• pp.130-138
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• 2009

Recently, people tracking technology is being required to various area including security application. This paper suggests a method to track people with multiple laser scanners to detect the waist part of human. Multi-target model and Kalman filter based estimation are employed to track the human movement. The proposed method is applied to a novel system to monitor the entrance area and to filter out the trespasser to pass through the door without identification. Experiments for various cases are performed to verify the usefulness of the developed system.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.414-417
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• 2007

A methodology for XML documentation of the structural calculation document is presented to support manipulation of the design information on the internet. The text file format is chosen as a neutral format because it can be easily translated from office documents generated from engineering practice. The first word of each line is compared with the reserved numbering groups, and relative levels among the lines are defined to generate the hierarchically structured XML document of the text file. The demonstration subjected to sample general documents and structural calculation documents shows that the prototype application module based on the developed methodology can be adopted to build the database of design information which supports the safety management of infrastructures.

• 한국광학회:학술대회논문집
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• 한국광학회 2002년도 하계학술발표회
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• pp.100-101
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• 2002

He-Ne 레이저를 머리카락에 조사시키면 스크린에 단일 슬릿에 의한 회절무늬와 같은 형태의 무늬가 나타난다. 그래서 일반적으로 머리카락 슬릿에 의한 회절무늬를 단일 슬릿에 의한 회절무늬로 기술하는 경향이 있다. 그러나 단일 슬릿에 의한 회절무늬와 머리카락 슬릿에 의한 회절무늬를 비교해 보면 아래 사진에 나타난 것 같이 단일 슬릿에서는 중앙의 제 1 극대점이 밝은 선으로 되어 있지만 머리카락 슬릿에서는 중앙에 밝은 spot이 나타나는 것을 관찰할 수 있다. 따라서 본 연구에서는 이 중앙의 spot무늬가 왜 발생하는지 그 원리를 이론적으로 규명하고 실험하는데 목적이 있다. (중략)

• 한국정밀공학회지
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• 제18권6호
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• pp.74-79
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• 2001

In this study, a failure mode analysis of CNC machining center is described. First, the system is classified through subsystems into components using part lists and drawings. The component failure rate and failure mode analysis are performed to identify the weak components of a machining center with reliability database. The failure probabilistic function of mechanical part is analyzed by Weibull distribution. The Kolmogorov-Smirnov test is also used to verify the goodness of fit.

• 전자통신동향분석
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• 제19권6호통권90호
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• pp.34-42
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• 2004

우리나라는 전국적인 초고속 정보통신망을 구축하고, 전체 가구의 70%(약 1천만 세대)가 초고속 인터넷에 가입하는 등 세계 최고의 정보 인프라를 보유한 IT 강국임은 주지의 사실이다. 그러나 최근 정보통신환경은 인터넷 서비스의 복합, 다양화, 고품질, 고속화 추세로 인해 xDSL 등 기존 기술의 한계를 해결할수 있는 새로운 차세대 가입자망(FTTH) 기술이 요구되고 있는 실정이다. 본 고에서는 국내외 FTTH 기술및 시장 현황을 살펴보고 향후 FTTH 장비 시장 규모를 예측함으로써 우리나라의 FTTH 추진 현주소를파악하고 향후 추진방향을 모색하고자 한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.199-200
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• 2006

Transparent conductive alum mum-doped ZnO (AZO) films have been prepared on polycarbonate (PC), Coring 7059 and Quartz substrates by DC sputtering method at room temperature. Films deposited was evaluated about spectra of X-ray diffraction and transmittance and characteristics of films deposited as kind of substrate was compared. Films deposited showed (002) orientation and all AZO films are transparent over 80% within the visible wavelength region.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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• pp.269-271
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• 2006

In power system, the reactive power is closely associated with voltage. In addition Reactive power has localized characteristic. Recently wide area blackout caused by reactive power imbalance. Therefore it is important to control reactive power considering its characteristic. Until now maintenance of system voltage has been controlled by shunt compensation rather than generators. However because of a large time-constant, shunt compensators are difficult to manage disturbances immediately. In addition shunt compensation has discrete characteristic, which make disturbances in system. In this paper we studied the voltage maintenance method of local buses by controlling the reactive power output of a generator which is closely related a load bus in addition the proposed method was verified by test system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.1010-1013
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• 2000

In this study, a failure mode analysis of CNC machining center is described. At first, the system is classified through subsystems into components using part lists and drawings. The components failure rate and failure mode analysis are performed to identify the weak components of a machining center with reliability database. The failure probabilistic function of mechanical part is analyzed by Weibull distribution. The Kolmogorov-Smirnov test is also used to verify the goodness of fit.