• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1995.06b
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• pp.21-27
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• 1995

소결마찰재의 기공은 소결체의 기본 특성으로 제조공정에 따라 다양하게 형성되며, 기공량이 증가할수록 소결체의 강도나 경도를 낮추는 결과를 초래하지만, 수지령 마찰재료의 경우 일정량의 기공이 오히려 마찰특성에는 양호한 결과를 나타냈다. 소결 마찰재의 경우, 기공향은 제작공정상 성형압과 소결 가압력을 선정하는 기준이 되는 것이지만 아직까지 정량화된 결과가 알려져 있지 않다. 따라서 본 연구는 동계소결 마찰재의 제조공정에서 기본적으로 내재되는 기공이 마찰특성에 어떠한 영향을 주며 또한 이러한 영향에 따라 최적 마찰특성을 나타내는 기공량을 제시하고자 하였다. 소결마찰재의 기공율은 성형체 밀도와 소결 가압력을 임의로 변화시켜 기공향을 조절하였고, 이렇게 만들어진 시편들은 정속식 마찰시험기를 이용하여 마찰특성을 평가하였다. 결과의 분석은 반복이 있는 이원배치법을 이용한 통계 수단을 사용하여 분산분석을 실시하고, 최적의 마찰특성을 나타내는 성형체 밀도와 소결 가압력을 제시하고자 하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1996.04a
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• pp.99-107
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• 1996

Examined in this paper is the effect of B$_{4}$C addition on the frictional characteristics of Cu-Sn based sintered friction material. For the specimens 1%, 2% and 4% of B$_{4}$C were added into the reference material. A pin-on-disk type friction tester was used to measure the friction and wear with respect to the surface temperature and sliding distance. Wear mechanism of each specimen is analyzed in the view point of the oxide film formation. The specimen containing 4% of B$_{4}$C showed stable friction and low wear since the oxide film was sustained up to higher surface temperature ranges.

• The Journal of Korean Medicine
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• v.23 no.3
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• pp.33-42
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• 2002

Objective : This study was performed to investigate the activity of Whagan-Jeon (huaganjian) in protection against acetaminophen (AAP)-induced hepatotoxicity and the possible mechanisms in vivo. Methods : The following were performed : Serum ALT, depletion of hepatic glutathione (GSH) levels, the microsomal p. nitrophenol hydroxylation activity, microsomal aniline hydroxylation activity, genomic DNA fragmentation and its reversal, hepatic glutathione-S-transferase (GST) activity, and hepatic NAD(P)H:quinone oxidoreductase (QR) activity Results : Whagan-Jeon (huaganjian) protected against AAP-inducedhepatotoxicity by the increase of GSH levels, inhibition of P450 2E1-specific metabolic activities, attenuation of hepatic DNA damage, and induction of GST and QR activities in vivo. Conclusions : In conclusion, Whagan-Jeon (huaganjian) was effective in protection against AAP-induced hepatoxicity.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2010.09a
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• pp.384-386
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• 2010

본 연구의 목적은 도시고온화와 도시열섬 현황을 파악하는데 있어 중요한 역할을 하는 도시 지역의 알베도와 지표면의 토지이용 자료를 이용하여 한반도 행정구역의 알베도 분포를 비교 평가하고자 하는 것이다. 도시 지역의 알베도와 토지이용을 현장조사 할 경우 많은 시간과 비용이 소요되기 때문에, 시간적 경제적인 비용절감효과를 위해 전 지구적으로 변화를 감지할 수 있도록 NASA에서 제공하는 MODIS 위성영상 자료를 사용하여 분석하였으며, 그 결과 서울, 부산, 대구 등 주요 도시를 중심으로 대체적인 알에도 값이 낮게 나타났다. 이는 도시 지역의 인공 환경의 영향으로 인하여 주요 도시 지역이 주변 지역보다 알베도 수치가 낮게 나타났음을 알 수 있고 이러한 알베도 수치는 도시 열환경에 직접적인 영향을 주고 있으며 따라서 도시고온화와 도시열섬 현상을 감소시키기 위하여 도시 내 빌딩 및 도로의 재질개선, 지붕 및 도로 포장, 건물의 외벽을 밝은 색으로 교체 등의 방법으로 지표면 알베도를 높이기 위한 방안 마련이 시급 할 것이다.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2875-2878
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• 2003

In this paper, we propose an EEG-based mental state prediction method during a mental tasks. In the experimental task, a subject goes through the process of responding to visual stimulus, understanding the given problem, controlling hand motions, and hitting a key. Considering the subject's varying brain activities, we model subjects' mental states with defining selection time. EEG signals from four subjects were recorded while they performed three mental tasks. Feature vectors defined by these representations were classified with a standard, feed-forward neural network trained via the error back-propagation algorithm. We expect that the proposed detection method can be a basic technology for brain-computer interface by combining with left/right hand movement or cognitive decision discrimination methods.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.12
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• pp.19-29
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• 1997

This paper presents stable kinematic modeling and path planning and path tracking algorithms for the poisition control of 4-wheeled 2-d.o.f(degree of freedom) mobile robot. We drived the actuated inverse and sensed forward solution for the calculation of actuator velocity and robot velocities. the deal-reckoning algorithm is introduced to calculate the position of WMR in real time. The gaussian functions are applied to control and to design the smooth orientation angle of WMR and the path planning algorithm for obstacle avoidance is prosed. We composed feedback control system to compensate for error because of uncertainty kinematic modeling and measurement noise. The simulation resutls show that the proposed kinematkc modeling and path planning and feedback control algorithms are useful.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.354-358
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• 2007

This article presents several methods of mobile communication network to access technologies utilizing unlicensed spectrum interworking. Generic Access Network (GAN) technology was already specified in GERAN (GSM EDGE Radio Access Network) and Interworking WLAN (I-WLAN) was standardized for WCDMA system for WLAN user to access WCDMA packet based services through WLAN access point. Voice Call Continuity is not access network dependent technology but is a kind of domain change scheme for voice call from Circuit Switching (CS) network to IP Multimedia Subsystem (IMS) and vice versa.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.531-532
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• 2011

본 연구는 아동 51명을 대상으로 키보드의 특정버튼(Enter, 숫자키, 방향키), 마우스 포인터, 마우스 오른쪽버튼과 왼쪽 버튼의 조작 시간을 체크하여 각 인터페이스별 조작능력을 살펴보았다. 연구결과, 키보드와 마우스 조작시간에는 월령과 성별에 따른 차이보다는 개인에 따른 편차가 큰 것으로 나타났다. 문항별 반응시간을 비교하였을 때, 키보드버튼조작 평균 반응시간2.97초(5.62), 마우스포인터조작 반응 평균 반응시간 58초(.43), 마우스버튼조작 반응 평균 반응시간 3.02초(1.49)로 나타났다. 각 하위영역별로 조작시간 편차가 큼을 고려할 때, 기본인터페이스 조작능력은 개인에 따라 차이가 나타남을 알 수 있다.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.315-321
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• 2004

Dawin Friction Corp. has been advanced sintered brake pad for Korean concept high speed train (so called G7 train) with KRRI, You Jin and Rotem without the assistance of foreign company. In the course of development, the evaluation of our and foreign disk pads was performed by lab scale dynamometer and full scale dynamometer. As the result of dynamo test, it is shown that our developed brake disk is equal or superior to those of foreign companies in many respects, for example, wear resistance, noise, etc. The new brake pad which is developed through 'post G7-project' is equipped with G7 train and is under many tests without any problems at the present moment.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.271-276
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• 1998

To apply the wear resistant steel plate for heavy duty vehicle, the wear characterisms of various kinds of commercial steel plates were invesigated by dry sand/rubber wheel tester which was tested under scratch abrasion mode. The wear tested pnaterials were boron steels which were manufactured by thereto machanical control process (TMCP) in order to achieve higher hardness. As the result of the test, wear resistance of steel plate increases with the hardness and carbon content. The wear loss of wear resistance steel plate (Hv440) is a half times than tinat of SWS490A (Hv160) steel plate in dry sand-rubber wheel test and the result in field test is similar to this dry sand/rubber wheel test result. Therefore, dry sand/rubber wheel tester can be used to predict the scratch abrasion life of the parts for heavy duty vehicle.