• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.6 s.249
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• pp.531-537
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• 2006

A lever type $NO_2$ micro gas sensor was fabricated by MEMS technology. In order to heat up the gas sensing material to a target temperature, a micro heater was built on the gas sensor. The sensing material laid on the heater and electrodes and did not contact with the silicon base to minimize the heat loss to the silicon base. The electric power to heat up the gas sensor to a target temperature was measured. The temperature distribution of micro gas sensor was analyzed by a CFD program. The predicted electric power of micro heater to heat up the sensing material to the target temperature showed a good agreement with the measured data. The design of micro gas sensor could be modified to show more uniform temperature distribution and to consume less electric power by optimizing the layout of micro heater and electrodes.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.4
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• pp.69-75
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• 2017

In this study, the performances of five input split type hybrid electric vehicle sub-drivetrains were analyzed. The five sub-drivetrains consist of chain, helical gears and planetary gears. For the analyzing above five sub-drivetrains, the mathematical equations were derived. From the analysis, we found that the sub-drivetrain with chain shows slower acceleration performance and larger energy consumption on the city driving. And, the sub-drivetrain with only helical gear shows smallest energy consumption on the city driving. If the sub-drivetrain can change its gear speed, it shows fastest acceleration performance, but it has largest energy consumption on the city driving due to its additional auxiliary components.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.486-486
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• 2000

This paper is concerned with a transfer alignment method for the SDINS(StrapDown Inertial Navigation System) under ship motions. Major error sources of transfer alignment are data transfer time-delay, lever-arm velocity and ship body flexure. Specifically, to reduce alignment errors induced by measurement time-delay effects, the error compensation method through delay state augmentation is suggested. A linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonlinear measurement equation with respect to its time delay and augmenting the delay state into the conventional linear state equations. And then it is shown via observability analysis and computer simulations that the delay state can be estimated and compensated during ship motions resulting in considerably less alignment errors.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.153-156
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• 2006

The vibration isolation system is a system that attenuates the vibration transmitted from surroundings by using external energy supply like electricity and feedback and/or feedforward functions. Such a system needs stiff structure to make precise positioning without ripple within a certain bandwidth. So, a horizontal and rotary arrangement of the actuation module is suggested by using lever linkage. Modeling and kinematic formulation are completed and system identification is accomplished to tune the design variables accurately. The vibration isolation control is performed by mu-synthesis with the uncertainties in design variables. Low frequency signal enhancement circuit and saturation proof integration algorithm are devised to use seismic sensors for displacement control. This overall system shows good disturbance rejection performance.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.4 s.109
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• pp.380-386
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• 2006

ATM is a machine that receives and pays money. The gate module of ATM separates forgeries from bills and changes the transfer direction of bills. In this paper, the dynamic behavior of the gate was analyzed numerically and experimentally. The moment of inertia of the gate lever, the driving force of the solenoid and the spring force were measured, respectively. And the displacements of the plunger, the Input voltage and current were measured experimentally. The measured dynamic behaviors were simulated numerically using Maxwell program which can accommodate the electromagnetic problem of the solenoid. Through the analysis, the design factors were found to make a fast and reliable new ATM gate module.

• Proceedings of the Korean Reliability Society Conference
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• 2004.07a
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• pp.297-301
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• 2004

세탁기의 Shaft Ass'y는 모터로부터 동력을 전달 받아 세탁 및 탈수행정의 제어 기능을 수행하는 세탁기의 핵심부품으로 사용 중 브레이크 밴드소음을 유발하여 소비자의 불만족 요소로 작용하고 있다. 그러나 드럼과 브레이크 페드의 정확한 마찰소음 현상 규명이 안되어 불량 개선에 많은 어려움이 있다. 이를 해결하고자 소음, 진동, 소재 분석 및 ESPI(Electronic Speckle Pattern Interferometry) 분석을 통해 고장원인을 규명하였다. 특히 ESPI는 비접촉, Full Field 정밀 변형 가시화 장치로 Shaft Ass'y의 동작 중 공진소음 발생 부위를 변형 가시화를 통해 정확하게 찾을 수 있었다. 밴드소음 원인은 브레이크 Lever의 공진에 의해 발생하였고 브레이크 밴드 패드의 접촉면적 불균일로 인한 국부적 마찰력 증대가 소음원으로 작용하였다. 밴드소음의 정확한 고장 메커니즘 규명을 통해 개선안을 도출하여 적용하였고 밴드소음 개선효과를 얻을 수 있었다.

• Journal of the Korean Home Economics Association
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• v.33 no.2
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• pp.73-87
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• 1995

The purpose of this study was to identify the infuence of adolescent-perceived family adaptability on adolescent adjustment. The 443 subjects were selected randomly from the second grade of middle and high schools in the city of Taegu. The instruments of measurement were FACESIII, State-Trait Anxiety Inventory. Depression Scale, and Self-Esteem Scale. Factor analysis, Cronbach's α, MANOVA, and Scheff'e test were conducted for the data analysis. The major findings of this study were as follows: There differences in adolescents' adjustment by their perception of family adaptability levels. Namely, adolescents who perceived family adaptability to be low level- i.e. rigid family- felt anxiety and depression more, and adolescents who perceived family adaptability to be higher lever- i.e very flexible family-had higher self-esteem than other levels of adaptability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.7
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• pp.1437-1447
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• 1997

This paper proposes a cluster-based PCS(Personal Communication Services) network architecture to support increased signaling and control traffic. The procedures are presented to serve the mjobility management and the efficient procesing of the call-control functional using distributed servers. Especially when call-setups are made within a cluster, this distributed servers. Especially when call-setup time and the amount of control traffic of H-HLS (High level Home Location Server) in the network as L-HLS(Low lever Home Location Server) serves the call on behalf of H-HLS. Performance and reliability of the architecture have been also cairried out.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.186-188
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• 1994

Fundamental characteristics of Giant Magnetostrictive Alloy Terfenol-D$(Tb_{0.3}Dy_{0.7}Fe_{1.9\sim1.95})$ were measured by experiments. Magnetostrictions of Terfenol-D samples whose lengths are 15 and 25 mm have been measured under compressive stress from 0 to 14 MPa, when the applied magnetic field was up to 1200 Oe. The relationship between magnetostriction and field is shown graphically in the form of $H-{\lambda}$, curve. For the experiment, solenoid magnet and lever-arm-type stress equipment were designed and fabricated. The magnetostriction is measured by laser displacement measuring system and the stress applied to the sample is measured by load cell.

• Journal of Korea Water Resources Association
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• v.30 no.2
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• pp.119-129
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• 1997

A three-dimensional numerical model for the simulation of meso-scale local circulation is developed and it is applied to the land and sea breezes which take place around Ulsan. The surface temperature and moisture on the land are determined by means of the surface heat budget with a layer of vegetation considered. The vertical diffusion coefficients of momentum, heat and specific humidity at the surface layer are obtained by the lever-2 model of the turbulence closure proposed by Yamada (1982). This model proved to be effective in simulating the structure of the land and sea breezes around Ulsan.