• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.471-476
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• 2001

The characteristics of conjugated heat transfer in the inclined channel was experimentally investigated. The simulated module is attached to the bottom of the inclined channel and is heated with constant heat flux. The experimental parameters of this study are input power (Q = 3, 7W), inlet air velocity ($V_{i}=0.1{\sim}0.9m/s$) and inclined channel angle (${\varphi}=0{\sim}90^{\circ}$). The results show that input power was most effective parameter on the temperature differences between module and air. As the inclined channel angle increases, the temperatures of the module are increased. And we obtained the best condition on the conductive board when ${\varphi}=0^{\circ}$.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권5호
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• pp.185-189
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• 2005

This paper focuses on the design for Rx/Tx switch module of GSM(global standard mobile) band, characterization of a miniature, low power and dual-band implementation of the front-end switch module with low-pass filer And the effort to make agreement between the simulated design and the measured data for these solutions takes the place through accumulated design and manufacturing data library. We present the design, modeling and measurement of switch module integrating GSM Rx/Tx switching circuit and LPF(low pass filter) on a LTCC(low temperature co-fired ceramic) substrate. For GSM application, insertion and return loss of the low pass filter designed was less than 0.3 dB which was less than 12.7 dB at 900 MHz. The LTCC switch module contained 10 embedded passives and 3 surface mount components integrated on 4.6$\times$4.8$\times$1.2 mm, 6-layer multi-layer integrated circuit. The insertion loss of switch module measured at 900 MHz was 11 dB. In both of the design approach yielded excellent agreement between measured and simulated results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.433-439
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• 2001

An experimental study was carried out on the characteristics of the mixed-convection heat transfer from a protruding heat source module which had uniform heat flux and was located on a flat plate in the inclined channel. The effects of the inclined channel(${\varphi}=0{\sim}90^{\circ}$) was studied for the input power($Q=3,\;7W$) and inlet air velocities($V_{i}=0.1{\sim}0.9m/s$). Experimental results indicate that the input power was most effective parameter on the temperature differences between inlet air and module. The effects of the inclined angle was negligible when the inlet velocities were above 0.5m/s and 0.9m/s at Q = 3W, 7W respectively. As the inclined angle of the channel increases, the temperatures of the module are decreased. So we obtained the best condition on the adiabatic board at the vertical channel.

• Nuclear Engineering and Technology
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• 제49권1호
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• pp.267-276
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• 2017

In any reactor physics analysis, the instantaneous power distribution in the core can be calculated when the actual bundle-wise burnup distribution is known. Considering the fact that CANDU (Canada Deuterium Uranium) utilizes on-power refueling to compensate for the reduction of reactivity due to fuel burnup, in the CANDU fuel management analysis, snapshots of power and burnup distributions can be obtained by simulating and tracking the reactor operation over an extended period using various tools such as the $^*SIMULATE$ module of the Reactor Fueling Simulation Program (RFSP) code. However, for some studies, such as an evaluation of a conceptual design of a next-generation CANDU reactor, the preferred approach to obtain a snapshot of the power distribution in the core is based on the patterned-channel-age model implemented in the $^*INSTANTAN$ module of the RFSP code. The objective of this approach is to obtain a representative snapshot of core conditions quickly. At present, such patterns could be generated by using a program called RANDIS, which is implemented within the $^*INSTANTAN$ module. In this work, we present an alternative approach to derive the patterned-channel-age model where a simulated-annealing-based algorithm is used to find such patterns, which produce reasonable power distributions.

• 한국물환경학회지
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• 제24권4호
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• pp.488-498
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• 2008

Soil and Water Assessment Tool (SWAT) model have been widely used in simulating hydrology and water quality analysis at watershed scale. The SWAT model extracts topographic feature using the Digital Elevation Model (DEM) for hydrology and pollutant generation and transportation within watershed. Use of various DEM cell size in the SWAT leads to different results in extracting topographic feature for each subwatershed. So, it is recommended that model users use very detailed spatial resolution DEM for accurate hydrology analysis and water quality simulation. However, use of high resolution DEM is sometimes difficult to obtain and not efficient because of computer processing capacity and model execution time. Thus, the SWAT Topographic Feature Extraction Error (STOPFEE) Fix module, which can extract topographic feature of high resolution DEM from low resolution and updates SWAT topographic feature automatically, was developed and evaluated in this study. The analysis of average slope vs. DEM cell size revealed that average slope of watershed increases with decrease in DEM cell size, finer resolution of DEM. This falsification of topographic feature with low resolution DEM affects soil erosion and sediment behaviors in the watershed. The annual average sediment for Soyanggang-dam watershed with DEM cell size of 20 m was compared with DEM cell size of 100 m. There was 83.8% difference in simulated sediment without STOPFEE module and 4.4% difference with STOPFEE module applied although the same model input data were used in SWAT run. For Imha-dam watershed, there was 43.4% differences without STOPFEE module and 0.3% difference with STOPFEE module. Thus, the STOPFEE topographic database for Soyanggang-dam watershed was applied for Chungju-dam watershed because its topographic features are similar to Soyanggang-dam watershed. Without the STOPFEE module, there was 98.7% difference in simulated sediment for Chungju-dam watershed for DEM cell size of both 20 m and 100 m. However there was 20.7% difference in simulated sediment with STOPFEE topographic database for Soyanggang-dam watershed. The application results of STOPFEE for three watersheds showed that the STOPFEE module developed in this study is an effective tool to extract topographic feature of high resolution DEM from low resolution DEM. With the STOPFEE module, low-capacity computer can be also used for accurate hydrology and sediment modeling for bigger size watershed with the SWAT. It is deemed that the STOPFEE module database needs to be extended for various watersheds in Korea for wide application and accurate SWAT runs with lower resolution DEM.

• 한국자동차공학회논문집
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• 제6권2호
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• pp.118-128
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• 1998

Finite element analyses are carried out to provide results usable in the design of airbag module that consists of inflater, cushion, cover, mounting plate, etc. In the first phase, a deployment process of airbag module is analyzed to evaluate the pressure waveform of developed airbag and deployment characteristics, and is compared with the test results. Interaction between head form and inflated airbag module is investigated in the second phase. In the last stage, sled test with rigid dummy, airbag midule, driving system and car interior part are simulated to investigate the influence of airbag design factor on the behavior of dummy with seat belt. The procedures can be provided as a guideline for airbag module design and improvement of airbag module performance.

• 한국결정성장학회지
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• 제28권5호
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• pp.185-190
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• 2018

Tonpilz 트랜스듀서를 FEM 시뮬레이션인 COMSOL의 structural module을 이용하여 구현하였다. 트랜스듀서의 음압 특성과 시뮬레이션 결과를 비교하기 위하여 acoustic module을 이용하여 형성된 음압의 공간적인 분포와 실제로 트랜스듀서를 구현하여 마이크로폰으로 측정한 음압 분포를 비교하였다. 그 결과, 공진주파수와 최대 음압은 시뮬레이션의 경우는 28 kHz에서 163.5 dB로 예측되었고 실제 제작된 트랜스듀서에서는 28.84 kHz에서 137.8 dB로 측정되었다. 또한 모사된 음압 분포와 실제로 측정한 음압 분포가 유사한 패턴으로 형성되는 것을 확인하였다.

• 한국전자파학회논문지
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• 제22권6호
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• pp.577-583
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• 2011

레이더의 설계에 있어 레이더 성능 평가는 중요한 단계 중 하나이다. 그러나 조우 표적을 가지고 성능 시험을 수행하는 데는 시간 및 비용과 같은 제약점이 따르기 때문에 가상의 표적을 모의할 수 있는 장치가 개발되어 레이더 성능 평가에 사용된다. 가상의 표적 모의 장치는 광 지연 선로 및 DRFM(Digital RF Memory)을 이용하여 구현되어 왔으나, 모의 거리 및 사용 용도의 차이로 인한 시험 시나리오 구현 등에 있어 제약점을 가지고 있다. 이에 본 논문에서는 임의의 레이더 송신 신호에 대하여 정밀 거리 모의가 가능하며, 시험 시나리오 구현이 용이한 레이더 반사 신호 모의 장치 개발을 목표로 구현된 디지털 시간 지연 모듈에 대하여 기술하였다. 개발된 디지털 시간 지연 모듈은 펄스 인식 및 지연 간격 검출 방법을 적용하여 왜곡이 없는 시간 지연을 모의하다. 자체시험 결과를 통하여 성능 입증하였으며 그 결과에 대하여 기술한다.

• 대한기계학회논문집A
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• 제29권2호
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• pp.262-269
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• 2005

Optimization of a satellite structure under severe space launching environments is performed considering various design constraints. Simulate annealing, one of combinatorial optimization techniques, is used to optimize the satellite. The optimization results by the simulated annealing are compared to those by the method of modified feasible direction and genetic algorithm. Ten bar truss structure is optimized for feasibility study of the simulated annealing. Finally, the satellite structure is optimized by the simulated annealing algorithm under space environment. Weights of the satellite upper platform and propulsion module are minimized with consideration of several static and dynamic constraints. MSC/NASTRAN is used to find the static and dynamic responses. Simulated annealing has been programmed and integrated with the finite element analysis program for optimization. It is shown that the simulated annealing algorithm can be extended to the optimization of space structures.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.431-434
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• 2004

The design, simulation, modeling and measurement of a RF switch module for GSM applications were presented in this paper. switch module were simulated by ADS and constructed using a LTCC multi-layer switching circuit and integrated low pass filter, designed to operate in the GSM band. Insertion and return losses at 900 MHz of the low pass filters were designed to lower than 0.3 dB and higher than 12.7 dB respectively. The switch module constructed, contained 10 embedded passives and 3 surface mounted components integrated on $4.6{\times}4.8{\times}1.2$ m volume, 6-layer integrated circuit. The insertion loss of switch module at m MHz were around 11 dB.