• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.12-22
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• 2007

This paper presents to predict the powertrain structure-borne noise which is primary resource of interior noise. As the first step, it is built up a hybrid powertrain model which is based on the real powertrain which is verified with static and dynamic properties. The methods for verifying are modal analysis and running vibration testing which are experimentally implemented. Based on the Hybrid powertrain component model, an initial predictive assembly model is simulated. As the second step, the characteristic transfer functions are measured that are dynamic stiffness of rubber mounts and vibro-acoustic transfer function based on the acoustic reciprocity. Several techniques utilizing special experimental devices have been proposed for this research. Finally, the structure-borne noise by powertrain will be predict and verify with dynamic simulation and experiment.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.100-103
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• 2011

In the present work, a numerical study of fluid flow and heat transfer on the concave surface with impinging jet has been performed by solving three-dimensional Reynods-averaged Naver-Stokes(RANS) equations. The constant temperature condition was applied to the concave impingement surface. The inclination angle of jet nozzle and the distance between jet nozzles are chosen as design variables under equivalent mass flow rate of working fluid into cooling channel, and area averaged Nusselt number on concave impingement surface is set as the objective function. Thirteen training points are obtained by Latin Hypercube sampling method, and the PEA model is constructed by using the objective function values at the trainging points. And, the sequential quadratic programming is used to search for the optimal paint from the PBA model. Through the optimization, the optimal shape shows improved heat transfer rate as compared to the reference geometry.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.35-42
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• 2009

One of the problems we face up at the time of planning or improving a transportation transfer facility is which modes and how close we have to put together. The goal here is to keep the connecting transportation mode as close as possible to the prime transit mode, so people travel a minimum transfer path, a distance from one mode to another. Too much a physical separation between modes will limit, even with an intensive improvement of the component links, the level of service of a transfer path as a whole. This study defined a transfer path as the whole stretch of the distance from an arrival point of one mode to the departure point of the connecting mode. The transfer path was divided into three typical segments as side walk, stairways, and indoor corridors. Preference surveys were made for each of these segments, resulting in relative resistance. The sum of individual segments weighted with the relative resistance will make a transfer resistance of the path, which in turn constitutes a transfer utility function together with the overall satisfaction score obtained by the interview survey. The transfer utility function has been utilized to evaluate the transfer distance between modes.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.6
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• pp.440-444
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• 2016

In this paper, an equivalent circuit model for near-field noise emission is proposed to implement a multimedia operation-monitoring system for mobile devices. The proposed model includes a magnetic field probe that captures noise emissions from multimedia components, and a transfer function for near-field noise coupling from a transmission line source to a magnetic field probe. The proposed model was empirically verified with transfer function measurements of near-field noise emissions from 10 kHz to 500 MHz. With the proposed model, a magnetic field probe was optimally designed for noise measurement on a camera module and an audio codec in a mobile device. It was demonstrated that the probe successfully captured the near-field noise emissions, depending on the operating conditions of the multimedia components, with enhanced sensitivity from a conventional reference probe.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1512-1516
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• 2007

자신의 현재와 과거의 시계열데이터만을 가지고 시계열 모형을 구축하는 단변량 ARIMA모형 분석법과는 달리, 관심의 대상이 되는 출력시계열과 이와 관련있는 입력시계열의 동태적 특성을 나타내는 전이함수모형(Transfer function model)을 사용하여 소양강댐, 충주댐, 화천댐에 대한 월별 수문자료를 이용하여 유입량을 예측해 보고자 한다. 본 연구의 주요 목적은 다변량 추계학적 시스템의 해석을 위한 모형의 추정과 등정을 위한 과정을 개발하는데 있다. 일반적 추계학적 시스템 모형이 표현되며 그것으로부터 수문학적 시스템의 모형을 매우 적절하게 유도하기 위한 다중 입력-단일 출력 TF, TFN모형을 유도하는데 있다. 이 모형은 수문학적 시스템을 위한 경우에 있어 상관된 입력을 설명할 수 있도록 개발된다. 일반적으로 모형을 만드는 전략이 유도되며 실제유역시스템에 적용하여 검토된다. 한강수계 주요 다목적댐인 소양강댐, 충주댐, 화천댐의 수문자료를 가지고 추계학적 모형(TF, TFN)에 의한 결과와 실제유입량을 비교하여 검토하고자 한다.

• Journal of Environmental Science International
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• v.22 no.4
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• pp.415-424
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• 2013

In this paper, time series of soil moisture were measured for a steep forest hillslope to model and understand distinct hydrological behaviours along two different transects. The transfer function analysis was presented to characterize temporal response patterns of soil moisture for rainfall events. The rainfall is a main driver of soil moisture variation, and its stochastic characteristic was properly treated prior to the transfer function delineation between rainfall and soil moisture measurements. Using field measurements for two transects during the rainy season in 2007 obtained from the Bumrunsa hillslope located in the Sulmachun watershed, a systematic transfer functional modeling was performed to configure the relationships between rainfall and soil moisture responses. The analysis indicated the spatial variation pattern of hillslope hydrological processes, which can be explained by the relative contribution of vertical, lateral and return flows and the impact of transect topography.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.735-740
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• 2003

In this study, a numerical optimization to find the optimal shape of streamwise periodic ribs mounted on both of the principal walls is performed to enhance turbulent heat transfer in a rectangular channel. The optimization is based on Navier-Stokes analysis of flow and heat transfer with $k-{\varepsilon}$ turbulence model and is implemented using response surface method. The width-to-height ratio of a rib, rib height-to-channel height ratio, rib pitch to rib height ratio and distance between opposite ribs to rib height ratio are chosen as design variables. The object function is defined as a function of heat transfer coefficient and friction drag coefficient with weighting factor. Optimum shapes of the rib have been investigated for the range of 0.0 to 0.1 of weighting factor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.934-938
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• 2008

To customize individual characteristics of HRTF, a spherical model has been used for structural modeling technique. A pseudo-code of prolate spheroidal HRTF caused by incident acoustic point source is already developed, and it can be used a head shadow filter for structural modeling of HRTF. In this research, to see the necessity and efficiency of spheroidal head modeling, ITD optimization is performed on CIPIC HRTF database. From given cost function, ITD-optimized spheroidal head model, whose ITD information is the most matched version of measured ITD information, is found by varying head parameters subject by subject. By comparing results of ITD-optimized spheroids and ITD-optimized spheres, we concluded that a spherical head model is more efficient way of generating head shadow effect than a spheroidal head model does.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.51-56
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• 1998

In this paper, we analyze the effects of scaling factors on the performance of a fuzzy logic controller(FLC). The quantitative relation between input and output variables of FLC is obtained by using a qualsi-linear fuzzy model, and an approximate transfer function of FLC is dervied from the comparison of it with the conventional PID controller. Then we analyze in detail the effects of scaling factor using this approximate transfer function and root locus method. Also we suggest an on-line tuning method for scaling factors which employs an sample performance function and a variable reference for tuning index.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.2
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• pp.147-154
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• 2012

In this paper, we revise the JDL data fusion model to have an ability of distributed data fusion(DDF). Data fusion is a function that produces valuable information using data from multiple sources. After the network centric warfare concept was introduced, the data fusion was required to be expanded to DDF. We identify the data transfer and control between nodes is the core function of DDF. The previous data fusion models can not be used for DDF because they don't include that function. Therefore, we revise the previous JDL data fusion model by adding the core function of DDF and propose this new model as a model for DDF. We show that our model is adequate and useful for DDF by using several examples.