• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.629-633
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• 2005

The reduction of the Vehicle interior noise has been the main interest of NVH engineers. The driver's perception on the vehicle noise is affected largely by psychoacoustic characteristic of the noise as well as the SPL. In particular, the HVAC sound among the vehicle interior noise has been reflected sensitively in the side of psychology. In previous study, we have developed to verify identification of source for the vehicle HVAC system through multiple-dimensional spectral analysis. Also we carried out objective assessments on the vehicle HVAC noises and subjective assessments have been already performed with 30 subjects. In this study, the linear regression models were obtained for the subjective evaluation and the sound quality metrics. The regression procedure also allows you to produce diagnostic statistics to evaluate the regression estimates including appropriation and accuracy. Appropriation of regression model is necessary to $R^2$ value and F-value. And testing for regression model is necessary to Independence, Homoscedesticity and Normality. Also we selected optimum layout of damping material using Taguchi method. As a result of application, sound quality is improved by more quiet, powerful, expensive, smooth.

• 대한교통학회지
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• 제24권3호
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• pp.189-195
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• 2006

지난 수십년간 자동차의 배출오염물질은 대도시 대기오염의 주요 원인이 되고 있다. 이 같은 배출가스를 줄이기 위한 정책의 일환으로 배출가스 검사제도가 실시되고 있으나, 이 검사결과에 대한 배출가스 과다차량의 요인분석에 관한 연구는 미비한 실정이다. 따라서 본 연구에서는 자동차 배출가스 규제가 엄격한 미국 캘리포니아주의 2002년 10월의 자동차 배출가스 검사결과 자료를 이용하여 자동차 배출가스 검사결과에 대한 이항로짓모형을 개발하고, 이를 통해 자동차의 과다배출가스에 영향을 미치는 주요 요인을 분석하였다. 모형추정결과, 차령. 주행거리, 엔진크기, 자동차 제조업체, 배기가스제어장치 장착여부, 검사방식 등이 배기가스 과다배출에 영향을 미치는 것으로 분석되었다.

• 대한기계학회논문집A
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• 제30권6호
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• pp.728-733
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• 2006

The reduction of the Vehicle interior noise has been the main interest of NVH engineers. The driver's perception on the vehicle noise is affected largely by psychoacoustic characteristic of the noise as well as the SPL. In particular, the HVAC sound among the vehicle interior noise has been reflected sensitively in the side of psychology. In previous study, we have developed to verify identification of source for the vehicle HVAC system through multiple-dimensional spectral analysis. Also we carried out objective assessments on the vehicle HVAC noises and subjective assessments have been already performed with 30 subjects. In this study, the linear regression models were obtained for the subjective evaluation and the sound quality metrics. The regression procedure also allows you to produce diagnostic statistics to evaluate the regression estimates including appropriation and accuracy. Appropriation of regression model is necessary to $R^2$ value and F-value. And testing for regression model is necessary to independence, homoscedesticity and normality. Also we selected optimum layout of damping material using Taguchi method. As a result of application, sound quality is improved more quietly, powerfully, even though costly, and smoothly.

• 제어로봇시스템학회논문지
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• 제22권7호
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• pp.562-569
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• 2016

This paper proposes a navigation system with a robust localization method for an underwater unmanned vehicle. For robust localization with IMU (Inertial Measurement Unit), a DVL (Doppler Velocity Log), and depth sensors, the EKF (Extended Kalman Filter) has been utilized to fuse multiple nonlinear data. Note that the GPS (Global Positioning System), which can obtain the absolute coordinates of the vehicle, cannot be used in the water. Additionally, the DVL has been used for measuring the relative velocity of the underwater vehicle. The DVL sensor measures the velocity of an object by using Doppler effects, which cause sound frequency changes from the relative velocity between a sound source and an observer. When the vehicle is moving, the motion trajectory to a target position can be recorded by the sensors attached to the vehicle. The performance of the proposed navigation system has been verified through real experiments in which an underwater unmanned vehicle reached a target position by using an IMU as a primary sensor and a DVL as the secondary sensor.

• 한국대기환경학회지
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• 제22권5호
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• pp.590-603
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• 2006

Size-and time-resolved aerosol samples were collected using an eight-stage Davis rotating unit for monitoring (DRUM) sampler from 23 March to 29 April 2001 at Gosan, Jeju Island, Korea, which is one of the super sites of Asia-Pacific Regional Aerosol Characterization Experiment(ACE-Asia). These samples were analyzed using synchrotron X-ray fluorescence for 3-hr average concentrations of 19 elements including Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, and Pb. The size-resolved data sets were then analyzed using the positive matrix factorization(PMF) technique to identify possible sources and estimate their contributions to particulate matter mass. PMF analysis uses the uncertainty of the measured data to provide an optimal weighting. Twelve sources were resolved in eight size ranges($0.09{\sim}12{\mu}m$) and included continental soil, local soil, sea salt, biomass/biofuel burning, coal combustion, oil combustion, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, and volcanic emission. The PMF result of size-resolved source contributions showed that natural sources represented by local soil, sea salt, continental soil, and volcanic emission contributed about 79% to the predicted primary particulate matter(PM) mass in the coarse size range ($1.15{\sim}12{\mu}m$) while anthropogenic sources such as coal combustion and biomass/biofuel burning contributed about 58% in the fine size range($0.56{\sim}2.5{\mu}m$). The diesel vehicle source contributed mostly in ultra-fine size range($0.09{\sim}0.56{\mu}m$) and was responsible for about 56% of the primary PM mass.

• 한국대기환경학회지
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• 제21권3호
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• pp.329-341
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• 2005

The purpose of this study is to study the $PM_{2.5}$ source characteristics affecting the Seoul area using a chemical mass balance (CMB) receptor model. This study was also to evaluate the $PM_{2.5}$ source profiles, which were directly measured and developed. Asian Dust Storm usually occurred in the spring, and very high $PM_{2.5}$ concentrations were observed in the fall among the sampling periods. So the ambient data collected in the spring and fall were evaluated. The CMB model results as well as the $PM_{2.5}$ source profiles were validated using the diagnostic categories, such as: source contribution estimate, t-statistic, R-square, Chi-square, and percent of total mass explained. In the spring months, the magnitude of $PM_{2.5}$ mass contributors was in the following order: Chinese aerosol $(31.7\%)>$ secondary aerosols ($22.3\%$: ammonium sulfate $13.4\%$ and ammonium nitrate $8.9\%)>$ vehicles ($16.1\%$: gasoline vehicle $1.4\%$ and diesel vehicles $14.7\%)>$biomass burning $(15.5\%)>$ geological material $(10.5\%)$. In the fall months, the general trend of the $PM_{2.5}$ mass contributors was the following: biomass burning $(31.1\%)>$ vehicles ($26.9\%$: gasoline vehicle $5.1\%$ and diesel vehicles $21.8\%)>$ secondary aerosols ($23.0\%$: ammonium sulfate $9.1\%$ and ammonium nitrate $13.9\%)>$ Chinese aerosol $(10.7\%)$. The results show that the $PM_{2.5}$ mass in the Seoul area was mainly affected by the Chinese area.

• 에너지공학
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• 제18권1호
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• pp.31-36
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• 2009

환경친화적인 자동차 제조 방법에는 몇 가지 방법이 있다. 하이브리드 전기자동차는 가장 현실적인 방법일 것이다. 하이브리드 전기자동차는 내연기관과 전기장치의 두 가지 동력을 사용한다. 하이브리드 전기자동차는 연료소비와 배기가스 저감을 위해서 개발되었다. 저자들은 하이브리 전기자동차의 주요 동력원으로 디젤 기관을 선택했다. 테스트는 도심버스주행모드와 고속도로주행모드가 사용되었다. 본 연구는 직렬하이브리드 전기자동차, 병렬하이브리드 전기자동차, 플러그인 직렬 전기자동차와 플러그인 병렬 전기자동차에 따른 중형디젤 하이브리드 자동차의 연료경제성과 배기가스의 시뮬레이션의 결과를 제시하고 있다.

• 한국통신학회논문지
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• 제39C권10호
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• pp.974-983
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• 2014

지능형 교통 시스템(Intelligent Transport System; ITS)의 상용화를 위한 작업이 국내외에서 활발하게 이루어지고 있는 시점인 지금 차량 간 통신 (Vehicle-to-Vehicle; V2V) 환경 해석은 관련 법규 제정에 있어서 필수적인 과정이다. 하지만 전기적으로 대형인 도로상 다수의 차량이라는 해석환경으로 인하여 계산 자원 부족으로 일반적인 수치해석 도구를 이용한 환경의 해석이 불가능한 상황에 대하여 본 논문에서는 해석 환경의 적절한 분리와 결과의 후처리로, 적은 계산 자원을 사용하여 환경 해석을 근사할 수 있는 기법을 제안하였다. 제안된 기법은 전자기원(Electromagnetic field source)과 관측 지점 주변, 그리고 그 선상의 산란체들 중 일부만을 포함하는 해석을 수행한 뒤 결과들을 중첩의 원리를 적용한 벡터합을 통하여 결과를 근사하는 방식을 사용하였다. 본 논문에서는 제안한 기법의 적용범위 및 가이드라인, 일반적인 해석 기법과의 정확도 비교를 위한 예시를 제시하였다.

• 한국항공우주학회지
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• 제45권5호
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• pp.386-392
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• 2017

본 논문에서는 700 km 고도의 태양동기궤도 진입을 목표로 하는 3단형 위성발사체에 있어서, 여러 오차 요인들로 인한 성능 오차를 보상하면서 목표 궤도에 정확히 투입시키는데 필요한 비행성능여유에 대해서 살펴보았다. 우선 궤도 투입 오차에 영향을 끼치는 다양한 오차 요인들과 각 오차 요인의 분산을 정의하였다. 이를 토대로 각 오차 요인의 영향을 독립적으로 고려할 수 있는 장점이 있는 민감도 분석을 ${\pm}3{\sigma}$ 분산 조건에 대해서 수행하였다. 여기에 여러 오차 요인에 의한 영향을 종합적으로 고려할 수 있는 Monte Carlo 분석 방법을 적용해서도 요구 추진제를 계산하였다. 결과적으로 두 방법을 통해 얻어진 비행성능여유를 비교했으며, 유사한 수치가 도출됨을 확인하였다.

• 한국소음진동공학회논문집
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• 제15권8호
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• pp.945-953
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• 2005

The purpose of this paper is to develop a linear regression model for the sound quality index of vehicle Interior noise. For this, objective measurement data of the vehicles driving in acceleration was measured. On the basis of analysis, psychoacoustic parameters were extracted and subjective evaluation was performed by noise and vibration expert evaluators. For the subjective evaluation, the paired comparisons and the semantic differential methods were used to evaluate sound quality of vehicle interior noise. By the paired comparison which evaluate two pairs of vehicle interior noise, the preference was estimated. With the semantic differential and the factor analysis, it was evaluated words of two pairs which expressed appropriately the sense of evaluator about noise source. Therefore the characteristics of the sound qualify for the vehicle were differentiated. From the results of both the correlation analysis and the multiple factor regression analysis, the sound quality evaluation model for the sense of human hearing was derived and indexed.