• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 춘계학술대회
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• pp.808-810
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• 2011

입력영상에 대하여 전처리과정으로 배경을 분리하는 것이 영상처리 및 인식 성능에 중요한 영향을 준다. 본 논문에서는 화재검출을 위한 영상인식 전처리로 활용하는 다양한 배경추정 알고리즘에 대하여 계산량과 배경추정 성능 분석하였다. 비교하는 배경추정알고리즘은 Gaussian Running Average 추정기법, Mixture of Gaussian 모델, 그리고 KDE (kernel density estimate) 알고리즘에 대한 성능을 평가하였다. 입력영상에 대하여 배경영상차로부터 연기를 검출하는데 있어 KDE 알고리즘이 배경추정 성능은 우수한 것을 확인하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.780-783
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• 2004

Recently Intake noise has been extensively studied to reduce the engine noise. In order to diminish intake noise several resonators were added to the intake system. However this can cause a reduction of engine output power and an increase of fuel consumption. In this study, active noise control simulation of the Filtered-x LMS algorithm is applied real instrumentation intake noise data under rapid acceleration because intake noise is more excessively increased under the such a harsh condition. But the FXLMS algorithm has poor control performance when the system is disturbed. Thus modified FXLMS algorithm using L-point running average filter is developed to improve the control performance under the rapid acceleration and disturbance. The noise reduction quantity of modified Filtered-x LMS algorithm is more than original one in two cases. In the case of control for real instrumentation intake noise data, maximum residual noise of modified FXLMS algorithm is 2.5 times less than applied the FXLMS and also in the case of disturbed, the modified FXLMS algorithm shows excellent control performance but FXLMS algorithm cat not control.

• 운동영양학회지
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• 제25권1호
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• pp.1-6
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• 2021

[Purpose] We determined the effect of partial sleep deprivation (PSD) after an exercise session on exercise performance on the following morning. [Methods] Eleven male athletes performed either a normal sleep trial (CON) or a PSD trial. On the first day (day 1), all subjects performed an exercise session consisting of 90 min of running (at 75% ${\dot{V}}O_{2max}$) followed by 100 drop jumps. Maximal strength (MVC) was evaluated before and after exercise. In the CON trial, the sleep duration was 23:00-7:00, while in the PSD trial, the sleep duration was shortened to 40% of the regular sleep duration. On the following morning (day 2), MVC, the metabolic responses during 20 min of running (at 75% ${\dot{V}}O_{2max}$), and time to exhaustion (TTE) at 85% ${\dot{V}}O_{2max}$ were evaluated. [Results] On day 2, neither the MVC nor ${\dot{V}}O_2$ during 20 min of running differed significantly between the two trials. However, the respiratory exchange ratio was significantly lower in the PSD trial than in the CON trial (p = 0.01). Moreover, the TTE was significantly shorter in the PSD trial than in the CON trial (p = 0.01). [Conclusion] A single night of PSD after an exercise session significantly decreased endurance performance without significantly changing muscle strength or cardiopulmonary response.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2594-2599
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• 2011

In Korea, the HEMU-400X(High-speed Electric Multiple Unit-400km/h eXpress) has been developed since 2007 and will be operated over 400km/h in 2013. It is necessary to prepare test-bed section in Honam high-speed railroad to take the maxim running speed test for the HEMU-400X developed. In order to determine proper test-bed sections for the maximum speed of 400km/h, TPS(Train Performance Simulation) program with the data of train model, running resistance, traction power and braking capacity was used to analyze the train performances such as locations, speeds and power consumptions by times. In this study, the specifications of the HEMU-400X project and the route conditions of the Honam high-speed railroad under construction were utilized for the TPS program to determine the optimal test-bed sections for the maximum speed of 400km/h.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.192-198
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• 2004

KTX is the high speed train which is designed for 300km/h in maximum operation speed. But its long train set may cause unstable characters as swaying of the tail of a train and when the train is running on conventional line not on the high speed line, its funning safety is a point to be considered cautiously. In this study, we evaluated the running safety by the numerical analysis using VAMPIRE and compared the result with the test result of KHST, which is being in performance tests, for verifying the validity of analysis results.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.267-270
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• 2001

A lot of efforts have been made to analyze the performance of the vehicle equipped with automatic transmission through simulation. It might be necessary to understand the different types of transmissions, i.e., different power flows, for different models. If there is a module that can be applied to different types of automatic transmission, it could be helpful to transmission-related engineers. This study has started up from this idea. The common bond graph has been obtained from several types of the automatic transmission. The overall generalized equations and kinematic constraint equations have been derived using virtual power sources on common bond graph. They are used to derive state equations and constraints. These equations have been applied as an application to the vehicle equipped with two simple planetary gear set type of Ravigneaux gear type automatic transmission. The state equation, kinematic constraints, and dynamic constraints have been derived in every gear and shift operation using overall generalized equations and kinematic constraint equations. Simulations for constraint speed running, standing-start running, rolling-start running, and LA-4 mode have been conducted to analyze the performance of the vehicle powertrain using GVPS(Generalized Vehicle Powertrain Simulation) program wit pull down menus.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.863-867
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• 2003

This paper aims at the development of shoes measuring the performance of walking or running, which is equipped with electronic devices. In the in-sole of the shoes, a piezoelectric sensor is inserted for measuring the number of steps and the speed of walking. The measured signals are processed by the one-chip microprocessor and related electronic devices. Using the data, the momentum and calories of walking and running are calculated, and the results are transmitted to the displaying system composed of LCD by the RF telecommunication system.

• 한국통신학회논문지
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• 제32권1C호
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• pp.1-8
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• 2007

적응신호처리 분야에서 LMS(Least Mean Squar) 알고리즘은 수식이 간단하고, 적은 계산량으로 인해 널리 사용되고 있지만, 시간영역의 적응알고리즘은 입력신호의 고유치 분포폭이 넓게 분포할 때는 수렴속도가 느려지는 단점이 있다. 본 논문에서는 적응 신호처리의 수렴속도를 향상 시키고, 기존의 wavelet 변환을 고속으로 처리하는 고속화 알고리즘과 비교하여 적은 계산량으로 동일한 성능을 보이는 새로운 형태의 fast running FIR 필터 구조를 제안한다. 제안한 구조를 웨이블렛 기반 적응 알고리즘에 적용하였다. 실제로 합성 음성을 사용하여 컴퓨터 시뮬레이션을 통해 기존의 알고리즘과 비교 및 분석한 결과 제안한 알고리즘의 성능이 우수한 것을 알 수 있었다.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2005년도 추계학술대회 논문집
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• pp.250-255
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• 2005

본 논문에서는 적응 신호처리의 수렴속도를 향상 시키고 복잡한 계산량을 줄이는 새로운 필터 구조를 제안한다. 그리고 제안한 알고리즘을 웨이블렛 기반 적응 알고리즘에 적용한다. 실제로 합성 음성을 사용하여 적응 잡음 제거기에 적용하여 컴퓨터 시뮬레이션을 통해 제안한 알고리즘과 기존 알고리즘과의 성능을 비교한다. 그 결과 변환 영역 알고리즘은 기존의 시간영역의 알고리즘보다 수렴속도의 향상을 보였고, 웨이블렛 알고리즘, short-length fast running FIR 알고리즘, fast-short-length fast FIR 알고리즘 그리고 제안한 알고리즘에 대한 비교 연구를 수행하였다.

• Smart Structures and Systems
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• 제30권3호
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• pp.303-315
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• 2022

The degradation of wheel tread may result in serious hazards in the railway operation system. Therefore, timely wheel defect diagnosis of in-service trains to avoid tragic events is of particular importance. The focus of this study is to develop a novel wheel defect detection approach based on the relevance vector machine (RVM) which enables online detection of potentially defective wheels with trackside monitoring data acquired under different running-speed conditions. With the dynamic strain responses collected by a trackside monitoring system, the cumulative Fourier amplitudes (CFA) characterizing the effect of individual wheels are extracted to formulate multiple probabilistic regression models (MPRMs) in terms of multi-kernel RVM, which accommodate both variables of vibration frequency and running speed. Compared with the general single-kernel RVM-based model, the proposed multi-kernel MPRM approach bears better local and global representation ability and generalization performance, which are prerequisite for reliable wheel defect detection by means of data acquired under different running-speed conditions. After formulating the MPRMs, we adopt a Bayesian null hypothesis indicator for wheel defect identification and quantification, and the proposed method is demonstrated by utilizing real-world monitoring data acquired by an FBG-based trackside monitoring system deployed on a high-speed trial railway. The results testify the validity of the proposed method for wheel defect detection under different running-speed conditions.