• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.259-260
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• 2020

기존의 전동휠체어를 사용하는 약자 또는 중증 장애인 등 지체(肢體)가 불편한 사람들이 휠체어 사용 시 생기는 문제점을 해소할 목적으로 시작되었다. 이는 전동휠체어가 보행 기구임에도 자동차에 준하는 교통사고에 대해 무방비하게 노출되고, 중증 장애인에 대한 이동권 보장이 아직 미흡하여 생기는 문제이다. 따라서 본 연구에서는 이러한 문제로 인한 불편함을 해소하고자 아이트래킹을 이용한 스마트 전동휠체어 기술을 적용하고자 한다. 루게릭병 등으로 인해 지체(肢體)의 움직임에 제한이 있는 사람들에게 보호자가 밀어주는 휠체어에 의존하는 것이 아닌 Eye-Tracker를 이용한 시선 추적(Eye-Tracking) 기술로 휠체어 동작이 가능하다. Web-Cam과 라즈베리 파이를 통해 얻은 전·후·좌·우의 영상정보를 디스플레이 화면에 송출한다. 그 후 Eye-Tracking 기술을 이용해 디스플레이 화면에 표시된 전·후·좌·우 이동에 관한 UI(User Interface)룰 사용자가 송출된 영상을 보면서 눈의 움직임만으로 선택해 휠체어의 방향을 제어한다. 또한 전동휠체어의 조작 실수로 다른 행인 또는 장애물과 충돌하는 문제점을 초음파 센서를 이용하여 일정 거리 내에 사물이나 사람이 있을 경우 디스플레이 화면에 경고표시 및 경고음, 각 초음파 센서 위치에 맞는 LED작동으로 사용자들에게 추돌 위험경고와 함께 장애물의 위치파악이 가능하도록 한다. 따라서 스마트 전동휠체어를 통하여 수동적인 움직임이 아닌 능동적이고, 초음파 센서로 인해 안전한 이동이 가능하게 한다.

• Journal of IKEEE
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• v.23 no.1
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• pp.224-229
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• 2019

Seat of automobile is required to support the comfort to driver and passenger during the driving. The control method of the seat position is changed from manual type to power type, which means using the motor to increase the comfort of the driver. By using the motor, several problems, such as vibration, noise, and over-current, appeared. These problems can be reduced through the control of seat motor. In this study, a control technology of four control variables, which determine profile of the input voltage applying to the seat motor, is proposed to generate the current profile having soft-start and soft-stop. The current flowing through the coil by input voltage is described by mathematical modeling of power seat. It is confirmed that optimized current profile having soft-start and soft-stop can be generated from simulation using the mathematical model.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.1
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• pp.22-39
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• 2021

This study estimated mode choice models for access travel and neighborhood travel from an SP survey in metropolitan areas where shared e-scooter services are offered. Model results show that travel time and travel cost have negative effects on mode utility. It is also revealed that people are more sensitive to travel time in access travel, whereas they are more influenced by travel cost in neighborhood travel. Looking at individual and household attributes, it has a positive effect when under 40 yerars of age, owning bikes, being a public transportation user, while it has been shown a negative effect in less than 3 million won in monthly household income and owning individual cars.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.2
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• pp.200-207
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• 2000

Recently, it is increased to apply the inverter system to household electrical appliances, especially in the air c conditioners, refrigerators and washing machines, to reduce the power consumption and the acoustic noise by t the low speed operation, and to make their functions more comfortable for human beings. For the inverter s systems, however, it is highly required to reduce the undesirable electromagnetic noise and psychoacoustic n noise generated by PWM for variable speed operation. In this paper, the electromagnetic noise for the d detenninistic PWM and random PWM for the reciprocating compressors driven by the brusWess dc motor was a analyzed. It was also verified through the experiment that the elt'Ct$\tau$omagnetic noise was reduced and the s sound quality was improved by applying the random PWM.

• Journal of KSNVE
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• v.8 no.2
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• pp.289-296
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• 1998

To predict the noise propagation from an elevated railway, sound radiation characteristics of elevated structure are measured by using the sound intensity method. In the base of the results, we propose the source model of elevated structure noise and the calculation model for elevated railway noise. Acoustic model of the former is modeled a row of single sources with directivity cos .theta. positioned in the center of a bogie and arranged in the lower side of slabs. Also prediction model is presented with rolling noise and elevated structure noise calculated by considering the power level of a source for one-third octave band, ground absorption and barrier deflection. Noise level unit patterns of a passing train is calculated based on this model and the results are compared with available field data.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.3
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• pp.224-229
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• 2004

In order to control the railway noise, the radiation characteristic of the noise when the train passes by should be analyzed. Generally, the major noise sources of the Korea Train Express are the rolling noise and power unit noise up to 300km/h. In this paper, a train model that is considered to be a row of point sourcesis introduced to analyze the radiation characteristic. The analysis results are compared with the measurement ones. It is shown that the propagation characteristic of the rolling noise is a dipole type and the noise generated by the power unit is radiated as a cosine type. With increasing of the train speed, the noise level at a receiving point is increased in the direction of motion and reduced in the direction opposite to the motion. The analysis results including the moving effect of the noise source at 300km/h show good agreement with the measurement results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.25-28
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• 2005

The interior noise of KTX in tunnel is becoming the problem since the commercial operating in April 2004. The major sources of interior noise for High speed train ate known as the aerodynamic noise and rolling noise generally. We measure the noise and vibration inside KTX in tunnel in order to find the cause of the interior noise of KTX. The analysis results show that the interior noise of KTX in tunnel with concrete track is increased sharply by a low frequency below 80Hz that is the natural frequency of the KTX carbody. We know that the booming noise inside KTX in tunnel with concrete track is generated by aerodynamic noise outside ganqway and rolling noise at the carbody natural frequency.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.337.1-337
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• 2002

In order to control the railway noise, the radiation characteristic of the noise during the train passage should be analyzed. Generally, the major noise sources for Korean Train Express are the rolling noise and power unit noise up to 300km/h. In this paper, we describe on a train model that is considered to be a row of point sources to calculate the radiation characteristic. The calculation results are compared with short distance measurement. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.829-835
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• 2001

The sources of wayside noise for the high speed train are the aerodynamic noise, rolling noise and power unit noise. One of the best ways to control the wayside noise is to analysis the noise level. In this paper, we measure the wayside noise and the vibration of the rail/sleeper for Korean Train Express (KTX) and compare with the results for the conventional train. The measurement results for KTX show that the characteristics of the noise and vibration are different from the conventional train and the rolling noise and power unit noise are the major sources.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.9
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• pp.668-673
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• 2002

The sources of wayside noise for the high -speed train are the aerodynamic noise, rolling noise and power unit noise. We should know the major source to control noise radiated from train. In this paper, we present the test results on the wayside noise and the vibration of the rail/sleeper during the passing of Korean Train Express (KTX). It turns out that the major noise sources for KTX are the rolling noise and power unit noise at 300 km/h. Generally, the noise attenuation with distance is independent of train speed. However, the test results show that in the near field the noise levels decrease by about 5~6 ㏈(A) per doubling of distance at speed in the range of 50~120 km/h and about 3~4 ㏈(A)/d.d at 300 km/h.