• The Journal of the Acoustical Society of Korea
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• v.35 no.4
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• pp.288-294
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• 2016

The space between tire and wheel guard acts as a path for tire pattern noise transmission. In this study, acoustic phenomenon occurring in the tire-wheel guard space is investigated using acoustic mode analysis and visualization of the sound pressure distribution over the wheel guard surface. We introduced a cavity over the wheel guard surface to reduce the tire pattern noise, where the cavity acts as an acoustic damper. The interior noise was reduced by 2 dB(A), and the noise control measures treated in this study may provide an efficient method to improve interior sound quality without increasing cost and weight at the final stage of the vehicle development.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.830-835
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• 2004

In railway systems, the performance of turnout is one of the most important factors to improve the train's speed. Standard turnout, in which one track is split in main track side and turnout side. Because the main track side remains linear, speed restriction can be alleviated while train pass the main track side. The factors of speed restriction in main track side are strength of crossing and tongue rail, wheel back side pressure of guard rail and wing rail. In this study, we measured wheel back side pressure of guard rail to compare improved turnout with present turnout. In result, the wheel back side pressure of improved turnout was lower than present turnout, so its performance was proved.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.12-18
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• 2014

This paper describes about the development of new concept's rear wheel guards for the reduction of Road Noise in the passenger vehicle using test. The new wheel guards are proposed by various frequency chamber concept and different textile layers concept. Two wheel guards were verified by small cabin resonance test and vehicle test. Through new developing process without vehicle test, Result of road noise will be expected when new concepts and materials of wheel guard is applied into automotive vehicle. As a result of the application of Aimed Helmholtz and Multi-layers concept, this paper classifies the road noise, cost and weight are reduced by new concepts and the solutions are adopted into the 2 cars.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.6
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• pp.545-551
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• 2009

A small guard robot working indoors or outdoors can be used to report various information on its environment to an operator. The guard robot should be small-sized and lightweight to increase its portability. In addition, it should be able to overcome a relatively high obstacle to cope with various situations. To satisfy these requirements, this paper presents a small robot equipped with a novel hybrid wheel and track mechanism that can select wheels or tracks depending on the situation. The robot folds the tracks into the body in the wheel mode and only wheels are active with the tracks immobilized, which results in the fast moving speed. In the track mode, the tracks are extended to keep in contact with the ground. Furthermore, this research proposes the belt length maintenance mechanism by which the belt length is kept constant in either the wheel or track mode. Various experiments demonstrate that the proposed robot can move fast by using wheels on the smooth terrain and overcome obstacles by using tracks on the rough terrain.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.11
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• pp.1108-1114
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• 2009

Mobility is one of the most important features for a guard robot since it should be operated in rough places. A wheel-based mobile robot capable of jumping is an appropriate structure for a guard robot because it can easily satisfy the requirements for small guard robots. The jumping robot can reach a higher place more rapidly than other locomotion methods. This research proposes a small robot equipped with the jumping mechanism based on the conical spring with the variable length endtip. The variable length endtip enables the independent control of the jump force and jump angle which are related to the jump height and jump distance, respectively. Various experiments demonstrated that the proposed jumping mechanism can provide the independent control of jump force and jump angle, and improve the mobility of a small robot to overcome an obstacle. Furthermore, a combination of the jumping mechanism and the PSD sensor to measure the distance to the step enable the jumping robot to autonomously climb stairs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.1115-1118
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• 2015

Two wheel type electric vehicles driving with the electric motors for guard are used increasingly at the airport and harbor place to move between narrow indoors. This type two wheel electric vehicles are powerd by batteries and using the steering control apparatus including multi sensors and handle operating device for forward and backward, rotating moving. At this research, we design sensor interfacing electronic control system use only the center of foot balance without the handle type steering apparatus. This design is for safety of drivers at one's cornering.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.723-730
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• 2013

The speed-limit regulation on a turnout is the main factor inhibiting the speed-up of conventional lines. The specified speed for a train moving through a turnout system is lower than that for a train traveling over the general track. This is done to ensure the running safety of a railway vehicle moving through a turnout. In this study, the shape change example of the guard rail component of a turnout in the Daegu Metropolitan Transit Corporation (DTRO) system was studied. A theoretical examination of the geometrical interaction formula according to wheel/rail shape at the turnout was conducted. Running safety analysis by changing the length of the guard rail on the F10/F12 turnout using the developed analysis techniques (by VI-Rail) was achieved, and the effect on railway safety was examined accordingly.

• Journal of the Korean Society of Safety
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• v.38 no.1
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• pp.42-54
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• 2023

Mobile scaffold is used as a work platform in construction sites. According to industrial accident data, 10 fatalities occur annually on average due to falling from mobile scaffold in construction sites. To prevent such fatal accidents, safety standards must be improved by analyzing the causes of fatal accidents related to mobile scaffold. Accordingly, we analyzed domestic and international safety standards for mobile scaffold and analyzed the fatalities (117 persons) caused by mobile scaffold accidents in domestic construction sites during 2011-2020 and found that fall, overturn, and collapse accounted for 88% (103 persons), 10.3% (12 persons), and 1.7% (2 persons) of fatalities, respectively. The main causes of fatal accidents were found to be non-installation or insufficient installation of safety rails and outriggers and incorrect sequence of work. Based on the analysis results, we proposed strategies for improving the safety standards, such as the use of advanced guard rails and wheel-attached outriggers, to enhance the safety and field applicability of the mobile scaffold. Technology development and improvements in the safety standards for the use of mobile scaffold will aid in the prevention of fatal accidents caused by mobile scaffold.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.88-91
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• 2007

Turnout system is a mechanical installation enabling trains to be guided from one track to another which is consists of point blades, common crossing and guard rail etc. These structural feature causes vibration, noise and damages while railroad car wheel is passes by. A tilting train is a train with a tilting mechanism that enables increased speed on regular railroad tracks. The aim of this paper is to study a characteristics of the shock-vibration and noise of tilting and existing train passes by turnout systems. To analyze and assesment, noise and vibration measurement was carried out at the Naesu-station of Chungbuk-line which equipped with cast manganese crossing and built-up crossing and Illo-station of Honam-line which equipped with cast manganese crossing.

• Journal of the Korean Society for Railway
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• v.8 no.1
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• pp.93-100
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• 2005

The turnout system is typical railway facility to be in the way of conventional railway line's speed-up. The KNR(Korean National Railroad) has a speed limit regulation (130km/h) for the passing the turnout to guarantee a safety. This research had been performed to confirm the propriety of this regulation by using experimental and analytical way before it was carried out. The reasonableness of the speed-limit regulation was judged base on the several experiments. It was proved that the regulation was not useless as it had been regarded and very important guide at least up to now.