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한국형 고속철도 차량의 운행조건에 따른 차내 소음 분석
최성훈(Choi Sunghoon),김재철(Kim Jae-Chul),이찬우(Lee Chan-Woo),문경호(Moon Kyung-Ho) 한국철도학회 2003 한국철도학회 학술발표대회논문집 Vol.- No.-
The conditions for measurement of the interior noise should meet the international standards. However, due to the limitations in test conditions the possible errors in measurement equipment, reliability of the measurement results has been questioned. Hence, the test procedure for the interior noise measurement of KTX vehicles are reviewed and investigated with the reference of international standards. Furthermore, the acceptable tolerance is inspected through the analysis of the factors that influence the interior noise of the KTX vehicle.
철도 차량의 소음원 측정을 위한 마이크로폰 어레이 설계
최성훈(Sunghoon Choi),노희민(Hee Min Noh),조준호(Jun-Ho Cho),고효인(Hyo-In Koh) 한국철도학회 2011 한국철도학회 학술발표대회논문집 Vol.2011 No.10
This paper deals with the design of a microphone array to measure location and spectral characteristics of railway noise sources. A microphone array estimates the direction of a noise source assumed as a point source using the delayed-sum beamforming method and its performance is determined in terms of resolution and side-lobe level. A 48 channel microphone array was already developed to measure noise sources of KTX trains and a new array with 96 microphones has been designed to enhance the performance. This paper simulates the performance the microphone arrays according to the configuration of microphones and verifies it through on-site tests.
최성훈(Choi Sunghoon),박춘수(Park Choon-Soo),이태형(Lee Tae-Hyung) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-
The first task for the development of a train system is to define the system and to determine its requirements. Reliability target is one of the requirements defined in the system requirements. In railway applications it is advised to follow the procedures given in IEC 62278 to fulfill reliability requirements. The reliability requirements are derived from the customer"s needs. The way in which the system requirements reflect the customer"s needs is strongly dependent on the characteristics of the product. In general the customer of commercial trains presents the system requirements from their needs. However, the relation between the customer and supplier is equivocal for a project to development a prototype train, and the reliability program should be different from that of an usual commercial project. This paper deals with the reliability management and assessment plan carried out for the on-going "Next generation high-speed train development project".
양극파형의 펄스폭 변화에 따른 피에조 구동형 잉크젯 노즐의 액적 토출 특성
최성훈(Sunghoon Choi),성재용(Jaeyong Sung),이명호(Myeong Ho Lee) 한국가시화정보학회 2012 한국가시화정보학회지 Vol.10 No.1
In this study, a piezoelectric inkjet nozzle with a rectangular shaped channel has been developed, and the characteristics of droplet formation have been investigated according to the variation of pulse widths in bipolar waveform. The channel of the nozzle was fabricated transparently by a precision machining technique. A tantalum membrane which was attached to a piezoelectric material covers the channel. By applying two types of bipolar waveforms to the piezoelectric actuators, droplet formation through the nozzle was monitored by a CCD camera. For the variety of the first and second pulse widths in the bipolar waveforms, the regimes of single and double droplet formations are presented. The change of droplet velocity which depends on the pulse width and the type of waveform is also discussed.
최성훈(Choi Sunghoon),은종필(Eun Jong-Pil),강동훈(Kang Donghoon) 한국철도학회 2009 한국철도학회 세미나자료 Vol.2009 No.5
Measurement of dynamic characteristics are widely used to detect defects in mechanical or civil structures. The most common approach is to measure changes in frequency spectrum or mode shapes using accelerometers. An alternative to using mode shapes is using stain modes. Strain is more sensitive to local defects than displacement, and hence stain modes measurement is an efficient in structural health monitoring. This paper deals with dynamic monitoring of a beam structure using strain sensors. Resistive strain gages and FBG strain gages are used and their characteristics are compared. It has been known that resistive strain gages are week to EMI environment and suffers from noise at high frequency range. It has been shown that the FBG sensor is a good alternative that overcomes such difficulties.