• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.339-342
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• 2008

The gearbox for wind turbine has been increased the size by demanding of bigger power production. The optimal sizing for gearbox is demanded because of limited space on the nacelle. The volume and weight for the gearbox are influenced especially for size of it. Therefore, the purpose of this study investigates the design characteristics using flexible pin of gearbox for minimizing the volume and weight of the gearbox.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.539-544
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• 1997

Although the identification of a moving noise source is important in reducing the source power of the transport systems such as airplane or high speed train, the direct measurement of the frequency characteristics is usually difficult due to wind noise when using a microphone running with that noise source. On the other hand the motion of a source causes the frequency characteristics of the pass-by sound measured at a fixed point to be distorted that it is quite difficult to identify the original source characteristics. In this study the relationship between the spectra of the source and the pass-by sound signal is analyzed for a source moving at a constant velocity. The effects of the speed and the frequency characteristics of the source on the pass-by noise spectrum are investigated through numerical simulations.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.364-369
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• 2012

The vehicle sound classified into driving sound due to power-train, operating sound due to electric motor like sunroof, door lock and electronic sound. These vehicle sound has various features depend on the characteristic of sound that user required. And it based on cultural and regional difference of user. In this study, the user required vehicle sound characteristics for luxury sedan was investigated in overall viewpoint. And virtual target sound was developed through the result of user preference investigation. Next, Jury test was carried out in Germany, USA and Korea for evaluating the target sound. And the regional and individual difference of preference was analyzed through the result of jury test. This result of research will be contributed to design of vehicle sound quality and target sound setting.

• 한국자동차공학회논문집
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• 제5권3호
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• pp.106-116
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• 1997

In this paper, using MATLAB SIMULINK, a generalized design methodology was suggested for multi pass transmission(MPT) by classifying the vehicle power train as prime mover, MPT and vehicle dynamics. This approach enables a designer to investigate the influence of each transmission component by simple combination of system components without changes of overall program. Using the design methodology, a MPT consisting of CVT, 2, clutches and reduction gears was designed for a braking energy regenerative flywheel hybrid vehicle. The CVT is essential in order to connect the engine and flywheel speed with the vehicle speed. For the purpose of smooth clutch operation, control algorithm was suggested by introducing dead zone for the clutch engagement. Using the SIMULINK model, performance of the flywheel hybrid vehicle with MPT was investigated. It was observed from the simulation results that the MPT vehicle showed better fuel economy, 47% than that of AT vehicle, 27% than that of CVT vehicle for ECE-15 driving cycle. Especially destinct fuel efficiency improvement was obtained for city driving cycle requiring more frequent stop and start.

• Nuclear Engineering and Technology
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• 제29권3호
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• pp.211-217
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• 1997

Adverse effects caused by the surveillance test for the components of nuclear power plant involve plant transients, unnecessary wear, burden on licensee's time, and the radiation exposure to personnel along with the characteristics of each component. The optimization methodology of STI and AOT has been developed and applied to AFWPs of a reference plant. The approach proposed in this paper consist of the resole in minimal mean unavailability of the two-out-of-four system with adverse effects are analytically calculated for the example system. The surveillance testing strategy are given by the sequential test, the staggered test and the train staggered test which is a mined test scheme. In the system level, the sensitivity analyses for the STI and AOT, are performed for the measure of the system unavailability of the top event in the fault tree developed for the example system. This methodology may contribute to establishing the basis for the risk-based regulations.

• Journal of the Optical Society of Korea
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• 제3권2호
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• pp.51-54
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• 1999

A Nd:YLF laser has been actively mode-locked at the third-order harmonic cavity frequency using a lithium niobate phase modulator. Self-oscillating pulses of 14 ps duration, 1 GHz repetition rate, and 10mV average power at 1053 nm wavelength have been obtained. A 1GHz rf signal to drive a phase modulator was obtained by using 1GHz pulse train without rf synthesizer as a driver of an active mode locker.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 춘계학술대회 논문집
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• pp.176-184
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• 1999

Dynamic characteristics of pantograph-catenary system that supplies electrical power to high-speed trains are investigated. A simple catenary is composed of the contact and messenger wires connected by hamgers possessing bi-directional stiffness properties. The influences of parameters that determine the contact properties of pantograph-catenary system are investigated through numerical simulations. For the catenary, a finite difference model composed of 10 spans is constructed. The contact and messenger wires are modeled as strings with respective tension and damping ratio values. The pantograph is modeled as a linear 3-degree-of-freedom system. It is found that the tension, number of hangers and damping ratios as well as the speed of the train significantly influence the contact forces and contact separation rate

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 춘계학술대회 논문집
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• pp.95-102
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• 1999

Because a driver is located in the front end of KHST, he is most likely to be insured at collision accidents. So, it is very important to design some survival space for the driver. To evaluate the driver's safety of KHST (Korean High Speed Train), the front structure of power car is analysed using PAMCRASH under the SNCF accident scenario(collision against a movable rigid mass 15 ton at 110㎞/h). Because the driver's cab of KHST is a modified version of TGV-K, which is not so strong as to protect him, it turns out to be inadequate to guarantee his survival space. Therefore it is recommended to redesign the driver's cab in a crashworthy point of view like the case of TGV-Duplex or NEC.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.299-304
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• 2008

Catenary and Pantograph are a power supply devices for electric trains and shall be steadily contacted. Rail catenary must be installed precisely and managed for stable train operations. But external factors such as weathers, nature, etc., or aging affect catenary geometry. Changed catenary height causes high voltage spark or instant electric disconnection. Big spark and disconnection damage pantograph shoe and catenary coating and might interrupt rail operations. To prevent a big scale spark or electric disconnection catenary maintenance shall be required with catenary geometry measurement systems. In this paper, we describe the development of catenary height and stagger measurement system. The catenary height and stagger measurement system uses Acuity company's AR4000 Range Finder for distance measurement and AccuRange Line Scanner for degree measurement. This system reports suspicious overhead line sections with excessive height and stagger variance.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.742-747
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• 2008

This paper is described the systematic activities of RCM to improve the availability for AREX railway system. The purpose of these activities are to maintain and enhance the reliability, availability, maintainability and safety, and to implement the effective maintenance for electrical and mechanical system including rolling stock, signalling, telecommunication, power supply, overhead catenary and platform screen door with impact to train operation.. The main activities consist of systematic failure and repair recording by integral information system, analysis and corresponding countermeasure. As applying these activities in opeartion and maintenance works, the availability of AREX railway system is going on improvement gradually, and maintenacne works are improved with these results.