• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2009년도 춘계학술대회 논문집
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• pp.242-243
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• 2009

Friction stir welding and friction stir processing is a new solid state processing technique for ioining and micro..structural modification in metallic materials. It has been applied not only joining for light metals but also modification of the microstructure to enhance mechanical properties. In thin study, we investigated the mechanical properties for applied friction stir welding and processing under various parameters such as probe diameter, probe type, traveling speed and rotating speed for 5456-H116 AI allov. As a result of experiments, optimum condition of friction stir welding is traveling speed of 15mm/min, rotating speed of 500RPM at 6mm diameter probe. Moreover, in the case of friction stir processing, the optimum condition is traveling speed of 15mm/min, rotating speed of 250RPM at full screw probe. As above mentioned, the mechanical characteristics enhanced with the decreasing of traveling speed and the increasing of friction areas because of plastic flow due to high friction heat. These result can be used as reference data for ship repairment.

• 한국표면공학회지
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• 제41권6호
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• pp.341-350
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• 2008

In friction stir welding for 6061-T6 with various traveling speed and rotation speed conditions, the best mechanical characteristics presented in traveling speed of 507 mm/min and rotation speed of 1100RPM. The maximum tensile strength and yield strength increased with the increasing of traveling speed. The result of the electrochemical characteristic evaluation in friction stir welding at optimum conditions for 6061-T6 Al alloy presented a good characteristics compare to base metal.

• 대한산업공학회지
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• 제29권1호
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• pp.32-40
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• 2003

In this study, we develop the Genetic Fuzzy System(GFS) to estimate the link traveling speed. Based on the genetic algorithm, we can get the fuzzy rules and membership functions that reflect more accurate correlation between traffic data and speed. From the fact that there exist missing links that lack traffic data, we added a Case Base Reasoning(CBR) to GFS to support estimating the speed of missing links. The case base stores the fuzzy rules and membership functions as its instances. As cases are accumulated, the case base comes to offer appropriate cases to missing links. Experiments show that the proposed GFS provides the more accurate estimation of link traveling speed than existing methods.

• 한국강구조학회 논문집
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• 제8권3호통권28호
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• pp.47-54
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• 1996

Recently Sucessive progress in train technic has enabled us to constructed high-speed railways for ourselves. This caused more rapid train more pressure on a track and speedier track break-down. Especially in the construction of high-speed rails for high-speed traveling and safety accurate breaking distance is essential and not only computation of rolling resistance in theory but also verification through real measurement are important in basic material for breaking and starting load caused during the train running. In this study, we measured traveling resistance and calculated traveling resistance formula in the case of the SAEMA-EUL which consists of main part of current passenger trains and frights in this country.

• 한국초전도ㆍ저온공학회논문지
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• 제12권1호
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• pp.47-51
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• 2010

We already obtained magnetic behavior of superconducting Nb foil of linear type magnetic flux pump (LTMFP) by means of the FEM analysis. As well as, fundamental equations of pumping current were theoretically derived based on the pumping sequences according to the position of normal spot of the moving flux. In this paper, we experimentally investigated pumping performances of LTMFP with a wide range of traveling speed of magnetic field. In order to confirm the numerical and theoretical approaches, we explained the pumping characteristics of LTMFP by use of the calculation sequence of pumping current.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.334-338
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• 2004

KTX has started commercial service from Seoul to Busan and Mokpo since April 1, 2004. The service line is composed of new-high speed line and conventional line. Before KTX is runs, the maximum operational speed on conventional line was 140km/h. In order to reduce the traveling time, operation speed of KTX must be increased on the conventional line. So, we performed test running with prototype HSR-350x and verification of safety was made in $10\%$ speed-up. Korean High Speed Train HSR-350x) was developed by G7 - R&D project. In this study, in safety aspect, several technical reviews are introduced and the possibility for reduction of traveling time is investigated on the conventional line by using HSR-350x.

• 대한교통학회지
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• 제27권2호
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• pp.117-131
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• 2009

고속도로이용자가 주행할 때 도로기하구조를 정확하게 파악하지 못하면, 도로이용자는 자신의 감각과 인식에 의존해 판단을 내리게 되기 때문에 고속도로의 주행성을 평가할 때 설계자와는 다른 판단을 내리게 될 수도 있다. 따라서 도로이용자의 기대심리를 만족시키면서 안전성, 쾌적성 등을 확보하기 위해서는 정확한 주행속도를 예측할 필요가 있다. 또한, 고속도로의 기하구조적인 주행성뿐만 아니라 도로이용자가 이러한 구성요소의 조화에 의해 느끼는 감성적 측면에서의 주행환경만족도에 대한 인식의 변화를 파악할 필요가 있다. 이에 본 연구에서는 주행속도 예측모형 구축하기 위해 6개 고속도로(경부, 서해안, 영동, 남해, 중앙, 호남)를 대상으로 주행속도에 영향을 미치는 요인을 크게 선형요소, 교통운영특성 요소로 분류하였다. 주행속도에 영향을 미치는 요인을 대상으로 다중회귀를 이용한 주행속도예측모형 구축 및 검증 결과, 통계적으로 모두 적합한 것으로 나타났다. 또한, 본 연구에서는 고속도로 이용자를 대상으로 개별면접 설문조사를 통해 수집된 주행환경만족도 이미지 데이터를 바탕으로 수량화 제II류 및 주성분분석을 실시하여 고속도로 주행환경만족도에 대한 영향 요인을 규명하였다. 또한 수량화 제I류 및 구조방정식을 이용하여 사회인식 및 고속도로 이용자의 실제인식의 변화가 고려된 고속도로의 주행환경만족도 모형을 구축하였다. 본 연구에서 구축된 모형을 통해 주행속도와 같은 정량적인 요인뿐만 아니라 도로이용자가 느끼는 고속도로의 주행환경만족도와 같은 정성적인 요인에 대한 결과도 제시할 수 있어서 도로이용자가 느끼는 변화된 교통 환경과 인식여부가 반영된 고속도로의 주행성을 평가할 수 있다는 데에 그 의의가 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1614-1621
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• 2008

I accomplished a curve section traveling safety assessment analysis followed with railway condition for elevation of a curve passage speed of train utilizing trail analysis model. As a result, we confirmed that excess cant influence in badly traveling safety of train followed with cant change and cant shortage influence in badly traveling safety in case of large a curve radius and traveling safety of originally a curve section is most wrong. Also we confirmed that shortage of relief a curve length influence in badly traveling safety followed with change of relief a curve length.

• ETRI Journal
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• 제34권6호
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• pp.942-945
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• 2012

A high-speed traveling-wave photodetector (TWPD) with an InGaAs absorber is designed and realized. The bandwidth of the TWPD is measured using electro-optic sampling techniques. The bandwidth is 410 GHz, which shows that the RC limitation is overcome. While the TWPD shows a low responsivity of 0.06 A/W at 1,550 nm, this value can be improved through further optimization of the structure without a sacrifice in bandwidth.

• Smart Structures and Systems
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• 제24권2호
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• pp.183-191
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• 2019

A piezoelectric paper feeder actuator using Micro Virtual Roller (MVR) is proposed, designed, fabricated and tested. This actuator can drive a sheet of paper forward or backward without any mechanical parts, such as the costly and heavy rollers used in traditional paper feeders. In this paper feeder actuator, two vibrating stators which produce traveling waves are used to drive the paper. The vibrations of the stators are similar to those of piezoelectric motors and follow a similar procedure to move the paper. A feasibility study simulated the actuator in COMSOL Multiphysics Software. Traveling wave and elliptical trajectories were obtained and the dimensions of the stator were optimized using FEM so that the paper could move at top speed. Next, the eigenfrequencies of the actuator was determined. Experimental testing was done in order to validate the FEM results that revealed the relationships between speed and parameters such as frequency and voltage. Advantages of this new mechanism are the sharp decrease in power consumption and low maintenance.