• 한국철도학회논문집
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• 제13권4호
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• pp.376-381
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• 2010

본 연구에서는 주요 간선 철도 노선의 고속화 시 열차풍 예측을 위하여 KTX 열차, 누리로 열차 및 TTX 열차를 대상으로 호남선과 경부선에서 Kiel-probe를 이용한 열차풍 측정 프루브 어레이와 다채널 압력측정 시스템을 이용하여 열차풍 현장 측정 시험을 수행하였다. 시험 결과, 열차가 통과하는 동안의 열차하부 평균유속을 열차의 속도로 나눈 값은 열차 속도에 무관하고 차량의 종류에만 관계하기 때문에, 주어진 열차의 종류와 열차 속도에 대하여 열차 하부의 유속을 예측할 수 있는 것으로 나타났다. 또한 열차 하부 형상과 하부 열차풍특성의 관계에 대해서도 논하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1511-1515
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• 2004

Machine vision system plays an important role in factory automation. Its many applications are found in automobile manufacturing industries, as an eye for robotic automation system. In this paper, an automobile position measuring vision system(APMVS) applicable to manufacturing line for under body painting of a car is introduced. The APMVS measures position and orientation of the car body to be sealed or painted by the robots. The configuration of the overall robotic sealing/painting system, design and application procedure, and application examples are described.

• 오토저널
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• 제14권6호
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• pp.99-104
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• 1992

The complex geometry of the engine room of a passenger car has been modelled two-dimensionally and the thermal and fluid flow therein have been analyzed by using a commercially available code, PATRAN/FLORAM$\mid$N. FLOTRAN adopts a finite element method with streamline upwind formulation for convective terms and the k-.epsilon. turbulence model to solve the three dimensional turbulent flow and heat transfer problems. Velocity vectors, pressure and temperature distributions have been obtained for various cases with different arrangements of license plate, underbody-covers and air dams. The results show that the numerical analysis using PATRAN/FLOTRAN can predict qualitatively well the practical phenomena.

• Journal of Mechanical Science and Technology
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• 제14권11호
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• pp.1267-1275
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• 2000

A series do wind tunnel tests were conducted for Korean high-speed train model with various shape components to assess the contributions to aerodynamic drag. In order to elucidate the ground effects, two different wind tunnels, one with a moving ground system and the other with a fixed ground, were used for the same model and the results of both were compared and analyzed in detail. The result show that a suitable ground simulation is necessary for the test of a train model with many cars and detailed underbody. But the relative difference of the drag coefficients for the modifications of shape components can be measured by a fixed ground test with high accuracy and low cost. The effects of the nose shape, the inter-cargap and the bogie-fairing on total drag were discussed and some ideas were prosed to decrease the aerodynamic resistance of high speed train.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.356-360
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• 2007

Fuel sloshing in a vehicle fuel tank generates a reluctant low frequency noise, called slosh noise. To reduce slosh noise, whilst many approaches have used the Computational Fluid Dynamics method to first identify fuel behavior in a fuel tank, this paper applies the Transfer Path Analysis method. It is to find contribution of each transfer path from noise transfer function, vibration transfer function and acceleration. Then the final goal is to attenuate slosh noise by controlling them. To this aim, two types of models are studied. One is the decoupled model in which some of connection points of the fuel tank with the vehicle underbody are separated. The other is the modified model which is created by changing noise transfer function and acceleration from the original model. The analysis and validation test results show that the transfer path analysis can be an approach to enhancing slosh noise.

• 한국산업융합학회 논문집
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• 제3권1호
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• pp.29-36
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• 2000

In order to reduce a aerodynamic drag of the rear, body, effects of rear lower end configuration of a vehicles were investigated by measuring the pressure distribution, visual flow phenomena by the use of digital image processing technique. The use of flow visualization in recent years has improved the general understanding of structure of complex flow and has yielded valuable information for analyzing fluid flow. As the results, it was found that the shape of rear lower part vehicles not only effected on the pressure distribution of the rear part of the vehicle but also difference of the flow phenomena.

• 오토저널
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• 제5권2호
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• pp.56-63
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• 1983

The aerodynamic characteristics of the most popular car (PONY 2) produced in Korea have been experimentally investigated by Seoul National University's wind tunnel. The model (PONY 2) chosen for the wind tunnel was a 1/5 scale of the original car without simulated underbody, cooling air flow and accessories. The measured aerodynamic drag coefficient corrected by JARI formula is 0.45 which is very close to those of small foreign cars. To see the effect of the different configurations on the aerodynamic drag, the modifications have been made by changing the hood slope and backlight slope, and putting the add-on-aerodynamic devices on the orignal shape. The rear spoiler was found the most effective one to reduce the aerodynamic drag. It may be concluded that the considerable aerodynamic drag reduction can be achieved by changing the slopes and A-O-A devices at the proper places of the car.

• 한국소음진동공학회논문집
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• 제17권8호
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• pp.766-770
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• 2007

Fuel sloshing in a vehicle fuel tank generates a reluctant low frequency noise, called slosh noise. To reduce slosh noise, whilst many approaches have used the Computational Fluid Dynamics method to first identify fuel behavior in a fuel tank, this paper applies the Transfer Path Analysis method. It is to find contribution of each transfer path from noise transfer function, vibration transfer function and acceleration. Then the final goal is to attenuate slosh noise by controlling them. To this aim, two types of models are studied. One is the decoupled model in which some of connection points of the fuel tank with the vehicle underbody are separated. The other is the modified model which is created by changing noise transfer function and acceleration from the original model. The analysis and validation test results show that the transfer path analysis can be an approach to enhancing slosh noise.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2007년 추계학술발표대회 개요집
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• pp.199-202
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• 2007

The center floor is a part of underbody of cars. The assembling method is mostly a resistant spot welding. But the resistant spot welding has many demerits in productivity such as low welding speed, large spatter occurring, hard to verify the welding quality. The laser welding has many merits such as high welding speed, high static and dynamic weld strength. So the laser welding has been studied to substituted the resistant spot welding. Therefore, in this study, as a pre-evaluation stage for replacing the resistance spot welding with laser in production of automobile parts, the weldability of cold rolled and zinc coated steel sheets is studied and also evaluated the weld strength by the tensile shear test. And the shape of weld bead appearances and micro structure of the weld bead section is also evaluated.

• International Journal of Reliability and Applications
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• 제10권1호
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• pp.1-15
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• 2009

Even though the impact of manufacturing quality to reliability is not considered much as well as that of design area, a major cause of an early failure of the product is known as manufacturing problem. This research applies two different types of neural network algorithms, the Back propagation (BP) algorithm and Learning Vector Quantization (LVQ) algorithm, to identify and classify the nonrandom variation pattern on the control chart based on knowledge-based diagnosis of dimensional variation. The performance and efficiency of both algorithms are evaluated to choose the better pattern recognition system for auto body assembly process. To analyze hundred percent of the data obtained by Optical Coordinate Measurement Machine (OCMM), this research considers an application in which individual observations rather than subsample means are used. A case study for analysis of OCMM data in underbody assembly process is presented to demonstrate the proposed knowledge-based pattern recognition system.