• International Journal of Korean Welding Society
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• v.3 no.1
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• pp.2-7
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• 2003

Laser welding application for car body manufacturing has many advantages in the stiffness and the lightness of vehicle, the productivity of assembly line, and the degree of freedom in design. This presentation will express the innovation of car body manufacturing including parameter optimization, process modeling, and system integration. In this application the investment for systems was cut down dramatically by real time switching over the laser path between two welding stations. Points of technical discussion are as follows; optimization of parameters such as laser power, robot speed and trajectory, compact and useful design of jig & fixture to assure welding quality for 3 sheet-layer zinc-coated steel, system integration between 4㎾ Nd:YAG laser device and the other systems, on-line real time welding quality monitoring system, perfect safety standards for high power laser, minimization of consumption costs such as arc lamp, protective glass for optic, etc. This application was successfully launched mass production line in 2001. The laser-welded line of side panel consists of 122 stitches totally. And the length is about 2.4m.

• International Journal of Automotive Technology
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• v.5 no.4
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• pp.297-302
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• 2004

This paper presents the low cycle thermal fatigue of the engine exhaust manifold subject to thermo-mechanical cyclic loading. As a failure of the exhaust manifold is mainly caused by geometric constraints of the less expanded inlet flange and cylinder head, the analysis is based on the exhaust system model with three-dimensional temperature distribution and temperature dependent material properties. The result show that large compressive plastic deformations are generated at an elevated temperature of the exhaust manifold and tensile stresses are remained in several critical zones at a cold condition. From the repetition of these thermal shock cycles, maximum plastic strain range (0.454%) could be estimated by the stabilized stress-strain hysteresis loops. It is used to predict the low cycle thermal fatigue life of the exhaust manifold for the thermal shock test.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.1
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• pp.41-45
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• 2012

Until now, most studies of foot moving or driving posture have been performed under laboratory driving conditions. But there are many different things between actual driving conditions and laboratory driving conditions because, in laboratory conditions, it is hard to consider vehicle's noise, vibration and people's psychology state while driving. Thus this study is performed through actual driving conditions. And while driving test, we recorded driver's foots with 2 cameras to investigate foots(left and right) heel point and how human foots move to control the three pedals : accel, brake and footrest.. Through driving test, the results of this study show that the position of driver's heel point isn't related to stature and tends to be generalized.

• Journal of the Korean Society for Heat Treatment
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• v.17 no.2
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• pp.73-77
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• 2004

The efforts which increase the strength of the auto-body structure and decrease its weight lead to develop a new concept of part production systems, such as Post-Form Strengthening by induction heat treatment. In this study, several cold and hot-rolled sheet steels were used to find out optimum induction heat treatment conditions. After induction heat treatment, strength of heat-treated sheet steels was increased significantly compared with that of as-rolled steels. From these results, auto-body structure which has more light and safe has been made by using this induction hardening method.

• 한국어정보학회:학술대회논문집
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• 2017.10a
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• pp.194-196
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• 2017

기존의 단어 기반 접근법을 이용한 개체 연결은 단어의 변형, 신조어 등이 빈번하게 나타나는 비정형 문장에 대해서는 좋은 성능을 기대하기 어렵다. 본 논문에서는 문서 임베딩과 선형 변환을 이용하여 단어 기반 접근법의 단점을 해소하는 개체 연결을 제안한다. 문서 임베딩은 하나의 문서 전체를 벡터 공간에 표현하여 문서 간 의미적 유사도를 계산할 수 있다. 본 논문에서는 또한 비교적 정형 문장인 위키백과 문장과 비정형 문장인 소셜 미디어 문장 사이에 선형 변환을 수행하여 두 문형 사이의 표현 격차를 해소하였다. 제안하는 개체 연결 방법은 대표적인 소셜 미디어인 트위터 환경 문장에서 단어 기반 접근법과 비교하여 높은 성능 향상을 보였다.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.325-329
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• 2004

본 논문은 하이브리드 전기자동차의 12V보조배터리 충전용 DC-DC 컨버터의 최적설계에 관한 것으로 하이브리드 전기자동차의 특성상 DC-DC 컨버터는 최대부하의 $30\%\~70\%$ 정도의 비교적 낮은 부하영역에서 주로 동작하므로 이에 따른 적절한 설계가 요구된다. 따라서 DC-DC 컨버터의 주 동작영역에서 효율이 높도록 주요 설계요소인 스위칭 주파수와 고주파 변압기의 누설인덕턴스를 적절히 선정하고 코아의 윈도우 면적을 최소화하는 최적설계에 관한 연구이다.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.786-788
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• 2001

The use of permanent magnet motors have increased as controlled motors throughout the world. According to the development of magnetic materials and control technology, the motors are required to small size and compact design. Therefore it is introduced for servo motor to be contented with the characteristics of CNC machine tools in this paper. It is represented for the result of design, analysis, manufacture and test of the motor.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.393-396
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• 2001

차량 주행시 발생되는 소위 mimic 소음은 접이식 outside mirror의 접합부에서 발생하는 이음(異音)으로서 예민한 승객에게 지적된다. Mimic 소음은 2kHz이 상의 고주파 영역에서 특정 대역에 간헐적으로 발생하는 소음이며, 시간에 대해 앙상블 에버리지를 하는 일반적인 분석 방법으로는 나타나지 않는다. 그러나 주의 깊은 청취에 의해 그 존재를 분명히 느낄 수 있으므로 다꾸찌 시험 계획법에 의거 실험 샘플을 제작하여 녹음한 뒤, 청음 평가를 통하여 개선하는 과정을 거쳤다. 분석 결과 mimic 소음은 folding gap의 폭보다는 균일도를 유지하는 것이 중요하며, gap내의 공동(공동, cavity)을 메워 주는 것이 효과적이라는 결론을 얻었다.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.113-119
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• 2012

CTBA(Coupled Torsion Beam Axle) has been adapted as the rear suspension of a compact car. Because that has the advantage of cost and weight in comparison with multi-link type. But CTBA has the disadvantage in vehicle stability to become oversteer occurring toe-out of the rear wheel when cornering and braking. In this study, we suggested CTBA Geometry Compensation System to overcome the disadvantage of CTBA. We predicted braking and cornering vehicle performance from proposed equation and numerical simulation. And also, the results were compared to objective and subjective evaluation in vehicle.

• International Journal of Automotive Technology
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• v.3 no.2
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• pp.57-62
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• 2002

It is well known that the entrained air in oil causes appreciable reduction in the stiffness of hydraulic systems. It makes the response delay of the systems and sometimes destroys the stability. Because the hydraulic systems of automatic transmissions are operated in relatively low pressure and high temperature, it is very important to analyze the effects of the air included in automatic transmission fluid. However, it is difficult to derive the generalized model to describe the effective bulk modulus theoretically or measure it in actual operating conditions of automatic transmissions. This paper reviews previous studies of the air effects in hydraulic systems and the measurement techniques of the effective bulk modulus in operating conditions. Based on this work, the theoretical model with moderate complexity and the measurement technique of the effective bulk modulus considering entrained air effect at real operating conditions are suggested. Our paper also shows that the quantity of the entrained air in the automatic transmission fluid can be estimated from the experimental results.