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유형선,권혁수,윤성호 한국철도학회 1999 한국철도학회논문집 Vol.2 No.2
Two representative types of the AGT (Automated Guideway Transit) system, which are bogie and steering types, are available for the side-guided system. Each system primarily consists of the bogie frame, suspensions, wheelsets and axles, braking system and transmission system. Among these components, the bogie frame is one of the most significant components subjected to the whole vehicle and passenger loads. This paper describes structural analyses and associated fatigue analyses for each bogie frame depending on the various loading conditions on a basis of the railway vehicle code UIC 515-4. Subsequently, comparisons are made between those two types to estimate which type is more reliable in terms of strength and fatigue. It is observed that the bogie type is a little advantageous over the steering one from the strength analysis. However, the two types are found to be in a reliable range of fatigue even though a realistic fatigue load case is further carried out. In addition, an optimal size of thickness is suggested for designs of the bogie frame.
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유형선,편수범 한국철도학회 1999 한국철도학회논문집 Vol.2 No.3
In this paper, made was a study on a mesh generation method based on the pollution error. This method is designed for the control of the pollution error in any patch of elements of interest. It is a well-known fact that the pollution error estimates are much more than the local one. When the pollution error is significant, nothing can be said about the reliability of any estimator based on local computations in the patch. Reliable a posteriori error estimation is possible by controlling the pollution error in the patch through proper design of the mesh outside the patch. This design is possible by equally distributing the pollution error indicators over the mesh outside the patch. The mesh generated from the conventional feedback pollution-adaptive mesh generation algorithm needs many iterations. Therefore, the solution time is significant. But the remeshing scheme in the proposed method was used here. It was shown that the pollution-adaptive mesh improves the E.I., simply denoted as Effectivity Index, on the patch of interest, and the pollution error reduces less than the local error.
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유형선,윤성호,변상윤,편수범 한국철도학회 2000 한국철도학회논문집 Vol.3 No.3
The rubber wheel-type AGT has two major kinds of bogie; one is the bogie type and the other steering one. Both are important vehicular structure to support the whole running vehicle and passenger loads. This paper deals with the static analysis for the two types of bogie frame subjected to combined external forces, as well as independent ones specified in UIC 515-4. Furthermore, the dynamic analysis is performed under vibrational loading conditions so as to compare dynamic characteristics, Numerical results by using commercial packages, I-DEAS and NASTRAN show that maximum stresses do not exceed the yield strength level of material used for both bogies. From an overall viewpoint of strength, the bogie type turns out to be superior to the steering type except for the case of a lateral loading. It is also observed that the steering type shows a characteristics of low frequency behavior during a course of searching for structurally weak areas to be stiffened. The vibrational fatigue analysis for each bogie frame depends on the loading time history conditions which is applied. Time History Central Database List in the NASTRAN package. Subsequent1y, the fatigue life of bogie type is longer than the steering type.
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유형선 대한의용생체공학회 1985 의공학회지 Vol.6 No.1
A solution scheme for the squeeze film problem using the Newton-Raphson method with a tangential matrix is presented. The integration of elasticity equation is done with the aid of isoparametric elements and the film thickness under a sinusoidal load is obtained. A new squeeze-suction phenomenon which shoㅁvs the possibility oi maintaining fluid film under cyclic positive load conditions is observed for small load and Period and large compliance parameter cases. Thia could be an interesting result in applications like the viscous hydroplaning and the biological joints.
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혁신형 기업 인증 제도가 중소기업의 기술적 혁신 활동과 성과에 미치는 영향
유형선,전승표,김지희 한국기술혁신학회 2017 기술혁신학회지 Vol.20 No.4
In this study, the effectiveness of the innovative company certification system, which is one of the important means of the SME innovation promotion policies, was examined in terms of technological innovation activity and performance. To this end, we used the results of ‘SME Technology Statistical Survey’ conducted by the Small and Medium Business Administration and the Korea Federation of Small and Medium Business in 2013∼2015 to compare the innovative SMEs that have received the certifications such as Venture Certification, Innobiz Certification, and Mainbiz Certification with the general SMEs that did not. As a result, it was found that the innovative SMEs have comparative advantage in many detailed indicators related to the technological innovation activity and performance. However, the ratio of external use of R&D expenditure, the number of technology development attempts and the number of successes were not different according to the survey year, so it is necessary to strengthen the follow-up management of the system. On the other hand, the proportion of self-procurement R&D expenditure of the general SMEs was significantly higher than that of the innovative SMEs in all three-year surveys. Therefore, it is necessary to regulate the government funding for the innovative SMEs to be used as a complementary material, not as a substitute for their own R&D investment. In addition, the technological innovation activity and performance of a company were more influenced by the size of the company and the participating industry rather than by the certification, so it is necessary to consider it when establishing the technology innovation promotion policies. 본 연구에서는 중소기업의 기술혁신 장려 정책의 중요한 수단 중 하나인 혁신형 기업 인증 제도의 효과를 기술적 혁신 활동과 성과라는 측면에서 고찰하였다. 이를 위해 중소기업청과 중소기업중앙회에서 실시한 2013∼2015년 ‘중소기업 기술통계조사’ 결과를 이용하여, 벤처기업 확인, 이노비즈 인증, 메인비즈 인증 등 혁신형 기업 인증을 받은 혁신형 중소기업과 그렇지 않은 일반 중소기업을 비교하였다. 그 결과 혁신형 중소기업이 기술적 혁신 활동과 성과에 관련된 많은 세부 지표에서 비교 우위에 있는 것으로 나타났다. 그러나 외부사용 연구개발비 비중, 기술개발 시도건수와 성공건수 등은 조사년도에 따라 차이가 없는 것으로 나타나 본 제도의 사후 관리를 강화할 필요가 있는 것으로 판단된다. 한편 자체조달연구개발비 비중은 3개년 조사 모두에서 오히려 일반 중소기업이 혁신형 중소기업에 비해 유의미하게 높은 것으로 나타나, 혁신형 중소기업에 대한 정부의 자금 지원이 기업의 자체 연구개발 투자의 대체재가 아닌 보완재로 사용될 수 있도록 유인하는 제도적 장치가 필요할 것으로 보인다. 또한 기업의 기술적 혁신 활동과 성과는 인증 여부보다는 기업의 규모와 참여 업종에 더 큰 영향을 받으므로, 기술혁신 장려 정책 수립 시 이에 대한 고려가 필요할 것으로 판단된다.
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