Static and Dynamic Behavior of Disk Bearings under Railway Vehicle Loading

오세환,최은수,정희영,김학수,Oh, Saeh Wan,Choi, Eun Soo,Jung, Hie Young,Kim, Hak Soo Korean Society of Steel Construction 2006 韓國鋼構造學會 論文集 Vol.18 No.4

본 연구의 목적은 철도차량하중으로 인한 디스크받침의 정 동적 거동특성을 평가하여, 디스크 받침 설계기술 발전에 기여하고자 함이다. 디스크받침은 탄성받침의 일종으로 폴리우레탄 패드를 사용하여 탄성을 구현하고 있으며, 가동단에는 PTFE를 사용하여 교량의 움직임을 흡수하고 있다. 실험실에서 수차례의 정적 실험을 실시하여 폴리우레탄 고무의 정적거동을 평가하기 위한 데이터를 획득하였다. 또한, 4개의 디스크받침은 철도교량인 판형교에 설치하여 철도차량에 의한 디스크받침의 동적 거동을 측정하였다. 현장실험은 기관차 1량을 사용하여 일정속도로 주행하는 주행시험을 실시하여 각 디스크받침의 동적 변형과 이에 작용하는 동적 하중을 측정하였다. 정적 실험을 통해서 나타난 사실은 수직강성에 크게 기여하는 것이다. 또한 동적 강성은 정적으로 평가된 강성보다 크게 나타났다. 차량의 속도가 증가함에 따라 디스크받침의 변형도 증가하는 것으로 나타났지만, 크게 증가하지는 않았다. 디스크받침의 고정단의 동적 강성이 가동단의 강성보다 크게 나타나는데, 이는 가동단의 PTFE가 변형을 일으키기 때문이라고 판단된다. 이러한 결과는 철도교를 위한 디스크받침 설계기술의 발전에 기여할 것이다. The goal of this study is to ases the static and dynamic behavior of disk bearings under railway vehicle loadings. Several static tests were conducted in a laboratory t bearings, all having the same kind of polyurethane disk as used in the static tests, were installed under a full-sized railway bridge and tested with a running locomotive, the tests results, the static and dynamic stiffness of the disk bearings were estimated and compared. the deformation of the disk bearings under the bridge was measured at varying disk bearing was almost half of that under dynamic loading. In addition, the dynamic stiffness of the fixed disk bearing was 80% higher than that of an expansion disk bearing, since the PTFE in the expansion bearing is displaced. The deformation of the disk bearing did not vary significantly with changes in locomotive's speed. The results of this study can contribute to fast-tracking the formulation of a design technique for disk bearings for railway bridges.

The Effects of Social Media on Music-induced Tourism: A Case of Korean Pop Music and Inbound Tourism to Korea

오세환,안중호,백현미 한국경영정보학회 2015 Asia Pacific Journal of Information Systems Vol.25 No.1

With the rapid spread of social media, video-sharing social media like YouTube has emerged as a consumption and distribution channel for entertainment goods such as music videos and movie trailers. In tourism research, there has been a lot of research of how the visual media such as movies and soap operas induced tourism. However, no studies have attempted to examine the role of social media as a music consumption channel and its impact on tourism. Expanding a body of media-induced tourism, we analysed the impact of video-sharing social media on music-induced tourism with a case of Korean pop music and inbound tourism to Korea. Developing a Web-crawler, we collected YouTube users’ comments data on 166 Korean pop music video clips which were released from 2009 to 2012 with over 1 million view counts. Controlling many of the determinants of tourism and analysing country-by-country impact of YouTube comments with the panel data, we found that engagement of Korean pop music video clips on YouTube is a significant predictor for the flow of inbound tourists to Korea.

植物凝集素 Enonymus europaeus B.의 免疫血淸學的 性狀에 關한 硏究

吳世煥 大韓法醫學會 1991 대한법의학회지 Vol.15 No.1

Extracts of ground seeds of E. europeaeus B. were prepared in the usual manner, thereafter the agglutination test with human red blood cell, absorption test, agglutinatio titration test, agglutination titration test with ficinated red blood cells, and agglutination inhibition test with various sugar solutions were carried out. As a result, author demonstrated that the certain red blood cells were agglutinated by E. europeaeus B. extracts but the others were failed, a series of 349 red cells was tested and revealed that 132(37.82%) was positive and 217 (62.28%) was negative and same results also can be observed in group b red blood cells. Agglutinations of E. europeaeus extracts with ficinated red blood cells were markedly enhanced agglutination reactivity without relation to any blood group, and agglutinations of E. europaeus B. extracts with human red blood cells were not inhibited by various sugar solutions.

비료의 일관 파렛트화 추진계획

오세환 한국파렛트컨테이너협회 1997 파렛트 뉴스 Vol.3 No.-

크라우드펀딩 성공요인에 대한 탐색적 비교 연구: 한국, 미국, 일본 플랫폼을 중심으로

오세환 한국정보시스템학회 2018 情報시스템硏究 Vol.27 No.4

Purpose The purpose of this paper is to conduct exploratory comparative research on the determinants of successful crowdfunding projects, focusing on multiple crowdfunding platforms in Korea, U.S., and Japan. Design/methodology/approach This study collected data from three representative crowdfunding platforms: Wadiz (Korea), Kickstarter (U.S.), and Readyfor (Japan). Based on 1,906 crowdfunding projects from Wadiz, 3,864 projects from Kickstarter, and 3,060 projects from Readyfor, multiple regression models were applied. Findings Focusing on the crowdfunding projects which have overly achieved goal amount, the analysis results show that the number of comments, the number of Facebook likes and the number of backers have an positive impact on the performance of crowdfunding projects, while target amount has a negative impact. Comparatively, word counts of project description have an impact on funding performance in U.S. and Japan, while the number of images in project description affects funding performance in Korea and U.S. Meanwhile, video clips in project description has little impact on crowdfunding performance in all of the three funding platforms.

한, 미, 일 크라우드펀딩 성공요인에 대한 탐색적 비교 연구

오세환 한국무역학회 2018 한국무역학회 세미나 및 토론회 Vol.2018 No.12

Ni, Co 산화물 고용체가 분산된 CNT로 이루어진 다공성 노른자-탄소껍질 구조체 합성

오세환,조중상 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.1

경제 불확실성과 한국 기업의 투자 - 한국 미국 중국 경제 정책 불확실성 지수를 활용한 실증 연구 -

오세환,노성호 한국동북아경제학회 2022 동북아경제연구 Vol.34 No.3

This study investigates the effect of economic uncertainty on firm investment. 67,128 observations from 2006 to 2017 of 5,594 Korean firms from the Business Activity Survey and economic policy uncertainty (EPU) indices of Korea, the United States, and China are used as data. The long-term cointegration relationship between firm sales and capital stock is confirmed, and the hypothesis that economic uncertainty affects firm investment along with demand is verified through an error correction model. In particular, Korean firms with subsidiaries in the US and China are analyzed separately to investigate the effect of the US and Chinese EPU. According to the analysis, Korean firms show a short-term reduced response to irreversible investment, so that the coefficient of influence of the square term of the change in sales on the change in firm investment shows a positive coefficient (a convex type of firm investment response). In addition, economic uncertainty affects firm investment through interaction with sales change (the cautionary effect). In particular, the cautionary effect was more significant and clear when China’s economic uncertainty was taken as an independent variable.

4차 산업혁명 기술 활용이 수출성과에 미친 영향

오세환 한국무역학회 2021 貿易學會誌 Vol.46 No.2

With the advent of the 4th Industrial Revolution, there is a rising interest in the impact of these changes on Korea's trade. While the previous studies related to the 4th Industrial Revolution are very limited in the field of trade research, this study attempts an empirical analysis regarding the effect of the use of the 4th Industrial Revolution technology on the performance of exporters, based on the data of the Survey of Business Activities during 2017-2019 by the Korean government statistical office. Through the empirical analysis in combination with the propensity score matching (PSM) and the difference-in-difference (DID) analysis, this research confirms that the use of the 4th Industrial Revolution technology has a positive effect on the export performance of Korean exporters.

철도교용 고무패드의 강성 추정기법

오세환,최은수,정희영,Oh, Saeh Wan,Choi, Eun Soo,Jung, Hie Young 한국강구조학회 2005 韓國鋼構造學會 論文集 Vol.17 No.3

본 연구에서는 철도교량에 교량받침으로 사용될 수 있는 4종류의 고무패드의 사용상의 특성을 분석하고, 강성과 감쇠비를 결정하기 위한 방법을 제시하였다. 고무패드의 강성을 결정하기 위해서는 정적 실험을 통한 직접적인 방법과 동적 실험을 통한 간접적인 방법이 가능하다. 본 연구에서 두 가지 방법에 의해서 고무패드의 강성을 평가하고 비교하였다. 고무패드의 감쇠비는 동적 실험에 의해서만 파악이 가능하며 폴리우레탄 고무의 경우 천연고무나 크로로프렌 고무와 유사한 감쇠비를 가지는 것으로 나타났다. 폴리우레탄 고무는 천연고무나 크로로프렌 고무에 비해 경도가 크기 때문에 작은 면적으로도 큰 하중을 견딜 수 있으며, 또한 같은 형상계수를 가지는 패드에서도 더 큰 강성을 보여 철도교의 교좌로서 활용성이 더 큰 것으로 판단되었다. 천연고무나 크로로프렌 고무 패드는 수직하중에 의한 수평 변형이 크게 발생하는데 비해, 폴리우레탄 고무패드는 수직하중에 의한 수평방향의 변형이 거의 발생하지 않기 때문에 보강재에 의한 보강이 필요하지 않다. This study analyzed the characteristics of four kinds of bridge rubber pads and suggested a method of determining the stiffness and the damping ratio of the pads.The stiffness of rubber pads can be estimated by a direct static test and a dynamic test indirectly.This study used both methods to determine the pad's stiffness.The damping ratio of pads can be obtained using the dynamic test and the damping ratio of polyurethane rubber pads was estimated to aproximate that of natural and chloroprene rubber pads.The polyurethane rubber pads are harder than natural and chloroprene rubber pads and thus carry larger load bearing capacity.In addition, they showed higher stiffness with the same shape factor than the others and thus are more available for bridge bearings.Although natural and chloroprene rubber pads are elongated to large deformation in the horizontal direction due to vertical loads, polyurethane rubber pads almost do not generate horizontal deformation due to vertical loads regardless of the thickness and hardness of the pads.Therefore, they do not need reinforced plate to restrict horizontal deformation.