• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.32-38
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• 2020

Cargo train braking uses the pressure changes in the air braking pipe to operate the braking tightening and releasing service repeatedly. Air-braking release failure means partial braking caused by a failure of the variable load valve after the driver handling the brake release. This phenomenon causes wheel flaws while driving a wagon, resulting in wheel breakage or train derailment. This study developed the air-braking release failure proof valve considering the technical requirements of the railway operation corporations. In addition, a durability test of the valve was carried out using a braking performance simulator, and its operating performance was evaluated from the pneumatic history under cyclic braking conditions. The warranty life of this valve was assessed by performing 160,000 cycles of testing of 12 prototypes in accordance with the zero-failure test method, considering the number of braking cycles while driving the wagon. During the durability test, the pneumatic input time, output time, and release velocity were almost constant. The warranty life of this valve was 59,860 times the 95% confidence level, which means that it can be operated without trouble for four years when the valve is installed in the bogie of the wagon.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.3
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• pp.337-342
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• 2011

Medical lift column controlling the vertical position while supporting heavy eccentric load should have the high fatigue strength as well as the extremely low structural deflection and vibration in order to maintain the positioning accuracy. The lift column driven by a induction motor is generally in a three-step sliding boom structure and exhibits the time-varying stress distribution according to the up-and-down motion. This study is concerned with the numerical prediction of the fatigue strength of the lift column subject to the time-varying stress caused by the up-and-down motion. The stress variation during a motion cycle is obtained by finite element analysis and the fatigue life is predicted making use of Palmgren-miner's rule and S-N curves. In order to secure the numerical analysis reliability, a 3-D FEM, model in which the detailed lift column structure and the fitting parts are fully considered, is generated and the interfaces between lift column and pads are treated by the contact condition.

• The Inventors News
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• no.53
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• pp.1-16
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• 2006

'여성기업지원에 관한 법률' 개정 한 목소리/발행인 칼럼/'제4회 여성발명경진대회' 수준 높아졌다/심사착수 예정시기 직접 통지 서비스 실시/특허청.한국기계연구원, 업무협약체결/낙도어린이들에게 꿈과 희망 심어주는 초청 행사 가져/특허청 팀장 선발 방식 변화 통한 팀제 강화/디자인 권리화 지원사업 실시한다/'DMB 특허품과 지재권전략 세미나'/'2006 독일 국제발명품 전시회' 회원 4명 수상/고성능 하이브리드 보호복, 출원 증가/'이달의 기능 한국인' 박순복 씨 선정/모방상표, 더 이상 등록 받을 수 없다/국내제약업계, 유사브랜드 너무많아/'2006 여성 재활용 발명경진대회' 개최/순수 한방재료로 만든 헤어 클리닉 화제/발명자에게 편리한 특허제도 마련/차로 마시는 '허브 추출물'로 살충제 만들어/종이컵에도 웰빙 바람이 불고 있다/특허공보 통해 '나의 발명' 확인가능/지역특산품도 지리적 표시로 보호 받는다/한미약품,'비만치료제 특허권 분재' 연승/국내특허, 해외에서 신속하게 심사 처리/'스판덱스 특허소송'에서 일본업체 패소/아모레, 다국적 화장품회사 로레알에 승소/제7차 한국.유럽 특허청장 회담 개최/고부가가치 창출하는 단백질 의약품 개발 필요/한방 진료에도 변화의 새바람 분다/에너지 절감'기능성 유리' 출원 급증/역사 속의 발명품/하루 10분 발명교실/특허Q&A/세상을 밝히는 여성들의 발명 아이디어/'특허넷' 정부기관 최초 CMMI 레벨4인증 획득/'해외지재권 보호 가이드북' 제작배포하다/아이디어 착상 및 발명 기법/고정관념을 깨트려 블루오션을 장악하라/에반스의 증기제분기/50년 후엔 동물과도 대화할 수 있다/첩보용 도구 전달 '발명팀' 실제 존재/중소기업 위한'2006 특허유통 페스티벌' 개최/출원료.심사청구료 반환제도 도입, 시행/'지재권 e-러닝 콘텐츠' 전 세계특허청 교육 자료로 활용/대한변리사회, 미 특허법 세미나 개최/한국여성발명협회 회원사 발명품 가이드

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.9
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• pp.862-868
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• 2010

Development of a small scale aircraft has been carried out for the BASA(Bilateral Aviation Safety Agreement) program in Korea. This aircraft adopted all the composite structures for environmental friendly by low fuel consumption due to its lightness behavior. However the composite structure has s disadvantage which is very weak against impact due to foreign object damages. Therefore the aim of this study is focusing on the damage evaluation and repair techniques of the aircraft composite structure. The damages of composite laminates including the carbon/epoxy UD laminate and the carbon/epoxy fabric face sheets-honeycomb core sandwich laminate were simulated by a drop weight type impact test equipment and the damaged specimen were repaired using the external patch repair method after removing damaged area. The compressive strength test and analysis results after repairing the impact damaged specimens were compared with the compressive strength test and analysis results of undamaged specimens and impact damaged specimens. Finally, the strength recovery capability by repairing were investigated.

• Annual Conference of KIPS
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• 2001.10b
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• pp.1589-1592
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• 2001

일반적으로 아웃소싱은 비용절감이나, 경쟁력 확보를 목적으로 기업 외부에서 필요한 자원, 기술력 및 해결방안 등을 찾는 경영기법으로, 단순용역업무에서부터 기업의 핵심기능인 IT 분야에 이르기까지 폭 넓게 활용되고 있다. 특히 IT 아웃소싱은 일상적인 정보시스템의 운영 및 개선, 네트워크 운영 및 어플리케이션의 유지/개선 등을 외부의 전문가에게 맡겨 점진적인 서비스 수준의 향상과 비용의 절감을 유도하고, 내부자원은 핵심역량에 집중시켜, 기업의 경쟁력을 높이는 하나의 경영수단으로 각광 받고 있다. 본 논문에서는 실제 통신서비스업체의 IT분야를 아웃소싱한 사례 연구를 통해서 IT 아웃소싱의 추진 시 필요한 제반사항과 절차, 추진배경등을 알아보고, 아웃소싱 성과를 결정하는 중요 요소인 서비스 성과측정 모델에 대해 연구하였다. '90 년대 후반 통신시장개방, 본격적인 경쟁체제 돌입등 핵심역량강화 차원에서 시작된 아웃소싱은 통신업체 국내최초의 사례로 처음부터 예상치못했던 어려움과 추진과정에서의 시행착오도 많이 겪었다. 또한, 선진외국사례의 아웃소싱 계약사례 및 서비스수준을 평가하기위한 서비스 수준 약정서등 국내 통신업체 환경에 맞게 잘 짤여지도록 수많은 검토와 사례 연구를 통해 계약을 체결할 수 있었으며, 아웃소싱이후 예상되었던 많은 문제점들을 해결하기위해 아웃소싱 인력들의 의욕수준을 높이기위한 직무 재교육, Incentive 제도 도입, 서비스와 관련된 제반 프로세스 재정립 등을 통하여 소기의 성과를 이룩할 수 있었다. 특히, 통신업체 IT 아웃소싱의 성공요인은 계약적 구조적 측면에 해당하는 적정한 서비스의 평가와 이에 상응하는 대가의 지급방안에 대한 것이고 양 사가 만족할 만한 성과를 내가 위해서는 수직적관계가 아니라 제휴관계로서의 Relationship 을 유지할 수 있도록 이 두가지 모두를 고려 해야만 성공적인 아웃소싱 추진에 한걸음 더 나아갈 것이며, 아울러 향후에도 아직 미흡한 분야인 IT 아웃소싱에서 적정수준의 대가지급 방안 및 바람직한 Relationship 에 영향을 미치는 여러 가지 요인에 대해서도 살펴 봄으로써 IT분야의 Outsourcing을 검토하거나, 추진할 때 도움이 될 수 있도록 하고자 한다.

• Journal of KIISE:Databases
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• v.30 no.2
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• pp.209-224
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• 2003

Recent development of electronic commerce enables the use of Electronic Stock Trading Systems(ESTS) to be expanded. In ESTS, information with various sensitivity levels is shared by multiple users with mutually different clearance levels. Therefore, it is necessary to use Multilevel Secure Database Management Systems(MLS/DBMSs) in controlling concurrent execution among multiple transactions. In ESTS, not only analytical OLAP transactions, but also mission critical OLTP transactions are executed concurrently, which causes it difficult to adapt traditional secure transaction management schemes to ESTS environments. In this paper, we propose Secure One Snapshot(SOS) protocol that is devised for Secure Transaction Management in ESTS. By maintaining additional one snapshot as well as working database SOS blocks covert-channel efficiently, enables various real-time transaction management schemes to be adapted with ease, and reduces the length of waiting queue being managed to maintain freshness of data by utilizing the characteristics of less strict correctness criteria. In this paper, we introduce the process of SOS protocol with some examples, and then analyze correctness of devised protocol.

• Composites Research
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• v.31 no.1
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• pp.17-22
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• 2018

Long Fiber Prepreg Sheet (LFPS) has the advantages of excellent production efficiency and formability for complex shapes compared to conventional continuous fiber reinforced composites. When fibrous composites are used with different materials, joining method is important because strength of the joining part determines the strength of the hybrid structure. In this study, the adhesive joint strengths of co-cured LFPS and aluminum were evaluated under various surface treatment conditions and environmental conditions (temperature and moisture conditions). Mechanical abrasion and plasma exposure were used for the surface treatment. The adhesive joints experienced various surface treatments were tested by using single lap joint specimens. Adhesive strengths under various conditions were compared and the most appropriate condition was determined.

• Journal of Sensor Science and Technology
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• v.11 no.3
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• pp.125-131
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• 2002

Respiratory air flow rate is necessarily measured for the pulmonary function evaluation. The currently used devices are exposed to the problems of measurement reliability and cross-patient infection. The present study introduced a new technique which converted the bidirectional air flow rate into averaged dynamic pressure based on the famous Bernoulli's energy conservation principle. Single use plastic sensing element was assembled within the flow tube(mouth piece) made of paper, which was named "functional single use flow tube". Experiment demonstrated only ${\pm}1.5%$ relative error in the standard 3L volume measurement procedure well within the error limit suggested by the American Thoracic Society(ATS). Disposable use design completely eliminated cross-patient infection. The present device is best useful and safe for clinical respiratory air flow measurement such as spirometry.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.4
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• pp.86-93
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• 2010

The wear of railway track affects loss of rough ride, noise or vibration of train and traveling safety. Moreover as the track is worn away, this promotes destruction of structural mechanism of rail track which can bring about increasing of rail track maintenance cost drastically. For this reason, it is very important and interested research subject to design railway track structure and to analyse train movement mechanism based on systematic analysis of the reasons causing rail wear possible in real field. In this research, for the efficient maintenance, Life Cycle Performance of rail track and maintenance characteristics are computed considering some track components such as track type, contracting type, sleeper type and roadbed type. Time - Wear probabilistic distribution relationship as well as multiple regression analysis based on time, curvature and wear data are computed to predict the service life remainder of railway track and to be adapted to safety assessment.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.471-478
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• 2000

For many decades, the railway was constructed using tracks with jointed rails of relatively short lengths. The joints cause many drawbacks in the track and lead to signeficant maintenance cost. so, railroad engineers became interested in eliminating joints. Continuous welded rail(CWR) track has many advantages over the conventional jointed-rail track. but, in the case of the elimination of rail joints, it may cause the track to be suddenly buckled laterally by thermal loads. In this paper, firstly, 3-D CWR track model and CWRB program exactly considering the influence of tie are developed far linear static and buckling analysis using finite element method. Characteristics of CWR track model are using 7-dofs beam element as rail, Offset technic exactly considering centroid axies difference of track components(rail, rail-pad-fastener, tie), and Thermal gradient considering thermal difference of top flange and bottom flange in rail section.. second,, Through the static and linear buckling analysis by CWRB, Influences of various track components (rail, ballast, fastener, tie and so on..) on CWR track behavior and stability was characterized.