• 제목/요약/키워드: Center of effort

검색결과 812건 처리시간 0.026초

고속전철의 Wheel Slip Protection에 관한 연구 (A Study on the Wheel Slip Protection for Korean High-Speed Railway Train)

  • 김문섭;황돈하;김종수;류홍제;전정우;김용주
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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    • pp.420-422
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    • 1999
  • To improve traction effort performance and stability of Korean High-Speed Railway Train, a practical re-adhesion controller including a novel wheel slip protection control scheme is proposed. The presented method is verified by various train running simulations by induction motor vector control with PWM inverter.

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The Factorial Structure and Psychometric Properties of the Persian Effort-Reward Imbalance Questionnaire

  • Babamiri, Mohammad;Siegrist, Johannes;Zemestani, Mehdi
    • Safety and Health at Work
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    • 제9권3호
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    • pp.334-338
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    • 2018
  • Background: With global changes in the current state of work and employment, the role of health-adverse psychosocial work environments has received increasing attention in developed as well as in rapidly developing countries. Thus, there is a need to apply valid measurement tools for monitoring and preventive purposes. This study aims to examine the factorial structure and psychometric properties of the Persian version of the effort-reward imbalance (ERI) questionnaire, assessing one of the internationally leading concepts of stressful work. Methods: This descriptive cross-sectional study of a random sample of 202 white collar employees in an industrial company in Iran analyzes the ERI scales by exploratory and confirmatory factor analysis. Moreover, aspects of construct and criterion validity are tested. To this end, correlations of ERI scales with subscales of organizational injustice, a complementary work stress model, and also the correlations of ERI scales with a questionnaire assessing psychosomatic symptoms are performed. Results: Internal consistency of the three ERI scales was satisfactoryy (Cronbach ${\alpha}$ effort: 0.76, reward: 0.79, overcommitment: 0.75). Fit indices of confirmatory factor analsis pointed to an adequate representation of the theoretical construct (e.g., adjusted goodness of fit index (AGFI): 0.73, goodness of fit index (GFI): 0.78). Negative correlations with subscales of organizational injustice supported the notion of construct validity of the ERI scales, and positive correlations of ERI scales with psychosomatic symptoms indicated preliminary criterion validity. Conclusion: The Persian version of the ERI questionnaire has acceptable psychometric properties and can be used as a valid instrument in research on this topic.

Push-Pull Type 철도차량 Jerking 현상 해석 (Dynamic Analysis of Jerking in Push-Pull Type Train)

  • 김영준;박상규
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 1998년도 창립기념 춘계학술대회 논문집
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    • pp.502-509
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    • 1998
  • The scheme to reduce jerking phenomena in one push-pull type trainset was proposed. To simulate the jerking between coaches, dynamic analysis model was made. This model could analyze longitudinal dynamic behavior between locomotives and coaches caused by spring and damping characteristics of couplers and center pivots; characteristic curves of traction and braking. To validate the analysis results, tests were conducted in the same driving and braking condition. Comparison of longitudinal acceleration between simulation and test results shows a good agreement. To minimize the jerking phenomena, lots of dynamic simulations were conducted with varying driving/braking effort curve. From the results of simulations, an efficient and economic way to reduce jerking phenomena was found to be to reduce slope of tractive effort curve and synchronize braking time between locomotives and coaches. Test results show that this way could reduce the jerking Phenomena. To express jerkins Phenomena quantitatively, maximum peak to peak values of acceleration were used.

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A Study on Sales depending upon Meat Consumption Class: Focused on Hanwoo meat 1++A Class Consumption Class

  • Yun, Sun-Ja;Kim, Gi-Pyeong
    • 융합경영연구
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    • 제2권2호
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    • pp.10-14
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    • 2014
  • The study investigated consumption patterns and inclination of consumers of Hanwoo meat being more expensive than imported meat and/or beef cattle meat based on the author's business experience at the shop in Budang Seongnam. The author who has managed shop firstly investigated customers' inclination and/or propensity. The author heard specific customer's story at neighboring shopping center, and each customer's buying method, occupation, financial power and apartment size and others, and forecast visiting customer's buying and demand upon part of the beef that customer asks for. The aut hor who sold out limited scope of beef product at limited area thought that he did narrow scope of business. The author would make effort to sell product enough to meet customer's taste by better quality product from point of view of customers. The author would make effort to supply good quality beef products to the customers who relied upon the author's butcher's.

Isolation of Sorangium cellulosum Carrying Epothilone Gene Clusters

  • Hyun, Hye-Sook;Chung, Jin-Woo;Kim, Ji-Hoon;Lee, Jong-Suk;Kwon, Byoung-Mog;Son, Kwang-Hee;Cho, Kyung-Yun
    • Journal of Microbiology and Biotechnology
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    • 제18권8호
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    • pp.1416-1422
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    • 2008
  • Epothilone and its analogs are a potent new class of anticancer compounds produced by myxobacteria. Thus, in an effort to identify new myxobacterial strains producing epothilone and its analogs, cellulose-degrading myxobacteria were isolated from Korean soils, and 13 strains carrying epothilone biosynthetic gene homologs were screened using a polymerase chain reaction. A migration assay revealed that Sorangium cellulosum KYC3013, 3016, 3017, and 3018 all produced microtubule-stabilizing compounds, and an LC-MS/MS analysis showed that S. cellulosum KYC3013 synthesized epothilone A.

Coating defects in polymer-coated drug-eluting stents

  • Bedair, Tarek M.;Cho, Youngjin;Park, Bang Ju;Joung, Yoon Ki;Han, Dong Keun
    • Biomaterials and Biomechanics in Bioengineering
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    • 제1권3호
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    • pp.131-150
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    • 2014
  • Vascular stenting has a great attention as a treatment for coronary arteries diseases as compared with percutaneous balloon angioplasty. In-stent restenosis and thrombosis are side effects resulting from using bare metal stent (BMS). Employing platelet therapy allowed to reduce the rate of thrombosis, however, the rate of restenosis remains a major problem. In 2002, drug-eluting stents (DESs) were introduced as an effort to reduce the restenosis. The commercially available DESs continue to suffer from coating defects that might lead to a series of adverse effects. Most importantly, multiple concerns remain regarding the polymer coating integrity on metal surfaces or the relation of polymer irregularities to longterm adverse events.

디지털정보서비스를 통한 전문정보센터의 이용자중심 정보서비스 구현에 관한 연구 (A Study on User-centered Information Service Applying Digital Information Service in Special Information Center)

  • 최희윤
    • 정보관리연구
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    • 제29권1호
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    • pp.54-73
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    • 1998
  • 사회의 전반적인 정보화와 정보환경의 디지털화에 따라 전문정보센터의 역할도 변화되어야 한다. 효율적인 정보서비스를 수행하기 위해서는 기존의 정보서비스 체제나 시스템으로부터 발전적인 변화가 필요하다. 본고에서는 다양한 디지털매체와 국내외 통신망의 결합을 통해 부가가치가 높은 서비스를 창출할 수 있는 디지털정보서비스에 대한 이론적인 근거와 구체적인 실천사례를 통해 전문정보센터에서의 이용자중심 정보서비스의 효율적 구현방안을 제시하고자 한다.

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History of Minimally Invasive Surgery for Gastric Cancer in Korea

  • Kim, Young-Woo;Yoon, Hong-Man;Eom, Bang-Wool;Park, Ji-Yeon
    • Journal of Gastric Cancer
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    • 제12권1호
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    • pp.13-17
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    • 2012
  • Laparoscopic gastrectomy was begun in 1995 in Korea. But, there was 4 years gap to reactivate in 1999. High incidence of gastric cancer and increasing proportion of early cancer through national screening program along with huge effort and enthusiasm of laparoscopic gastric surgeon, and active academic exchange with Japanese doctors contributed development of laparoscopic gastrectomy in Korea. Study group activity of Korean Laparoscopic Gastrointestinal Surgery Study (KLASS) group and Collaborative Action for Gastric Cancer (COACT) group were paramount to evoke large scale multicenter clinical study and various well performed clinical studies. This review encompasses mainly international publications about this area so far in Korea.

고객접점센터 구축 요소와 도입 효과의 관계에 관한 연구 (A Study on the Relationship between Customer Interaction Center′s Design Elements and Its Effectiveness)

  • 김성근;김은정
    • Journal of Information Technology Applications and Management
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    • 제10권3호
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    • pp.143-162
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    • 2003
  • Today's firm runs on a customer-centric environment. Customers prefer to deal with companies that are accessible at anytime, from anywhere, in any form. Thix trend requires an ever-increasing number of channels to interact with the firm. And these channels ought to be integrated as well. To meet these challenges firms tend to rely on a customer interaction center (CIC) solution, enabling two-way interactions with customers through seamless contact channels. Though many firms these days tend to introduce the CIC into their organization, there is not much empirical research dealing with design elements that have to be fabricated in the CIC. This study is to investigate the relationship between CIC design elements and CIC effectiveness. To meet this objective we have contacted and surveyed a number of firms that are operating some form of CIC. We also describe a few success and failure cases in an effort to deliver issues or insights that should be considered in introducing CIC.

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자속측정에 의한 동기발전기의 운전중 진동 감시기법 (On-Line Vibration Monitoring Techniques for Synchronous Generators by Flux Measurement)

  • 김지현;황돈하;장기찬;김용주;권영안;송상옥
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 하계학술대회 논문집 B
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    • pp.952-954
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    • 2002
  • The effort for measuring the rotor vibration caused by the short of rotor winding or air-gap eccentricity has been carried on. This paper introduces on-line vibration monitoring technologies using search coils to measure flux for synchronous generators. A 3,300/6,600 (V), 150 [kW] synchronous generator is built, and search coils are designed and inserted in the wedges. Furthermore, air-gap eccentricity is analyzed by finite element method and compared with experiment tests. Induced voltages caused by different air-gap eccentricity on the search coils are compared as well.

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