• 제목/요약/키워드: critical gap

검색결과 457건 처리시간 0.024초

마찰재 그루브에 따른 습식 클러치 드래그 토크 변화 연구 (Effect of Angle and Density of Grooves between Friction Plate Segments on Drag Torque in Wet Clutch of Automatic Transmission)

  • 류진석;성인하
    • Tribology and Lubricants
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    • 제30권2호
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    • pp.71-76
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    • 2014
  • As the importance of transmission efficiency to reducing fuel consumption and conserving the environment rapidly increases, reducing the drag torque in an automotive wet clutch is emerging as an important issue in the automotive industry. The drag torque in a clutch occurs from viscous drag generated by automatic transmission fluid in the narrow gap between separate friction plates. In this study, the drag torques in an automotive wet clutch are investigated with respect to the angle and density of the grooves between separate friction plates by three-dimensional finite element simulation of a single set of wet clutch disks considering the two-phase flow of air and oil. The simulation results shows that the drag torque generally increases with the rotational speed to a critical point and then decreases at the high-speed regime. The grooves between the plates plays an important role in reducing the drag peak, and the inclined angle of the grooves affects the oil flow. The grooves with an angle of $50^{\circ}$ shows the lowest drag torques at both low and high speeds. The flow vectors inside the $50^{\circ}$ grooves shows clear evidence that the fluid flows out more easily from the grooves compared with the flow vectors inside grooves with lower angles. The simulation results shows that increasing the number of grooves (density of grooves) decreases the drag torque.

그림그리기 전략을 통한 초.중등수학의 연립방정식 지도 연결성 강화 (Crossing the Gap between Elementary School Mathematics and Secondary School Mathematics: The Case of Systems of Linear Equations)

  • 권석일;임재훈
    • 대한수학교육학회지:수학교육학연구
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    • 제17권2호
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    • pp.91-109
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    • 2007
  • 이 논문은 이원일차연립방정식과 관련하여 초등수학과 중등수학의 연결성 문제를 분석한 것이다. 초등학교 수학 교과서와 중학교 수학 교과서에서 이원일차연립방정식 문장제가 다루어지는 방식을 연결성 측면에서 분석하고, 연결성을 강화하는 접근법을 제안하였다. 교과서 분석 결과 이원일차연립방정식 문장제에 대한 초등학교 수학 교과서와 중학교 수학 교과서의 접근법이 서로 연결되어 있지 않았다. 이에 이 논문에서는 이원일차연립방정식 문장제 해결에 그림그리기 전략을 도입하여 초등수학과 중등수학의 연결성을 강화하는 방안을 한 초등 6학년 아동의 사례를 통해 제시하였다.

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건강보험 보장성 확대정책의 집행분석: Winter의 정책집행모형의 적용 (An Implementation Analysis of the National Health Insurance Coverage Expansion Policy in Korea: Application of the Winter Implementation Model)

  • 유수연;강민아;권순만
    • 보건행정학회지
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    • 제24권3호
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    • pp.205-218
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    • 2014
  • Background: Most studies on the national health insurance benefit expansion policy have focused on policy tools or decision-making process. Hence there was not enough understanding on how policies are actually implemented within the specific policy context in Korea which has a national mandatory health insurance system with a dominant proportion of private providers. The main objectives of this study is to understand the implementation process of the benefit coverage expansion policy. Unlike other implementation studies, we tried to examine both the process of implementation and decision making and how they interact with each other. Methods: Interviews were conducted with the ex-members of the Health Insurance Policy Review Committee. Medical doctors who implement the policy at the 'street-level' were also interviewed. To figure out major variables and the degree of their influences, the data were analyzed with Winter's Policy Implementation Model which integrates the decision making and implementation phases. Results: As predicted by the Winter model, problems in the decision making phase, such as conflicts among the members of committee, lack of applicable causal theories application of highly symbolic activities, and limited attention of citizen to the issue are key variables that cause the 'implementation failure.' In the implementation phase, hospitals' own financial interests and practitioners' dependence on the hospitals' guidance were barriers to meeting the policy goals of providing a better coverage for patients. Patients, the target group, tend to prefer physicians who prescribe more treatment and medicine. To note, 'fixers' who can link and fill the gap between the decision-makers and implementers were not present. Conclusion: For achieving the policy goal of providing a better and more coverage to patients, the critical roles of medical providers as street-level implementers should be noted. Also decision making process of benefit package expansion policy should incorporate its influence on the implementation phase.

지역 의료불평등 해소를 위한 미충족 의료지표 활용의 비판적 분석 (Critical Analysis of Unmet Healthcare Needs Index for Addressing Regional Healthcare Inequality)

  • 박유경;김진환;김선;김창엽;한주성;김새롬
    • 보건행정학회지
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    • 제30권1호
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    • pp.37-49
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    • 2020
  • Background: Unmet healthcare needs have many advantages for measuring inequalities in healthcare use. However, the existing indicator is difficult to capture the reality of unmet healthcare needs sufficiently and is not quite appropriate in comparing regional inequality. The purpose of this study is to critically analyze the utilization of the unmet healthcare need indicator for regional healthcare inequalities research. Methods: We used the level of healthcare accessibility and healthcare need to categorize the regions that are known to cause differences in healthcare utilization between regions and verified how existing unmet healthcare need indicator is distributed at the regional level. Results: Four types of regions were classified according to the high and low levels of healthcare needs and accessibility. The hypothesis about the regional type expected to have the highest unmet healthcare need was not proved. The hypothesis about the lowest expected regional type was proved, but the difference in the average rate of unmet healthcare needs among regional types was not significant. The standard deviation of the rate of unmet healthcare needs among regions within the same type was also higher than the overall regional variation, which also disproved the whole frame of hypothesis. Conclusion: Failure to prove the hypothesis means the gap between the supposed meaning of the indicator and the reality. In order to understand the current state of healthcare utilization of people in various regions of Korea and to resolve inequality, fundamental research on the in-depth structure and mechanisms of healthcare utilization is needed.

바이오 클러스터에서의 트리플 힐릭스 관계 연구: 싱가포르 사례를 중심으로 (Triple Helix of University-Industry-Government Relations in Biotechnology Cluster: the Case of Singapore)

  • 남재걸
    • 한국경제지리학회지
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    • 제17권4호
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    • pp.801-816
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    • 2014
  • 본 연구는 트리플 힐릭스 모형을 활용하여 싱가포르의 첨단생명과학단지에 대한 분석을 시도하였다. 트리플 힐릭스 모형의 이론적 논의와 현실에서의 산 학 관 관계의 차이점에 주목하고 연구문제를 제시하였다. 싱가포르 첨단 생명과학단지는 대학, 정부 그리고 기업체간의 삼자간 상호작용이 존재하고 있었지만, 트리플 힐릭스 모형의 이론적 틀과는 다르게 작동하고 있었다. 우선, 대학보다는 정부가 삼자간의 관계를 결정할 정도의 주도적인 역할을 하고 있었다. 정부는 이민정책, 장학금, 세금감면 및 세금이외의 인센티브 정책 등 생명과학 및 의료산업에 대한 포괄적인 지원 정책을 추진하였다. 또한 정부는 초기단계에서부터 삼자간 관계를 주도하였으며 이러한 역할은 클러스터가 어느 정도 진전된 이후에도 지속되고 있었다. 정부의 이러한 지원은 삼자간 상호작용을 가능하게 하는 추동력으로 작동하고 있었다.

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Financing the Commercialisation of Green Innovation

  • Park, Jeongwon;Jeong, Changhyun
    • STI Policy Review
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    • 제4권1호
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    • pp.94-118
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    • 2013
  • Innovation plays a large role in green growth. While it is a widely accepted view that, without innovation, it would be very difficult and costly to address major environmental issues, innovation itself tends to be constrained by limited access to eco-financing and is inherently risky, often requiring a long-term horizon. Although global consensus is more or less established as to the urgency and necessity of accelerating green innovation, the quality and quantity of financing in this area is largely insufficient, with increasing funding gaps in many countries. A new financial mechanism is urgently needed in order to re-orient financial flow and enable innovators to overcome the valleys of death that occur throughout the innovation cycle. A number of different modalities exist in financing the commercialisation of eco-innovation. Existing mechanisms have not been as successful as expected, revealing critical limits to furthering certain types of projects that are essential for economic and environmental progress. Experts' estimations have shown that the funding gap will widen in the coming years as demand for clean energy and green infrastructure rises, and as green technologies and innovation develop faster than the market for it can develop. Against this backdrop, the main purpose of this research is threefold: to identify issues and problems regarding current means of funding for eco-innovation and green projects; to provide insight into securing longterm green financing by looking at European cases; and ultimately to suggest policy implications for designing and implementing eco-specific financial instruments, focusing on governments' roles in sustainable financing for eco-innovation. This study analyses different models of financing mechanisms, a mix of public and private funds, in view of suggesting conditions for the sustainable financing of green projects, especially for large-scale high-risk projects. Based on the findings from the analyses of mechanisms and the shortcomings of the existing funding modalities, this study ultimately suggests policy implications for effectively supporting the commercialisation of eco-innovation.

경쟁전략요소에 대한 CM기업의 인식에 관한 연구 (A Study on Elements of CM Firms' Competitive Strategy)

  • 백승룡;김한수
    • 한국건설관리학회논문집
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    • 제14권5호
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    • pp.122-130
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    • 2013
  • CM시장에서의 경쟁이 심화되고 있는 상황에서 CM기업이 경쟁우위를 점하는 것은 매우 중요한 기업 현안이다. 이를 위해서는 적합한 경쟁전략을 갖추어야 하고 이를 통해 지속적으로 경쟁우위를 확보할 필요가 있다. 본 연구의 목적은 CM시장에서 경쟁우위를 점하기 위해 CM기업들이 중요하게 여기는 경쟁전략요소를 분석하고 이들 경쟁전략요소에서 나타나는 주요 특징과 시사점을 도출하는데 있으며 마이클 포터(Michael Porter)의 경쟁전략모델을 분석방법론으로 활용하였다. 연구 결과, 상위그룹에서는 차별화전략을 중요시 여기는 반면, 하위그룹에서는 집중화전략을 중요시 여기는 것으로 나타났다. 그러나 원가우위전략은 상하위 그룹에서 동일하게 상대적으로 중요도가 낮은 경쟁전략으로 인식되고 있는 것으로 나타났다. 비록 상하위 그룹에 따라 각 경쟁전략요소의 세부적인 순위에는 차이가 있었지만 종합적으로 보면 특화된 CM서비스 제공이 중요한 경쟁전략요소로 인식되고 있었다. CM기업의 경쟁전략요소에 대한 이해는 현재 CM기업들이 중요하게 생각하는 경쟁전략의 방향성과 내용을 파악할 수 있게 하며 향후 자사(自社)의 경쟁전략 수립을 위해 유용하게 활용될 수 있다.

$SF_6$ GIS용 스페이서 표면에서의 파티클에 의한 절연파괴 특성연구 (A Study of Particle-Initiated Breakdown Characteristics on a Spacer Surface for $SF_6$ GIS)

  • 김재호;이용길;김동의;이세훈;김정달
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1994년도 하계학술대회 논문집 C
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    • pp.1536-1539
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    • 1994
  • The influence due to metallic particle contaminated on spacer surface is remarkable in the decreasing of dielectric strength in $SF_6$ GIS. In relation with this problem, We studied, AC flash-over voltage characteristics and breakdown mechanism are investigated under metallic particle initiated condition in $SF_6$ gas by varying the particle position, particle shape with a plane-plane electrode. The main results arc as follows 1. The small amount of the metallic particle in the gap do not make flash-over voltage to be influence, but the significant decrease of th flash-overed voltage is result in case of the big and long size of the metallic paraticle. 2. Influence of the flash-over voltage are lowest in the mid and are highest in the electrode of metallic particle position. 3. In case of the initiated metallie particle, The more the pressure are high, the more the recluced ratio of flash-over voltage are high. 4. The metallic particle shape which results in the reduced flash-over voltage forced the critical pressure to move in to the region of low pressure. 5. The existance of the metallic particle on the upper electrode side and high pressure make the decreasing ratio of flash-over voltage bigger than that of the ground side electrode.

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사이버 러닝 환경에서 개별화 학습을 위한 학습자 인지구조 기반 ITS 교수·학습 모형과 시스템에 관한 연구 (Study on ITS Teaching-learning Model and System Based on Learner's Cognition Structure for Individualized Learning in Cyber Learning Environment)

  • 김용범;정복문;최지만;백장현;김태영;김영식
    • 컴퓨터교육학회논문지
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    • 제10권6호
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    • pp.79-89
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    • 2007
  • 지식정보 사회의 도래는 새로운 교육 패러다임에 적합한 교수-학습 과정을 지원하기 위해 다양한 형태의 e-러닝의 모형과 시스템을 요구하며, 이에 따라 인터넷과 지능형 교육 시스템(ITS; intelligent tutoring system)을 적용한 e-러닝 환경의 교수-학습 시스템에 대한 연구가 지속적으로 진행되어 왔다. 그러나 현재 운영되고 있는 교육 현장의 인프라와 u-러닝의 개념 사이에는 상당한 격차가 존재한다. 이에 따라 본 연구에서는 현재 구축된 교육 현장의 인프라에서 u-러닝의 개념을 적용할 수 있는 학습자의 인지구조에 기반한 ITS 교수-학습 모형과 시스템을 개발하고, 타당성을 검증하였다. 또한 본 연구에서 제안하는 지식표현기법을 통해 개별화 학습이 효과적으로 적용될 수 있도록 학습자 인지구조를 표현하였다.

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AHP를 활용한 프로젝트 팀 구성원의 개인역량 상대적 중요도 연구 (A Study on Relative Importance of Project team members Competencies Using AHP)

  • 김영대;이진아;오민정
    • 산업경영시스템학회지
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    • 제43권3호
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    • pp.216-227
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    • 2020
  • The purpose of this paper is to identify a relative importance and priority of the factors of Competencies of project team member. It aims to present the differential competency factors from a differentiated perspective by applying the Leadership Development Questionnaire, which is the competency dimension required for manager, to team member. (1) Background: The diverse needs of customers and companies, and the uncertainty, complexity, ambiguity, and volatility of the environment surrounding the company in the era of the Fourth Industrial Revolution threaten the survival of company. In this respect, companies should implement the project management approach and strive to increase the capabilities of each team member. (2) Methods: AHP method was used to prioritize which factors were considered more importance level and the gap of relative importance level between project manager group and team members group. (3) Results: In the analysis of the relative importance of the upper class, weights were derived in the order of managerial competence, intellectual competence, and emotional competence. The sub-factor that respondents prioritize was communication as the 1st priority, and it was analyzed in the order of strategic perspective, achieving, critical analysis and judgement, and vision and imagination. There were some differences in the ranking of the relative importance of achieving and vision and imagination attributes between the PM group and TM group, it was analyzed that there was no significant difference overall. (4) Implications: The results of this study confirmed the recognition that team members are required to have the same competencies as the project manager. And based on the priorities of the competencies required of team members, companies are expected to cultivate professional and competent team members, and expand the roles and authority of team members so that they can actively carry out projects.