• Title/Summary/Keyword: Leading

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Effect of the Blade Leading Edge on the Performance of a Centrifugal Compressor

  • Chu, Leizhe;Du, Jianyi;Zhao, Xiaolu;Xu, Jianzhong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.03a
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    • pp.168-172
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    • 2008
  • Three different geometry shapes of the blade leading edge in a centrifugal compressor were investigated in this paper. Numerical simulation was done to analyze the effect of the leading edge shape on the performance of the centrifugal compressor. The result shows that compared to the blunt leading edge, the circular leading edge will raise the chocking mass flow. The pressure ratio and efficiency will increase obviously. Using elliptical leading edge will get a further improvement on the performance than circular leading edge. The analysis of the flow field shows that the leading edge often causes flow separation near the inlet; using circular leading edge and elliptical leading edge will reduce the separation. What's more, using circular and elliptical leading edge will also reduce the wake loss near the outlet of the impeller. In a centrifugal compressor, using circular or elliptical leading edge on the splitter will improve the pressure loading distribution of main blade near the position of the splitter leading, which will increase the pressure ratio.

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A Study on the National Leading ADR and Private Leading ADR (국가주도형 ADR과 민간주도형 ADR에 관한 연구)

  • Choi, Seok-Beom
    • Journal of Arbitration Studies
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    • v.20 no.3
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    • pp.71-91
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    • 2010
  • ADR is alternative dispute resolution that includes mediation, adjudication, arbitration, conciliation and ombudsman schemes. ADR may be an alternative to going to court or to a tribunal. The main types of ADR are conciliation, arbitration or mediation and ADR is divided into national leading ADR and private lading ADR and national leading ADR includes court-annexed ADR and administrative ADR. Court-annexed ADR has become a well established feature of the judicial systems on a global basis. The bulk of court-annexed ADR in Glove is by way of mediation. Thus each nation takes part in ADR by court involvement and Enactment of ADR-related Laws. And the involvement of nations have both the regulative character and promotive character in ADR. In addition to the national leading ADR, the private leading ADR also must be activated as United Kingdom. Thus this paper deals with national leading ADR and private leading ADR and the purpose of this paper is to contribute to the activation of ADR by studying the promotion and limited the involvement of nation in ADR and private leading ADR in United Kingdom.

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A Study on the Effective Maintenance Method of the Stair Passage Leading Light installed In the Shopping Building (상가건물 계단통로유도등의 유지관리 효율화 방안에 관한 연구)

  • Lee, Young-Sam
    • Journal of the Korea Safety Management & Science
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    • v.18 no.1
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    • pp.1-8
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    • 2016
  • This study was conducted by survey and inspection of stair passage leading lights in shopping buildings which are more than 5 stories and have an underground parking lot located at Pyeongtaek-si and Seongnam-si. Number of shopping building for this study is 30 and of stair passage leading light inspected by two lights in each shopping building is 60. The result of this study is that the type of installed leading lights is LED(77%), and 60% of leading lights has problem such as no cleaning, scratch and discoloration, etc. The height of installed leading lights meets the fire law which is less than 1m from the floor. Visible condition of leading lights is good except some leading lights which have a little visible problem due to banner advertisement. 37% of standby power has flickered and went out. 93% of total leading lights meets the fire law which is more than 1lux from 0.5m distance, but cold cathode fluorescent lamps(CCFLs) have the problem which not meets proper brightness level based on fire law. In additional measurement result, zero lux of leading lights is 32%(from 1m distance), 68%(from 1.5m distance) and 98%(from 2m distance). Leading light is very important facility because it is eyes and guide when emergency. Therefore, proper fire facility operating function inspection and total detailed inspection are important to keep the good condition of leading light except simple visual check, and also improvement in law system of type approval, fire construction inspection and illumination level will be needed.

Qualitative Inquiry of Features of Science Education Leading Schools on Students' Positive Experiences about Science (학생들의 과학긍정경험에 영향을 주는 과학교육 선도학교 특성에 대한 질적 탐구)

  • Kwak, Youngsun;Lee, Sunghee;Kang, Hunsik;Shin, Youngjoon;Lee, Soo-Young
    • Journal of Korean Elementary Science Education
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    • v.38 no.3
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    • pp.317-330
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    • 2019
  • The purpose of this study is to investigate the influences of science leading schools on primary and middle school students' positive experiences about science (PES) through in-depth interviews with teachers in charge of science leading schools. Science leading schools at the primary and middle school level such as Creative Convergent Science Labs and Student Participatory Science Classes were investigated and 11 teachers were participated in focus group interviews. Teacher in-depth interviews were conducted to explore the factors that led to the effectiveness of science leading schools in improving the student's PES in light of operational characteristics of science leading schools, characteristic factors of science leading schools on students PES, and improvement plans and requirements of science leading schools, as well as implications for general high schools. Science leading schools including Creative Convergent Science Labs and Student Participatory Science Classes applied for the leading school funding to secure supplies, equipments, and lab improvement for authentic science classes. In addition, reconstructed the curriculum more broadly than before, and emphasized and expanded student participatory classes and process-centered assessment at the teacher learning community level. Through student-participatory classes, the science leading schools stimulate students' interest in science, provide students with PES) through various instructions including projects, engage students in interesting science experiences in Creative Convergent Science Labs, and enhance inquiry skills and PES as well as science content knowledge. Based on the results, ways to spread the characteristics of science leading schools to general schools are suggested including expanding budget support, securing the space of science labs and improving spatial composition, providing diverse teaching and learning materials, diversifying assessment subjects and methods, and the necessity of teachers' continuous professional development, etc.

Proposed Strategy to Enhance Support and Promotion of Leading Farms (우수농업경영체 발굴육성 전략의 발전적 제언)

  • Kim, Sa-Gyun;Choe, Young-Chan
    • Journal of Agricultural Extension & Community Development
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    • v.12 no.2
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    • pp.243-255
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    • 2005
  • The "leading farms" or "superior management farms" were relatively capable to overcome various limitations in rapidly changing agricultural environment and economic conditions, and quick to adopt agricultural management innovations and accomplish more compared to the other farms in shorter durations. The farmers from these "leading farms" were innovative and dynamic, and endowed with potentials to be the core leaders in rural society. Their adaptability created a difference and worthy of emulations. The purpose of this research was to propose a policy to develop, promote and sustain these leading farms. There were some problems in communication structures and in implementing agricultural policies for upbringing leading farmers. In coordination with the Ministry of Agriculture and Forestry(MAF) and Rural Development Administration (RDA), this article attempted to come up with workable strategies to solve these problems affecting the leading farms.

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Control of Delta-Wing Vortex by Micro-Fin-Type Leading-Edge Flap

  • Sohn, Myong-Hwan;Chung, Hyoung-Seog;Cho, Dong-Hyun
    • International Journal of Aeronautical and Space Sciences
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    • v.7 no.2
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    • pp.128-136
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    • 2006
  • The present study examined the effects of micro leading-edge flaps on the vortex characteristic changes of a double-delta wing through pressure measurements of the wing upper surface and PIV measurements of the wing-leeward flow region. The experimental data were collected and analyzed while changing the deflection angle of the leading-edge flaps to investigate the feasibility of using micro leading-edge flaps as flow control devices. The test results revealed that the leading edge modification could greatly alter the vortex flow pattern and the wing surface pressure of the delta wing, which suggested that the leading-edge flaps could be used as an effective device for the control of delta-wing vortex flow.

An Exploratory Study on the Success factors of the Firm Leading Community in the Point of Community Operator (기업주도형 커뮤니티의 성공요인에 관한 탐색적 연구: 커뮤니티 운영자 관점에서)

  • Jun, Byoung-Ho;Kim, Kyung-Mi;Kang, Byung-Goo
    • Knowledge Management Research
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    • v.9 no.2
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    • pp.15-34
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    • 2008
  • The firm leading community that is built to achieve firm's ad hoc purpose has two interested parties, operator and user. The success of the firm leading community, therefore, can be driven by meeting the needs of both parties. Most studies of the community, however, have focused not on operator but on user so far. This study identifies two variables-operating activities and organizational support-as success factors of firm leading community based on prior studies and analyzes them in term of the operator of firm leading community through 2nd in-depth interview. The result of study shows that organizational support affects operating activities and then both operating activities and organizational support affect the success of the firm leading community.

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Aerodynamic Characteristics of Delta Wing According to Leading Edge Geometries (앞전 형상에 따른 삼각 날개의 공력 특성)

  • Jin, Hak-Su;Kim, Sung-Cho;Kim, Jeong-Soo;Choi, Jong-Wook
    • Journal of the Korean Society of Visualization
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    • v.5 no.2
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    • pp.56-63
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    • 2007
  • Flow visualization and aerodynamic characteristics of delta wings with two different leading edge geometries are investigated by PIV system and wind tunnel balance when the Reynolds number is about based on the freestream velocity and the root chord length. Delta wing models have 65-deg swept angle, and the leading edge shapes are divided into round- and sharp- type. The experimental results indicated that the leading-edge vortex strength and aerodynamic coefficient in the round leading edge are stronger and more, respectively than those in the sharp one. Therefore the flow interactions between vortices and the boundary layer are more desirable or more rapidly swirled in the round-type leading edge.

Recognition of a Close Leading Vehicle Using the Contour of the Vehicles Wheels (차량 뒷바퀴 윤곽선을 이용한 근거리 전방차량인식)

  • Park, Kwang-Hyun;Han, Min-Hong
    • Journal of Institute of Control, Robotics and Systems
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    • v.7 no.3
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    • pp.238-245
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    • 2001
  • This paper describes a method for detecting a close leading vehicle using the contour of the vehi-cles rear wheels. The contour of a leading vehicles rear wheels in 속 front road image from a B/W CCD camera mounted on the central front bumper of the vehicle, has vertical components and can be discerned clearly in contrast to the road surface. After extracting positive edges and negative edges using the Sobel op-erator in the raw image, every point that can be recognized as a feature of the contour of the leading vehicle wheel is determined. This process can detect the presence of a close leading vehicle, and it is also possible to calculate the distance to the leading vehicle and the lateral deviation angle. This method might be useful for developing and LSA (Low Speed Automation) system that can relieve drivers stress in the stop-and-go traffic conditions encoun-tered on urban roads.

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Infrastructure and Leading Commodity Identification on Poverty Alleviation in Buru Regency, Indonesia

  • WAHYUNINGSIH, Tri;MATDOAN, Arsad;SAING, Zubair
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.12
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    • pp.1205-1214
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    • 2020
  • The poverty level in Buru Regency is still high, despite the relatively stable economic growth. For this reason, the purpose of this study was to (1) Identify the leading commodity in each district in Buru Regency; (2) Analyze the effect of road infrastructure and leading commodities on poverty. The findings show that the most sparsely populated district is Fena Leisela, with mangoes as the leading commodity. Pineapple, langsat, apple rose, cabbages, cashews, coffee, cashew, melon, and watermelon are the leading products in Air Buaya, Batabual, Waplau, Lolong Guba, Lilialy, Waelata, Namlea, Kaiely Bay, and Waeapo, respectively. Additionally, the results also indicate that road infrastructure and leading commodities have a significant effect on poverty alleviation in Buru Regency. It means that improving infrastructure and increasing leading commodities production reduce poverty in the region. Good road infrastructure can promote connectivity between regions so that it can accelerate and expand economic development. The provision of infrastructure that encourages connectivity will reduce transportation costs and logistics costs to increase product competitiveness and accelerate the economic movement. When the road infrastructure in Buru Regency improves and new roads are built, it can improve transportation access, it will reduce the living cost for the poor and increase income, and open up opportunities for the poor to benefit from economic growth.