• Title/Summary/Keyword: Power System Education

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Indicators and Planning Features of Ecologically Based Urban Regeneration -Cases from Hamburg, Germany and Copenhagen, Denmark (생태기반형 도시재생의 계획지표 및 특성에 관한 연구 -독일 함부르크와 덴마크 코펜하겐 사례를 중심으로)

  • Rhee, Bum-Hun;Chang, Dong-Min
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.10
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    • pp.158-166
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    • 2018
  • Contrary to urban development, urban regeneration is a process of land development through conservation, restoration, and management. In particular, ecologically based urban regeneration is an attempt to improve the quality of life in an area, establish a stable settlement space, and revitalize the local economy by considering the ecological environment. In this regard, the objectives of this study were to establish theoretical concepts and analyze the successful foreign cases of ecologically based urban regeneration, and propose a direction of socio-economic regeneration along with the physical-environmental regeneration of urban areas in Korea. The study results suggest the following. First, strategies must be developed to coordinate public transportation, such as buses and subways, by considering the importance of bicycle riders, along with the sustainable-commuting system. Second, both the importance of planning parks and trails around water systems in various scales while maintaining the existing natural environment as well as using natural elements, such as electric vehicles and wind-power generation systems, were emphasized. Third, urban regeneration for increased energy efficiency requires specific architectural planning and facilities. Fourth, education and research for easy access by the public, as well as public-private partnership, will be needed in the regeneration process.

Analysis of Vibration Characteristics for a Molded Dry-type Potential Transformer (몰드형 건식 계기용 변압기 진동 특성 분석)

  • Kim, Moosun;Jang, Dong Uk;Kim, Seung Mo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.3
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    • pp.209-214
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    • 2017
  • Most of the present potential transformers of train vehicles are of the oil-type filled with insulating oil and are susceptible to problems such as explosion due to the increase in the internal pressure during train operation and poor reliability near the end of their life cycle. As a solution to this problem, it is necessary to develop a molded dry-type potential transformer with excellent pressure-resistance performance using insulating resin. In order to localize the product, the Korea Railroad Research Institute has been developing a molded dry-type potential transformer. As part of this research, it is necessary to analyze the vibration characteristics of the developed product and to check the transformer performance in a vibration environment. In this study, a resonance test and simulated long-term life test of the developed product were conducted according to the KS R 9144 and IEC 61373 standards, respectively, which are vibration test methods for railway vehicle parts. Their natural frequencies were analyzed by comparing the results of the numerical modal analysis and resonance test, in order to confirm their adherence to the standards. Also, the performance test after the simulated long-term life test confirmed that the operation of the developed transformer was not problematic even in a long-time vibration environment.

Numerical Analysis of Resin Filling Process for a Molded Dry-type Potential Transformer (몰드형 건식 계기용 변압기 제작을 위한 수지 충진 해석 연구)

  • Kim, Moosun;Jang, Dong Uk;Kim, Seung Mo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.12
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    • pp.511-517
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    • 2016
  • Current oil-type potential transformers for trains are filled with insulating oil, which could have problems like explosions due to rising inner pressure during train operation. Therefore, mold and dry-type potential transformers are being developed to prevent explosions. One problem in manufacturing mold-type transformers is preventing void formation around the coiled core inside the mold during epoxy filling, which could cause an electrical spark. Micro voids can remain in the resin after filling, and macro voids can occur due to the structure shape. A transformer that is being developed has a cavity at the junction of the core and the coil for better performance, and when highly viscous epoxy flows inside the cavity channel, macro voids can form inside it. Therefore, in this study, the free-surface flow of the mold filling procedure was analyzed numerically by applying the VOF method. The results were used to understand the phenomena of void formation inside the cavity and to modify the process conditions to reduce voids.

Influence of Co-sputtered HfO2-Si Gate Dielectric in IZO-based thin Film Transistors (HfO2-Si의 조성비에 따른 HfSiOx의 IZO 기반 산화물 반도체에 대한 연구)

  • Cho, Dong Kyu;Yi, Moonsuk
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.2
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    • pp.98-103
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    • 2013
  • In this work, we investigated the enhanced performance of IZO-based TFTs with $HfSiO_x$ gate insulators. Four types of $HfSiO_x$ gate insulators using different diposition powers were deposited by co-sputtering $HfO_2$ and Si target. To simplify the processing sequences, all of the layers composing of TFTs were deposited by rf-magnetron sputtering method using patterned shadow-masks without any intentional heating of substrate and subsequent thermal annealing. The four different $HfSiO_x$ structural properties were investigated x-ray diffraction(XRD), atomic force microscopy(AFM) and also analyzed the electrical characteristics. There were some noticeable differences depending on the composition of the $HfO_2$ and Si combination. The TFT based on $HfSiO_x$ gate insulator with $HfO_2$(100W)-Si(100W) showed the best results with a field effect mobility of 2.0[$cm^2/V{\cdot}s$], a threshold voltage of -0.5[V], an on/off ratio of 5.89E+05 and RMS of 0.26[nm]. This show that the composition of the $HfO_2$ and Si is an important factor in an $HfSiO_x$ insulator. In addition, the effective bonding of $HfO_2$ and Si reduced the defects in the insulator bulk and also improved the interface quality between the channel and the gate insulator.

On-Land Seismic Survey of Korea (한국의 육상 탄성파탐사)

  • Kwon, Byung-Doo
    • Economic and Environmental Geology
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    • v.39 no.4 s.179
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    • pp.441-450
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    • 2006
  • The on-land seismic survey in Korea was begun in mid-1960s. Kim et al.(1967) of Korea Geological Survey reported on the result of gravity and seismic reflection surveys conducted in the Pohang area for the period of 1963-64 to assess its possibility of oil entrapment. Hyun and Kim (1966) carried out a refraction survey on the tunnel wall. Since then, the KGS geophysicists had conducted seismic surveys on Kyungsang sedimentary basin as a main project for several years. In 1970s, on-land seismic surveys had been conducted for various purposes such as site investigation for the nuclear power plants and industrial complex, exploration for ground water, mineral resources and underground tunnel. The first reflection survey with CMP acquisition was attempted in 1978 by using a digital recording system. But most of on-land seismic surveys had employed the refraction method until 1980s. In 1990s, high resolution reflection and various borehole seismic surveys such as tomography, uphole, downhole, cross-hole methods have been attempted by universities and engineering companies. The applications of on-land seismic surveys have been enlarged for both academic and industrial purposes such as investigation of geologic structure of the fault and tidal flat area, construction of highway, railroad and dam, geothermal energy and mineral resource exploration, environmental assessment for waste disposal sites and archaeological investigations. In 2002, the first crustal seismic survey was carried out on the profile of 294km length across the whole peninsular. It is expected that the advanced technology and experience acquired through offshore seismic surveys, which have been conducted in continental shelf of Korea and foreign oil fields, will stimulate the more active on-land seismic explorations.

Ground of the revolutionary change in early 20C American Mathematics (20세기 초 미국수학계의 혁명적변화의 바탕)

  • Lee, Sang-Gu;Hwang, Suk-Geun;Cheon, Gi-Sang
    • Journal for History of Mathematics
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    • v.20 no.3
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    • pp.127-146
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    • 2007
  • From 1876 to 1883, British mathematician James Joseph Sylvester worked as the founding head of Mathematics Department at the Johns Hopkins University which has been known as America's first school of mathematical research. Sylvester established the American Journal of Mathematics, the first sustained mathematics research journal in the United States. It is natural that we think this is the most exciting and important period in American mathematics. But we found out that the International Congress of Mathematicians held at the World's Columbian Exposition in Chicago, August 21-26, 1893 was the real turning point in American's dedication to mathematical research. The University of Chicago was founded in 1890 by the American Baptist Education Society and John D. Rockefeller. The founding head of mathematics department Eliakim Hastings Moore was the one who produced many excellent American mathematics Ph.D's in early stage. Many of Moore's students contributed to build up real American mathematics research power in early 20 century The University also has a well-deserved reputation as the "teacher of teachers". Beginning with Sylvester, we analyze what E.H. Moore had done as a teacher and a head of the new department that produced many mathematical talents such as L.E. Dickson(1896), H. Slaught(1898), O. Veblen(1903), R.L. Moore(1905), G.D. Birkhoff(1907), T.H. Hilderbrants(1910), E.W. Chittenden(1912) who made the history of American mathematics. In this article, we study how Moore's vision, new system and new way of teaching influenced American mathematical society at early stage of the top class mathematical research. and the meaning that early University of Chicago case gave.

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Reconstruction of the Experience of Single Mothers in Poverty -The Meaning of Self-Sufficiency, Welfare Dependency, and Work- (빈곤 여성 한부모 자활 경험의 재구성 -자활, 복지의존, 일의 의미-)

  • Chong, Hye-Suk
    • Korean Journal of Social Welfare
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    • v.67 no.4
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    • pp.251-277
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    • 2015
  • This qualitative study is designed for the reconstruction of the experience of single mothers in poverty based on the bottom-up approach. Welfare dependency is identified as vital help to protect their own and children's lives, through their stories telling that welfare services provided by government and community take care of them "in place of their husbands", and "raise them up by hand." What is self-sufficiency to them is more of a process-orientation through welfare dependency than a state out of it, and a way to look through building their self-esteem and working to discover their self-worth except their economic power. Restoring their potential to self-sufficiency through dealing with their psycho-social stresses and expanding services for them related to child-care(education) and occupation ability development for long-term self-sufficiency, rather than hasty focusing on welfare exit, should be built on the foundation of helping them self-sufficient. In order for the self-sufficiency program to overcome the participant's images of "subordination and stigma" and to convey the original meaning of "welfare to work", the performance and evaluation system of self-sufficiency programs that reflects the insider's perspectives on their participation motive and process, and the self-sufficiency program customized for their needs and interests should be encouraged to develop.

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A Case Study on Quasi-Economic Integration in the Cheju Broiler Industry. (제주브로일러 산업의 유사경제 통합에 관한 사례연구)

  • 박영인
    • Korean Journal of Poultry Science
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    • v.15 no.1
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    • pp.53-60
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    • 1988
  • The purpose of this presentation is to review the situation of the Cheju broiler industry peculiarized with the integrated production and marketing system to some degree, which is not prevailed in the whole broiler industry in Korea, so as to study the case of the Cheju industry from the viewpoint of an economic integration. The economic integration in the broiler industry is grouped into three patterns: non-integration, quasi-integration and complete integration, which generally exist under the different type of market competition. The quasi-integration tends to be formed at all phases where the complete integration is not fully implemented, but the non-integration has begun to change its nature into partially integrated structure. The Cheju broiler industry is characterized by the geographical location of isolated market so that factor supplies and broiler products are marketed in the different conditions from those of mainland Korea, somewhat in an oligopolistic pattern. It was since early 1980's that the industry successfully had three dressing plants merged into one by virtue of entire growers ownership, which opened an era of an integrated industry centered on the function of dressing birds. The case of Cheju broiler industry today is to be referred to as a typical quasi-integration which is coordinated the function between growing and dressing birds directly and extended the functional cooperation to distribution of products indirectly, while factor supplies are traded independently. As a result of a quasi-integration, the growers are able to receive a fixed price set by the dressing plant of growers that has the power to adjust the supply of and demand for broilers produced and consumed in the Island. There are some problems, however, in the integration of the Cheju broiler industry, stemming mainly from the process of the structure change, : 1) the difficulty of controlling the production of broilers, 2) continuing pressure on the integration by non-integrated sectors, 3) the challenge on the stabilized broiler market from the mainland, 4) limited effectiveness of consumer education activities, and 5) lack of leadership for the industry development through integration. It is projected that the partially integrated Cheju broiler industry will be continually developed toward the direction of a complete integration in due course, as the currently independent supply sectors are to be backward integrated. The case of the Cheju broiler integration, therefore, could be used as a reference for making the whole broiler industry in Korea develop toward the integrated structure in the future.

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A Study for New Paradigm Settlement on Business Security Management: Focus on Global Business (산업보안관리에 관한 뉴패러다임의 정립: 글로벌 비즈니스를 중심으로)

  • Yu, Hyung-Chang
    • Korean Security Journal
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    • no.39
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    • pp.355-386
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    • 2014
  • Current business environment asks the fundamental changes about business security. The essences of these changes are that the security management of today's global business is important task of managers and the security practitioner is professional who needs very specialized education and training with business thinking. Rapid process of globalization of global village tore down the business limit that was restricted on the geological areas' limitation. Rapid business environments' change that is driving depends on development of science and technology with globalization needs new paradigm to keep business continuity. With the process of globalization, Korea, which importance is gradually increasing in the national economy, has trade dependent economic system, which keeps power of national economy through trade, so Korean economic tendency is accelerating. To keep competitiveness in global market, new strategy that is different with existing domestic business management is necessary. That is, capacity of coping with outside risk in domestic business management is established in some degree, but business activities in foreign countries faces at numerous unexpected risks that differ from country to country such as difference with the custom, changes of corporate governance etc. To cope with these new risks effectively, new paradigm for business risk is necessary. Especially, flexibility of thinking like new paradigm is necessary to cope with new security risk effectively. To cope with security risk that occurs in the new business environment effectively and competes against international company in global market, company management and members' changes of cognition about security and innovative changes in security policy is necessary. In the basement of these changes, there is expansion of business security tasks, improvement of report line, enhancement of professionalism and status of security officers, variation of hands-on workers and increasing of investment to the security etc.

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Implementation of the Urban Development Projects in Ulaanbaatar (도시개발 여건을 고려한 울란바타르 건설사업 참여방안)

  • Jeong, Yeun-Woo;Seong, Jang-Hwan
    • Land and Housing Review
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    • v.3 no.4
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    • pp.357-367
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    • 2012
  • The efficient business scheme were suggested with the consideration of the local development condition at Ulaanbaatar. Major findings of the study were presented as follows. First, high level of education and the underground resources are presented as the merits of Mongolia. On the other side, the defects are limited domestic demands of 2.6 millions of population and the insufficiency of the infrastructure. The improvement of the infrastructures like roads, water & sewage, electric power, and heating is urgent while the development pressure of Ulaanbaatar is expected to be high due to the continuous inflow of population. Secondly, the Mongolian land system consists of the right of ownership, lease and use, therefore there are some differences among the right of land. Thirdly, definite business scheme to sell land in lots and to sell buildings in lots are suggested which are actual methods to participate in the development project in Ulaanbaatar. Moreover, enhancing the possibility to sell the lands, fixing the proper sale price to secure the profit, finding the proper buyer for the profitable lands, investing of quota and guaranteeing of granting the principal and interest by the Mongolian government, etc. are presented as consideration when participate in projects.