• Title/Summary/Keyword: 2 order system

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The Electrical Insulation Characteristics of HTS SMES (초고온초전도 SMES의 절연특성)

  • Cheon, Hyeon-Gweon;Choi, Jae-Hyeong;Kim, Hae-Jong;Seong, Ki-Chul;Kim, Sang-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.623-626
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    • 2005
  • Toward the practical applications, on operation of conduction-cooled HTS SMES at temperatures well below 77 K should be investigated, in order to take advantage of a greater critical current density of HTS and considerably reduce the size and weight of the system. Recently, research and development concerning application of the conduction-cooled HTS SMES that is easily movement are actively progressing in Korea. Electrical insulation under cryogenic temperature is a key and an important element in the application of this apparatus. Using multi wrapped copper by polyimide film for HIS SMES, the breakdown characteristics of models for turn-to-turn, that is surface contact model, were investigated under ac and impulse voltage at 77 K. A material that is Polyimide film (Kapton) 0.025 mm thickness is used for multi wrapping of the electrode. Statistical analysis of the results using Weibull distribution to examine the wrapping number effects on breakdown voltage under ac and impulse voltage in $LN_2$ was carried.

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A Study on Optimal Planning of Sustainable Rural Road Path based on Infrastructure for Green-Tourism and Public Service (그린투어리즘 및 공공서비스 기반의 지속가능한 농촌도로노선의 최적계획에 관한 연구)

  • Kim, Dae-Sik;Chung, Ha-Woo
    • Journal of Korean Society of Rural Planning
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    • v.11 no.1 s.26
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    • pp.1-8
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    • 2005
  • The purpose of this study is to develop a simulation model of rural road path for infrastructure of green-tourism and public service in rural areas. This study makes an objective function for moving cost minimization considering car travel time according to road characteristics, which can route the optimal shortest road paths between the center places and all rear villages, based on GIS coverages of road-village network for connecting between center places and rural villages as input data of the model. In order to verify the model algorithm, a homogeneous hexagonal network, assuming distribution of villages with same population density and equal distance between neighborhood villages on a level plane area, was tested to simulate the optimal paths between the selected center nodes and the other rear nodes, so that the test showed reasonable shortest paths and road intensity defined in this study. The model was also applied to the actual rural area, Ucheon-myun, which is located on Hoengsung-gun, Kangwon-do, with 72 rural villages, a center village (Uhang, 1st center place) in the area, a county conte. (Hoengsung-eup, 2nd center place), and a city (Wonju, 3rd center place), as upper settlement system. The three kinds of conte. place, Uhang, Hoengsung-eup, and Wonju, were considered as center places of three scenarios to simulate the optimal shortest paths between the centers and rural villages, respectively. The simulation results on the road-village network with road information about pavement and width of road show that several spans having high intensity of road are more important that the others, while some road spans have low intensity of road.

3-D Perspectives of Atmospheric Aerosol Optical Properties over Northeast Asia Using LIDAR on-board the CALIPSO satellite (CALIPSO위성 탑재 라이다를 이용한 동북아시아 지역의 대기 에어러솔 3차원 광학특성 분포)

  • Lee, Kwon-Ho
    • Korean Journal of Remote Sensing
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    • v.30 no.5
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    • pp.559-570
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    • 2014
  • Backscatter signal observed from the space-borne Light Detection And Ranging (LIDAR) system is providing unique 3-dimensional spatial distribution as well as temporal variations for atmospheric aerosols. In this study, the continuous observations for aerosol profiles were analyzed during a years of 2012 by using a Cloud-Aerosol LIDAR with Orthogonal Polarization (CALIOP), carried on the Cloud-Aerosol LIDAR and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. The statistical analysis on the particulate extinction coefficient and depolarization ratio for each altitude was conducted according to time and space in order to estimate the variation of optical properties of aerosols over Northeast Asia ($E110^{\circ}-140^{\circ}$, $N20^{\circ}$ $-50^{\circ}$). The most frequent altitudes of aerosols are clearly identified and seasonal mean aerosol profiles vary with season. Since relatively high particle depolarization ratios (>0.5) are found during all seasons, it is considered that the non-spherical aerosols mixed with pollution are mainly exists over study area. This study forms initial regional 3-dimensional aerosol information, which will be extended and improved over time for estimation of aerosol climatology and event cases.

The Effects of Shoes with Rolling Feature on the Foot Reaction Force and Pronation (신발의 굴림 특성이 족저반력 및 회내운동에 미치는 영향)

  • Shin, Hak-Soo
    • Korean Journal of Applied Biomechanics
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    • v.17 no.3
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    • pp.189-195
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    • 2007
  • The purpose of this study was to analyze the effects of shoes with curved out-sole on the pressure, reaction force(sum of pressure) on foot and relations between the rolling speeds and pronation of foot. The foot pressure, reaction force and pressure center on the foot surface of shoe were measured with NOVEL padar system, and 3 type shoes were used to compare the position and speed of pressure center and the foot reaction force, which were s(target) shoe with soft cushions in middle part of out-sole and curved out-sole, m shoes with two type- soft, hard, hardness out-sole and curved out-sole and n shoes with flat out-sole. The subjects were 13 female university students, had weared the 3 type shoes for 6 weeks on two-weeks shifts for adaptation before experiment and put on 3-type shoes repeatedly and randomly and walked on treadmill with 3.5km/h and 80 steps/min. The data were captured with 30Hz and readjusted with 5kgf threshold reaction force. The results can be summarized as follow. 1. There were no difference in maximum reaction force on initial contact period and total foot impact, but statistical difference in maximum reaction force on takeoff period : s, m, n in ascending order. 2. There were some difference in rolling speeds for support periods. At initial contact, the rolling speed of s shoes was fastest but at periods between first and second maximum reaction force, that of m shoes fastest. 3. There was a negative relation between rolling speeds and the length of lever arm on initial reaction force related to pronation. It seems shoes with various curved shapes and hardness could make effects on the rolling features and the rolling speed also have some relationships with walking efficiency, absortion of impact and pronation.

A Study on the Components of Teacher In-Service Training Program to Improve the Professionalism in the Elementary Environmental Education (초등환경교육의 전문성 신장을 위한 교사 연수 프로그램의 구성 요소 탐색)

  • Lee, Sung-Hee;Choi, Don-Hyung
    • Hwankyungkyoyuk
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    • v.20 no.2
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    • pp.54-66
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    • 2007
  • The purpose of this study is to find identity of the elementary environmental education and inquire elements of professionalism in environmental education that elementary teachers should have. This study performed a half-structured interview in twice to the eight of elementary teachers who completed the environmental education curriculum course in a graduate school or participated in the teacher training program before. As a result, this study found that the identity of the elementary environmental education consists of the unification comprehending various subjects, the well-rounded sensitivity balancing intellectual, emotional and behavioral aspects, and the grounding in forming environmentally friendly living-habit and academic basis of environments. Moreover, this study found that the teacher training program for the specialty of the elementary environmental teachers should comprise of the following twelve components: the knowledge of overall environmental curriculum, environmental life guidance and environmental classroom management, environmental teaching skills and function, the passion and commitment about environmental education, environmental sensitivity, understanding of education studies, the values and attitude about environment, environmental behavior, understanding the relationship between environmental psychology and developing stage of child, the general education and communication/cooperation with colleagues or local community, understanding of the role as an teacher for the elementary environmental education. More importantly, it would be very crucial that the teachers themselves who are the main body of education system should recognize the their role as the professionals in order to improve the quality of education.

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An Empirical Study of Organizational Innovation Practice in Electronic and Electrical Industry in the Greater Pearl River Delta (GPRD)

  • Wong, Shui Yee;Chin, Kwai Sang
    • International Journal of Quality Innovation
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    • v.7 no.2
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    • pp.50-68
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    • 2006
  • Innovation fuels organizations evolving them to withstand rapid changes in markets and challenges from competition. While diversified concepts of innovation are examined, a generic framework for managing organizational innovation is established to portray the notion in a methodical approach. Substantiation of the determinants for organizational innovation is carried out in order to examine the framework against the practical situation. Subsequently, expectations and actual accomplishments of the determinants for organizational innovation from the industry are determined so as to understand the industrial view towards the framework. This paper summarizes the empirical findings of a survey of organizational innovation with a sample of 208 electronic and electrical manufacturing companies in the Greater Pearl River Delta (GPRD), China. On one hand, the survey findings confirm the readiness of the generic framework from the practical perspective of the industry. On the other hand, rankings are obtained for the expected importance and company accomplishment of the determinants for organizational innovation, namely in the areas of management leadership and commitment, employee capability and attitude and strategy development for innovation. The improvement area is also verified by the shortcomings of the expectation in comparison to the company accomplishment in each determinant. Meanwhile, it is believed that a directional attitude towards the determinants can facilitate the accomplishment of the determinants of organizational innovation. Further results will be generated from a more in-depth analysis of variables. The confirmed framework will be further developed into an assessment system for organizational innovation with the support of best practices in each determinant.

Analysis on Expenditure Structures and Impact Factors of Household Transportation Cost (국내 가구 교통비의 지출 구조 및 영향요인 분석)

  • Han, Sang-Yong;Lee, Jae-Hun
    • Journal of Korean Society of Transportation
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    • v.28 no.2
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    • pp.33-43
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    • 2010
  • The objective of this paper is to analyze expenditure structures and impact factors of household's transportation cost in order to provide policy-maker with quantitative and economic information for reducing household's transportation costs, using 1995-2007 household survey data. For this purpose, this study performed various economic analysis, including econometric regression analysis and income re-distributional effects. The four models were separately estimated with dependent variable (personal and public costs, public transit and private car costs) and independent variables (family, employ, age, education, cars, household income, region dummy variable). In addition, We analyzes impacts of transport policy instruments on the transportation expenditure. These instruments include changes of oil price and public transit fare, reform of public transport system, and extension of subway facilities. Finally, income re-distributional effects before and after transportation expenditure, using Pechman-Okner (PO) index and Wolfson index.

γ-aminobutyric Acid Content in House Rat and Fowl Brain (집쥐와 닭 뇌의 γ-Aminobutyric acid 함량)

  • Huh, Rhin Sou
    • Korean Journal of Veterinary Research
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    • v.11 no.1
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    • pp.59-63
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    • 1971
  • Current interest in ${\gamma}$-aminobutyric acid (GABA) has arisen from the convergence of several independent line of investigation leading to the demonstration that this and related substances are normal products of brain metabolism and that GABA has an important physiological action upon brain function as well as upon certain peripheral nervous structures. The interest for neurophysiologists has been enhanced by the importance of the discovery for the role of humoral mediator of synaptic transmission or regulator of neuronal activity in the central nervous system, particularly if it may shed some elight upon the nature of central inhibitory processes. In accordance with such an interest and importance, this work was performed in order to standardize the normal content as a preliminary investigation of so-called night active and daytime active animals GABA content in their brains when they are exposed to light and darkness. The method, through which the estimation has made in this work, was paper chromatographic method developed by Maynert and Klingman for the estimation of GABA content in animal tissues. The results obtained are summerized as follows: 1) GABA content in the cerebral cortex of house rat ranged from 90 to $310{\mu}g/gm$ of wet weight. 2) The content of GAGA ranging from 130 to $510{\mu}g/gm$ of wet weight was occurred from midbrain of the rat. 3) GABA content was ranged from 30 to $150 {\mu}g/gm$ of wet weight of the rat cerebellum. 4) The contents of fowl cerebral cortex, midbrain, and cerebellum are estimated as ranging 230-590, 250-620, $50-280{\mu}g/gm$ of wet weight, respectively. As a result, it may be concluded that among three brain tissues of both animals the midbrain is the highest region in GABA content. Fowl brain, on the other side, contains more higher GABA content than the house rat brain does.

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Enhancement of Library Internship Reflecting Participants' Opinions based on Activity Theory (활동이론을 적용한 사서인턴십 개선 방안 연구 - 인턴십 참여자의 관점에서 -)

  • Park, Zi-young;Park, Sung-jae
    • Journal of the Korean Society for Library and Information Science
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    • v.51 no.1
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    • pp.307-332
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    • 2017
  • The purpose of this study is to identify contradictions in library internship, and address them. As a case study, students who were enrolled in the internship class opened in the 2016 fall semester in a university in Seoul were interviewed. Through applying Activity Theory, the process of internship and contradictions presented in its process were analyzed. The findings indicate that students were satisfied with their internship experience. The internship experience also makes positive impacts on students in terms of understanding the library and information science and deciding their future career as a librarian. Such contradictions as internship duration, operation of the internship process, level of participation or practice, and overlap of part-time experience in a library were identified. This study suggests to make the internship systematic in order to address the contradictions through that all parties in internship are actively participated in internship and that they share information related with the internship.

Development and evaluation of a model for management of plant pests in organic cucumber cultivation

  • Ko, S.J.;Kang, B.R.;Kim, D.I.;Choi, D.S.;Kim, S.G.;Kim, H.K.;Kim, H.J.;Choi, K.J.;Kim, Y.C.
    • Korean Journal of Organic Agriculture
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    • v.19 no.spc
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    • pp.263-266
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    • 2011
  • Crop protection strategies in organic horticulture aim to prevent insect pest and plant disease problems through utilization of non-chemical based control means. In order to develop a model for management of plant diseases and insects in organic cucumber cultivation, we compared efficacies between chemical pesticide spraying system and biological control means in semi-forcing and retarding cucumber cultivation during 2005 and 2006. Conventional chemical spray program using various chemical pesticides was applied 5 - 10 days intervals, while two different non-chemical pesticide application programs using two formulated biopesticides Topseed$^{TM}$ and Q-fect$^{TM}$, Suncho$^{TM}$, and Sangsungje$^{TM}$ (biocontrol agents 1) and using egg-yolk and cooking oil(EYCO), Bordeaux mixture, Suncho$^{TM}$, and Sangsungje$^{TM}$ (biocontrol agents 2) were applied 5 - 7 days intervals during entire cucumber cultivation period. Efficacy of both biocontrol agents programs was effective to comparable to conventional chemical pesitice spray program to control plant diseases such as powdery mildew and downy mildew as well as insect pests such as aphids and thrips which are known as major threats in cucumber organic cultivation. In this study, we established and evaluated an effective and economic crop protection strategy using various biological resources can be used to control plant diseases and pests simultaneously in organic cucumber cultivation field.