• Title/Summary/Keyword: Expansion Method

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A Evaluation Technique for Reliability of Extra-High Voltage Cable Accessories using High Frequency Partial Discharge Measurement (고주파 부분방전 측정에 의한 초고압 접속함 신뢰성 평가 기술)

  • Sin, Du-Seong;Lee, Chang-Yeong;Kim, Chung-Sik;Jeon, Seung-Ik;Kim, Dong-Uk;Park, Wan-Gi
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.49 no.3
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    • pp.186-195
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    • 2000
  • In this paper, partial discharge (PD) measurement was performed to evaluate the quality of the cable joint and termination constructions. The resistive coupling technique for PD detection using resistivity of semiconducting layer of the cable in the accessories, such as joints and terminations. With high frequency PD (HEPD) measurement, an excellent sensitivity below 20pC could be achieved under unshielded condition. The localization of the defects in the accessories could be identified. During heating cycle, PDs were monitored and analyzed. At that time, the PDs were dependent on the temperature of the heating cycle and showed cyclic behaviors, which were attributed to local delamination of the interfaces, between epoxy unit and stress relief cone(SRC) and between SRC and cable, due to the difference of thermal expansion. As a conclusion, HFPD measurement technique was proven to be an effective diagnostic method for qualification of extra high voltage (EHV) cable accessories. With this technique, the optimal design of the components of the accessories could be verified not only in an early stage but also under operating condition. This technique would result in the improvement of the reliability of the EHV cable accessories.

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A Comparison of Flow Efficiency between To/From Ratio Method and Minimal Backward-Flow -Research for the Characterized Curriculum of Industrial Engineering- (Model전문대학 공업경영과 특성화 교육과정 연구)

  • 김영균;유정모;정종식;최동순;배상윤
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.20 no.44
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    • pp.377-391
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    • 1997
  • We consider the characterized curriculum of industrial engineering for training the excellent technician. We classified many kinds of jobs in the industry and information society and compared them with the curriculums of 13 junior colleges sampled randomly. Also we inquired the degree of relation of the technique qualification for graduates from industrial engineering to the current major subjects. For fostering the cultured individuals the community demands, we amended and looked into the current liberal arts course to supplement it. We analyzed the opinions of students, professors and experts from various circles through questionnaires, and then we set up the direction and the priority order for developing the curriculum for training the technician. According to the analyzed results, we presented the curriculum centering around customers and demanders and introduced it in detail. We are going to utilize developed curriculum, teaching methods by computers and practice methods step by step, and make expansion to industrial engineering of other colleges. Then we are planning to apply to the reeducation for graduates and the social education that contains the industrial human resources and the ordinary persons.

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Characteristics of Cathode material in SOFC (고체 전해질형 연료전지의 산소극 재료에 대한 연구)

  • Park, J.H.;Park, T.G.;Eom, S.W.;Kim, G.Y.;Moon, S.I.;Lim, H.C.;Lee, C.W.
    • Proceedings of the KIEE Conference
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    • 1995.07c
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    • pp.1051-1053
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    • 1995
  • Nowadays perovskite $La_{1-x}Sr_xMnO_3$ is preferred cathode material in Solid Oxide Fuel cell(SOFC). The $La_{1-x}Sr_xMnO_3$ with Sr contents ranging $x=0{\sim}1.0$ were prepared by a citrate method. These powders were characterized by usual means like TG/DTA, X-ray diffraction analysis. The samples used for measuring thermal expansion were prepared as pellets by cold pressing and subsequent sintering in air at $1200^{\circ}C$ for 5 hours. To measure the by-product of $La_{1-x}Sr_xMnO_3$ reacted with 8mol% YSZ, that samples were sintered at $1200^{\circ}C$ for 5 hours.

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The Relationship between Childcare Philosophy and Architectural Space of Communal Childcare Cooperative Nurseries (공동육아 협동조합 어린이집 보육철학과 건축공간의 관계성)

  • Yoo, Myoung-Hee
    • Journal of the Korean Institute of Educational Facilities
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    • v.19 no.2
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    • pp.41-50
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    • 2012
  • This study aims to analyze chlidcare philosophy and the architectural characteristics of communal childcare cooperative nurseries(parent cooperative childcare facilities), and also to examine their mutual relationship. The communal childcare cooperative is an ideal childcare method to break away from employee-supported childcare system and cooperatively solve childcare problems in the family community system. The child-rearing philosophy of the communal childcare can bring spontaneous and creative development amidst 'daily life' and 'play' by switching from knowledge and skill-oriented education and puts an emphasis on physical environments in child's growth. The features of architecture related the childcare philosophy derived from this study are as follows: the way of participation and self-help, the extension of spatial scope and focuses on outside space, architecture of house-like residence rather than educational facility, spatial 'overlapping' focusing on transitional space and multi-purpose space rather than spatial partitions, the pursuit of creativity through play is realized in the incompletion and unspecification of space evolving over time.

Evaluation of Thermal Dmage for Railway Weel (차륜에 대한 열손상 평가)

  • Kwon, Seok-Jin;Seo, Jung-Won;Lee, Dong-Hyong;Kim, Young-Kyu;Kim, Jae-Chul
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.966-970
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    • 2011
  • The thermo-mechanical interaction between brake block and wheel tread during braking has been found to cause thermal crack on the wheel tread. Due to thermal expansion of the rim material, the thermal cracks will protrude from the wheel tread and be more exposed to wear during the wheel/block contact than the rest of the tread surface. The wheel rim is in residual compression stress when is new. After service running, the region in the tread has reversed to tension. This condition can lead to the formation and growth of thermal cracks in the rim which can ultimately lead to premature failure of wheel. In the present paper, the thermal cracks of railway wheel, one of severe damages on the wheel tread, were evaluated to understand the safety of railway wheel in running condition. The residual stresses for damaged wheel which are applied to tread brake are investigated. Mainly X-ray diffusion method is used. Under the condition of concurrent loading of continuous rolling contact with rails and cyclic frictional heat from brake blocks, the reduction of residual stress is found to correlate well with the thermal crack initiation.

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A Semantic Analysis of the Indeterminacy in Contemporary Fashion - Focusing on Fashion Since 2000 - (현대 패션에 나타난 불확정성의 의미해석 - 2000년대 이후 패션을 중심으로 -)

  • Hwang, Hye-Jin;Kim, Min-Ja
    • Journal of the Korean Society of Costume
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    • v.62 no.5
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    • pp.1-15
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    • 2012
  • In a fast changing postmodern society, contemporary fashion is becoming more complicated and ambiguous along with other genres of art than ever before. This phenomenon reigning as a sociocultural paradigm can be defined as 'indeterminacy' and it means 'undecidability'. The purpose of this study is to clarify and analyze the indeterminate characteristics of contemporary fashion reviewing the theoretical background and the architectural formativeness as a comparative research. The core idea of deconstructivism dismantles a causal relationship between function and form in fashion and the conventional notion about clothes. Complexity theory, which is the study of chaotic dynamical systems, suggests the creative idea and concept of infinite possibilities on a formative method. Meanwhile, catastrophe theory of discontinuous change can be used as interpretative strategies for the process of deconstruction and reconstruction. As a result of this study, the indeterminacy of fashion can be analyzed into five semantic categories: irregularity, immateriality, randomness, complexity and changeability. The intrinsic value of the indeterminacy in contemporary fashion is the interaction with a sociocultural ideology and a technological environment as well as an expansion of formative expression. To conclude, it can be said that the indeterminacy in fashion is a new interpretation of the relationship among body and space, clothes and society.

Review on Application of Biosystem Modeling: Introducing 3 Model-based Approaches in Studying Ca Metabolism

  • Lee, Wang-Hee;Cho, Byoung-Kwan
    • Journal of Biosystems Engineering
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    • v.37 no.4
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    • pp.258-264
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    • 2012
  • Purpose: This review aims at introducing 3 modeling approaches classified into 3 categories based on the purpose (estimation or prediction), structure (linear or non-linear) and phase (steady-state or dynamic-state); 1) statistical approaches, 2) kinetic modeling and 3) mechanistic modeling. We hope that this review can be a useful guide in the model-based approach of calcium metabolism as well as illustrates an application of engineering tools in studying biosystems. Background: The meaning of biosystems has been expanded, including agricultural/food system as well as biological systems like genes, cells and metabolisms. This expansion has required a useful tool for assessing the biosystems and modeling has arisen as a method that satisfies the current inquiry. To suit for the flow of the era, examining the system which is a little bit far from the traditional biosystems may be interesting issue, which can enlarge our insights and provide new ideas for prospective biosystem-researches. Herein, calcium metabolic models reviewed as an example of application of modeling approaches into the biosystems. Review: Calcium is an essential nutrient widely involved in animal and human metabolism including bone mineralization and signaling pathways. For this reason, the calcium metabolic system has been studied in various research fields of academia and industries. To study calcium metabolism, model-based system analyses have been utilized according to the purpose, subject characteristics, metabolic sites of interest, and experimental design. Either individual metabolic pathways or a whole homeostasis has been modeled in a number of studies.

A Study on Vitalizing Plans of Extension Remodeling for Apartment Housings (공동주택 증축 리모델링 활성화 방안에 관한 연구)

  • Cho, Jae-Yong;Lee, Kuen-Woo;Yoo, Hyun-Seok;Kim, Young-Suk
    • Korean Journal of Construction Engineering and Management
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    • v.13 no.4
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    • pp.33-47
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    • 2012
  • 548 thousand apartment houses of Seoul has been used over 15 years and remodeling is available. It is 42% of the overall apartment houses currently and it is assumed to increase to 800 thousand in 2015. The maintenance work is divided to reconstruction and remodeling. Due to the regulations of the government, expansion remodelling has been the most considered alternative. However, 75% of the extension remodelling, yet, are in the preliminary phases. Thus, this study suggests factors hampering the vitalization of extension remodelling and solutions for each factor by means of Delphi analysis method.

Nursing Student's Experiences in Team Based Simulation Learning (간호학생의 팀기반 시뮬레이션 학습경험)

  • Kang, Hee-Young;Choi, Eun-Young;Kim, Hae-Ran
    • The Journal of Korean Academic Society of Nursing Education
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    • v.19 no.1
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    • pp.5-15
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    • 2013
  • Purpose: The purpose of this study was to explore nursing students experiences in team based simulation learning. This study was based on a phenomenological research methodology. Methods: Fourteen nursing students participated in this study. The students gave in depth interviews and wrote reflective journals after participating in a team based simulation learning program, which was provided at C University in Gwangju for 8 weeks, 2011. These data were analyzed using Van Kaam's method. Results: 21 sub-themes and 9 themes were elicited from 55 significant statements. They were classified into 3 categories such as : 'First exposed to lessons on how Burden', 'the enjoyment of team based simulation learning', 'expansion of the clinical competence'. Conclusion: Teaching and learning strategy that combines a variety of simulation training to nursing students to develop critical skills to improve their care to give and take advantage of simulation training supplement is advised.

Elasticity solution and free vibrations analysis of laminated anisotropic cylindrical shells

  • Shakeri, M.;Eslami, M.R.;Yas, M.H.
    • Structural Engineering and Mechanics
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    • v.7 no.2
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    • pp.181-202
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    • 1999
  • Dynamic response of axisymmetric arbitrary laminated composite cylindrical shell of finite length, using three-dimensional elasticity equations are studied. The shell is simply supported at both ends. The highly coupled partial differential equations are reduced to ordinary differential equations (ODE) with variable coefficients by means of trigonometric function expansion in axial direction. For cylindrical shell under dynamic load, the resulting differential equations are solved by Galerkin finite element method, In this solution, the continuity conditions between any two layer is satisfied. It is found that the difference between elasticity solution (ES) and higher order shear deformation theory (HSD) become higher for a symmetric laminations than their unsymmetric counterpart. That is due to the effect of bending-streching coupling. It is also found that due to the discontinuity of inplane stresses at the interface of the laminate, the slope of transverse normal and shear stresses aren't continuous across the interface. For free vibration analysis, through dividing each layer into thin laminas, the variable coefficients in ODE become constants and the resulting equations can be solved exactly. It is shown that the natural frequency of symmetric angle-ply are generally higher than their antisymmetric counterpart. Also the results are in good agreement with similar results found in literatures.