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검색결과 138건 처리시간 0.032초

RF 감지 방식 on-line 케이블 접속재 진단 (On-line Test Equipment for Cable Joint by RF Sensing)

  • 이왕하;이성희;정희돈;김덕규;이동영
    • 대한전기학회논문지:전력기술부문A
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    • 제52권11호
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    • pp.661-667
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    • 2003
  • It has little possibility that a cable causes any problem in electric power facilities. But when a trouble occurs in cable or cable joint, the damage is very severe. The main causes of the cable defections are bad cable making procedure, poor cable operation and deterioration according to the years. There are some cases to have potential problems due to many cable connection points, because of short length of cable, especially in 154㎸ system. In this study, novel method to measure partial discharge in cable joints is proposed and the effectiveness and the reliability of the proposed method is shown through experiment results of field.

Towards alleviation of the digital divide and poverty through land information

  • Liou, Jae-Ik
    • 대한공간정보학회지
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    • 제10권5호
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    • pp.29-43
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    • 2002
  • Accesses to lands, houses, the Internet and other utilities are regarded as basic human needs to escape poverty and are required to recognize the relationships between the digital divide and socio-economical inequality. The digital divide might not be a single technical disparity, but stems from a complicated mixture of economic and socio-technical symptoms of inequality. There is growing awareness of scrutinizing causal mechanisms between the digital divide and poverty since combating poverty could be a primary step to mitigate the digital divide. In this paper, the Hexad model is proposed to explicate poverty interpretation by using 6 parameters as a major tool for partly assisting in poverty monitoring system in connection with land information. A solution model of the Internet is suggested to break the digital divide. It expounds a conceptual framework and new idea for poverty management to notify spatio-temporal locations of poor actors and geography of the digital divide when efforts of poverty eradication hinge on understandings of geographic location of digital disadvantaged groups through parcel-based land information.

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마이크로컴퓨터를 이용(利用)한 정규확률군(正規確率群) 분석함수(分布函數)의 근사계산(近似計算)에 관한 연구(硏究) (Approximations for the Normal Family Distribution Function Using Micro Computer)

  • 민성기;손혜숙;윤덕균
    • 품질경영학회지
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    • 제14권2호
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    • pp.47-54
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    • 1986
  • A different kind of approximation has been developed in connection with calculation of the normal family distributions in digital computer. These approximations usually employ polynomial expressions. They give quite high accuracy, sometimes only within definite limits on the values of the variable. Outside these limits they may give quite poor approximations. In this paper we compare these approximations by criteria of C.P.U. time and accuracy using micro computer. Approximation formulas given by Zelen and Severo (1984) are proven to give the most accurate results within allowable C.P.U. time.

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Mesh distortion sensitivity of 8-node plane elasticity elements based on parametric, metric, parametric-metric, and metric-parametric formulations

  • Rajendran, S.;Subramanian, S.
    • Structural Engineering and Mechanics
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    • 제17권6호
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    • pp.767-788
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    • 2004
  • The classical 8-node isoparametric serendipity element uses parametric shape functions for both test and trial functions. Although this element performs well in general, it yields poor results under severe mesh distortions. The distortion sensitivity is caused by the lack of continuity and/or completeness of shape functions used for test and trial functions. A recent element using parametric and metric shape functions for constructing the test and trial functions exhibits distortion immunity. This paper discusses the choice of parametric or metric shape functions as the basis for test and/or trial functions, satisfaction of continuity and completeness requirements, and their connection to distortion sensitivity. Also, the performances of four types of elements, viz., parametric, metric, parametric-metric, and metric-parametric, are compared for distorted meshes, and their merits and demerits are discussed.

고기능성 부품가공용 지능형 연삭시스템 연구개발 현황 (Development of Inteligent Grinding System far High Performance Part)

    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2002년도 춘계학술대회 논문집
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    • pp.46-51
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    • 2002
  • A grinding technology is very essential to finish the surface of IT and BT industrial application parts such as wafer, optical connection part and lenses etc. However the finding machine has bead depended on imports. Especially, it is completely imported for machining high precision part relevant to domestic electric and communicational industries. The amount to import grinding machine is about $110milions. It takes about 35% of total import amount of all the machine tools. A domestic finder manufacturer is a very small-scaled bussinessman and research facilities is poor. Recently, it is increasing to demand high speed and precision grinding technology because it brings cost down and value added up. Its further study will be something related to inteligent grinding system fur value added and high precision part. It will make domestic grinding technology to its advanced country level.

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Expanding roles of centrosome abnormalities in cancers

  • Soohyun Song;Surim Jung;Mijung Kwon
    • BMB Reports
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    • 제56권4호
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    • pp.216-224
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    • 2023
  • Centrosome abnormalities are hallmarks of human cancers. Structural and numerical centrosome abnormalities correlate with tumor aggressiveness and poor prognosis, implicating that centrosome abnormalities could be a cause of tumorigenesis. Since Boveri made his pioneering recognition of the potential causal link between centrosome abnormalities and cancer more than a century ago, there has been significant progress in the field. Here, we review recent advances in the understanding of the causes and consequences of centrosome abnormalities and their connection to cancers. Centrosome abnormalities can drive the initiation and progression of cancers in multiple ways. For example, they can generate chromosome instability through abnormal mitosis, accelerating cancer genome evolution. Remarkably, it is becoming clear that the mechanisms by which centrosome abnormalities promote several steps of tumorigenesis are far beyond what Boveri had initially envisioned. We highlight various cancer-promoting mechanisms exerted by cells with centrosome abnormalities and how these cells possessing oncogenic potential can be monitored.

컨테이너 임시교사의 품질개선방안 (Measures for Improving the Quality of Temporary Container Classrooms)

  • 유병재;방홍순;이종성;김옥규
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2021년도 봄 학술논문 발표대회
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    • pp.38-39
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    • 2021
  • The use of temporary container classrooms has increased in recent years due to the development of the construction industry and renovation or rehabilitation of schools. Therefore, various problems, such as errors during assembling, design and insulation issues, and noise problems, have surfaced during the construction of temporary container classrooms. This study analyzes the causes of assembly errors during the manufacturing and installation processes to improve the quality of temporary container classrooms. Assembly errors are caused by non-level planes and inaccurate cutting during the manufacturing process. In the installation process, poor leveling is a major factor that causes errors during the assembly of temporary container classrooms. These causes result in uneven horizontal or vertical planes and uneven height. To solve these problems, quality improvement measures, such as pin connection, jig, joint coupling, and surface plates are proposed in this study.

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E-resources usage among Polytechnic students in Southwest Nigeria: evidence from Federal Polytechnic, Ede and The Polytechnic, Ibadan Nigeria

  • Alasa, Sekinat Abiodun;Quadri, Ganiyu Oluwaseyi
    • International Journal of Knowledge Content Development & Technology
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    • 제12권1호
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    • pp.49-65
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    • 2022
  • This study examined e-resources usage among polytechnic students in Southwest Nigeria. A descriptive research design was adopted for this study and the population consisted of polytechnic students from The Polytechnic, Ibadan and Federal Polytechnic, Ede. There were 9671 students from both polytechnics. A multi-stage sampling technique was employed with a sample fraction of 5% was drawn from the total number of students in each faculty amounting to 381. A structured questionnaire was the major instrument used for data collection and the questionnaire was pre-tested using Cronbach-alpha to determine the reliability co-efficient. Data obtained was analyzed using SPSS. The study found that the students from both polytechnics are aware of the e-resources and that the e-resources were mainly used for research, class assignment and to update knowledge. The problem such as epileptic power supply, poor internet connection and so on was identified. The study concluded that polytechnic students could benefit immensely from the enormous usage of e-resources particularly for teaching, learning and research. Based on the findings, recommendations were made.

Creation of High-Quality Abstractions in Software Engineering

  • Alexey Razumowsky
    • International Journal of Computer Science & Network Security
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    • 제23권7호
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    • pp.193-201
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    • 2023
  • Abstraction is the cornerstone of ideal software engineering (SWE). This paper discusses a problem of forming reasonable generalizations, representations and descriptions in various software development processes through the prism of poor-quality (rash, unconsidered, uncertain and harmful) abstractions. To do this, emphasis is made on an induced strategic connection between the required abstraction and its compact specific formulation based on existing research and the author's introspective experience. A software aim point and characteristic preservation of the solution integrity is the subject of the best formulation and a program module or code associated with it. Moreover, a personal attitude expressed by personal interest, motivation and creativity, is proclaimed to be a fundamental factor in successful software development.

폴리우레탄 구조 변화에 따른 은 입자의 분산 특성 (Dispersity of Silver Particles in Polyurethane Matrix: Effect of Polyurethane Chemical Structure)

  • 임현구;이혁수;김주헌
    • 폴리머
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    • 제31권6호
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    • pp.543-549
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    • 2007
  • 폴리우레탄의 우수한 기계적 물성에 전기 전도성을 가질 수 있도록 은 입자와의 복합체를 제조하였다. 균일하고 우수한 물성을 나타내기 위해서는 고른 분산성이 중요하게 되는데 폴리우레탄의 hard segment와 soft segment를 바꿔가며 가장 열적 안정성이 뛰어나고 은 입자를 균일하게 분산시킬 수 있는 폴리우레탄의 구조를 파악하였다. 열적 안정성은 방향족 증가와 사슬의 hard segment 비율 증가에 따라 높아짐을 알 수 있었고 분산성에서는 hard segment의 방향족이 포함된 것이 지방족보다 우수한 분산성을 가졌다. 또한 soft segment에 따라서는 낮은 분자량에서 사슬의 motility로 인해 좋은 분산성을 나타내었다. 하지만 전기 전도성에서는 고른 분산성보다도 입자간의 inter-connection을 이룰 수 있는 형태가 가장 낮은 저항값을 나타내었으며. NDI와 낮은 분자량의 PEG로 이루처진 복합체가 가장 좋은 물성을 나타내었다.