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An Experimental Study of Polypropylene Fiber for the Prevention of Explosive Spalling of Tunnel Concrete Lining (터널 콘크리트 라이닝 폭열 방지를 위한 폴리프로필렌 섬유 혼입율 분석 연구)

  • Kim, Nag Young;Shim, Jae Won;Shim, Jong Sung;Won, Jong Phil
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.7 no.4
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    • pp.323-333
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    • 2005
  • Recently the fire is happening at the tunnel and underground - structure internationally. We are socially the economy the actual circumstances which serious loss is happening due to an fire occurrence when fire happened which is closed like tunnel and underground - structure, the collapse from the burglar degradation of strength of tunnel concrete lining and human life damage happen. It causes big problem while the long time disconnects a traffic network. While the fire happened in this research at the tunnel, the paper construct a basis data to deduce the specification regulation about stability of tunnel concrete lining. In this paper, the experiment was carried out for the prevention of explosive spalling of tunnel to use a reinforced Polypropylene concrete which mixes a Polypropylene which are known for the thing by being efficient at a protect of explosive spalling of the concrete. According to the firproof test result of reinforced Polypropylene admixture mortar, Polypropylene admixture of prevention of explosive spalling analyzed 0.2%-0.25%.

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Efficient countermeasures against e-terrorism (e-테러리즘의 효율적 통제방안)

  • Lee, Yoon-Ho;Kim, Dae-Kwon
    • Korean Security Journal
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    • no.20
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    • pp.271-289
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    • 2009
  • In e-terrorism, terrorists use cyber spaces including the internet in order to strike terror into the heart of a nation. It is revealed that recently happening terror cases use cyber spaces as a strategic tool. This research aims to investigate efficient countermeasures against various types of terror attacks made by terrorists and their cyber networking, in order to contribute to the prevention of terrors from a modern standpoint. Based on the results of the investigation, relevant problems are suggested such that terrors are not cases happening in a specific country only because they take place in cyber spaces, that hacking incidents frequently happen in Korea which is used as a footstool by foreign hackers, and that Korea has poor professional security manpower and foundational facilities in comparison with other advanced countries. Answers to the problems include cultivating cyber information manpower to cope with e-terrorism, making an appropriate budget, setting up networks to integrate and systematize anti-e-terrorism organizations, and intensifying the collection of information of cyber attacks and the analysis of the information.

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Analysis Study on the Damage of Crack Happening with the Bending at CFRP Plate due to Stacking Angle (적층각도에 따른 CFRP 평판에서의 굽힘으로 발생한 크랙 파손에 관한 해석적 연구)

  • Hwang, Gue-wan;Cho, Jae-ung
    • Journal of the Korea Convergence Society
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    • v.8 no.3
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    • pp.185-190
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    • 2017
  • This study investigates the bending stress, shear stress and deformation energy happening at the inner fiber structure when the bending moment is applied to he specimen with flat shape composed of carbon fiber. As CFRP is composed of innumerable fibers with multi-axes, the stress under bending condition can be effectively distributed. Theses stresses is shown to increase again at the starting point as this angle of $60^{\circ}$. Therefore, the condition at the stacking angle of $60^{\circ}$ is seen to become most adequate under the state where the bending stress happens. On the basis of this study result, the damage property by the bending at the plate due to stacking angle was examined through the analytic approach. it is thought that this study can be devoted to the safe design for damage prevention and durabilty improvement. Also, the esthetic sense can be shown as the designed factor of shape with flat plate is grafted onto the convergence technique.

Middle School Students' Perceptions of Science Classroom Learning Environments (중학생의 과학 교실 학습 환경에 대한 인식)

  • Hong, Mi-Young;Kang, Nam-Hwa;Kim, Joo-Ah
    • Journal of The Korean Association For Science Education
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    • v.30 no.1
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    • pp.68-79
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    • 2010
  • This study utilized the What Is Happening In this Class (WIHIC) questionnaire to examine students' perceptions of their science learning environment. Data was collected from 587 middle school students in seven coeducation schools in Seoul. Higher mean scores occurred on the scales of Student cohesiveness, Task orientation, Cooperation and Equity in the WIHIC, whereas lower mean scores occurred on Teacher support, Involvement and Investigation. The effects of gender on students' perceptions of their science learning environment were not statistically significant overall, but girls perceived Student cohesiveness and Cooperation more positively than boys. Correlations between the WIHIC scales of the low-level group that perceived their learning environments negatively (10 percentiles) and the high-level group that perceived their learning environments positively (90 percentiles) were computed. Teacher support, Involvement, Task Orientation and Investigation were highly correlated with each other in the low-level group, whereas only Teacher support and Equity were correlated in the high group. Educational implications were discussed.

Development of Safe Navigation Contents for Aging Seafarer in Tug-barge Transportation (고령 예부선 운항자를 위한 안전운항 교육 콘텐츠의 개발)

  • Kim, Hong-Tae;Chang, Hea-Jung;Kim, Hye-Jin
    • Journal of Navigation and Port Research
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    • v.35 no.5
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    • pp.351-358
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    • 2011
  • Recently, tugs and barges have become larger in size and increased in number. Also, most of tugs and barges are more than ten-years old. Total number of marine accident has been decreased, whereas that of accidental happening in tug-barge transportation has not been decreased. The statistics of marine accidents in 2010 shows that tug-barge accidents increased rapidly compared with those of 2009. The cause of accidental happening in tug-barge transportation is a quality of tug-barge operator the labour serious shortage of crew. This study is to give or suggest the various educational contents considering old age of crew and navigational environment for safe navigation in tug-barge transportation.

The condition and the analysis of the problems of the Japanese - The change of the Korean geriatric security law - (일본 유료 노인홈의 현황과 그 문제점 분석 - 우리나라 노인 복지법 개정에 즈음하여 -)

  • 신경주
    • Proceeding of Spring/Autumn Annual Conference of KHA
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    • 1993.09a
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    • pp.13-20
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    • 1993
  • In Korea, the elderly support has been accomplished by the families in the extended family system with the influence of the transmigration and the confucianism thought. But in Korea the drastic changes of society such as, the growth of the elderly pollution, the urbanization, the decrease of the birth rate, the increase of the working women, the growth of the nuclear families, etc., make the family difficult to take care of the elderly. Therefore, some people insist on the construction of the elderly home as the way to solve the elderly problems and some of corporations including profit-organizations are ready to participate the construction of the elderly home. They force the change of the current social security law because it is impossible to carry out the plans uncer the law. At this point, the conditions of the elderly home in Japan which is geographically close to Korea and has facillicated the elderly home business were examined at the consumer perspectives. The purpose of this study were to consider the possible problems in the elderly home and to prevent from happening another elderly problems in the future.

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Analysis of Influence for High Frequency voltage Accelerated Aging of XLPE Cable (고주파 전압이 XLPE cable의 가속열화에 미치는 영향 분석)

  • Kim, We-Young;Hu, Jong-Chul;Yun, Dae-Hyuk;Park, Tae-Gone
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.1670-1672
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    • 2004
  • XLPE compound have used for insulation of 22.9kV power cable. XLPE insulation is aged for use long time in distribution line. The cause of aging is water tree is happening and growth. Accelerated water tree test method are Accelerated volatge aging method and high frequency aging method. In this paper, high frequency accelerated water tree was performed. And the result was analysed AC breakdown voltage and size and number of water trees.

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Efficient Pre-Bond Testing of TSV Defects Based on IEEE std. 1500 Wrapper Cells

  • Jung, Jihun;Ansari, Muhammad Adil;Kim, Dooyoung;Park, Sungju
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.16 no.2
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    • pp.226-235
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    • 2016
  • The yield of 3D stacked IC manufacturing improves with the pre-bond integrity testing of through silicon vias (TSVs). In this paper, an efficient pre-bond test method is presented based on IEEE std. 1500, which can precisely diagnose any happening of TSV defects. The IEEE std. 1500 wrapper cells are augmented for the proposed method. The pre-bond TSV test can be performed by adjusting the driving strength of TSV drivers and the test clock frequency. The experimental results show the advantages of the proposed approach.

A Study on the Big Data Analysis System for Searching of the Flooded Road Areas (도로 침수영역의 탐색을 위한 빅데이터 분석 시스템 연구)

  • Song, Youngmi;Kim, Chang Soo
    • Journal of Korea Multimedia Society
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    • v.18 no.8
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    • pp.925-934
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    • 2015
  • The frequency of natural disasters because of global warming is gradually increasing, risks of flooding due to typhoon and torrential rain have also increased. Among these causes, the roads are flooded by suddenly torrential rain, and then vehicle and personal injury are happening. In this respect, because of the possibility that immersion of a road may occur in a second, it is necessary to study the rapid data collection and quick response system. Our research proposes a big data analysis system based on the collected information and a variety of system information collection methods for searching flooded road areas by torrential rains. The data related flooded roads are utilized the SNS data, meteorological data and the road link data, etc. And the big data analysis system is implemented the distributed processing system based on the Hadoop platform.

On the Mater and Form of Landscape -by the case of the Grotto Sokgulam- (경관에 개재된 내용과 형식의 해석 -석굴암 조영을 통하여 본 석 굴형식과 신라의 동향문화성을 중심으로-)

  • 정기호
    • Journal of the Korean Institute of Landscape Architecture
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    • v.19 no.2
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    • pp.23-31
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    • 1991
  • In this paper, based on the thought of the place, I tried to define the meaning of th place and interprete its landscape. The landscape of the mt. Toham with its Grotto-temple "Sokgulam" is the major object of it. The "matter and form" of the Sokgulam realizes the archetypal meaning of the grotto, birth or place of the birth, in a concrete picture. The aesthetics of the Sokgulam, the mater and form in the work of arts, comes out light harmonious with the elements: "grotto", the new foreign element of the architectural style and "orientation", the old domestic one of the Shilla that presented itself at the Chomsongdae, a kind of observatory. The interrelation of the old and new elements in work of the Sokgulam shows us also a thought as an opinion of the transference to say: the matter of the traditional subject, "grotto" and the form makes the abstract matter concretely in sight, by receiving the natural happening of the sunrise at the winter solstice.

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