• Title/Summary/Keyword: a confined area

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Nonlinear Lateral Behavior and Cross-Sectional Stress Distribution of Concrete Rocking Columns (콘크리트 회전형 기둥의 비선형 횡방향 거동 및 단면응력 분포 분석)

  • Roh, Hwa-Sung;Hwang, Woong-Ik;Lee, Hu-Seok;Lee, Jong-Seh
    • Journal of the Korea Concrete Institute
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    • v.24 no.3
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    • pp.285-292
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    • 2012
  • Fixed connection is generally used for beam and column connections of concrete structures, but significant damages at the connection due to severe earthquakes have been reported. In order to reduce damages of the connection and improve seismic performance of the connection, several innovative connections have been suggested. One newly proposed connection type allows a rotation of the connection for applications in rotating or rocking beams, columns, and shear walls. Such structural elements would provide a nonlinear lateral force-displacement response since their contact depth developed during rotation is gradually reduced and the stress across the sections of the elements is non-linearly distributed around a contact area, which is called an elastic hinge region in the present study. The purpose of the present study is to define the elastic hinge region or length for the rocking columns, through investigating the cross-sectional stress distribution during their lateral behavior. Performing a finite element analysis (FEA), several parameters are considered including axial load levels (5% and 10% of nominal strength), different boundary conditions (confined-ends and cantilever types), and slenderness ratios (length/depth = 5, 7, 10). The FEA results showed that the elastic hinge length does not directly depend on the parameters considered, but it is governed by a contact depth only. The elastic hinge length started to develop after an opening state and increased non-linearly until a rocking point(pre-rocking). However, the length did not increase any more after the rocking point (post-rocking) and remained as a constant value. Half space model predicting the elastic hinge length is adapted and the results are compared with the numerical results.

A Study for the Factors that Affect the Library Services for the Visually Handicapped (시각장애인을 위한 도서관의 구성요소분석)

  • Jeon Jae-Bong
    • Journal of the Korean Society for Library and Information Science
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    • v.24
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    • pp.139-169
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    • 1993
  • The major purpose of this study is to scrutinize and analyze various factors in numerous aspects of two different library systems for the visually handicapped, namely braille library and a special section for the visually handicapped in the public library system. The analyses may provide theoretical and conceptual framework on which strategies to enhance services for the visually handicapped is to be developed. More specifically, this study seeks (1) to examine a linkage between the degree of maintenance of staffs, collections, and equipment and the level of satisfactions of librarians and (2) to come up with more effective mechanisms of welfare services for the visually handicapped in each library system. This research is qualitative-descriptive and uses interview method. Fourteen libraries throughout the nation (4 public libraries with a reading room for the visually handicapped and 8 braille libraries) which had been in operation more than one year were selected as subjects for the research. Findings and results of the analyses are summarized as follows : 1. There seems to be general consensus that each of public and braille library has significant but, to a certain extent, different roles to play in order to enhance library services for the visually handicapped. Recruitment of qualified librarians, increase of the volume of collection, and enlargement of reading room space are noted as immediate concerns for the former. For the latter, it was suggested that increase of the number of staff for publishing, securing more equipments for pulication in braille, and wider scope as well as more variety of publications are the pressing problems at hand. 2. Both public and braille library employ one librarian for the visually handicapped who is required to have educational background in library science and special education. In addition, one must have competence in reading braille types. 3. Majority of reading rooms in those libraries is so small in physical aspect that size and number of seats are 66m2 and 15 seats respectively because circulation services are mainly in use due to the problem of inaccessibility which is commonly suffered by the visually handicapped. 4. Library services for the visually handicapped are heavily concentrated upon the large urban area. In fact, most of braille libraries are located in Seoul whereas a reading room for the visually handicapped in the public library system are exclusively placed in the large cities such as Inchon, Taejon, and Taegu. 5. All of the public library is neither equipped with necessary facilities to publish in braille nor secured supporting instruments which may facilitate library use for the visually handicapped. On the contrary, most of braille libraries are equipped with arrangements to publish in braille despite supporting devices are gererally lacking. 6. Consequently, provision of services In the public library is largely confined to reading and circulation of materials purchased from braille libraries while major task of braille libraries centers around publication and distributions of the reading materials in braille.

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An Analysis of Sexual Health Education for Korean Adolescents (청소년대상 영상매체 성교육자료분석 -비디오를 중심으로-)

  • Lee, Koang-Ok;Yang, Soon-Ok;Im, Mi-Lim
    • Research in Community and Public Health Nursing
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    • v.9 no.2
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    • pp.441-457
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    • 1998
  • The purpose of this study is to provide fundamental information for the development of new sex education image media through the analysis of those tools produced by Planned Parenthood Federation of Korea. Twenty three video tapes related to the sex education were analysed. The data were sampled on the basis of the sex education instructions for primary and secondary schools published by the Seoul Office of Education in 1996 and the list of sex education information composed by the Planned Parenthood Federation of Korea with the following requirements. 1) The education materials are oriented to the middle and high school students as well a juveniles and are being used in public health centers and schools. 2) The education materials are not confined to the single subject such as AIDS or contraception. Because this study is focused on the analysis of image media, an analysis method widely and effectively used in public media study was chosen. The frequency analysis and percentage treatment were done by an SAS program. The results of the study are as follows : 1. An analysis of the material structure type showed that the frequency of the following subjects in 15 video tapes, composed as drama and cartoon, had this decreasing orde : sex behavior, sex relation ships, sex health, human development, personal technique, and society and culture. 2. The eight tapes of explanation and counseling showed a different sequence from that of the drama and cartoon material, primarily treating human development with 5419 seconds (47.9%) of type. The following were also considered in decreasing order: at 2000seconds (17.6%) sex behavior, at 1366 seconds (12.1%) sex health, at 1240 seconds (11.0%) society and culture, at 667 seconds (6.0%) relation ships, and at 611 seconds (5.4%) personal technique. 3. In a thematic analysis those education materials dealing with human development show this frequency sequence: anatomic physiology, reproduction, and adolescence. In relation, ships the sequence is dates, love, marriage and vows, and family. For personal technique, it is expressed as asking for help, and an empnasis on moral values. For sex behavior, they focus on abstinence, the co-responsibility of sex behavior, the sexual response of the human, and sexual nightmares. For the sex health area, the focus is contraception with abortion and reproductive health following that. In society and culture diversity is considered. 4. An analysis of the differences in production and content between 1980s and 1990s was also done. For materials produced in the 1980s the frequency of the subjects follows this order: sex behavior, human development, relation ships, sex health, personal technique, and society and culture with sub subjects such as abstinence, dating, adolescence, anatomic physiology, reproduction, calls for help, and the sexual response of a human being. For materials produced in the 1990s, highest frequency was sex behavior, the same as the 1980s. The rest of the material follows this decreasing order: relationships, human development, sex health, society and culture, and personal technique with sub subjects such as dating, co-resposibility in sex behavior, abstinence, and love frequently considered.

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Research on the Structure of 4 Panel Comic Strips and Rhetoric Expression for the Education of Comic Contents: with of Kyunghyangsinmoon (만화콘텐츠 교육을 위한 네칸만화 구조와 수사법 연구: 경향신문 <장도리>를 중심으로)

  • Park, Keong-Cheol
    • Cartoon and Animation Studies
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    • s.19
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    • pp.17-35
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    • 2010
  • We can say that there are several majors in the course of cartoon education of college; cartoon, manpyung, 4 panel comic strips, editorial cartoon, webtoon and so on. Among them, this study starts with concrete question; "How can we encourage students to understand 4 panel comic strips better in the educational course of 4 panel comic strips?" 4 panel comic strips divided into two groups, depending on the materials. The first is daily cartoon which depicts the emotion in daily life. The second is editorial cartoon which deals with the problems of society in the ironical and witty way. Judging from my own thoughts that it would be better in the understanding and analysis of structures to take editorial cartoon in which materials are confined to social problems, this study treats rhetoric expression and structures of 4 panel comic strips. Introduction, development, turn and conclusion of "Jangdori" on Kyunghyangsinmoon are good materials for this study. So, "Jangdori" is in the center of this study. The objective of this study is to provide knowledge in creating 4 panel comic strips with the understanding the area of 4 panel comic strips through the analysis of the rhetoric expression and structures of this field. Even though this study has a limit, no access to daily 4 panel comic strips, I hope that this study would be a little help in any places in which the education of 4 panel comic strips is needed as a part of a course of cartoon in college.

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Biodegradation of Polynuclear Aromatic Hydrocarbons in soil using microorganisms under anaerobic conditions (혐기성 미생물에 의한 토양내 다핵성방향족화합물의 생물학적 분해)

  • An, Ik-Seong
    • 한국생물공학회:학술대회논문집
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    • 2000.04a
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    • pp.89-91
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    • 2000
  • Polynuclear aromatic hydrocarbon (PAH) compounds are highly carcinogenic chemicals and common groundwater contaminants that are observed to persist in soils. The adherence and slow release of PAHs in soil is an obstacle to remediation and complicates the assessment of cleanup standards and risks. Biological degradation of PAHs in soil has been an area of active research because biological treatment may be less costly than conventional pumping technologies or excavation and thermal treatment. Biological degradation also offers the advantage to transform PAHs into non-toxic products such as biomass and carbon dioxide. Ample evidence exists for aerobic biodegradation of PAHs and many bacteria capable of degrading PAHs have been isolated and characterized. However, the microbial degradation of PAHs in sediments is impaired due to the anaerobic conditions that result from the typically high oxygen demand of the organic material present in the soil, the low solubility of oxygen in water, and the slow mass transfer of oxygen from overlying water to the soil environment. For these reasons, anaerobic microbial degradation technologies could help alleviate sediment PAH contamination and offer significant advantages for cost-efficient in-situ treatment. But very little is known about the potential for anaerobic degradation of PAHs in field soils. The objectives of this research were to assess: (1) the potential for biodegradation of PAH in field aged soils under denitrification conditions, (2) to assess the potential for biodegradation of naphthalene in soil microcosms under denitrifying conditions, and (3) to assess for the existence of microorganisms in field sediments capable of degrading naphthalene via denitrification. Two kinds of soils were used in this research: Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS). Results presented in this seminar indicate possible degradation of PAHs in soil under denitrifying conditions. During the two months of anaerobic degradation, total PAH removal was modest probably due to both the low availability of the PAHs and competition with other more easily degradable sources of carbon in the sediments. For both Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS), PAH reduction was confined to 3- and 4-ring PAHs. Comparing PAH reductions during two months of aerobic and anaerobic biotreatment of MHS, it was found that extent of PAHreduction for anaerobic treatment was compatible with that for aerobic treatment. Interestingly, removal of PAHs from sediment particle classes (by size and density) followed similar trends for aerobic and anaerobic treatment of MHS. The majority of the PAHs removed during biotreatment came from the clay/silt fraction. In an earlier study it was shown that PAHs associated with the clay/silt fraction in MHS were more available than PAHs associated with coal-derived fraction. Therefore, although total PAH reductions were small, the removal of PAHs from the more easily available sediment fraction (clay/silt) may result in a significant environmental benefit owing to a reduction in total PAH bioavailability. By using naphthalene as a model PAH compound, biodegradation of naphthalene under denitrifying condition was assessed in microcosms containing MHS. Naphthalene spiked into MHS was degraded below detection limit within 20 days with the accompanying reduction of nitrate. With repeated addition of naphthalene and nitrate, naphthalene degradation under nitrate reducing conditions was stable over one month. Nitrite, one of the intermediates of denitrification was detected during the incubation. Also the denitrification activity of the enrichment culture from MHS slurries was verified by monitoring the production of nitrogen gas in solid fluorescence denitrification medium. Microorganisms capable of degrading naphthalene via denitrification were isolated from this enrichment culture.

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Development of Emergency Restoration Scenarios for Railway Accident using Analytic Network Process (네트워크분석적 의사결정기법을 이용한 철도사고 임시복구시나리오 개발)

  • Sung, Deok-Yong;Park, Yong-Gul
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.5D
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    • pp.727-737
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    • 2011
  • The emergency restoration scenarios for efficient railway accident management and restoration were developed. The emergency restoration procedures defined by the worst case of emergency restoration and the important events was proposed based on questionnaires from specialists and the result of survey. Via these studies, the railway accident in the tunnel could be the worst case among all railway accident types. Therefore, educations for a restoration team in confined area condition should be planned and performed to recover the worst case accident. In order for the emergency restoration, when a railway accident is occurred, the restoration should be performed in orders of handing collapse of facilities, burying track, and derailment of vehicle in tunnel based on the statistical analysis. The result of priorities were established by the period of restoration. The standard operation system for efficient railway accident management was developed by synthesizing the worst case for rapid emergency restoration, and important events for the standard operation procedures according to each emergency restoration type. Through this study, the restoration operation system of railway accident are recommended. This paper suggests to develop emergency restoration scenarios for the efficient railway accident management and recovery system. The study results will contribute not only for insuring punctuality, but also for minimizing delays from accidents. Therefore, emergency restoration scenarios will play a major role in the SOP for the damage limitation and the prevention of accident spread.

Electrochemical Template Synthesis of Conducting Polymer Microstructures at Addressed Positions (템플레이트의 국소 위치에 형성된 전도성 고분자 미세구조물의 전기화학 합성)

  • Lee Seung Hyoun;Suh Su-Jeong;Yun Geum-Hee;Son Yongkeun
    • Journal of the Korean Electrochemical Society
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    • v.7 no.2
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    • pp.100-107
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    • 2004
  • The nano or micro sized structures of conducting polymer had been prepared by synthesizing the desired polymer within the pores of template of nano or micro porous membrane filter. In this study, we had tried to fabricate conducting polymer microstructures on an electrode by using electrochemical deposition adopting template synthesis. Our attention was focused on two different things, attaching template on the electrode and fabricating microstructures only at limited areas of the electrode. A conducting polymer, PEDiTT (poly 3,4-ethylenedithi-athiophene) solution was blended with PVA(polyvinyl alcohol) solution and used as an conducting adhesive. After attaching template membrane, the electrode were immersed in 0.5M pyrrole in 0.1M KCI solution, and electrochemical polymerization was performed. The growth process of the microstructures studied by SEM. The electrochemical fabrication of conducting polymer was performed by using two-electrode system. A large working electrode and a micro scale disc electrode were used for the confined area synthesis. Polymerization potential was 4V in an electrolytic solution made of KCI in deionized water. The optimum polymerization conditions were, i.e. (4V/100sec) for $250{\mu}m$ electrode and (6V/30 sec) for $10{\mu}m$ electrode.

The Stability Analysis of Near Parallel Tunnels Pillar at Multi-layered Soil with Shallow Depth by Numerical Analysis (수치해석에 의한 저토피 다층지반에서 근접 병설터널 필라의 안정성 분석)

  • Lim, Hyungmin;Son, Kwangrok
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.1
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    • pp.53-62
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    • 2014
  • In Korea, in general, separation distance between existing parallel tunnels was set at two to five times as distant as the diameter of the tunnels according to ground conditions. Recently, however, actual applicability of closely spaced parallel tunnels whose distance between tunnel centers was shorter than the diameter has increased due to environmental damages resulting from massive cutting, restriction in purchase of required land, and maintenance of linear continuity. In particular, when the pillar width of tunnel decreases, the safety of pillars affects behaviors of the tunnel and therefore the need for diverse relevant studies has emerged. However, research so far has been largely confined to analysis of behavior characteristics of pillars, or parameters affecting design, and actually applicable and quantitative data have not been presented. Accordingly, in order to present a stability evaluation method which may maximally reflect construction conditions of spots, this study reflected topographical and stratigraphic characteristics of the portal part with the highest closeness between the tunnels, simulated multi-layer conditions with rock mass and complete weathering, and assessed the degree of effect the stability of pillars had on the entire tunnels through numerical analysis according to changes in pillar width by ground strength. This study also presented composite analysis result on ground surface settlement rates, interference volume rates, and average strength to stress and a formula, which may be applicable to actual work, to evaluate safety rates of closely spaced parallel tunnel pillars and minimum pillar width by ground strength based on failure criteria by Hoek-Brown (1980).

Seismic Response Evaluation of Composite Steel-Concrete Box Girder Bridge according to Aging Effect of Piers (교각의 노후도 영향에 따른 강합성 상자형 거더교의 지진응답 평가)

  • Shin, Soobong;Hong, Ji-Yeong;Moon, Jiho;Song, Jong-Keol
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.33 no.5
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    • pp.319-329
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    • 2020
  • Among the bridges used in Korea, those that are more than 30 years old account for approximately 11% of the total bridges. Therefore, developing a seismic performance-evaluation method is necessary by considering the bridge age. Three composite steel-concrete box girder bridges with port, elastic-rubber, and lead-rubber bearings were selected, and a structural analysis model was developed using the OpenSEESs program. In this study, pier aging was reflected by the reduction in the area of the longitudinal and transverse rebars. Four conditions of 5%, 10%, 25%, and 50% in the degree of pier aging were used. As input earthquakes, 40 near-fault and far-field earthquakes were used, and the maximum displacement and maximum shear-force responses of the piers were obtained and compared. The result shows that as the aging degree increases, the pier strength decreases. Therefore, the pier displacement response increases. To analyze the effects of displacement response and shear resistance, displacement ratio Dratio and shear-force ratio Fratio were evaluated. The older the sample bridge is, the greater is the tendency of Dratio to increase and the smaller is the tendency of Fratio to decrease.

A Study on Experience of Parents Who Moved to Rural Village for Their Children's Education (전원마을 이주 학부모의 자녀교육 경험에 대한 연구)

  • Shin, Meesook;Kil, Yangsook
    • The Journal of the Convergence on Culture Technology
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    • v.6 no.1
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    • pp.155-162
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    • 2020
  • We extracted the meaning of educational experience of the parents who moved to rural village for their children's education. While moving to the cities for the childen's education is general trend, moving to the rural village for the children's education is peculiar phenomenon. For the study, in-depth interviews were conducted with six parents who moved to rural village, and the statements were analyzed by the phenomenological analysis method of Colaizzi. As a result, thirty themes, eight theme clusters, and three meaning categories were extracted. Three categories which characterize the experience of parents who moved to rural village for their children are 'longing for nature-friendly life in rural area', 'positive experience of communication and empathy with neighbors', and 'children's happiness-centered education'. Eight theme clusters are 'dislike confined environment of an apartment', 'positive experience of childhood in the countryside', 'value direct and indirect experiences of variety', 'free and stimulating environment of countryside', 'experience of communicating and empathizing with neighbors','regret private education caused by parents' greed', 'value child centered education', 'yearn for the self-directed learning around character and art-physical abilities'. Based on the result, implications were discussed and follow-up studies were suggested.