• Journal of Korean Tunnelling and Underground Space Association
• /
• v.10 no.2
• /
• pp.193-205
• /
• 2008

The construction of underground structures such as oil and food storage caverns are recently increasing in our country. The stability of those underground caverns are greatly influenced by their shape and size. In this study therefore, the effect that the shape of an underground cavern have on its stability were analyzed in terms of safety factor. To this end, caverns with 5 different shapes were investigated and sensitivity analyses were performed based on rock class, overburden, and lateral earth pressure coefficient. The proper amount of shotcrete and rockbolt as supports of a cavern was also assumed based on the shape and site of the cavern and rock conditions. This study is expected to be helpful in designing and evaluating the stability of caverns in future.

• Geotechnical Engineering
• /
• v.14 no.1
• /
• pp.93-108
• /
• 1998

In this study, the analytic solutions and numerical methods were used to estimate the shape and size effects on the stability of underground openings. The stability of underground openings was evaluated by scrutinizing the effects of the rock mass quality, the state of in-situ stresses and the lateral earth pressure coefficient on the displacement, the stress concentration and the plastic region developed in the vicinity of the openings. The analytic solutions have shown that the stress concentration factor is inversely proportional to the radius of curvature of openings. Through parametric study on the various shapes and sizes of underground openings the characteristics of the controlling factors concerned with the stability were analyzed. Then, the study was extended to the horseshoe-shaped openings commonly used for under ground storage. Through the extended study the effects of the stress ratio and the height-towidth ratio of openings on the maximum displacement and plastic region developed around the openings were estimated. The results have shorn that the height-to-width ratio of domestic storage caverns can be increased economically without stability problem, as far as the lateral earth pressure coefficient is appropriate.

• Journal of the Korean Society for information Management
• /
• v.31 no.3
• /
• pp.153-179
• /
• 2014

This study explores the characteristics of centrality measures for analyzing researchers' impact and structural positions in research collaboration networks. We investigate four binary network centrality measures (degree centrality, closeness centrality, betweenness centrality, and PageRank), and seven existing weighted network centrality measures (triangle betweenness centrality, mean association, weighted PageRank, collaboration h-index, collaboration hs-index, complex degree centrality, and c-index) for research collaboration networks. And we propose SSR, which is a new weighted centrality measure for collaboration networks. Using research collaboration data from three different research domains including architecture, library and information science, and marketing, the above twelve centrality measures are calculated and compared each other. Results indicate that the weighted network centrality measures are needed to consider collaboration strength as well as collaboration range in research collaboration networks. We also recommend that when considering both collaboration strength and range, it is appropriate to apply triangle betweenness centrality and SSR to investigate global centrality and local centrality in collaboration networks.

• Korean journal of communication and information
• /
• v.81
• /
• pp.40-74
• /
• 2017

Drawn upon the analysis of Seoul community media, this study make six points. The generation of community is not essentially determined but has singularity and differences. Historical context, social conditionality, cultural orientation, and the subjects' will and anticipation bring out certain forms of community. Various power relations and desires are engaged in the formation of community. The process of the construction of community is necessarily and simultaneously mediated with collective acts of communication and sharing. Community is not so much cultivated within society as articulated with precariousness, negativity and limit. Community is able to create its own cultural sensibility and language to express it. Thereby community is a dynamics between articulation and disarticulation, convergency and divergency, similitude and difference living in our actual society.

• Tunnel and Underground Space
• /
• v.15 no.5 s.58
• /
• pp.369-377
• /
• 2005

The stability of underground openings is a major concern for the safety and productivity of mining operations. Rock mass classification methods provide the basis of many empirical design methods as well as a basis for numerical analysis. Of the many factors which influence the stability of openings, the span of the opening for a given rock mass condition provides an important parameter of design. In this paper, the critical span curves proposed by Lang, the Mathews stability graph method and the modified critical span curve suggested by the authors have been assessed. The modified critical span curve was proposed by using Mathews stability graph method. The modified critical span curve by the author have been used to assess the stability of underground openings in several limestone mines.

• Korea journal of population studies
• /
• v.27 no.2
• /
• pp.61-89
• /
• 2004

1990년 이후 중국 조선족 사회는 급격한 변화의 소용돌이에 휩싸여있다. 그 핵심에는 조선족 공동체의 총체적인 재구조화가 자리하고 있다. 조선족 집거지로부터 대규모의 이촌 현상이 나타나고 있으며 동북3성에 집중되어 있던 조선족은 전 중국으로 흩어지고 있다. 이러한 조선족의 이동은 조선족 공동체의 해체현상으로 이해되는 경향이 있다. 이 연구는 바로 인구이동이 조선족 사회와 공동체에 어떠한 영향을 주는지에 대한 물음에서 출발한다. 그리고 영향은 이동의 기원지인 농촌과 다양한 목표지의 현황과 조건, 이를 둘러싼 사회경제적 상황을 중심으로 다룬다. 이를 위해 사례연구를 실시하였으며, 필요한 자료는 선택된 마을의 방문과 현지에서의 심층면접을 통해 수집하였다. 연구의 결과는 조선족의 대규모, 원거리 이동이 조선족 공동체의 해체를 뜻하는 것은 아니라는 점을 명백히 보여준다. 인구유출로 도시 또는 조선족 중심지에서 떨어진 농촌 마을에서 공동체의 해체는 빠른 속도로 이루어진다. 그러나 조선족은 새로운 목표지에서는 새로운 유형의 집중현상을 보인다. 한마디로 조선족의 이동은 조선족 사회의 도시화의 경향과 함께, 보다 넓은 지역으로의 공동체의 분산과 공동체내에서의 높은 민족 집중성을 특징으로 전개되고 있다. 또한 조선족 도시 공동체는 거주지역의 격리보다는 민족성을 기초로 한 문화적 정체성에 대한 강조를 특징으로 한다.

• Informatization Policy
• /
• v.18 no.2
• /
• pp.23-48
• /
• 2011

This empirical study is on the factors that influence college students'intention of using online communities by focusing on the social influence, online community identification and attitude toward using online community, and the perceived usefulness. The results of this study are as follows. First, the most popular online community site is Cyworld, and was found to provide additional services like cafes, blogs, facebook, etc. Second, the social influence in the proposed model has been classified as a subjective norm, perceived usefulness of social influence has been identified as a significant variable, and online community identification of subjective norm was significant. Third, the model configuration in a path relationship between the variables, the indirect effect of online community identification and perceived usefulness affect usage intention of online communities was larger than a direct effect. Therefore, in order to increase the usage intention of online communities, online community identification and perceived usefulness, as well as by attitude toward using online community need to be considered as ways to improve were identified.

• Proceedings of the Korean Society of Disaster Information Conference
• /
• 2016.11a
• /
• pp.283-286
• /
• 2016

국내에 다수의 공동주택이 건설되고 있거나 공사중에 있으며 그 수요 또한 향후 지속적으로 증가할 예정이다. 그러나 이러한 증가추세의 공동주택 중 대피공간 규정이 신설된 1992년 이전에 시공된 건축물은 현재에도 대피공간 및 피난시설이 부재한 상황이다. 또한, 현재 계획 및 시공, 준공된 준초고층의 공동주택에 설치되어 있는 대피공간 및 이에 준하는 시설은 사생활 침해 및 타 용도 공간 활용 등으로 기능이 상실되어 있다. 이에 따라 공동주택 피난 및 대피공간에 대한 실효성을 검토할 필요가 있고 타 시 도의 선진사례를 분석하여 정책적 제안을 마련할 필요가 있다. 본 연구는 공동주택 피난시설의 효율성 강화를 위해 광주광역시의 공동주택 관련 현황 및 사례 조사와 관련 법규 분석을 통해 피난시설 및 대피공간의 문제점을 검토하고 효율성이 높은 대피시설 등을 활용할 수 있는 정책적 제언 및 인센티브 제도, 가이드라인 등 정책 대안을 제시하였다.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.1
• /
• pp.84-92
• /
• 2010

This paper presents the influence of the underground structure (such as cavern and tunnels) behavior according to the rock joint orientation and underground cavern size. In order to perform this research, numerical and experimental studies are carried out. Stress aspect was assessed by quantitative according two kind of factor. In the experimental study, the laboratory model tests are performed in the several ground conditions with different underground cavern size. The results obtained from the model tests are also verified and evaluated using the numerical analysis. Due to the underground cavern, it is found from this study that the stresses developed in archcrown, side wall of underground are increased with increasing the underground cavern size. It is also investigated that the rock joint direction is one of main influence factor as risk factor, to maintain the underground cavern stability. It may be expected that this research will provide the very useful information to evaluate the underground cavern stability.

• Tuberculosis and Respiratory Diseases
• /
• v.50 no.4
• /
• pp.484-492
• /
• 2001

Background : Pulmonary tuberculosis with a remaining cavitary lesion is considered to be a problem with the course of treatment. In particular, re-treatment cases tend to respond poorly to current anti-tuberculosis agents. Therefore the factors that are related with the poor closure of a cavitary lesion in pulmonary tuberculosis during treatment were evaluated. Methods : A retrospective review of the medical records and chest X -ray films of 68 patients who had chemotherapy for the pulmonary tuberculosis with cavitary lesions was made. All the patients had been followed up for more than 12 months at National Masan Tuberculosis Hospital as of Aug. 2000. Results : The male to female ratio was 3.9:1.72.4% of the patients were between 20 to 50 years of age. 66.2% of the cavitary lesions on the chest X-ray films were confined to the upper lung fields : 36.8% in the right upper lung field and 29.4% in the left upper lung field. 82.4% of the cavities were less than 40 mm in their size, and 83.8% were less than 6 mm thick. The cavitary lesions were closed in 48 cases and remained in 20 cases during a follow-up period of more than 12 months. The factors that are thought to affect to the outcomes of the cavities were age, past medication history, the number of unused drugs, and the number of sensitive drugs. Conclusion : In the treatment courses of pulmonary tuberculosis with cavitary lesions, the following factors are associated with less desirable outcome:an age over 45, a past medication history of more than 2 courses of treatment, The number of unused drugs not exceeding average 6 and the number of sensitive drugs not exceeding average 7.