• Title/Summary/Keyword: Facilities of the City

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Characterization of Area Installing Combined Geothermal Systems : Hydrogeological Properties of Aquifer (복합지열시스템에 대한 부지특성화: 대수층의 수리지질학적 특성)

  • Mok, Jong-Koo;Park, Yu-Chul;Park, Youngyun;Kim, Seung-Kyum;Oh, Jeong-Seok;Seonwoo, Eun-Mi
    • The Journal of Engineering Geology
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    • v.27 no.3
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    • pp.293-304
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    • 2017
  • This study was performed in order to hydrogeological analysis of aquifer, which is a necessary part for evaluating the efficiency of the combined well and open-closed loops geothermal (CWG) systems. CWG systems have been proposed for the effective utilization of geothermal energy by combining open loop geothermal systems and closed loop geothermal systems. Small aperture CWG systems and large aperture CWG systems were installed at a green house land with water curtain facilities in Chungju City. Aquifer tests include pumping tests and step-drawdown tests were conducted to analyse hydrogeological characteristics of aquifer in the study area. The transmissivity was estimated in the range of $13.49{\sim}58.99cm^2/sec$, and the storativity was estimated in the range of $1.13{\times}10^{-5}{\sim}5.20{\times}10^{-3}$. The geochemical analysis showed $Ca^{2+}$ ion and ${HCO_3}^-$ ion were dominant in groundwater. The Langelier Saturation Index and the Ryznar Stability Index showed low scaling potential of groundwater. In the analysis of vertical water temperature change, the geothermal gradient was estimated as $2.1^{\circ}C/100m$, which indicated the aquifer was enough for geothermal systems. In conclusion, groundwater is rich, can stably use geothermal heat, and it is less likely to cause deterioration of thermal energy efficiency by precipitation of carbonate minerals in study area. Therefore, the study area is suitable for installation of the combined geothermal system.

Stability analysis of an existing tunnel due to the excavation of a divergence tunnel emerging from double-deck tunnel (복층터널의 분기터널 굴착에 따른 기존터널의 안정성 분석)

  • Kim, Han-eol;Kim, Jung-Joo;Lee, Jae-Kook;Yoo, Han-Kyu
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.5
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    • pp.779-797
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    • 2017
  • Recently, underground road construction is attracting attention because the ground transportation facilities in the urban area have reached the saturation level and traffic volume has increased and the air pollution has risen. Construction of underground roads is not only reduce trafficjam in downtown but also design the city eco-friendly, so existing roads as well as new roads go underground. It is essential to construct divergence tunnels that serve as IC (interchage) and JC (Junction) when constructing underpasses. Therefore, the analysis of the effect of the existing tunnel by the divergence tunnel should be considered. In this study, numerical analysis is performed to analyze the effect of existing tunnel on the excavation of the divergence tunnel. The divergence tunnels were set in 5 cases at $45^{\circ}$ intervals in the clockwise direction starting from the lower part of the existing tunnel. In each case, numerical analyses were carried out by using the DCM (Displacement Controlled Model) for applying the volume loss of 0.5%, 1.0% and 1.5%. As a result, when the volume loss increased, the effect on displacement, fracture range, and effect on stability increased as well. In addition, it was confirmed that the divergence tunnel located directly underneath is the weakest for the stability, and the case where the divergence tunnel is located diagonally rather than the vertical and horizontal direction is found to be vulnerable to displacement and lining destruction.

Analysis of articles on water quality accidents in the water distribution networks using big data topic modelling and sentiment analysis (빅데이터 토픽모델링과 감성분석을 활용한 물공급과정에서의 수질사고 기사 분석)

  • Hong, Sung-Jin;Yoo, Do-Guen
    • Journal of Korea Water Resources Association
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    • v.55 no.spc1
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    • pp.1235-1249
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    • 2022
  • This study applied the web crawling technique for extracting big data news on water quality accidents in the water supply system and presented the algorithm in a procedural way to obtain accurate water quality accident news. In addition, in the case of a large-scale water quality accident, development patterns such as accident recognition, accident spread, accident response, and accident resolution appear according to the occurrence of an accident. That is, the analysis of the development of water quality accidents through key keywords and sentiment analysis for each stage was carried out in detail based on case studies, and the meanings were analyzed and derived. The proposed methodology was applied to the larval accident period of Incheon Metropolitan City in 2020 and analyzed. As a result, in a situation where the disclosure of information that directly affects consumers, such as water quality accidents, is restricted, the tone of news articles and media reports about water quality accidents with long-term damage in the event of an accident and the degree of consumer pride clearly change over time. could check This suggests the need to prepare consumer-centered policies to increase consumer positivity, although rapid restoration of facilities is very important for the development of water quality accidents from the supplier's point of view.

Characteristics of Mine Liner According to the Replacement Ratio of Nano-Silica and Silica-Fume (나노실리카 및 실리카흄 대체율에 따른 차수재의 특성)

  • Kang, Suk-Pyo;Lee, Hee-Ra;Kang, Hye-Ju;Nam, Seong-Young;Kim, Chun-Sik
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.1
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    • pp.66-73
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    • 2019
  • Approximately 80% of the mines are vacated or abandoned mines and are mostly left without suitable environmental treatment facilities. In the area around the abandoned mine site, problems such as drainage of acidic city drainage and leakage of leachate occur, and ground subsidence caused by this can cause a safety accident due to sink hole occurrence. In this study, flow, compressive strength, water uptake, pore and hydration characteristics were investigated to investigate the basic properties of liner and cover material based on the replacement ratio of nano silica and silica fume in the existing blast - furnace slag fine powder. As a result, as the substitution ratio of nano silica and silica fume increased, the flow and compressive strength of nano silica specimens increased and the absorption rate decreased. In the case of pore characteristics, the amount of pores decreased as the substitution ratio of nano silica and silica fume increased. Especially, the capillary porosity of 10-1,000 nm diameter decreased. Ray diffraction analysis and SEM measurement showed that the peak positions of the hydration products were almost the same when compared with the 5% alternative test samples of Plain and silica fume.

On-site Investigation of Hazardous Substances in Floor Dust of Several Primary Schools (일부 초등학교 바닥 먼지내 포함하고 있는 유해물질 성분에 대한 현장 평가)

  • Kim, Ki Youn;Kim, Hyeon Tae;Lee, Kwon Seob
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.24 no.4
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    • pp.478-483
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    • 2014
  • Objectives: The main objective of this study is to assess the levels of hazardous substances in floor dust in primary schools located in the city of Busan in Korea. Materials and Methods: An on-site investigation of three primary schools was performed between April and May 2013. The hazardous substances measured in this study were 14 heavy metals (Cu, Fe, Pb, Mn, Ni, Zn, Cr, Cd, As, Al, Sn, Co, Mo and Si) and the biological agents were bacteria, fungi and endotoxin). Results: Among the heavy metals, Cd, Co, Pb and Cr were not detected in the floor dust from the three primary schools. The mean levels of other heavy metals were as follows: $20({\pm}10)ng/cm^2$ for As, $30({\pm}20)ng/cm^2$ for Al, $5({\pm}4)ng/cm^2$ for Sn, $20({\pm}20)ng/cm^2$ for Mo, $1,340({\pm}620)ng/cm^2$ for Si, $110({\pm}100)ng/cm^2$ for Cu, $240({\pm}50)ng/cm^2$ for Fe, $30({\pm}30)ng/cm^2$ for Mn, $10({\pm}10)ng/cm^2$ for Ni, and $50({\pm}30)ng/cm^2$ for Zn. It was found that mean concentrations of bacteria, fungi and endotoxin in the floor dust of primary schools were $4.7{\time}10^7({\pm}2.2{\time}10^7)cfu/cm^2$, $6.3{\time}10^6({\pm}6.4{\time}10^6)cfu/cm^2$, and $8,140({\pm}5,801)EU/cm^2$, respectively. The predominant species identified in the floor dust of the primary schools were Pseudomonas spp. for bacteria and Penicillium spp.,Cladosporidium spp.,and Aspergillus spp. for fungi, which would be somewhat similar to the microbial distribution pattern of other general environments. Conclusions: Based on the results obtained from this study, the levels of heavy metals, microbes and endotoxin distributed in the floor dust of primary school were higher than those reported for other general facilities. Thus, preventive measures should be prepared for the health care of children.

A Study on the Development of Feasibility Evaluation Model for Establishment of Public Libraries (공공도서관 설립 사전 타당성 평가모형 개발 연구)

  • Sin-Young, Kim;Hee-Yoon, Yoon
    • Journal of the Korean Society for Library and Information Science
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    • v.56 no.4
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    • pp.101-127
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    • 2022
  • Article 31(1) of the Libraries Act(Act No. 18547), which was completely revised on December 7, 2021, stipulates that "the head of a local government or the superintendent of a city/provincial office of education must formulate a plan for the establishment and operation of a public library in advance and obtain the pre-evaluation of the feasibility of establishing a public library from the Minister of Culture, Sports and Tourism." Through the preliminary feasibility evaluation at the construction stage of the public library, it is possible to adjust distribution to improve the adequacy of scale and resolve regional imbalances and gaps. In addition, it is expected to increase service satisfaction and operational enhancement by inducing faithful securing of core infrastructure (librarians, collection, facilities, systems, etc.) in terms of balanced regional development and public library construction. The purpose of this study is to develop and present the basic direction and feasibility evaluation model for establishment of public libraries. The proposed evaluation model is expected to secure the legal basis and institutional legitimacy of the pre-evaluation system for public library establishment and to prevent waste of tax due to poor construction and operation of public libraries.

Hydrogeochemical characteristics of urban groundwater in Seoul

  • Lee, Ju-Hee;Yun, Seong-Taek;Kwon, Jang-Soon;Kim, Dong-Seung;Park, Seong-Sook
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2004.04a
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    • pp.472-472
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    • 2004
  • Numerous studies on urban groundwater have been carried out in many other countries. Urban groundwater shows a unique hydrologic system because of complex urban characteristics such as road pavement, sewers and public water supply systems. These urban facilities may change the characteristics of groundwater recharge but contaminate its quality as well. There have been several researches on urban groundwater in Seoul. Seoul has been industrialized very rapidly so that the city has large population. The recent population in Seoul amounts to more than ten millions, corresponding to a very high density of about 17, 000 people/km$^2$. Therefore, many factors affect the groundwater quality and quantity in Seoul. Nowadays, groundwater in Seoul is being extracted for construction, industrial use, and drinking and so on. There are 15, 714 wells in Seoul and its annual usage is 41, 425, 977m$^3$(in 2001). Therefore, systematic studies are needed to properly manage and use the groundwater in Seoul. The purposes of this study in progress are to identify geochemical characteristics of groundwater in Seoul and to determine the extent of groundwater contamination and its relationship with urban characteristics. For this study, groundwater was sampled from more than 400 preexisting wells that were randomly selected throughout the Seoul area. For all samples, major cations together with Si, Al, Fe, Pb, Hg For 200 samples among them, TCE, PCE, BTEX were also analyzed by GC. Our study shows that groundwater types of Seoul are distributed broadly from Ca-HCO$_3$ type to Ca-Cl+NO$_3$ type. The latter type indicates anthropogenic contamination. Among cations, Ca is generally high in most samples. In some samples, Na and K are dominant. The dominant anions change widely from HCO$_3$ to Cl+NO$_3$. The anion composition is considered to effectively indicate the contribution of distinct anthropogenic sources. In addition, major ions are positively proportional to total dissolved solid (TDS) except K and NO$_3$. Thus, we consider that TDS may be used as an effective indicator of the extent of pollution. However, the increase of TDS may result from increased water-rock interaction. To determine the extent of groundwater contamination, it is needed to figure out the baseline water quality in Seoul. Furthermore, detailed geochemical studies are required to find out pollution sources and their corresponding hydrochemical parameters.

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A Study on Facility Changes according to Changes in the Urban Park Type in Korea - Focus on Parks in Seoul - (국내 도시공원 유형변경에 따른 시설변화 연구 - 서울시 공원을 중심으로 -)

  • Ko, Ha-jung
    • Journal of the Korean Institute of Landscape Architecture
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    • v.50 no.2
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    • pp.76-88
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    • 2022
  • Urban parks play the role of providing leisure spaces for people in their everyday life along with serving ecological functions in the city. Although urban parks aim to satisfy the needs of users visiting the park, most urban parks are currently uniformly created and maintained without considering the environmental characteristics based on the needs of users. This study thus analyzed parks that underwent modifications in line with the revised Park Act in 2005. There were 45 parks whose types were legally changed, of which 21 were changed from children's parks to small parks, and 19 were changed to utilize and highlight the themes such as cultural parks and historical parks. Among the parks whose types have changed, the ratio of amenities in cultural and historic parks has increased, while the facility area in small parks has decreased and the green area has increased in its place. As a result of analyzing the changes to the park facility area, it was confirmed that increasing park amenities has a positive effect in pursuing revitalization of use through park maintenance, but has a negative consequence of significantly decreasing green area. It is necessary to reorganize the park type classification system to reflect the park environment and prepare guidelines for a new installation standard by park type to expand the net function of parks in cities and maintain the sustainable ecological environment. Through in-depth discussions on the facilities of park types, it is anticipated that innovative and multilateral research could be conducted to prepare improvement measures tailored to the guidelines of urban park types in years to come.

Concepts of Disaster Prevention Design for Safety in the Future Society

  • Noh, Hwang-Woo;Kitagawa, Keiko;Oh, Yong-Sun
    • International Journal of Contents
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    • v.10 no.1
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    • pp.54-61
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    • 2014
  • In this paper, we propose a pioneering concept of DPD(Disaster Prevention Design) to realize a securable society in the future. Features of danger in the future society are expected to be diverse, abrupt occurring, large scale, and complicated ways. Due to increment of dangers with their features of uncertainty, interactivity, complexity, and accumulation, human-oriented design concept naturally participates in activities to prevent our society against disasters effectively. We presented DPD is an essential design activity in order to cope with dangers expected in the future societies as well as realize securable environments. DPD is also an integrated design aids including preemptive protections, rapid preparing, recovery, and interactive cooperation. We also expect these activities of DPD is effective for generation of new values in the market, satisfaction of social needs, expansion of design industry, and a novel chance for development in the future society. Throughout this paper, we submit various aspects of DPD concepts including definition, classification, scope, necessity, strategy, influencing elements, process, and its principle. We expect these concepts will be the seed and/or basement of DPD research for the future works. For the direction of study for DPD in the future, we emphasize alarm system for preemptive protection rather than recovery strategy for the damage occurred. We also need to research about progressive prevention techniques and convergence with other areas of design. In order to transfer the concept of product design from facility-oriented mechanism to human-oriented one, we should develop new kinds of city basis facilities, public-sense design concepts referred to social weak-party, e-Learning content design preparing disasters, and virtual simulation design etc. On the other hand, we have to establish laws and regulations to force central and/or provincial governments to have these DPD strategies applying their regional properties. Modern design activities are expanding to UI(user interface) content design area overcoming the conventional design concept of product and/or service. In addition, designers are recognized as art directors or life stylists who will change the human life and create the social value. DPD can be divided into prevention design, preparedness design, response design, and recovery design. Five strategies for successful DPD are Precaution-oriented, Human-oriented, Sense-oriented, Legislation, and Environment Friendly Strategies.

The Study on the Countermeasure Plans about Leakage, Explosion and Fire Accidents of Atmospheric Storage Tank (옥외저장탱크 누출, 폭발 및 화재사고 대응방안에 관한 고찰)

  • Lee, Gab-Kyoo
    • Fire Science and Engineering
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    • v.30 no.6
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    • pp.48-56
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    • 2016
  • A crude oil leakage from a large atmospheric storage tank occurred on 4 April 2014 at 14:50 in Ulsan City, while storing the crude oil in the tank. Emergency Rescue Control Group was deployed in the scene. The company, Fire Service Headquarters and associated agencies got together in Command Post (CP) for discussing an effective corresponding strategy. Many solution plans were drafted in the debate such as power down, stopping the facilities, checking the density of inflammable gas, suppressing oil evaporation, moving the leaked crude oil to a nearby tank and a processing plant and avoiding marine pollution. All the solutions were carried out in cooperation with several agencies and partners. The oil leakage accident was successfully settled up within the process of responding, The Fire Service Headquarters and the company thought that the most important thing was the suppression of oil evaporation and the elimination of ignition source. With Fire Service Headquarters and several agencies' every effort, an explosion and a fire didn't occurred in the scene. This study suggest the improvement of the operating system in Emergency Rescue Control Group in case of petroleum leakage, explosion and fire accidents of atmospheric storage tank, different from a ordinary disaster. Assuming that petroleum leakage in atmospheric storage tank develop the explosion and fire accidents, the spreading speed of the flame and the burning time was experimented and compared with each other. Furthermore, this study concentrates on the effective field response plan prepared for the afterward explosion and fire accidents from petroleum leak in a storage tank, with the database experimented and analyzed in accordance with the angle of radiation in the foam nozzle and the pressure of pumping in a fire engine.