• Title/Summary/Keyword: Urban Phenomenon

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Comparative Analysis of Land Use Change Model at Gapcheon Watershed (갑천 유역을 대상으로 토지이용예측모델 비교 분석)

  • Kwon, PilJu;Ryu, Jichul;Lee, Dong Jun;Han, Jeongho;Sung, Yunsoo;Lim, Kyoung Jae;Kim, Ki-Sung
    • Journal of Korean Society on Water Environment
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    • v.32 no.6
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    • pp.552-561
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    • 2016
  • For the prediction of hydrologic phenomenon, predicting future land use change is a very important task. This study aimed to compare and analyze the two land use change models, CLUE-S and SLEUTH3-R. The analysis of two models were performed based on the MSR value such that the model with more reliable MSR value can be recommended as an appropriate land use change prediction model. The model performance was examined by applying to the Gapcheon A watershed. Land use map of the study area of 2007 obtained from the Ministry of Environment was compared with the predicted land use map obtained from each of the two models. The result from both models showed somewhat similar results. The MSR value obtained from CLUE-S was 0.564, while that from SLEUTH3-R was 0.586. However, when land use map of 2010 was compared with predicted land use map obtained from the two models in same manner, the MSR value obtained from CLUE-S' was 0.500 while that from SLEUTH3-R was decreased to 0.397, an approximately 32.3% decrease from previous value of 2007. Moreover, SLEUTH3-R showed more sensitivity in conversion of urban areas, as compared to other land use types. Therefore, for the prediction of future land use change, CLUE-S model is more reliable than SLEUTH3-R.

Strain-rate-dependent Consolidation Characteristics of Busan Clay (부산점토의 변형률 속도 의존적인 압밀특성)

  • Kim Yun-Tae;Jo Sang-Chan;Jo Gi-Young
    • Journal of the Korean Geotechnical Society
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    • v.21 no.6
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    • pp.127-135
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    • 2005
  • In order to analyze effects of strain rate on consolidation characteristics of Busan clay, a series of constant rate of strain (CRS) consolidation tests with different strain rate and incremental loading tests (ILT) were performed. From experimental test results on Busan clay, it was found that the preconsolidation pressure was dependent on the corresponding strain rate occurring during consolidation process. Also, consolidation curves normalized with respect to preconsolidation pressure gave a unique stress-strain curve. Coefficient of consolidation and permeability estimated from CRS test had a tendency to converge to a certain value at normally consolidated range regardless of strain rate. An increase in excess pore pressure was observed after the end of loading without change of total stress on the incremental loading test, which phenomenon is called Mandel-Cryer effect. It was also found that rapid generation of excess pore pressure took place due to collapse of soil structure as effective stress approached to preconsolidation pressure.

Evaluation of Liquefaction Triggering for the Pohang Area Based on SPT and CPT Tests (SPT와 CPT 지반조사결과에 기초한 포항지역 액상화 위험도 평가)

  • Kim, Yeon-Jun;Ko, Kil-Wan;Kim, Byung-Min;Park, Du-Hee;Kim, Ki-Seog;Han, Jin-Tae;Kim, Dong-Soo
    • Journal of the Korean Geotechnical Society
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    • v.36 no.10
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    • pp.57-71
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    • 2020
  • Liquefaction-induced sand boils were observed during the Pohang earthquake (Moment magnitude, 5.4) on November 15, 2017, specifically in the region of agricultural fields and park areas near the epicenter. This was recorded as the first observed liquefaction phenomenon in Korea. This paper analyzes liquefaction potentials at the key sites at Pohang area. The simplified methods and current design standard were used to evaluate the occurrence of liquefaction. The seismic demand was estimated based on the NGA-WEST2 ground motion prediction equations (GMPEs). The liquefaction resistance of the ground was determined using the in-situ tests: standard penetration test (SPT) and cone penetration test (CPT). The liquefaction potentials were quantified by liquefaction potential index (LPI), which were compared with those from the previous studies.

Cost Analysis of Construction Phase in Basement Composite Wall Form (지하 합벽 거푸집의 시공단계별 원가 분석에 관한 연구)

  • Choi, Oh-Young;Heo, Kyoung-Moo;Kim, Tae-Hui;Kim, Jae-Yeob;Kim, Gwang-Hee
    • Journal of the Korea Institute of Building Construction
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    • v.9 no.6
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    • pp.189-195
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    • 2009
  • Recently, the urban centralization phenomenon appears to be growing. As a result, many vigorous efforts for the use of underground space are being made. In particular, the basement depth of construction in the downtown area has deepened and construction is often done close to adjacent buildings. In this case, generally, the underground construction approach mainly used is the composite basement wall system. However, a cost analysis of the basement composite wall system does not exist. Therefore, in this study, the cost of the composite basement wall system was analyzed. The percentage breakdown of costs were: buttress work processes, 3% form work processes, 26% reinforcement work processes, 12% support work processes, 42% and other processes,17%. Accordingly, it will be necessary when developing new technology and construction methods to determine the development focus.

Spatial Characteristics of Longevity Degree in Korea (한국 장수도(長壽度) 변화의 공간적 특성)

  • Park, Sam-Ock;Jeong, Eun-Jin;Song, Kyung-Un
    • Journal of the Korean association of regional geographers
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    • v.11 no.2
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    • pp.187-210
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    • 2005
  • The purpose of this study is to examine the spatial characteristics of the longevity phenomenon and long-live areas in Korea where a rapid aging process is undergoing. Population data from 1966 to 2000 at the county level are analyzed to understand aging process and changes of longevity degree by regions. The relationship between the degree of longevity and a region's natural environments and distance to a metropolis has been analyzed to understand regional factors of longevity. The findings from the study are summarized as follows. Firstly, the rural regions in Honam show the highest degree of longevity in the nation. Secondly, the areas of the high degree of longevity has recently shifted and/or expanded from the islands and seashore areas of southwestern region to inland mountainous areas around Soback Mountain. Southern islands and seashore regions used to show the nation's highest degree of longevity in the 1970s. Thirdly, the analysis of regional environment factors indicated that longevity has more related to a precipitation and an average altitude than temperature. Fourthly, in order to identify the longevity factors in urban areas, social and economic factors should be considered beyond the natural environmental factors.

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A Study on the Construction of Waste Incineration Facility by Pyrolysis Type in Iksan City (익산시의 열분해방식 폐기물 소각시설 건설에 관한 연구)

  • 육찬남
    • Journal of environmental and Sanitary engineering
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    • v.17 no.3
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    • pp.60-66
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    • 2002
  • Iksan city is planning to construct a waste incinerator on the site of about $110,000\textrm{m}^2$ in size that will be selected from a public bid(Oct.~Nov.2002)in the wake of expiration by June 2003 of use for Hamyeol fill-up ground. Science it has usually been difficult to find sites for filling-up or incinerating facilities owing to NIMBY phenomenon, it is badly requested to employ up-to-date technology for processing wastes without environmental pollution. The conflicts between the administrative authorities and community people with regard to construction of incineration facilities, fill-up ground and facilities for waste processing or recycling are not the matters of just today but are increasingly deepening and spreading countrywide. There seems to be no prospect for these conflicts to be amicably settled through dialogues. They rather become a social disease inflicting the whole country like an epidemic. It is therefore believed to be necessary to introduce measures to design and build environment-friendly facilities that may be accepted by residents as not abominable ones but be used as amusing place while they watch the daily operation of them as watchdogs. Iksan city's plan to construct environment-friendly waste incineration facilities of pyrolysis type without chimney has undergone the process of public hearings and explanatory gatherings from every class of Iksan citizens to get consensus but is still delayed due mainly to be the failure of inducing foreign investments. Pyrolysis technology has two advantages ; first, environment-friendly due to less emission of second pollutants ; second, production of by-products highly valuable as resources. It Is known that Germany has recently begun installation and operation of pyrolysis facility urban wastes, an evidence indicating that pyrolysis method will be widely applied to cope with the tightened regulation to preserve environment worldwide.

Characteristics of Road Runoff depending on the Rainfall Intensity (강우강도에 따른 노면유출수의 유출 특성)

  • Kim, Seog-Ku;Kim, Young-Im;Yun, Sang-Leen;Lee, Yong-Jae;Kim, Ree-Ho;Kim, Jong-Oh
    • Journal of Korean Society on Water Environment
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    • v.20 no.5
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    • pp.494-499
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    • 2004
  • Growth in population and urbanization has progressively increased the loadings of pollutants from non-point sources as well as point sources. Therefore, it is necessary to manage both point and non-point sources contaminations for protecting water environment and improving water quality. This study investigated the characteristics of pollutant release over a wide range of rainfall intensities as a requisite to control road runoff that accounts for the largest portion of non-point source contamination in urban areas. Samples of runoff rainwater collected from real road surfaces were analyzed for physicochemical parameters such as pH, suspended solids, and heavy metals. A experimental model road ($30cm{\times}30cm$) was also used to evaluate wash-off properties of pollutants deposited on the surface as functions of time and rainfall intensity. Analysis of runoff samples on rain events showed that the pollutant wash-off patterns for heavy metal and suspended solids were similar. This implies that the particles in rainwater adsorb heavy metals. Experiments using the model road made of impervious asphalt demonstrate a strong first flush phenomenon. At high rainfall intensity, approximately 80% of total pollutants were released within 15 min. The pollutant wash-off rates rapidly increase from 9 mm/hr to 12 mm/hr of rainfall intensity and decrease over 12 mm/hr of rainfall intensity.

Analysis on the Structural Change of Chonsei and Monthly Rent Market (전월세시장 구조변화 분석에 관한 연구)

  • Park, Sang-Hak;Kim, Yong-Soon
    • Land and Housing Review
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    • v.3 no.4
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    • pp.379-387
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    • 2012
  • This paper analyzes characteristics and changing phenomenon of Chonsei & monthly rental real estate market based on a survey of participants. The frequency analysis, mean analysis, and cross-table analysis was utilized for this study, and a survey for 2,000 rental market participants was accomplished. The survey result of tenants and land-owners regarding the Chonsei market stability indicates the expansion of public housing supply is needed together with lowering of mortgage related restrictions. The major conclusions include that the expansion of public housing and rental supports for low-income families are needed, due to the population structural change and an aging society. In addition, survey result suggests the tenants require the expansion of public housing supply for the residence stability.

A study on thermal simulation for extensive green roof system using a plant canopy model (식생캐노피모델을 통한 저관리 조방형 옥상녹화시스템의 열해석 전산모의에 관한 연구)

  • Kim, Tae Han
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.15 no.2
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    • pp.137-147
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    • 2012
  • GRS is an effective urban ecology restoration technique that can manage a variety of environmental functions such as ecological restoration, rainwater spill control and island heat effect from a low-impact development standpoint that can be utilized in new construction and retrofits. Recently, quantitative evaluation studies, both domestic and abroad, in the areas related to these functions, including near-earth surface climate phenomenon, heavy rainwater regulation, thermal environment of buildings, have been actively underway, and there is a trend to standardize in the form of technological standards. In particular, centered on the advanced European countries, studies of standardizing the specific insulation capability of buildings with green system that comprehensively includes the green roof, from the perspective of replacing the exterior materials of existing buildings, are in progress. The limitation of related studies in the difficulties associated with deriving results that reflect material characteristics of continuously evolving systems due in part to not having sufficiently considered the main components of green system, mechanisms of vegetation, soils. This study attempts to derive, through EnergyPlus, the effects that the vegetation-related indicators such as vegetation height, FCV, etc. have on building energy load, by interpreting vegetation and soil mechanisms through plant canopy model and using an ecological standard indicator LAI that represent the condition of plant growth. Through this, the interpretations that assume green roof system as simple heat insulation will be complemented and a more practical building energy performance evaluation method that reflects numerical methods for heat fluxes phenomena that occur between ecology restoration systems comprised of plants and soil and the ambient space.

A Study on Private Security in the 1970s (1970년대의 민간경비연구)

  • Ahn, Hwang Kwon
    • Convergence Security Journal
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    • v.13 no.2
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    • pp.15-24
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    • 2013
  • In the 1960s, economic growth served to step up industrialization and urbanization, which was concurrent with th e urban concentration of population, and this phenomenon led to an increase in crime, and there was a rapid increase in demand for security at the same time. So the law enforcement authorities instituted the security service act in a move to secure quasi-police force. The enactment of the security service act has been put in force up to now, fueling the growth of security business. Mean while, the security industry has attained a splendid growth as one of growth industries, and it's required to look back on the past to determine new directions for the industry to make a new leap forward. Thus, the 1970s was a period to lay the groundwork for Korean private security, and the purpose of this study was to examine the social environments of the 1970s related to private security and what accelerated the development of private security.