• Membrane and Water Treatment
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• 제13권5호
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• pp.245-257
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• 2022

Water quality characteristics and their spatial variations in the Nakdong River were statistically analyzed by multivariate techniques including correlation analysis, CA, and FA/PCA based on water quality parameters for 17 sites over 2017-2019, yielding PI values for primary factors. Site 10 indicated the highest parameter concentrations, and results of pearson's correlation analysis suggest that non-biodegradable organic matter had been distributed on the site. Five clusters were identified in order of descending pollution levels: I (Ib > Ia) > II (IIa > IIb) > III. Spatial variations started from sub-cluster Ib in which Daegu city and Geumho-river are joined. T-P, PO4-P, SS, COD, and TOC corresponded to VF 1 and 2, which were found to be principal components with strong influence on water quality. Sub-cluster Ib was strongly influenced by NO3-N and T-N compared to other clusters. According to the PIs, water quality pollution deteriorated due to non-biodegradable organic matter, nitrogen- and phosphorus-based nutrient salts in the middle and lower reaches, illustrating worsening water pollution due to inflows of anthropogenic sources on the Geumho-river, i.e., sewage and wastewater, discharged from Site 10, at which there is a concentration of urban, agricultural, and industrial areas.

• Environmental Analysis Health and Toxicology
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• 제29권
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• pp.5.1-5.7
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• 2014

Objectives Numerous studies have revealed the adverse health effects of acute and chronic exposure to particulate matter less than $10{\mu}m$ in aerodynamic diameter ($PM_{10}$). The aim of the present study was to examine the spatial distribution of $PM_{10}$ concentrations and cardiovascular mortality and to investigate the spatial correlation between $PM_{10}$ and cardiovascular mortality using spatial scan statistic (SaTScan) and a regression model. Methods From 2008 to 2010, the spatial distribution of $PM_{10}$ in the Seoul metropolitan area was examined via kriging. In addition, a group of cardiovascular mortality cases was analyzed using SaTScan-based cluster exploration. Geographically weighted regression (GWR) was applied to investigate the correlation between $PM_{10}$ concentrations and cardiovascular mortality. Results An examination of the regional distribution of the cardiovascular mortality was higher in provincial districts (gu) belonging to Incheon and the northern part of Gyeonggi-do than in other regions. In a comparison of $PM_{10}$ concentrations and mortality cluster (MC) regions, all those belonging to MC 1 and MC 2 were found to belong to particulate matter (PM) 1 and PM 2 with high concentrations of air pollutants. In addition, the GWR showed that $PM_{10}$ has a statistically significant relation to cardiovascular mortality. Conclusions To investigate the relation between air pollution and health impact, spatial analyses can be utilized based on kriging, cluster exploration, and GWR for a more systematic and quantitative analysis. It has been proven that cardiovascular mortality is spatially related to the concentration of $PM_{10}$.

• 한국환경과학회지
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• 제30권9호
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• pp.763-777
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• 2021

The spatial characteristics of typhoon-class strong wind during the non-typhoon period were analyzed using, a cluster analysis of the observational data and of special strong wind advisories and, warnings issued by the Korean Meteorological Administration. On the Korean Peninsula, strong winds during non-typhoon periods showed a wide variety of spatial characteristics. In particular, the cluster analysis showed that strong winds could be classified into six clusters on the Korean Peninsula, and that the spatial distribution, occurrence rate of strong winds, and strong wind speed in each cluster were complex and diverse. In addition, our analysis of the frequency of issuance of special strong wind warnings showed a significant difference in the average frequency of strong wind warnings issued in metropolitan cities, with relatively high numbers of warnings issued in Gyeongsangbuk-do and, Jeollanam-do, and low numbers of warning issued inland and in other metropolitan cities. As a result of the changing trend in warnings issued from 2004 to 2019, Ulsan and Busan can be interpreted as having a relatively high number of warnings; the frequency of strong wind warnings issuances and strong wind occurrences in these cities is increasing rapidly. Based on the results of this study, it is necessary to identify areas with similar strong wind characteristics and consider specific regional standards in terms of disaster prevention.

• Geomechanics and Engineering
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• 제25권2호
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• pp.135-142
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• 2021

This study provided a new research perspective for processing and analyzing AE data to evaluate rock failure. Cluster method and information entropy theory were introduced to investigate temporal and spatial correlation of acoustic emission (AE) events during the rock failure process. Laboratory experiments of granite subjected to compression were carried out, accompanied by real-time acoustic emission monitoring. The cumulative length and dip angle curves of single links were fitted by different distribution models and distribution functions of link length and directionality were determined. Spatial scale and directionality of AE event distribution, which are characterized by two parameters, i.e., spatial correlation length and spatial correlation directionality, were studied with the normalized applied stress. The entropies of link length and link directionality were also discussed. The results show that the distribution of accumulative link length and directionality obeys Weibull distribution. Spatial correlation length shows an upward trend preceding rock failure, while there are no remarkable upward or downward trends in spatial correlation directionality. There are obvious downward trends in entropies of link length and directionality. This research could enrich mathematical methods for processing AE data and facilitate the early-warning of rock failure-related geological disasters.

• 한국주거학회논문집
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• 제17권5호
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• pp.147-157
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• 2006

A study on Composing Unit Spaces of Apartment Houses according to the Differentiation in Lifestyle by survey on preferences. The purpose of this study is to propose composition models of unit spaces for 85m2 net area apartment houses by lifestyle types. This study set up a hypothesis that there is a critical divergence of preferences in composition types of unit spaces according to lifestyle. To prove the hypothesis, investigation on variable floor plans of apartments to extract spatial composition types of units and questionnaire survey on lifestyleand preferences for composition types were implemented. To extract several factors regarding, characteristics of lifestyle, factor analysis, was implemented for each variable. Cluster analysis was conducted to cluster interviewees by similarity of lifestyle. To identify and define how each factor reacts, ANOVA and cross tabulation analysis between factors and clusters were used. The type of spatial composition was analyzed by plane characteristic, spatial relation and spatial usability on the basis of apartment plate type. As a result, lifestyle was divided into three types: reasonable lifestyle, trend-seeking lifestyle and conservative lifestyle. As, the result of investigating characteristics for the type of spatial composition according to the type of lifestyle, preferred types and main districts were different. Therefore, the hypothesis was proved.

• Communications for Statistical Applications and Methods
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• 제18권4호
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• pp.549-557
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• 2011

In this paper, we apply cluster analysis to "Okayama parking data" that is one of the spatial point patterns data that includes locations and the fare structure of car parking space in Okayama central area. This study classifies the characteristics of small areas through Okayama parking data as well as visualizes the results of the cluster analysis. We develop web applications that connect the results of a cluster analysis and overlay objects including points of balloons and rectangles of small areas over a map of Okayama central area.

• 품질경영학회지
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• 제44권3호
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• pp.677-688
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• 2016

Purpose: In this study, we examine the effects of circulatory diseases mortality in South Korea 2005-2013 using the air pollution index, Methods: We cluster the region of high risk mortality by SaTScan$^{TM}$9.3.1 and compare this result with the regional distribution of air pollution. We use the Geographically Weighted Regression (GWR) to consider the spatial heterogeneity of data collected by administrative district in order to estimate the model. As GWR is spatial analysis techniques utilizing the spatial information, regression model estimated for each region on the assumption that regression coefficients are different by region. Results: As a result of estimating model of the collected air pollution index, circulatory diseases mortality data combined with the spatial information, GWR was found to solve the problem of spatial autocorrelation and increase the fit of the model than OLS regression model. Conclusion: GWR is used to select the air pollution affecting the disease each year, the K-means cluster analysis discover the characteristics of the distribution of air pollution by region.

• 한국지리정보학회지
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• 제13권4호
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• pp.170-180
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• 2010

지하공간 개발의 증가에 따라 지층단면도 등 다양한 형태로 제공되는 지하공간 정보모델의 신뢰성이 요구되고 있다. 그러나 지반은 근본적으로 불확실하며, 이를 표현하는 정보모델도 자료부족, 해석표준 부재 등의 비통계적 요인과 외부환경 변수라는 통계적 요인으로 불확실성을 가진다. 따라서, 현재의 모델 생성은 고도로 훈련된 전문가에 의해 이뤄지고 있다. 본 연구는 지반공학 전문가의 경험과 지식에서 시맨틱을 추출하고, 이를 온톨로지 모델과 정보량으로 정량화하였다. 정량화한 온톨로지 모델은 군집분석의 클러스터간 거리계산에 적용하여 시맨틱을 고려한 군집분석 방법론을 제안하였다. 본 제안 방법을 실험지역에 적용한 결과 기존 K-Means 방법에 비해 전문가의 해석과 유사한 결과를 도출하였으며, 수작업으로는 어려운 대용량 데이터를 손쉽게 처리하고 3차원 GIS로 가시화가 가능하였다. 본 연구를 통해 지반공학 전문가의 도움 없이도, 그 경험을 고려하면서 대량의 지반정보 데이터를 효과적으로 처리하여 신뢰성 있는 지하공간 정보모델을 생성할 수 있을 것이다.

• 한국경제지리학회지
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• 제19권3호
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• pp.437-456
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• 2016

본 연구의 목적은 공연예술 산업의 입지적 특성을 파악하고, 그들의 지역 경제와의 연계성을 분석하는 것이다. 이를 위하여 공연예술 산업이 가장 집중되어 있는 서울을 대상으로 소비자가 관련시설이 있는 장소를 방문해야 하는 소비의 유사성을 지닌 갤러리와 영화 상영관의 각 사업체의 주소자료를 이용하여 커널밀도분석과 공간적 자기상관성(Spatial Autocorrelation)분석을 실시한다. 특히 LISA(Local Indicator of Spatial Association)를 적용하여 국지적 핫스팟을 확인한다. 분석 결과 갤러리와 영화 상영관의 분산 분포와 달리 공연장은 대학로 일대를 중심으로 응집된 단일 핫스팟이 나타난다. 대학로 일대를 중심으로 하는 공연장 밀집지역에는 공연예술 산업의 가치사슬을 구성하는 다양한 활동들이 인근에 밀집분포하며 공연예술 산업의 클러스터를 형성하는 입지적 특성이 파악된다. 또한 다중회귀분석을 통하여 공연장의 분포를 설명하는 경제활동을 파악하여 지역 경제경관과의 연계성을 분석한다.

• 한국환경보건학회지
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• 제38권5호
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• pp.369-379
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• 2012

Objectives: Spatial analysis is useful for understanding complicated causal relationships. This paper focuses trends and appling methods for spatial analysis associated with environmental asbestos exposure. Methods: Literature review and reflection of experience of authors were conducted to know academic background of spatial analysis, appling methods on epidemiology and asbestos exposure. Results: Spatial analysis based on spatial autocorrelation provides a variety of methods through which to conduct mapping, cluster analysis, diffusion, interpolation, and identification. Cause of disease occurrence can be investigated through spatial analysis. Appropriate methods can be applied according to contagiousness and continuity. Spatial analysis for asbestos exposure source is needed to study asbestos related diseases. Although a great amount of research has used spatial analysis to study exposure assessment and distribution of disease occurrence, these studies tend to focus on the construction of a thematic map without different forms of analysis. Recently, spatial analysis has been advanced by merging with web tools, mobile computing, statistical packages, social network analysis, and big data. Conclusions: Because the trend in spatial analysis has evolved from simple marking into a variety of forms of analyses, environmental researchers including asbestos exposure study are required to be aware of recent trends.