• Title/Summary/Keyword: Spatial cluster analysis

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Aanalysis the Structure of Heat Environment in Daegu Using Landsat-8 (Landsat-8을 활용한 대구시 열 환경구조 분석)

  • Kim, Jun Hyun;Choi, Jin Ho
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.32 no.4_1
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    • pp.327-333
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    • 2014
  • To improve thermal environments in urban area, the structural characteristic analysis of thermal environments of the certain area should be preceded to analyze and supplement its problems. With Landsat-8, we measured the centrality estimation, the distribution map, and the spatial statistical analysis of Daegu Metropolitan City in January and August, which of data applied in analyzing the structure of thermal environments following to its spatial property. The thermal infrared band of satellite images has been used to analyze the standard normal deviated scores, which extract the centrality, while the cluster map, based upon Local Local Moran's I, has composed for understanding the autocorrelation of local spatial within environment space structure. Understanding the distribution features as well as the pivot center of thermal environments with satellite images provides principle database for updating urban thermal environments' policies and plans; because those are reference materials that should have precedence over for diverse thermal environment policies.

Analysis Methodology of Industrial Integration by Spatial Unit: Based on Root Industry (공간단위별 산업집적 분석 방법 연구: 뿌리산업을 중심으로)

  • Kim, Seong-Hee
    • The Journal of the Korea Contents Association
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    • v.20 no.6
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    • pp.256-266
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    • 2020
  • Spatial distribution analysis of industrial locations plays a very important role in the establishment of relevant spatial policies and plans. The first thing to consider in this analysis is what analysis indicators and spatial units are used, because the interpretation of the analysis results may vary depending on the analysis indicators and the spatial units. Therefore, this study first examines various industrial integration indicators considering spatial autocorrelation and suggests the classification of regional types of industrial aggregation through the combination of related indicators. And then, this paper aims to empirically analyze the root industry by presenting a methodology for analyzing industrial integration by various spatial units such as individual locations, grids, and administrative districts. The results of the empirical analysis show that the grid in the spatial unit can be analyzed in more detail than the administrative unit. In addition, it is expected to overcome the limitations such as differences in interpretation that may occur due to the setting of spatial units. In the classification of regional types, the south-eastern region of Ulsan, Busan, and Changwon, and the western region of the SMA of Incheon, Hwaseong, and Ansan were analyzed as the industrial cluster type.

Estimating dark matter mass for the most massive high-z galaxy cluster, SPT-CL J2106-5844 using weak-lensing analysis with HST observations

  • Kim, Jinhyub;Jee, Myungkook James;Ko, Jongwan
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.1
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    • pp.67.2-67.2
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    • 2016
  • SPT-CL J2106-5844 is known to be one of the most massive galaxy clusters ($M_{200}{\sim}1.27{\times}10^{15}M_{sun}$) ever found at z > 1. Given its redshift (z ~ 1.132), the mass of this cluster estimated by Sunyaev-Zel'dovich effect and X-ray observation is too large compared with the current ${\Lambda}CDM$ cosmology prediction. Mass estimation from these methods can be biased because they require assumptions on hydrostatic equilibrium, which are not guaranteed to hold at such high redshift (about 40% of the current age of the Universe). Thus, we need to verify the mass of this interesting cluster using gravitational lensing, which does not require such assumptions. In this work, we present our preliminary result of dark matter mass and its spatial mass distribution of SPT-CL J2106-5844 using weak-lensing analysis based on HST optical/NIR deep imaging data. We compare mass estimates from different sources and discuss cosmological implications.

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Assessment of Water Quality using Multivariate Statistical Techniques: A Case Study of the Nakdong River Basin, Korea

  • Park, Seongmook;Kazama, Futaba;Lee, Shunhwa
    • Environmental Engineering Research
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    • v.19 no.3
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    • pp.197-203
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    • 2014
  • This study estimated spatial and seasonal variation of water quality to understand characteristics of Nakdong river basin, Korea. All together 11 parameters (discharge, water temperature, dissolved oxygen, 5-day biochemical oxygen demand, chemical oxygen demand, pH, suspended solids, electrical conductivity, total nitrogen, total phosphorus, and total organic carbon) at 22 different sites for the period of 2003-2011 were analyzed using multivariate statistical techniques (cluster analysis, principal component analysis and factor analysis). Hierarchical cluster analysis grouped whole river basin into three zones, i.e., relatively less polluted (LP), medium polluted (MP) and highly polluted (HP) based on similarity of water quality characteristics. The results of factor analysis/principal component analysis explained up to 83.0%, 81.7% and 82.7% of total variance in water quality data of LP, MP, and HP zones, respectively. The rotated components of PCA obtained from factor analysis indicate that the parameters responsible for water quality variations were mainly related to discharge and total pollution loads (non-point pollution source) in LP, MP and HP areas; organic and nutrient pollution in LP and HP zones; and temperature, DO and TN in LP zone. This study demonstrates the usefulness of multivariate statistical techniques for analysis and interpretation of multi-parameter, multi-location and multi-year data sets.

A Photometric Study of the Young Open Cluster IC 1805

  • Sung, Hwankyung;Lim, Beomdu;Bessell, M.S.;Hur, Hyeonoh;Yi, Jonghyuk;Chun, Moo-Young
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.2
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    • pp.41.2-41.2
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    • 2015
  • We have performed deep wide-field CCD photometry of the young open cluster IC 1805 in the famous star forming region W4, and obtained photometric data for more than 91,000 stars in the field of IC 1805 based on observations with the 3.6m CFHT and the AZT-22 1.5m telescope at Maidanak Astronomical Observatory in Uzbekistan. The photometric data cover an area $43^{\prime}{\times}45^{\prime}$ which is far larger and far deeper than any other optical observations made for the cluster. In order to select the young stellar objects with mid-IR excess emission, we have performed mid-IR photometry of the cluster using the archival images obtained with the Spitzer Space Telescope IRAC and MIPS instruments. From a preliminary analysis of the data, we determined the reddening law ($R_V=3.02{\pm}0.05$), distance modulus ($V_0-M_V=11.9{\pm}0.2$), and the spatial distribution of members.

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The rise and fall of dusty star formation in (proto-)clusters

  • Lee, Kyung-Soo
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.2
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    • pp.38.1-38.1
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    • 2019
  • The formation and evolution of galaxies is known to be fundamentally linked to the local environment in which they reside. In the highest-density cluster environments, galaxies tend to be more massive, have lower star formation rates and dust content, and a higher fraction have elliptical morphologies. The stellar populations of these cluster galaxies are older implying that they formed the bulk of their stars much earlier and have since evolved passively. Quantifying the specific environmental factors that contribute to shaping cluster galaxies over the Hubble time and measuring their early evolution can only be accomplished by directly tracing the galaxy growth in young clusters and forming porto-clusters. In this talk, I will present a novel technique designed to map out the total dust obscured star formation relative to where existing stars lie. I will demonstrate that this technique can be used 1) to determine if/where/when the activity is heightened or suppressed in dense cluster environment; 2) to measure the total mass and spatial distribution of stellar populations; and 3) to better inform theoretical models. Our ongoing work to extend this analysis out to protoclusters (z~2-4) will be discussed.

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Application of SOM for the Detection of Spatial Distribution considering the Analysis of Basic Statistics for Water Quality and Runoff Data (수질 및 유량자료의 기초통계량 분석에 따른 공간분포 파악을 위한 SOM의 적용)

  • Jin, Young-Hoon;Kim, Yong-Gu;Roh, Kyong-Bum;Park, Sung-Chun
    • Journal of Korean Society on Water Environment
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    • v.25 no.5
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    • pp.735-741
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    • 2009
  • In order to support the basic information for planning and performing the environment management such as Total Maximum Daily Loads (TMDLs), it is highly recommended to understand the spatial distribution of water quality and runoff data in the unit watersheds. Therefore, in the present study, we applied Self-Organizing Map (SOM) to detect the characteristics of spatial distribution of Biological Oxygen Demand (BOD) concentration and runoff data which have been measured in the Yeongsan, Seomjin, and Tamjin River basins. For the purpose, the input dataset for SOM was constructed with the mean, standard deviation, skewness, and kurtosis values of the respective data measured from the stations of 22-subbasins in the rivers. The results showed that the $4{\times}4$ array structure of SOM was selected by the trial and error method and the best performance was revealed when it classified the stations into three clusters according to the basic statistics. The cluster-1 and 2 were classified primarily by the skewness and kurtosis of runoff data and the cluster-3 including the basic statistics of YB_B, YB_C, and YB_D stations was clearly decomposed by the mean value of BOD concentration showing the worst condition of water quality among the three clusters. Consequently, the methodology based on the SOM proposed in the present study can be considered that it is highly applicable to detect the spatial distribution of BOD concentration and runoff data and it can be used effectively for the further utilization using different water quality items as a data analysis tool.

The Assessment of Air Quality Monitoring Network Considering the Change of Various Environmental Factors in Busan (부산지역의 다양한 환경적 요인의 변화에 따른 대기오염측정망 평가)

  • Yoo Eun-Chul;Park Ok-Hyun
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.4
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    • pp.405-420
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    • 2006
  • This study was conducted to understand the change of spatial environmental factors including populations, air pollution source and land-use in Busan, during the period of 1995 and 2004. Firstly, the grids (5 km $\times$ 5 km) were divided using the TM coordinates of Busan and the statistical data of populations and land-use were marked on each grid during studying period. Secondly, the SO$_2$, NO$_2$ and O$_3$ concentrations of areas where air quality monitoring station was not established were estimated on the basis of these air pollutants measured at close air quality monitoring station by kriging method. In order to understand spatial change of air pollution and to investigate duplication and reduction of existing stations, semivariogram, correlation and cluster analysis were carried out. This study showed that the population increased in 2004 only on 8 grids compared to in 1995. The spatial change of SO$_2$, NO$_2$ and O$_3$ was investigated by semivariogram in Busan area. As the results of semivariogram, the spatial change of 502 become smaller and simpler, while that of NO2,03 become larger and more complex in 2004 than in 1995, According to the result of correlation and cluster analysis, the reduction of measurement item or the relocation of air quality monitoring station can be needed in the high dense grid area.

The Developmental Directions and Classification of Regional Types Based on Natural Resources (자연자원에 기반한 지역유형분류와 발전방안)

  • Park, Jong-Jun;Yoon, Ki-Ran;Park, Chang-Sug
    • Journal of the Korean Institute of Landscape Architecture
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    • v.39 no.2
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    • pp.10-17
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    • 2011
  • The paradigm of the use and management of natural resources is changing. Wise use of natural resources can be achieved by enhancing their conservation value and, at the same time, taking them as an opportunity for regional development. It leads to an idea of pursuing regional development by making good use of natural resources. In this paper, natural resources were classified as living species resources, ecosystem and landscape resources, and non-living resources. The resources were divided into 27 detailed analysis indices. The administrative boundaries of 165 municipalities in Korea were defined as spatial analysis units. Finally, a spatial database of natural resources was built. To classify the regional types, we conducted factor analyses with a detailed index of natural resources and a cluster analysis with the factor value. As the result of the factor analysis, six factors have been deduced as follows: forest resources, landscape resources, coastal ecology resources, inland water resources, landform resources, and ecology visit resources. In addition, the cluster analyses were conducted for the points of the factors drawn. The final classification consists of nine groups, and appropriate methods for each regional development have been suggested. Results of this study will contribute to providing fundamental materials for site selection and objective-setting for regional development policies and planning in consideration of natural resources.

Assessment and Classification of Meteorological Drought Severity in North Korea (북한의 지역별 기상학적 가뭄의 평가와 유형분류)

  • Yoo, Seung-Hwan;Nam, Won-Ho;Jang, Min-Won;Choi, Jin-Yong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.50 no.4
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    • pp.3-15
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    • 2008
  • North Korea is one of the most vulnerable countries of the world for drought but still it is difficult to find scientific researches for understanding of the drought characteristics. This study analyzed the temporal and spatial distribution of meterological drought severity and classified the drought development types in North Korea. All eleven drought indices were tested such as seasonal rainfall, PDS, SPI and so on, and then drew the drought risk map by each indicator using frequency analysis and GIS(Geographic Information Systems) for twenty one meteorological stations. In addition meteorological drought characteristics in North Korea was classified to six patterns on Si/Gun administrative units using cluster analysis on the drought indicators. The cluster III has the strongly drought-resistant area due to sufficient rainfall and the cluster V was considered as the most drought-vulnerable area, Pungsan and Sinpo, because of the severest drought condition for eight drought indicators. The results of this study are expected to be provided for the basic understanding of regionalized drought severity and characteristics confronting the risk of drought from climate variations in North Korea.