• Title/Summary/Keyword: spatial cluster

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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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A Comparison of Daedeok Innopolis Cluster with the San Diego Biotechnology Cluster

  • Kim, Sang-Tae;An, Gi-Don
    • World Technopolis Review
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    • v.1 no.2
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    • pp.118-128
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    • 2012
  • This paper suggests policy implications for Daedeok Innopolis (DI) in Daejeon by comparing the development and problems of DI with the San Diego biotechnology cluster. DI has strengthened its capabilities for technology commercialization and business activities after having created and managed by the Korean central government. While DI has been successful in increasing the number of institutes, researchers, research activities, however, its dynamism is not rigorous enough to be a regional innovative system. San Diego's scientific and entrepreneurial community shows the importance of formulating social and spatial contexts for mutual interactions and engagements. In San Diego, UCSD and networking organizations, especially CONNECT, are central in promoting interactions and communications between regional constituents including entrepreneurs, academics and local governments. The mechanisms of San Diego biotechnology imply that DI should provide more attention to designing and developing social and geographical space that can unleash the creative power of social interactions. To build an innovative regional system, DI needs to renovate its space, public-private relationship and networking platforms.

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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Permitted Limit Setting Method for Data Transmission in Wireless Sensor Network (무선 센서 네트워크에서 데이터 전송 허용범위의 설정 방법)

  • Lee, Dae-hee;Cho, Kyoung-woo;Oh, Chang-heon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2018.05a
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    • pp.574-575
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    • 2018
  • The generation of redundant data according to the spatial-temporal correlation in a wireless sensor network that reduces the network lifetime by consuming unnecessary energy. In this paper, data collection experiment through the particulate matter sensor is carried out to confirm the spatial-temporal data redundancy and we propose permitted limit setting method for data transmission to solve this problem. In the proposed method, the data transmission permitted limit is set by using the integrated average value in the cluster. The set permitted limit reduces the redundant data of the member node and it is shows that redundant data reduction is possible even in a variable environment of collected data by resetting the permitted limit in the cluster head.

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Spatial Patterns of Forest Fires between 1991 and 2007 (1991년부터 2007년까지 산불의 공간적 특성)

  • Lee, Byung-Doo;Lee, Myung-Bo
    • Fire Science and Engineering
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    • v.23 no.1
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    • pp.15-20
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    • 2009
  • For the effective management of forest fire, understanding of regional forest fire patterns is needed. In this paper, forest fire ignition and spread characteristics were analyzed based on forest fire statistics. Fire occurrences, burned area, rate of spread, and burned area per fire between 1991 and 2007 were parameterized for the cluster analysis, which results were displayed using GIS to detect spatial patterns of forest fire. Administrative districts such as cities and counties were classified into 5 clusters by fire susceptibility. Metropolitan areas had fire characteristics that were infrequent, slow rate of spread, and small burned area. However, 4 cities and counties showing fast rate of spread, and large burned area, in the eastern regions of Taeback Mountain range, were the most susceptible areas to forest fire. The next vulnerable cities and counties were located in the West and South Coast area.

Ergodic Capacity Analysis of OFDM Transmission Channel Applied to the MIMO Antennas Considering Spatial Propagation Property (공간적 전파전파 특성을 고려한 MIMO 안테나에 적용한 OFDM 전송 채널의 에르고딕 용량 분석)

  • Kim Chang-Joong;Lee Ho-Kyoung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.3 s.106
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    • pp.267-271
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    • 2006
  • In this paper, we use the OFDM transmission channel model applied to the MIMO antennas considering spatial propagation property to evaluate and investigate the ergodic capacity of the channel. Specially, we have applied our results to 3GPP TR 25.99 V1.1.0 case 1 LOS off channel description and calculated ergodic capacity with parameters, cluster angle spread and angle of arrival(AOA). Our results show that as the cluster angle spread increase the channel capacity increase until 35 degree, but for more than 35 degree channel capacity does not improved.

A Novel Image Segmentation Method Based on Improved Intuitionistic Fuzzy C-Means Clustering Algorithm

  • Kong, Jun;Hou, Jian;Jiang, Min;Sun, Jinhua
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.6
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    • pp.3121-3143
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    • 2019
  • Segmentation plays an important role in the field of image processing and computer vision. Intuitionistic fuzzy C-means (IFCM) clustering algorithm emerged as an effective technique for image segmentation in recent years. However, standard fuzzy C-means (FCM) and IFCM algorithms are sensitive to noise and initial cluster centers, and they ignore the spatial relationship of pixels. In view of these shortcomings, an improved algorithm based on IFCM is proposed in this paper. Firstly, we propose a modified non-membership function to generate intuitionistic fuzzy set and a method of determining initial clustering centers based on grayscale features, they highlight the effect of uncertainty in intuitionistic fuzzy set and improve the robustness to noise. Secondly, an improved nonlinear kernel function is proposed to map data into kernel space to measure the distance between data and the cluster centers more accurately. Thirdly, the local spatial-gray information measure is introduced, which considers membership degree, gray features and spatial position information at the same time. Finally, we propose a new measure of intuitionistic fuzzy entropy, it takes into account fuzziness and intuition of intuitionistic fuzzy set. The experimental results show that compared with other IFCM based algorithms, the proposed algorithm has better segmentation and clustering performance.

A Study on Spatial Patterns of Traffic Accidents using GIS and Spatial Data Mining Methods: A Case Study of Kangnam-gu, Seoul (GIS와 공간 데이터마이닝을 이용한 교통사고의 공간적 패턴 분석 - 서울시 강남구를 사례로 -)

  • 이건학
    • Journal of the Korean Geographical Society
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    • v.39 no.3
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    • pp.457-472
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    • 2004
  • The purpose of this study is to analyze spatial patterns of traffic accidents and to investigate spatial relations among neighboring spatial objects by applying GIS and spatial data mining methods. This study investigated traffic accident data in Kangnam-gu, Seoul, as a case study. As a result, four clusters were emerged based on individual attributes of traffic accidents. Each cluster showed distinctive properties. In spatial associations between individual attributes of traffic accidents and neighboring spatial objects, there were many rules according to concept hierarchy and definition of spatial relations. Although all rules were not be interesting and significant, they could be a clue to investigate more.

Analysis of Population Depending on Spatial Unit for Setting Suitable Spatial Unit to Rural Planning (농촌계획 수립에 적합한 공간단위 설정을 위한 공간 단위에 따른 인구 비교 분석)

  • Lee, Jimin
    • Journal of Korean Society of Rural Planning
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    • v.25 no.3
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    • pp.1-9
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    • 2019
  • Population is important as a fundamental element of local industry and economy, and census data is essential to regional planning and policy making. Although there have been many researches on population and regional planning, there are few studies on population considering spatial unit. In this study, the population of three spatial scales were compared in order to establish the spatial unit suitable for the rural planning. The study area is Gangwon, Chungcheong-Nam, Chungcheong-Buk, Jeolla-Nam, Jeolla-Buk, Gyeonsang-Nam, Gyeonsang-Buk and Jeju province. Population were compared using statistical data analysis, GIS visualization, and spatial statistics. The mean, maximum, minimum, and variance of population were calculated and the coefficient of variation according to spatial unit was compared. The mean, maximum, minimum, and variance of population were calculated and the coefficient of variation according to spatial unit was compared. As the results, the census output area unit is difficult to interpret spatial analysis results. Administrative district unit has the limit that includes areas where the population does not live. The grid unit is well suited to the geographical characteristics but has many disadvantages of the grid with small population. Therefore, It is necessary to complement the limits of the Eup and Myeon-dong administrative district through the grid unit data.