• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.3 s.106
• /
• pp.267-271
• /
• 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.

• Journal of the Economic Geographical Society of Korea
• /
• v.9 no.3
• /
• pp.297-317
• /
• 2006

This article is aimed to find a more successful way to build a metropolitan-wide governance for enhancing industrial cluster in South-East region, Korea. We begin a research with reviewing a current study of regional cluster and its governance. New industrial system and agglomeration changed regional growth theory and urban system. In traditional system, a central city dominated economy of the metropolitan area. However, with development of new transportation and communication technology, a central city lost their superiority to suburban cities. In other words, growing competition between central and suburban cities changed traditional concentration and diffusion theory of urbanization which dominated urban geography for last decades. Next, current situation of development of industrial cluster in South-East region is examined to suggest policy for more competitiveness. South-East region has grown as the most prominent cluster of mechanical engineering and metal industry in Korea since the late 1970s. In the form of agglomeration and network of a specific and its related industry, South-East region has formed a linear industrial belt along with the inter-regional South Coast Highway and contain about ten industrial cities. Accompanying with this growing South-East region, a problem has risen from geographic mismatch between metropolitan-wide industrial cluster and its administrative boundary. Since industrial cluster has no specific administrative boundary, adequate government support for developing industrial cluster has not been provided. Responding to the problem, academics and policy makers maintain need in establishing a metropolitan-wide governance for supporting a cluster. At the end, this paper provides some implication to planners and policy makers.

• Journal of the Economic Geographical Society of Korea
• /
• v.4 no.2
• /
• pp.79-96
• /
• 2001

This paper introduces a new type of industrial cluster developed at the CBD of Seoul. Conventionally, clusters are said to be consisted of hi-tech, often If activities, manufacturing industries or artisan craft industries with increasing vertical integration and performance usually supported by venture capitals and favorable business infrastructure, not to mention governments', be it central or local, incentive plans. The study area, Cheonggyechon region has long been a traditional CBD frame of Seoul, Korea, being troubled by deterioration, traffic jams, and environmental degradation as most inner cities experience. Recently. this region has transformed to the most dynamic and productive area not by IT industries but by apparel and fashion activities. The study of the developmental trajectory and key characteristics for this kind of industrial cluster can give us insight both for the transition of inner city and for the cluster theory. This Paper firstly briefly Profiles the growth of the Cheonggyechon region over the past decade. It then shows the current spatial and business structure of the new industrial cluster, focusing on the fact that transactions costs are reduced, the creation and flow of information improves. and the local institutions are prone to be most responsive to the new cluster's specialized needs. The third section presents the key components of the customized production-distribution-shopping cluster development process, emphasizing the localized networking. social capital, spontaneous institutionalization of associational economic climate, and cultural economy based on place-specific inertia. The paper concludes with some comments about the prospects and perils of the new industrial cluster of Seoul.

• Journal of the Economic Geographical Society of Korea
• /
• v.11 no.3
• /
• pp.302-318
• /
• 2008

As socio-economic paradigms have been moving towards the knowledge-based capitalism from the industrial capitalism, it is obvious that research on industrial agglomeration and regional innovation has been explosively increased. However, there is a contradictory tendency that the terms and concepts, which are related to industrial agglomeration, have became less clear and more fuzzy. In this sense, this paper attempts to tackle and reconsider the concept, typology and theories of agglomeration and (or) cluster in economic geography. The main claims are as follows. Firstly, the terms and concepts related to industrial agglomeration and cluster need to be clear. It seems to be that cluster is received as an umbrella concept of agglomerations all-embracing the varieties of a geographical concentration of industry. However, the authors claim that the cluster concept should be part of the diverse types of industrial agglomeration. Secondly, the tendency of a less clear definition on agglomeration and cluster could make it difficult to identify the types of agglomeration being in the forms of diversity. Such a tendency would result in a misguided understanding and interpretation of a typology of agglomeration. Finally and most importantly, as perspectives or theories that are associated with industrial agglomeration and cluster show increasingly a propensity of convergence, it is problematic that related theories and perspectives lose their own identity and distinctiveness.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.10
• /
• pp.1180-1187
• /
• 2012

In this paper, joint transmission space division multiple access(JT-SDMA) scheme is proposed to mitigate inter-cell interference(ICI) in cooperative wireless communications system with limited feedback. We propose a systematic design method for a codebook consisting of a finite number of unitary matrices suitable for network multiple-input multiple-output( MIMO) channel characteristics. A centralized cluster scheduling scheme is proposed to both mitigate ICI and maximizes multiuser diversity gain with limited feedback. It is shown that the proposed JT-SDMA scheme outperforms a existing coordinated SDMA scheme even in wireless network environments where sufficient multiuser diversity order can not be provided through efficient ICI mitigation.

• KIPS Transactions on Software and Data Engineering
• /
• v.3 no.6
• /
• pp.215-218
• /
• 2014

In hashing-based methods for approximate nearest neighbors(ANN) search, by mapping data points to k-bit binary codes, nearest neighbors are searched in a binary embedding space. In this paper, we present a hashing method using a PCA-based clustering method, Principal Direction Divisive Partitioning(PDDP). PDDP is a clustering method which repeatedly partitions the cluster with the largest variance into two clusters by using the first principal direction. The proposed hashing method utilizes the first principal direction as a projective direction for binary coding. Experimental results demonstrate that the proposed method is competitive compared with other hashing methods.

• Annual Conference of KIPS
• /
• 2005.05a
• /
• pp.39-42
• /
• 2005

공간 데이터 웨어하우스 구축기는 소스 데이터의 변경 사항을 일괄처리의 형태로 공간 데이터 웨어하우스에 적재한다. 또한, 공간 데이터 웨어하우스 서버는 사용자의 질의에 빠른 응답을 하기위해 적재된 데이터로 색인을 구축한다. 색인을 구성하는 기존 기법으로는 벌크 삽입 기법 및 색인 전송 기법이 있다. 벌크 삽입 기법은 색인을 구성하기 위한 클러스터링 비용이 필요하며 검색 성능도 떨어진다. 또한, 색인 전송 기법은 주기적인 소스 데이터의 변경을 지원하지 않는다는 문제점이 있다. 본 논문에서는 이와 같은 문제점을 해결하기 위해 공간 데이터 웨어하우스에서 부분 색인 전송을 이용한 효율적인 색인 재구성 기법을 제안한다. 제안 기법은 구축기에서 색인의 구조에 맞게 클러스터링된 클러스터들을 부분 색인으로 구성하여 페이지 단위로 전송한다. 공간 데이터 웨어하우스 서버에서는 전송된 부분 색인의 물리적 사상 문제를 해결하기 위해 물리적으로 연속된 공간을 예약하고 예약된 공간에 부분 색인을 기록한다. 기록된 부분 색인은 공간 데이터 웨어하우스 서버에 있던 기존 색인에 삽입된다. 부분 색인이 기존 색인에 직접 삽입됨으로써 색인 재구성을 위한 검색, 분할, 재조정 비용은 최소가 된다.

• Journal of KIISE:Databases
• /
• v.28 no.1
• /
• pp.69-85
• /
• 2001

공간 데이터베이스에서 효율적으로 공간 질의를 처리하기 위해서는 클러스터링을 통해서 이스크 접근 비용을 줄이는 것이 필요하다. 이 논문은 공간 지역성에 기반을 둔 여러 가지 클러스터링 알고리즘을 제안하고 실험을 통해 제안한 클러스터링 알고리즘의 성능을 평가하였다. 이 논문에서 제안하는 클러스터링 알고리즘은 객체 클러스터링 알고리즘과 셀 클러스터링 알고리즘으로 나뉜다. 객체 클러스터링 알고리즘은 정규 준할 공간 색인 구조에서 영역 분할 선과 겹치는 객체들의 저장 위치를 결정하는데 사용된다. 셀 클러스터링 알고리즘은 클러스터를 만들기 위해 정규 분할된 영역들을 그룹화하는데 사용된다. 실험결과 객체 클러스터링 알고리즘에서는 객체간의 거리를 이용한 경우에 대체로 좋은 성능을 보였지만, 버퍼 크기가 커지거나 데이터가 희박한 영역의 질의에 있어서는 알고리즘 별로 성능의 차이는 거의 없었다. 셀 클러스터링 알고리즘에 대한 실험에서는 이 논문에서 제안한 클러스터링 알고리즘은 N-순서화 기법에 의한 클러스터링 알고리즘에 비해 우수한 성능을 보였다. 특히 중복 참조도를 이용한 경우와 셀의 무게 중심간 거리를 이용한 방법이 가장 우수하였다.

• Annual Conference of KIPS
• /
• 2021.11a
• /
• pp.948-951
• /
• 2021

본 논문에서는 직육면체 형태의 실내 공간에서 다중 개체 영역을 검출하는 방법을 제안한다. 평면 검출 알고리즘은 평면성을 띄지 않거나 관측이 미흡한 영역에 대해 기하 정보를 검출할 수 없다. 이로 인해 장애물과 같은 개체의 영역을 파악할 수 없는 한계점이 있다. 제안 방법은 유클리드 클러스터링을 기반으로 군집화를 수행하고, 클러스터의 간소화를 통해 다중 개체 영역을 검출한다. 제안 방법은 직육면체 공간의 내부표면을 활용해 직육면체 공간과 좌표계를 공유하는 주요 개체들의 영역을 다량으로 검출한다. 제안 방법은 실험을 통해 다중 개체 영역이 적합하게 검출되었음을 보인다.

• Journal of the Korean Geographical Society
• /
• v.51 no.6
• /
• pp.853-871
• /
• 2016

The interest in the prevention of sex crimes and social secure is growing as the number of cases by sexual offences becomes higher. Although various punishable ways have been introduced so far, increasing sex crime is still going on. Thus, effectiveness of legal systems for preventing crimes is questionable. More recently, the approach for environmental criminology has been paid attention for reducing criminal opportunities through environmental design and management of crimes. This study attempts to look over the spatial distribution of sexual crimes in the context of environmental criminology, and examine the correlation between regional environmental factors and the occurrence of sexual crimes empirically. To do this, we visualized the map for sex crimes at the macro-scale and explored the spatial distribution of sexual crimes and spatial clusters based on various spatial statistics using sex crime data published online by the ministry of gender equality and family. Also, we derived the environmental characteristics of sexual crimes by multivariate regression analysis on a large number of explanatory variables of regional environment. Our results will help to understand the current situation and spatial aspects of sex crimes in the nation more realistically. Further, it is respected that our results might be useful basic information for establishing regional policies and plans for the prevention of the sexual crime and enhanced public policing.