• Journal of KIISE:Computing Practices and Letters
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• v.16 no.7
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• pp.799-803
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• 2010

The KDB-tree is a traditional indexing scheme for retrieving multidimensional data. Much research for KDB-tree family frequently addresses the low storage utilization and insufficient retrieval performance as their two bottlenecks. The bottlenecks occur due to a number of unnecessary splits caused by data insertion orders and data skewness. In this paper, we propose a novel index structure, called as $KDB_{CS}^+$-tree, to process skewed data efficiently and improve the retrieval performance. The $KDB_{CS}^+$-tree increases the number of fan-outs by exploiting bit-vectors for representing splitting information and pointer elimination. It also improves the storage utilization by representing entries as a hierarchical structure in each internal node.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.19-21
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• 2002

최근 이동통신 및 GPS 기술의 발달로 위치기반서비스 요구가 점점 증가하고 있고, 대용량의 위치데이터가 저장되는 위치기반서비스의 구현을 위한 이동체외 저장 및 검색에 관한 연구가 활발하다. 이동체의 위치 정보를 점으로 모델링하여 색인 할 경우 KDB-Tree의 성능이 우수하다. 그러나 KDB-Tree는 시공간에서의 이동체 위치데이터 색인을 고려할 경우 시간 도메인의 특성으로 인해 성능 저하의 문제를 발생시킨다. 본 논문에서는 이동체 위치데이터의 색인을 위한 KDB-Tree의 사용에서 시간 도메인의 특성을 반영한 분할 도메인 선정 방법과 분할 정책을 제시한다. 새로운 분할 정책은 색인의 공간활용도를 높이고 색인의 크기를 작게 하여 검색의 성능을 높인 최근 시간 분할 기법과 LD(Last Division) 분할 정책이다. 본 논문에서는 KDB-Tree의 변경된 분할 정책을 구현하고 성능평가론 수행한다. 이 성능 평가 실험을 통해서 변경된 분할 정책을 사용한 KDB-Tree에서 공간활용도가 높고 검색 성능이 우수함을 보인다.

• Journal of KIISE:Databases
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• v.34 no.4
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• pp.328-342
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• 2007

We propose a new cache conscious indexing structure for processing frequently updated data efficiently. Our proposed index structure is based on a KDB-Tree, one of the representative index structures based on space partitioning techniques. In this paper, we propose a data compression technique and a pointer elimination technique to increase the utilization of a cache line. To show our proposed index structure's superiority, we compare our index structure with variants of the CR-tree(e.g. the FF CR-tree and the SE CR-tree) in a variety of environments. As a result, our experimental results show that the proposed index structure achieves about 85%, 97%, and 86% performance improvements over the existing index structures in terms of insertion, update and cache-utilization, respectively.

• Journal of KIISE:Databases
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• v.33 no.4
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• pp.396-408
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• 2006

Moving object databases manage a large amount of past location data which are accumulated as the time goes. To retrieve fast the past location of moving objects, we need index structures which consider features of moving objects. The KDB-tree has a good performance in processing range queries. Although we use the KDB-tree as an index structure for moving object databases, there has an over-split problem in the spatial domain since the feature of moving object databases is to increase the time domain. Because the over-split problem reduces spatial regions in the MBR of nodes inverse proportion to the number of splits, there has a problem that the cost for processing spatial-temporal range queries is increased. In this paper, we propose the dynamic split strategy of the KDB-tree to process efficiently the spatial-temporal range queries. The dynamic split strategy uses the space priority splitting method for choosing the split domain, the recent time splitting policy for splitting a point page to maximize the space utilization, and the last division policy for splitting a region page. We compare the performance of proposed dynamic split strategy with the 3DR-tree, the MV3R-tree, and the KDB-tree. In our performance study for range queries, the number of node access in the MKDB-tree is average 30% less than compared index structures.

• Journal of KIISE:Databases
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• v.31 no.6
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• pp.624-640
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• 2004

Recently, with the rapid development of location-based techniques, index structures to efficiently manage moving objects have been required. In this paper, we propose a new spatio-temporal index structure that supports a future position retrieval and minimizes a update cost. The proposed index structure combines an assistant index structure that directly accesses current positions of moving objects with KDB-tree that is a space partitioning access method. The internal node in our proposed index structure keeps time parameters in order to support the future position retrieval and to minimize a update cost. Moreover, we propose new update and split methods to maximize the space utilization and the search performance. We perform various experiments to show that our proposed index structure outperforms the existing index structure.

• 해운
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• s.102
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• pp.8-19
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• 2013

현재 해운시장은 유럽 재정위기 장기화 신흥국 실물경기 둔화 확대 등으로 인해 회복이 지연되고 있으며, 주요 해운시황 예측기관들은 시장 회복시기를 2014년~2015년 이후로 예상되고 있다. 2013년 해운시황은 전년에 비해 소폭 개선될 전망이나 공급과잉 부담으로 2015년 이후 L자형의 완만한 회복세를 보일 전망이다. 또한, 시황 회복 시 선종별 상위선사들을 중심으로 수익이 집중화될 가능성이 언급되고 있으며, 상위 선사들을 중심으로 승자독식 체제가 형성이 우려되고 있다. 다음은 KDB산업은행 경제연구소에서 발표한 "컨테이너선 시장의 변화요인 점검 및 향후 전망"의 주요 내용을 요약 정리한 것이다.

• Journal of Physiology & Pathology in Korean Medicine
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• v.28 no.4
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• pp.371-378
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• 2014

This study was designed to investigate the antihyperlipidemic activity of aqueous extracts of Kyeongokgo (KOG), Kyeongokgo Dansambang (KDB), and Kyeongokgo Gamibang (KGB) on the hyperlipidemic rats induced by high-fat diet. The animals were divided into 4 groups of the hyperlipidemic control group, the KOG-fed group, the KDB-fed group and the KGB-fed group, and received oral administration of each prescription with diet for a period of six weeks. The changes in the body weight, the amount of food intake, the liver weight, the epididymal fat weight, and the plasma levels of total cholesterol, triglyceride, HDL-cholesterol and LDL-cholesterol were measured. In all experimental groups, the weight of liver and epididymal fat decreased significantly. There was a significant decrease in the amount of food intake, the weight of liver and epididymal fat, the plasma level of total cholesterol, and HDL-cholesterol in the KDB-fed and the KGB-fed groups. In addition, KGB-fed group represented a significant decrease in the triglyceride. These results suggest that the aqueous extracts of Kyeongokgo Dansambang and Kyeongokgo Gamibang have a good antihyperlipidemic activity and a potential to treat hyperlipidemia.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2001.05a
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• pp.185-199
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• 2001

• Journal of the Korean Society for Library and Information Science
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• v.40 no.2
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• pp.175-194
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• 2006

A common user interface system, a subset of library portal software products was evaluated in terms of eight broader categories; searching, user interaction; customization; authentication; design; database communication protocols; after sale support; and software platforms supported. As a result, Muse search ENCompass, MetaLib were the three highest scoring common user interface software products. and KDB metasearch in domestic area was the highest scoring products.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.1
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• pp.88-93
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• 2001

기존의 데이터베이스 검색시스템은 사용자의 검색 조건에 정확히 일치하는 데이터가 데이터베이스 내에 존재할 경우에만 사용자에게 해당 데이터를 제공할 수 있고, 사용자의 검색조건을 정확히 만족하는 데이터가 없을 경우에는 적절한 데이터를 제공할 수 없는 문제점이 있다. 이러한 문제를 해결하기 위하여 본 논문에서는 FCM의 클러스터증가 및 재초기화 알고리즘을 제안하였고, FCM을 이용하여 데이터베이스 내의 데이터로부터 구축된 지식기반 데이터베이스(KDB)와 구축된 이미지 데이터베이스와 연동을 통하여 사용자의 요구에 가장 근접한 데이터를 제시해 주는 검색시스템을 제안하였다. 본 연구에서 제안된 수법을 우체국의 우편주문안내책자를 이용한 선물고르기 DB 검색 시스템에 적용하여 그 유효성을 확인하였다.