• Proceedings of the Korean Information Science Society Conference
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• 1999.10a
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• pp.258-260
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• 1999

주기억 데이터베이스를 위한 색인 구조는 기존의 디스크 기반 데이터베이스의 색인 구조와는 고려되어야 할 사항이 다르다. 최근까지 연구된 색인 구조 중 대표적인 것은 T-트리와 T*-트리이다. 비록 T*-트리가 T-트리의 단점인 범위 질의의 비효율성을 해결하고 있지만 데이터의 삽입과 삭제가 많은 시스템에서 트리 균형을 맞추기 위한 오버헤드, 회전 연산의 수행과 후위 포인터(successor pointer)의 추가적인 오버헤드가 있다. 따라서 본 논문에서는 삽입과 삭제가 빈번한 동적 주기억 데이터베이스를 위해서 억제된 노드 생성 및 삭제 기법과 스레드 이진 트리의 특성을 이용한 보다 효율적인 색인 구조인 T2-트리를 제안한다.

• The KIPS Transactions:PartA
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• v.10A no.6
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• pp.665-670
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• 2003

In the applications like automatic masks generation for semiconductor production, a drawing consists of lots of polygons that are partitioned into trapezoids. The addition/deletion of a polygon to/from the drawing is performed through geometric operations such as insertion, deletion, and search of trapezoids. Depending on partitioning algorithm being used, a polygon can be partitioned differently in terms of shape, size, and so on. So, It's necessary to invent some comparison algorithm of sets of trapezoids in which each set represents interested parts of a drawing. This comparison algorithm, for example, may be used to verify a software program handling geometric objects consisted of trapezoids. In this paper, given k sets of trapezoids in which each set forms the regions of interest of each drawing, we present how to compare the k sets to see if all k sets represent the same geometric scene. When each input set has the same number n of trapezoids, the algorithm proposed has O(2$^{k-2}$ $n^2$(log n＋k)) time complexity. It is also shown that the algorithm suggested has the same time complexity O( $n^2$ log n) as the sweeping-based algorithm when the number k(<< n) of input sets is small. Furthermore, the proposed algorithm can be kn times faster than the sweeping-based algorithm when all the trapezoids in the k input sets are almost the same.