초격자구조 데이타 베이스 컴퓨터에서의 분할에 기초한 병렬 결합 알고리즘

학위논문(박사) - 한국과학기술원 : 전기 및 전자공학과, 1991.2, [ vi, 108 p. ; ]The problem for improving performances of database management systems has attracted great interests during the two decades. This thesis is, especially, concerned with the problem for improving the performance of the join operation, which is one of the most frequently used and one of the most complex operations in the realtional database management systems. Two partition-based join algorithms, the sort-partitioned join and the select partitioned join algorithms, are proposed for reducing the number of secondary storage accesses in single processor computers. We further investigate for the effecient partitioning techniques and propose two improved versions of the sort-partitioned join and an improved version of the select-partitioned join. Analytic comparisons show that the two proposed partition-based join algorithms always outperforms the sort-merge join and performs better tnan the hash-partitioned join in most cases. The analyses for the proposed join algorithms are validated in practical situations by simulation experiments. The simulation experiments show that the improved version of the select-partitioned join performs best in most cases. We propose a general execution model for the paralle execution of the partition-based join algorithms on a hypercube database computer and, from the execution model, several parallel partition-based join algorithms are designed, analyzed, and compared. The hypercube database computer consists of a set of subcubes where each subcube shares a secondary storage device. The execution model consists of three phases; global partitioning phase, local partitioning phaes, and local joining phase. The partitioning schemes studied for the single processor computers are extended and applied for each execution phase of the execution model. Several promising parallel partition-based join algorithms are derived from the execution model and their preformances are analyzed in terms of computation cost, communication cost, and I/O cost. Fr...한국과학기술원 : 전기 및 전자공학과

A study on a method of structural scene matching for aerial image

학위논문(석사) - 한국과학기술원 : 전기 및 전자공학과, 1985.2, [ iii, 63, [17] p. ]한국과학기술원 : 전기 및 전자공학과

고막재생용 인조 키토산 패치

본 발명은 고막재생용 인조 키토산 패치에 관한 것으로, 구체적으로 천연고분자 물질인 키토산을 이용하여 제조한 고막재생용 스캐폴드에 관한 것이다. 본 발명의 키토산 패치는 천공된 고막의 효율적인 재생을 위해서 생체적합재료인 키토산을 이용하여 제조한 것으로서 고막천공에 따른 고막재생 수술을 대신하고 기존의 종이 패치의 단점을 극복하여 고막을 재생시키는데 유용하게 이용될 수 있을 것이다