• Proceedings of the Korean Information Science Society Conference
• /
• 2003.10b
• /
• pp.124-126
• /
• 2003

다차원 색인 기법 M-트리는 노드의 중심점과 객체간의 상대적 거리로 색인을 구성하고, 검색 공간에 포함되는 객체를 액세스하는 기법으로서 노드들은 페이지 단위로 구성되며 하위 엔트리들을 포함할 수 있는 반경, 즉 유사도 거리에 의해 노드의 영역이 표현되어진다. 그러나 이와 같은 노드의 영역 표현에 있어서 노드 색인공간의 중첩으로 인해 질의 시 검색 패스가 증가하고 이로 인해 거리계산과 디스크 입출력의 증가를 야기하는 문제를 갖는다. 본 논문에서는 M-트리에서 문제가 되고 있는 노드 색인 공간의 중첩을 최소화할 수 있는 노드 분할 정책을 제안한다. 기존의 M-트리와는 다르게 노드의 가상 중심점을 계산하여 그것을 라우팅 객체로 만들어 노드를 커버하는 영역을 최소화하고 노드 안의 엔트리를 재분배하여 밀도 높은 노드를 구성 하도록 한다. 제안된 분할 알고리즘의 효율성을 증명하기 위한 실험 결과 색인공간의 중첩이 줄고 이로 인해 거리계산과 디스크 입출력의 횟수가 줄어듦을 보였다.

• Journal of KIISE:Databases
• /
• v.30 no.6
• /
• pp.593-605
• /
• 2003

Since spatial join processing consumes much time, several algorithms have been proposed to improve spatial join performance. The M-way R-tree join (MRJ) is a join algorithm which synchronously traverses M R-trees in the M-way spatial join. In this paper, we introduce indirect predicates which do not directly come from the multi-way join conditions but are indirectly derived from them. By applying the concept of indirect predicates to MRJ, we improve the performance of MRJ. We call such a multi-way R-tree join algorithm using indirect predicates indirect predicate filtering (IPF). Through experiments using synthetic data and real data, we show that IPF significantly

• Journal of KIISE:Computing Practices and Letters
• /
• v.16 no.4
• /
• pp.442-446
• /
• 2010

In this paper we propose an indexing method supporting the browsing scheme for effective image search on large photo database. The proposed method is based on M-tree, a representative indexing scheme on matrix space. While M-tree focuses on the searching efficiency by pruning, it did not consider browsing efficiency directly. This paper proposes node selection method, node splitting method and node splitting conditions for browsing efficiency. According to test results, node cohesion and clustering precision improved 1.5 and twice the original respectively and searching speed also increased twice the original speed.

• Parasites, Hosts and Diseases
• /
• v.28 no.1
• /
• pp.25-30
• /
• 1990

The direct wet mount examination of vaginal. secretion, widely applied for the diagnosis of Trichcmonas vaginalis infection in woman patients, is rapi4 and economical, however, the sensitivity of this technique is not so high. In this study enzyme-linked immunosorbent assay (ELISA) was employed for the detection of serum anti-T. vaginalis IgG and IsM antibodies from 30 vaginal trichomoniasis patients and 30 non-infected healthy persons. The results were as follows: 1. Serum ELISA-IgG value was $0.37{\pm}0.134(Mean{\pm}S.D.)$ in vaginal trichomoniasis patients and $0.21{\pm}0.054$ in healthy controls(P<0.005), and the sensitivity and specificity of ELISA for serum IgG antibody were 70.0% and 96.7%, respectively. 2. Serum ELISA-IgM value was $0.33{\pm}0.177 (Mean{\pm}S.D.)$ in vaginal trichomonlasls patients and $0.11{\pm}0.051$ in healthy controls (p<0.005), and the sensitivity and specificity of ELISA for serum IsM antibody were 70.0% and 96.7%, respectively. 3, The ELISA-IgG values showed a significant correlation with ELISA-IgM values(r=0.77, p<0.005) , With above results, it is assumed that ELISA is a reliable method for the diagnosis of T vaginalis infection and simultaneous measurement of serum IgG and IgM with this technique is recommended.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2011.11a
• /
• pp.133-136
• /
• 2011

트리의 검색은 어플리케이션에서 흔하게 사용되는 연산중 하나이다. 하지만 대부분의 트리는 연결 리스트 기반으로 생성되며 연결 리스트 트리 구조는 데이터의 지역성을 가지기 힘들기 때문에 트리구조의 검색을 동반한 응용은 캐시메모리 사용효율의 제약으로 인해 성능상의 문제점이 존재한다. 본 논문에서는 연결 리스트 트리를 배열 기반의 트리로 변형하여 트리 검색 시 성능을 향상시킬 수 있는 방법을 제시한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2009.04a
• /
• pp.996-998
• /
• 2009

접미사 트리는 주어진 하나의 문자열의 모든 접미사를 표현하는 트리로, 문자열 처리, 압축 등 다양한 분야에서 활용된다. 접미사 트리는 문자열 집합에 대한 자료구조로 확장될 수 있는데, 이를 일반화된 접미사 트리라 부른다. 본 논문에서는 일반화된 접미사 트리를 동반적이면서 온라인으로 생성하는 문제를 다룬다. 기존의 생성 알고리즘은 정방향의 문자열이 아닌 역방향의 문자열들에 대한 일반화된 접미사 트리를 생성하여, 부자연스럽다. 본 논문에서는 정방향 문자열들의 일반화된 접미사 트리를 동반적이면서 온라인으로 생성하는 알고리즘을 제시한다.

• Journal of KIISE:Databases
• /
• v.36 no.6
• /
• pp.455-465
• /
• 2009

Suffix trees are widely used in similar sequence matching for DNA. They have several problems such as time consuming, large space usages of disks and memories and data skew, since DNA sequences are very large and do not fit in the main memory. Thus, in the paper, we present a space efficient indexing method called SENoM, allowing us to build trees without merging phases for the partitioned sub trees. The proposed method is constructed in two phases. In the first phase, we partition the suffixes of the input string based on a common variable-length prefix till the number of suffixes is smaller than a threshold. In the second phase, we construct a sub tree based on the disk using the suffix sets, and then write it to the disk. The proposed method, SENoM eliminates complex merging phases. We show experimentally that proposed method is effective as bellows. SENoM reduces the disk usage less than 35% and reduces the memory usage less than 20% compared with TRELLIS algorithm. SENoM is available to query efficiently using the prefix tree even when the length of query sequence is large.

• Journal of KIISE:Computer Systems and Theory
• /
• v.36 no.3
• /
• pp.149-157
• /
• 2009

The crossed cube, a variation of the hypercube, possesses a better topological property than the hypercube in its diameter that is about half of that of the hypercube. It has been known that an N-node complete binary tree is a subgraph of an (N+1)-node crossed cube [P. Kulasinghe and S. Bettayeb, 1995]. However, efficient embedding methods have not been known for the case that the number of nodes of the complete binary tree is greater than that of the crossed cube. In this paper, we show that an N-node complete binary tree can be embedded into an M-node crossed cube with dilation 1 and load factor [N/M], N>M$\geq$2. The dilation and load factor is optimal. Our embedding has a property that the tree nodes on the same level are evenly distributed over the crossed cube nodes. The property is especially useful when tree-structured algorithms are processed on a crossed cube in a level-by-level way.

• Electrical & Electronic Materials
• /
• v.4 no.3
• /
• pp.229-238
• /
• 1991

본 논문에서는 영상센서를 이용하여 유기절연물질내의 트리 열화현상을 측정할 수 있는 시스템에 관하여 논하였다. 기존의 육안관찰법으로서는 관측하는 것이 매우 어려웠던 트리형상의 변화를 화상처리 기술을 이용하므로서 트리발생 직후부터 관측할 수 있게 되었다. 실험결과, 화상처리장치는 최초로 발생된 트리에서 부터 그 진전상황을 즉각적으로 기록할 수가 있었으며 트리의 신장도, 열화면적 및 연속 화상처리 측면에서 트리의 진전특성을 고찰하였다.

• Journal of Soil and Groundwater Environment
• /
• v.13 no.1
• /
• pp.24-31
• /
• 2008

Sulfate reducing bacteria (SRB) is universally distributed in the sediment, especially in marine environment. SRB reduce sulfate as electron acceptor to hydrogen sulfide in anaerobic condition. Hydrogen sulfide is reducing agent enhancing the reduction of the organic and inorganic compounds. With SRB, therefore, the degradability of organic contaminants is expected to be enhanced. Ferrous iron reduced from the ferric iron which is mainly present in sediment also renders chlorinated organic compounds to be reduced state. The objectives of this study are: 1) to investigate the reduction of TCE by hydrogen sulfide generated by tht growth of SRB, 2) to estimate the reduction of TCE by ferrous iron generated due to oxidation of hydrogen sulfide, and 3) to illuminate the interaction between SRB and ferrous iron. Mixed bacteria was cultivated from the sludge of the sewage treatment plant. Increasing hydrogen sulfide and decreasing sulfate confirmed the existence of SRB in mixed culture. Although hydrogen sulfide lonely could reduce TCE, the concentration of hydrogen sulfide produced by SRB was not sufficient to reduce TCE directly. With hematite as ferric iron, hydrogen sulfide produced by SRB was consumed to reduce ferric ion to ferrous ion and ferrous iron produced by hydrogen sulfide oxidation decreased the concentration of TCE. Tests with seawater confirmed that the activity of SRB was dependent on the carbon source concentration.