• Journal of KIISE:Software and Applications
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• v.26 no.1
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• pp.16-24
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• 1999

본 논문에서는 병렬 DBMS를 사용하는 데이터 웨어하우스의 성능을 개선하기 위한 새로운 다차원 데이터 분할 기법을 제안한다. 데이터 웨어하우스는 많은 양의 데이터를 저장하는 대용량 데이터베이스이며 분석적인 정보를 얻기 위한 다차원 범위 질의가 대부분을 차지한다. 단일 차원분할 기법으로는 다차원 질의를 효과적으로 처리하기 어렵고 기존의 다차원 분할 기법은 임의의 알 수 없는 분포를 가진 데이터에 대해 균등한 분할을 보장하기 어렵다. 본 논문에서는 hB-tree 구조를 이용하여 균등한 분할을 보장하는 다차원 분할 기법을 제안하고 그 성능을 측정하기 위한 시뮬레이터 결과를 보인다. 시뮬레이션에서 hB-tree 분할 기법은 균등 분포뿐만 아니라 비균등 분포 데이터 집합에 대해서도 균등한 분할을 보인다.

• Spatial Information Research
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• v.19 no.2
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• pp.47-56
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• 2011

Typical tree-based spatial index structures are divided into a data-partitioning index structure such as R-Tree and a space-partitioning index structure such as KD-Tree. In recent years, researches on hybrid index structures combining advantages of these index structures have been performed extensively. However, because the split boundary extension of the node to which a new spatial object is inserted may extend split boundaries of other neighbor nodes in existing researches, overlaps between nodes are increased and the query processing cost is raised. In this paper, we propose a hybrid index structure, called SQR-Tree that can support efficient processing of spatial queries to solve these problems. SQR-Tree is a combination of SQ-Tree(Spatial Quad- Tree) which is an extended Quad-Tree to process non-size spatial objects and R-Tree which actually stores spatial objects associated with each leaf node of SQ-Tree. Because each SQR-Tree node has an MBR containing sub-nodes, the split boundary of a node will be extended independently and overlaps between nodes can be reduced. In addition, a spatial object is inserted into R-Tree in each split data space and SQ-Tree is used to identify each split data space. Since only R-Trees of SQR-Tree in the query area are accessed to process a spatial query, query processing cost can be reduced. Finally, we proved superiority of SQR-Tree through experiments.

• Annual Conference on Human and Language Technology
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• 2001.10d
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• pp.422-427
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• 2001

질의어 변환 방법은 다국어 정보검색을 위한 방법중에 효율적인 방법이다. 양질의 질의어 변환을 위해서, 사전, 온톨로지, 병렬 코퍼스 통과 같은 자연언어 자원이 필요하다. 이러한 자연언어 자원은 양질로 대량으로 구축하려면 많은 비용이 튼다는 단점이 있다. 본 논문에서는 한영 질의어 변환에 적용할 수 있는 공통 중간개념 구축방법을 제안한다. 공통 중간개념은 동사들의 축으로 이루어지며, 통사들은 기본동사들의 조합으로 표현한수 있다고 가정한다. 공통 중간개념은 적은 자연언어 자원을 효율적으로 이용할 수 있도록 한다. 본 논문에서는 기본 동사 축을 특이값 분해(singular value decomposition) 방법으로 구하고, 그 기본 동사 축을 이용해서 질의어 변환하는 방법을 보여준다.

• Korean Journal of Microbiology
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• v.33 no.1
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• pp.50-54
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• 1997

이 글에서는 호수생태계에서 일어나는 변화 중 .betha.-glucosidase 활성도를 중심으로 생화학적인 분석과정을 통하여 유기물질의 분해, 생성, 소비등에 대한 과정을 설명하고자 한다. .betha.-glucosidase효소는 비교적 기질특이성이 넓고, glucose, celluhexose, carboxy-methylcellulose등의 .betha.고리를 가수분해시켜 monomer로 분해시키는 효소로서 수환경에서는 매우 중요하다. 즉 cellobiohydrolase에 의해 분해된 oligomer나 dimer를 세균의 세포막을 통과할 수 있는 크기로 분해시키는 효소이고, 이 효소의 분해 산물인 포도당은 세균에 의하여 바로 이용되고, catabolite inhibitor로 작용하므로, 이 효소 활성도의 높고 낮음은 수중생태계에서 탄소의 흐름과 세균 군집의 성장을 이해하는데 매우 중요하다(3).

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.4
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• pp.412-429
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• 2008

As the amount of electronic documents increases rapidly with the growth of the Internet, a parallel search engine capable of handling a large number of documents are becoming ever important. To implement a parallel search engine, we need to partition the inverted index and search through the partitioned index in parallel. There are two methods of partitioning the inverted index: 1) document-identifier based partitioning and 2) keyword-identifier based partitioning. However, each method alone has the following drawbacks. The former is convenient in inserting documents and has high throughput, but has poor performance for top h query processing. The latter has good performance for top-k query processing, but is inconvenient in inserting documents and has low throughput. In this paper, we propose a hybrid partitioning method to compensate for the drawback of each method. We design and implement a parallel search engine that supports the hybrid partitioning method using the Odysseus DBMS tightly coupled with information retrieval capability. We first introduce the architecture of the parallel search engine-Odysseus/parallel-OOSQL. We then show the effectiveness of the proposed system through systematic experiments. The experimental results show that the query processing time of the document-identifier based partitioning method is approximately inversely proportional to the number of blocks in the partition of the inverted index. The results also show that the keyword-identifier based partitioning method has good performance in top-k query processing. The proposed parallel search engine can be optimized for performance by customizing the methods of partitioning the inverted index according to the application environment. The Odysseus/parallel OOSQL parallel search engine is capable of indexing, storing, and querying 100 million web documents per node or tens of billions of web documents for the entire system.

• Journal of dental hygiene science
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• v.12 no.2
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• pp.171-179
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• 2012

The aim of this study was to analyze the factors related to whole saliva flow and the xerostomia for the ground use of the materials in developing oral health improvement program and life quality improvement program. So, this study performed a questionnaire survey, targeting at 160 adults, older than 40 years, living in Gyeonggi and Incheon provinces from January to February 2011 and measured unstimulated salivary flow rate and stimulated salivary flow rate. The results are as followings. The group of participants who took gums and candies to relieve oral dryness had low stimulated whole saliva flow. The group of participants who graduated from middle schools, who separated by death, who were not healthy with menopause, and who recognized periodontal disease symptoms and tongue burning sensation recognized more symptoms of dry mouth than others. In addition, the group of participants who were not satisfied with life so much, who couldn't feel the meaning of life, and who recognized negative feelings frequently recognized symptoms of dry mouth more. Women, the group of participants who graduated from middle schools, who suffered from depressive symptoms, and who recognized halitosis had low unstimulated whole saliva flow. The group of participants who graduated from middle schools, who were not satisfied with life so much, who couldn't feel the meaning of life, and who were not satisfied with themselves had low stimulated saliva flow.

• Restorative Dentistry and Endodontics
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• v.34 no.5
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• pp.406-414
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• 2009

The purpose of this study was to examine the effect of hydrogen peroxide at different application time and concentrations on the microtensile bond strength of resin restorations to the deep and the pulp chamber dentin. A conventional endodontic access cavity was prepared in each tooth, and then the teeth were randomly divided into 1 control group and 4 experimental groups as follows: Group 1, non treated; Group 2, with 20% Hydrogen peroxide ($H_2O_2$); Group 3, with 10% $H_2O_2$; Group 4, with 5% $H_2O_2$; Group 5, with 2.5% $H_2O_2$; the teeth of all groups except group 1 were treated for 20, 10, and 5min. The treated teeth were filled using a Superbond C&B (Sun medical Co., Shiga, Japan). Thereafter, the specimens were stored in distilled water at $37^{\circ}C$ for 24-hours and then sectioned into the deep and the chamber dentin. The microtensile bond strength values of each group were analyzed by 3-way ANOVA and Tukey post hoc test(p < 0.05). In this study, the microtensile bond strength of the deep dentin (D1) was significantly greater than that of the pulp chamber dentin (D2) in the all groups tested. The average of microtensile bond strength was decreased as the concentration and the application time of $H_2O_2$ were increased. Analysis showed significant correlation effect not only between the depth of the dentin and the concentration of $H_2O_2$ but also between the concentration of H202 and the application time(p < 0.05), while no significant difference existed among these three variables(p > 0.05). The higher $H_2O_2$ concentration, the more opened dentinal tubules under a scanning electron microscope(SEM) examination.

• Journal of the Korean Geotechnical Society
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• v.29 no.10
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• pp.29-37
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• 2013

Organic soils are widely distributed at Youngdong areas in Kangwon prefecture and Jeonbuk area. Such organic soils usually consist of undecomposed fiber materials. It is difficult to exactly measure the water content of such organic soils because some organic materials may decompose at $110^{\circ}C$ in drying oven. In this study, both drying oven and microwave oven methods are used to measure the water content of organic soils. Three different levels of oven temperature, $60^{\circ}C$, $80^{\circ}C$, and the standard temperature of $110^{\circ}C$, were used to measure the water content of organic soils in the 1st, 2nd, and 3rd day. The water content by microwave oven was measured for two different sample masses (30, 60 g) with five different measuring times (3, 6, 9, 12, 15 min.). As the temperature increased, the water content of organic soils increased due to the decomposition of organic materials in soils. The water content of some soils increased up to 2 times as the temperature was increased from $60^{\circ}C$ to $110^{\circ}C$. However, the water content was not changed after the 1st day, regardless of drying oven temperature and soil types. The water content by microwave oven became constant after 12 min. for the 30 g sample and 15 min. for the 60 g sample used. The measured water content by microwave oven was similar to that measured by drying oven at $60^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.4
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• pp.354-362
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• 1991

To investigate nutritional and biochemical values of buckwheat, amino acids and minerals in buckwheat harvested from Kangweon-do were analysed. Mixed flour between buckwheat and wheat were made to be used for buckwheat noodle and were also analysed minerals and major nutrients in composite flours. When three different levels of flour mix were compared, major nutrients were about same among those mixes but minerals were higher by adding more buckwheat flour, especially by adding more imported buckwheat flour. From this mixed flour, 9 minerals and 16 amino acids including 9 essential amino acids were analysed. Contents of selenium, sodium and magnessium were very high in buckwheat flour, Therefore, nutritional value of domestic buckwheat was highly evaluated. BAP method was used to determine the change of gelatinization in the noodles prepared by extruder at 8$0^{\circ}C$, and in the noodles during freeze drying and refrigeration. 70% of gelatinization was done during noolding process and retrogradation was severe during refrigeration.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.84-91
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• 2002

The purpose of study was to assess the influence of acidic drinks on the erosion of tooth enamel and the effect of fluoridated saliva on the remineralization. Twenty five drinks were sampled. The erosive potential and remineralizing effect were measured by the tooth surface microhardness test. The pH of most drinks were below pH 5.5. Reduction rates of enamel surface hardness by the flavored carbonated drink were 16.90%, 25.11%, 35.10%, and 41.62% after 5, 10, 30, and 60 minutes of demineralization, and recovery rates by remineralizaing solution were 61.52%, 67.96%, 72.13% and 75.93% after 1, 24, 48, and 72 hours of remineralization, respectively. The results suggest that the most drinks in the markets have the potential to erode the teeth and that erosion occurs fast but remineralization proceeds slowly.