• Proceedings of the SCSK Conference
• /
• 1999.10a
• /
• pp.17-41
• /
• 1999

Manuka oil sometime named New Zealand's tea tree oil is soluble in oil and come from nature. The $\alpha$-pinene extracted from Manuka oil and R-limonene which is one of the component of extracted Citrex from Grapefruit were used to estimate the antimicrobial activity and to improve the capability of antiseptic. Disk diffusion and broth dilution methods were used to measure the antimicrobial activity Escherichia coli which is gram-negative bacteria and Staphylococcus aureus which is gram-positive bacteria were used as strain. The antimicrobial activity of Manuka oil and $\alpha$-pinene for Escherichia coli, Staphylococcus aureus is similar when the concentration of Manuka oil and $\alpha$-pinene is 10${mu}ell$. However, Antimicrobial activity of Manuka oil for EscherEchta coli, Staphylococcus aureus is better than that of $\alpha$-pinene when the concentration of Manuka oil and $\alpha$-pinene is low. Antimicrobial activity of Citrex is superior to that of R-limonene. The proper ratio of Maunka oil and Citrex can Improve the antimicrobial activity. The proper ratio obtained from studies was 75% of Maunka oil and 25% Citrex for Escherichia coli, 25% of Maunka oil and 75% Citrex for Staphylococcus aureus.

• Journal of Applied Reliability
• /
• v.12 no.1
• /
• pp.35-46
• /
• 2012

Wood pellet is one of biomass energy fuels, which is produced by compressing woody biomass such as sawdust, planer shavings, and whole-tree removal or tree tops and branches leftover after logging into cylindrical form. Latterly much attention has been paid to wood pellet boiler which is suitable for use at various scales in domestic and industrial furnaces for heat production to replace conventional fossil fuel energy sources since the use of wood pellet that is carbon neutral can alleviate global warming. This study presents the result of developing a high efficiency wood pellet boiler with 55MJ/h capacity. Efficiency has been improved by using a rotating disk burner with a shorter screw feeder. Special attention has been paid to the improvement of the safety of the wood pellet boiler from backfire by adopting a double protecting system composed of a shutter and an air curtain. The result shows that the efficiencies of the wood pellet boiler are 97.2% and 89.2% based on lower and higher heating values, respectively, at 15.1kW of heating output.

• International Journal of Clinical Preventive Dentistry
• /
• v.14 no.4
• /
• pp.216-221
• /
• 2018

Objective: In this study, we tried to investigate the antimicrobial activity of natural herbaceous plant-derived essential oils against oral disease-causing bacterial strains and establish the scientific evidences to apply them to the dentifrice, mouthwash, and other uses. Methods: We used the disk diffusion method with 23 types of 100% natural essential oils to verify the antimicrobial effect against Streptococcus mutans, Porphyromonas gingivalis, and Lactobacillus rhamnosus. After adhering to the surface of the plate culture medium, $20{\mu}l$ of the essential oil was prepared, and the diameter of the transparent ring was measured after incubation for 24 hours. All the experiments were repeated three times. Results: Among 23 types of oils, 13 were effective against all three strains: myrrh, ginger, basil, carrot seed, tea tree, patchouli, ylang ylang, cypress, lemongrass, cinnamon, peppermint, lavender, and eucalryptus. Seventeen oils were effective against S. mutans, and myrrh, basil, and carrot seed showed high antimicrobial activity. Eighteen oils were effective against P. gingivalis, and tea tree, carrot seed, and cinnamons showed high antimicrobial activity. Sixteen oils were effective against L. rhamnosus, and carrot seed and peppermint cinnamon showed high antimicrobial activity. Conclusion: Consequently, 13 essential oils showed the antimicrobial activity against three bacterial strains, which indicates these essential oils might be used as the effective materials to suppress the growth of oral-disease inducing microorganisms. Moreover, essential oils that have been analyzed activities in this study will be mixed up within the constant range and analyzed their antimicrobial effects to examine the synergistic activity among them.

• Journal of Korea Foresty Energy
• /
• v.20 no.2
• /
• pp.69-80
• /
• 2001

Larix kaemferi Carr. is one of main timber species in Korea that could be found in plantations and growing stands on all over the country The proper practice of thinning is one of very important techiques in silviculture, which greatly affects the quality and size of timber produced. Proper thinning period is considered to be important for maintaining stand growth before competition initiated. To investigate suitable thinning period, this study investigates the volume and radial growths of Larix kaemferi plantation in Mt. Worak located in the central part of Korea. The main findings and conclusions obtained from this study were as follow ; (1) The tree height curve equation for Larix kaemferi in Mt. Worak was calculated H=4.25783+0.80024D(H=Tree height, D=DBH). (2) To estimate tree volume for Larix kaemferi by DBH and tree height or only by DBH, regression equations were calculated as V=0.00147-0.002095D-0.000211H+0.00015D.H++$0.000744D^2$+$0.000008H^2$(V=Volume(($m^3$), H=Tree height(m), D=DBH(cm)), V=0.0000794-0.000512D+$0.000826D^2$. (3) The criteria of estimating thinning time of Larix kaemferi are the age when maximum tree height-MAI(mean annual increment) obtained and the age when annual DBH increments of dead trees decrease to below average. (4) The age of maximum tree height MAI was not significantly correlated with stocking. Therefore, it can not be used as a criterion for estimating thinning time of Larix kaemferi (5) The estimated thinning time equation of Larix kaemferi was obtained by regression analysis of the disk section collected from dead trees. The obtained equation is Y=0.2825+0.01752X(Y=Desirable thinning age, X=the sum total of nearest 4-trees interval(cm)). (6) General estimated thinning age of Larix kaemferi, which planted 3,086 stocks/ha, is concluded as 12 to 14 year.

• Journal of Korean Society of Forest Science
• /
• v.88 no.4
• /
• pp.429-437
• /
• 1999

Heavy metals(Cd, Cu, Pb and Zn) in tree rings of P. thunbergii growing at Onsan Industrial Complex of air polluted area were analyzed to study the condition of heavy metal pollution. The tree ring width began to decrease after operation of factories and decreased abruptly at Onsan Industrial Complex after 1991. Cd contents in tree rings showed 119.4ppb to 867.0ppb level and suddenly increased after 1991. Cu contents showed 309.5ppb to 3686.8ppb, and Pb contents 911.33ppb to 7997.1ppb and fluctuations of those were high after operation of factories. Zn contents showed the highest level of 3528.7ppb to 23826.7ppb and largely ascended after 1960, and increased suddenly after 1992, as compared to former tendency. On the other hand, heavy metal contents in tree rings of P. thunbergii at Gosung of non-air polluted area were far lower than Onsan I. C., and there was a wide difference between both areas after 1990. On the heavy metal contents accumulated in bark of P. thunbergii of both areas, it was higher to 10 times in Cd, 1,000 times in Cu, 285 times in Pb and 133 times in Zn contents at Onsan than at Gosung. In the heavy metal analysis for circle plate and cores, heavy metal contents in cores were generally higher than those in disk and Pb contents showed specially high difference, but pattern of variation by tree age showed a similar tendency.

• Proceedings of the IEEK Conference
• /
• 2003.07c
• /
• pp.2561-2564
• /
• 2003

Data mining is an effective method of the discovery of useful information such as rules and previously unknown patterns existing in large databases. The discovery of association rules is an important data mining problem. We have developed a new parallel mining called Distributed Frequent Pattern Tree (abbreviated by DFPT) algorithm on a distributed shared nothing parallel system to detect association rules. DFPT algorithm is devised for parallel execution of the FP-growth algorithm. It needs only two full disk data scanning of the database by eliminating the need for generating the candidate items. We have achieved good workload balancing throughout the mining process by distributing the work equally to all processors. We implemented the algorithm on a PC cluster system, and observed that the algorithm outperformed the Improved Count Distribution scheme.

• The Transactions of the Korea Information Processing Society
• /
• v.5 no.5
• /
• pp.1109-1118
• /
• 1998

Recently, much attention has been focused on video databases. Video documents also have a hierarchical logical structure like text documents. By exploiting this structure using structure queries, users can obtain greater benefits than by using only content queries. In order to process structure queries efficiently, an index structure supporting fast video element access must be provided. However, there has been little attention to the index structure for video documents. In this paper, we present a tree-structured video document model and a new inverted index structure for video documents. We evaluate the storage requirement and the disk access time of the scheme and present the analytical results.

• Journal of Information Processing Systems
• /
• v.11 no.3
• /
• pp.389-405
• /
• 2015

Most traditional database systems exploit a record-oriented model where the attributes of a record are placed contiguously in a hard disk to achieve high performance writes. However, for read-mostly data warehouse systems, the column-oriented database has become a proper model because of its superior read performance. Today, flash memory is largely recognized as the preferred storage media for high-speed database systems. In this paper, we introduce a column-oriented database model based on flash memory and then propose a new column-aware flash indexing scheme for the high-speed column-oriented data warehouse systems. Our index management scheme, which uses an enhanced $B^+$-Tree, achieves superior search performance by indexing an embedded segment and packing an unused space in internal and leaf nodes. Based on the performance results of two test databases, we concluded that the column-aware flash index management outperforms the traditional scheme in the respect of the mixed operation throughput and its response time.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2011.04a
• /
• pp.204-206
• /
• 2011

기존의 TAR와 같은 아카이브 포맷은 파일의 중복을 제거하는 기능이 포함되지 않아 리눅스 배포 미러와 같이 버전단위로 저장되는 시스템에서 디스크 공간의 낭비가 발생했다. 본 연구에서는 중복 제거 기능이 포함된 아카이브 포맷인 DTAR와 이를 지원하는 DTM 유틸리티를 제안하였다. 주요 아이디어는 DTAR 헤더에 SHA1 해시를 삽입하고 SHA1 해시를 노드로 하는 R-B Tree를 생성하여 중복을 검색 및 제거하는 것이다. 실험 결과 DTAR가 tar.gz보다 최대 31% 공간을 절약하고, 수행 시간도 줄어드는 것을 확인하여 효율적임을 보였다.

• Journal of Korea Spatial Information System Society
• /
• v.8 no.2 s.17
• /
• pp.53-73
• /
• 2006

Recently, the need for Location-Based Services (LBS) has increased due to the development of mobile devices, such as PDAs, cellular phones and GPS. As a moving object database that stores and manages the positions of moving objects is the core technology of LBS, the scheme for maintaining the main memory DBMS to the server is necessary to store and process frequent reported positions of moving objects efficiently. However, previous works on a moving object database have studied mostly a disk based moving object index that is not guaranteed to work efficiently in the main memory DBMS because these indexes did not consider characteristics of the main memory. It is necessary to study the main memory index scheme for a moving object database. In this paper, we propose the main memory index scheme based on the R-tree for storing and processing positions of moving objects efficiently in the main memory DBMS. The proposed index scheme, which uses a growing node structure, prevents the splitting cost from increasing by delaying the node splitting when a node overflows. The proposed scheme also improves the search performance by using a MergeAndSplit policy for reducing overlaps between nodes and a LargeDomainNodeSplit policy for reducing a ratio of a domain size occupied by node's MBRs. Our experiments show that the proposed index scheme outperforms the existing index scheme on the maximum 30% for range queries.