• Spatial Information Research
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• v.19 no.4
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• pp.45-54
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• 2011

In this paper, we propose a hybrid index structure, called the SQMR-tree(Spatial Quad MR-tree) that can process spatial data efficiently by combining advantages of the MR-tree and the SQR-tree. The MR-tree is an extended R-tree using a mapping tree to access directly to leaf nodes of the R-tree and the SQR-tree is a combination of the SQ-tree(Spatial Quad-tree) which is an extended Quad-tree to process spatial objects with non-zero area and the R-tree which actually stores spatial objects and are associated with each leaf node of the SQ-tree. The SQMR-tree consists of the SQR-tree as the base structure and the mapping trees associated with each R-tree of the SQR-tree. Therefore, because spatial objects are distributedly inserted into several R-trees and only R-trees intersected with the query area are accessed to process spatial queries like the SQR-tree, the query processing cost of the SQMR-tree can be reduced. Moreover, the search performance of the SQMR-tree is improved by using the mapping trees to access directly to leaf nodes of the R-tree without tree traversal like the MR-tree. Finally, we proved superiority of the SQMR-tree through experiments.

• Spatial Information Research
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• v.18 no.4
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• pp.109-120
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• 2010

Recently, due to rapid increasement of spatial data collected from various geosensors in u-GIS environments, the importance of spatial index for efficient search of large spatial data is rising gradually. Especially, researches based R-Tree to improve search performance of spatial data have been actively performed. These previous researches focus on reducing overlaps between nodes or the height of the R -Tree. However, these can not solve an unnecessary node access problem efficiently occurred in tree traversal. In this paper, we propose a MR-Tree(Mapping-based R-Tree) to solve this problem and to support efficient search of large spatial data. The MR-Tree can improve search performance by using a mapping tree for direct access to leaf nodes of the R-Tree without tree traversal. The mapping tree is composed with MBRs and pointers of R-Tree leaf nodes associating each partition which is made by splitting data area repeatedly along dimensions. Especially, the MR-Tree can be adopted in various variations of the R-Tree easily without a modification of the R-Tree structure. In addition, because the mapping tree is constructed in main memory, search time can be greatly reduced. Finally, we proved superiority of MR-Tree performance through experiments.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.8
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• pp.758-762
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• 2008

Embedded systems usually utilize Flash Memories with very nice characteristics of non-volatility, low access time, low power and so on. For the multimedia database systems, R-tree is an indexing tree with nice characteristics for multimedia access. MR-tree, which is an upgraded version of R-tree, has shown better performance in searching, inserting and deleting operations than R-tree. Flash memory has sectors and blocks as a unit of read, write and delete operations. Especially, the delete is done on a unit of 512 byte blocks with very large operation time and it is also known that read and write operations on a unit of block matches caching nature of MT-tree. Our research optimizes MR-tree operations in a unit of Flash memory blocks. Such an adjusting leads in better indexing performance in database accesses. With MR-tree on a 512B block units we achieved fast search time of database indexing with low height of MR-tree as well as faster update time of database indexing with the best fit of flash memory blocks. Thus MR-tree with optimized operations shows good characteristics to be a database index schemes on any systems with flash memory.

• Journal of KIISE:Databases
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• v.30 no.6
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• pp.651-665
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• 2003

To reduce cache misses emerges as the most important issue in today's situation of main memory databases, in which CPU speeds have been increasing at 60% per year, and memory speeds at 10% per year. Recent researches have demonstrated that cache-conscious index structure such as the CR-tree outperforms the R-tree variants. Its search performance can be poor than the original R-tree, however, since it uses a lossy compression scheme. In this paper, we propose alternatively a cache-conscious version of the R-tree, which we call MR-tree. The MR-tree propagates node splits upward only if one of the internal nodes on the insertion path has empty room. Thus, the internal nodes of the MR-tree are almost 100% full. In case there is no empty room on the insertion path, a newly-created leaf simply becomes a child of the split leaf. The height of the MR-tree increases according to the sequence of inserting objects. Thus, the HeightBalance algorithm is executed when unbalanced heights of child nodes are detected. Additionally, we also propose the CCMR-tree in order to build a more cache-conscious MR-tree. Our experimental and analytical study shows that the two-dimensional MR-tree performs search up to 2.4times faster than the ordinary R-tree while maintaining slightly better update performance and using similar memory space.

• The KIPS Transactions:PartD
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• v.11D no.1
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• pp.11-22
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• 2004

As random access memory chip gets cheaper, it becomes affordable to realize main memory-based database systems. Consequently, reducing cache misses emerges as the most important issue in current main memory databases, in which CPU speeds have been increasing at 60% per year, compared to the memory speeds at 10% per you. In this paper, we design and implement a main-memory database system for real-time mobile GIS. Our system is composed of 5 modules： the interface manager provides the interface for PDA users； the memory data manager controls spatial and non-spatial data in main-memory using virtual memory techniques； the query manager processes spatial and non-spatial query : the index manager manages the MR-tree index for spatial data and the T-tree index for non-spatial index : the GIS server interface provides the interface with disk-based GIS. The MR-tree proposed propagates node splits upward only if one of the internal nodes on the insertion path has empty space. Thus, the internal nodes of the MR-tree are almost 100% full. Our experimental study shows that the two-dimensional MR-tree performs search up to 2.4 times faster than the ordinary R-tree. To use virtual memory techniques, the memory data manager uses page tables for spatial data, non- spatial data, T-tree and MR-tree. And, it uses indirect addressing techniques for fast reloading from disk.

• Ocean Systems Engineering
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• v.8 no.2
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• pp.101-118
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• 2018

In case of conventional shallow-draft semisubmersibles, unacceptably large riser stroke was the restricting factor for dry-tree-riser-semisubmersible development. Many attempts to address this issue have focused on using larger draft and size with extra heave-damping plates, which results in a huge cost increase. The objective of this paper is to investigate an alternative solution by improving riser systems through the implementation of a magneto-rheological damper (MR Damper) so that it can be used with moderate-size/draft semisubmersibles. In this regard, MR-damper riser systems and connections are numerically modeled so that they can couple with hull-mooring time-domain simulations. The simulation results show that the moderate-size semisubmersible with MR damper system can be used with conventional dry-tree pneumatic tensioners by effectively reducing stroke-distance even in the most severe (1000-yr) storm environments. Furthermore, the damping level of the MR damper can be controlled to best fit target cases by changing input electric currents. The reduction in stroke allows smaller topside deck spacing, which in turn leads to smaller deck and hull. As the penalty of reducing riser stroke by MR damper, the force on the MR-damper can significantly be increased, which requires applying optimal electric currents.

• Analytical Science and Technology
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• v.30 no.3
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• pp.130-137
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• 2017

The leaves (Mori Folium; MF), branches (Mori Ramulus; MR), and root bark (Mori Cortex Radicis; MCR) of the mulberry tree have been used as therapeutic herbs for centuries. Existing analytical methods were developed specifically for different parts of the tree and cannot be applied to samples containing a mixture of tree parts. Such method specialization is time-consuming and requires separate identification and quality control of each tree part. This report describes an HPLC method for the simultaneous quality control and discrimination of MF, MR, and MCR using four marker compounds: rutin, kuwanon G, oxyresveratrol, and morusin. An Optimapak $C_{18}$ column ($4.6{\times}250mm$, $5{\mu}m$) was used with a gradient elution of 0.1 % formic acid in water and acetonitrile. The flow rate was 1.0 mL/min and the detection wavelength was 270 nm. In quantitative analyses of the three parts, rutin (0.11 % w/w) was detected only in MF. The oxyresveratrol content (0.12 % w/w) was highest in MR. Kuwanon G (0.33 % w/w) and morusin (0.18 % w/w) were higher in MCR than in other parts. The HPLC method given herein can be used to simultaneously classify and quantify three herbal medicines from the mulberry tree.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04a
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• pp.341-344
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• 2001

본 논문에서는 학습을 수행하여 뇌 MR 이미지를 자동으로 분류하고 검색하는 시스템을 설계하였다. 이미지로부터 얻을 수 있는 정보는 크게 두 가지 부류로 나눌 수 있다. 이미지 자체로부터 얻을수 있는 크기, 색상, 질감, 윤곽선 등의 하위레벨(low-level) 정보가 있고, 이미지 의미 해석에서 오는 전이, 포함, 방향, 등의 상위레벨(high-level) 정보가 있다. 이 논문은 의료 이미지에 대하여 상위 및 하위 레벨 정보의 각 특징을 살리고 효과적으로 검색하기 위해, 두 부류의 이미지 정보에 대한 결정 트리(Decision Tree) 학습을 2 단계로 적용하여 이미지를 분류하도록 시스템을 설계하였다.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.2
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• pp.127-133
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• 2006

Shewanella oneidensis MR-1 has the ability to inhale certain metals and chemical compounds and exhale these materials in an altered state; as a result, this microorganism has been widely applied in bioremediation protocols. However, the relevant characteristics of cell growth and biosynthesis of PuFAs have yet to be thoroughly investigated. Therefore, in this study, we have attempted to characterize the growth and fatty acid profiles of S. oneidensis MR-1 under a variety of temperature conditions. The fastest growth of S. oneidensis MR-1 was observed at $30^{\circ}C$, with a specific growth rate and doubling time of $0.6885h^{-1}\;and\;1.007 h$. The maximum cell mass of this microorganism was elicited at a temperature of $4^{\circ}C$. The eicosapentaenoic acid (EPA) synthesis of S. oneidensis MR-1 was evaluated under these different culture temperatures. S. oneidensis MR-1 was found not to synthesize EPA at temperatures in excess of $30^{\circ}C$, but was shown to synthesize EPA at temperatures below $30^{\circ}C$. The EPA content was found to increase with decreases in temperature. We then evaluated the EPA biosynthetic pathway, using a phylogenetic tree predicted on 16s rRNA sequences, and the homology of ORFs between S. oneidensis MR-1 and Shewanella putrefaciens SCRC-2738, which is known to harbor a polyketide synthase (PKS)-like module. The phylogenetic tree revealed that MR-1 was very closely related to both Moritella sp., which is known to synthesize DHA via a PKS-like pathway, and S. putrefaciens, which has been reported to synthesize EPA via an identical pathway. The homology between the PKS-like module of S. putrefaciens SCRC-2738 and the entire genome of S. oneidensis MR-1 was also analyzed, in order to mine the genes associated with the PKS-like pathway in S. oneidensis MR-1. A putative PKS-like module for EPA biosynthesis was verified by this analysis, and was also corroborated by the experimental finding that S. oneidensis MR-1 was able to synthesize EPA without the expression of $dihomo-{\gamma}-linoleic$ acid (DGLA) and arachidonic acid (AA) formed during EPA synthesis via the FAS pathway.

• Communications of the Korean Mathematical Society
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• v.27 no.4
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• pp.665-668
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• 2012

For a given graph G we consider a set S(G) of all symmetric matrices A = [$a_{ij}$] whose nonzero entries are placed according to the location of the edges of the graph, i.e., for $i{\neq}j$, $a_{ij}{\neq}0$ if and only if vertex $i$ is adjacent to vertex $j$. The minimum rank mr(G) of the graph G is defined to be the smallest rank of a matrix in S(G). In general the computation of mr(G) is complicated, and so is that of the maximum multiplicity MaxMult(G) of an eigenvalue of a matrix in S(G) which is equal to $n$ - mr(G) where n is the number of vertices in G. However, for trees T, there is a recursive formula to compute MaxMult(T). In this note we show that this recursive formula for MaxMult(T) also computes the path cover number $p$(T) of the tree T. This gives an alternative proof of the interesting result, MaxMult(T) = $p$(T).