• Journal of KIISE:Databases
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• v.29 no.5
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• pp.367-380
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• 2002

Due to recent increase in applications requiring huge amount of data such as spatial data analysis and image analysis, clustering on large databases has been actively studied. In a hierarchical clustering method, a tree representing hierarchical decomposition of the database is first created, and then, used for efficient clustering. Existing hierarchical clustering methods mainly adopted the bottom-up approach, which creates a tree from the bottom to the topmost level of the hierarchy. These bottom-up methods require at least one scan over the entire database in order to build the tree and need to search most nodes of the tree since the clustering algorithm starts from the leaf level. In this paper, we propose a novel top-down hierarchical clustering method that uses multidimensional indexes that are already maintained in most database applications. Generally, multidimensional indexes have the clustering property storing similar objects in the same (or adjacent) data pares. Using this property we can find adjacent objects without calculating distances among them. We first formally define the cluster based on the density of objects. For the definition, we propose the concept of the region contrast partition based on the density of the region. To speed up the clustering algorithm, we use the branch-and-bound algorithm. We propose the bounds and formally prove their correctness. Experimental results show that the proposed method is at least as effective in quality of clustering as BIRCH, a bottom-up hierarchical clustering method, while reducing the number of page accesses by up to 26～187 times depending on the size of the database. As a result, we believe that the proposed method significantly improves the clustering performance in large databases and is practically usable in various database applications.

• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.87-94
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• 2002

This study was carried out to evaluate bending property on principal domestic species such as sargent cherry(Prunus sargentii), bitter wood(Picrasma quassioides), horn beam(Carpinus laxiflora), cork oak(Quercus variabilis), birch(Betula schmidtii), painted maple(Acer mono), basswood(Tilia amurensis), red pine(Pinus densiflora), pitch pine(Pinus rigtda), royal pawlonia(Paulownia tomentosa) by microwave heating. In this study, radius of curvature(ROC) for bending process was classified by radius of curvature(ROC) of bending plate such as 4 cm, 6 cm, and 10 cm, and thickness of metal-strap(TMS) was 0.6 mm and 0.8 mm. Bending process was successfully operated for 100 percent in bitter wood, horn beam, birch and painted maple. On the other hand, there was a success rate of 58 percent in sargent cherry and 83 percent in cork oak and 29 percent in basswood and 8 percent in royal pawlonia which is the worst bending property. All specimens of basswood and royal pawlonia were broken at 4 cm of ROC. Success rate of bending property was shown 44 percent in red pine and 56 percent in pitch pine. TMS has an effect on only drying speed in drying process than difficulty and facility of bending property. It was considered that the thinner TMS in drying process is the faster in drying speed of bent wood.

• Journal of Mushroom
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• v.2 no.4
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• pp.214-217
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• 2004

This study was carried out to investigate the physiological charateristics of F. pinicola in sawdust media. The optimum temperature in sawdust media was $30^{\circ}C$ in of F. pinicola. The optimum pH was 5 in F. pinicola. Mycelial growth and density of F. pinicola was quite good when birch tree and oak sawdust, respectively were used as cultural substrates. The best mycelial growth in F. pinicola was observed when beer waste was added as supplement on sawdust substrates. The optimum supplement ratios of beer waste and a magnecium sulfate were 20%, and 0.1% respectively. However, optimun supplement ratios of a calcium oxide and a LVD were different as 0.1% in F. pinicola.

• Journal of the Korea Furniture Society
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• v.18 no.2
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• pp.143-146
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• 2007

This study was carried out to assess the dimensional stability of wood material treated by plastic processing for bentwood and compression wood. The evaluation method was different between two wood materials, but the treatments for them were very similar to each other. One of the main methods is heat treatment with sufficient water vapor. In bentwood, the used species were painted maple (Acer mono), bitter wood (Picrasma quassioides) and birch (Betula schmidtii). Steaming was the worst treatment method for dimensional stabilization of bentwood. The best results could be attained with PEG treatment for dimensional stabilization of bentwood. Dimensional stability of bitter wood was found to be conspicuous. However the steaming treatment at lower temperatures, i.e., about $130^{\circ}C$ was not suitable for dimensional stability of bentwood. In compression wood, the used specimen was Italian poplar wood (Populus euramericana). Two heat compressive pressing conditions, an open-press system and an air-tighten closed-press system, were used. The recovery rate was measured after boiling and/or absorbing in water to estimate the dimensional stability of heat compressed wood. The best dimensional stability of compressed wood in the air-tighten closed-press system was found to be better at $200^{\circ}C$ than $180^{\circ}C$. The best compression rate for dimensional stability was 73 percent.

• YAKHAK HOEJI
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• v.52 no.1
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• pp.37-42
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• 2008

Betulinic acid, a naturally occurring pentacyclic triterpenoid, is found in abundance in the outer bark of white birch (Betula alba). In this study, we investigated if betulinic acid affects cytokine expression from activated macrophage cells. ELISA result showed that stimulation of HL-60 cells with proinflammatory cytokine such as $TNF-{\alpha}$ resulted in MCP-1 release into culture medium. In addition, transcriptional upregulation of MCP-1 in response to $TNF-{\alpha}$ was observed by RT-PCR analysis. However, incubation of HL-60 cells with betulinic acid prior to $TNF-{\alpha}$ treatment abrogated MCP-1 expression in transcription and translational level. Consistent with a number of studies which reported requirement of ERK activation for $TNF-{\alpha}$ expression, Western blot analysis showed that $TNF-{\alpha}-induced$ ERK activation was suppressed by pretreatment of HL-60 cells with betulinic acid. Taken together, our data indicate that betulinic acid exerts its anti-inflammatory effect through inhibition of $TNF-{\alpha}-induced$ ERK activation which is required for the subsequent MCP-1 release.

• Journal of Acupuncture Research
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• v.35 no.2
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• pp.47-51
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• 2018

Acupuncture is a complex intervention that manifests varied theories, treatment methods, diagnostic methods and diagnostic patterns. Traditionally based systems of acupuncture (TBSAs) often have their own diagnostic approaches and patterns. Despite the wide variety that can be found amongst TBSAs, is it possible that they share a common background in clinical observation and practice? Research has shown that multiple physiological pathways and mechanisms can be triggered by different acupuncture techniques and methods. It is highly likely that clinicians will have observed some of the effects of these responses and used those observations as feedback to help construct the patterns of diagnosis and their associated treatments. This review briefly examines this possibility. Pattern identification will have developed out of a complex interaction of factors that include; theories current at the time of their development, historical theories, personal choices and beliefs, training, practice methods, clinical observations and the natural feedback that comes from observing how things change once the treatment is applied. Researchers investigating TBSAs and pattern identification need to be more explicit about the systems they have investigated in order to understand the biological basis of pattern identification and their treatments.

• Journal for History of Mathematics
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• v.28 no.2
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• pp.85-102
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• 2015

Elliptic curves are a common theme among various fields of mathematics, such as number theory, algebraic geometry, complex analysis, cryptography, and mathematical physics. In the history of elliptic curves, we can find number theoretic problems on the one hand, and complex function theoretic ones on the other. The elliptic curve theory is a synthesis of those two indeed. As an overview of the history of elliptic curves, we survey the Diophantine equations of 3rd degree and the congruent number problem as some of number theoretic trails of elliptic curves. We discuss elliptic integrals and elliptic functions, from which we get a glimpse of idea where the name 'elliptic curve' came from. We explain how the solution of Diophantine equations of 3rd degree and elliptic functions are related. Finally we outline the BSD conjecture, one of the 7 millennium problems proposed by the Clay Math Institute, as an important problem concerning elliptic curves.

• Journal of the Korean Wood Science and Technology
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• v.20 no.4
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• pp.65-72
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• 1992

Steam defiberated pulp and steam exploded wood(birch chip) were extracted with solvents (hot-water, 1% NaOH, MeOH, hot water, 1% NaOH). The properties of residual fiber were examined for the utilization as ruminants feed. The digestibility is 38% in steam defiberated pulp(10kg /$cm^2$-15min) and 62-77% in exploded wood(17-18kg/$cm^2$-2~10min), respectively. The more steam pressure and time increase, the more the digestibility increase. The sugars obtained from extractives is amount from 7% to 13% in asplund pulp and from 7% to 10% in exploded pulp. The sugars was mainly composed of 70-80% xylose. The digestibility of residual fiber which is extracted with solvents is low than these of original fibers. Considering the yield and digestibility as ruminant feed, exploded pulp under 17kg /$cm^2$ for 10min has the best efficiency. The exploded wood gives 75.3% on yield(O. D. chip) and 48% on the digestibility.

• Korean Institute of Interior Design Journal
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• v.13 no.6
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• pp.140-149
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• 2004

The bentwood technique was introduced for the Windsor chair for the first time in the 18th Century. It was Michael Thonet who produced the bentwood chair in Austria around the 1870's, and it has changed the perception of architects and designers since then. The bentwood chair suggested a new and eccentric way of manufacturing furniture and the process of producing materials for it. Moreover, the method of furniture assembling, with screw nails, made a positive contribution not only to the convenience of transport and distribution of furniture to anywhere in the world, but also to the development of mass production of furniture for the multitudes. The bentwood technique of Michael Thonet was developed much further by Alvar Aalto, who inferred a soft curve from nature and developed the beauty of modern laminated bentwood by using birch, a plentiful resource of Finland. This study will help us to understand the functions and process of bentwood furniture, and help to develop technical skills for diverse furniture design. It will also confirm that diverse bentwood furniture design will be possible by applying materials, technical skills and the design process of bentwood according to the characteristics and concept of furniture design.

• Mycobiology
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• v.36 no.4
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• pp.199-202
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• 2008

Inonotus obliquus is a fungus that causes white heart rot on several broad-leaved species. This fungus forms typical charcoal-black, sterile conks (chaga) or cinder conks on infected stems of the birche (Betula spp). The dark brown pulp of the sterile conk is formed by a pure mycelial mass of fungus. Chaga are a folk remedy in Russia, reflecting the circumboreal distribution of I. obliquus in boreal forest ecosystems on Betula spp. and in meridional mountain forests on beech (Fagus spp.) in Russia, Scandinavia, Central Europe, and Eastern Europe. Distribution at lower latitudes in Western and Southern Europe, Northern America, Asia, Japan, and Korea is rare. Infected trees grow for many years without several symptoms of decline. The infection can penetrate through stem injuries with exterior sterile conks developing later. In the Czech Republic, cinder conk is found on birches inhabiting peat bogs and in mountain areas with a colder and more humid climate, although it is widespread in other broad leaved species over the Czech Republic. The most common hosts are B. pendula, B. pubescens, B. carpatica, and F. sylvatica. Less frequent hosts include Acer campestre, Acer pseudoplatanus, Alnus glutinosa, Alnus incana, Fraxinus excelsior, Quercus cerris, Q. petraea, Q. robur, Q. delachampii, and Ulmus sp.