• Journal of the Korean Wood Science and Technology
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• v.47 no.2
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• pp.229-238
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• 2019

Various wood defects occur during tree growing or wood processing. Thus, to use wood practically, it is necessary to objectively assess their quality based on the usage requirement by accurately classifying their defects. However, manual visual grading and species classification may result in differences due to subjective decisions; therefore, computer-vision-based image analysis is required for the objective evaluation of wood quality and the speeding up of wood production. In this study, the SIFT+k-NN and CNN models were used to implement a model that automatically classifies knots and analyze its accuracy. Toward this end, a total of 1,172 knot images in various shapes from five domestic conifers were used for learning and validation. For the SIFT+k-NN model, SIFT technology was used to extract properties from the knot images and k-NN was used for the classification, resulting in the classification with an accuracy of up to 60.53% when k-index was 17. The CNN model comprised 8 convolution layers and 3 hidden layers, and its maximum accuracy was 88.09% after 1205 epoch, which was higher than that of the SIFT+k-NN model. Moreover, if there is a large difference in the number of images by knot types, the SIFT+k-NN tended to show a learning biased toward the knot type with a higher number of images, whereas the CNN model did not show a drastic bias regardless of the difference in the number of images. Therefore, the CNN model showed better performance in knot classification. It is determined that the wood knot classification by the CNN model will show a sufficient accuracy in its practical applicability.

• Applied Microscopy
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• v.36 no.4
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• pp.251-258
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• 2006

Crystal-bearing cells are rarely encountered in the softwoods and their regular occurrence, e.g., in species of Abies, Picea, Ginkgo, and Pinus, is of considerable diagnostic significance. Thus, this study discusses the distribution and types of crystals in North American Abies species to provide additional information for wood anatomy and identification through light and scanning electron microscopies. Prismatic crystals, elongate crystal s, and styloids are identified, in descending order of frequency, in Abies concolor, A. grandis. and A. magnifica, A. nobilis (=A. procera), A. lasiocarpa, and A. amabilis but not in A. balsamea and A. fraseri. Differently from the other species, A. lasiocarpa shows the tendency of more elongate crystals and styloids than prismatic crystals. A. concolor contains crystal sands, prismatic crystals, elongate crystals, and styloids both in the axial and ray parenchyma cells, whereas the other species show prismatic crystals, elongate crystals, and styloids only in the ray parenchyma cells. Ray parenchyma cells containing crystal sand and axial parenchyma cells having crystal sand, prismatic crystals, elongate crystals, and styloids are probably reported here for the first time in A. concolor. In conclusion, the presence or absence of crystals appears to be the most powerful diagnostic character for separating A. concolor, A. grandis, and A. magnifica from A. nobilis (=A. procera), A. lasiocarpa, A. amabilits, A. balsamea, and A. fraseri.

• Conservation Science in Museum
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• v.16
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• pp.138-153
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• 2015

Wooden standing Bodhisattva in the collection of the National Museum of Korea (Bon 8239) was purchased as part of the museum's Central Asian collection during the Museum of Japanese Goverment General of Korea. The wooden statue exhibiting classical characteristics of Song Dynasty Buddhist sculptures is colored on the whone. The result of condition check for exhibition in 2014, it has severely damaged, with discoloring and exfoliation in color pigment and crack of wood observed in various areas. The object was therefore treated for conservation. A series of analysis were performed also at this time to determine the production technique and the materials, including testing of the X-ray penetration depth, X-ray fluorescence analysis and wood species analysis. This revealed that the statue was made by joining several separate pieces of wood. As for color pigments, the white pigment was either chalk (CaCO₃) or gypsum(CaSO₄·2H₂O), and the green pigment was emerald green (Cu(C₂H₃O₂)₂·3Cu(AsO₂)₂). The red pigment appeared to be lead red(Pb₃O₄) and the blue pigment was ultramarine blue (3Na₂O·3Al₂O₃·6SiO₂·2Na₂S). All the pigments were repainted in later eras. The analysis, indicated that the wood was derived from a tree of the genus Populus, family Salicaceae. The wooden standing Bodhisattva was repaired and reinforced with natural materials and was brought to a stable condition necessary for display.

• Journal of the Korean Wood Science and Technology
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• v.36 no.4
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• pp.1-10
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• 2008

A series of the studies on the applied physical properties of domestic species have been conducted last three years. Pinus koraiensis and Larix kaempferi were two of the three species examined for the first year. Because the same apparatus and experimental procedures were used for all species, their results can be easily comparable. The experiments for sorption property were conducted with 20- and 80-mesh wood powder and resulted in their EMCs and sorption isotherms at various RH conditions. The thermal conductivity and diffusivity, and electric resistance and volumetric electric resistivity were measured with a thermal-wire device and a high electric resistance meter. The differences in the thermal and electric properties between quarter- and flat-sawn specimens were observed, which were partially attributed to their anatomical differences. An acoustic measurement system was used to evaluate dynamic MOE and internal friction. This paper provides the useful fundamental data for designing a wood structure, correcting a portable resistance-type moisture meter, and acoustic properties of wood.

• Journal of Conservation Science
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• v.34 no.5
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• pp.359-368
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• 2018

The purpose of this study was to analyze the wood species of the stern plank and persimmon seed from Daebudo shipwreck No.2 excavated from Daebudo, Danwon-gu, Ansan-si, and Gyeonggi-do by wiggle-matching of radiocarbon measurements. Results of the analysis showed that all the wooden boards of the hull were made from Pinus Hard Pine Group. The other parts of hull and wooden pegs were made from Pinus Hard Pine Group, Castanea spp., Quercus spp. sect. Lepidobalanus, Alnus spp., and Zelkova serrata Makino. Excavated wide-tooth wooden comb and fine-tooth bamboo comb were made from Acer spp. and Bambusoideae. Excavated rope was made from Pueraria thunbergiana Benth. The stern plank, wooden support, and persimmon stone showed ${\pm}2{\sigma}$ radiocarbon date(95.4% confidence interval) of AD 1151-1224. This indicated that the Daebudo shipwreck No.2 occurred during the early or middle 12-13th century. Our radiocarbon dating results confirmed the date speculated by archeologists based on the ceramic style.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.244-250
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• 2014

This study was conducted to identify wood species of 72 wooden parts (pillar, beam, jangyeo, purlin, judu, soro, bracket, deagong, ceiling panel, etc.) used for Daewungjeon Hall in the Woonsoosa Temple, Busan in Korea. Identified wood species were 67 Pinus spp. (Kesiya group), 4 Carpinus spp. and 1 Quercus spp. (Cerris group). In pillars, 14 red pines and 4 Carpinus and in purlins, 4 red pines and 1 Cerris were found. Other elements were red pines. Carpinus woods, which were used for the lower portions of three pillars (Dongbari), seemed repaired parts. A carved wood used for the stand of Buddhist statues was identified as Alnus spp. This study showed that Daewungjeon Hall of the Woonsoosa Temple was made mostly of red pines.

• Journal of the Korean Wood Science and Technology
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• v.39 no.4
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• pp.281-290
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• 2011

We analyzed the basic characteristics and adsorption property of carbonized materials from thinning byproducts of major Korean wood species for evaluating as charcoal making raw material. Yield of charcoal was decreased with increasing the carbonization temperature for all wood species. Refining degrees was 9.0 at $400^{\circ}C$, 3.3~5.0 at $600^{\circ}C$ and 0 at $800^{\circ}C$, and was no difference among wood species. With increasing the carbonization temperature, the fixed carbon content was also increased, and charcoal from softwoods had more fixed carbon content than that from hardwoods. Specific surface area was increased with increasing the carbonization temperature, softwood charcoal had more specific surface area than that of hardwood. Pinus rigida showed the highest specific surface area. In formaldehyde removal by charcoal, some materials had highest at $600^{\circ}C$ and the others had highest at $800^{\circ}C$. Pinus koraiensis, Qurcus acutissima and MDF showed maximum formaldehyde removal ability at $600^{\circ}C$. Ethylene gas removal ability of charcoal was increased with increasing the carbonization temperature, and the charcoal from Pinus rigida and Robinia pseudoacacia had higher ethylene gas removal ability than the other species.

• Journal of the Korean Wood Science and Technology
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• v.30 no.1
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• pp.40-47
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• 2002

This study was carried out to investigate the dimensional stability of three softwoods (Pinus densiflora S. et Z., Pinus koraiensis S. et Z., Larix kaempferi C_ARR.) and two hardwoods(Quercus mongolica F., Quercus variabilis B_L.) treated with polyethylene glycol(PEG). Existence of PEG in wood was examined by an X-ray diffraction method. Shrinkage of the sample woods decreased with increasing concentration of PEG. The dimensional stability of five species had improved highly in thirty percent solutions of PEG with molecular weight 1000~4000, and the dimension of PEG-treated softwoods was more stable than that of PEG-treated hardwoods. Weight gain and bulking effect of the woods treated with PEG increased with increasing concentration of PEG. X-ray diffractograms of Pinus koraiensis wood treated with PEG showed two peaks derived from PEG crystal at 2𝜃 = 19° and 2𝜃 = 23°. However, the diffractograms of Quercus mongolica wood did not present any peaks caused by PEG crystal. From the result of X-ray diffraction, it was revealed that the content of PEG in Pinus koraiensis wood was higher than that in Quercus mongolica wood.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.68-87
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• 1982

In Korea, this is the situation at moment that the total demand of timber in 1972 is more than 5 million cubic meters. On the other hand, however, the available domestic supply of timber at the same year is only about, 1 million cubic meters. A great unbalancing between demand and supply of timber has been prevailing. To solve this hard problem, it has been necessitiated to build up the forest stocks as early as possible with fast grown species such as poplar. Under circumstances, poplar plantations which have been carryed on government and private have reached to large area of 116,603 hectors from 1962 up to date. It has now be come a principal timber resources in this country, and required the basic study on various properties of wood for it's proper utilization, since it has not been made of any systematic study on the properties of Populus grown in Korea. In order to investigate the properties such as anatomical, physical and mechanical properties of nine different species (P. euramericana Guiner I-214. P. euramericana Guiner I-476, P. deltoides Marsh, P. nigra var. italica (Muchk) Koeme, P. alba L.,P. alba $\times$ glandulosa P. maximowiczii Henry, P. koreana Rehder, P. davidiana Dode) of poplar for their proper use and development of new ways of grading processing and quality improving, this study has been made by the Forest Research Institute.

• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.19-29
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• 2016

The purpose of this study is to analyze the combustion and thermal properties in order to establish baseline data for the fire safety evaluation of imported wood. The combustion properties such as heat release rate, total heat release, gas yield, and mass loss were analyzed by the method of cone calorimeter test according to KS F ISO 5660-1 and thermogravimetric analysis (TGA). Analyzed species are five kinds of species as Merbau, Mempening, Garo Garo, Malas, and Dillenia. The heat released rate values showed the highest value of Malas as $375.52kW/m^2$, and Dillenia showed the lowest value as $133.30kW/m^2$. The data values were confirmed in the following order: Malas > Mempening > Garo Garo > Merbau > Dillenia. In case of the total heat release, it was measured in the following order: Mempening > Malas > Garo Garo > Merbau > Dillenia. The gas analysis results were that Dillenia showed the highest value of 0.034. Also, Mempening and Malas showed the lowest at 0.020 in the $CO/CO_2$. Min of mass reduction was shown as 74.79% Sargent cherry, on the other hand, Malas had a 83.52%. It showed a correlation between and of the CO and $CO_2$ generation and combustion characteristics of wood. The thermal decomposition temperature of the wood in the TGA were as follow that Merbau $348.07^{\circ}C$, Mempening $367.57^{\circ}C$, Garo Garo $350.59^{\circ}C$, Malas $352.41^{\circ}C$, Dillenia $364.33^{\circ}C$. The aim of this study is to determine the combustion properties of imported wood according to ISO 5660-1. And, based on the results of this study, we would proceed with further research for improving the fire safety of wood for construction.