• Journal of the Korean Wood Science and Technology
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• 제47권4호
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• pp.519-532
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• 2019

The objectives of this study were to evaluate the effects of shelling ratio and resin content on the properties of bamboo oriented strand board (BOSB) from betung (Dendrocalamus asper) and to determine the correlation between the results of dynamic and static bending tests. Strands were steam-treated at $126^{\circ}C$ for 1 h under 0.14 MPa pressure and followed by washing with 1% NaOH solution. Three-layer BOSB with the core layer perpendicular to the surface was formed with shelling ratios (face:core ratio) of 30:70; 40:60; 50:50; 60:40 and binded with 7% and 8% of phenol formaldehyde (PF) resin with the addition of 1% of wax. The evaluation of physical and mechanical properties of BOSB was conducted in accordance with the JIS A 5908:2003 standard and the results were compared with CSA 0437.0 standard for commercial OSB (Grade O-1). Non-destructive testing was conducted using Metriguard Model 239A Stress Wave Timer which has a wave propagation time from 1 to $9,999{\mu}s$ and a resolution of $1{\mu}s$. BOSB with 8% resin content showed better physical and mechanical properties than those with 7% resin content. The increase of the face layer ratio improved the strength of BOSB in parallel direction to the grain. The results suggested that shelling ratio of 50:50 could be used as a simple way to reduce PF resin requirements from 8% to 7% and to meet the requirements of CSA 0437.0 standard. The results of non-destructive and destructive tests showed a strong correlation, suggesting that non-destructive test can be used to estimate the bending properties of BOSB.

• 교육시설
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• 제7권2호
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• pp.15-21
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• 2000

Microclimate of open spaces on campus tends to be important because it is related with people's comfort and it can influences their behaviors in outdoor during summer. Climatic components for 4 points, concrete paving, lawn, landscaped pergola and nearby forest on university campus were measured and evaluated. The results show that the air temperatures on paving such as concrete and lawn under the direct solar radiation were higher than the temperatures of canopied spaces such as pergora and nearby forest by up to $7^{\circ}C$ during summer. Characteristics of temperatures on lawn were similar to those on concrete paving. After evaluation, concrete surface was worst among 4 points, while landscaped pergola was the most effective facility in terms of thermal comfort during summer.

• 한국환경복원기술학회지
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• 제5권3호
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• pp.50-57
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• 2002

The restoration techniques of large disturbed land containing native forest resources and soil animals were investigated on the new campus area of Kyushu University in Japan. Important techniques to restore native forest and biodiversity in that area are transplantation of existing large trees, transplantation of the forest soil, transplantation of native tree stools, and the reuse of wood and bamboo chips. The benefits can be obtained by using these methods. Firstly, the native genetic resources that would be discarded as part of the land development can be reused. Secondary, the time taken to become a high growth forest as opposed to the practice of planting saplings or grass seeds can be reduced. At last, the native forest ecosystem containing various under-story vegetations and soil animals can be conserved and regenerated. In addition, big and small ponds were constructed in the biodiversity preservation zone to preserve rare plants, rare animals, and native aquatic animals. And these plants and animals were transplanted and moved to ponds.

• Journal of Forest and Environmental Science
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• 제32권3호
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• pp.302-310
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• 2016

The loss and degradation in tropical forest region are some of the current global concern. Hence, these issues elevated the role of rehabilitated forests in providing ecological products and services. The information on the carbon stock is important in relation to global carbon and biomass use, but lacking from the tropical region. This paper reports the assessment of tree and soil carbon stock in a chronosequence rehabilitated tropical forest stands in Malaysia. The study site was at the UPM-Mitsubishi Forest Rehabilitation Project, UPMKB. $20{\times}20m$ plot was established each and assessed in 2009 at 1-, 10- and 19-year-old sites while an adjacent ${\pm}23-year-old$ natural regenerating secondary forest plot was established for comparison. The overall total carbon stock was in the order of 19-year-old>${\pm}23-year-old$>10-year-old>1-year-old. When forest carbon stock is low, the soil component plays an important role in the carbon storage. The forest carbon recovery is crucial to increase soil carbon stock. The variations in the carbon stock showed the different stages of the forest recovery. Species survived after 19-years of planting are potential species for carbon sequestration activities in rehabilitated forest. Human intervention in rehabilitating degraded forest areas through tree planting initiatives is crucial towards recovering the forest ecological role especially in forest carbon stock capacity.

• Journal of the Korean Wood Science and Technology
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• 제46권6호
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• pp.656-669
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• 2018

Tropical bamboo species, which have a very rapid growth rate, are considered as a promising non-timber forest product capable of exhibiting new functionality by carbonization technology. This study was conducted to compare the characteristics of carbonized bamboos from Andong (G. pseuudoarundinacea (Steudel) Widjaja), Hitam (G. atrovialacea), Tali (G. apus), Kuning (B. vulgaris Var. striata (Lodd. Ex Lindl)), and Ampel (B. vulgaris Scharad. ex Wendland), and Betung (D. asper). Each bamboo was carbonized at 200, 400, 600, 800, and $1,000^{\circ}C$, respectively, and their physical and anatomical characteristics were investigated. The result showed that the volume and weight of carbonized bamboo decreased with increasing carbonization temperature and showed the substantial changes of volume and weight between 200 and $400^{\circ}C$. The highest and the lowest density of carbonized samples were found in Ampel bamboo and Betung bamboo, respectively. The density of all carbonized bamboos tended to decrease after carbonization at 200 and $400^{\circ}C$ and relatively become constant afterwards. The carbonized bamboo prepared at 800 and $1,000^{\circ}C$ showed better refining degree. The results of the anatomical observation showed that the vascular diameter of carbonized bamboo decreased with increasing carbonization temperature, and the shrinkage in radial and tangential direction showed similar tendency. Statistical analysis showed that there was significant correlation between physical contraction and anatomical contraction. Based on the results of this study, comprehensive data about Indonesian bamboo charcoals could be obtained and it will be useful for future application studies.

• Journal of Forest and Environmental Science
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• 제36권2호
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• pp.133-142
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• 2020

Soil physical and chemical properties at three layers such as top (0-10 cm), middle (10-20 cm) and bottom (20-30 cm) layers under three different vegetation types were studied. Soil samples were collected from Acacia forest, vegetable and fallow lands of Chittagong university campus, Chittagong, Bangladesh. Results showed that sand was the dominant soil particle followed by clay and silt fractions in all soil depths under different vegetation types. Soils of fallow land showed the highest values of bulk density while forest soils had the lowest values at three depths. Acacia forest soil having lowest values of dispersion ratio (DR) is less vulnerable while fallow soil with highest DR values is more vulnerable to soil erosion. The lower pH value at all soil layers in three ecosystems represented that soils under study are acidic in nature. Contents of organic matter, total nitrogen, exchangeable cations (Ca²⁺, Mg²⁺, K⁺ and Na⁺) and cation exchange capacity (CEC) were observed higher in Acacia forest soils compared to vegetable and fallow soils. Only soils of vegetable land had higher level of available phosphorus in three layers than that of other two land covers. The study also revealed that different soil properties were observed in three different vegetation types might be due to variation in vegetation and agronomic practices.

• International Journal of Computer Science & Network Security
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• 제23권4호
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• pp.179-186
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• 2023

For the future prosperity of any society, the sound growth of children is essential. Autism Spectrum Disorder (ASD) is a neurobehavioral disorder which has an impact on social interaction of autistic child and has an undesirable effect on his learning, speaking, and responding skills. These children have over or under sensitivity issues of touching, smelling, and hearing. Its symptoms usually appear in the child of 4- to 11-year-old but parents did not pay attention to it and could not detect it at early stages. The process to diagnose in recent time is clinical sessions that are very time consuming and expensive. To complement the conventional method, machine learning techniques are being used. In this way, it improves the required time and precision for diagnosis. We have applied TFLite model on image based dataset to predict the autism based on facial features of child. Afterwards, various machine learning techniques were trained that includes Logistic Regression, KNN, Gaussian Naïve Bayes, Random Forest and Multi-Layer Perceptron using Autism Spectrum Quotient (AQ) dataset to improve the accuracy of the ASD detection. On image based dataset, TFLite model shows 80% accuracy and based on AQ dataset, we have achieved 100% accuracy from Logistic Regression and MLP models.

• Journal of Forest and Environmental Science
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• 제37권3호
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• pp.217-225
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• 2021

This study evaluated the species composition, diversity and phorophyte preference of epiphytes at the University of Port Harcourt located in southern part of Nigeria. Purposive sampling technique was used to select sites representing major avenues in the three campuses (Abuja, Choba and Delta) of the University. Data were collected on species name of phorophytes, number of individuals, diameter at breast height (dbh) and height, and species/number of epiphytes present on them. The points/sections of attachment of epiphytes on phorophytes were also recorded. A total of eight species of epiphyte belonging to six families were recorded in the study. Species diversity was higher in Abuja campus (Simpson 1-D=0.81; Shannon H=1.79), followed by Choba campus (Simpson 1-D=0.73; Shannon H=1.09) and Delta campus (Simpson 1-D=0.56; Shannon H=0.93). Species richness was highest in Abuja campus (n=8) followed by Delta campus (n=4) and Choba campus (n=3). Similarity in epiphyte species composition was highest between Choba and Delta campuses (85.71%), followed by Delta and Abuja campuses (66.67%) and lowest between Choba and Abuja campuses (54.55%). The family-Polypodiaceae, had the highest number of species (n=3). Microgramma owariensis had the highest relative abundance (27%) followed by Platycerium bifurcatum (26%) while Tillandsia utriculata and Peperomia pellucida had the least relative abundance (3%). Epiphyte abundance was weakly correlated with both the dbh and height of phorophytes. However, epiphytes were more abundant on phorophytes with rough/scaly/corky/flaky barks than on those with smooth barks. The planting of avenue tree species with rough barks is recommended to enhance the diversity of epiphytes in the study area.

• Journal of Forest and Environmental Science
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• 제32권2호
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• pp.113-119
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• 2016

The long lived iteroparous conifers produce male and female gametophyte for hundreds of years once they reach the reproductive stage, however, the production of seed is not frequent. This phenomenon of infrequent seed production in conifers is yet to be understood. An attempt to study this change in cone production in Cedrus deodara of Western Himalayas -a species reported to be mainly monoecious and rarely dioecious has been made. The observations recorded on selected trees of flowering/fruiting stage for four years at four different locations have shown the species to be dioecious with higher percentage of female trees during good seed year but with no definite or predictable pattern of reproduction in the trees. A decline in production of female trees was witnessed at all but one location immediately year after reaching the maximum (good seed year). The phenomenon of seed production has been observed to be cyclic and site specific. A change in the sexual behavior of the trees from male to female or vice-versa, male or female turning monoecious or vegetative and vegetative coming to reproductive was unpredictable.

• Journal of the Korean Wood Science and Technology
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• 제47권5호
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• pp.607-616
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• 2019

On account of the lack of education of Brazilian worker, this paper analyzed the characteristics of those professionals working in the production sector of timber houses. A sectoral survey was carried out with respective entrepreneurs to investigate the available professionals (career and contract types), evaluate the demands of skilled workers, and indicate solutions to improve the quality of labor qualification. Similarly, over 65% of sampled producers presented both direct-hired and outsourced workforce. For such contract ways, Civil Engineers and Architects were the main careers. Carpenters, Civil Engineers and Architects experienced on timber were the main sectoral demands. Timber Engineers have good potentials of service for this sector. The creation of courses on timber products can emerge as a key alternative to train people.