• Journal of Plant Biology
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• v.14 no.4
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• pp.19-26
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• 1971

The sample stand of Pinus rigida plantation was chosen from those at the Choongnam Forest Experiment Station, Choongnam. The diameter at breast height (D) and the height of tree (H) of each tree in the sample plot of 200$m^2$ were measured yearly a from 1967 through 1969. The stand was 12.7-13.4cm in mean diameter and had a stand density of 2,150 trees per ha. The trunk, branches and leaves of each sample tree were separately weighed according to the stratified clip technique. The allometric relation between D2H and dry weight of trunk (Ws), branches (Wb) and leaves (Wl) were approximated by $$W_s=0.05917 (D^2H)^{0.837}$$ $$W_0=0.00655 (D^2H)^{0.989 }$$ $$W_l=0.04466(D^2H)^{0.690}$$ From the above, the standing crops in the sample stand was estimated to be as much as 76.7, 81.7 and 88.2 tons of dry matter, above ground, per ha in 1967, 1968 and 1969, respectively. Annual net production, as the sum of the biomass newly produced during one year, was estimated at 4.97-5.47 tons per ha per year. The respiratory and the photosynthetic rate deduced from theoretical calculations were 0.045 and 0.74kg of dry matter per kg per year. Tentative estimate of annual respiratory loss was made and annual gross production was roughly estimated at 4.4-4.7 and 10.7-12.9 tons of dry matter per ha per year. The ratio of respiratory loss to gross production was approximately 36-41:1.

• Journal of Ecology and Environment
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• v.34 no.2
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• pp.215-222
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• 2011

We evaluated the carbon (C) and nitrogen (N) status of litterfall in a natural red pine (Pinus densiflora) stand damaged by pine wilt disease in Jinju City, which was one of the areas severely affected by the disease in Korea. A significant correlation (P < 0.05) was found between tree density and basal area and the C and N status of litterfall components, but C and N status was not correlated with mean diameter at breast height in the pine wilt disease stands. Needle-litter C and N concentrations were linearly related (P < 0.05) to basal area in pine wilt disease stands. Needle-litter C concentration decreased with a decrease in damage intensity due to pine wilt disease, whereas litter N concentration increased with an increase of basal area in pine wilt disease stands. The linear regression equations developed for litterfall C and N inputs were significant (P < 0.05), with basal area accounting for 50-86% of the variation, except for cone and flower litter. The results indicated that the incidence of pine wilt disease could impact the quality and quantity of C and N in litterfall of pine stands suffering from pine wilt disease.

• Journal of environmental and Sanitary engineering
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• v.5 no.1
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• pp.14-27
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• 1990

The vegetation of Pyeongil island was ecologically investigated four times from July, 1979 to May, 1981. The vegetation of this island consisted of 80 families, 172 genera, 173 species, 21 varieties and 4 forma. Evergreen, broad-leaved trees comprised a total of 11 species including Eurya japonica Thunb. and Trachelostermum asiaticum var. intermedium Nakai. The distribution of evergreen, broad-leaved trees was very spares in this island as a whole. It may also be considered that evergreen, broad-leaved trees, such as Camellia japonica Linne (30cm-35cm in diameter at breast height), Pittosporum fobira Aiton, Eurya japonica Thunb. and Trachelostermum asiaticum var. intermedium Nakai which might have been dominant species on this island, have undergone artificial succession caused by the planting of Pinus thunbergii Parl. dominant species of today. This was due to human interferences for fuel, building, grazing and farmland use. Especially, the vegetation of this island seems to have been severely destroyed by high population density, farming rate and by rapid increase in the area of cultivated land. However, the forest of Pinus thunbergii Parlatore at Wolsong-ri is worthy of conservation. The five species of seaside plants (Ixeris dentata (Thunb.) Nakai, Rosa rugosa Thunb., Carex laticeps Clarke, Calystergia soldanella Reom. et Schult. and Phelloterus littoradis) were distributed in the vicinity of sand beaches leading to Wolsong-ri, Dongbaeg-ri and Sadong-ri.

• Journal of Biomedical Engineering Research
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• v.30 no.5
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• pp.444-451
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• 2009

Purpose: The aim of present study is to detect longitudinal alterations of mechanical characteristic determined by bone quality (microarchitecture and degree of mineralization) on femur trabecular bone due to metastatic bone tumor Materials and Methods: Each 6 female SD rats (12 weeks old, approximate 250g) were allocated in SHAM and TUMOR Group. W256 (Walker carcinosarcoma 256 malignant breast cancer cell) was injected into the right femur (intraosseous injection) in TUMOR Group, whereas 0.9% NaCl (saline solution) was injected in SHAM Group. The right hind limbs of all rats were scanned by in-vivo micro-CT to acquire structural parameters, bone mineral density, X-ray attenuation and bone mineralization distribution at 0 week and 4 weeks after surgery. Results: BMD, BV/TV and Tb.N of trabecular bone in TUMOR group were markedly decreased (26%, 11% and 23%) while those in SHAM group were significantly increased (34%, 48% and 11%) (p<0.05). BS/BV, Tb.Sp and SMI in TUMOR group were significantly increased (-16%, 38% and 2%) compared with those in SHAM group (-33%, 12% and -16%) (p<0.05). Additionally, bone mineralization in TUMOR group significantly decreased while those in SHAM group was significantly increased (p<0.05). Conclusion: It is identified that how much bone microarchitecture and mineralization are diminished due to the metastatic bone tumor. The results may be helpful to prediction of fracture risk by metastatic bone tumor.

• Journal of Ecology and Environment
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• v.33 no.1
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• pp.67-77
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• 2010

Stand structure and spatial associations of the dominant tree species in Quercus mongolica stands were investigated to understand interspecific relationships and the persistent dominance of Q. mongolica. We examined the species composition, DBH (diameter at breast height) distribution, and spatial distribution of trees (${\geq}\;2.5\;cm$ DBH) in two permanent $100\;m\;{\times}\;100\;m$ plots in Q. mongolica-dominant stands on the western part of Mt. Jiri. Ripley's K-function was used to characterize the spatial patterns and associations of dominant tree species. Q. mongolica showed a continuous and reverse-J shaped DBH distribution with clumped spatial distribution in both study sites. Q. mongolica and Abies koreana exhibited a negative association implying potential interspecific competition. The positive spatial association between Q. mongolica and Alnus hirsuta var. sibirica and Fraxinus sieboldiana were affected by site characteristics: limited habitat conditions with a large proportion of rock surface. Our results suggest that interactions among species were complex and ranged from positive to negative. Differences in stand and site characteristics and regeneration mechanisms among the species play an important role in regulating their spatial distribution patterns, while competition between individuals also contributes to spatial patterning of these communities. The high density and the early developmental stage of spatial distribution and structural characteristics of Q. mongolica and the relatively low importance values of other species in the stands imply that Q. mongolica will remain dominant in the study sites in the near future.

• Journal of Forest and Environmental Science
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• v.30 no.2
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• pp.233-242
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• 2014

Estimating above-ground biomass is important in establishing an applicable methodology of Measurement, Reporting and Verification (MRV) System for Reducing Emissions from Deforestation and Forest Degradation-Plus (REDD+). We developed an estimation model of diameter at breast height (DBH) from IKONOS-2 image that led to above-ground biomass estimation (AGB). The IKONOS image was preprocessed with dark object subtraction and topographic effect correction prior to watershed segmentation for tree crown delineation. Compared to the field observation, the overall segmentation accuracy was 64%. Crown detection percent had a strong negative correlation to tree density. In addition, satellite-based crown area had the highest correlation with the field measured DBH. We then developed the DBH allometric model that explained 74% of the data variance. In average, the estimated DBH was very similar to the measured DBH as well as for AGB. Overall, this method can potentially be applied to estimate AGB over a relatively large and remote tropical forest in Northern Borneo.

• Journal of Radiation Protection and Research
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• v.44 no.4
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• pp.149-155
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• 2019

Background: Magnetic resonance (MR) image guided radiation therapy system, enables real time MR guided radiotherapy (RT) without additional radiation exposure to patients during treatment. However, MR image lacks electron density information required for dose calculation. Image fusion algorithm with deformable registration between MR and computed tomography (CT) was developed to solve this issue. However, delivered dose may be different due to volumetric changes during image registration process. In this respect, synthetic CT generated from the MR image would provide more accurate information required for the real time RT. Materials and Methods: We analyzed 1,209 MR images from 16 patients who underwent MR guided RT. Structures were divided into five tissue types, air, lung, fat, soft tissue and bone, according to the Hounsfield unit of deformed CT. Using the deep learning model (U-NET model), synthetic CT images were generated from the MR images acquired during RT. This synthetic CT images were compared to deformed CT generated using the deformable registration. Pixel-to-pixel match was conducted to compare the synthetic and deformed CT images. Results and Discussion: In two test image sets, average pixel match rate per section was more than 70% (67.9 to 80.3% and 60.1 to 79%; synthetic CT pixel/deformed planning CT pixel) and the average pixel match rate in the entire patient image set was 69.8%. Conclusion: The synthetic CT generated from the MR images were comparable to deformed CT, suggesting possible use for real time RT. Deep learning model may further improve match rate of synthetic CT with larger MR imaging data.

• Journal of Preventive Medicine and Public Health
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• v.40 no.1
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• pp.45-50
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• 2007

Objectives : The aim of this study was to investigate the relationship between the contributions of macronutrients to the total energy intakes and Body Mass Indices (BMI, $kg/m^2$) of Korean women. Methods : We used dietary records data from 115 healthy Korean women, ages 20 and over, who completed four 3-day dietary records between February 2003 and March 2004. For the calculation of nutrients we used a dietary assessment program developed by the Korean Nutritional Society. Macronutrient intakes were estimated by averaging individual total daily intakes in four 3-day dietary records. Subjects were categorized into three Body Mass Index (BMI) groups : underweight (BMI < 20), normal (20 $\leq$ BMI < 25), and overweight (BMI $\geq$ 25) group. Results : The total energy intakes were not different among the three BMI groups. Similarly, other macronutrient intakes such as protein, fat, carbohydrate, vegetable protein, animal protein, saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids were not different. From the multivariate nutrient density model, substituting polyunsaturated fatty acid for carbohydrate was positively associated with BMI in women aged 20 to 49 ($\beta=2.31$, p<0.01). In women aged 50 and over, substituting animal protein for carbohydrate was positively associated with BMI ($\beta=0.549$, p=0.04). Conclusions : No single macronutrient was associated with BMI when all subjects were combined. However, when stratified by age, polyunsaturated fatty acid intake in younger women, and animal protein intake in older women, were positively associated with BMI. In the future, we recommend a larger study to confirm these results.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.714-720
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• 2015

Since physical and mechanical properties of wood are affected by environmental factors such as soil and climate change, this study investigated relationships between wood quality factors and stand characteristics of Castanopsis cuspidata var. sieboldii forest in the southern region of Korea, including Jeollanam-do Province and Je-ju island. The obtained results found very close relationships between physical and mechanical properties of wood and stand characteristics. The air-dried density and strength performance of woods showed a negative correlation with the diameter at breast height (DBH) while they were positively related to altitude and drainage of the forest site. And wood properties showed variations depending on the region. These results brought a conclusion that wood of Castanopsis cuspidata var. sieboldii in the southern region could be useful forest resources for timber production.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.6
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• pp.721-734
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• 2001

This paper proposed automated methods for the detection of breast mass. We analysed characteristic of the mass by using the features on mammograms. The homogeneity was used to distinguish mass and abnormal homogeneous tissue from the Cooper's ligament and multiple threshold method was used to deal with the high density candidates. By using the 8-connectivity, the first step candidates were selected. We generated the dualistic images of each candidate in which we regard the gray value as topographic height information. From these candidates, the second candidates were selected by comparing the circularity and the distribution rates. The final detection was done with the method in which we generated the template of each candidate and compared each other. From these methods, we grade the order from the candidate. We applied the algorithm to the 136 mammograms and compared to the radiologist's outlines of the leisions. The detection resulted that the sensitivity of the proposed methods was 93.38% and 97.63% FP(False positive) which we can segmented mass in the first grade in the 124 cases.