• Landscaping Tree
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• s.142
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• pp.68-70
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• 2014

• Physical Therapy Korea
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• v.30 no.2
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• pp.102-109
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• 2023

Background: While efforts have been made to differentiate fall risk in older adults using wearable devices and clinical methodologies, technologies are still infancy. We applied a decision tree (DT) algorithm using inertial measurement unit (IMU) sensor data and clinical measurements to generate high performance classification models of fall risk of older adults. Objects: This study aims to develop a classification model of fall risk using IMU data and clinical measurements in older adults. Methods: Twenty-six older adults were assessed and categorized into high and low fall risk groups. IMU sensor data were obtained while walking from each group, and features were extracted to be used for a DT algorithm with the Gini index (DT1) and the Entropy index (DT2), which generated classification models to differentiate high and low fall risk groups. Model's performance was compared and presented with accuracy, sensitivity, and specificity. Results: Accuracy, sensitivity and specificity were 77.8%, 80.0%, and 66.7%, respectively, for DT1; and 72.2%, 91.7%, and 33.3%, respectively, for DT2. Conclusion: Our results suggest that the fall risk classification using IMU sensor data obtained during gait has potentials to be developed for practical use. Different machine learning techniques involving larger data set should be warranted for future research and development.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1C
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• pp.20-25
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• 2006

In this paper, the performance of Tree-LDPC code is presented based on the min-sum algorithm with scaling and the asymptotic performance in the water fall region is shown by density evolution. We presents that the Tree-LDPC code show a significant performance gain by scaling with the optimal scaling factor which is obtained by density evolution methods. We also show that the performance of min-sum with scaling is as good as the performance of sum-product while the decoding complexity of min-sum algorithm is much lower than that of sum-product algorithm. The Tree-LDPC decoder is implemented on a FPGA chip with a small interleaver size.

• Journal of the Korean Wood Science and Technology
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• v.49 no.6
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• pp.550-565
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• 2021

This study's objective was to conduct species identification and tree-ring dating of wooden elements used in Mungyeong Juheulgwan of Joryeong (Gate No. 1). Of the 84 wooden elements evaluated, 76 were confirmed to be hard pines, 5 were soft pines, and 3 belonged to Abies spp. For tree-ring dating, cores of the wooden elements were collected using a drill, and ring-width plots of individual samples were constructed using the TSAP software. The results of performing tree-ring dating for the outermost ring of 59 hard pine wooden elements revealed the following 4 felling dates: summer of 1708-late fall of 1709, summer of 1792-early spring of 1794, late fall of 1838-early spring of 1840 and 1867, and early spring-fall of 1872. These felling dates were found to be consistent with those in the construction and repair records of the Annals of Joseon Dynasty, Juhulgwan Jungsugi, and those engraved on Juhulgwan Walls. It is believed that some of the wooden materials harvested at that time were stored and used since there was a difference of approximately10 years between the repair records and felling dates.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.3
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• pp.85-90
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• 2021

In this paper, fall detection using individual wearable devices for older people is considered. To design a low-cost wearable device for reliable fall detection, we present a comprehensive analysis of two representative models. One is a machine learning model composed of a decision tree, random forest, and Support Vector Machine(SVM). The other is a deep learning model relying on a one-dimensional(1D) Convolutional Neural Network(CNN). By considering data segmentation, preprocessing, and feature extraction methods applied to the input data, we also evaluate the considered models' validity. Simulation results verify the efficacy of the deep learning model showing improved overall performance.

• Journal of Conservation Science
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• v.38 no.2
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• pp.87-95
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• 2022

This aimed to species identification and tree-ring dating of wooden elements used in the Myeongjeong-gate of the Changgyeong-palace, Seoul, Korea. Of the 79 wooden elements evaluated, 78 were confirmed to be hard pines and one belonged to Abies spp.. Cores of the wooden elements were collected using a drill for tree-ring dating, and ring-width plots of individual samples were constructed using the TSAP software. The tree-ring dating results for the outermost ring of 58 hard pine wooden elements revealed the following felling dates: early spring of 1604-late fall of 1615, late fall of 1706-early spring of 1707, and late fall of 1828-late fall of 1834. The obtained felling dates of the 1600s and 1800s were found to be consistent with those in the construction and repair records of the Annals of Joseon Dynasty, Gwanghaegun's Diary and Changgyeonggung Yeonggeondogam Uigwe. However, the obtained felling dates of the 1700s were not consistent with those in the construction and repair records. Therefore, additional confirmation of repairs that were not included in the records was possible using tree-ring dating.

• Journal of Environmental Science International
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• v.29 no.2
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• pp.123-132
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• 2020

Seasonal changes in the CO₂ fixation rate and water-use efficiency in the leaves of six evergreen and two deciduous broad-leaved tree species on Jeju Island, Korea, were measured using a portable photosynthesis analyzer, to identify which species are most efficient in taking up CO₂ from the air. The CO₂ fixation rate was high in the deciduous species in spring and summer and decreased in fall, whereas it was high in the evergreen species in summer and fall and decreased in winter. The rate remained high in the deciduous tree Prunus yedoensis from spring to fall (> 7.1 μmol CO₂/m₂/s) and in two evergreen trees, Castanopsis cuspidata var. sieboldii and Cinnamomum camphora, in summer and fall (7.0 9.9 μmol CO₂/㎡/s). Therefore, these tree species fix atmospheric CO₂ effectively. The water-use efficiency was higher in evergreen species than in deciduous species regardless of the season. Exceptionally, it was high in the deciduous species Zelkova serrata in spring and summer (> 100 μmol CO₂/mol H₂O), suggesting that Z. serrata is a useful tree for dry conditions due to its tolerance of water stress. The regressions of the CO₂ fixation rate versus the evaporation rate and stomatal conductance were linear and non-linear, respectively. This suggests that the stomatal activity of leaves plays an important part in CO₂ fixation of plants. In conclusion, C. cuspidata var. sieboldii, C. camphora, and P. yedoensis should be planted along roads or in urban spaces for the greening of cities and mitigation of CO₂ concentrations in the air.

• The Korean Journal of Mycology
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• v.51 no.4
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• pp.511-519
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• 2023

Red pine (Pinus densiflora) is a dominant tree species in Korean forests. The diversity of endophytic fungi was investigated by isolating fungi from different parts of a red pine tree during the fall and spring seasons. One hundred and fifty-two strains of endophytic fungi were isolated and classified into 42 species belonging to 29 genera. Among these, 74 (49%), 47 (31%) and 31 strains (20%) were isolated from branches, leaves, and stems, respectively. The most frequently isolated species were Daldinia childiae and Biscogniauxia maritima (28.9% and 9.8%, respectively). D. childiae was the dominant endophytic fungus on branches (20 strains) and leaves (19 strains). B. maritima was most frequently isolated from branches. The isolation frequencies on stems of B. maritima (6 strains) and D. childiae (5 strains) were also high. Fifty-seven isolates belonging to 19 species and 17 genera were isolated in the spring, and 95 strains belonging to 35 species and 24 genera were isolated in the fall. D. childiae was the most frequently isolated fungus in both spring and fall (21 and 23 strains, respectively). B. maritima was also frequently isolated in both spring (7 strains) and fall (8 strains).

• Journal of Korean Society of Forest Science
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• v.7 no.1
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• pp.35-39
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• 1968

1. The Fall webworm, Hyphantria cunea was widely distributed ranging from Seoul to Kangnung, Yung-ju, Taegu, Iri and Kwang-ju in 1967. 2. Heavily infested tree species by the Fall webworm were Sycamore, Cherry, ash-leaved maple, poplar, and elm. 3. The average number of larval masses per damaged garden tree and roadside tree was 7.0 and 3.4 respectively. 4. Trees of 6-10m in height had most number of larval masses and were most heavily infested. 5. More larval masses were found in the median and lower parts than higher parts of the crown. 6. The ratio of damaged by second generation was 55% higher than by first generation. The ratio of damage by 3rd generation is 18% less than by first generation.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.1
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• pp.63-70
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• 2001

EZW(Embedded coding using Zero-trees of Wavelet coefficients) decreases symbol-position information using zero-trees, but threshold value fall lot raising resolution, then coding cost of significant coefficients is expensive. To avoide this fact, this paper uses quad-tree representing coefficient-position information. a magnitude of significant coefficient is represented on matrix used at EZW. the proposed algorithm is hoped for raising a coding cost.