• Journal of agriculture & life science
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• v.46 no.1
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• pp.83-90
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• 2012

This study was undertaken to analyze 1) the growth characteristics for the optimal planting density and 2) reached ages of sap tapping for the planting timing of Acer okamotoanum in natural and plantation stand. Soil in natural stand was significantly more fertile than that of plantation stand. Early growth of A. okamotoanum in plantation stand was affected by planting density. Results showed that there was a positive relationship between the DBH and crown width in both natural and plantation stands. Reached ages by DBH were no significant difference in natural stands. Reached ages on DBH 10 cm were approximately 19 and 9 in natural and plantation stands, respectively.

• Archives of Plastic Surgery
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• v.49 no.1
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• pp.50-54
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• 2022

Background In recent years, the number of people riding stand-up electric scooters in South Korea has increased rapidly. This study analyzed the facial injury patterns associated with stand-up electric scooter-related trauma in patients who visited our emergency center. Methods In this retrospective review, we collected data from patients who had visited our emergency center for stand-up electric scooter-related trauma between January 1, 2018 and December 31, 2020. Results The average age of the patients was 26.7 years. Of the 73 patients, 47 were male and 26 were female, highlighting a male predominance. Seven patients were injured after alcohol consumption. None of the patients had worn helmets. Additionally, upon comparing the frequency of facial injuries according to the quarter of the year, the facial injury rate was higher in the second and third quarters than in the first and fourth quarters. Facial soft tissue injuries were classified into facial cosmetic subunits and analyzed according to their location. The highest number of injuries was on the chin (n=18, 20.9%). Of the 73 patients with stand-up electric scooter-related facial injuries, 16 had acute facial osseous fractures. The commonest acute facial osseous fractures were those of the orbit (n=7, 26.9%). Conclusions The patterns of facial trauma reported here can be helpful for quickly evaluating and treating patients with facial trauma related to stand-up electric scooters. Additionally, people riding stand-up electric scooters should be aware of the risks associated with facial trauma and the importance of wearing protective devices, such as helmets and masks.

• Journal of Internet of Things and Convergence
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• v.9 no.1
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• pp.57-64
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• 2023

In this paper, we propose a smart umbrella stand based on the Internet of Things (IoT) that helps people to pack their umbrellas more easily. The proposed smart umbrella stand offers three functions. First, it receives weather information, and a hidden umbrella handle will automatically become visible when it rains, making it easier to grab. Second, the smart umbrella stand is equipped with a heated air system, allowing it to effectively dry umbrellas that have become wet due to rain. This makes it more convenient for users to dry and store their rain-soaked umbrellas. Third, the smart umbrella stand enables users to monitor its current status, track weather conditions, and monitor the water level in the rain gutter through a dedicated application. The proposed smart umbrella stand aims to bring convenience to daily life by making it more convenient to carry an umbrella on rainy days or days with a high probability of rain.

• Journal of Korean Society of Forest Science
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• v.105 no.3
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• pp.294-302
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• 2016

This study was conducted to evaluate aboveground tree biomass and nutrient (C, N, P, K, Ca, and Mg) response of tree components by high (1,933 trees $ha^{-1}$) and low (1,200 tree $ha^{-1}$) stand densities in a 27-year-old Quercus glauca plantation. The study site was located in Goseong county, Gyeongsangnam-do, southern Korea. Total 12 trees (6 high and 6 low stand densities) were cut to develop allometric equations and to measure nutrient concentration of tree components. Stand density-specific allometric equations in the high and low stand densities were significant (P < 0.05) in tree components with diameter at breast height (DBH). Also, generalized allometric equations could be applied to estimate tree biomass regardless of the difference of stand density because of no significant effect on slope of stand density-specific allometric equations. Aboveground tree biomass estimated by the allometric equations was significantly higher in the high stand density (177 Mg $ha^{-1}$) than in the low stand density (114 Mg $ha^{-1}$). However, nutrient concentration of tree components was not significantly affected by the difference of stand density. Nutrient stocks in tree components were not significantly between the high stand density and the low stand density, except for the N and P stocks of stem wood. These results indicate that aboveground tree biomass could be significantly affected by stand density, but nutrient concentration among the tree components was not affected by the difference of stand density in a Quercus glauca plantation.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.518.1-518
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• 2001

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.6
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• pp.43-48
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• 2002

This study was carried out to clarify the change characteristics of stream water quality by land-use of forest from July to September, 2000 in three stands(Pinus densiflora, Castanea crenata (I), Castanea crenata (II) stand) of Jeongpyeong-ri, Jinju-si, Gyeongnam. The mean pH of rainfall results in acid rain of 5.3. The pH of stream water in three stands was high in order of Pinus densiflora (pH 6.59), Castanea crenata (II)(pH 6.53) and Castanea crenata (I) stand(pH 6.47). The electrical conductivity of stream water was high in order of Castanea crenata (I), Pinus densiflora and Castanea crenata (II) stand. Cations contents of three stands in stream water were high in order of $Ca^{2+}$, $Na^{2+}$, $Mg^{2+}$, $K^+$ and ${NH_4}^+$. But anions of stream water in Pinus densiflora stand and Castanea crenata (II) stand were high in order of ${SO_4}^{2-}$, $Cl^-$ and ${NO_3}^-$. In Castanea crenata (I) stand cations of stream water were high in order of ${NO_3}^-$, ${SO_4}^{2-}$ and $Cl^-$. The level of pH, ${NH_4}^+$, ${NO_3}^-$, $Cl^-$ and ${SO_4}^{2-}$ of stream water in Pinus densiflora stand and Castanea crenata (II) stand reached within the level of domestic use standard for drinking water But the level of ${NO_3}^-$ of stream water in Castanea crenata (I) stand was higher than that of domestic use standard. Therefore, non-point sources like forest watersheds which are fertilizer application lands should be taken to the appropriate mitigation measures.

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.132-138
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• 2016

The objectives of this study were to infer the parameters of forest stand growth functions of STEMS for Cryptomeria japonica stands of Jeju Hannam Experimental Forest, Korea Forest Research Institute, and to investigate the effects of thinning regimes on the patterns of stand growth and carbon absorption. The forest stand growth functions for the potential diameter growth, modifier, crown ratio and mortality are the major ones composing the independent-tree/distance-free forest stand growth simulator, STEMS. The parameters were inferred using the sets of growth data obtained from stem analyses of 39 trees, chosen from 13 sample plots of the forest stands. The effects of thinning regimes on the patterns of stand growth and carbon absorption were investigated by simulating the stand growth patterns of the case study stand with 3 different thinning regimes: no-thinning, early thinning with low intensity and late thinning with high intensity using the simulator. According to the results of the analyses, the different thinning regimes cause significant effects on the growth patterns of average DBH, average height, diameter distribution and stand volume as well as the amount of carbon absorptions.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.515-521
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• 2013

The objective of this study was to estimate the changes of stand structure before and after applying the three different silvicultural treatments such as selection cutting system, two-storied system, and shelterwood system. This study has been conducted in the natural deciduous forests in Pyeongchang of Gangwon Province, Korea. Nine permanent sampling plots of 0.09 ha were established in the forests and each of the three silvicultural treatments was applied to three sampling points. Some tree variables were measured in each stand before and after the silvicultural treatments were applied. With these data, stand attributes were estimated in each stand before and after applying the silvicultural treatments. In this study, a competition index was used to analyze the differences among structures of stands managed by three different silvicultural treatments. Hegyi's distance-dependent competition index was estimated and compared to analyze the differences of stand structures among the stands before and after silvicultural treatments. A method using a height angle $50^{\circ}$ from the base of the subject tree was adopted as the selection method of competitor trees. Duncan's multiple range test and t-test were then employed to statistically analyze the difference of stand structure among the stands. The results revealed that competition status among trees in the stand seems to be improved after applying the silvicultural treatments. There are significant differences in the competition index between before and after silvicultural treatments for each stand. According to the evaluation of competition index, it was confirmed that spatial structure of the stands was improved by applying the silvicultural treatments.

• Journal of Korean Society of Forest Science
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• v.103 no.2
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• pp.175-181
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• 2014

This study was conducted to evaluate stand density-specific and generalized allometric equations, and biomass expansion factors (BEFs) for two stand densities (high density of 47-year-old: $667tree{\cdot}ha^{-1}$; low density of 49-year-old: $267tree{\cdot}ha^{-1}$) of Cryptomeria japonica plantations in Namhae-gun, located in the southern Korea. Biomass in each tree component, i.e. foliage, branch, and stem, was quantified by destructive tree harvesting. Allometric regression equations of each tree component were significant (P<0.05) with diameter at breast height (DBH) accounting for 80-96% of the variation except for branch biomass in high density or foliage and cone biomass in low density. Generalized allometric equations can be used to estimate the biomass of C. japonica plantations because the slopes of allometric equations were not significantly different by the stand density. The biomass expansion factors (BEFs) were significantly lower in the high stand density (1.33) than in the low stand density (1.50). The results indicate that BEFs were affected by different stand density, while allometric equations were little related to the stand density.

• Journal of Wetlands Research
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• v.10 no.3
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• pp.9-26
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• 2008

To clarify the reed (Phragmites australis) stand's effects on the sediment properties and its increasing pattern, breaths of reed stands in 1999 and 2000, and sediment properties - water, salt, organic matter, sulphur, nitrogen, carbon and hydrogen contents - along th depth at the three stands in 2007 were surveyed at Suncheon Bay. Regardless of reed stand, the more distance from the land was long, the more water and salt contents of sediment were high. Organic matter content of sediment was high and increased with the reed biomass at the upper layer but low regardless of biomass at the lower layer. Sulphur content of sediment was higher at old reed stand (0.33%) than at new stand (0.21%) or non-vegetated stand (0.23%). Carbon, nitrogen and hydrogen contents of sediment were similar at three stands in mean values. However, their contents were high at upper layer and low at lower layer in a stand. Therefore, the changing pattern of organic matter content with the depth was similar to but not coincided to the inorganic nutrients' ones. The mean breadth of reed stands increased $2.33{\pm}0.73m$ in 1999 and $3.65{\pm}1.64m$ in 2000. However, the increase of reed stands' breadth a year varied along the direction, year or stands, so that there was not a trend in increasing pattern. It was thought that this increasing pattern made the reed's patch round. The height and density of reed shoot in newly formed stand decreased with the distance from the center of stand. In the newly formed peripheral area of a reed stand, the shoot density was not related with the land (north) or sea (south) direction, however, the shoot height was higher in the sea (south) than in the land (north) direction.