• Korean Journal of Remote Sensing
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• v.38 no.6_2
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• pp.1633-1641
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• 2022

Urban population concentration and indiscriminate development are causing various environmental problems such as air pollution and heat island phenomena, and causing human resources to deteriorate the damage caused by natural disasters. Urban trees have been proposed as a solution to these urban problems, and actually play an important role, such as providing environmental improvement functions. Accordingly, quantitative measurement and analysis of individual trees in urban trees are required to understand the effect of trees on the urban environment. However, the complexity and diversity of urban trees have a problem of lowering the accuracy of single tree detection. Therefore, we conducted a study to effectively detect trees in Dongjak-gu using high-resolution aerial images that enable effective detection of tree objects and You Only Look Once Version 5 (YOLOv5), which showed excellent performance in object detection. Labeling guidelines for the construction of tree AI learning datasets were generated, and box annotation was performed on Dongjak-gu trees based on this. We tested various scale YOLOv5 models from the constructed dataset and adopted the optimal model to perform more efficient urban tree detection, resulting in significant results of mean Average Precision (mAP) 0.663.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.1
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• pp.41-49
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• 2014

This study spatially assesses the impact of trees on residential rooftop solar energy potential using urban three-dimensional models derived from Light Detection and Ranging(LiDAR) data in San Francisco, California. In recent years on-site solar energy generation in cities has become an essential agenda in municipal climate action plans. However, it can be limited by neighboring environments such as shade from topography, buildings and trees. Of all these effects, the impact of trees on rooftop photovoltaics(PVs) requires careful attention because improper situation of solar panels without considering trees can result in inefficient solar energy generation, tree removal, and/or increasing building energy demand and urban heat island effect. Using ArcMap 9.3.1, we calculated the incoming annual solar radiation on individual rooftops in San Francisco and the reduced insolation affected by trees. Furthermore, we performed a multiple regression analysis to see what attributes of trees in a neighborhood(tree density, tree heights, and the variance of tree heights) affect rooftop insolation. The result shows that annual total residential rooftops insolation in San Francisco is 18,326,671 MWh and annual total light-loss reduction caused by trees is 326,406 MWh, which is about 1.78%. The annual insolation shows a wide range of values from $34.4kWh/m^2/year$ to $1,348.4kWh/m^2/year$. The result spatially maps the locations that show the various levels of impact from trees. The result from multiple regression shows that tree density, average tree heights and the variation of tree heights in a neighborhood have statistically significant effects on the rooftop solar potential. The results can be linked to municipal energy planning in order to manage potential conflicts as cities with low to medium population density begin implementing on-site solar energy generation. Rooftop solar energy generation makes the best contribution towards achieving sustainability when PVs are optimally located while pursuing the preservation of urban trees.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.217-220
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• 2005

Internal cities such as gray level been enclosed to building forest are paying a lot of efforts and expenses to change to green city toot park and street tree get put together. By the example, 'GREEN CITY of PUSAN 21' progress to decorate army facilities like the park, and to plant street trees in several places of city plan in Pusan. And urban environment that big citys of advanced nation are agreeable is making in the large park and road street trees at several places in downtown. Because price of tree for the park is very expensive, tree management system was all-important. In this paper, Motes deliver the sensor information in each tree through radio sensor network by server side. This information can use in state grasping of tree, harmful insects courtesy call etc and this system design was suggested to inform to mode of life administration scholars.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.664-669
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• 2014

This research was conducted to investigate the impact of viewing scenery and walking in the urban forest on physiological relaxation of humans. The experiment was conducted in Hanbat Arboretum located in Daejeon, and the control experiment was conducted in front of Daejeon City Hall. The subjects that participated in the experiment comprised 24 Korean male university students in their 20s (average age, $21.1{\pm}2.5years$), participated in the experiment as the subject, and these subjects were classified into three groups divided into three locations such as the pine forest in Arboretum, the pond in Arboretum, and the city. The subjects sat down and viewed scenery for 10 min, and they then walked for 15 min. Further, physiological changes were measured using indicators such as heart rate variability (HRV), blood pressure, and pulse rate. As a result, when subjects viewed scenery and walked in the urban forest, a statistically significant increase in the high frequency (HF) power of HRV and decrease in systolic pressure was observed compared with when subjects viewed scenery and walked in the city. Through this research, it was found that activities like viewing scenery or walking in Arboretum of the city are effective in increasing the physiological relaxation of the city residents.

• Proceedings of the KSRS Conference
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• 2006.03a
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• pp.131-134
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• 2006

LiDAR(Light Detection And Ranging) 데이터 처리에 있어서 건물, 자동차, 수목 등의 비지면 객체와 지면을 분류하는 필터링 과정은 DEM(Digital Elevation Model) 구축을 위해서 중요하다. 도심지역의 건물추출 등의 필터링에 관한 연구는 활발히 진행되고 있으나 국내의 경우 수목에 대한 필터링은 비교적 연구가 미흡하였다. 따라서 이 연구에서는 기존에 다루어진 몇 가지 알고리즘을 분석하고 산림지역에 활용해 봄으로써 각 필터링에 관한 장단점을 비교하였다.

• Korean Journal of Environment and Ecology
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• v.12 no.1
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• pp.30-41
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• 1998

This study analyzed urban greenspace area and vegetation structure by land use types for Kangnam-gu and Junglang-gu in Seoul different in income and building construction date. The study districts had a similar areal distribution of land use types. Residential lands accounted for about 32~37% of total area, natural lands, 19~22%, commercial and industrial lands(including transportation), 13~18%, and institutional lands, 13~17%. Greenspace covered only 20~30% of urban residential and commercial area in which human activities of living concentrate. Canopy stocking level in urban lands (all land uses except natural and agrecultural lands) was about 39% for Kangnam-gu and 50% for Junglang-gu, showing tree planting potential slightly higher in Kangnam-gu than in Junglang-gu. Woody plant cover was approximately 13%, and tree density was 3 trees/100m$^{2}$ forurban lands in both districts. The tree-age structure was largely characterized by young, growing tree population, and species diversity within a diameter class decreases as the diameter classes get larger. Urban lands of both districts had quite a similar species composition of woody plants (similarity indez of 0.70). Income and bulding construction date did not result in significant diference between the two districts in vegetation structure for urban lands. Some strategies were ezplored to solve problems found in the present greenspace structures. They included increase of biomass and greenspace area through minimization of unnecessary impervious surfaces, creation of multilayered and multiaged vegetation structures, and avoidance of intensive tree pruning and relocation of above ground utility lines.

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.441-453
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• 2015

In this paper, according to the illuminance at night with artificial lighting in downtown Seoul, trees flowering and leaf growth rate was performed as a case study to examine whether there is a difference. The illuminance was measured at 78 points on a total of 26 points, the range of illuminance were divided into three groups considering land use, Group A (plots 1-7) were 4.90 ~ 112.50 lx, Group B (plots 8 to 18) were 0.45 ~ 42.40 lx, group C (plots 19 to 26) were 0.28 ~ 22.10 lx. According to the One-way ANOVA on illuminance difference, the survey groups were classified into three groups. To survey the ratio of the flowering Prunus yedoensis and Rhododendron spp. and to survey the ratio of leaf growth Zelkova serrata, Ginkgo biloba, and Acer palmatum each 30 individuals were investigated. Rhododendron spp. to study the ratio of the flowering and Acer palmatum to study the ratio of leaf growth were determined to be useful as indicator woody species according to the correlation. The higher illuminance of night lighting is, the faster flowering and leaf growth of trees will be by correlation between the mean illuminance of each group and the flowering and leaf growth of trees. In the future, should be made a more detailed study of how much affect to the trees with some impact on the level of light pollution at night lighting.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.127-130
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• 2005

Internal cities such as gray level been enclosed to building forest are paying a lot of efforts and expenses to change to green city that park and street tree get put together. By the example, 'GREEN CITY of PUSAN 21' progress to decorate army facilities like the park, and to plant street trees in several places of city plan in Pusan. And urban environment that big cities of advanced nation are agreeable is making in the large park and road street trees at several places in downtown. Because price of tree for the park is very expensive, tree management system was all-important. In this paper, Motes deliver the sensor information in each tree through radio sensor network by server side. This information can use in state grasping of tree, harmful insects courtesy call etc and this system design was suggested to inform to mode of life administration scholars.

• Korean Journal of Remote Sensing
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• v.33 no.6_2
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• pp.1151-1157
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• 2017

Street Trees is an important object for urban environment improvement. Especially the height of the trees needs to be precisely measured as a factor that greatly influences the removal of air pollutants in the Urban Street Canyons. In this study, we extracted the height of the tree based on the stereo image using the precisely adjusted UAV Images of the target area. The adjustment of UAV image was applied photogrammetric SfM (Structure from motion) based on the collinear condition. We measured the height of the trees on the Street Canyon using stereoscopic vision on stereo plotting system. We also acquired the height of the building adjacent to the street trees and the average height of the road surface was calculated for accurate measurement of the height of each object. Through the visual analysis with the plotting operation system, it was possible to measure height of the tree and to calculate the relative height difference value with building quickly. This means that the height of buildings and trees can be calculated without making a 3D point cloud of UAV and it has the advantage of being able to utilize non-experts. In the future, further studies for semiautomatic/automation of this technique should be performed. The development and research of these technologies is expected to help to understand the current status of environmental policies and roadside trees in urban areas.

• Korean Journal of Environment and Ecology
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• v.16 no.1
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• pp.46-54
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• 2002

This study was conducted to diagnose the health of street trees with physiological characters, and to figure out the relation of physiological characters and cambial electrical resistances. Ginkgo biloba, Prunes serrulata and Salix koreensis were chosen in the Cheonan City. Soils under trees were collected to analyze dehydrogenase activities, and chlorophyll content, nitrate reductase and superoxide dismutase activities were analyzed from leaves sampled at the edge of crown in July. Cambial electrical resistances were measured in May, July and September, Soils with low dehydrogenase activity reflected the level of pollution. Chlorophyll content was the lowest in the leaves of P. serrulata at the Dongseo-street. Nitrate reductase activity of Ginkgo biloba was higher than P. serruluta and Satix koreensis. Nitrate reductase activity showed higher activity in the city than control(Independence Hall and Yonam College), but superoxide dismutase activity in the city lower than control. P. serruzatu in the Dongseo-street that cambial electrical resistance increase continuously during the growing season, showed the loss of vitality Cambial electrical resistance was negatively or positively correlated with nitrate reductase($r^2$=-0.566) and superoxide dismutase activity($r^2$=0.579). It was concluded that cambial electrical resistance might be suitable for diagnosing the tree health.