• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2022.06a
• /
• pp.106-107
• /
• 2022

The ship type identification of the surrounding ship is important information for navigators and VTS officers since they can estimate the maneuverability and near-future route of the ships. However, it is more than frequent that the information is not provided due to transmission trouble and seafarers' unfamiliarity with AIS. Thus, this study suggests predicting ship types through the Random Forest classifier after preparing a training and test dataset that contains ship features and types. The AIS data for Ulsan coast in 2018 was used for this study. The method may provide the effect that many navigators and VTS officers discuss and share the experience of predicting ship types.

• Journal of Korean Society of Forest Science
• /
• v.110 no.4
• /
• pp.577-589
• /
• 2021

Soil seed bank community contributes to the long-term conservation of plant diversity and vegetation dynamics, and their decreasing diversity and density with soil depth provide critical perspectives (deterministic and stochastic) for understanding the community disassembly process. We analyzed changes in species composition and diversity and structuring patterns by soil layer (top and bottom), including surface vegetation, in Gwangneung Forest, a mature forest with a vegetation climate in the temperate central part of the Korean Peninsula. From two layers of soil collected with a vertical difference of 10 cm, 934 specimens of 27 families, 40 genera, 44 species, three varieties, and 47 taxa, germinated. Although species diversity and germination density decreased in most comparative characteristics, including growth type, there was no statistical significance due to large deviations. Within-group variability of species composition was similar in the upper and lower soils, as was the decline pattern in co-occurred species (ζ-diversity) and change in species retention probability. The structuring process of the community composition in the two soil layers was fitted with an exponential correlation rather than a power function, demonstrating the dominance of the stochastic process. The pattern in diversity and species turnover according to soil depth in Gwangneung Forest was discovered to be structured by stochastic random events, such as seed vertical movement rather than interaction with trait characteristics.

• Journal of the Korean Data and Information Science Society
• /
• v.23 no.6
• /
• pp.1103-1115
• /
• 2012

In this study, we studied the effect of onion on hyperlipidemia in terms of factors, such as body weight, liver weight, kidney weight, heart weight, blood glucose, total cholesterol, triglycerides, HDL-cholesterol, and LDL-cholesterol. The hyperlipidemia supplement was significantly effective on the liver weight, kidney weight, blood glucose, total cholesterol, triglycerides, and LDL-cholesterol with the fixed effect model. However, the liver weight, blood glucose, total cholesterol, and triglycerides were significantly decreased with the random effect model on the heterogeneous factors selected by Galbraith plot. The existence of publication bias was checked by using a funnel plot.

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

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.43 no.6
• /
• pp.883-896
• /
• 2023

As human activities in Korea are spread throughout the mountains, forest fires often affect residential areas, infrastructure, and other facilities. Hence, it is necessary to detect fire-damaged areas quickly to enable support and recovery. Remote sensing is the most efficient tool for this purpose. Fire damage detection experiments were conducted on the east coast of Korea. Because this area comprises a mixture of forest and artificial land cover, data with low resolution are not suitable. We used Sentinel-2 multispectral instrument (MSI) data, which provide adequate temporal and spatial resolution, and the k-nearest neighbor (kNN) algorithm in this study. Six bands of Sentinel-2 MSI and two indices of normalized difference vegetation index (NDVI) and normalized burn ratio (NBR) were used as features for kNN classification. The kNN classifier was trained using 2,000 randomly selected samples in the fire-damaged and undamaged areas. Outliers were removed and a forest type map was used to improve classification performance. Numerous experiments for various neighbors for kNN and feature combinations have been conducted using bi-temporal and uni-temporal approaches. The bi-temporal classification performed better than the uni-temporal classification. However, the uni-temporal classification was able to detect severely damaged areas.

• Journal of Korean Society of Forest Science
• /
• v.76 no.4
• /
• pp.397-409
• /
• 1987

This study was executed to analyze the user's impact on vegetation structure changes and user's psychology in Odongdo Island of Hallyo-Haesang National Park. Five sites were sampled for vegetation structure changes vi the study area according to the extent of impact observed. Also user's psychology was studied through questionnaire with the visitors and 366 answers were collected at random sampling in May, 1986. Evergreen broad-leaved forest, i.e. Machilus thunbergii, Cinnamomum camphora, and Camellia japonica forest, took possession of 32.5% (3.91ha) of total forest area when condisering the actual vegetation. Camellia japonica community covered 40.0% (4.72ha) and Sasa coreana community took possession of 41.8% (5.02ha). The area of environmental impact grade 3 and 4 area covered 44.3% of total forest area and it should be restored because self-repair seemed to be impossible. The evergreen broad-leaved forest was destoryed seriously with no younger trees in middle and lower layers by overuse impact and would be bared soon. So the preservation of autochthonous flora is required by the control of the number of users. It was shown that most of visitors come on holidays and Sunday and places which were favorably impressed were shown as the area of showing the sea and Camellia forest. Overall levels of satisfaction was comparatively low, consequently 55% of visitors were satisfied. This level of satisfaction was associated with number of users, landscape of forest and number of facilities.