• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.561-573
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• 2023

National forests have an advantage over private forests in terms of higher investment in capital, technology, and labor, allowing for more intensive management. As such, national forests are expected to serve not only as a strategic reserve of forest resources to address the long-term demand for timber but also to stably perform various essential forest functions demanded by society. However, most forest stands in the current national forests belong to the fourth age class or above, indicating an imminent timber harvesting period amid an imbalanced age class structure. Therefore, if timber harvesting is not conducted based on systematic management planning, it will become difficult to ensure the continuity of the national forests' diverse functions. This study was conducted to determine the optimal volume of timber production in the national forests to improve the age-class structure while sustainably maintaining their economic and public functions. To achieve this, the study first identified areas within the national forests suitable for timber production. Subsequently, a forest management planning model was developed using multi-objective linear programming, taking into account both the national forests' economic role and their public benefits. The findings suggest that approximately 488,000 hectares within the national forests are suitable for timber production. By focusing on management of these areas, it is possible to not only improve the age-class distribution but also to sustainably uphold the forests' public benefits. Furthermore, the potential volume of timber production from the national forests for the next 100 years would be around 2 million m³ per year, constituting about 44% of the annual domestic timber supply.

• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.1009-1029
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• 2023

Urban trees play a vital role in urban ecosystems,significantly reducing impervious surfaces and impacting carbon cycling within the city. Although previous research has demonstrated the efficacy of employing artificial intelligence in conjunction with airborne light detection and ranging (LiDAR) data to generate urban tree information, the availability and cost constraints associated with LiDAR data pose limitations. Consequently, this study employed freely accessible, high-resolution multispectral satellite imagery (i.e., Sentinel-2 data) to estimate fractional tree canopy cover (FTC) within the urban confines of Suwon, South Korea, employing machine learning techniques. This study leveraged a median composite image derived from a time series of Sentinel-2 images. In order to account for the diverse land cover found in urban areas, the model incorporated three types of input variables: average (mean) and standard deviation (std) values within a 30-meter grid from 10 m resolution of optical indices from Sentinel-2, and fractional coverage for distinct land cover classes within 30 m grids from the existing level 3 land cover map. Four schemes with different combinations of input variables were compared. Notably, when all three factors (i.e., mean, std, and fractional cover) were used to consider the variation of landcover in urban areas(Scheme 4, S4), the machine learning model exhibited improved performance compared to using only the mean of optical indices (Scheme 1). Of the various models proposed, the random forest (RF) model with S4 demonstrated the most remarkable performance, achieving R² of 0.8196, and mean absolute error (MAE) of 0.0749, and a root mean squared error (RMSE) of 0.1022. The std variable exhibited the highest impact on model outputs within the heterogeneous land covers based on the variable importance analysis. This trained RF model with S4 was then applied to the entire Suwon region, consistently delivering robust results with an R² of 0.8702, MAE of 0.0873, and RMSE of 0.1335. The FTC estimation method developed in this study is expected to offer advantages for application in various regions, providing fundamental data for a better understanding of carbon dynamics in urban ecosystems in the future.

• Journal of the Korean Association of Geographic Information Studies
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• v.27 no.2
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• pp.78-95
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• 2024

For the establishment and comparison of environmental plans across various domains, considering climate change and urban issues, it is crucial to build spatial data at the regional scale classified with consistent criteria. This study mapping the Local Climate Zone (LCZ) of Changwon City, where active climate and environmental research is being conducted, using the protocol suggested by the World Urban Database and Access Portal Tools (WUDAPT). Additionally, to address the fragmentation issue where some grids are classified with different climate characteristics despite being in regions with homogeneous climate traits, a filtering technique was applied, and the LCZ classification characteristics were compared according to the filtering radius. Using satellite images, ground reference data, and the supervised classification machine learning technique Random Forest, classification maps without filtering and with filtering radii of 1, 2, and 3 were produced, and their accuracies were compared. Furthermore, to compare the LCZ classification characteristics according to building types in urban areas, an urban form index used in GIS-based classification methodology was created and compared with the ranges suggested in previous studies. As a result, the overall accuracy was highest when the filtering radius was 1. When comparing the urban form index, the differences between LCZ types were minimal, and most satisfied the ranges of previous studies. However, the study identified a limitation in reflecting the height information of buildings, and it is believed that adding data to complement this would yield results with higher accuracy. The findings of this study can be used as reference material for creating fundamental spatial data for environmental research related to urban climates in South Korea.

• Journal of dental hygiene science
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• v.9 no.3
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• pp.257-263
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• 2009

The objective of this study is to establish the number of erupted $1^{st}$ molar, the age. sex and somatic measures of weight and height in population of Chungcheongnam-do, South Korea based cross sectional study. The consistent and complete data were obtained from 441 children with age of six. SPSS 12.0 was used for various statistical analyses including descriptive, cross tabulation, correlation and regression. Results demonstrates that variation of the number of the erupted $1^{st}$ molar was explained by age($x^2$(df)=117.68), height($x^2$(df=59.74) and weight($x^2$(df)=31.69) of children (P<.001). The study also showed the strong correlation among erupted $1^{st}$ molar rate, age, height and weight (p<.01). Numerical values of correlation among those are following: r = .45 between Erupted $1^{st}$ molar rate and age; r = .31 between erupted $1^{st}$ molar rate and height; r = .24 between erupted $1^{st}$ molar rate and weight; r = .40 between age and weight; r = .24 between age and height; r = .54 between height and weight. It was concluded that above variables influences one another and the age of the children is the greatest variable that influences the number of erupted $1^{st}$ molar, followed by height and weight of the children.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.1
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• pp.13-18
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• 2009

Accurate solar radiation data are critical to evaluate major physiological responses of plants. For most upland crops and orchard plants growing in complex terrain, however, it is not easy for farmers or agronomists to access solar irradiance data. Here we suggest a simple method using a sun-slope geometry based topographical coefficient to estimate daily solar irradiance on any sloping surfaces from global solar radiation measured at a nearby weather station. An hourly solar irradiance ratio ($W_i$) between sloping and horizontal surface is defined as multiplication of the relative solar intensity($k_i$) and the slope irradiance ratio($r_i$) at an hourly interval. The $k_i$ is the ratio of hourly solar radiation to the 24 hour cumulative radiation on a horizontal surface under clear sky conditions. The $r_i$ is the ratio of clear sky radiation on a given slope to that on a horizontal reference. Daily coefficient for slope correction is simply the sum of $W_i$ on each date. We calculated daily solar irradiance at 8 side slope locations circumventing a cone-shaped parasitic volcano(c.a., 570m diameter for the bottom circle and 90m bottom-to-top height) by multiplying these coefficients to the global solar radiation measured horizontally. Comparison with the measured slope irradiance from April 2007 to March 2008 resulted in the root mean square error(RMSE) of $1.61MJ\;m^{-2}$ for the whole period but the RMSE for April to October(i.e., major cropping season in Korea) was much lower and satisfied the 5% error tolerance for radiation measurement. The RMSE was smallest in October regardless of slope aspect, and the aspect dependent variation of RMSE was greatest in November. Annual variation in RMSE was greatest on north and south facing slopes, followed by southwest, southeast, and northwest slopes in decreasing order. Once the coefficients are prepared, global solar radiation data from nearby stations can be easily converted to the solar irradiance map at landscape scales with the operational reliability in cropping season.

• Journal of Haehwa Medicine
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• v.2 no.2
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• pp.219-246
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• 1993

In 1991, Obesity rate of South Korea has reached to 18.7%. Because of economical development, the pattern of diet is exchanged from carbohydrate to rich protein and fat. The more problem is not only obesity of adult but also one of little child. Obesity is induced to diabetes mellitus, hypertension, artherosclerosis, hyperlipoidemia. heart and C.V.A disease, etc. In Woman, special important ploblem is the complex of beauty about Woman's figure. In Oriental Medicine, the factor of obesity is mainly regarded as dampness. And there are many treatments and methods to body weight loss, but obesity patients dislike to use them because of their side effects and inconvenience, intolerance. Now ear acupuncture is applied on so many disease because of its easy handly, non-side effect and high efficiency in clinics. Here obesity acupuncture is used to ear and whole body acupuncture. Because they react eachother for lack point. Therefore, in order to investigate the effect of obesity acupuncture and develop non-drug, non-starvation etc, we analyzed 453 the cases of body weight loss patients treated with ear and whole body acupuncture in Oriental Medicine Hospital of Jeon-Ju Woo-Sug University from April.1.1992. to March.17. 1993. The results were summarized as follows. 1. Distribution of sex ; male (4.4%), Female(95.6%) 2. Distribution of age in descending order ; 30s, 20s, 40s, 10s, 50s, below 10s, abowe 60s. The 20s-30s are group made up 60.7% of the group. 3. Distribution of occupation in descending order; housewife, student, service, salaried, merchant, teacher, farmer, inoccupation. 4. Distribution of human coporal constitution in descending order : Tae-Eum-In, So-Eum-In, So-Yang-In. 5. Distribution of body height and weight, 155-164cm ; 71.1%, 60-70kg, 74.6% are majority. 6. Distribution of weight variation, 2-6kg(71.0%) is majority, also 13-14kg(0.4%). 7. Distribution of duration in descending order ; 1-3 years, 3-6 years, 1-12months, above 10 years but in success, 1-12 months, 1-3 years, 3-6 years, above 10 years. Therefore, we know that the shorter duration of obesity is, the more loss of body weight. 8. Past experiences to body weight loss; Yes(69.5%), No(30.5%). The success rate accordant with the past temporary experiences shows that the cases without experience is higher than the ones with experience. 9. In distribution of times(treatments), 10 times is top. The rate of body weight loss is the highest in 14 times. Therefore, I think that one would need at least 10 times. in order lose body weight 10. Distribution of body weight variation in treatments times is at 2 times(3-4kg loss), and surprisingly is 14kg loss at above 15 times. 11. Distribution of symptoms improvement, in descending order ; heavy sense in body, dec. of appetite, inc.of exercise, lumbago, edema, knee pain, inc.of urine, inc. of fullness sense, thirsty, disease of gynecology, white tung, chest burning, heart burning, dec.of tobacco, drink taste. motion sickness, allergy, water eczema, arthma, belching. 12. Distribution of snack; Yes(87.4%), No(78.6%) 13. Distribution of exercise; Yes(21.4%), No(78.6%) 14. Distribution of sleeping times, above 7 hours(79.0%) 15. Distribution of the reason to body loss, the complex of beauty(68.7%) is top. 16. Distribution of side effect in obesity acupuncture, constipation (17.4%) is top. 17. Distribution of method in body weight loss ; dietary treatment (31.1%), sauna(26.7%), exercise(19.7%), the center of body weight loss (15.0%) herb-med and starvation treatments (5.1%), hand-finger acupuncture (hand-foot acupuncture) is 1.6%, diet pill(0.3%), etc(0.6%).

• Journal of Life Science
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• v.22 no.5
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• pp.642-649
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• 2012

The southern coast of Korea is important for the ark shell ($Scapharca$ $broughtonii$) aquaculture, but the productivity was rapidly reduced during the previous decade by mass mortality. To overcome this economic loss, investigations only focused on environmental factors, and microbiological researches were performed insufficiently. In this study, two sites (Gangjin and Jinhae bay) were selected for their high and low rate of mortality, respectively, and the existence of microflora from underwater sediments in the bodies of $S.$ $broughtonii$ was analyzed. We screened the whole body of each sample and chose unique colonies, which exhibit alpha- and beta-hemolytic activity, for identification. The microflora in $S.$ $broughtonii$ was less variable than sediments, and restricted species were isolated. We identified 17 genera of 88 species and 16 genera of 64 species from the two bays, respectively. A major proportion was comprised of $Bacillus$ species, with the $Bacillus$ $cereus$ group being the most common species among the $Bacillus$ strains, while $Paenibacillus$, $Lynsilbacillus$, and $Vibrio$ species were the second most abundant species. At the genus level, there were no significant microbial differences between the two coastal regions. 64 species were isolated from rare site (Jinhae bay), but more species (88) with greater variety were isolated from the frequent site (Gangjin bay). Therefore, it was assumed that the cause of mass mortality lay in the difference in specie-level diversity, and conducting investigations on the diagnosis of pathogenic species by challenging tests using isolated unique species.

• Journal of agricultural medicine and community health
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• v.39 no.1
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• pp.1-13
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• 2014

Objective: The objectives were to estimate the rate of the injury in the elderly over the past year and to identify factors related to injury in the elderly in South Korea. Method: Using data from the 2008 Community Health Survey, 43,049 elderly persons, aged 65 years and older, were selected as study subjects. Their experience of injury during the past year and other variables, including socio-demographic factors, health-related factors, and diagnosed chronic diseases, were used. The chi-squared test and multiple logistic regression analysis with weighted analysis were conducted and statistical significance was set at p<0.05. Result: The rate of injury in the elderly during the past year was 5.1%. The most common types of the injury were falling/slipping down and traffic accidents. Factors related to injury in the elderly were living alone, current drinking, depression, poor self-rated health, stroke, and osteoporosis. Living alone (odds ratio 1.23, 95% CI: 1.05-1.45), current drinkers (OR 1.19, 95% CI: 1.05-1.35), poor self-rated health (OR 1.72, 95% CI: 1.43-2.08), depression (OR 1.23, 95% CI: 1.17-1.68), and history of stroke (OR 1.40, 95% CI: 1.17-1.68), and history of osteoporosis (OR 1.45, 95% CI: 1.26-1.66) were related to an increased risk of injury. Conclusions: Intervention programs that consider the risk factors related to injury should be developed and implemented to decrease and prevent injuries in the elderly.

• Journal of the Korean Geographical Society
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• v.43 no.4
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• pp.449-465
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• 2008

Coastal lagoon has experienced a natural geomorphic development process which has been aggraded after the climax of transgression in Holocene. This study estimates superiority on landscape conservation of lagoons and degree of landscape changes during the 20th century as conservation ratios of area and shore length, and analyzes the causes of the changes and classifies the lagoons based on the data by case study of the major 7 coastal lagoons(Hwajinpo, Songjiho, Gwangpoho, Yeongrangho, Maeho, Hyangho, and Gyeongpoho) in the middle East Coast of the Korean Peninsular. Based on the conservation ratios of area and shore length, the areal change is in order of Songjiho($0.56km^2$, 92%), Hwajinpo($2.06km^2$, 90%), Yeongrangho($0.96km^2$, 86%), Hyangho($0.32km^2$, 76%), Gyeongpoho($0.90km^2$, 52%), Maeho($0.14km^2$, 50%), and Gwangpoho($0.07km^2$, 32%), and the shore length change is in order of Hwajinpo(11.90km, 100%), Hyangho(3.34km, 90%), Yeongnangho(7.21km, 89%), Gyeongpoho(7.11km, 79%), Songjiho(5.56km, 79%), Gwangpoho(1.16km, 62%), and Maeho(2.16km, 58%). Therefore, the characteristics of landscape changes of the lagoons in the study area can be represented in order of Hwajinpo(Al), Hyangho(A2), Yeongrangho(A3), Songjiho(A4), Gyeongpoho(B4), Gwangpoho(B5), Maeho(B6). Serious process for land use and industrial development has changed landscape around lagoons decreasing the area of coastal plains dramatically up to this century. Because small lagoons such as Maeho and Gwangpoho have experienced severe transformation and destruction, and Gyeongpoho was transformed into artificial lake for urbanization and tourism, they show dramatic landscape change.

• Korean Journal of Remote Sensing
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• v.36 no.5_3
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• pp.1109-1123
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• 2020

In South Korea with forest as a major land cover class (over 60% of the country), many wildfires occur every year. Wildfires weaken the shear strength of the soil, forming a layer of soil that is vulnerable to landslides. It is important to identify the severity of a wildfire as well as the burned area to sustainably manage the forest. Although satellite remote sensing has been widely used to map wildfire severity, it is often difficult to determine the severity using only the temporal change of satellite-derived indices such as Normalized Difference Vegetation Index (NDVI) and Normalized Burn Ratio (NBR). In this study, we proposed an approach for determining wildfire severity based on machine learning through the synergistic use of Sentinel-1A Synthetic Aperture Radar-C data and Sentinel-2A Multi Spectral Instrument data. Three wildfire cases-Samcheok in May 2017, Gangreung·Donghae in April 2019, and Gosung·Sokcho in April 2019-were used for developing wildfire severity mapping models with three machine learning algorithms (i.e., Random Forest, Logistic Regression, and Support Vector Machine). The results showed that the random forest model yielded the best performance, resulting in an overall accuracy of 82.3%. The cross-site validation to examine the spatiotemporal transferability of the machine learning models showed that the models were highly sensitive to temporal differences between the training and validation sites, especially in the early growing season. This implies that a more robust model with high spatiotemporal transferability can be developed when more wildfire cases with different seasons and areas are added in the future.