• Journal of Korean Society of Forest Science
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• v.107 no.3
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• pp.245-257
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• 2018

The study was carried out to discover the forest vegetation structure in Hongdo Island, Jeonnam province. Vegetation data were collected by total of forty one quadrate plots using Z-M phytosociological method from June to August in 2017, and analyzed by vegetation classification, mean importance value and species diversity. As a result of vegetation type classification, Castanopsis sieboldii community group was classified at a top level of vegetation hierarchy. In the level of community, it was classified into Neolitsea sericea community and Carpinus turczaninowii community. N. sericea community was subdivided into Ficus erecta group(Vegetation unit 1) and Arisaema ringens group(VU 2). C. turczaninowii community was subdivided into Fraxinus sieboldiana group(VU 3) and C. turczaninowii typical group(VU 4). Therefore, it was classified into total of four vegetation units(one community group, three communities and four groups). As a result of mean importance value, Castanopsis sieboldii was the highest in VU 1, VU 2, VU 4, and C. turczaninowii in VU 4, respectively. In case of species diversity, VU 3 showed the highest among four units in species diversity index. In conclusion, the forest vegetation of Hongdo Island was classified into four units and seven species groups. Hongdo Island could be conclusively managed by community ecological approach for the units and groups. Also it was considered that a research for the succession to the evergreen broad-leaved forest should be more intensively proceeded near future.

• Korean Journal of Environment and Ecology
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• v.34 no.6
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• pp.573-588
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• 2020

The study investigated the forest vegetation structure of Kongju National University Forests in the vicinity of Seokjangri-dong to provide the information needed for efficient use and management. It conducted a Z-M phytosociological vegetation survey in 60 quadrate plots in August 2019 and generated the actual vegetation map by analyzing the physiognomic community classification and mean importance value. The physiognomic community classification showed five vegetation community types: Quercus acutissima community, Pinus densiflora community, Quercus variabilis community, Pinus rigida community, and Quercus serrata community. The relative importance value in the Q. acutissima community was 31.4% for Q. acutissima, 9.6% for Prunus spp., and 9.0% for Q. variabilis. In the P. densiflora community, it was 24.9% for P. densiflora, 12.4% for Q. acutissima, and 11.5% for Q. serrata. In the Q. variabilis community, it was 25.3% for Q. variabilis, 9.8% for Prunus spp., and 8.5% for Q. acutissima. In the P. rigida community, it was 28.4% for P. rigida 28.4%, 10.0% for Q. acutissima, and 9.3% for P. densiflora. In the Q. serrata community, it was 27.0% for Q. serrata, 11.3% for Q. aliena, and 11.5% for Styrax japonica. The actual vegetation map based on the uppermost dominant species to identify the forest vegetation's spatial distribution characteristics indicated that the natural vegetation covered the most with 87.5%, the number of vegetation patches was 87, and the average area per patch was 1.46ha.

• Korean Journal of Environment and Ecology
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• v.23 no.1
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• pp.78-89
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• 2009

As 'design for all' and 'adaptable design', universal design is highly demanded to be adopted in neighborhood forest trail. The research areas were Mt. Doeum in Pohang, Gyeongsangbuk Province and Mt. Anma in Chuncheon, Gangwon Province which were equipped based on 7 principles of universal design. The purpose of this research is providing baseline data for effective formulation of forest trail using universal design through visitors' evaluation on forest trail facilities by importance-performance analysis. Visitor's evaluation was achieved through questionnaire survey, and total 247 pieces of subjects were used for the analysis, 114 pieces from Mt. Doeum in Pohang and 113 pieces from Mt. Anma in Chuncheon. The residential areas of the respondents were mainly near each mountain - Mt. Doeum and Mt. Anma. According to the responses, nature study and education were the biggest reasons for the respondents' visits to Mt. Doeum, and so was the health to Mt. Anma, which are representative types of visiting behavior to nearby forest trails. The mean of importance was shown to be 3.87 while that of performance was 4.04, being a little higher than importance's, in importance-performance analysis of Mt. Doeum. This result suggests that the responders placed positive value on the forest trail applying universal design. It is necessary to improve the safety and convenience of guidance-safety handrail, make information sign easy to understand, and introduce an interpretive sign meeting the visiting purposes of visitors. Also, the management to make the road surface flat is in demand for the accessibility to forest trail. The mean of importance was 3.92 and that of performance was 3.99 in Mt. Anma, which suggests the necessity of improvement in safety of pavement material and boundary safety facilities.

• Journal of Environmental Health Sciences
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• v.20 no.1
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• pp.28-38
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• 1994

The objective of this study were to measure concentrations of indoor pollutants in public transportation systems to provide importance of indoor air quality in transportation systems to policy makers. Indoor air quality of the pollutants (CO, CO$_2$, PM-10) and environmental sources (temperature, humidity) were measured at subway, seat-type bus, and city-type bus in the Seoul area from April to September 1992. The same pollutants and environmental sources were also measured at selected bus stops and subway stations during October 1991-September 1992. The mean concentrations of indoor pollutants in the public transportation systems were showed 115.5 $\mu$g/m$^3$ in PM-10, 6.8 ppm in CO, and 2167.9 ppm in CO$_2$, respectively. The mean values of PM-10 and CO showed below the U.S. 24 hour standard value of PM-10 and the Korea ambient CO standard, while the mean concentrations of CO$_2$ exceeded the Korea CO$_2$ standard. The highest levels of indoor concentration at public transportation systems were PM-10 of 134.6 $\mu$g/m$^3$ in the subway, CO of 8.9 ppm in the city-type bus, CO$_2$ of 2,511.1ppm in seat-type bus, respectively. The results showed that indoor air quality in bus and subway seemed likely to be affected by number of passengers and outdoor air infiltrated from exhausted gases of automobiles.

• Wind and Structures
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• v.26 no.2
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• pp.99-114
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• 2018

Due to shortage of land and architectural aesthetics, sometimes the buildings are constructed as unconventional in plan. The wind force acts differently according to the plan shape of the building. So, it is of utter importance to study wind force or, more specifically wind pressure on an unconventional plan shaped tall building. To address this issue, this paper demonstrates a comprehensive study on mean pressure coefficient of 'E' plan shaped tall building. This study has been carried out experimentally and numerically by wind tunnel test and computational fluid dynamics (CFD) simulation respectively. Mean wind pressures on all the faces of the building are predicted using wind tunnel test and CFD simulation varying wind incidence angles from $0^{\circ}$ to $180^{\circ}$ at an interval of $30^{\circ}$. The accuracy of the numerically predicted results are measured by comparing results predicted by CFD with experimental results and it seems to have a good agreement with wind tunnel results. Besides wind pressures, wind flow patterns are also obtained by CFD for all the wind incidence angles. These flow patterns predict the behavior of pressure variation on the different faces of the building. For better comparison of the results, pressure contours on all the faces are also predicted by both the methods. Finally, polynomial expressions as the sine and cosine function of wind angle are proposed for obtaining mean wind pressure coefficient on all the faces using Fourier series expansion. The accuracy of the fitted expansions are measured by sum square error, $R^2$ value and root mean square error.

• Journal of the Economic Geographical Society of Korea
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• v.9 no.3
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• pp.358-378
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• 2006

This study aims to examine seven factors and forty-two selection attributes of Seoul as an Exhibition and Convention Destination Site through the Importance-Performance Analysis(IPA) from the Exhibition and Convention Planner. The result of this study shows these three conclusions. First, according to the result of the Importance-Performance Analysis(IPA) of the forty-two selection attributes of an Exhibition and Convention Destination Site, thirteen attributes were placed on the right top area(Keep Up the Good Work), four attributes were placed on the right bottom area(Possible Overkill), five attributes were located on the left top area(Concentrate Here), and the other twenty attributes were located on the left bottom area(Low Priority). Second, the Importance-Performance Analysis(IPA) of seven factors in an Exhibition and Convention Destination Site reveals that the factors in the right top area(Keep Up the Good Work) of high importance and high performance were "Exhibition and Convention Center Facilities", "Exhibition and Convention Fee", and "Exhibition and Convention Center Accommodation Capacity". And the one factor located on the left top area(Concentrate Here) of high importance and low performance was "Exhibition and Convention Destination Regional Space", while the other factors of "Exhibition and Convention Center Management", "Exhibition and Convention Destination Tourism Space" and "Exhibition and Convention Destination Leisure Activity Space" were placed on the left bottom area(Low Priority) of low importance and low performance. Third, the difference of the mean value of the Importance and Performance on Seoul as an Exhibition and Convention Destination Site has been revealed that the performance of the attributes was lower than the importance of the attributes because forty attributes have described all plus(+) except two attributes.

• Journal of the Korean Dietetic Association
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• v.2 no.2
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• pp.168-180
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• 1996

This study was accomplished to investigate the prevalence of obesity among the 229 elementary school children(boys; 115 persons, girls; 114 persons) during 4 years by retrospective study. The results were as follows; 1. The mean height and weight of 229 subjects were 143.2cm(boys;143.4cm, girls; 142.7cm), 38.8kg(boys;40.4kg, girls;36.9kg), respectively. And other anthropometric body index such as the mean BMI, Rohrer Index, WLI and Obesity Index of subjects were 18.8(boys;19.5, girls; 18.0), 1.31(boys;1.36, girls; 1.26), 115.5(boys;121.4, girls; 108.9) and 110.6(boys;114.5, girls; 106.7), respectively. 2. The mean percentile values of height and weight of subjects were higher than the '85 Korean Children's Growth Standard, respectively. In the case of boys, the 75th percentile value of weights was larger than that's 97th's. And in the case of girls, the 75th percentile value of weights was equalled to the that's 90th's. 3. When the subjects were classified into 4 groups such as obese, overweight, normal, and lean groups according to Obesity Index, their percentages were 28.8%(boys; 38.3%, girls; 19.3%), ll.8%(boys; 9.6%, girls; 14.0%), 50.7%(boys; 47.0%, girls; 54.4%) and 8.7%(boys; 5.2%, girls; 12.3%), respectively. And only I person(3.3%) is classified into normal group and 2 persons(6.7%) are classified into overweight group when they become 5 grade among 30 persons(13.1%) who were classified into obese group when they were I grade. 4. Changes in percentage of subjects differentiated by 3 indices during 4 years(from I grade to 5 grade) were as follows; In the case of BMI were 5.2%, 5.2%, 11.8%, 21.0%, 27.5%. In the case of Roher index were 13.1%, 11.8%, 14.4%, 14.8%, 17.8%. And in the case of WLI were 15.7%, 21.6%, 29.5%, 32.2%, 36.7%. 5. There was no significant difference among 4 groups on the skip rate of breakfast(obese;48.5%, overweight;55. mean meal time of subjects took about 10 minutes which was short, and the eating rate of obese group was significantly shorter than that of other groups(p<0.05). There was a tendency that the rate of the obese or overweight group eating together in breakfast and dinner was lower than that of normal or lean group. The mean T.V. watching time and the rate of eating out of subjects were 1-2 hours/day and 1 or 2 times/week. In conclusion, the subjects have been grown remarkably compared to the '85 Korean Children's Growth Standard, especially boy's weight. In order to the elementary school children to be grew as healthful citizen they should recognize the importance of meals of everyday, the balanced meals, and desirable eating habits. In addition to these, we should educate the ways of meal-life to them. We also are in need to develope the methods of education for the students themselves and their parents so that could prevent the increase rate of obesity.

• Geomechanics and Engineering
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• v.7 no.5
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• pp.525-537
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• 2014

The typical design of ground improvement with prefabricated vertical drains (PVD) and surcharge preloading involves a series of deterministic analyses using averaged or mean soil properties for the various combination of the PVD spacing and surcharge preloading height that would meet the criteria for minimum consolidation time and required degree of consolidation. The optimum design combination is then selected in which the total cost of ground improvement is a minimum. Considering the variability and uncertainties of the soil consolidation parameters, as well as considering the effects of soil disturbance (smear zone) and drain resistance in the analysis, this study presents a stochastic cost optimization of ground improvement with PVD and surcharge preloading. Direct Monte Carlo (MC) simulation and importance sampling (IS) technique is used in the stochastic analysis by limiting the sampled random soil parameters within the range from a minimum to maximum value while considering their statistical distribution. The method has been verified in a case study of PVD improved ground with preloading, in which average results of the stochastic analysis showed a good agreement with field monitoring data.

• Korean Journal of Ecology and Environment
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• v.49 no.1
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• pp.31-41
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• 2016

Deutzia paniculata is an endemic species to the Korean Peninsula. Despite of importance for conservation, the population structure and habitat characteristics of D. paniculata have not been determined yet. We analyzed the ecological characteristics of the species based on the literature review and field survey. Field survey was conducted on May to October 2014 during which 11 quadrats of size $15{\times}15m$ were studied in six regions. Each of the quadrats were further divided into $5{\times}5m$ small quadrats and population characteristics were recorded. The population and habitat characteristics were analyzed, including species abundance (density and coverage), demographic attributes (flowering rates and fruiting plants), vegetation (structure, species composition), light availability (transmitted light and canopy openness) and soil characteristics (temperature and humidity). We found that D. paniculata mainly distributed in Gyeongsangdo (including Taebaek in Gangwondo) along a broad elevational range of 290~959 m (mean: 493 m) above sea level. In preferred habitat the species grows within the slope range of $7^{\circ}$ and $35^{\circ}$ with the average of $16^{\circ}$. D. paniculata was generally distributed on talus deposits and low adjacent slopes. The average number of individual plants per small quadrat was 12.5 with the mean density $0.5stems\;m^{-2}$. The vegetative reproduction was frequent in D. paniculata and mean flowering rate was as low as 15%. Altogether 138 taxa were found in whole observation area with the dominant tree species mainly spring ephemerals, such as Cornus controversa (importance value: 25.5%) and Fraxinus rhynchophylla (importance value: 15.8%). Although, C. controversa usually grows on steep slopes and F. rhynchophylla mostly distributed at high-altitudes, however, both species distributed in disturbed environments and among talus deposits. Thus based on our results, we concluded that D. paniculata is a disturbance-prone species, primarily existing in habitats subjected to natural disturbances, such as floods. The species occurs less at anthropogenically disturbed sites, thus there is no apparent threat to the populations and habitat of D. paniculata.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.2
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• pp.75-84
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• 2019

In this study, the random forest approach was used to predict the national mean rice yield of South Korea by using mean climatic factors at a national scale. A random forest model that used monthly climate variable and year as an important predictor in predicting crop yield. Annual yield change would be affected by technical improvement for crop management as well as climate. Year as prediction factor represent technical improvement. Thus, it is likely that the variables of importance identified for the random forest model could result in a large error in prediction of rice yield in practice. It was also found that elimination of the trend of yield data resulted in reasonable accuracy in prediction of yield using the random forest model. For example, yield prediction using the training set (data obtained from 1991 to 2005) had a relatively high degree of agreement statistics. Although the degree of agreement statistics for yield prediction for the test set (2006-2015) was not as good as those for the training set, the value of relative root mean square error (RRMSE) was less than 5%. In the variable importance plot, significant difference was noted in the importance of climate factors between the training and test sets. This difference could be attributed to the shifting of the transplanting date, which might have affected the growing season. This suggested that acceptable yield prediction could be achieved using random forest, when the data set included consistent planting or transplanting dates in the predicted area.