• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.17 no.4
• /
• pp.99-111
• /
• 2018

Service areas in expressways are very important facilities in terms of efficient expressway operation and the convenience of users. It needs a traffic management strategy to inform drivers in advance about congestion in service areas so as to distribute users of service areas. But due to the lack of sensors and data on numbers of people in the service areas, congestion in service areas had not been measured and managed appropriately. In this study, a congestion index for service areas was developed using telecommunication floating population big data. Two alternative indices (i.e., density of service areas and floating population V/c of service areas) were developed. Finally, the floating population V/c of service areas was selected as a congestion index for service areas for reasons of the ease of understanding and comparison.

• Journal of Korea Water Resources Association
• /
• v.51 no.11
• /
• pp.1011-1020
• /
• 2018

This study aims to develop a drought monitoring scheme based on groundwater which can be exploit for water supply under drought stress. In this context, groundwater level can be used as a proxy for better understanding the temporal evolution of drought state. First, kernel density estimator is presented in the monthly groundwater level over the entire national groundwater stations. The estimated cumulative distribution function is then utilized to map the monthly groundwater level into the standardized groundwater level index (SGI). The SGI for each station was eventually converted into the index for major cities through the Thiessen polygon approach. We provide a drought classification for a given SGI to better characterize the degree of drought condition. Ultimately, we conclude that the proposed monitoring framework enables a more reliable estimation of the drought stress, especially for a limited water supply area.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.28 no.1
• /
• pp.51-56
• /
• 2015

The object of this study is to obtain the optimum mix proportion of halogen free compound with flame resistance and, for the purpose, thermal/electrical characteristics test are conducted using compatibilizing agents, flame resistance agents, hydroxide aluminum, sunscreen, antioxidant and silicon oil on the base resin of linear low density polyethylene (LLDPE), Ethylene vinyl acetate copolymer (EVA). Existing compound method accompanies many requirements to be satisfied including a lot of addition of flame resistance agents, prohibition of impact on mixing capability with base and property and etc. In this study, different from the existing method, the optimum mix proportion is determined and experimented by adding nano clay. Oxygen index test shows no difference between specimens while T-6, T-9 shows oxygen index of 29[%] and 26[%], respectively. This is concluded that hydroxide aluminum, which is a flame resistance agent, leads low oxygen index. From UL94-V vertical flame resistance test, the combustion behavior is determined as V-0, Fail based on UL94-V decision criteria. Viscometry shows low measurements in specimens with separate addition of compatibilizing agents or nano clay. Volume resistivity test shows low measurement mainly in specimens without compatibilizing agents. Therefore, with the flame resistance compound shows better performance for thermal/electrical property and the optimum mix proportion are achieved among many existing materials.

• The Journal of the Korea Contents Association
• /
• v.20 no.1
• /
• pp.530-538
• /
• 2020

Recently, the suicide rate problem in Korea is very serious. Local governments are pushing various policies to lower suicide rates. The purpose of this study is to assess the difference in the suicide rate among regions and to identify the trend of change by concentration index(CI). The major findings are as follows. First, county suicide rate was the highest in the last 20 years and the lowest in the city. The low suicide rate in urban areas continues. Second, suicide rates are increasing in all regions. But the gap between the district and the county was decreasing. The difference in suicide rates between urban and rural areas is decreasing. Third, the suicide rate concentration index was negative for all 20 years. Suicide rates in low-density farming and fishing villages. Fourth, the absolute value of the concentration index has been continuously decreasing for 20 years. The gap between suicide and rural areas is decreasing. Therefore, inter-regional suicide rate is estimated to be leveling up.

• Journal of Bone Metabolism
• /
• v.25 no.4
• /
• pp.219-226
• /
• 2018

Background: Although studies and interest in sarcopenia have increased, it is still a matter of debate which muscle mass index better represents the aging process. We compared 3 indices for muscle mass (appendicular skeletal muscle mass [ASM]/weight, $ASM/height^2$, and the body mass index [BMI]-adjusted muscle mass index [ASM/BMI]) to determine which better reflected the aging process in terms of the decline in bone mineral density (BMD), visual acuity (VA), hearing power, renal function, pulmonary function, and handgrip strength. Methods: We performed a retrospective cross-sectional study using the Korea National Health and Nutrition Examination Survey in the Korean population. Between 2008 and 2011, a total of 14,415 men and 17,971 women aged 10 years or older participated in the study. We plotted the changes in the 3 indices of muscle mass and compared these with changes in BMD, VA, hearing power, renal function, pulmonary function, and handgrip strength according to each age group. Results: The ASM/BMI showed similar changes in terms of surrogate markers of the aging process, while the ASM/weight and $ASM/height^2$ showed no correlation. Conclusions: Among muscle indices for sarcopenia, only the ASM/BMI represented the aging process.

• Korean Journal of Clinical Laboratory Science
• /
• v.52 no.4
• /
• pp.364-371
• /
• 2020

The Korea Centers for Disease Control and Prevention is conducting surveillance of climate change vectors across all regions in Korea to counteract the spread of these vectors. As a part of this surveillance project, wild rodents were captured using traps to investigate the spread of chigger mites, the vector of Tsutsugamushi disease, across Jeonbuk, Jinan region, and to conduct studies on pathogens. Twenty samplers were used to sample chigger mites weekly from September to November in four different locations. Six hundred and eleven chigger mites of eight varying types were captured. The largest number of captured chigger mites was N. tamiyai, with 434 samples (71.0%). With the addition of 66 wild rodents captured from traps, 3,050 chigger mites were sampled, which yielded a Chigger index of 46.2. The monthly Chigger index was highest in November with a value of 206.1. the result of the test conducted in the presence of pathogens showed two positive results, each from May and September, out of all 85 pools. This result was aligned with the increased frequency in tsutsugamushi disease cases in spring and fall seasons.

• Geomechanics and Engineering
• /
• v.33 no.3
• /
• pp.279-289
• /
• 2023

Brittleness index (BI) is an important property of rocks because it is a good index to predict rockburst. Due to its importance, several empirical and soft computing (SC) models have been proposed in the literature based on the punch penetration test (PPT) results. These models are very important as there is no clear-cut experimental means for measuring BI asides the PPT which is very costly and time consuming to perform. This study used a novel Multivariate Adaptive regression spline (MARS), M5P, and white-box ANN to predict the BI of rocks using the available data in the literature for an improved BI prediction. The rock density, uniaxial compressive strength (σ_c) and tensile strength (σ_t) were used as the input parameters into the models while the BI was the targeted output. The models were implemented in the MATLAB software. The results of the proposed models were compared with those from existing multilinear regression, linear and nonlinear particle swarm optimization (PSO) and genetic algorithm (GA) based models using similar datasets. The coefficient of determination (R²), adjusted R² (Adj R²), root-mean squared error (RMSE) and mean absolute percentage error (MAPE) were the indices used for the comparison. The outcomes of the comparison revealed that the proposed ANN and MARS models performed better than the other models with R² and Adj R² values above 0.9 and least error values while the M5P gave similar performance to those of the existing models. Weight partitioning method was also used to examine the percentage contribution of model predictors to the predicted BI and tensile strength was found to have the highest influence on the predicted BI.

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• v.4 no.4
• /
• pp.159-176
• /
• 2023

The conservation of the raccoon dog (Nyctereutes procyonoides) in South Korea requires the protection and preservation of natural habitats while additionally ensuring coexistence with human activities. Applying habitat map modeling techniques provides information regarding the distributional patterns of raccoon dogs and assists in the development of future conservation strategies. The purpose of this study is to generate potential habitat distribution maps for the raccoon dog in South Korea using geospatial technology-based models. These models include the frequency ratio (FR) as a bivariate statistical approach, the group method of data handling (GMDH) as a machine learning algorithm, and convolutional neural network (CNN) and long short-term memory (LSTM) as deep learning algorithms. Moreover, the imperialist competitive algorithm (ICA) is used to fine-tune the hyperparameters of the machine learning and deep learning models. Moreover, there are 14 habitat characteristics used for developing the models: elevation, slope, valley depth, topographic wetness index, terrain roughness index, slope height, surface area, slope length and steepness factor (LS factor), normalized difference vegetation index, normalized difference water index, distance to drainage, distance to roads, drainage density, and morphometric features. The accuracy of prediction is evaluated using the area under the receiver operating characteristic curve. The results indicate comparable performances of all models. However, the CNN demonstrates superior capacity for prediction, achieving accuracies of 76.3% and 75.7% for the training and validation processes, respectively. The maps of potential habitat distribution are generated for five different levels of potentiality: very low, low, moderate, high, and very high.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.46 no.5
• /
• pp.82-92
• /
• 2018

The purpose of this study is to develop a model for the density management of planting sites and an additional model for new planting sites. In the Dongtan New Town of Hwaseong, there are buffer green spaces, with widths between 8m and 15m, between roads and apartment complexes. A total 38 survey plots were set to examine the planting patterns and the density of landscape trees. The Crown Overlapping Index (COI) was developed to assess the level of overcrowding as far as tree growth and development effectively. Pinus strobus recorded the most serious level of overcrowding growth and development. Its average density and average COI were very high at $0.3trees/m^2$ and 35.6%, respectively. There were many areas in which its COI was above 45%. The criteria for density management were set by standardizing the COI into three levels, which were above 45% (Type A), 30~45% (Type B), and under 30% (Type C). A model was proposed to manage poorly growing trees and to develop a model to select and manage trees of similar specification based on the planting patterns. The trees of density management areas were reviewed in terms of tree types and the ease of transplanting to establish an application system for the management plans according to the possibility of transplanting, thinning, and pruning. In new buffer green spaces, the planting density of Pinus strobus was lowered to $0.20{\sim}0.25trees/m^2$, with that of shrubs being reduced to $1.5{\sim}2.0trees/m^2$, leading to a planting design model to cover the lower parts in at least 30~40%.

• Journal of Yeungnam Medical Science
• /
• v.20 no.1
• /
• pp.53-61
• /
• 2003

Background: Body weight is an important factor that influence the bone density in postmenopausal women except estrogen dificiency. However, different results are reported about the relationship between body composition and bone density in the postmenopausal women. We have studied the relationship between age, body weight, body mass index (BMI), waist hip ratio (WHR), muscle mass, fat mass, fat free mass and bone density. Materials and Methods: We have studied 127 persons of postmenopausal women who visited university medical center and examined the inbody 3.0 and Dual Energy X-ray Absorptiometry (DEXA) from Jan, 2001 to Jun, 2002. they didn't have any disease and didn't received hormone therapy, osteoporosis therapy or other medication that influence the bone density. Results: The numbers of study subjects is total 127 persons. Mean age is $56.9{\pm}5.14$, mean weight is $59.3{\pm}8.7kg$, mean BMI is $25.37{\pm}3.16(kg/m^2)$, mean fat mass is $20.02{\pm}5.05kg$, mean muscle mass is $37.49{\pm}4.50kg$, mean fat free mass is $39.80{\pm}4.70$, mean BMD is $0.828{\pm}0.148(g/cm^2$). In the result of linear regression analysis, age, height, weight, muscle mass, fat free mass, fat mass, BMI are significant determinants of BMD. In stepwise multiple regression analysis, age is the most significant determinant of BMD and besides age, fat free mass is the most significant determinant of BMD among body composition. Conclusion: In postmenopausal women, age, height, weight, BMI, muscle mass, fat free mass, fat mass are significant determinants of BMD and besides age, fat free mass is the most significant determinant of BMD among the body composition. So, diet and exercise that increase fat free mass will contribute to bone density increment.