• Journal of the Korea Convergence Society
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• v.10 no.9
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• pp.91-98
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• 2019

The research focused on plastic surgery clinics in Seoul, which recently responded to foreign patients who wanted to get plastic surgery, to recognize the need for the use of mobile healthcare applications to promote medical tourism and to see the expected effects in the future. For the analysis of data, SPSS 21.0 was used. Based on personal characteristics and medical institution characteristics, the future expected effects of using mobile healthcare applications were analyzed to find ways to help vitalize medical tourism. The result showed that the more mobile applications they wants to use in the future and the higher the number of foreign patients of the medical institutions, the more positive the expectation on the use of mobile healthcare application in the future. Also, the higher evaluation on the need for mobile healthcare application, the more helpful in vitalizing the medical tourism in the future, and the higher the positive awareness. I hope that this research will provide an IT foundation for the and expansion of mobile service app on demand analysis and service utilization of medical workers in order to promote medical tourism.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.3
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• pp.347-362
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• 2019

Underground excavation using TBM machines has been increasing to reduce complaints caused by noise, vibration, and traffic congestion resulted from the urban underground construction in Korea. However, TBM excavation design and construction still need improvement because those are based on standards of the technologically advanced countries (e.g., Japan, Germany) that do not consider geological environment in Korea at all. Above all, although TBM performance is a main factor determining the TBM machine type, duration and cost of the construction, it is estimated by only using UCS (uniaxial compressive strength) as the ground parameters and it often does not match the actual field conditions. This study was carried out as part of efforts to predict penetration rate suitable for Korean ground conditions. The effective parameters were defined through the correlation analysis between the penetration rate and the geotechnical parameters or TBM performance parameters. The effective parameters were then used as variables of the multiple regression analysis to derive a regression model for predicting TBM penetration rate. As a result, the regression model was estimated by UCS and joint spacing and showed a good agreement with field penetration rate measured during TBM excavation. However, when this model was applied to another site in Korea, the prediction accuracy was slightly reduced. Therefore, in order to overcome the limitation of the regression model, further studies are required to obtain a generalized prediction model which is not restricted by the field conditions.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.137-153
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• 2019

Estimating tunnel construction time and costs are the most fundamental part of a tunnel project planning, which has been generally assessed on a deterministic basis until now. In this paper, excavation cycle time was investigated for two road tunnels and one subway tunnel, and the results were compared with the Standard of Construction Estimate (SE), which is made for the estimation of construction time and cost in a design stage. The results show that the difference in cycle time between SE and actual cycle time is 50%, 7% and 31% respectively for the three tunnels, which means that SE does not reflect practical operation time. The major reasons of the difference are skilled level of tunneling workers, the change of operation sequences for more effective operations, much more complicated working atmosphere in a tunnel than the assumption of SE etc. Finally, even though the results can not be generalized since investigated tunnels are only 3, but it is thought that SE needs to be upgraded into the model able to consider quite common situations through additional tunnel investigation and studies in the future.

• The Korean Journal of Applied Statistics
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• v.32 no.1
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• pp.111-128
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• 2019

Subways are eco-friendly public transportation that can transport large numbers of passengers safely and quickly. It is necessary to predict the accurate number of passengers in order to increase public interest in subway. This study groups stations on Lines 1 to 9 of the Seoul Metropolitan Subway using clustering analysis. We propose one final prediction model for all stations and three optimal prediction models for each cluster. We found three groups of stations out of 294 total subway stations. The Group 1 area is industrial and commercial, the Group 2 ares is residential and commercial, and the Group 3 area is residential districts. Various data mining techniques were conducted for each group, as well as driving some influential factors on demand prediction. We use our model to predict the number of passengers for 8 new stations which are part of the 3rd extension plan of Seoul metro line 9 opened in October 2018. The estimated average number of passengers per hour is from 241 to 452 and the estimated maximum number of passengers per hour is from 969 to 1515. We believe our analysis can help improve the efficiency of public transportation policy.

• The Journal of Engineering Geology
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• v.28 no.4
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• pp.673-686
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• 2018

The physical properties of rocks constituting the rock mass were analyzed by using various methods such as 7 kinds of physical properties of about 2,400 data. The correlation equation was derived from the correlation equation with the dependent variables by screening independent variables through the significance level using multiple regression analysis. In order to verify the reliability of this equation, verification was performed through comparison with actual data using artificial neural network learning. The analysis results by petrogenesis and strength confirmed that the elastic wave velocity (compressional wave) and elastic modulus as the main influence factors for the independent variables affecting the dependent variables. This proves that most of the correlation equations using the above items are found in existing studies. And through this study, it is confirmed whether the rock classification is based on the above items in various standards. In addition, the analysis results of representative rocks showed a high correlation as the equation for estimating unconfined compressive strength and elastic modulus exceeds the coefficient of determination 0.8.

• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.2895-2905
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• 2018

We present a mixed multiplicative quantitative randomized response model which added a unrelated quantitative attribute and forced answer to the multiplicative model suggested by Bar-Lev et al. (2004). We also try to set up theoretical grounds for estimating sensitive quantitative attribute according to circumstances whether or not the information for unrelated quantitative attribute is known. We also extend it into the stratified mixed multiplicative quantitative randomized response model for stratified population along with two allocation methods, proportional and optimum allocation. We can see that the various quantitative randomized response models such as Eichhorn-Hayre's model (1983), Bar-Lev et al.'s model (2004), Gjestvang-Singh's model (2007) and Lee's model (2016a), are one of the special occasions of the suggested model. Finally, We compare the efficiency of our suggested model with Bar-Lev et al.'s (2004) and see that the bigger the value of $C_z$, the more the efficiency of the suggested model is obtained.

• Clean Technology
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• v.27 no.3
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• pp.261-268
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• 2021

Equilibrium, kinetics, and thermodynamics of adsorption of acid black 1 (AB1) by coal-based granular activated carbon (CGAC) were investigated with the adsorption variables of initial concentration of dye, contact time, temperature, and pH. The adsorption reaction of AB1 by activated carbon was caused by electrostatic attraction between the surface (H⁺) of activated carbon and the sulfite ions (SO₃^-) and nitrite ions (NO₂^-) possessed by AB1, and the degree of reaction was highest at pH 3 (97.7%). The isothermal data of AB1 were best fitted with Freundlich isotherm model. From the calculated separation factor (1/n) of Freundlich, it was confirmed that adsorption of AB1 by activated carbon could be very effective. The heat of adsorption in the Temkin model suggested a physical adsorption process (< 20 J mol^-1). The kinetic experiment favored the pseudo second order model, and the equilibrium adsorption amount estimated from the model agreed to that given by the experiments (error < 9.73% ). Intraparticle diffusion was a rate controlling step in this adsorption process. From the activation energy and enthalpy change, it was confirmed that the adsorption reaction is an endothermic reaction proceeding with physical adsorption. The entropy change was positive because of an active reaction at the solid-liquid interface during adsorption of AB1 on the activated carbon surface. The free energy change indicated that the spontaneity of the adsorption reaction increased as the temperature increased.

• Korean Journal of Clinical Laboratory Science
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• v.53 no.3
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• pp.249-256
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• 2021

Asthma is a chronic inflammatory airway disease. There are many factors including genetic and environmental factors that influence asthma. The mitogen-activated protein kinase (MAPK) pathway is involved in maintaining the T helper cells 1 and 2 (Th1/Th2) balance and plays an important role in the development of asthma. In this study, the correlation between the NDFIP2 gene that regulates the MAPK pathway and asthma was analyzed. The genetic polymorphism of the NDFIP2 gene was analyzed between 193 asthma patients and 3,228 healthy controls in Korea. As a result, 4 single nucleotide polymorphisms (SNPs) showed a significant correlation (P<0.05) and high relative risk with asthma. Among them, rs2783122 of NDFIP2 showed a statistically significant association with asthma (P-value=9.76×10^-6, odds ratio (OR)=1.67, 95% confidence interval (CI)=1.33~2.10). In the SNP imputation on the NDFIP2, 16 SNPs were discovered, and all of them showed significant correlation with asthma and high odds ratio. The genotype-based mRNA expression analysis revealed that the group of minor alleles of rs1408049 showed increased mRNA expression. Increased NDFIP2 expression causes the activation of the MAPK pathway, and this may influence the development of asthma. In conclusion, the polymorphisms of NDFIP2 are associated with asthma development and this can provide the basis for new guidelines for the management of asthma in the Korean population.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.521-531
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• 2020

QZSS (Quasi-Zenith Satellite System) provides the CLAS (Centimeter Level Augmentation Service) through the satellite's L6 band. CLAS provides correction messages called C-SSR (Compact - State Space Representation) for GPS (Global Positioning System), Galileo and QZSS. In this study, CLAS messages were received by using the AsteRx4 of Septentrio which is a GPS receiver capable of receiving L6 bands, and the messages were decoded to acquire C-SSR. In addition, Multi-GNSS (Global Navigation Satellite System) Code-PPP (Precise Point Positioning) was developed to compensate for GNSS errors by using C-SSR to pseudo-range measurements of GPS, Galileo and QZSS. And non-linear least squares estimation was used to estimate the three-dimensional position of the receiver and the receiver time errors of the GNSS constellations. To evaluate the accuracy of the algorithms developed, static positioning was performed on TSK2 (Tsukuba), one of the IGS (International GNSS Service) sites, and kinematic positioning was performed while driving around the Ina River in Kawanishi. As a result, for the static positioning, the mean RMSE (Root Mean Square Error) for all data sets was 0.35 m in the horizontal direction ad 0.57 m in the vertical direction. And for the kinematic positioning, the accuracy was approximately 0.82 m in horizontal direction and 3.56 m in vertical direction compared o the RTK-FIX values of VRS.

• Korean Journal of Psychosomatic Medicine
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• v.28 no.2
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• pp.135-142
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• 2020

Objectives : To identify the relationship between somatization, stress, depression, anxiety, and psychological symptoms risk for nurses working in the intensive care unit. Create clinical evidence of psychosomatic medicine research and complement the meaning of somatization. Methods : Seventy of the mental health checkups conducted by the National Mental Health Center among the nurses using tools including Perceived Stress scale, Fatigue Severity Scale, Patient Health questionnaire-15, Korean Beck Depression Inventory, Korean Beck Anxiety Inventory, and Symptom Checklist-90-Revision. Results : 12.9% of the patients experienced more than moderate somatization. There was no statistical relationship between somatization and psychological stress perception, but feeling of anxiety and decreased self-confidence were related to the level of somatization. The group with severe somatization experienced more depression and anxiety. The group with high physical fatigue also had no statistical relationship with psychological stress perception, but had an effect on the feeling of tension, stress, or decreased control. Physical fatigue level was increased by experience of depression, not by anxiety. For psychological symptoms the higher the level of somatization, the higher the obsession and hostility was explored. In the linear regression model, stress, depression, and anxiety accounted for 39.3% of somatization and 16.1% of physical fatigue symptoms. Conclusions : We can estimate the decrease in stress cognitive symptoms, accompanying depression and anxiety, compulsion and hostility as characteristics of somatization. The causal relationship between somatization and psychological symptoms cannot be confirmed in this study, but the interrelationships are observed, can be referred to mediation strategies.