• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.1
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• pp.63-73
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• 2024

Autonomous vehicles at Levels 3 to 5, currently under global research and development, seek to replace the driver's perception, judgment, and control processes with various sensors integrated into the vehicle. This integration enables artificial intelligence to autonomously perform the majority of driving tasks. However, autonomous vehicles currently obtain temporary driving permits, allowing them to operate on roads if they meet minimum criteria for autonomous judgment abilities set by individual countries. When autonomous vehicles become more widespread in the future, it is anticipated that buyers may not have high confidence in the ability of these vehicles to avoid hazardous situations due to the limitations of temporary driving permits. In this study, we propose a method for grading the judgment abilities of autonomous vehicles based on a driving simulator experiment comparing and evaluating drivers' abilities to avoid hazardous situations. The goal is to derive evaluation criteria that allow for grading based on specific scenarios and to propose a framework for grading autonomous vehicles. Thirty adults (25 males and 5 females) participated in the driving simulator experiment. The analysis of the experimental results involved K-means cluster analysis and independent sample t-tests, confirming the possibility of classifying the judgment abilities of autonomous vehicles and the statistical significance of such classifications. Enhancing confidence in the risk-avoidance capabilities of autonomous vehicles in future hazardous situations could be a significant contribution of this research.

• Journal of the Korean Applied Science and Technology
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• v.40 no.6
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• pp.1298-1308
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• 2023

This study collected 245 questionnaires from college students in Gyeonggi-do and analyzed them using SPSS statistical packages, with the aim of identifying the status of hair loss perception due to the relationship between stress and hair loss received by college students and analyzing the correlation between stress and hair loss perception by type. As a result of the study, it was analyzed that the biggest problem caused by hair loss was 'loss of confidence', and in particular, people who were stressed about career/employment and studies were analyzed to consider the problem of 'loss of confidence' the most serious. As a result of cross-analysis of the general characteristics of awareness and the 'most recent stress' item, and as a result of correlation analysis between stress by type and hair loss status that constitutes hair loss awareness, it was analyzed that all types of stress affect hair loss in college students. Among them, career/employment stress and academic stress were found to be the most influential stress, and in the event of hair loss, it was analyzed that they were more willing to engage in hair loss treatment for career/employment, study, and appearance before interpersonal relationships or economic problems. Therefore, this study is of great significance in that it classified stress by type and analyzed the correlation through empirical research methods by specifying the contents of hair loss recognition into three categories: hair loss status, hair loss management, and hair loss treatment.

• Journal of the Korean Geotechnical Society
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• v.40 no.5
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• pp.93-101
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• 2024

Numerical analysis methods are widely used to assess the safety of hydrogen storage facilities; however, obtaining data under various conditions poses significant challenges. This study aims to expand the dataset using oversampling algorithms and utilize these enhanced datasets as diverse input parameters for numerical analysis. The oversampling techniques applied include SMOTE, Borderline-SMOTE, ADASYN, and CTGAN, with data amplified by factors of 2, 5, and 100 relative to the original dataset. This approach increases data volume based on the characteristics of the existing data, which may consequently introduce outliers. To address this, statistical methods such as the 3-sigma rule and the confidence level method are employed to identify and remove outliers beyond the normal distribution range. The reliability of the conditions generated through data amplification and outlier analysis is evaluated by comparing them with trends observed in the original dataset. Additionally, the SHAP algorithm is utilized to analyze changes in the importance values of each parameter. The SHAP values derived from the original dataset and those processed through AI techniques and outlier analysis exhibit similar trends, validating the proposed methodologies. The methods proposed in this paper are applicable not only to hydrogen storage facilities but also to the systematic construction of data for assessing the stability of various geotechnical structures.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.21 no.3
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• pp.140-149
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• 2008

Objective : This study was performed to find out the difference of symptoms between rhinitis and sinusitis in young patients who were diagnosed by PNS plain radiograph( PNS series), Methods: We did statistical analysis about 147 new outpatients under 12 year-old who had visited the department of ophthalmology, otolaryngology, dermatology in Kyung Hee Oriental Medicine Center from March 2, 2006 to February 29, 2008. All of the patients were diagnosed by PNS series and we divided the patients with two groups; rhinitis group and sinusitis group. We checked the OPD records and explore the distribution on sex, experience of past western therapy, age and duration. Then we divided symptoms into nine; 'nasal obstruction', 'purulent rhinorrhea', 'cough & sneezing', 'watery rhinorrhea', postnasal drip', 'sputum', 'head problem', 'snoring & throat discomfort' and 'epistaxis'. We also divided age into 2 groups: $0\sim7$ years old and $8{\sim}12$ years old. We carried out chi-square test as a statistical method. Results : The results were as follows. 1. Sinusitis group were 102(69.5%); 62 have only sinusitis. 40 have both sinusitis and adenoidal hypertrophy. Rhinitis group were 45(30.5%); 13 have adenoidal hypertrophy and 32 were negative. 2. Male were 98(sinusitis 65, rhinitis 33), female were 49(sinusitis 37, rhinitis 12). 3. Patients who had experienced past western therapy were 120(sinusitis 81, rhinitis 39), no experienced patients were 27(sinusitis 21, rhinitis 6). 4. Distribution on age of sinusitis was 1(1 yr), 2(2 yrs), 3(3 yrs), 15(4 yrs), 15(5 yrs), 23(6 yrs), 13(7 yrs), 12(8 yrs), 8(9 yrs), 5(10 yrs), 1(11 yrs), 4(12 yrs). Distribution on age of rhinitis was 1(1 yr), 0(2 yrs), 1(3 yrs), 1(4 yrs), 9(5 yrs), 5(6 yrs), 3(7 yrs), 5(8 yrs), 1(9 yrs), 8(10 yrs), 6(11 yrs), 5(12 yrs), 5. Duration of sinusitis was 20(<2 months), 6($2{\sim}3$ months), 11($3\sim6$ months), 34($6\sim12$ months), 31(>12 months) and of Rhinitis was 11(<2 months), 0($2\sim3$ months), 5($3\sim6$ months), 18($6\sim12$ months), 11(>12 months) 6. Distribution on symptoms, sinusitis patients were 86(nasal obstruction), 52(purulent rhinorrhea), 46(cough & sneezing), 38(watery rhinorrhea), 41(postnasal drip), 23(sputum), 18(head problem), 15(snoring & throat discomfort), 6(epistaxis). The each symptom and sinusitis have no relation by chi-square test. 7. The number of patients who were 0 $\sim$ 7 years old was 92: sinusitis 72(49%), non-sinusitis 20(13.6%). The number of patients who were 8 $\sim$ 12 years old was 58: sinusitis 30(20.4%), non-sinusitis 25(l7%). By chi-square test(confidence level 95%), sinusitis and age under 7 have a significant relation(p=0.003). Conclusions : There is no relation between rhinologic symptoms and sinusitis. Patients under 7 years old with rhinologic symptoms tend to have sinusitis.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.149-159
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• 1998

The reasonable prediction of time-dependent deformation of prestressed concrete(PSC) box girder bridges is very important for accurate construction as well as good serviceability. The long-term behavior is mostly influenced by the probabilistic characteristic of creep and shrinkage. This paper presents a method of statistical analysis and sensitivity analysis of creep and shrinkage effects in PSC box been taken into account - model uncertainty, parameter variation and environmental condition. The statistical and sensitivity analyses are performed by using the numerical simulation of Latin Hypercube sampling. For each sample, the time-dependent structural analysis is performed to produce response data, which are then statistically analyzed. The probabilistic prediction of the confidence limits on long-term effects of creep and shrinkage is then expressed. Three measure are examined to quantify the sensitivity of the outputs of each of the input variables. These are rank correlation coefficient(RCC), partical rank correlation coefficient(PRCC) and standardiozed rank regression coefficient(SRRC) computed on the ranks of the observations. Three creep and shrinkage models - i. e., ACI model. CEB-FIP model and the model in Korea Highway Bridge Specification - are studied. The creep model uncertainy factor and the relative humidity appear to be the most dominant factors with regard to the model output uncertainty.

• Journal of Pharmaceutical Investigation
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• v.38 no.5
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• pp.335-342
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• 2008

The bioequivalence of two carbamazepine preparations was conducted. The in vivo bioequivalence study in 20 healthy male Korean volunteers was designed by using a single dose, randomized, 2-period crossover with a 3-weeks washout period between the doses. Prior to the in vivo study, an in vitro comparative dissolution test was performed by the paddle and basket method as described in the bioequivalence guidance of the Korea Food and Drug Administration (KFDA). Based on the similar dissolution pattern between two preparations in the dissolution test, the two formulations are demonstrated to be pharmaceutically equivalent. In addition, in vivo bioequivalence test was used to reconfirm the in vitro dissolution results. In the in vivo bioequivalence study, the plasma concentrations of carbamazepine up to 144 h after the administration were determined using a validated HPLC method with UV detection and the bioequivalence between the two drug products was assessed by statistical analysis of the log transformed mean ratios of $C_{max}$, $AUC_{0-t}$ and $AUC_{0-\infty}$. The mean maximum concentration ($C_{max}$) of the test and reference were found to be $1467.0{\pm}335.8\;ng/mL$ and $1465.9{\pm}310.3\;ng/mL$, respectively. The 90% confidence intervals (C.I.) of $C_{max}$ were in the range from 0.95 to 1.05. As for the $AUC_{0-t}$ and $AUC_{0-\infty}$, test values were $110027.1{\pm}27786.4\;ng/mL{\cdpt}h$, $128807.0{\pm}34563.2\;ng/mL{\cdot}h$ and $105473.6{\pm}26496.2\;ng/mL{\cdot}h$, $125448.5{\pm}35975.5\;ng/mL{\cdot}h$, respectively. The 90% C.I. of $AUC_{0-t}$ were 0.97 to 1.10 and of $AUC_{0-\infty}$, 0.99 to 1.09 and thus were within the log 0.8-log 1.25 interval proposed by the KFDA. A two-way ANOVA showed no significant difference between the two formulations. Based on these statistical analysis, it was concluded that the test formulation is bioequivalent to the reference.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.102-115
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• 2017

This study, focused on customers of tourist industry events, aims to examine the influence of service quality on customer satisfaction and customer loyalty. The overall explanatory power ($R^2$) on the dependent variable 'customer satisfaction' in relation to service quality was found to be 47.1%, and the overall explanatory power($R^2$) on the dependent variable 'customer loyalty' in relation to service quality was 36.6%. The F-test, which was conducted to determine the statistical significance of the above regression equation, showed a value of 157.599, thus confirming the statistical significance of the regression equation on how service quality affects customer loyalty. The t-test, was conducted to determine the statistically significant variables of service quality of tourism industry events (t=5.359, p= .000). Furthermore, the analysis showed that customer satisfaction had a positive (+) influence on customer loyalty (t=12.554, p= .000). Therefore the hypothesis that the quality of service affects customer satisfaction and loyalty was supported. As a result, it was found that the higher the level of service quality, tangibility, reliability, responsiveness, confidence empathy, and event quality, the higher the customer satisfaction level.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.1
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• pp.12-20
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• 2009

Statement of problem: When an implant is fixed, a fixture comes into contact with a tissue fluid. Adhesion of a tissue fluid to a surface of implant is various case by case. Purpose: The ultimate goal of this work is to analyze a correlation between a surface roughness and wettability of implant specimens. A measurement for wettability is performed considering 4 types of specimen implant with surface treatments different from each other to investigate the change of wettability with the elapse of time. Material and methods: Firstly, 20 specimens of titanium were prepared. The specimen were made of a commercial Titanium Grade IV with the diameter of 10 mm and the thickness of 1 mm. According to the method of surface treatment, the specimens were classified into 4 groups of 5 specimens per group. Group A: Machined Surface Group B: Anodized surface Group C: RBM (HA blasting) surface Group D: CMP (calcium methaphosphate) coating surface. Surface roughness of specimen was measured using SV-3000S4 (Mituyoto, Japan). The measurement was based on the standard of JIS1994. Sessile drop method was used to measure the wettability, which measures contact angle between implant disc and saline with the time interval of 5, 10, and 15 seconds. SPSS 11.0 was used to analyze the collected data. In order to analyze the difference of wettability and surface roughness according to implant surface treatment method. The statistical significance was tested with the confidence level of 95%. Pearson's correlation coefficient was used to evaluate the correlation of surface roughness and wettability. Results: The difference of surface roughness was statistically significant in the order of Group C ($1.69{\pm}0.26$), Group D ($1.58{\pm}0.16$), Group B ($0.78{\pm}0.14$) Group A ($0.18{\pm}0.05$). The wettability has also a statistically significant difference, which was in the order of group B ($17.70{\pm}2.66$), Group C ($27.86{\pm}4.52$), Group D ($66.28{\pm}3.70$) Group A ($70.52{\pm}8.00$). There was no difference in wettability with the passage of time. Conclusions: 1. The surface roughness was high in the order of RBM, CMP, Anodized, Machined group (P<.05). 2. The wettability was high in the order of Anodized, RBM, CMP, Machined group (P<.05). 3. There was no statistical significance in the correlation of surface roughness and wettability.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5325-5329
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• 2013

Objectives: Although there are many reports about the risk of breast cancer, few have reported clinical factors including history of breast-related or other diseases that affect the prevalence of breast cancer. This study explores these risk factors for breast cancer cases reported in Beijing in 2009. Materials and Methods: Data were derived from a Beijing breast cancer screening performed in 2009, of 568,000 women, from 16 districts of Beijing, all aged between 40 and 60 years. In this study, multilevel statistical modeling was used to identify clinical factors that affect the prevalence of breast cancer and to provide more reliable evidence for clinical diagnostics by using screening data. Results and Conclusion: Those women who had organ transplants, compared with those with none, were associated with breast cancer with an odds ratio (OR)=65.352 [95% confidence interval (CI): 8.488-503.165] and those with solid breast mass compared with none had OR=1.384 (95% CI: 1.022-1.873). Malignant tendency was strongly associated with increased risk of breast cancer, OR=207.999(95% CI: 151.950-284.721). The risk of breast cancer increased with age, $OR_1$=2.759 (95% CI: 1.837-4.144, 56-60 vs. 40-45), $OR_2$=2.047 (95% CI: 1.394-3.077, 51-55 vs. 40-45), $OR_3$=1.668 (95% CI: 1.145-2.431). Normal results of B ultrasonic examination show a lower risk among participants, OR= 0.136 (95% CI: 0.085-0.218). Those women with ductal papilloma compared with none were associated with breast cancer, OR=6.524 (95% CI: 1.871-22.746). Therefore, this study suggests that clinical doctors should pay attention to these high-risk factors.

• Journal of Korean society of Dental Hygiene
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• v.17 no.3
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• pp.369-380
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• 2017

Objectives: The purpose of this study is to investigate the effect of preventive treatment experience on scaling fear level. Methods: A total of 259 adults who had visited the dental clinic were analyzed. The results were summarized as follows. Statistical analysis of the collected data was performed using the SPSS WIN 20.0 statistical program. The general characteristics, scaling experience, and the characteristics of the subjects were analyzed. Frequency of scaling according to general characteristics was analyzed by independent sample t-test, Scaling fears according to treatment experience were tested by t-test. Correlation analysis was performed for scaling fears according to the reliability of dental hygienist. Regression analysis was carried out to investigate factors affecting scaling fear. Results: Level of fear during scaling was higher in females (3.03) than in males (2.54) and that after scaling was scored higher in females (2.68) than in males (2.34) by general characteristics (p<0.001). The adults who were not healthy in oral health showed the highest levels of fear during (3.29) and after (3.00) scaling by oral health status (p<0.001). Adults who had brushing education experience showed lower fear level than those who did not after scaling (p<0.01) according to the experiences of preventive treatments. With respect to the correlation of trust level to the dental hygienists with the scaling fears, it showed higher in the trust level (-0.688) as lower level of scaling fear (-0.642) in the scaling (p<0.01). Confidence level of dental hygienist (-0.661), brushing education experience (-0.121), and oral health status (-0.121) were influenced upon the regression analysis. Conclusions: Oral health education and dental hygiene education are increasing. It is thought that active efforts are needed to promote and maintain oral health.