• Communications for Statistical Applications and Methods
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• 제29권1호
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• pp.65-83
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• 2022

Although various statistical methods have been developed to map time-dependent genetic factors, most identified genetic variants can explain only a small portion of the estimated genetic variation in longitudinal traits. Gene-gene and gene-time/environment interactions are known to be important putative sources of the missing heritability. However, mapping epistatic gene-gene interactions is extremely difficult due to the very large parameter spaces for models containing such interactions. In this paper, we develop a Gaussian process (GP) based nonparametric Bayesian variable selection method for longitudinal data. It maps multiple genetic markers without restricting to pairwise interactions. Rather than modeling each main and interaction term explicitly, the GP model measures the importance of each marker, regardless of whether it is mostly due to a main effect or some interaction effect(s), via an unspecified function. To improve the flexibility of the GP model, we propose a novel grid-based method for the within-subject dependence structure. The proposed method can accurately approximate complex covariance structures. The dimension of the covariance matrix depends only on the number of fixed grid points although each subject may have different numbers of measurements at different time points. The deviance information criterion (DIC) and the Bayesian predictive information criterion (BPIC) are proposed for selecting an optimal number of grid points. To efficiently draw posterior samples, we combine a hybrid Monte Carlo method with a partially collapsed Gibbs (PCG) sampler. We apply the proposed GP model to a mouse dataset on age-related body weight.

• 농촌계획
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• 제26권4호
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• pp.1-13
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• 2020

This study was aimed at improving the landscape agricultural facilities. Agricultural production spaces such as rice paddies and fields are a representative landscape of rural areas. These landscapes should be aesthetically presentable and as such, they require proper landscape planning and management. However, the construction of infrastructure in these landscapes presents environmental and ecological problems. As a result, the unique aesthetics in landscapes such as rice paddies is disrupted by infrastructure development. The construction of infrastructural complexes takes away the pleasantness of the natural landscape. Photographic slides were variable elements were systematically removed in the landscape were used. The original plan and its alternatives (1, 2, 3, 4) in the BV, JV, JG, and GG regions were evaluated using the Likert scale and AHP methods. Statistical analysis was conducted using ANOVA. The results indicate that the removal of variable elements, expansion of separation distance, and the planting of green plants had a positive effect on all parameters. Improvement of landscapes containing infrastructural complexes can be achieved by the use of image simulation.

• 한국전자거래학회지
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• 제24권3호
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• pp.53-71
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• 2019

소프트웨어 시스템이 복잡하고 대규모화 되어감에 따라 새로운 기능을 제공하기 위해 소프트웨어 컴포넌트 또는 모듈을 재사용하는 방법을 요구하고 있다. 본 논문에서는 서비스 제공자와 서비스 사용자에게 SOA와 MSPL을 결합하여 가변성 서비스를 제공하고 재사용하여 웹 시스템 개발 방법을 제시하였다. 제시한 방법은 서비스 제공자 관점에서, 재사용 가능한 가변성 서비스를 휘처 식별 가이드라인을 적용하여 신택스 기반, 기능기반과 행위기반 방법으로 휘처로 식별하고 구현하여 재사용 자산으로 관리하였다. 그리고 사용자 관점에서 서비스를 구조적으로 조합하고 재구성하는 방법으로서 워크플로우를 모델링하여 서비스를 구성하여 웹 시스템을 구현하였다. 본 논문에서 구축한 웹 시스템의 재사용을 기능점수로 측정한 결과 재사용의 증가와 유사프로젝트에 적용해 비용 절감 효과를 검증하였다.

• Journal of Korean Neurosurgical Society
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• 제64권1호
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• pp.13-22
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• 2021

Objective : High precision and accuracy are expected in gamma knife radiosurgery treatment. Because of the requirement of clinically applying complex radiation and dose gradients together with a rapid radiation decline, a dedicated quality assurance program is required to maintain the radiation dosimetry and geometric accuracy and to reduce all associated risk factors. This study investigates the validity of Leksell Gamma plan (LGP)10.1.1 system of 5th generation Gamma Knife Perfexion as modified variable ellipsoid modeling technique (VEMT) method. Methods : To verify LGP10.1.1 system, we compare the treatment plan program system of the Gamma Knife Perfexion, that is, the LGP, with the calculated value of the proposed modified VEMT program. To verify a modified VEMT method, we compare the distributions of the dose of Gamma Knife Perfexion measured by Gafchromic EBT3 and EBT-XD films. For verification, the center of an 80 mm radius solid water phantom is placed in the center of all sectors positioned at 16 mm, 4 mm and 8 mm; that is, the dose distribution is similar to the method used in the x, y, and z directions by the VEMT. The dose distribution in the axial direction is compared and analyzed based on Full-Width-of-Half-Maximum (FWHM) evaluation. Results : The dose profile distribution was evaluated by FWHM, and it showed an average difference of 0.104 mm for the LGP value and 0.130 mm for the EBT-XD film. Conclusion : The modified VEMT yielded consistent results in the two processes. The use of the modified VEMT as a verification tool can enable the system to stably test and operate the Gamma Knife Perfexion treatment planning system.

• 보건행정학회지
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• 제33권4호
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• pp.389-399
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• 2023

Background: The purpose of this study is to analyze the factors affecting the unmet healthcare needs of older people with chronic diseases in Korea and provide a basic research report to strengthen their access to medical care. Methods: In the 2020 older people survey data, 8,182 older people aged 65 or older who were diagnosed with one or more chronic diseases were the final subjects of the study. According to Andersen's behavioral model used in unmet healthcare needs, independent variables were composed of predisposing factors, possible factors, and necessary factors, and whether or not unmet healthcare needs was set as dependent variable. Results: Of the older people with chronic diseases, 1.6% experienced unmet healthcare needs, of which 55.9% experienced unmet healthcare needs for reasons related to economic burden, 31.6% physical constraints, and 12.5% time constraints. As a result of the analysis, older people with chronic diseases were more likely to experience unmet healthcare needs if they were relatively low in age, low in education level, no spouse, low in household income, poor subjective health, complex chronic diseases, and functional restrictions. However, by major reasons for experiencing unmet healthcare needs, living in rural areas were more likely to experience unmet healthcare needs due to physical constraints, and those who participated in economic activities and who had were more likely to experience unmet healthcare needs due to time burden. These results were not derived when only unmet healthcare needs was set as the dependent variable. Conclusion: This study emphasizes the need for an approach by cause of unmet medical occurrence by suggesting that there are differences in influencing factors by reason for experiencing unmet healthcare needs.

• 대한간호학회지
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• 제54권2호
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• pp.193-210
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• 2024

Purpose: The objective of this study was to develop a predictive model for the sexual experiences of adolescents using the random forest method and to identify the "variable importance." Methods: The study utilized data from the 2019 to 2021 Korea Youth Risk Behavior Web-based Survey, which included 86,595 man and 80,504 woman participants. The number of independent variables stood at 44. SPSS was used to conduct Rao-Scott χ² tests and complex sample t-tests. Modeling was performed using the random forest algorithm in Python. Performance evaluation of each model included assessments of precision, recall, F1-score, receiver operating characteristics curve, and area under the curve calculations derived from the confusion matrix. Results: The prevalence of sexual experiences initially decreased during the COVID-19 pandemic, but later increased. "Variable importance" for predicting sexual experiences, ranked in the top six, included week and weekday sedentary time and internet usage time, followed by ease of cigarette purchase, age at first alcohol consumption, smoking initiation, breakfast consumption, and difficulty purchasing alcohol. Conclusion: Education and support programs for promoting adolescent sexual health, based on the top-ranking important variables, should be integrated with health behavior intervention programs addressing internet usage, smoking, and alcohol consumption. We recommend active utilization of the random forest analysis method to develop high-performance predictive models for effective disease prevention, treatment, and nursing care.

• 한국치위생학회지
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• 제19권2호
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• pp.287-295
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• 2019

Objectives: The purpose of this study was to investigate the factors affecting subjective oral symptoms according to the gender of youth from multi-cultural families in Korea using data from the 14th (2018) Korean Youth Health Behavior Survey. Methods: The independent variables used in this study consisted of gender and sweet drink intake. The dependent variable was experience of subjective oral symptoms. Compensation variables consisted of general characteristics of school type, academic performance, economic status, drinking status, smoking status, and number of tooth brushings day before. The subjects of the study were 835 children of multi-cultural families whose parents were foreigners. All statistical analyses were performed by complex samples cross-tabulation analysis and complex samples logistic regression analysis. Statistical analysis was performed using the PASW statistical package 21.0 (Statistical Packages for Social Science Inc., Chicago, IL, USA). A significance level of 0.05 was used for statistical significance. Results: The composite sample logistic regression analysis showed that there was a statistically significant difference between gender and intake of sweet drinks in experience of subjective oral symptoms. Conclusions: These results suggest that factors influence subjective oral symptoms in Korean multi-cultural adolescents. Therefore, I hope that they will be used as basic data for the introduction and development of a customized oral health education program for improving oral health of multi-cultural adolescents.

• 대한두개안면성형외과학회지
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• 제22권3호
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• pp.148-153
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• 2021

Background: The zygomaticomaxillary complex (ZMC) has a protruded, convex shape and plays a vital role in determining the contour by affecting the width of the middle face. This study aimed to evaluate the efficiency of ZMC fracture reduction and explore detailed directions for outcome improvement. Methods: We conducted a retrospective study of patients diagnosed with unilateral ZMC fracture who underwent ZMC reduction surgery at a single hospital between January 2015 and May 2020. The primary outcome variable was facial asymmetry using the difference in the bilateral malar eminence (ME) position measured by computed tomography scan. The 3-dimensional distance (I_A, asymmetry index) and the distance in each dimension, D_x (anteroposterior distance), D_y (mediolateral distance), and D_z (superoinferior distance) were compared. Results: A total of 101 patients with ZMC fractures and 54 non-fracture patients were enrolled in the study. The mean age of the study sample was 43.49 years (control sample, 43.35 years), and the male-to-female ratio was 66.3:33.7 (control sample, 64.8:35.2). There were 53 and 48 patients with right and left ZMC fractures, respectively. The I_A was not statistically different between the two groups. In terms of position in each dimension, only D_x was significantly different between the two groups. Conclusion: The results show that overall facial asymmetry was recovered after ZMC reduction, but in certain dimension significant difference in ME position has still remained. For further improvement, treatment should be performed to relieve malar depression in the anteroposterior dimension.

• 대한통합의학회지
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• 제10권1호
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• pp.109-118
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• 2022

Purpose : The study to verify the effectiveness of the Soomchi combined marine healing program by analyzing the physical composition of the subjects, their blood lipids, and the effects of the program on their lung health-related variables, and heart rate variability variables. Methods : In the experiment, the Soomchi combined marine healing program was conducted for 5 hours a day, 5 days a week. on 15 participants. The results of their body composition, blood lipids, lactic acid, blood pressure, PEF, FEV1 and maximum oxygen intake were analyzed before and after the subjects completed the Soomchi program. For the statistical analysis, the mean and standard deviation (M±SD) of each variable were calculated using SPSS version 20 and an independent t-test was conducted to test for the amount of change in the participants before and after the Soomchi combined marine healing program. All significant levels were set to α=.05. As a result of the experiment Results : First, no statistically significant differences were found in the changes in body composition after the 5-day combined marine healing program was completed. Second, regarding the changes in blood component after the program was conducted, statistically significant differences were found in the lactic acid (p<.05). That is, the experimental group showed a significant decrease in lactic acid after the program whereas the control group showed a significant increase. Third, systolic blood pressure decreased significantly and while in PEF and FEV1 increased significantly in the experimental group after the program. Fourth, the LF of the control group significantly decreased after 5 days. Conclusion : After the Soomchi Lung Health Ocean Healing Program, positive physical changes were observed in the lung health variables and heart rate variability of the participants.

• International Journal of Computer Science & Network Security
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• 제21권7호
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• pp.211-220
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• 2021

The aim of the study is to implement a factor analysis of the determinants of pricing in a state-regulated competitive market using economic and mathematical modelling methods and to develop ways to improve the pricing environment of the market under study. The purpose of the work defines the main objectives: (i) to investigate the features of the competitive model of the Ukrainian flour market; (ii) to analyse the current price conjuncture of the flour market and the dynamics of the main determinants of pricing; (iii)to develop ways of improving the price situation on the flour market on the basis of the factor analysis on the results of economic and mathematical modelling. In order to ensure the reliability and validity of the research results, the following methods were applied: the logical-dialectical method of scientific knowledge in the study of the main theoretical aspects of flour market functioning, the method of logical generalisation and synthesis, comparison, factor analysis, correlation and regression analysis, the graphical method, etc. It has been shown that pricing in a state-regulated competitive market has its own characteristics. For example, in the flour market the price of goods cannot be influenced by producers (sellers) by any methods, therefore determinants of pricing by indirect influence have been taken into account. The five-factor power model of wheat flour price has been constructed. It was substantiated that the price of wheat flour in Ukraine is mostly influenced by consumer price index (0.92 %). The received complex model of wheat flour price may be used also for medium-term forecasting and working out the ways of price formation optimization in the flour market.