• The Korean Journal of Applied Statistics
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• v.34 no.3
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• pp.309-327
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• 2021

Dynamic treatment regimes (DTRs) are decision-making rules designed to provide personalized treatment to individuals in multi-stage randomized trials. Unlike classical methods, in which all individuals are prescribed the same type of treatment, DTRs prescribe patient-tailored treatments which take into account individual characteristics that may change over time. The Q-learning method, one of regression-based algorithms to figure out optimal treatment rules, becomes more popular as it can be easily implemented. However, the performance of the Q-learning algorithm heavily relies on the correct specification of the Q-function for response, especially in observational studies. In this article, we examine a number of double-robust weighted least-squares estimating methods for Q-learning in high-dimensional settings, where treatment models for propensity score and penalization for sparse estimation are also investigated. We further consider flexible ensemble machine learning methods for the treatment model to achieve double-robustness, so that optimal decision rule can be correctly estimated as long as at least one of the outcome model or treatment model is correct. Extensive simulation studies show that the proposed methods work well with practical sample sizes. The practical utility of the proposed methods is proven with real data example.

• Design Convergence Study
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• v.14 no.2
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• pp.1-16
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• 2015

As childhood obesity and nutrition imbalance emerge as social issues in South Korea today, the development of education materials on diets and nutrition has become important and has been attempted in diverse ways. The present study was conducted on early elementary school students with the objective of establishing directions for the design of personalized nutrition education materials that can promote a proper, balanced diet for children through application in daily life of knowledge acquired from self-learning linked to nutrition education that is taking place in their schools. For this purpose, a review of previous theoretical literature on nutrition education for early elementary students was performed. Survey questions were formulated based on the advice of field experts in medicine, education, and design and the survey was conducted among 110 children from 1st and 2nd grade in two elementary schools, one in Seoul and the other in Changwon. The results obtained from the user evaluation suggested that the early elementary school students showed positive reaction to nutrition education, had preference for the type of learning using multimedia-based contents and quiz activities, were willing to learn about calorie-adjusted meals, preferred the Gothic typeface and orange and green colors. Furthermore, they showed positive opinion on the use of numerical surveying method and pictorial style similar to actual appearance in connection with nutrition-related information representation. and preferences regarding learning styles and design elements

• Korea Journal of Hospital Management
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• v.7 no.1
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• pp.41-63
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• 2002

The purpose of this study is to analyze the interrelation of influential factors in organizational conflict and organizational commitment. The data for this study were collected through a self-administered survey with a structured Questionnaire to 1,167 subjects from several nursing staff members, administration staff members and medical technicians of six hospitals. In this analysis frequency test, t-test, ANOVA, hierarchical multiple regression and structural equation model were used. The main findings of this study are as follows. 1. Factors which influence organizational conflict were analyzed. The type of occupation and the year of service were socio-demographic variables which influenced organizational conflict positively. Adjusted R square was 0.03. Perceptions on organizational structure and organizational culture were analyzed with two- level variables that were added. The findings were as follows. Adjusted R square increased to 0.25. The year of service, internal process culture and rational goal culture were positive variables. The design of organizational structure, human relations culture and open system culture were negative variables. 2. Variables which influence organizational commitment were analyzed. Age and the year of service were positive variables, while academic background based on high school education was a negative variable. Adjusted R square was 0.16. Perceptions on organizational structure and organizational culture were analyzed with two-level variables that were added. The findings were as follows. The characteristics of organizational structure, human relations culture and organizational culture were positive variables. Adjusted R square increased to 0.55. The variables of organizational conflict were added in 3 steps. Findings were as follows. The variables of hierarchical conflict showed negative influence and were included in two-level influential variables. Adjusted R square increased to 0.56. 3. Structural equation model was analyzed in order to examine the relation between organizational structure and the variables of organizational culture, organizational conflict and organizational commitment. Thirteen path coefficients out of seventeen path coefficients were significant. Age had negative influence on organizational conflict and positive influence on organizational commitment. The year of service had positive influence on organizational conflict and organizational commitment. The design of organizational structure, human relations culture and open system culture had negative influence on organizational. conflict. They had positive influence on organizational commitment. Internal process culture and rational goal culture had positive influence on organizational conflict. Organizational conflict had negative influence on organizational commitment. The squared multiple correlation of this model was 25.1% in organizational conflict and 52.7% in organizational commitment. The conclusion of this study is as follows. Factors in organizational structure and organizational culture, rather than socio-demographic factors, had a stronger influence on the organizational conflict and organizational commitment of hospitals. In order to decrease organizational conflict, to increase organizational commitment and to maximize the effectiveness of hospital management, it is necessary to understand the overall relation between organizational structure, organizational culture, organizational conflict and organizational commitment, with the effort of improving personalized factors and individual factors of organization management.

• Journal of agricultural medicine and community health
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• v.29 no.2
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• pp.287-301
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• 2004

Objectives: The development of internet programs for smoking cessation was motivated to quit smoking in the large group of smokers. This personalized program consisted of tailored message to consider the smokers characteristics, and contain the informations on the outcomes of smoking cessation and the skills to be used in the quit attempts. The purpose of this study was to develop the internet management program and information push-delivery system for smoking cessation to encourage the personal intention to quit smoking. Methods: We conducted in 3 steps as developing push service to encourage intention of smoking cessation, analyzing problems of smoking cessation program through the pilot test and suggesting improvements by implication stages. Results: This program is delivered for 30 days. if the participants do not fail to quit smoking. The contents consisted of 13 stages which were divided on starting period. practical period, maintenance period and success period. And push service afforded the tailored message to participants using their e-mail. According to the evaluation of pilot test, the problems of internet information push-delivery service for smoking cessation were the over-tasks per visiting time, recording style of participants, difficulty of terms and sentences, lack of visual effects, absence of follow-up module and unsuitable link with main homepage. Improvements were divided on 3 stages by implication period. The first stage included the immediate improvements as improving link with homepage, modifying menu of smoking information and upload file of notice part. The second stage included the short term improvements as alleviating condition of withdrawal, coordinating start stage of retrial, modifying errors of information push-delivery service and addition of educational materials. The third stage included the long term improvements as development of follow-up module, cost-effectiveness evaluation, reducing contents quantity, introduction of checking style, compensation of graphics effect and review for SMS utilization. Conclusions: This program contribute to improving smoking cessation rate. Therefore this program should be tested in a community to evaluate the effectiveness. To promote the effectiveness, this program should be developed the contents and the strategies for various targets, and established the follow-up system for ex-smokers.

• Journal of Genetic Medicine
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• v.8 no.2
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• pp.89-99
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• 2011

Over the years Korean health care system has improved in delivery of quality care to the general population for many areas of the health problems. The system is now being recognized in the world as the most cost effective one. It is covered by the uniform national health insurance policy for which most people in Korea are mandatory policy holders. Genetic counseling service, however, which is well recognized as an integral part of clinical genetics service deals with diagnosis and management of genetic condition as well as genetic information presentation and family support, is yet to be delivered in comprehensive way for the patients and families in need. Two major obstacles in providing genetic counseling service in korean health care system are identified; One is the lack of recognition for the need for genetic counseling service as necessary service by the national health insurance. Genetic counseling consumes a significant time in delivery and the current very low-fee schedule for physician service makes it very difficult to provide meaningful service. Second is the critical shortage of qualified professionals in the field of medical genetics and genetic counseling who can provide the service of genetic counseling in clinical setting. However, recognition and understanding of the fact that the scope and role of genetic counseling is expanding in post genomic era of personalized medicine for delivery of quality health care, will lead to the efforts to overcome obstacles in providing genetic counseling service in korean health care system. Only concerted efforts from health care policy makers of government on clinical genetics service and genetic counseling for establishing adequate reimbursement coverage and professional communities for developing educational program and certification process for professional genetic counselors, are necessary for the delivery of much needed clinical genetic counseling service in Korea.