• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.5
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• pp.527-547
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• 2009

Moving object management is widely used in traffic, logistic and data mining applications in ubiquitous environments. It is required to analyze spatio-temporal data and trajectories for moving object management. In this paper, we proposed a novel index structure for spatio-temporal aggregation of trajectory in a constrained network, named aCN-RB-tree. It manages aggregation values of trajectories using a constraint network-based index and it also supports direction of trajectory. An aCN-RB-tree consists of an aR-tree in its center and an extended B-tree. In this structure, an aR-tree is similar to a Min/Max R-tree, which stores the child nodes' max aggregation value in the parent node. Also, the proposed index structure is based on a constrained network structure such as a FNR-tree, so that it can decrease the dead space of index nodes. Each leaf node of an aR-tree has an extended B-tree which can store timestamp-based aggregation values. As it considers the direction of trajectory, the extended B-tree has a structure with direction. So this kind of aCN-RB-tree index can support efficient search for trajectory and traffic zone. The aCN-RB-tree can find a moving object trajectory in a given time interval efficiently. It can support traffic management systems and mining systems in ubiquitous environments.

• Research in Community and Public Health Nursing
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• v.28 no.4
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• pp.463-471
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• 2017

Purpose: This study aimed to identify the association between psychosocial work environment and depressive symptoms among Korean teachers. Methods: Data on 235 elementary school teachers and 341 middle and high school teachers was obtained from the 2014 Korean Working Condition Survey. The effect of psychosocial work environment on depressive symptoms was determined by multiple logistic regression analyses. Results: The prevalence of depressive symptoms was 18 % in elementary school teachers and 24 % in middle and high school teachers. When adjusted for demographics and other socio-psychological and environmental factors, 'social community at work' served as a protection factor for Korean teachers' depressive symptoms. In addition, 'cognitive demands' in elementary school teachers and 'social support from supervisors' in middle and high school teachers were found to be predictors of depressive symptoms. Conclusion: Interventions to increase 'social community at work' and 'social support from supervisors', and to decrease 'cognitive demands' may be helpful for Korean teachers at risk of depression.

• Journal of the Korean Society of School Health
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• v.25 no.2
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• pp.168-174
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• 2012

Purpose: The purpose of this study was to identify the prevalence of counselling need for school life problem in middle school students and to investigate characteristics of their family and school life. Methods: Subjects were 7,136 middle school students in Seoul. Data were from 2010 Student Health Examination in Seoul. Cross-sectional study using secondary data was performed. Descriptive, t-test and multiple logistic regression were conducted. Results: 7.2% among subjects required counselling for their school life problem. By demographics, the odds ratios of counselling need were 2.2 times in female, and 1.59 and 1.41 times in 8th and 9th grade vs 7th grade. By region, those of Dongbukbu (Northeast), Seobu (West), and Jungbu (Central) vs Kangnam (South of River) district were 0.46, 0.25, and 0.57 times. With regard to family and school life characteristics, those of inflicted violence, the bullying, family apprehension, and consideration of away from home were 3.38, 3.75, 2.08, and 2.40 times, while that of students having person to discuss was only 0.62 times. Conclusion: It is necessary to activate the school counselling program, especially enforcing support system, not only to enforce resilience of student, but also to decrease the health problems in family and school life.

• Korean Journal of Agricultural Science
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• v.42 no.3
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• pp.277-283
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• 2015

This study aims at analyzing determinants of non-farming income activities of female farmers, and presenting how to support their participation in non-farming activities. The result of logistic regressive analysis whose subjects are female farmers in the Chungnam area indicates that human and economic capital variables that can predict non-farming income activity participation statistically significantly are persons at the age of 40s to 50s and female farmers who returned to the rural areas. Farming characteristic variables are households that receive subsidiary and participate in two different types of farming whose main farming is rice. The female farmers who spend longer hours doing household chores participate in non-farming income activities more actively. In terms of policy and on-site response variables, the interest in farming and farming businesses shows positive relation, and that of farming and community organization participation presents negative relation. These analysis results indicate that the local government must present the policy that can select non-farming income activity participation groups strategically. This study suggest that it is necessary to expand community centered-non-farming income activities, and to expand or make laws to support female farmer's participation in non-farming activities.

• Nuclear Engineering and Technology
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• v.52 no.7
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• pp.1436-1442
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• 2020

Nuclear infrastructure systems play an important role in national security. The functions and missions of nuclear infrastructure systems are vital to government, businesses, society and citizen's lives. It is crucial to design nuclear infrastructure for scalability, reliability and robustness. To do this, we can use machine learning, which is a state of the art technology used in various fields ranging from voice recognition, Internet of Things (IoT) device management and autonomous vehicles. In this paper, we propose to design and develop a machine learning algorithm to perform predictive maintenance of nuclear infrastructure. Support vector machine and logistic regression algorithms will be used to perform the prediction. These machine learning techniques have been used to explore and compare rare events that could occur in nuclear infrastructure. As per our literature review, support vector machines provide better performance metrics. In this paper, we have performed parameter optimization for both algorithms mentioned. Existing research has been done in conditions with a great volume of data, but this paper presents a novel approach to correlate nuclear infrastructure data samples where the density of probability is very low. This paper also identifies the respective motivations and distinguishes between benefits and drawbacks of the selected machine learning algorithms.

• The Journal of Information Systems
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• v.27 no.3
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• pp.63-80
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• 2018

Purpose The purpose of this study is to build a machine learning-based customer classification model to promote customer expansion effect of the free sample promotion. Specifically, the proposed model classifies potential target customers who are expected to purchase the products included in the free sample promotion after receiving the free samples. Design/methodology/approach This study proposes to build a customer classification model for determining customers suitable for providing free samples by using various machine learning techniques such as logistic regression, multiple discriminant analysis, case-based reasoning, decision tree, artificial neural network, and support vector machine. To validate the usefulness of the proposed model, we apply it to a real-world free sample-based target marketing case of a Korean major cosmetic retail company. Findings Experimental results show that a machine learning-based customer classification model presents satisfactory accuracy ranging from 70% to 75%. In particular, support vector machine is found to be the most effective machine learning technique for free sample-based target marketing model. Our study sheds a light on customer relationship management strategies using free sample promotions.

• Korean Journal of Health Education and Promotion
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• v.29 no.3
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• pp.63-74
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• 2012

Objectives: We aim to investigate association between health behavior, interpersonal/organizational environment and job stress among government officials. Methods: Through health examination and a survey, this cross sectional study investigated 543 government officials working at Central Government Complex in Seoul, Korea. Health behaviors included alcohol drinking, smoking, moderate exercise and food frequency. Interpersonal environment was measured by health behavior practices of significant others and social support for health promotion. And the measures of organizational environment included facilities for exercise, health related norms and health supportive organizational systems. Job stress was assessed by short version of Korean Occupational Stress Scale(KOSS). Results: The level of job stress among female officials was higher than that of male officials. Multivariate logistic model suggested that higher job stress in male officials was significantly associated with lower position(OR=0.267, p<.01) less grain intake(OR=0.642, p<.05), lower level of social support(OR=0.810, p<.01) and abdominal obesity(OR=2.407, p<.05). On the contrary, female officials' stress level was negatively associated with healthy organizational environment(OR=0.725, p<.05). Conclusions: It is suggested that addressing job stress require tailoring intervention by gender characteristics and integration of interpersonal and organizational level approaches.

• Korean Journal of Health Education and Promotion
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• v.27 no.4
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• pp.61-72
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• 2010

Objectives: This study was peformed to identify the related factors on Vietnamese immigrant women's reproductive health problems. Survey Participants were 231 immigrant vietnamese woman who lived at six cities in Korea. Methods: The comprehensive PRECEDE model comprised of diagnosis and planning curricular targeted or immigrant women aged 15-49. Data collection was conducted by face-to-face interview survey. Results: 1. The influential variables of recognition of reproductive health problems from the logistic analysis were using contraceptives (p=0.002), relationships with partners (p=0.000), the need of family planning (p=0.007), social support (p=0.009). This means that they experienced reproductive health problems when they did not use contraceptives, did not need family planning, did not receive social support and had close relationships with their partners. Conclusion: The basic data were provided for prevention of reproductive health problems such as unwanted pregnancy and abortion, as well as improved understanding of the different views on pregnancy, birth culture and sexual and reproductive health between Korea and Vietnam.

• Korean Journal of Health Education and Promotion
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• v.30 no.2
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• pp.41-53
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• 2013

Objectives: As the size of elderly population living alone grows, socioeconomic diversity has also increased. This study examined if social risk factors of poor self-rated health were distinguishable between the low income elderly and their non-low income counterparts both living alone. Methods: The '2006 Elderly Health Interview Survey' conducted by D-gu in Seoul was utilized. We divided the elderly living alone into two groups depending on their economic status: low income and non-low income. Employing logistic regression, we analyzed the associations of poor self-rated health with socio-demographic factors, health-related factors, social support, the relations with children, social activities, welfare service use, and the perception of neighborhood safety. Results: Proportion of rating one's own health being poor was different between two populations. Social support was important for the self-rated health of the non-low income elderly, while welfare service use, the perception of neighborhood safety, and the relations with children were noticeable for the low income elderly. Conclusions: To better understand the health need of elderly population living alone, their heterogeneity in socioeconomic characteristics should be taken into account.

• Korean Journal of Occupational Health Nursing
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• v.21 no.1
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• pp.18-26
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• 2012

Purpose: This study tried to explore factors influencing on job maintenance of the mentally disabled who employed before. The subjects of this study were the mentally disabled who participated in community mental health center and social rehabilitation center, there had experienced a job in the past. Methods: The number of community centers were 27 places, there were located in different region. The number of participants were 221 persons agreed to this study. Data was analyzed by Mean, SD and logistic regression analyzation using SPSS/WIN 14.0. Results: General character such as age was significant factor. Monthly pay and working a day in the midst of job related factors were significant. Moreover, job rehabilitation program satisfaction rate and social support revealed significant factors. Conclusion: On the basis of results, Job rehabilitation programs for job maintenance of the mentally disabled should be development and establish mediate strategies to improve social support to them.