• Journal of Korea Water Resources Association
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• v.57 no.1
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• pp.9-19
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• 2024

As using public monitoring data, analysing a trends of water quality change, establishing a criteria to determine abnormal status and constructing a regression model that can predict Chlorophyll-a, an indicator of eutrophication, was studied. Accordingly, the three freshwater lakes were selected, approximately 20 years of water quality monitoring data were analyzed for periodic changes in water quality each year using regression analysis, and a method for determining abnormalities was presented by the standard deviation at confidence level 95%. By calculating the temporal change rate of Chlorophyll-a from irregular observed data, analyzing correlations between the rate and other water quality items, and constructing regression models, a method to predict changes in Chlorophyll-a was presented. The results of this study are expected to contribute to freshwater lake water quality management as an approximate water quality prediction method using the statistical model.

• Information Systems Review
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• v.22 no.1
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• pp.167-182
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• 2020

Ambidexterity in organizations, in general, is interpreted as flexibility that enables organizational innovation, which is important for survival in a competitive market. It applies to individual workers as well since the ambidexterity of explorational and exploitational IS use will enable the flexible transition between dynamic and operational work, and hence, increase the work performance. The current study will therefore investigate the individual levels of exploratory and exploitative IS use, as well as the complementary relationship between exploratory and exploitative IS use. In a third step, the differential influence of IS on work performance will be evaluated. The current study validated that complementary fit of IS use exploration and IS use exploitation increases performance. Polynomial regression and surface analysis are used to validate the incongruence of IS use pattern. They showed that the incongruence of ambidexterity is composed of two types of divergent vs. convergent ambidexterity which depends on the type of work that need dynamic or operational capability.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.3
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• pp.95-101
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• 2024

The numberlink puzzle(NLP), which non-crossings with other numbers of connection in connecting lines through empty cells between a given pair of numbers, is an NP-complete problem with no known way to solve the puzzle in polynomial time. Until now, arbitrary numbers have been selected and puzzles have been solved using trial-and-error methods. This paper converts empty cells into vertices in lattice graphs connected by edge between adjacent cells for a given problem. Next, a straight line was drawn between the pairs of numbers and divided into groups of numbers where crossing occurred. A bypass route was established to avoid intersection in the cross-number group. Applying the proposed algorithm to 18 benchmarking data showed that the puzzle could be solved with a linear time complexity of O(n) for all data.

• Korean Journal of Social Welfare
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• v.58 no.4
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• pp.141-168
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• 2006

The present study explored and compared the risk factors of two subtypes of maritally violent men with those of a nonviolent comparison group. One type of batterers consisted of a community sample, and the other was sought from the criminal justice system. The identities of the male community batterers were not exposed to the society since their victims did not contact any of the social service agents related to domestic violence. To identify the different characteristics associated with two subtypes of woman abusers, a total of 152 nonviolent men, 82 male community batterers, and 336 offenders in a criminal justice system were considered. The results of the descriptive analysis showed that the level of physical violence of the community batterers was two times lower than that of the batterers who received legal punishments. The results of the multinominal logistic regression were as follows: (1) The variables that distinguished the male community batterers from the nonviolent men were the use of physical violence towards children, marital decision power, and income. (2) Four factors had been found to distinguish batterers in the criminal justice system from nonbatterers, namely: attitudes towards woman battering, education, violence towards children, and level of jealousy. (3) The community batterers showed a higher level of education and of stress as well as a longer period of marital relationship compared to the batterers in the criminal justice system. On the other hand, the batterers who received legal punishments had more severe alcohol problems and had an accepting attitude towards the use of violence. This study also investigated psychopathology among batterers using MCMI-III, based on 333 subjects. In terms of the mean scores, there were no subscales associated with personality pathology in all the male groups. Based on the logit model, the community batterers showed a stronger tendency towards having a passive-aggressive personality than did their counterparts, and they recorded a higher level of narcissism compared to the court-referred battering men. Post-traumatic stress was the only symptom that distinguished the batterers who received legal punishments from the other groups. The theoretical and practical implications of these results were pointed out and discussed in the paper.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.6
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• pp.59-76
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• 2019

Most technology-based entrepreneurship(TBE) go through an process of decline or disappear without overcoming the valley of death(VoD). The purpose of this study is to identify the growth dimension of TBE and to test the influence of firms activities on firms growth over time. This study identified the two-dimensional growth dimension divided by size and profit through exploratory factor analysis(EFA) of a number of growth indicators. Then, we defined the discrete state of growth firm in four states, divided by size and profit, and five states, including the closure of business. Multi-nomial logit model is used to predict the effect of TBE activities on a discrete state of growth firm(size×profit, closure of business) based on multiple independent variables. The independent variables are based on five representative firms activities: employment, marketing, R&D, financial activities, and general management activities. The growth stage of TBE over time has been categorized into three stages: early stage, middle stage, and late stage of business, taking into account the main periods during which the survival rate of startups sharply decreases. The analytical data of this study was based on the secondary data of the start-up supporting companies of government and public institutions. The subjects of analysis were TBE within 10 years. As a result of the empirical analysis, the employment and marketing activities of TBE show that early and mid-term activities had an effect on the state of firms growth. However, if there is a difference, employment activities have both positive and negative effects, while marketing activities have only a positive effect on size and profit growth. And besides, R&D activities, financial activities, and general management activities throughout the entire process of firms growth were found to be firms activities that have both positive and negative effects on firms growth. In addition, the age of the founder, the firms' industry, and the geographic location of the firms, which are general characteristics of the company, were found to have a distinctive effect on the growth status of the firms according to the growth stage.

• Applied Biological Chemistry
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• v.43 no.1
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• pp.7-11
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• 2000

The effects of fermentation temperature$(0{\sim}l5^{\circ}C)$ and salt concentration$(1.5{\sim}4.0%)$ on the fermentation property of Chinese cabbage Kimchi were analyzed by response surface methodology. The pH decreased and acidity increased with increasing fermentation time. The reduction and increment velocities of pH and acidity were increased by increasing fermentation temperature and decreasing salt concentration. The optimum pH 4.2 was reached within $14{\sim}24$ days at $5{\sim}15^{\circ}C$, while pHs of 24 days at $0{\sim}5^{\circ}C$ were still lower value than 4.2. The effect of salt concentration more affected terminal fermentation period than initial fermentation period. The maximum edible acidity, 0.75%, was reached within 8 days at $15^{\circ}C$, while acidifies of 24 days at $0^{\circ}C$ were $0.35{\sim}0.43%$. The effects of salt concentration at $0^{\circ}C$ was higher than those at $15^{\circ}C$. The fermentation time, fermentation temperature and salt concentration were the first, second and third affecting factors on the pH and acidity of Kimchi. Based on the coefficients of determination, pH and acidity were highly fitted to the experimental data$(r^2>0.9276)$. For the suitable acidity range, $0.40{\sim}0.75%$, the edible period of Kimchi at $15^{\circ}C,\;10^{\circ}C\;and\;5^{\circ}C$ were 4 days, 10 days and 18 days at the 2.75% of salt concentration, respectively. The edible period increased from 14 days to 19 days with increased salt concentration from 1.50% to 4.00% at $5^{\circ}C$ of fermentation temperature.

• Korean Journal of Social Welfare Studies
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• v.44 no.3
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• pp.85-112
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• 2013

This study aims to understand the developmental trajectories of life satisfaction among retirees and to examine what factors differentiate different trajectory classes. This study used three waves of longitudinal data from Korean Retirement and Income Study and data collected every two years(2005, 2007, and 2009). Subjects were respondents aged 50-69 who identified to be retired between wave 1 and wave 2. Finally, this study used 243 respondents for final data analysis. Life satisfaction was measured by seven items. The latent class growth model and multiple logistic regression model were used for data analysis. This study identified three distinct trajectory classes: high stable class(47.7%), high at the early stage but decreased class(42.8%), and low at the early stage and then decreased class(9.5%). This study founded that approximately 50% of the retirees experienced the decline of life satisfaction after retirement and about 10% of the sample was the most vulnerable group. This study analyzed what factors make different among the distinct trajectory groups. As a results, retirees who experienced the improvement in health change were more likely to be in 'high stable class' compared to 'hight at the early stage but decreased class'. In addition, retirees who were less educated, maintained the same health status rather than the improvement, worked as a temporary or a day laborer, and had less household income were more likely to belong to 'low at the early stage and then decreased class' relative to 'high stable class'. This study suggests that there are distinct three trajectories on life satisfaction among the retirees and finds out factors differentiating between trajectory groups. Based on these findings, the study discusses the implications for social work practice and further study.

• Therapeutic Science for Rehabilitation
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• v.10 no.2
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• pp.75-93
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• 2021

Objective : The aim of this study was to identify subgroups of older adults with respect to their lifestyle patterns and examine the characteristics of each subgroup in order to provide a basic evidence for improving the health and quality of life. Methods : This cross-sectional study was conducted in South Korea. Community-dwelling older adults (n=184) above the age of 65 years were surveyed from April 2019 to May 2019. This study used latent profile analysis to examine the subgroups. Chi-squared (χ²) and multinomial logistic regression measures were then used to analyze individual characteristics and influencing factors. Results : The pattern of physical activity which is one of the lifestyle domains in elderly was categorized into three types: 'passive exercise type (31.1%)', 'low intensity exercise type (54.5%)', and 'balanced exercise type(14.5%)'. Activity participation was divided into three patterns: 'inactive type (12%)', 'self-management type (61%)', and 'balanced activity participation type (27%)'. In terms of nutrition, there were only two groups: 'overall malnutrition type (13.5%)' and 'balanced nutrition type (86.5%)'. Furthermore, as a result of the multinomial logistic regression analysis to understand the effects of lifestyle types on the health and quality of life of the elderly, it was confirmed that the health and quality of life were higher in those following an active and balanced lifestyle. In addition, gender, education level and residential area were analyzed as predictive factors. Conclusion : The health and quality of life of the elderly can be improved when they have balanced lifestyle. Therefore, an empirical and policy intervention strategy should be developed and implemented to enhance the health and quality of life of the elderly.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.4
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• pp.42-51
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• 2020

This study was performed to support the 6th forest basic planning by Korea Forest Service as predicting the change of forestland area by the transition of land use type in the future over 35 years in South Korea. It is very important to analyze upcoming forestland area change for future forest planning because forestland plays a basic role to predict forest resources change for afforestation, production and management in the future. Therefore, the transitional interaction between land use types in future of South Korea was predicted in this study using econometrical models based on past trend data of land use type and related variables. The econometrical model based on maximum discounted profits theory for land use type determination was used to estimate total quantitative change by forestland, agricultural land and urban area at national scale using explanatory variables such as forestry value added, agricultural income and population during over 46 years. In result, it was analyzed that forestland area would decrease continuously at approximately 29,000 ha by 2027 while urban area increases in South Korea. However, it was predicted that the forestland area would be started to increase gradually at 170,000 ha by 2050 because urban area was reduced according to population decrement from 2032 in South Korea. We could find out that the increment of forestland would be attributed to social problems such as urban hollowing and localities extinction phenomenon by steep decrement of population from 2032. The decrement and increment of forestland by unbalanced population immigration to major cities and migration to localities might cause many social and economic problems against national sustainable development, so that future strategies and policies for forestland should be established considering such future change trends of land use type for balanced development and reasonable forestland use and conservation.

• 한국노년학
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• v.29 no.4
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• pp.1361-1381
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• 2009

There have lately been a variety of social issues in our society due to rapid social changes. Specifically, how to approach elderly people who suffer from dementia is never an easy task, and few in-depth studies have ever focused on their quality of life due to that. The purpose of this study was to examine the quality of life of elderly people with dementia and the relationship between their quality of life and the environments of facilities for them in an attempt to lay the foundation for the development of compatible programs tailored to the environments of the facilities and for relevant policy setting. It's ultimately meant to improve the quality of life of the elderly with dementia and the environments of facilities for them. The subjects in this study were elderly people with dementia who were housed in senior residential and medical welfare facilities in Daegu and Gyeongsangbukdo. The collected data were analyzed with a SPSS 12.0 program, and frequency analysis, cross-tabs and multiple logistic regression analysis were utilized. As a result, facility environments were identified as one of the variables that had a significant impact on the quality of life of the elderly people with dementia. There are some suggestions about how to boost their quality of life: First, good environments should be prepared in consideration of the characteristics of elderly people with dementia in order for themto be satisfied with their own quality of life, and the way of looking at their potentials should be changed. Second, it's found that main caregivers affected the quality of life of the elderly people with dementia, and the kind of programs that focus on the improvement of the relationship between elderly people with dementia and their main caregivers is required. Third, there should be a change in the environments of the facilities. The facilities should be well equipped to successfully respond to the symptoms of elderly people with dementia. To redress their poor accessibility to the facilities, infrastructure involving nursing homes and professional personnels should be built by utilizing the Internet, and the facilities and local community should make concerted efforts to provide quality care to elderly people in want of it.