• Journal of Intelligence and Information Systems
• /
• v.26 no.2
• /
• pp.43-56
• /
• 2020

Recommender systems help users make the best choice among various options. Especially, recommender systems play important roles in internet sites as digital information is generated innumerable every second. Many studies on recommender systems have focused on an accurate recommendation. However, there are some problems to overcome in order for the recommendation system to be commercially successful. First, there is a lack of transparency in the recommender system. That is, users cannot know why products are recommended. Second, the recommender system cannot immediately reflect changes in user preferences. That is, although the preference of the user's product changes over time, the recommender system must rebuild the model to reflect the user's preference. Therefore, in this study, we proposed a recommendation methodology using topic modeling and sequential association rule mining to solve these problems from review data. Product reviews provide useful information for recommendations because product reviews include not only rating of the product but also various contents such as user experiences and emotional state. So, reviews imply user preference for the product. So, topic modeling is useful for explaining why items are recommended to users. In addition, sequential association rule mining is useful for identifying changes in user preferences. The proposed methodology is largely divided into two phases. The first phase is to create user profile based on topic modeling. After extracting topics from user reviews on products, user profile on topics is created. The second phase is to recommend products using sequential rules that appear in buying behaviors of users as time passes. The buying behaviors are derived from a change in the topic of each user. A collaborative filtering-based recommendation system was developed as a benchmark system, and we compared the performance of the proposed methodology with that of the collaborative filtering-based recommendation system using Amazon's review dataset. As evaluation metrics, accuracy, recall, precision, and F1 were used. For topic modeling, collapsed Gibbs sampling was conducted. And we extracted 15 topics. Looking at the main topics, topic 1, top 3, topic 4, topic 7, topic 9, topic 13, topic 14 are related to "comedy shows", "high-teen drama series", "crime investigation drama", "horror theme", "British drama", "medical drama", "science fiction drama", respectively. As a result of comparative analysis, the proposed methodology outperformed the collaborative filtering-based recommendation system. From the results, we found that the time just prior to the recommendation was very important for inferring changes in user preference. Therefore, the proposed methodology not only can secure the transparency of the recommender system but also can reflect the user's preferences that change over time. However, the proposed methodology has some limitations. The proposed methodology cannot recommend product elaborately if the number of products included in the topic is large. In addition, the number of sequential patterns is small because the number of topics is too small. Therefore, future research needs to consider these limitations.

• Journal of dental hygiene science
• /
• v.18 no.6
• /
• pp.327-339
• /
• 2018

This study aimed to provide basic data for establishing the clinical basis for dental hygienist-led dental hygiene process of care by identifying multiple risk factors for self-support program participants in Gangneung city; we also compared oral health status and behavioral changes through customized oral health care. Four dental hygienists who were evaluated for degree of conformity provided dental hygiene process of care to eight self-support program participants who were selected as having an oral health risk among people in the self-support center. The clinical indicators measured during dental hygiene assessment and evaluation and behavioral changes due to dental hygiene intervention were compared and analyzed. With respect to clinical indicators, at the time of probe, the retention rate of patients with gingival bleeding decreased from 61.4% to 14.7% after intervention (p=0.004). Furthermore, the retention rate of patients with a periodontal pocket >4 mm decreased from 15.6% to 5.8% (p=0.001). The average modified O'Leary index of the patients improved from 23 to 40 (p=0.002). Previously, all eight subjects used the vertical or horizontal method of brushing; after dental hygiene care interventions regarding method and frequency of toothbrushing, use of oral care products, and individual interventions, they started using the rolling or Bass method of toothbrushing. Four of eight subjects reported using interdental toothbrushes after intervention. As a result of applying the change model to the transtheoretical behavior change of the subject, the result of strengthening the health behavior was confirmed. For promotion of oral health by the prevention-centered incremental oral health care system, dental hygienist-led dental hygiene management and maintenance is essential. It is thought that continuous research, such as for feasibility evaluation, cost benefit analysis, and preparation of legal systems, is needed to establish and activate dental hygiene management.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.47 no.2
• /
• pp.13-27
• /
• 2019

This study shows the changes in the space created by the planning and leisure activities of Hangang River Park, focusing on the Yeouido portion of the Hangang River Park, which has the most users and the greatest degree of planning. The relationship between planning, behavior, and space changes are explained based on Giddens's Structural Theory. As research material, Hangang River Park plans and satellite photos were interpreted and newspaper articles were used to identifying the space changes and their causes, and a model of the space changes was derived through the application of the theory. The flow of space change in the Yeouido portion of the Hangang River Park due to planning and leisure activities is as follows. In the 1970s, the first sports spaces are made due to need from residents near the riverside, but huge plans for the utilization of the entire space were not realized. In the 1980s, leisure spaces were planned and developed through a comprehensive plan. Various sports spaces were built, but the environment of the spaces became a slum. In the 1990s, various leisure activities were revitalized due to the revision of the legal system, regulations on the usage of space, and space maintenance, and from the late 1990s, ecological issues arose along the Hangang River. In the 2000s, there was an overall space improvement project directed by two comprehensive plans, and cultural and ecological issues appeared in the Hangang River Park plans. However, actual leisure spaces were developed along with the promotion of large-scale activities. Regarding the structuration theory, elements of interaction, modality, and structure are the aspects of space changes in the Yeouido portion Hangang River Park. As the flow of the space change, the proportions of the comprehensive plan and the individual plans were similar. The comprehensive plan was influenced by the change of public businesses and the proliferation of large-scale activities. Individual plans were influenced by the user's activities and opinions. However, both plans were influenced by the users and suppliers. The leisure space of the Hangang River Park can be viewed as a social space, in terms of the structuring as a theory due to the user repeatedly changing the use of the space. The purpos of this study is to investigate the changes in the Hangang River Park space through planning and leisure activities. Through this study, we can understand the characteristics of the Hangang River Park in planning the leisure activity space.

• Korean Chemical Engineering Research
• /
• v.57 no.5
• /
• pp.637-651
• /
• 2019

In the event of a major accident such as an explosion in a refinery or a petrochemical plant, it has caused a serious loss of life and property and has had a great impact on the insurance market. In the case of catastrophic incidents occurring in process industries such as refinery and petrochemical plants, only the proximate causes of loss have been drawn and studied from inspectors or claims adjustors responsible for claims of property insurers, incident cause investigators, and national forensic service workers. However, it has not been done well for conducting root cause analysis (RCA) and identifying the factors that contributed to the failure and establishing preventive measures before leading to chemical plant's catastrophic incidents. In this study, the criteria of warning signs on CCPS catastrophic incident waning sign self-assessment tool which was derived through the RCA method and the contribution factor analysis method using the swiss cheese model principle has been reviewed first. Secondly, in order to determine the major incident warning signs in an actual chemical plant, 614 recommendations which have been issued during last the 17 years by loss control engineers of global reinsurers were analyzed. Finally, in order to facilitate the assessment index for catastrophic incident warning signs, the criteria for the catastrophic incident warning sign index at chemical plants were grouped by type and classified into upper category and lower category. Then, a catastrophic incident warning sign index for a chemical plant was developed using the weighted values of each category derived by applying the analytic hierarchy process (pairwise comparison method) through a questionnaire answered by relevant experts of the chemical plant. It is expected that the final 'assessment index for catastrophic incident warning signs' can be utilized by the refinery and petrochemical plant's internal as well as external auditors to assess vulnerability levels related to incident warning signs, and identify the elements of incident warning signs that need to be tracked and managed to prevent the occurrence of serious incidents in the future.

• Journal of Korean Society of Forest Science
• /
• v.111 no.4
• /
• pp.461-472
• /
• 2022

Natural and anthropogenic factors cause forest types to continuously change. Since the ratio of forest area by forest type is important information for identifying the characteristics of national forest resources, an accurate understanding of the prospect of forest type change is required. The study aim was to use National Forest Inventory (NFI) time-series data to understand the characteristics of forest type change and to estimate future prospects of nationwide forest type change. We used forest type change information from the fifth and seventh NFI datasets, climate, topography, forest stand, and disturbance variables related to forest type change to analyze trends and characteristics of forest type change. The results showed that the forests in Korea are changing in the direction of decreasing coniferous forests and increasing mixed and broadleaf forests. The forest sites that were changing from coniferous to mixed forests or from mixed to broadleaf forests were mainly located in wet topographic environments and climatic conditions. The forest type changes occurred more frequently in sites with high disturbance potential (high temperature, young or sparse forest stands, and non-forest areas). We used a climate change scenario (RCP 8.5) to establish a forest type change model (SVM) to predict future changes. During the 40-year period from 2015 to 2055, the SVM predicted that coniferous forests will decrease from 38.1% to 28.5%, broadleaf forests will increase from 34.2% to 38.8%, and mixed forests will increase from 27.7% to 32.7%. These results can be used as basic data for establishing future forest management strategies.

• Journal of agricultural medicine and community health
• /
• v.47 no.2
• /
• pp.90-98
• /
• 2022

Objective: This study aimed to provide basic data for preventing and managing sarcopenia by identifying the relationship between sarcopenia, malnutrition, and psychosocial factors among the elderly in the community. Methods: The study included 1,019 subjects aged 60 and over. "Possible sarcopenia" was defined by low handgrip strength with or without reduced physical performance. Nutrition was evaluated according to the mini nutrition assessment (MNA), and the psychosocial factors examined were self-efficacy, social isolation, fear of falling, and social capital (trust and participation). A logistic regression analysis was also performed on the relationship between risk of malnutrition, psychosocial factors, and sarcopenia. Results: MNA was significantly associated with social participation (OR = 1.747, p <0.001), fear of falling (OR = 2.905, p <0.001), and self-efficacy (high/low, OR = 0.654, p = 0.011). In model 3, which included both MNA and psychosocial factors, sarcopenia was significantly associated with MNA (OR = 2.529, p <0.001) and fear of falling (OR = 1.544, p = 0.045). Compared with the low self-efficacy group, the high group (OR = 0.589, p = 0.009) was significant. The factors related to possible sarcopenia include risk of malnutrition, fear of falls, and low self-efficacy. Conclusion: It will be necessary to improve self-efficacy so that individuals feel they can do activities of daily living themselves and to reduce their fear of falling through muscle strength and balance exercises. Finally, it is also necessary to increase regular participation in community social activities.

• Journal of the Korean Society of Radiology
• /
• v.17 no.2
• /
• pp.257-265
• /
• 2023

The purpose of this study was to vaccinate every year according to the general characteristics of COVID-19, whether to vaccinate every year according to the vaccination experience, whether to vaccinate every year according to knowledge/attitude about vaccination, and negative responses to the vaccinate every year In order to understand the factors affecting the vaccination physician every year by identifying the factors of Statistical analysis is based on general characteristics, variables based on vaccination experience, and knowledge/attitudes related to vaccination. The doctor calculates the frequency and percentage, A square test (-test) was performed, and if the chi-square test was significant but the expected frequency was less than 5 for 25% or more, a ratio difference test was performed with Fisher's exact test. Through multiple logistic regression analysis using variables that were significant in simple analysis, a predictive model for future vaccination and the effect size of each independent variable were estimated. As statistical analysis software, SAS 9.4 (SAS Institute Inc., Cary, NC, USA) was used, and because the sample size was not large, the significance level was set at 10%, and when the p-value was less than 0.10, it was interpreted as statistically significant. In the simple logistic regression analysis, the reason why they answered that they would not be vaccinated every year was that they answered 'to prevent infection of family and hospital guests' rather than 'to prevent my infection' as the reason for the vaccination. It was 11.0 times higher and 3.67 times higher in the case of 'for the formation of collective immunity of the local community and the country'. The adverse reactions experienced after the 1st and 2nd vaccination were 8.42 times higher in those who did not experience pain at the injection site than those who did not, 4.00 times higher in those who experienced swelling or redness, and 5.69 times higher in those who experienced joint pain. There was a 5.57 times higher rate of absenteeism annually than those who did not. In addition, the more anxious they felt about vaccination, the more likely they were to not get the vaccine every year by 2.94 times.

• Korean Journal of Environment and Ecology
• /
• v.37 no.4
• /
• pp.289-301
• /
• 2023

Forests within watersheds are essential in maintaining ecosystems and are the central infrastructure for constructing an ecological network system. However, due to indiscriminate development projects carried out over past decades, forest fragmentation and land use changes have accelerated, and their original functions have been lost. Since a forest's structural pattern directly impacts ecological processes and functions in understanding forest ecosystems, identifying and analyzing change patterns is essential. Therefore, this study analyzed structural changes in the forest landscape according to the time-series land cover changes using the FRAGSTATS model for the dam watershed of the Geum River upstream. Land cover changes in the dam watershed of the Geum River upstream through land cover change detection showed an increase of 33.12 square kilometers (0.62%) of forests and 67.26 square kilometers (1.26%) of urbanized dry areas and a decrease of 148.25 square kilometers (2.79%) in agricultural areas from the 1980s to the 2010s. The results of no-sampling forest landscape analysis within the watershed indicated landscape percentage (PLAND), area-weighted proximity index (CONTIG_AM), average central area (CORE_MN), and adjacency index (PLADJ) increased, and the number of patches (NP), landscape shape index (LSI), and cohesion index (COHESION) decreased. Identification of structural change patterns through a moving window analysis showed the forest landscape in Sangju City, Gyeongsangbuk Province, Boeun County in Chungcheongbuk Province, and Jinan Province in Jeollabuk Province was relatively well preserved, but fragmentation was ongoing at the border between Okcheon County in Chungcheongbuk Province, Yeongdong and Geumsan Counties in Chungcheongnam Province, and the forest landscape in areas adjacent to Muju and Jangsu Counties in Jeollabuk Province. The results indicate that it is necessary to establish afforestation projects for fragmented areas when preparing a future regional forest management strategy. This study derived areas where fragmentation of forest landscapes is expected and the results may be used as basic data for assessing the health of watershed forests and establishing management plans.

• Journal of Nutrition and Health
• /
• v.56 no.3
• /
• pp.300-314
• /
• 2023

Purpose: This study sought to predict the reasons for skipping breakfast by adolescents aged 13-18 years using the 7^th Korea National Health and Nutrition Examination Survey (KNHANES). Methods: The participants included 1,024 adolescents. The data were analyzed using a complex-sample t-test, the Rao Scott χ²-test, and the classification and regression tree (CART) algorithm for decision tree analysis with SPSS v. 27.0. The participants were divided into two groups, one regularly eating breakfast and the other skipping it. Results: A total of 579 and 445 study participants were found to be breakfast consumers and breakfast skippers respectively. Breakfast consumers were significantly younger than those who skipped breakfast. In addition, breakfast consumers had a significantly higher frequency of eating dinner, had been taught about nutrition, and had a lower frequency of eating out. The breakfast skippers did so to lose weight. Children who skipped breakfast consumed less energy, carbohydrates, proteins, fats, fiber, cholesterol, vitamin C, vitamin A, calcium, vitamin B1, vitamin B2, phosphorus, sodium, iron, potassium, and niacin than those who consumed breakfast. The best predictor of skipping breakfast was identifying adolescents who sought to control their weight by not eating meals. Other participants who had low and middle-low household incomes, ate dinner 3-4 times a week, were more than 14.5 years old, and ate out once a day showed a higher frequency of skipping breakfast. Conclusion: Based on these results, nutrition education targeted at losing weight correctly and emphasizing the importance of breakfast, especially for adolescents, is required. Moreover, nutrition educators should consider designing and implementing specific action plans to encourage adolescents to improve their breakfast-eating practices by also eating dinner regularly and reducing eating out.

• Korean Journal of Culture and Social Issue
• /
• v.25 no.2
• /
• pp.101-118
• /
• 2019

Alexithymia refers to a psychological deficit of identifying and describing one's feelings. It has benn reported that the level of alexithymia of East-Asians is generally higher than that of Western Europeans. Recently one research conducted in U.S. suggested that the interdependent self-construal from East-Asians' collectivism culture might be a cause of this cross-cultural difference. In the current study, we examined the relationship between the level of independent and interdependent self-construal of Korean college students and their level of alexithymia, as well as their ambivalence over emotional expressiveness and emotion suppression. The correlation analysis shows that the Korean students' alexithymia level does not correlate with their level of interdependent self-construal, but negatively correlates with their level of independent self-construal. Moreover, it is also correlated with the level of ambivalence over emotional expressiveness(AEE) and emotion suppression(ES). Thus, we setup a double-mediation model between the deficiency of independent self-construal and alexithymia via AEE and ES, and estimate mediation effects using Hayes and Preacher(2014)s' Process analysis. The results show that the deficiency of independent self-construal has a direct effect as well as indirect effects of AEE and ES on the alexithymia level. Further analysis on the indirect effects reveals that the mediation effect of AEE and the double mediation effect of ES via AEE are significant, but the mediation effect of ES is not significant. Current results imply that the interdependent self-construal from the traditional collectivistic culture may not cause Korean college students' problems on the emotional expression, but the relatively lower independent self-construal may cause them. The deficiency of independent self-constural may raise up the level of self-defensive ambivalence over emotional expressiveness and suppress emotional expression by themselves, which can result in alexithymia.