• The Mathematical Education
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• v.60 no.4
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• pp.431-449
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• 2021

Elementary mathematics textbooks present contents for enhancing problem solving competency. Still, teachers find teaching problem solving to be challenging. To understand the supports textbooks are suggesting, this study examined tasks from the challenging/thinking and inquiry mathematics. We analyzed 288 mathematical activities based on an analytic framework from the 2015 revised mathematics curriculum. Then, we employed latent class analysis to classify 83 mathematical tasks as a new approach to categorize tasks. As a result, execution of the problem solving process was emphasized across grade levels but understanding of problems was varied by grade levels. In addition, higher grade levels had more opportunities to be engaged in collaborative problem solving and problem posing. We identified three task profiles: 'execution focus', 'collaborative-solution focus', 'multifaceted-solution focus'. In Grade 3, about 80% of tasks were categorized as the execution profile. The multifaceted-solution was about 40% in the thinking/challenging mathematics and the execution profile was about 70% in Inquiry mathematics. The implications for developing mathematics textbooks and designing mathematical tasks are discussed.

• Safety and Health at Work
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• v.14 no.1
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• pp.85-92
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• 2023

Background: Presenteeism is closely related to work performance, work quality and quantity, and productivity at work. According to the job demand-control-support model, job demand, job control, and support play important roles in presenteeism. The present study investigated job characteristics profiles based on the job demand-control-support model and identify the association between job characteristics profiles and presenteeism. Methods: This secondary data analysis used the Sixth Korean Working Condition Survey, a nationwide cross-sectional dataset. The study included 25,361 Korean wage workers employed in the workplace with two or more workers. Participants were classified into four job characteristics profiles based on the job demand-control-support model, using latent profile analysis, and logistic regression was performed to examine the association between study variables. Results: Overall, 11.0 % of study participants reported experience of presenteeism in the past 12 months. Age, sex, location, monthly income, shift work, work hours, health problems, and sleep disturbances were significantly associated with presenteeism. The rate of presenteeism was the highest in the passive isolate group. The passive collective, active collective, and low-stain collective groups had a 23.0%, 21.0%, and 29.0% lower likelihood of experiencing presenteeism, respectively, than the passive isolate group. Conclusions: The job demand-control-support profiles and the risk of presenteeism were significantly associated. The most significant group that lowered the experience of presenteeism was the low-strain collective group, which had a low level of demand and high levels of control and support. Therefore, we need a policy to reduce job demand and increase job control and support at the organizational and national levels.

• Communications of Mathematical Education
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• v.34 no.1
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• pp.17-39
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• 2020

The purpose of this study is to analyze the mathematical beliefs of students and teachers by Latent Class Analysis(LCA). This study surveyed 60 teachers about beliefs of 'nature of mathematics', 'mathematic teaching', 'mathematical ability' and also asked 1850 students about beliefs of 'school mathematics', 'mathematic problem solving', 'mathematic learning' and 'mathematical self-concept'. Also, this study classified each student and teacher into a class that are in a similar response, analyzed the belief systems and built a profile of the classes. As a result, teachers were classified into three types of belief classes about 'nature of mathematics' and two types of belief classes about 'teaching mathematics' and 'mathematical ability' respectively. Also, students were classfied into three types of belief classes about 'self concept' and two types of classes about 'School Mathematics', 'Mathematics Problem Solving' and 'Mathematics Learning' respectively. This study classified the mathematics belief systems in which students were categorized into 9 categories and teachers into 7 categories by LCA. The belief categories analyzed through these inductive observations were found to have statistical validity. The latent class analysis(LCA) used in this study is a new way of inductively categorizing the mathematical beliefs of teachers and students. The belief analysis method(LCA) used in this study may be the basis for statistically analyzing the relationship between teachers' and students' beliefs.

• 한국노년학
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• v.40 no.4
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• pp.691-706
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• 2020

This study aims to explore health behavior profiles and the association between the derived profiles and living arrangement among middle-aged and older adults. Using data from wave 6 (2016) of the Korean Longitudinal Study of Aging, latent profile analyses were applied to identify patterns of health behaviors and multinomial logistic regression models were conducted to predict profile membership using living arrangement (i.e., living alone, living with spouse only, living with family members) and sociodemographic characteristics. A sample of 7,048 respondents aged 55 and older were included in the study. Results revealed that Korean middle-aged and older adults can be grouped into four health behavior profiles: "High health-compromising" (4%), "Moderate health-compromising" (28%), "Low health-compromising" (65%), and "High physical activity" (3%). Also, living arrangement showed significant profile differences. Compared to the respondents living alone, those living with spouse only were more likely to belong to low and moderate levels of health-compromising behavior profiles than the "High physicial activity profile". Respondents living with family members were more likely to belong to the "High health-compromising profile" than the "High physical activity profile" compared to those living with spouse only. These findings indicate that living arrangement needs to be taken into consideration when developing health promoting programs and supports. Moreover, policy interventions suiting the needs of various sociodemographic subgroups are recommended.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.379-388
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• 2016

There are various system defects from weapons manufacturing due to the numerous production processes and various production environments. The first kind of defect is patent defects, which can be detected by visual inspection, functional testing, and existing quality control procedures during the manufacturing process. The second kind is latent defects, which cannot be detected though existing quality management approaches because of the complexity of the system and manufacturing process. To minimize the initial defect problems, environmental stress screening (ESS) is needed to detect the defects, remove them, and improve the product conditions based on the environmental stress conditions of temperature and vibration. We implemented a tool for quantitative ESS effectiveness analysis and profile design automation based on MIL-HDBK-344 and verified it using six scenarios with different temperature stress, vibration stress, and test designs.

• Journal of Digital Convergence
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• v.16 no.1
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• pp.439-452
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• 2018

This study aims to empirically structure the patterns of consumption and their effects on depression among the employed baby-boomers who were born in 1955 to in 1963. We used the 5th wave of Korea Retirement and Income Study(KReIS) in 2013 (n=2,585). The Latent Profile Analysis(LPA) estimated the empirical patterns of consumption and then a multiple regression analyzed the effect of consumption patterns on depression. The LPA results showed that the consumption patterns consist of four groups: Basic life-oriented class, Social life-oriented class, Home-based lifestyle class, and Advanced consumption-oriented class. The working baby boomers' depression was associated with their consumption patterns. Specifically, the social life-oriented class showed significantly lower depression than the basic life-oriented class and advanced consumption-oriented class. Other associates with higher levels of depression were found as lower education, having no spouse, lower self-rated health, higher levels of physical limitation, having a diagnosed disability, lower satisfaction with leisure activities, lower income, and lower subjective economic status in this study. Based on the results of this study, we propose the need for specialized financial intervention better for baby-boomers' retirement preparation in Korea.

• Journal of the Korean Society for information Management
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• v.40 no.4
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• pp.375-401
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• 2023

A school library is where students develop their skills to cope with future uncertainty and can utilize various information materials to build their capability and response abilities to changes. Teachers' perception is crucial as their guidance is essential for the student to use the school library. Most studies, however, focused on quantitative measurement of the importance of the teachers' perception as an external environment, and there is a lack of specific categorization of different types of perceptions on the role of the school library. This study aims to examine types of perceptions about the school library among elementary school teachers. To do so, this study used Latent Profile Analysis (LPA), a person-centered approach, to identify teachers' complex perceptions about the role and importance of the school library, which were difficult to review in previous studies, and the teachers' most representative types of perceptions. Based on the findings from the above, this study is meaningful in proposing customized measures to operate and promote the school library depending on teachers' perceptions.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.2
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• pp.107-114
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• 2017

Results of the analysis have revealed that the students were basically divided into three groups depending on goodness-of-fit index and latent class division factor. Type 1 was regarded as a low dependence group (50.1%) with all low indexes while Type 2 was classified as a high dependence group (10.7%) with all high indexes. As for Type 3, it was titled intermediate dependence group (39.2%) for the indexes showed a low-to-moderate movement. A multinomial logistic regression analysis was carried out to forecast smart phone dependence characteristics and as a consequence, when the high dependence group was compared to the intermediate dependence group, as self-esteem and peer attachment increased and deceased respectively, a chance of one being classified into the intermediate dependence group rose. In an investigation to compare the high dependence group with the low dependence group, it was confirmed that the greater the self-esteem, the shorter the peer socializing time, the lower the neglect degree and the lower the peer attachment, a chance for one belonging to the low dependence group increased. This study also offered implications, limits and directions in follow-up research.

• The Journal of the Korea Contents Association
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• v.22 no.10
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• pp.733-741
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• 2022

Among the various evidence found in maritime crimes, fingerprints and DNA are very important in that they can identify a suspect. In this study, 5 types of non-porous surfaces (plastic, stainless, glass, ceramic, FRP), which are often found as evidence in the actual marine environment, were selected, and latent and blood fingerprints were passed down and immersed at the Donghae Maritime Police Station's exclusive pier for about 7 days. After that, DNA extraction, quantification, and STR profile were analyzed after fingerprint developing CA fumming method and 4 powder methods (Swedish black powder, Concentrated black powder, Supranano red powder, Dazzle orange powder). Among the fingerprint developing methods, when Supranano red powder was applied, a relatively high amount of DNA was found. As a result of STR profile analysis, an average of 16.8 to 9 loci were secured, and all 20 were confirmed in glass and ceramic materials. As a result of the study, it was possible to secure the STR profile by extracting and quantifying DNA after applying the fingerprint developing method to virtual evidence immersed for about 7 days, and further research is needed to secure the STR profile by analyzing DNA after applying various fingerprint developing methods such as VMD and SPR.

• Journal of Korea Multimedia Society
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• v.20 no.1
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• pp.66-73
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• 2017

Due to the recent rapid changes in society and wide spread of information devices, diverse digital information is utilized in a variety of economic and social analysis. Information related to the crime statistics by type of crime has been used as a major factor in crime. However, statistical analysis using only the structured data has the difficulty in the investigation by providing limited information to investigators and users. In this paper, structured data and unstructured data are analyzed by applying Korean Natural Language Processing (Ko-NLP) and the Latent Semantic Analysis (LSA) technique. It will provide a crime profile optimum system that can be applied to the crime profiling system or statistical analysis.