• East Asian mathematical journal
• /
• v.5 no.2
• /
• pp.233-241
• /
• 1989

• Journal of Korean Society of Transportation
• /
• v.24 no.1 s.87
• /
• pp.59-72
• /
• 2006

In spite of continuous implementation of the transportation demand management (TDM), the profuse use of car at the peak-time has caused chronic traffic congestion in the Seoul downtown area. This study makes a comparative analysis on the effectiveness of commuting cost subsidy system for public transit user with other policy instruments such as an increment in fuel tax and park cost. This study not only follows standard guidelines of stated preference methodology to guarantee objectivity, but also uses sample enumeration method and non-Parametric bootstrapping method to secure reliability of empirical results. As a result of empirical studies, the conversion effect of car to public transit is superior to other two Policy instruments. Also. an increment in fuel tax and park cost is income-regressive from the equity aspect in a wage bracket, but commuting cost subsidy system for Public transit user is Income-progressive As a fundamental research on commuting cost subsidy system for public transit user, this study is likely to Provide Policy-makers with quantitative information useful in establishing Public transport Policy to Promote the use of the public transit.

• The Korean Journal of Community Living Science
• /
• v.15 no.1
• /
• pp.35-47
• /
• 2004

This study investigated the health and eating habits of college students who commute long distances to and from their schools. Among ninety-eight commuters, 61.2% were females while 38.8% were males. The mean round-trip commuting time was 4.60 hours and the mean number of days of commuting was 3.68. The proportion of underweight females (26.7%) was significantly greater than that of underweight males (5.3%). Conversely, the proportion of overweight males was 34.2% while only 1.6% of the females were overweight, and the difference was statistically significant. The mean number of health-related problems was 1.47 for males and 1.90 for females. Commuting affected the eating habits (90.8%) and health status more noticeably among females. Physical discomfort such as fatigue, stomach discomfort, constipation, weight change, and insomnia appeared after commuting. Irregular meal times, skipping breakfast, frequent overeating and insufficient time to eat were the most prevalent problems indicated. The scores for dietary attitude and eating habits were 20.1/30 and 27.6145, for males and females respectively. Although self-perceived nutrition knowledge was significantly related to dietary attitude and satisfaction with meals, a correlation was not found between self-perceived nutrition knowledge or dietary attitude and the eating habits score. The more concerned the parents were about student's eating habits, the higher the score relating to eating habits. The parents' concerns about students' meals and the food expenses were significantly correlated, but no correlation was found between the food expenses and the eating habits score. Consistent parental concern and encouraging students to maintain good eating habits are recommended. University administrators should also be aware of the needs of commuters and provide a proper and adequate food-related environment for the students.

• Journal of Environmental Health Sciences
• /
• v.35 no.6
• /
• pp.447-453
• /
• 2009

Cycling has been lately recommended as an alternative commuting mode because it is believed to be good for health and the environment. However, the exposure to environmental pollutants, such as fine particulates, could be a potential problem for cycling in urban environments. In this study, we compared commuters' $PM_{10}$ exposure using the different transportation modes of bicycle and bus. When a bicycle was used as a commuting mode, the additional $PM_{10}$ exposure due to transportation was about 3.5 times higher than that when using a bus. The difference of additional $PM_{10}$ exposures by cycling and bus was statistically significant (p<0.01). The $PM_{10}$ exposure during cycling was significantly correlated with atmospheric $PM_{10}$ concentration (r=0.98, p<0.01) and its correlation coefficient was higher than that of bus (r=0.55, p<0.05). The results of this study demonstrated that the main reasons of higher $PM_{10}$ exposure when using the bicycle as the mode of transport were its vicinity to road traffic and routes that were unavoidably close to road traffic. Bicycle commuting along the road side may not be good for health. Exclusive bicycle lanes away from road traffic are recommended.

• Journal of Korean Dental Hygiene Science
• /
• v.1 no.2
• /
• pp.21-39
• /
• 2018

The purpose of this study was to examine the learning competencies of students at a college from September 1 to November 30, 2017, in an effort to provide some information on how to foster learning competencies in college years, which lay the foundation for work and social lives. 1. The learning competencies of the subjects consisted of academic vision, student identity, cognitive regulation, emotional regulation, learning management and creating learning environments. Out of five points, they scored the highest in academic vision and student identity with 3.34, followed by learning management with 3.20, creating learning environments with 3.18, emotional regulation with 3.16 and cognitive regulation with 3.14. 2. There were statistically significant differences in academic vision according to age, the area of major, the academic credential of their fathers, commuting time, military service experience and career plans. 3. There were statistically significant differences in student identity and cognitive regulation according to gender, age, the area of major, the academic credential of their fathers, commuting time, military service experience and career plans. 4. There were statistically significant differences in emotional regulation according to age, the area of major, the academic credential of their fathers, commuting time, career plans and daily mean study hours. 5. There were statistically significant differences in learning management according to gender, age, the area of major, grade point average, the academic credential of their fathers, career plans and daily mean study hours. 6. There were statistically significant differences in creating learning environments according to gender, age, the area of major, the academic credential of fathers, commuting time, career plans and daily mean study hours. As they were poorest at the cognitive regulation area among the areas of learning competencies, self-directed learning programs that deal with how to study, learning process, how to take notes and arrange them, how to link different pieces of acquired knowledge and how to map out study plans should be developed to give support to students.

• Journal of Convergence for Information Technology
• /
• v.7 no.3
• /
• pp.65-71
• /
• 2017

The quantum logic was introduced by G. Birkhoff and 1. von Neumann in order to study projections of a Hilbert space for a formulation of quantum mechanics, and Husimi proposed orthomodular law and orthomodular lattices to complement the quantum logic. Abott introduced orthoimplication algebras and its properties to investigate an implication of orthomodular lattice. The commuting relation is an important property on orthomodular lattice which is related with the distributive law and the modular law, etc. In this paper, we define a binary operation on orthoimplication algebra and the greatest lower bound by using this operation and research some properties of this operation. Also we define a homomorphism and characterize the commuting relation of orthoimplication algebra by the homomorphism.

• Communications of the Korean Mathematical Society
• /
• v.28 no.4
• /
• pp.643-647
• /
• 2013

Let G be a group and let $p$ be a prime number. If the set $\mathcal{A}(G)$ of all commuting automorphisms of G forms a subgroup of Aut(G), then G is called $\mathcal{A}(G)$-group. In this paper we show that any $p$-group with cyclic maximal subgroup is an $\mathcal{A}(G)$-group. We also find the structure of the group $\mathcal{A}(G)$ and we show that $\mathcal{A}(G)=Aut_c(G)$. Moreover, we prove that for any prime $p$ and all integers $n{\geq}3$, there exists a non-abelian $\mathcal{A}(G)$-group of order $p^n$ in which $\mathcal{A}(G)=Aut_c(G)$. If $p$ > 2, then $\mathcal{A}(G)={\cong}\mathbb{Z}_p{\times}\mathbb{Z}_{p^{n-2}}$ and if $p=2$, then $\mathcal{A}(G)={\cong}\mathbb{Z}_2{\times}\mathbb{Z}_2{\times}\mathbb{Z}_{2^{n-3}}$ or $\mathbb{Z}_2{\times}\mathbb{Z}_2$.

• Journal of Korean Society of Transportation
• /
• v.29 no.4
• /
• pp.29-41
• /
• 2011

This study investigates the factor that influences commuting time to work when individuals allocate their time for different types of activities. The commuting time is an important indicator for an individual to determine the residence and choose the means of transportation. The analysis uses the data collected from people who live in Seoul metropolitan area including Seoul, Incheon and Gyeonggi Province, and commute to work and making the simple linkage travel (home-work-home) within the area. For the analysis, the Cox hazard proportional methodology was adopted. The method is known to be well applied without assuming any distribution in case of the dependent variable being continuous. For the covariate, the interaction effect between the space variable of the work place and the variable of transportation has been also included in the model. The commuting time to work has been estimated for both 1) the whole metropolitan area and 2) the separate regions i.e., Seoul, Incheon and Gyeonggi-Do. The result reveals that characteristic variables related to individual, household and travel properties influence the mode of transportation and the time allocated for commuting to work (p<0.01). This study also demonstrates the usefulness of the Cox hazard proportional model. The data used in this study is the actual household travel data surveyed in 2006 in the metropolitan area, and analyzing the survey data in 2010 is currently in progress. Comparison of the two survey data sets seeking any behavioral change is suggested for the future study.

• Journal of the Korean Geographical Society
• /
• v.49 no.3
• /
• pp.390-404
• /
• 2014

This study analysed the job-housing balance using the number of employees and workers data, and investigated the relationship between job-housing ratio and commuting trip in the Seoul metropolitan area. Between 2005-2010, in the central business district which functioned as urban center, the number of employees were reduced and population growth slowed. Meanwhile, the suburbanization of employment and population has advanced as the employment and population moved from Seoul to Gyeonggi-do. As the increasement of workers compared to the employees became prominent, the excess workers increased significantly. The size of excess workers acted as a factor which reduced the job-housing ratio. Job-housing imbalance worsened in Gyeonggi-do especially. While in many regions, job-housing imbalance improved in clerical, sales, and professional job sectors, but in some regions, the job-housing imbalance worsened in simple labor job and service job sectors. The number of jobs which job-housing imbalance was eased increased in the employment center. The more the job-housing ratio is high, the lower the degree of self-sufficiency of commuting trip and the proportion of internal commuters. In business centers where the number of employees exceed the number of workers, the job-housing ratio and the proportion of commuting trips coming from other regions showed decreasing trend together. The results bear important implications for regional labour market plans considering the spatial mismatch between jobs and housing.

• Journal of Family Resource Management and Policy Review
• /
• v.27 no.1
• /
• pp.53-65
• /
• 2023

This study focused on Japanese families engaging in childrearing to discover changes in their daily lives, such as in the role division between husband and wife and hours spent on housework and childcare, caused by the unexpected crisis of COVID-19. An empirical analysis attempted to determine whether changes in the working environment, such as working and commuting hours, affected the role division between husband and wife, as well as housework and childcare hours spent. The data analyzed were extracted from the 2021 "3rd Survey on Changes in Lifestyle Awareness and Behavior Due to the Impact of COVID-19" conducted by the Japanese Cabinet Office. A total of 983 couples aged 20 or older, living with their spouse, having at least one child under the age of 18, and both employed were selected. The analysis results were as follows: First, the division of roles between husband and wife changed in the direction of increasing the husband's role in housework and childrearing. Second, the decrease in working and commuting hours increased the husband's role. Third, housework and childcare hours were more clearly related to changes in the working environments of husbands and wives than to changes in role division between husband and wife. In conclusion, changes in men's working and commuting hours had a greater impact on role division, as well as housework and childrearing hours in the family, than changes in women's working and commuting hours. In the future, an analysis that considers labor market factors is necessary.