• International Journal of Highway Engineering
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• v.11 no.3
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• pp.13-21
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• 2009

The traveler's travel pattern has significantly changed due to the social and economic changes. The travel time among the traveler's pattern is the limited resource. The travelers are trying to maximize the utility of travel with the least travel cost. So, the travelers travel with their own travel time budget in mind, which they can pay or choose to pay for the optimal maximization of the utility of the individuals. This research is to group and extract the specific factors which affect the travel time budget by utilizing the CART analysis method, which enables the analysis of traveler's characteristics and their interrelationship based on the data collected from "2002 Household Travel Practice Research" and then try to derive a model for estimating the traveler’s travel time budget. The result of CART analysis shows that the factors which affect the travel time budget include the traveler's age, size of house, type of house, type of employment, job and relation to the head of household. Considering the affecting factors derived, I developed an estimation model. From that model, we found that the age, size of house and type of house were positively (+) related to the travel time budget while the homeworking people who have less travel frequency as a type of employment were negatively (-) related to it. In particular, from the point of type of job, the housewives, children not yet old enough to attend schools and people who are working in the agricultural, or marine product industries were found to have the negative (-) value while the people who have the administrative, office, management jobs were found to have the positive (+) value.

• Journal of Science Education
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• v.34 no.1
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• pp.140-154
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• 2010

The core of subject matter education is determined by the choice of subject matter taught to students and by the organization of content according to educational objectives. The purpose of this research is to suggest ways to improve the present content of science education so as to prepare students and schools for a radically different future. We deduced the main issues the solution of which could lead to significant improvements in the contents of science education by analyzing previous studies and investigating the changes in content that were effected during curriculum revisions in the past. The main issues thus revealed through this study are as follows: the essence of the contents of subject matters in science education, the social and cultural background of change in the science curriculum, the rational steps on the way to choosing contents as part of the science curriculum, the processes of choosing the main contents of each subject, the international comparative study of contents, the updating of contents for the benefit of future society, and the reorganization of subject contents. In order to find a concrete improvement on the issues deduced, we organized an expert group. Then, we proceeded to collect and analyze the experts' opinions. A survey was administered to 19 science education experts working with universities and colleges of education. We examined their degree of agreement on the issues and problems, and on the steps that may be taken to us the improvements on these issues. we suggested that: collecting opinion and reaching an agreement on the essence of the contents of the subject matters in science education, the necessity to choose core contents within the scientific domain, developing a structure map in order to integrate and connect various subject domains, presenting explicitly the objective of inquiry by grades, moving toward integrating science contents, diversifying the construction of science textbooks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.279-285
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• 2017

The study on 'support for V2V(Vehicle to Vehicle) services based on LTE sidelink' has been carried out in 3GPP RAN working group. The conventional LTE sidelink technology is not adequate for high speed V2V communications because the conventional DM-RS(Demodulation Reference signal) structure is developed for pedestrian environment. While the typical speed of pedestrian environment is 3km/h, that of V2V communications is 120 km/h and the information on channel estimation is not sufficient with legacy DM-RS structure. In this paper, improved DM-RS structures for V2V communications that have rapid channel variation are introduced and the performance of channel estimation accuracy is analyzed. Simulation results show that the performance improvement of channel estimation can be achieved based on extended sub-carrier spacing structure resulted from reduced inter-carrier interference. However, the extended sub-carrier spacing requires the longer cyclic prefix and higher overhead. As a results of considerations on DM-RS modification, the sub-carrier spacing is maintained and the high density of DM-RS is applied for V2V communications.

• Safety and Health at Work
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• v.11 no.1
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• pp.33-40
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• 2020

Background: Exploratory study to investigate whether co-exposure to physical wrist stressors and chemicals is associated with carpal tunnel syndrome (CTS) in French male farmers and agricultural workers. Methods: Cross-sectional study of 711 men aged 30-65 years and working as either farmers or agricultural workers in 2009-2010 within a cohort covered by the French Agricultural Workers' and Farmers' Mutual Benefit Fund. CTS and exposure to physical wrist stressors and chemicals were assessed using a self-administered questionnaire. Associations between CTS and personal/medical factors, exposure to physical wrist stressors, exposure to chemicals, and co-exposure to physical wrist stressors and chemicals were studied using multivariate logistic regression models. Results: Forty-four men {5.6% [95% confidence interval (CI) 4.0-7.7]} reported that they had suffered from unilateral/bilateral CTS during the last 12 months. CTS was associated with age, current smoking [odds ratio (OR) = 2.1 (1.0-4.5)], and exposure to physical wrist stressors [OR = 2.6 (1.1-5.9)]. An association was found between CTS and co-exposure to physical wrist stressors and chemicals [OR = 3.3 (0.8-14.3), p = 0.044] in comparison with the no-exposure group. Conclusions: This exploratory study shows an association of CTS with exposure to biomechanical wrist stressors in male farmers and agricultural workers and suggests an association of CTS with co-exposure to physical wrist stressors and chemicals. Owing to the limitations of the study, this result must be confirmed by a prospective study with objective assessments of the outcome and exposure before drawing conclusions on the possible synergistic effects of mechanical stressors and chemicals on the impairment of the median nerve.

• Proceedings of the Population Association of Korea Conference
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• 2006.12a
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• pp.59-87
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• 2006

This paper explores the effects of the 1997 economic crisis on the pattern of socioeconomic differentials in fertility. Based on analysis of data from the 2003 Korea National Fertility Survey, this study focuses on recent changes in the level of fertility according to socioeconomic status of the couple including educational level, occupation, working status, income, etc. Results reveal that the level of fertility of those with the highest education, most prestigious occupation, and employer status are higher than those of the next group in the socioeconomic hierarchy. These findings imply that the straight line inverse pattern of socioeconomic differentials in CEB yielded to a reversed J-shaped curve. However, recent differentials of fertility after the economic crisis were found to contrast with the pattern above. Decrease in fertility has been most drastic among those with a high level of fertility, and relatively slow for those with a low level of fertility. The level of recent fertility turns out to be highest among those with upper-middle socioeconomic status, followed by those with the highest socioeconomic status and those with the lowest status. Policy implications and some comments on current population policies of the Korean government are also presented in this paper.

• Journal of Digital Convergence
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• v.13 no.7
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• pp.33-45
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• 2015

Present study aims to describe who are the non-regular female workers in South Korea. The dominant form of employment of Korean female non-regular workers is characterized by instable contract, low wage, long-time work and exclusion from the state and occupational welfare. Also, non-regular female workers are not homeogenous but there are various groups of women among female non-regular workers including young part-time workers, high educational middle class contract professionals, particular contract workers such as home-schooling teachers. However, it would worth noting that over 40s, low-educational, low income, breadwinning women who are working in sales, service, and simple handy job are most likely to become non-regular female workers in South Korea. Those women are the major group among non-regular female workers. The public assistance (in cash) for non-regular workers are necessarily needed for them at this point in South Korea.

• Journal of Korean Physical Therapy Science
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• v.18 no.4
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• pp.31-46
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• 2011

The purpose of this survey was to give data and information about type and needs of Home Physical Therapy, Visiting Physical Therapy and School Physical Therapy for physical and nurse. The subjects were 154(99 physical therapists and 55 nurses) who were working at geriatric rehabilitation hospitals and children hospitals. The period of questionary collection was from the 15 of August to the 15th of September 2011. And data was analysis from 99 articles such as journals related to physical therapy, and searched with keyword 'home and visiting physical therapy' by web site and Korea National Assembly Library from 1991 to 2011. The data was analysis with percentage, mean, standard deviation and ANOVA by SPSS PC 12.0. The results were as follows; 1. The definition of 'Home Physical Therapy' has been community based on physical therapy service for the patient who had diagnosis by medical doctor, has been based on medical law. The definition of 'Visiting Physical Therapy' has been community based on physical therapy service at home for the patient who had diagnosis by medical doctor, for the national basic living security, and senior citizen over 65 years who lives alone, has been based on law for community health and law of long term health insurance. The definition of 'School Physical Therapy' has been school based on physical therapy service at school after class for the disabled children who are studying at school, has been based on special education law article 28. 2. As for the knowledge of the Home and Visiting and School Physical Therapy, both groups PT and nurse were 'I do not know'125(81.3%) of the difference the concept of 3 definitions, so it means to need education and information about the different concept of three physical therapy. As for the needs of home and visiting physical therapy, both groups of PT and Nurse were 'needs' 151(98.1%). Physical therapist showed of 'Needs' on visiting physical therapy 35(35.4%), home physical therapy 32(32.3%), and schole physical therapy 32(32.3%). Nurse showed of 'Needs' on home physical therapy 23(41.8%). visiting physical therapy 19(34.5%), school physical therapy 13(23.6%). Therefore it is necessary to have home and visiting physical therapy as for the elderly and disabled person. 3. As for the qualification of Home and Visiting physical therapist, both PT and nurse groups showed as follows; take post graduation education program for home and visiting therapy after became PT : home physical therapist 108(70.1%), visiting physical therapist 106(68.8%). So it means education center or university can be developed post graduation program for home and visiting physical therapist. 4. As for the 'Needs' of school physical therapy, both groups of PT and nurse showed as follows; 'Needs' 142(92.2%), 'Needs superviser education program' 148(96.1%), in PT group showed 'I will participate of education program' 92(92.9%). 5. As for the present states of research papers or report of home, visiting, and school physical therapy was as follows; the 103 papers for 8 fields about' the needs of home and visiting physical therapy' from 1991 to 2011, the 13 papers for 2 fields about school physical therapy from 2001 to 2011, so total papers were 114 articles.

• Journal of Distribution Science
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• v.12 no.6
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• pp.41-48
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• 2014

Purpose - This study aims to investigate a solution to reduce the negative reactions arising from the performance of duties or the job distress of workers in the service industry, because human resource statistics regarding workers in the service sector have been unreported, while concerns regarding exposure to emotional exertion and poor working conditions have been continuously increasing. Research design, data, and methodology - This study specifically focused on workers in highway service areas. It differs from previous studies because it involves the perspective of the person-organization fit and regards workers' cognition of leaders through the psychological distance toward the leader and the contact frequency between workers and leaders within the framework of the leader-individual fit. Moreover, this study highlights the role of the self-leadership of workers as an important factor that becomes manifested in the individual-level fit to the organization. Hence, this study investigates whether the positive role of the above factors, in turn, could reduce job distress. Workers from highway service areas in Gyeonggi-do province provided data; 141 valid questionnaires are collected. SPSS 19.0 and AMOS 19.0 were used to test the reliability and validity of constructs. Simple regression, multiple regression, and 3 step mediation tests were used to test the hypotheses after the correlation tests. Results - Results indicated that leader-member contact frequency and psychological distance have negative effects on job distress but positive effects on self-leadership. A mediation test revealed that self-leadership, in the relationships between contact frequency and job distress and between psychological distance and job distress, resulted in partial mediation and full mediation, respectively. Conclusions - The result can be understood through two different possible explanations. First, service area workers generally possess a positive perspective toward their leaders. This can be interpreted to mean that increased contact frequency and psychological distance would be considered as supports from the leader, rather than intrusive controls or management schemes. Therefore, the management in highway service areas should invest efforts in increasing contact frequency as well as maximizing psychological similarities by adopting the viewpoints of workers in terms of moral and ethical management, to reduce the workers' job distress. The results relating to self-leadership also indicate that increased contact frequency must be accompanied by intentions for the effective promotion of workers' self-leadership. It also signifies the necessity of a strategic approach by leaders to induce workers to perceive "in-group"ness as suggested both by the similarity-attraction theory and by the social identity theory. In addition, the results of the mediation test of self-leadership indicate that because workers' self-leadership activates upon increased contact frequency by the leader, it should not be a means of control and should not be utilized only from the perspective of management. It is also suggested that strategies such as transfer of authority could have a positive effect in promoting the expansion of self-influence from workers.

• Restorative Dentistry and Endodontics
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• v.31 no.5
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• pp.371-377
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• 2006

The purposes of this study were to assess the accuracy of measurements in pre-enlarged canals with small instruments and to compare the accuracies, in enlarged canal, with small size instruments and instruments that match the actual canal diameter using Root ZX, Bingo1020, SmarPex, and e-Magic Finder. Ten extracted teeth were embedded in an alginate model made for testing apex locators. A size 10 file was placed into the root canal until the tip of the file reached the plane of the major diameter of the foramen under a dental operating microscope at the 25 x magnification. The measurement was done with digital caliper and defined as actual length. Electronic length measurement with a size 10 file in pre-enlarged canal was done by reading the index indicating Apex of each device to gain a definite value After completion of canal enlargement to a size 45 file, each difference between actual length and electric measurement value with a size 10 and 40 files in enlarged canal was recorded as L10 and L40. The one-way ANOVA and Scheffe's multiple range tests were computed for analyze the differences among the four apex locators in the same group. The Student's t-test between L10 and L40 of each locator was done. The accuracies of electronic measurements were significantly different among the 4 devices. The file size made no difference on the accuracy of electronic measurement in enlarged canal with same device. The e-Magic Finder was the most accurate device among the 4 apex locators used in this study.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.316-324
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• 1996

This study was conducted by relative time study to identify the allowance time and basic work time, which is together composed of the total work time, in the wage composition and work process composition. This study was done for the case of a basic one person a group from thinning treatment for some conifer species such as Japanese red pine, Japanese larch, pitch pine and Korean pine. 1. In order to apply the Japanese allowance time of four species to the general conifer case, the maximum value of allowance time composition value among those of four species was selected. The results are as follows: delay time for person 1.8%, rest time 14.1%, delay time for machine 12.5% and wating time 0.4%. The some of ratios of adjustment allowance time is 28.8%. 2. Estimated wage basis time table, which can be used for wage table or process table, was prepared by adding up adjusted general allowance time and standard work time estimated by estimation equation for each species through the time study.