• Journal of the Korean Society for Railway
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• v.15 no.5
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• pp.517-523
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• 2012

Double Stack Train(DST) is being used variously around USA and Canada. The greatest advantage of the DST is mass transportation without extending the length of freight train and number of cars. So the DST system can be a kind of innovative train to increase the competitiveness of rail logistic business. As the domestic rail logistic increase, for enhancement of environment friendly green transportation amount, the DST needs more for efficiency. In this study, as the alternative way to introduce the DST to the Kyungbu Line, it's investigated the extensibility of rail freight with the relation of rail fare discount and examined the necessity of pilot business to the Kyungjeon Line which was expected comparatively lower cost. If the DST system is introduced to the Kyungjeon Line, the cost of mass transportation can be much lower and then the comparativeness of rail transportation will be increased, therefore logistic companies can have some margin additionally. In the result of survey to the related companies, if rail transportation fare is 37.7 % cheaper than current road transportation fare, the modal shift can be transferred by maximum 100%.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1498-1508
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• 2009

Recently, the expansion of roads are necessary because the population and vehicles have rapidly increased, but those are restricted because of the limited site. JES(Jointed Element Structure) method is the method of the new cross-structure, which is element-traction method which draws and excavates elements under the existing structure with high accuracy within a short time. Also JES(Jointed Element Structure) method has a facility of the economical execution, a small effect on the train-service during construction period and no limit of the crossing length under the trade In this study, the tractive force and settlement are compared with the upper element, side wall element and the lower element respectively in the section which the JES method is applied In the case of element located at left side wall, the tractive force measured by a guage is double or more than the tractive force calculated by a formula. It is expected that many boulder contented in the ground contrary to the site investigation data cause high tractive force. For comparison of the settlement, the settlement as excavating the upper element is the largest in all steps. It is expected that this is the same as the cause of high tractive force. Also in this study, the practical use of the JES method when some under pass structures are extended in the future is studied.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.2
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• pp.142-156
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• 2024

The transition to electric vehicles is a crucial step toward achieving carbon neutrality in the transportation sector. Adequate charging infrastructure at residential locations is essential. In South Korea, the predominant form of housing is multifamily dwellings, necessitating the provision of public charging stations for numerous residents. Although the government mandates the availability of charging facilities and designated parking areas for electric vehicles, it bases the supply of charging stations solely on the number of parking spaces. Slow chargers, mainly 3.5kW charging outlets and 7kW slow chargers, are commonly used. While the former is advantageous for installation and use, its slower charging speed necessitates the coexistence of both types of chargers. This study presents an optimization model that allocates chargers capable of meeting charging demands based on daily driving distances. Furthermore, using the metaheuristic algorithm Tabu Search, this model satisfies the optimization requirements and minimizes the costs associated with charger supply and usage. To conduct a case study, data from personal travel surveys were used to estimate the driving distances, and a hypothetical charging scenario and environment were set up to determine the optimal supply of 22 units of 3.5kW charging outlets for the charging demands of 100 BEVs.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.915-926
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• 2017

The subway is the transportation means most commonly used by the citizens of the metropolitan area along with the buses in the metropolitan area and major metropolitan municipalities. However, satisfaction with the signboards is low and the signboards need to be improved. In this study, we investigated the problem of guide signs of city hall and exchange area with L - shaped history structure for guide signs affecting route finding. As a result, it is necessary to confirm whether the moving distance is long and moving accurately to the desired destination due to the L - shaped historical structure in both the station and the alternate area. In both stations, the number of the guide signs, Problems such as installation position, height, other. In this study, the movement within the subway station is classified according to the space. The type of guide sign installation was defined, and the specific principles for guiding the movement route were proposed. This research is expected to be useful as an important basic data for the types and layout of subway stations.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.290-298
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• 2004

In children, change in lifestyles such as an increase in participation of physical activities has increased the chance of receiving an injury, harming the child and their parents. This study was carried out to give basic information of traumatic injuries to the upper anterior teeth which can be used in prevention of future complications that may arise. From June, 2002 to May, 2003, of the 8,799 children in their primary and mixed dentition visiting Department of Pediatric Dentistry, College of Dentistry, Yonsei University 955 upper anterior teeth(primary 543, permanent 412) of 487 children(male 316, female 171) with traumatic injures to the upper incisors were studied. The results were as follows: 1. Trauma to the primary teeth prevailed at the age of 1-3 and to the permanent teeth at the age of 7. The male to female ratio was 1.85:1. 2. Trauma to the upper incisors for both the primary and permanent teeth occurred in the afternoon. Primary teeth were injured most frequently in the home(44.1%) and the permanent teeth outdoors, in the street(17.5%). 3. Both the primary and permanent teeth were most injured by fall-down injuries(39.8%, 12.9%), and next were collisions(22.2%, 6.0%). For the primary teeth, high fall, traffic accident, violence and sports are next in order, and for the permanent teeth, violence, sorts, traffic accidents were next. 4. Average number of 1.6 primary teeth and 2.8 permanent teeth were injured with the right central incisor most prevailing. 5. Crown fracture without pulpal exposure and subluxation injures were highest in frequency in both the primary and permanent teeth.

• Korean Journal of Community Nutrition
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• v.25 no.5
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• pp.416-429
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• 2020

Objectives: This study examined the personal, interpersonal and community factors related to food sufficiency and variety among Korean adults using data from the 2017 Community Health Survey. Methods: A total of 228,310 adults aged ≥ 19 years were classified into three groups: food sufficiency with variety, food sufficiency without variety and food insufficiency. Personal factors included sociodemographic characteristics, health behavior and health status. Interpersonal factors included social networking and social activities, and community factors included safety, natural environment, living environment, availability of public transportation and health care services. The association of food sufficiency and variety with interpersonal and community factors was assessed using multivariable logistic regression analyses. Results: Of the total sample, the food-sufficiency-without-variety group and food insufficiency group accounted for 31.5% and 3.2%, respectively. The sociodemographic factors associated with food insufficiency and non-variety were women, ≥ 65 years of age, with low education level, low household income, unemployed, single, and living in areas of small population sizes. There were significant differences in health behavior and health status, interpersonal and community factors among the three groups. Multivariable logistic regression analyses conducted after adjusting for confounding factors showed that lack of social networking and social activities and lower satisfaction derived from community environments were associated with the risk of food insufficiency and non-variety. Conclusions: Our results showed that interpersonal and community factors as well as personal factors were related to food sufficiency and variety. Therefore, public policies to help build social networks and participation in social activities, and improve community environment are needed together with food assistance to overcome the problems of food insufficiency and non-variety.

• Journal of agricultural medicine and community health
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• v.25 no.1
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• pp.133-147
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• 2000

To provide data for the improvement of primary health care through the study on the utilization rate of community health practitioner(CHP) post and its related factors toward some rural residents in Mooan County Chollanamdo, a questionnaire survey was made from 382 persons during August 1999. Comparison was made between persons at the seaside area under difficult transportation and persons at the railroad area under convenient transportation. The results are as follows: 1. For the last one year, 83.3% of seaside area residents and 67.0% of railroad area residents used CHP post. As the purpose of visit to CHP post at seaside area, 94.3% visited for medical care, 25.3% for chronic disease control and 22.2% for health counselling and 14.1% for chronic disease control. 2. By simple analysis, sex, age, marital status, educational level, residence area, distance from living village to CHP post, presence of chronic diseases, satisfaction with CHP and confidence on CHP were related significantly with the utilization of CHP post for the last one year. 3. By multiple logistic regression, statistically significant variables related with the utilization rate of CHP post for the last one year were analyzed as age, sex, residence area and distance from living village to CHP post.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.1-12
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• 2009

A new mix design procedure for cold in-place recycling using foamed asphalt (CIR-foam) has been developed for Iowa Department of Transportation. Some strengths and weaknesses of the new mix design parameters were considered and modified to improve the laboratory test procedure. Based on the critical mixture parameters identified, a new mix design procedure was developed and validated to establish the properties of the CIR-foam mixtures. As part of the validation effort to evaluate a new CIR-foam mix design procedure, dynamic moduli of CIR-foam mixtures made of seven different reclaimed asphalt pavement (RAP) materials collected throughout the state of Iowa were measured and their master curves were constructed. The main objectives of this study are to provide: 1) standardized testing procedure for measuring the dynamic modulus of CIR-foam mixtures using new simple performance testing (SPT) equipment; 2) analysis procedure for constructing the master curves for a wide range of RAP materials; and 3) impacts of RAP material characteristics on the dynamic modulus. Dynamic moduli were measured at three different temperatures and six different loading frequencies and they were consistent among different RAP sources. Master curves were then constructed for the CIR-foam mixtures using seven different RAP materials. Based upon the observation of the constructed master curves, dynamic moduli of CIR-foam mixtures were less sensitive to the loading frequencies than HMA mixtures. It can be concluded that at the low temperature, the dynamic modulus is affected by the amount of fines in the RAP materials whereas, at the high temperature, the dynamic modulus is influenced by the residual binder characteristics.

• Journal of Navigation and Port Research
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• v.43 no.4
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• pp.250-255
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• 2019

The objective of this study was to analyze the risk of collision accidents to the VTSOs (Vessel Traffic Service Operators) as small ferries and fishing boats are expanded for monitoring targets. The VTSOs was surveyed, the scale of the small vessels defined and the course of general cargo vessels and small vessels along the Busan VTS area investigated for three days. From calculating the risk with CoRI, patterns of increased or decreased risk due to course deviation were similar, and there was no significant difference between the maximum values and the minimum values. In addition, most VTSOs responded that the minimum time required was approximately three minutes to safely instruct in encounter situation, however, the collision risk with a small vessel is very rapidly changing within the three minutes, which is likely to increase the workload and decrease the concentration of the VTSOs. The objective of this study was to investigate the effect on VTSOs with respect to the expansion of small vessels as collision risk, it is expected that it will contribute to the establishment of a suitable scale for the target vessels for VTS through the analysis of each index of the CoRI model and various case studies.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.747-758
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• 2022

This study aimed to identify the factors that influence depression in stressed adults by age. Data were extracted from the 7th Korea National Health and Nutrition Examination Survey, covering 3,333 adults aged 20 to 59 years who were highly aware of stress. Linear regression analysis was performed using the IBM SPSS 25.0 program. The study found that in the case of people in their 20s, education level, health-related quality of life, obesity, weight change, smoking, and subjective body type were significant influencing factors, with an explanatory power of 60.3%. In the case of people in their 30s, gender, household income level, living with spouse, economic activity, health-related quality of life, food intake, obesity, alcohol consumption, smoking, and subjective health were significant influencing factors, with an explanatory power of 30.3%. For people in their 40s, household income level, living with spouse, economic activity, health-related quality of life, smoking, aerobic exercise, and subjective health were significant influencing factors, with an explanatory power of 34.4%. For people in their 50s, gender, education level, income, economic activity, health-related quality of life, protein intake, fat intake, high blood pressure, diabetes, weight control, aerobic exercise, subjective health, and subjective body type were significant influencing factors, with an explanatory power of 42.3%. Therefore, as it was found through this study that the factors affecting depression in stressed adults differ by age, it is necessary to establish an intervention strategy for each age when trying to lower depression in stressed adults.