• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.3
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• pp.277-285
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• 2016

Objectives: This study was performed in order to evaluate whether 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) could be detected among residents living near Camp Caroll in Waegwan and whether serum concentrations of dioxins, including 2,3,7,8-TCDD, and organochlorine pesticides (OCPs) are associated with length of residence. Methods: Study subjects totaled 113 (for dioxins) and 190 (for OCPs) adults who were selected from participants in a medical investigation. Serum concentrations of dioxins and OCPs were measured using HRGC/HRMS. Information on length of residence was obtained through questionnaires. Results: 2,3,7,8-TCDD was not detected in serum among all subjects. When length of residence was classified as a categorical variable, after adjusting for confounding variables, only residents living in Waegwan for 40 years or longer tended to have high total TEQ values and 2,3,4,7,8-PeCDF with marginal significances. There was no dose-response relation between length of residence and serum concentrations of these chemicals. In multiple regression models with continuous values of the length of residence, total TEQ value and 1,2,3,4,6,7,8-HpCDF were positively associated with length of residence. However, they explained about 3-5% of total variations of serum concentrations of these compounds, while age, consumption of fatty fish, body mass index, alcohol drinking, and cigarette smoking were main variables affecting serum concentrations of dioxins or OCPs. Conclusions: In the current study, high concentrations of certain compounds were mainly observed among persons who lived in Waegwan for at least for 40 years without a dose-response relation. Therefore, it seems difficult to conclude that length of residence meaningfully contributed to the current serum concentrations of dioxins or OCPs among residents in Waegwan. However, considering the half-life of 2,3,7,8-TCDD and indirect exposure routes, the limitations of the current study design should be considered in the interpretation of the study findings.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.575-583
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• 2017

This paper describes the design and evaluation of a driving mode decision algorithm for automated driving for merge situations on highways. For the development of a highly automated driving control algorithm for merge situations, the driving mode decision is crucial for merging appropriately. There are two driving modes: lane keeping and lane changing (merging). The merge mode decision is determined based on the state of the surrounding vehicles and the remaining length of the merge lane. In the merge mode decision algorithm, merge possibility and the desired merge position are decided to change the lane safely and quickly. A safety driving envelope is defined based on the desired driving mode using the information on the surrounding vehicles' behaviors. To obtain the desired steering angle and longitudinal acceleration for maintaining the subject vehicle in the safe driving envelope, a motion planning controller is designed using model predictive control (MPC), with constraints that are decided considering the vehicle dynamics, safe driving envelope, and actuator limit. The proposed control algorithm has been evaluated via computer simulation studies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1993-1999
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• 2013

Steel composite structures have been studied in various areas such as bridges, high rise buildings, and wind towers. They show excellent structural performance through overcoming of the weaknesses of steel and concrete. Although various methods were already developed to achieve full composite behavior between steel and concrete in flexural members, the number of studies regarding composite columns is quite limited. If slip occurs between concrete and steel under external loads, the performance of the composite column would be reduced significantly. Connection methods ensuring full composite action between steel and concrete must be suggested. This paper investigated about structural behavior of shear studs through a series of experimental tests. Extensive parameters were also performed to understand the effects of the diameter of stud, space of stud and height of concrete. The present study provides fundamental bases for further development of design method of shear studs in composite columns.

• International Journal of Highway Engineering
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• v.12 no.2
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• pp.33-41
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• 2010

It is stated in the highway geometric design guide that expressway interchange types should be selected considering a set of input variables including travel demand, topography, construction cost and interchange spacing. However, this selection method has a problem of providing different interchange types even for the same input variables depending upon different applications of engineers discretion. A procedure that produces consistent results is necessary and this paper presents the development of an efficient and reliable procedure based on the quantification of road user costs and construction costs on interchanges. To develop this procedure, a survey of existing expressway interchange types in South Korea was made and 10 basic interchange types and 52 supplementary interchange types were identified. To relate road user costs and construction costs to these interchange types, this research uses two method. First, interchange types were expressed by a set of ramp configurations. Second, road user benefits and construction costs associated with these different interchange types were formulated based on the current national guide of the expressway economical analysis. As a result, it was proved that an interchange type to provide minimum costs could be selected consistently and this research result should be useful for future expressway geometric designs.

• Journal of Korean Society of Transportation
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• v.26 no.6
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• pp.39-47
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• 2008

With dramatic development of IT technology and start of DMB service, installing the DMB equipment in a vehicle for watching TV programs and literal or pictorial traffic information are increasing. Watching the DMB during driving the vehicle could cause visual and cognitive distraction to drivers as much as eating food, operating radio and using mobile phone. However, there is not much empirical research for this topic and no research examined the effect of watching the DMB on driving behaviors in Korea. So, the present study examined the effect of watching the DMB on the driving behaviors with car simulator experiment. Within subject design was used in the study. That is, all subjects drove the vehicle both in the watching DMB condition and the non-watching DMB condition. The results indicated that subjects in the watching DMB condition took longer time to arrive at the destination and operated accelerator and brake pedal rapidly than subjects in the non-watching DMB condition. That is, their overall driving stability was lower than non-watching subjects'. Additionally, we examined the difference among the DMB control conditions (i.e., keypad condition, touch-pad condition and remote controller condition) in the driving behaviors. Finally, we discussed the limitations and the implications of the present study.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.167-175
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• 2018

This research deals, The characteristics of mechanics and behavior of the tube structural systems, It has been investigated and considered conventional theory and case models, It has shown the suitability, The best location, And optimal shape of the unit module system, Considered variables materials of stiffness increase and decrease in hybrid tube structural systems this study carried out adapting analysis of statistical concepts. In a concrete way, This study exams the effect of reducing horizontal displacement and the shear lag phenomenon, Also, The purpose of this study is to utilize the basic data on the design and study of future high-rise hybrid structural system using this research. As a result, The framed- tube structural system does not effectively cope with horizontal behavior of high-rise buildings, The results of using varying material tested resistance factors and lateral loads in hybrid tube structural system, When each material is compared Bracing material is identified as a key factor in lateral behavior. In a ratio of material quantity framed-tube structural system, The level of sensitivity affecting the horizontal displacement is greater then the beam's column, In case of braced tube structural system, Braced appeared to be most sensitive in comparison of material quantity ratio in columns and beams.

• Korean Journal of Health Education and Promotion
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• v.19 no.4
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• pp.1-18
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• 2002

This study identified the health habits affecting health status of industrial workers. Data was collected from 965 workers in 58 companies at Buchon. The research conducted a self-administered questionnaire survey and obtained the workers' health examination records. The results were as follows: 1. Among 965 respondents, men were 82.4%, women were 17.6%, 44.5% were of the 30${\sim}$40 age group, the married were 67.4%, the single were 30.8%, high school graduates were 81.1% and 38.8% were of people who worked between 1 and 5 years 2. As far as the seven health habits, current smokers were 52.8%, people who regularly exercise was 28.5%, 7${\sim}$8 hour of sleep, on the average were 71.4%, people eating breakfast nearly every day were 8.8%, and people eating between meals almost every day were 46.5%. Heavy drinkers who drink 3${\sim}$4 times or more per week were 14.2%, 1${\sim}$2 times per week were 32.6% and the obese were 9.3%. 3, Health status of A and B, estimated by doctors in the health examination were 80.8% and C, D1, D2, the unhealthy were 19.2%. For men, those who reported more than women in unhealthy groups and the results regarding health status reflects those for gender, educational level and age. That is to say that, lower educational level group and over 30 years of age group perceive their health to be worse than the higher educational level and under 30 age group. And these differences were statistically significant. 4. The relationship between health habits and health status were examined based on the odds ratio. Current smokers had a consistently worse health status than a non smokers with a 1.98 odds ratio. The workers who reported eating breakfast rarely or never were more associated with the unhealthy group than the regular breakfast eating group with a 2.96 odds ratio. One or more drink per week had a worse health status than a never or a little drinker with a 1.56 odds ratio. 5. General health habit score and duration of work were selected as significant factors influencing health status from the result of logistic regression analysis. According to the results of this model, the odds ratio of good health status was 2.08 for good health habit score, 1.63 for workers who worked five years or more duration at work. In summary, good health habits were associated with good health status. In particular, the workers who had 5 or more desirable health habits had a significantly better health status than the workers who had 4 or less than 4 good health habits. Therefore, in order to provide the health promotion programs to workers it is necessary to organize clear health management plans based on effective health education and health service perspective. If further research examines health habits and health status using a prospective study design, More precise findings for health promotion program development in the worksite and worksite health management planning.

• Child Health Nursing Research
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• v.19 no.2
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• pp.140-148
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• 2013

Purpose: The aim of this study was to explore the relationship of being from low-income families on children's behavior problems and obesity. Methods: The research design was a descriptive survey study, and the participants were 197 children from low-income families who took part in activities at a local children's center. They were selected through convenience sampling. The participants completed a questionnaire, BASC-2 (Behavior Assessment System for Children). Results: The results are as follows: 22.3% had obesity, a rate higher than that of children in general. Further, 37.3% had attention deficit problems, 33.8% had problems adapting to school and 49% had other adaption problem. There was a gender-specific difference with respect to all of the behavior problems. Conclusion: The results of this study indicate a lack of an identified child policy for behavior problems and health, and suggest a need for various programs and policies which could lead to development of behavior screening programs for children from low-income families.

• Journal of the Korea Safety Management & Science
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• v.21 no.4
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• pp.75-80
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• 2019

Sales of the Korean clothing industry grew to 16.9 percent on-year in 2010, but the growth rate dropped to 3 percent from 2011 to 2016 and the overall market began to slump to 1.1.6 percent in 2017. The competitiveness of clothing companies is also a major sector in logistics capability, and the average logistics cost of domestic clothing companies is 8.3 percent of sales in 2011, higher than the average 8 percent of domestic industries, and 36.4 percent of the total storage cost in 2011, higher than the 28.8 percent share of the total storage cost of domestic companies. As domestic production conditions such as wage hikes and labor disputes worsened in the 1990s, production facilities were rapidly moved overseas, which led many clothing companies to have no production facilities or a minimal production base in Korea and focus on marketing and design capabilities. The total storage capacity and storage efficiency of the logistics center became very important as the products were changed to the form of mass warehousing and small-volume forwarding. Research shows that building column spacing, a model of this research, can affect the amount of hanger rack storage empirically, so for sustainable growth of clothing companies, it is necessary to improve competitiveness in the logistics market by reducing costs and improving efficiency to overcome difficulties in corporate management. Because logistics costs are 8.3 percent and operating profit to sales ratio is 2 percent, it is expected that operating profit will increase by 41.5 percent if logistics costs are reduced by 10 percent. If 10% of storage cost is saved based on storage cost, operating profit is expected to increase by 15% To strengthen the competitiveness of the clothing industry, a reduction in logistics costs is essential. Therefore, the purpose of this study is to provide hints that logistics experts can have empirically small amounts in reducing storage costs through column spacing adjustment of logistics centers that have not been dealt with statistically until now, and to contribute to the continued growth of clothing companies and the development of the domestic logistics industry.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.459-467
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• 2016

This study was conducted to evaluate and identify what factors influence the satisfaction of the users for the fast-growing social network game based on the mobile. To this end, we looked around the variable product characteristic factor, quality and the consumer characteristic factor, user self-determination. Also we surveyed 211 male and female college students. The first finding was that all the sub-factors of the quality factor had positive effects on the satisfaction of the mobile social network games. The second finding was that all the sub-factors of the self-determination factor had positive effects on the satisfaction of the mobile social network games. The third finding was that only the sub-factors of quality had positive relative effects on the satisfaction of the mobile social network games, in the order of playfulness, usability, functionality from the most to the least. The findings of this study are expected to offer meaningful and practical suggestions for the development of high quality game contents for the user convenience, as well as the academic significance, the expansion of game-related area of research through the break from the traditional research trends, technology and engineering point of view and from the PC-based online game.