• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.1
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• pp.94-101
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• 2019

Most of the existing rail structures have undergone a lot of aging since a considerable period of time has passed from completion. In particular, among existing railway bridges, many of the plate girder bridges are older bridges that have lived 40 to 60 years or more. Since the treadmill is directly connected to the girder without the ballast, the running load of the vehicle is directly transmitted to the bridge. Therefore, the shock and noise applied to the bridge are larger than those of the ballast bridge, and the dynamic shock and vibration are also relatively large. Therefore, it is very urgent to develop appropriate maintenance, repair and reinforcement technology for existing steel plate bridge. In this study, the authors introduced the characteristics of embedded rail (ERS) developed for improving the performance of the existing plate girder bridge and the techniques solving the vibration and noise problems. In order to evaluate the vibration and noise reduction performance of ERS, a non-ballast plate girder bridge with 5m length of sleepers installed and a plate girder bridge with ERS were fabricated. And, then, the vibration response generated under the same excitation condition was measured and analyzed. Also, the radiated noise analysis was performed using the vibration response data obtained from the experiment as the input data of the acoustic analysis model. As a result of experiments and analyses, it was confirmed that the plate girder bridge's vibration using ERS was reduced by 15.0~18.8dB and the average noise was reduced by 7.7dB(A) more than the non-ballast bridge.

• Journal of radiological science and technology
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• v.44 no.2
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• pp.117-122
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• 2021

This study is desinged to examine for radiation protection effect of Protaetia Brevitarsis Larvae extracts on the blood and prostate of male rat as a natural radiation protection agent. 5 groups were classified using 90 male rat as experimental animals. Each group was clssified as normal control group (NC Group), the group administered protaetia brevitarsis larvae extracts (PBE Group), irradiated group (IR Group), irradiated group after administration of protaetia brevitarsis larvae extracts (PBE+IR Group), the group administered protaetia brevitarsis larvae extracts after irradiaton (IR+PBE Group). In IR Group, 7 Gy/h of Co-60 gamma ray was irradiated to SD rats. In PBE+IR Group, protaetia brevitarsis larvae extacts wewe injected at 200 mg/kg/day for 14 days before irradiation, In IR+PBE Group, protaetia brevitarsis larvae extract was injeted after irradiation. On the 1, 7 and 21 days after irradiation, the experimental animals were sacrificed to evaluate the changes in blood cell component, superoxide dismutase (SOD) activity, histopathological evaluation of the liver and prostate gland. As a result, the PBE+IR Group and IR+PBE Group showed a significantly recovery of white blood cell (p<0.01, p<0.01), platelet (p<0.01, p<0.01) than the IR Group. It was also confirmed that SOD activity of PBE+IR Group (p<0.01) and IR+PBE Group (p<0.01) was significantly increased than the IR Group. Also PBE+IR Group and IR+PBE Group showed less inflammatory reactions of cystoplasm in the prostate gland than the IR Group. In conclusion, the protaetia brevitarsis larvae have radioprotection effect against blood and prostate gland. It is expected to be useful for research of radiation protection agent.

• Applied Chemistry for Engineering
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• v.22 no.4
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• pp.367-375
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• 2011

Succinic acid ester derivatives have been used as additives for the base oil of metal working fluids and pressure working oils. In this paper, a series of succinic acid alkyl half-esters were synthesized with over 97% yields by ring-opening reaction of succinic anhydride and fatty alcohol and were soluble in 100 N base oil within 1 wt% concentration. The structures and purities of ester derivatives were confirmed by $^1H-NMR$ and FT-IR spectrum and GC analysis. Anti-corrosion properties of the esters in sea water were evaluated through ASTM D665 method and weight loss method and compared to that of succinic alkyl esters without carboxylic acid group in the molecule. As the results, anti-corrosion properties of succinic acid alkyl half-esters with carboxylic acid group were better than those of succinic acid alkyl esters without carboxylic acid group. And, Anti-corrosion properties of the esters with a shorter alkyl chain of high concentration showed better performance than those with longer alkyl chain of low concentration. Inhibition efficiency % (IE%) of the esters was over 95% in the concentration of 80 ppm and corrosion rate (CR) was below 0.3 mm/year at the same concentration. Thus, the corrosion properties of succinic acid alkyl half-esters result from the carboxylic acid groups in molecules.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.212-220
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• 2021

National R&D investment has steadily increased, reaching number 5 in the world as of 2018. However, for public technology commercialization, the level of discovery of policy models through various cooperation initiatives between government ministries is insufficient, and the performance system that can spread technology commercialization is also limited. In this respect, in order to create results in public technology commercialization, it is necessary to prepare alternatives to strengthen multi-ministerial policy cooperation and increase policy execution power. In this paper, we analyzed the current state of national R&D projects by major ministries and suggested an optimized technology commercialization plan through analysis of the structure, budget, and form of each project. In particular, an alternative in terms of policy efficiency was suggested by analyzing the problems of policy discovery that have not been studied previously. This study is of great significance in that it diagnosed problems of public technology commercialization in terms of the lack of systematic research on public technology commercialization and suggested policy advancement for the spread of technology use and the strategic direction in terms of commercialization.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.215-228
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• 2021

The purpose of this qualitative study was to identify cultural factors among older Americans that could influence them to accept new welfare technologies. This study also explored how social and cultural-based plans could increase the acceptability of welfare technologies for improving the quality of life of older adults in the future. In-depth interviews were conducted with ten professionals who work with older adults. The collected interview data were subsequently analyzed using a two-cycle open coding process. The data analysis generated 29 codes that were organized into 7 primary codes, or categories, and 22 secondary codes nested within the primary codes. Several themes were identified: individualism, family-oriented culture, pragmatism, low-context culture, privacy, fun-seeking culture, and a less hierarchical culture. These findings will inform the development of a future survey to examine the relationship between older adults' intentions when using technology and socio-cultural factors in community settings. In order to explore the different impact levels of the cultural factors found in this study, the future study will need to include measures for identifying socio-cultural variations among individuals in one country or across countries.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.2
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• pp.172-181
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• 2022

Objectives: In order to reduce the burden on employers and increase the reliability of measurement results, improvements to the provisions related to the work environment measurement reporting system, such as the current Occupational Safety and Health Act and its Enforcement Rules, are planned. This study aimed to suggest improvements for the work environment measurement reporting system through a survey and Delphi investigation. Method: This survey included workplaces (health managers), national institutions (the Ministry of Employment and Labor) that use the results of the work environment measurement reporting system for policy and supervision purposes, and work environment measurement institutions that enter the results were included. In addition to the survey, we tried to derive results through meetings with stakeholders and expert advisory meetings. Results: It is difficult to abolish or partially improve the reporting system under the Enforcement Regulations of the Occupational Safety and Health Act at this point because the opinions of workplaces, supervisory agencies, and measuring agencies differ in terms of its intended purpose and use. In the case of high-exposure harmful factors (over 50% on the basis of exposure) in the "comprehensive opinion" described in the work environment measurement results table, it is necessary to insert unit of work with exposed harmful factors, exposure factors, and current conditions in checklists or tables so that they can be reflected in government policies. In the case of workplaces that are feared to be highly exposed to substances subject to measurement, it seems desirable to improve them so that industrial health instructors registered with the Korea Safety and Health Agency or local labor offices can provide technical guidance. As an improvement plan to increase the reliability of data and the use of big data, it is necessary to improve the input method for processes and jobs. Conclusion: The laws and regulations of the work environment measurement reporting system are difficult to revise due to a lack of consensus among current stakeholders, but improvements can be achieved by improving the Ministry of Employment and Labor's notifications and other means. In addition, in order to effectively utilize the data from the K2B system, it is necessary to improve the input method for processes and jobs.

• 한국노년학
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• v.40 no.2
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• pp.291-309
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• 2020

In this study, the behavioral model of Andersen and Newman(1973) was applied to identify the factors influencing the use of senior centers by the elderly in the community, and the mediating effect of user satisfaction was improved to improve the satisfaction of seniors using the Senior Center and operate the Senior Center. This study attempted to suggest policy and practical alternatives for activation. The subjects were 578 elderly people using 2,283 senior centers in Busan. As a result, the factors influencing the total usage period of the Senior Center were analyzed by age and type of potential factors among the leading factors, and the factors affecting the total number of days of senior center usage during the week were gender, age, and education level among the preceding factors. Appeared. Factors affecting user satisfaction as a parameter were analyzed as subjective health status among gender, age, and desire factors among preceding factors. As a result of verification of mediating effect of user satisfaction, there was a partial mediating effect between age and total use of Senior Center, full mediating effect between gender and days of Senior Center use, and partial mediating effect between age and Senior Center use days. Analyzed. According to the purpose and main findings of the study, the policy and practical suggestions for activating the satisfaction and use of Senior Center are as follows. First, program development and support according to the characteristics of senior center users are required. Second, there is a need to characterize per-path according to senior center type and regional environment. Third, there is a need to improve and raise the support standards for senior center operating expenses.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.1
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• pp.29-36
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• 2023

This study proposes a spirometry reference equation suitable for Asian migrant workers undergoing special health examinations. The study participants were divided according to their region: Central Asia, Northeast Asia, and South Asia Pacific. We confirmed results of the spirometry analysis of migrant workers and the interpretation consistency between the prediction equations. Based on this data, we propose a reference equation suitable for domestic migrant workers and suggest a scaling factor applicable to the spirometer wherein the reference equation is not easily applicable. The kappa-values obtained for men and women, respectively, between the global lung function initiative 2012 (GLI2012)-Southeast Asian and the Southeast Asian equations were 0.819 and 0.770, between the GLI2012-Southeast Asian and the South Asian equations were 0.881 and 0.866, and between the GLI2012-Northeast Asian and the Central Asian equations were 0.831 and 0.833. We propose applying the GLI2012-Northeast Asian equation for Northeast Asian and Central Asian countries, whereas the GLI2012-Southeast Asian equation was found to be more suitable for predicting Southeast Asian and South Asian populations. For spirometry, we recommend applying a scaling factor of 0.87 to the Dr. Choi equation, wherein the GLI2012-Southeast Asian equation is not applicable.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.146-164
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• 2022

Recently, the Korean government promoted the construction of metropolitan express subway to connect major transportation hub in the metropolitan area within 30 minutes. Most stations of the metropolitan express subway are connected to existing subway stations, so the importance of transfer increased. Although many studies have been conducted on the effect of transfer penalty on route choice, there are few studies on the transfer behavior of the metropolitan express subway. Therefore, in this study, a transfer behavior analysis was conducted on the Shinbundang Line, a representative metropolitan express subway. To analyze the transfer behavior according to the degree of traffic congestion and the presence of fare payment, route choice models were made using transport card data divided according to week, time, and user characteristics. As a result of the analysis, users of the metropolitan express subway had greater disutility to the transfer waiting time compared to the transfer moving time. Furthermore, especially during the peak time, EIVM(Equivalent in-vehicle minutes) of the transfer waiting time was 3.51. In this study, EIVM for metropolitan express subway users were analyzed to be 2.6 minutes, which is significantly lower than the results of previous studies on subways. This suggests that there is a difference in the transfer penalty between subways and metropolitan express subway, and that it is necessary to apply the transfer penalty between subways and express subway differently when forecasting subway traffic demand.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.97-114
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• 2022

Unlike ground roads, the on-ramp merging section of underground roads cannot be seen by drivers of main road due to tunnels. In this study, a driving simulator was used for analysis, and virtual driving experiments were carried out to assess the driver's visibility for different design factors. The driver's driving behavior was analyzed by setting scenarios considering the length of chevron markings and the approach speed from the main road. The results of the analysis were used to determine the design factors for ensuring visibility when constructing the virtual driving environment for each scenario. These factors, including speed, lane change points, and driver's gaze ratios, were reviewed for significance using a statistical approach. As a result, in scenarios with a higher approach speed from the main road, it was discovered that there was a difference in driver's behavior between specific scenarios depending on the length of the section with chevron markings. Based on these findings, this study suggests implications and feasible solutions to improve driver safety on the on-ramp merging section of underground roads.