• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.702-708
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• 2016

The railway signaling system has evolved to maximize its safety and maintainability based on the experiences in the construction and operation of railway systems. The newly developed systems was established to cope with the changes in an operating environment. In the process of a transition to the new system, both the existing ATS (Automatic Train Stop) and new ATP/ATO (Automatic Train Protection/Automatic Train Operation) systems are operating simultaneously in parallel. In this situation, modifications of the conditions of the interlocking diagram and logic are necessarily required on the existing ATS systems due to the frequent improvements in signaling equipment. This paper reports the enhancement of safety and operational efficiency of the system through an improvement of the security and the interlocking conditions of the existing ATS systems. The independent display of signals for each track was ensured to avoid giving the effect of On/Off signals for the selected track on the opposite side, and the security was improved by adjusting the position and interlocking conditions. In addition, the increased traffic density of railway systems was achieved by removing the unnecessary conditions and detailed signal display, which resulted in enhanced operational efficiency.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.2
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• pp.175-187
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• 2014

The subways play an important part in serious traffic problems. Almost seven million citizens a day are using subways as a means of traffic communication in the Seoul metropolitan city in 2012. However, the subway system is a semi-closed environment, so many serious problems occurred in subway stations and injured passengers' health. Platform screen doors (PSD) are expected to prevent negligent accident such as injury or death from falling and improve the air quality of the subway station. Installation of PSD at stations in Seoul metropolitan subway had been completed in December 2009. Consequently, the underground transportation system became a closed environment, so the air quality has improved the platforms, but it has deteriorated in the tunnels. Especially, the subway cabin has many doors, and the doors are frequently opened and closed. For this reason, the effect of door opening on subway cabin, dust flow inside the subway cabin. In this process, the maintenance work may influence the health of people who work underground, as well as that of subway users (passengers). In this study, we measured air quality inside and outside of the subway cabin line 2 in Seoul, Korea. This study focused on the investigation of Indoor Air Quality (IAQ) and measurement target pollutants are PM10, CO, $CO_2$, $NO_2$, $O_3$. It was found that levels of PM10, $CO_2$, and $NO_2$ inside subway cabin line 2 exceeded the Korea IAQ standard. Concentrations of PM10, $CO_2$, and $NO_2$ inside of the cabin are higher than outside of the cabin (Indoor Outdoor ratio is higher than 1.). Concentrations of CO, $O_3$ inside of the cabin are lower than outside of the cabin (Indoor Outdoor ratio is lower than 1.). There is a high correlation between $CO_2$ and passengers inside of the cabin and PM10 is only the weakest correlation with passengers. Therefore, it is important to find out the emission source of $NO_2$. The results of this study will be useful as fundamental data to study indoor air quality of a subway cabin.

• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.1
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• pp.63-71
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• 2024

Through the development of construction technology, various construction projects such as redevelopment projects, undergrounding of roads, expansion of subways, and metro railways are being carried out. However, this has led to an increase in the number of construction projects in existing urban centers and neighborhoods, resulting in an increase in the number of damages and disputes between neighboring buildings and residents, as well as an increase in safety accidents due to the aging of existing buildings. In this study, digital data was applied to a graphics program to objectify the progress of cracks by comparing the creation of cracks and the increase in length and width through photographic images and presenting the degree of cracks numerically. Through the application of the program, the error caused by the subjective judgment of crack change, which was mentioned as a shortcoming of the existing field survey, was solved. It is expected that the program can be used universally in the building diagnosis process by improving its reliability if supplemented and improved in the process of use. As a follow-up study, it is necessary to apply the extraction algorithm of the digital graphic data program to calculate the length and width of the crack by itself without human intervention in the preprocessing work and to check the overall change of the building.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.617-623
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• 2020

Urban railroad vehicles carry many passengers and are the core of an urban railroad transportation system. Therefore, the dynamic performance of the vehicle must be ensured. Dynamic behaviors such as the vibration and ride comfort of railway vehicles are affected by the structure of the suspension system. We analyzed the dynamic behavior of a railway vehicle according to the suspension system of an urban railway vehicle, which is mainly operated in Korea. For two types of vehicles with different suspension structures, the vibration of the vehicles on railway tracks was measured, and dynamic behavior characteristics such as vibration, ride, and vibration reduction rate were analyzed. The result of the test shows that the vibration performance of the body is superior to that of B-bogie in the lateral direction and that of A-bogie in the vertical direction. Overall, the ride quality of the A-bogie car is superior to that of B-bogie. When analyzing the vibration attenuation rate of primary suspension system, the vibration attenuation performance of B-bogie with coil spring was superior to that of A-bogie with a conical rubber spring. The secondary suspension system has better vibration attenuation performance for A-bogie with air springs compared to coil springs.

• Journal of Labour Economics
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• v.26 no.1
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• pp.111-151
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• 2003

This study attempted to analize the hazard rate from unemployment and the influncing factors on the rate by regions. The data this study uses is Korea Labor Institute Panal Study(1998-2001) and the models are hazard analysis and Cox model. The results of hazard analysis are as follow. In capital and it's vicinity, the duration of unemployment is shorter than other regions even if the unemployment rate is higher. The labor market segmentation is confirmed between capital and it's vicinity region and other regions. Kyungsang region is higher in the unemployment hazard rate than Chunla or Chungchung regions. The duration of unemployment in capital and it's vicinity is 9.29 months comparing 11.86 months in the other region. The difference is statistically significant by the significance level 0.001. The duration of unemployment in Kyungsang is 6.96 months comparing 10.95 months in Chunla region. The Cox results which indicate the influncing factors on the hazard rate are as follow. In the regions like non-metro cities and non-capital and vicinitiy, the factors such as female, tenure, wage earners, manufacturing, wholesale and retale decrease the hazard rate. The results indicate that active labor market policies region by region are needed in Korea, especially for the marginal unemployed workes from non flourishing sectors.

• Korean Journal of Heritage: History & Science
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• v.44 no.4
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• pp.4-17
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• 2011

Oegosan Onggi Village can be characterized by having industrial significance and cultural significance of Onggi. However Onggijang(Onggi maker) worked in poor conditions because the village was in the limited development district. Throughout the new millenium phenomenon of Well-being, the awareness of cultural values has been increased while local government designated Onggi as Local Intangible Cultural Heritage(ICH). In this condition, Ulsan metro city and Ulju county paid attention to Onggi Village as tourist attractions. First, they worked improving condition of village through Cultural Tourist Attraction Plan. Second, they extended their participation in Onggi Festival so the festival growed. Third, they designated Onggijang in Village as Local ICH. These activities were the effort in order to revitalize the village, however the cultural tourist attraction plan was solely centralized into tourist attractions. Thus, the work condition of Onggijang was not considered sufficiently so the work condition had become more inconvenient than the previous situation. In the case of Onggi festival, the outward development has been accomplished in accordance with the growth of festival scale and visitors, while the identity of festival had been weaken so the Onggijang barely attended the Onggi festival. The designation of ICH was also the unilateral decision, Onggijang had been in the conflict relationship between Onggijang concerning the craftsmanship and maintenance of the ICH. Local Government had power on their Intangible Cultural Heritage(ICH). Therefore we need to seek for role and functions as community on ICH.

• Journal of the Korea Concrete Institute
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• v.26 no.4
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• pp.507-515
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• 2014

Although the construction joints of a concrete structure are properly treated with some measures, leakage has frequently occurred. A series of tests on the bond characteristics between new and old concrete were carried out in this study, assuming that the leakage at the construction joints has certain relationship with the bond of concrete. To assess the bond characteristics under various conditions, a number of specimens were made that have an interface between new and old concrete and bond strength, flexural strength and splitting tensile strength were measured. Main test variables are type and amount of mineral admixtures, treatment method of the interface and type of waterstops. In addition, the effects of placing interval between the concrete and of the age of the strength tests were investigated. The test results showed a slightly increased bond strength when applying mineral admixtures, which can be attributed to the interface filled with the calcium silicate hydrate that is formed by pozzolanic reaction. On the other hand, the bond strength was higher when the interface was treated rough and dry, and the roughness of a waterstop affected the bond capacity of the waterstop. Also, an assessment is required that considers the type of strength test because the bond strength varied according to the test methods.

• Journal of Digital Convergence
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• v.18 no.5
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• pp.25-31
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• 2020

This study analyzes the effects of aging workforce on human capital and the per capita gross regional domestic product, using regional panel statistics from 1995 to 2017. According to the results of the two-stage least-squares panel regression analysis reflecting the fixed effects by region, the aging of the labor force had no effect on the human capital employment ratio and per capita gross domestic product in the metropolitan cities, but reduced human capital and per capita gross domestic product in the provinces. The share of service businesses had a positive effect on human capital in metropolitan cities, but the effect was not significant in the provinces. Human capital significantly contributed to the increase in per capita gross regional domestic product in the metropolitan cities, but the physical capital stock significantly contributed to the increase in per capita gross regional domestic product in the provinces. The results of this study suggest that the human capital job policy and the per capita regional GDP growth policy due to the aging workforce may be different between metropolitan cities and provinces.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.379-385
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• 2019

The purpose of this study is to investigate the damage status of wood sleepers on concrete track of urban transit at different locations and to analyze the causes of damages. In addition, the turnout maintenance history during the service period of about 24 years was analyzed in conjunction with the train passing tonnage and that was to compare the current repair history. The most frequent damage components were rail, tie plate, spike and wooden sleeper. And, the damage caused by the defect of the rail fastening system such as spike and tie plate according to the deformation of the wooden sleeper was analyzed as the main type of damage. As a result, the damage of track components of turnout system was on the increase because they are directly affected by the train passing tonnage. The supplementary points of the check sheet for current turnout maintenance were derived and the improvement proposal was suggested based on the research results.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.667-674
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• 2022

In this study, the correlation between the damage type and operating conditions of the sleepers was analyzed based on the design data and visual inspection results for the concrete sleepers of the sleeper floating track (STEDEF) that have been in operation for more than 20 years. It appeared in the form of cracks, breakages, and breaks in the concrete at the center and tie bar contact and buried areas. As a result of the numerical analysis, it was analyzed that the change in the left and right spring stiffness of the sleeper resilience pad increases the maximum stress, tensile stress, compressive stress, and displacement of the concrete sleeper, and stress concentration in the concrete at the tie bar contact area. It was proved analytically that the sleeper resilience pad can affect the damage of the concrete sleeper. Therefore, damage of concrete sleepers in the sleeper floating track in urban transit could be caused by changes in spring stiffness of sleeper resilience pads. It was reviewed that preventive maintenance such as improvement and timely replacement of sleeper resilience pads was necessary.