• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.5
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• pp.113-129
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• 2021

Recently, traffic congestion in the city is continuously increasing due to the expansion of the living area centered in the metropolitan area and the concentration of population in large cities. New road construction has become impossible due to the increase in land prices in downtown areas and limited sites, and the importance of efficient data-based road operation is increasingly emerging. For efficient road operation, it is essential to classify appropriate scenarios according to changes in traffic conditions and to operate optimal signals for each scenario. In this study, the Dynamic Time Warping model for cluster analysis of time series data was applied to traffic volume and speed data collected at continuous intersections for optimal scenario classification. We propose a methodology for composing an optimal signal operation scenario by analyzing the characteristics of the scenarios for each data used for classification.

• Journal of the Korea Society for Simulation
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• v.19 no.2
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• pp.137-145
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• 2010

This study presents an RTS(Real-time Traffic System) based on an LBS(Location Based Service) using 5.8~5.9GHz RSU(Road Side Unit). The proposed LBI(Location based Broadcast system on ITS) is a local information-based service supported by RSU for drivers, which has a feature of convergence between T-DMB system and ITS-based RTS. The convergence of local broadcasting station and ITS is realized by two-way communication and supports LBS(Location Based Service) by identifying of vehicle's location using RSU. Real-time information delivery and various services could be provided by information exchanges between LMM and local broadcasting stations. Furthermore, conventional technical limitations have been solved mutually such as transmission area limitation in RTS and one-way communication problem in T-DMB. This support real-time two-way communication to each driver. Therefore, it can be expected that traffic dispersion effects and services expansion for drivers by RTS and LBI. Finally, it is proposed to built and implement test-bed around institute.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.7-16
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• 2015

PURPOSES : This study was performed to determine a systematic approach for measuring the coefficient of thermal expansion (COTE) of concrete specimens. This approach includes the initial calibration of measurement equipment. Test variables include coarse aggregate types such as natural aggregate, job-site produced recycled concrete aggregate, and recycled aggregate processed from an intermediate waste treatment company. METHODS : First, two cylindrical SUS-304 specimens with a known COTE value of $17.3{\times}10^{-6}m/m/^{\circ}C$. were used as reference specimens for the calibration of each measurement system. The well-known AASHTO TP-60 COTE apparatus for concrete measurement was utilized in this study. Four different measurement apparatuses were used with each LVDT installed and a calibration value was determined using each measurement apparatus. RESULTS : In the initial experimental stage, calibration values for each measurement apparatus were assumed to be almost identical. However, using the SUS-304 samples as a reference, the calibration values for the four different measurement apparatuses were found to range from 3.49 to $8.86{\times}10^{-6}m/m/^{\circ}C$. Using different adjusted values for each measurement apparatuses, COTE values for the three different concrete specimens were obtained. The COTE value of concrete made with natural coarse aggregate was $9.91{\times}10^{-6}m/m/^{\circ}C$, that of job-site produced recycled coarse aggregate was $10.45{\times}10^{-6}m/m/^{\circ}C$, and that of recycled aggregate processed from the intermediate waste treatment company was $10.82{\times}10^{-6}m/m/^{\circ}C$. CONCLUSIONS : We observed that the COTE value of concrete made from recycled concrete aggregates (RCA) was higher than that of concrete made from natural coarse aggregate. This difference is due to the fact that the total volumetric mortar proportion in the RCA mix is higher than that in the concrete mix made with natural coarse aggregate.

• The Journal of the Convergence on Culture Technology
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• v.8 no.4
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• pp.407-413
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• 2022

In this study, the empirical formula for evaluating cable tension based on long-term measurement for about 3 years according to temperature change was proposed by proving the correlation between the expansion joint displacement of the upper road bridge and the cable tension of the lower railway bridge. The tension prediction results using the empirical formula for tension evaluation each cables proposed in this study were found to be in good agreement with the cable tension using the vibration method within 3%. Therefore, it was analyzed that it could be applied together with the vibration method that was an experimental technique, to predict and evaluate the cable tension in serviced railway steel composite bridge. As a result of applying the estimated temperature calculated by the empirical formula for expansion proposed in this study to the empirical formula, it was analyzed that a high level of reliability could be secured when compared with the vibration method. Therefore, it is judged that the empirical formula for cable tension evaluation reflecting the estimated temperature proposed in this study can be used to predict the tension of cables according to climate change in the future and establish a maintenance plan.

• International Journal of Highway Engineering
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• v.18 no.3
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• pp.47-57
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• 2016

PURPOSES : This study aims to examine the differences between the existing traffic demand forecasting method and the traffic demand forecasting method considering future regional development plans and new road construction and expansion plans using a four-step traffic demand forecast for a more objective and sophisticated national highway maintenance. This study ultimately aims to present future pavement deterioration and budget forecasting planning based on the examination. METHODS : This study used the latest data offered by the Korea Transport Data Base (KTDB) as the basic data for demand forecast. The analysis scope was set using the Daejeon Metropolitan City's O/D and network data. This study used a traffic demand program called TransCad, and performed a traffic assignment by vehicle type through the application of a user equilibrium-based multi-class assignment technique. This study forecasted future traffic demand by verifying whether or not a realistic traffic pattern was expressed similarly by undertaking a calibration process. This study performed a life cycle cost analysis based on traffic using the forecasted future demand or existing past pattern, or by assuming the constant traffic demand. The maintenance criteria were decided according to equivalent single axle loads (ESAL). The maintenance period in the concerned section was calculated in this study. This study also computed the maintenance costs using a construction method by applying the maintenance criteria considering the ESAL. The road user costs were calculated by using the user cost calculation logic applied to the Korean Pavement Management System, which is the existing study outcome. RESULTS : This study ascertained that the increase and decrease of traffic occurred in the concerned section according to the future development plans. Furthermore, there were differences from demand forecasting that did not consider the development plans. Realistic and accurate demand forecasting supported an optimized decision making that efficiently assigns maintenance costs, and can be used as very important basic information for maintenance decision making. CONCLUSIONS : Therefore, decision making for a more efficient and sophisticated road management than the method assuming future traffic can be expected to be the same as the existing pattern or steady traffic demand. The reflection of a reliable forecasting of the future traffic demand to life cycle cost analysis (LCCA) can be a very vital factor because many studies are generally performed without considering the future traffic demand or with an analysis through setting a scenario upon LCCA within a pavement management system.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.597-607
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• 2002

Electric arc furnace and converter slag are produced by about 6 millions tons in Korea at 2000 year. But compared with blast furnace slag, those are utilized only in unvalued material like landfill and road construction. There are unstable materials, like free CaO, in electric arc furnace and converter slag at steel-manufacturing process. This might cause volume expansion in concrete, if electric arc furnace and converter slag aggregates were used in concrete. This expansion may reach to crack or collapse of concrete. It is therefore settled by standard specification for concrete that electric arc furnace and converter slag aggregates have not to use in concrete. First of all, volume stability and stabilized process should be solved in electric arc furnace and converter slag aggregate to use in concrete. In this study, 6 types of aging are evaluated for effects of stabilization to reduce the expansion of electric arc furnace and converter slag. h converter slag aggregate, these types of aging are not good for volume stability for concrete aggregate, and even if converter slag aggregate is treated with aging, concrete with it has some problems that strength is reduced with curing days. But in electric arc furnace slag aggregate treated with hotwater and steam aging, the expansion of electric arc furnace slag aggregate is reduced about two times than that of converter slag aggregate, and electric arc furnace slag aggregate concrete has good results in strength compared with control concrete using crushed stone.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.271-274
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• 2007

Lately, there are actively proceeding in making a plan for subway construction, a high-speed railway construction and a expansion of road and also all kinds of large-scaled construction in Korea. Construction works were delayed from noises and vibrations occurred by usage of a large-sized construction equipments and driven and also blast or there were often stopped from them under construction. Therefore, this study was modeling operation of the cyclic loading and conforming effects from grasping displacement-changing method through a variable analysis.

• Conservation Science in Museum
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• v.10
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• pp.29-42
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• 2009

This paper explores the types (species of trees) of 25 pieces of waterlogged wood excavated from the area between Gwangju and Jangseong during road expansion by the Gwangju National Museum. These 25 pieces of wood include nine pieces of Quercus (Lepidobalanus Cerris)sp., six pieces of Quercus (Lepidobalanus Prinus)sp., three pieces of Castanea sp., two pieces of Salix sp., one piece of Alnus sp., one piece of Prunus sp., one piece of Morus sp., one piece of Chionanthus sp., and one piece of Acanthopanax sp.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.405-412
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• 2004

This study measures the investment effects of railroad industries on Korean economics, using the table of industry relation analysis. Until now, few studies have analyzed the economic effects of railroad in Korea so that this study can have a big implication for transportation policies in making decisions on its investment level as top priority. This study finds that railroad investment effects are larger than those of road on the national economics and, thus, impling that the expansion of railroad investment is required to grow continuously national economics as well as a major modal of transportation networks.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.217-222
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• 2003

The steel slag, a by-product which is produced during the manufacture of steel by refining pig iron, is mainly used as road materials after aging it. It is necessary to age steel slag for long time in air because the reaction with water and free-CaO in steel slag could make the expansion of volume. This problem prevents steel slag from being used as aggregate for concrete. But steel slag used in this study was controled by an air-jet method which rapidly cools substance melted at a high temperature. Rapid cooling prevents from generation of free-CaO in steel slag. In this study, properties of steel slag manufactured by air-jet method and mortar used it were investigated. As results of this study, free-CaO contents were controled under 1%. Mortar used this steel slag demanded to lower water contents, higher compressive strength and lower drying shrinkage than the basic mortar in the same condition.