• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.73-80
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• 2008

ALINEA algorithm, which is one of the best on-ramp metering algorithms, was designed to control the traffic volume from on-ramp in order to maintain the optimal occupancy rate of the detectors installed downstream of the merge area. But, the reliability of occupancy rate estimated from the loop detectors, which are used most commonly in Korea, is relatively lower than other parameters such as speed and volume. Moreover, because occupancy rate depends on the length of loop detectors and site, lots of calibration work is required whenever they are installed in order to estimate the occupancy rate. Therefore, there exists room for improvement of ALINEA algorithm because only occupancy rate having some problems is considered as a control parameter in ALINEA algorithm. Practically it is difficult to measure or perceive the occupancy rate for traffic engineers and drivers. On the other hand, speed can be good alternative which can overcome the defect induced by using occupancy. In this study, occupancy based ALINEA algorithm is converted to speed based ALINEA assuming the linear relationship between density and speed.

• Journal of Environmental Health Sciences
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• v.45 no.5
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• pp.487-496
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• 2019

Objective: The purpose of this study was to create soil contamination maps using QGIS (Quantum Geographic Information System) and suggest selection methods for soil pollution sources for preferential investigation in a soil contamination survey. Method: Data from soil contamination surveys over five years in Gyeonggi-do Province, South Korea (2013-2017) were used for making soil contamination maps and analyzing the density of survey points. By analyzing points exceeding the concern level of soil contamination, soil pollutant sources for priority management were identified and selection methods for preferred survey points were suggested through a study of the model area. Results: A soil contamination survey was conducted at 1,478 points over five years, with the largest number of surveys conducted in industrial complex and factory areas. Soil contamination maps for copper, zinc, nickel, lead, arsenic, fluoride, and total petroleum hydrocarbons were made, and most of the survey points were found to be below concern level 1 for soil contamination. The density of the survey points is similar to that of densely populated areas and factory areas. The analysis results of points exceeding the criteria showed that soil pollutant sources for priority management were areas where ore and scrap metals were used and stored, traffic-related facilities areas, industrial complex and factory areas, and areas associated with waste and recycling. According to the study of the model area, the preferred survey points were traffic-related facilities with 15 years or more since their construction and factories with a score of 10 or more for soil contamination risk. Conclusion: Soil contamination surveys should use GIS for even regional distribution of survey points and for the effective selection of preferred survey points. This study may be used as guidelines to select points for a soil contamination survey.

• Journal of the Korean Regional Science Association
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• v.40 no.2
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• pp.57-73
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• 2024

The purpose of this study is to establish the central hierarchy and urban spatial structure of Daejeon in 2040 using differentiated analysis indicators. In order to establish a central hierarchy in the future urban space of Daejeon City, three indicators were derived: population density, use of buildings (commercial, office, residential, etc.) and traffic volume data(KTDB). The results of analyzing the center hierarchy using indicators are as follows. First, the primary centers responsible for urban (core) functions are set in three areas, including Dunsan downtown, the original downtown (Daejeon Station area, designated as a special urban convergence zone), and Doan New Town, and the secondary centers corresponding to sub-city centers (regional bases). was set at 9, 10 tertiary centers corresponding to regional centers (living area centers), and a center hierarchy was established with 5 new specialized bases. Second, new secondary and tertiary centers emerged that were different from the center hierarchy in the 2030 Daejeon Urban Basic Plan. The three indicators used in this study yielded meaningful results in establishing urban spatial structure and central hierarchy that can secure urban competitiveness.

• Journal of Ecology and Environment
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• v.29 no.2
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• pp.165-169
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• 2006

As a Biodiversity Management Plan in S. Korea, barley fields are being prepared for the wintering migratory birds. However, the effectiveness of barley fields as a feeding habitat has not been evaluated. In 2003/04 wintering period, we installed exclosures in the barley fields to evaluate the waterfowl grazing effectiveness. Approximately 8,000 waterfowls used the Dongup Reservoir System and utilized the barley fields during the daytime. The white-fronted goose Anser albifrons occupied more than 90% of the all barley-feeding waterfowls. Waterfowls significantly impacted to the shoot density and biomass of barley. In the closed plot, barley shoot density gradually increased to $267{\pm}27/m^2$ in January, 2004. Shoot density in open plots (site 1) declined sharply from.15 December ($189{\pm}18/m^2$) to 5 January 2004 ($25{\pm}11/m^2$). However, barley shoot density in open plots (site 2) was stable in January 2004 because of human disturbances. The changes in barley biomass and shoot density showed similar trend in both open and closed plot. From the exclosure experiment, it was clear that barley fields were important feeding habitat for wintering waterfowls in this area. Further, human disturbances such as noise from traffic and other human activities (farming and hiking) had significant impact on waterfowls' grazing activity. Collectively, winter barley fields were effective for waterfowl feeding, but the location of barley fields should be carefully selected for the maximum utilization of the barley feeding.

• Journal of Korean Society of Transportation
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• v.27 no.3
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• pp.161-168
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• 2009

The ubiquitous transportation system environments make it possible to collect each vehicle's position and velocity data and to perform more sophisticated traffic flow management at individual vehicle or platoon level through V2V and V2I communication. It is necessary to develop a new traffic management paradigm to take advantage of the ubiquitous transportation system environments. This paper proposed a preventive congestion management algorithm for uninterrupted flow, whose goal is to minimize the incident potential and maximize the productivity by maintaining traffic flow stability. The algorithm includes the following steps: Processing the raw data to produce the 3-dimension speed/flow/density profile and to produce the platoon profile and the shock wave profile, Determining the traffic state and the flow stability based on the processed data, Deciding the desirable speed the according the traffic flow state, and finally Providing the desirable speed information. It remains as further work to perform field experiments and calibrate the algorithm parameters.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.318-325
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• 2015

Korea has very strong shipbuilding industry in the world, so many new ships are constructed in Korean shipyards. These built vessels are carrying out sea trial at sea before delivering to shipowner, and sea trial ships cause navigation risk to other passing vessels to accomplish sea trial tests as quick turning, zigzag maneuvering and crash astern etc. in traffic congestion conditions. It occurred more than 1 collision accident related sea trial for recent 5 years. It has been increased about 30% of risk because of navigation of sea trial vessel by marine traffic flow simulation. This paper analyzed marine traffic density surveyed by AIS data for 7 days, and investigated position of marine accidents for 5 years in Korean coastal waterway, it established the sea trial prohibition areas as 10/100 level of total marine traffic volume, which is considered no danger for ship operator. This analyzed maritime safety law for setting of the prohibition waters to propose the basic legal system. It makes contribution to marine pollution prevention by setting of the sea trial prohibition water to improve the ship's navigation safety.

• Journal of Radiation Protection and Research
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• v.27 no.3
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• pp.189-198
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• 2002

The time for evacuation of residents in emergency planning zone(EPZ) of Uljin nuclear site in case of a radiological emergency was estimated with traffic analysis. Evacuees were classified into 4 groups by considering population density, local jurisdictions, and whether they ate residents or transients. The survey to investigate the behavioral characteristics of the residents was made for 200 households and included a hypothetical scenario explaining the accident situation and questions such as dwelling place, time demand for evacuation preparation transportation means for evacuation, sheltering place, and evacuation direction. The microscopic traffic simulation model, CORSIM, was used to simulate the behavior of evacuating vehicles on networks. The results showed that the evacuation time required for total vehicles to move out from EPZ took longer in the daytime than at night in spite that the delay times at intersections were longer at night than in the daytime. This was analyzed due to the differences of the trip generation time distribution. To validate whether the CORSIM model fan appropriately simulate the congested traffic phenomena assumable in case of emergency, a benchmark study was conducted at an intersection without an actuated traffic signal near Uljin site during the traffic peak-time in the morning. This study indicated that the predicted output by the CORSIM model was in good agreement with the observed data. satisfying the purpose of this study.

• Journal of Korean Society of Transportation
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• v.30 no.2
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• pp.29-42
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• 2012

Recently, traffic congestion has become serious due to increase of private car usages. Carsharing or other innovative public transportation systems were developed to alleviate traffic congestion and carbon emissions. These measures can make the traffic environment more comfortable, and efficient. Cloud Transportation System (CTS) is a recent carsharing model. User can rent an electronic vehicles with various traffic information through the CTS. In this study, a concept, vision and scenarios of CTS are introduced. And, authors analyzed the location of CTS rental stations and estimated CTS demands. Firstly, we analyze the number of the population, employees, students and traffic volume in study areas. Secondly, the frequency and utilization time are examined. Demand for CTS in each traffic zone was estimated. Lastly, the CTS rental station location is determined based on the analyzed data of the study areas. Evaluation standard of the determined location includes accessibility and density of population. And, the number of vehicles and that of parking zone at the rental station are estimated. The result suggests that Haewoondae Square parking lot would be assigned 11 vehicles and 14.23 parking spaces and that Dongbac parking lot be assigned 7.9 vehicles and 10.29 parking spaces. Further study requires additional real-time data for CTS to increase accuracy of the demand estimation. And network design would be developed for redistribution of vehicles.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.1
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• pp.82-96
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• 2024

While analyzing traffic flow, speed, traffic volume, and density are important macroscopic indicators, and acceleration and spacing are the important microscopic indicators. The speed and traffic volume can be collected with the currently installed traffic information collection devices. However, acceleration and spacing data are necessary for safety and autonomous driving but cannot be collected using the current traffic information collection devices. 'You Look Only Once'(YOLO), an object recognition technique, has excellent accuracy and real-time performance and is used in various fields, including the transportation field. In this study, to measure acceleration and spacing using YOLO, we developed a model that measures acceleration and spacing through changes in vehicle speed at each interval and the differences in the travel time between vehicles by setting the measurement intervals closely. It was confirmed that the range of acceleration and spacing is different depending on the traffic characteristics of each point, and a comparative analysis was performed according to the reference distance and screen angle to secure the measurement rate. The measurement interval was 20m, and the closer the angle was to a right angle, the higher the measurement rate. These results will contribute to the analysis of safety by intersection and the domestic vehicle behavior model.

• Journal of Environmental Health Sciences
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• v.50 no.3
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• pp.191-200
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• 2024

Background: Busan is a rapidly industrializing city with many mixed residential and industrial areas. Fine dust emissions from mobile pollution sources such as ships and vehicles are particularly high in Busan. Objectives: This study analyzed the spatial distribution of air pollutants over the past three years and identified the impact of air pollutants through mobile source data in Busan. Methods: We obtained air pollutant data on fine particulate matter (PM₁₀), ultrafine particulate matter (PM_2.5), nitrogen dioxide (NO₂), sulfurous acid gas (SO₂), and ozone (O₃) for the last three years (source: airkorea.or.kr) and analyzed the spatial distribution using SAS 9.4 and Surfer 23. For the mobile pollutant data, we used CCTV data from major intersections in Busan to identify truck and car traffic, and visualized traffic density with QGIS. Results: The analysis of the concentration of air pollutants over three years (2020~2022) showed that all were lower than the annual environmental standards with the exception of PM_2.5. PM₁₀ and PM_2.5 were found to be highly concentrated in the western part of the area, while NO₂ was high in the port area of Busan and SO₂ was high in the western part of the area and near the new port of Busan. In the case of O₃, it was high in the eastern part of the city. The traffic volume of freight vehicles by intersection was concentrated in the West Busan area, and the traffic volume for all cars was also confirmed to be concentrated at "Mandeok Intersection" located in the West Busan area. Conclusions: This study was conducted to determine the relationship between air pollutants emitted from motor vehicles and the distribution of air pollutants in Busan. The spatial distribution of PM₁₀ and PM_2.5 correlates with traffic volume, while high concentrations of SO₂ and NO₂ near the port are associated with ship emissions.