• Journal of Korean Society of Transportation
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• v.32 no.4
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• pp.369-379
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• 2014

The Statistical regression model has been used to construct crash prediction models, despite its limitations in assuming data distribution and functional form. In response to the limitations associated with the statistical regression models, a few studies based on non-parametric methods such as neural networks have been proposed to develop crash prediction models. However, these models have a major limitation in that they work as black boxes, and therefore cannot be directly used to identify the relationships between crash frequency and crash factors. A genetic programming model can find a solution to a problem without any specified assumptions and remove the black box effect. Hence, this paper investigates the application of the genetic programming technique to develope the crash prediction model. The data collected from the Gyeongbu expressway during the past three years (2010-2012), were separated into straight and curve sections. The random forest technique was applied to select the important variables that affect crash occurrence. The genetic programming model was developed based on the variables that were selected by the random forest. To test the goodness of fit of the genetic programming model, the RMSE of each model was compared to that of the negative binomial regression model. The test results indicate that the goodness of fit of the genetic programming models is superior to that of the negative binomial models.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.2
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• pp.13-23
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• 2016

Many traffic centers are highly hesitant in employing existing Automatic Incident Detection Algorithms due to high false alarm rate, low detection rate, and enormous effort taken in maintaining algorithm parameters, together with complex algorithm structure and filtering/smoothing process. Concerns grow over the situation particularly in Freeway Incident Management Area This study proposes a new algorithm and introduces a novel concept, the Displaced Flow Index (DiFI) which is similar to a product of relative speed and relative occupancy for every execution period. The algorithm structure is very simple, also easy to understand with minimum parameters, and could use raw data without any additional pre-processing. To evaluate the performance of the DiFI algorithm, validation test on the algorithm has been conducted using detector data taken from Naebu Expressway in Seoul and following transferability tests with Gyeongbu Expressway detector data. Performance test has utilized many indices such as DR, FAR, MTTD (Mean Time To Detect), CR (Classification Rate), CI (Composite Index) and PI (Performance Index). It was found that the DR is up to 100%, the MTTD is a little over 1.0 minutes, and the FAR is as low as 2.99%. This newly designed algorithm seems promising and outperformed SAO and most popular AIDAs such as APID and DELOS, and showed the best performance in every category.

• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.75-82
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• 2005

To relieve congestion in the current system of intercity transportation, the Korea decided in 1990 to construct a high-speed railroad between Seoul and Busan and it is now in operation. This new mode of transportation significantly cut travel time between major cities and a trip from Seoul to the southeastern port of Busan. Since the KTX opening, average daily passenger numbers on both the Gyeongbu and Honam lines have increased about 1.3 fold over 2003 levels. As of December 2004, the KTX trains are carrying about 81,000 people a day. On KTX routes, the daily number of airline passengers dropped. Express long-distance bus traffic also dropped by 20% to 30%, while that on short-distance routes (100km or less) increased by about 20%. These figures clearly indicate that the Korean transportation network is becoming railroad-centric. However, the number of KTX passengers is fewer than anticipated possibly due to the Korean economic downturn and the operation of the KTX will leave many existing Saemaul and Mugunghwa train sets idle, which will be put into operation for areas, not covered by the KTX. When all the existing major lines have been electrified, more high-speed rail services will be phased in using direct connections to maximize operational efficiency. And also, the dual management by KTX and conventional rail will be regarded as the promotion of the benefit of the public.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.5
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• pp.375-384
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• 2021

The development of the European Railway Traffic Management System (ERTMS) began in 1989 as part of the European Union policy to establish a unified and interoperable railway route in Europe. It is a trend that ERTMS/ETCS(European Train Control System) is becoming an international standard in the railway signaling system. As the solution to this situation, the domestic railway signaling field is also at a time when it is more necessary to develop the technology of the train control system considering interoperability. The European Railway Agency (ERA) has proposed B3R2 (Baseline 3 Release 2) for new ETCS-equipped trains after 2020.12.31. In Korea, Baseline 2.2.0 to 2.3.0d on Gyeongbu Line, Honam Line, Jeolla Line, and Gyeongchun Line was installed and now is under operating. As the Baseline upgrade continues, technical considerations and economic considerations are an occurring trend. In this paper, we analyzed the main functions and compatibility of the currently distributed European standard ERTMS/ETCS Baseline 3 and presented a plan to apply the domestic KTCS(Korean Train Control System) Baseline in the near future.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.4
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• pp.16-30
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• 2019

In this study, we calculated the driving duration of individual vehicles according to the availability of rest facility on highway, and suggested indicators indicating the potential risk of accidents caused by long-term driving with weights based on the number of vehicles by driving duration of individual links. Based on this, the methodology for estimating the appropriate location of the highway rest facility considering the driving duration of individual vehicles was presented. Using the DSRC individual vehicle data collected from the highways, the appropriate location of the rest facility was calculated by considering the driving duration by classifying weekdays and weekends for the Gyeongbu Expressway. The results showed that the weekly and weekend high risk indicators were different. In the case of weekdays, the risk indicators of Gimchun JC to Kumho JC for Busan were high, while for weekends, the risk indicators of Ansung JC to Dongtan JC for Seoul and Ansung IC to Bukchunan IC for Busan were high. This study has great significance in that it provides a framework for detailed analysis of link units by using non-aggregated data of individual vehicle units. In addition, it is significant that the reasonable driving duration reflecting the behavior of individual vehicles was calculated by analyzing the use of rest facilities.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6D
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• pp.569-575
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• 2010

The occupancy based O/D is essential for measuring efficiency of various transportation policies like HOV/HOT lane, ramp metering, and public parking station. There has been many studies on occupancy survey methodology and O/D estimation using TCS (Toll Collection System) data separately. The occupancy O/D estimation methodology using TCS data has not been attempted thus far. An overall process from data collection stage to the occupancy O/D estimation stage has been suggested. Field survey was performed at the northbound Seoul toll station of Gyeongbu Expressway by each 2 hours of AM peak, PM non-peak, PM peak, midnight periods on a day. The process of matching the TCS data and field survey data classified by tollbooth ID, car type/mode, and arrival time was also performed. One typical output of the results showed that the ratio of single occupancy vehicles bounding for Seoul during the AM peak amounted to 60%. With the key output of this study and the specific O/D estimation methodology suggested, the whole centroid-to-centroid occupancy O/D of the country could be available, and then various applications in which the occupancy information is required could be possible.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.2
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• pp.61-68
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• 2024

The majority of high-speed railway bridges along the domestic Gyeongbu and Honam lines feature a PSC-box type structure with a span length ranging from 35 to 40m, which typically exhibits a first bending natural frequency of approximately 4 to 5Hz. When KTX high-speed trains transverse these bridges at speeds ranging from 290 to 310km/h, the vibration induced by the trains approaches the first bending natural frequency of the bridge. Furthermore, with the upcoming operation of a EMU-320 high-speed train and the anticipated increase in the speeds of these high-speed trains, there is a need to analyze the dynamic response of high-speed railway bridges. For this, based on measured responses from actual railway bridges, a numerical model was constructed using a numerical model updating technique. The dynamic response of the updated numerical model exhibited a strong agreement with the measured response from the actual railway bridges. Subsequently, this updated model was utilized to analyze the dynamic response characteristics of the bridges when KTX and EMU-320 trains operate at increased speeds. The maximum vertical displacement and acceleration at the mid-span of the bridges were also compared to those specified in the railway design standard with the increasing speed of KTX and EMU-320.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.161-172
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• 2012

The purpose of this study is to classify, evaluate and grade the existing highway tunnels to increase landscape and natural statistics keeping the structural safety about tunnel gates area and induce the ones that will be constructed in the future by drawing the improvements and restoring the techniques as an environment-friendly. To examine the types of tunnel gate area, total 54 tunnels were investigated by selecting Gyeongbu Expressway, Yeongdong Expressway, and Jungang Expressway. Tunnel entrances and exit ports were classified as a Wall-closed type and Protruding type, which is based on tunnel gate type. Vegetation Landscape types were classified as Multilayer-Same as the surrounding landscape_(MS), Multilayer-Difference of surrounding landscape_(MD), Single layer-Same as the surrounding landscape_(SS), Single layer-Difference of surrounding landscape_(SD), and a Desolate type which based on vegetation layers and environment-friendly. Potential vegetation recovery was identified based on the structural stability and revegetation potential of the tunnel. The factors include the structural stability of the slope height and slope gradient were selected. Revegetation potential was identified as a growth potential. This factor was used in the step to classify vegetation recovery potential of a tunnel. The result, which investigated the types of tunnel entrances and exit parts has found that the most typical in 33 places was a Wall closed type with 61.1% of the total ones. The case of vegetation landscape types was created but different from the ones surrounding it with 85.2% of the total ones. It is judged that the currently constructed vegetation of tunnel entrance and exit parts had put convenience on the safety and management before landscape consideration. In addition, tunnel entrance and exit parts with excellent potential for vegetation recovery were all Protruding type. In addition, it is judged that slope stability can easily obtain growth. Therefore, entrance and exist of the highway tunnels, which will be constructed in the future, should reflect location and the result of the natural and ecological survey in design by performing it in advance and their types, which minimize the damage area range, should be applied to the local characteristics suitably. In addition, the ecologically healthy tunnel construction should be done by introducing active vegetation recovery techniques based on its safety.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.161-175
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• 2024

Aggregate typically refers to sand and gravel formed by the transportation of rocks in rivers or artificially crushed, constituting a core resource in the construction industry. Gyeongsangbuk-do, the largest administrative area in South Korea, produces various sources of gravel, including forest, land (excluding other sources), river, and crushed stone. As of 2022, it has extracted approximately 6.96 million cubic meters of aggregate, with permitted production totaling around 4.07 million cubic meters and reported production of about 2.88 million cubic meters. The aggregate demand in Gyeongsangbuk-do is estimated to be 12.39 million cubic meters according to the estimation method in Ready-Mix Concrete. From the supply perspective, about 120 extraction sites are operational, with most municipalities maintaining an appropriate balance between aggregate demand and supply. However, in some areas, there is inbound and outbound transportation of aggregate to neighboring regions. Regions with significant inbound and outbound aggregate transportation in Gyeongsangbuk-do are areas connected to Daegu Metropolitan City and Pohang City along the Gyeongbu rail line, showing a high correlation with population distribution. Gyeongsangbuk-do faces challenges such as population decline, aging rural areas, and insufficient balanced regional development. Analysis using GIS reveals these trends in gravel demand and supply. Currently in this study, Gyeongsangbuk-do meets its demand for aggregate through the supply of various aggregate sources, maintaining stable aggregate procurement. River and terrestrial aggregates may be sustained as short-term supply strategies due to the difficulty of longterm development. Considering the reliance on raw material supply for selective crushing, it suggests the need for raw material management to maintain stability. Gyeongsangbuk-do highlights quarries in the forest as an important resource for sustainable aggregate supply, advocating for the development of large-scale aggregate quarries as a long-term alternative. These research findings are expected to provide valuable insights for formulating strategies for sustainable management and stable utilization of aggregate resources.