• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.93-104
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• 2002

The purpose of this study was to develop a improved high-order continuum model among macroscopic traffic flow models. This study was mainly performed for uninterrupted flow. In the first step, the proposed model described traffic flow at dropped lane. (no exits) It was possible to describe the traffic flow during short-term considering lane change. The proposed model was based on Payne's model. Our model was newly applied to uninterrupted traffic flow in consideration of geometry condition and driver behavior. It is possible to establish efficient control strategies, simulation and assess the effects of geometric improvements using this model. This model was simulated with field data for the actual adaption. The results of the model tests, traffic volume and density is suitably represented. we think that the results in the article can be led to predicting the situation in the near future.

• Journal of KIISE:Information Networking
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• v.37 no.1
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• pp.27-34
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• 2010

In this paper, we examine a long-range dependence in an active measurement of a network traffic which has been a well known characteristic from analyses of a passive network traffic measurement. To this end, we utilize RTT(Round Trip Time), which is a typical active measurement measured by PingER project, and perform a relevant analysis to a time series of both RTT and its volatilities. The RTT time series exhibits a long-range dependence or a 1/f noise. The volatilities, defined as a higher-order variation, follow a log-normal distribution. Furthermore, volatilities show a long-range dependence in relatively short time intervals, and a long-range dependence and/or 1/f noise in long time intervals. From this study, we find that the long-range dependence is a characteristic of not only a passive traffic measurement but also an active measurement of network traffic such as RTT. From these findings, we can infer that the long-range dependence is a characteristic of network traffic independent of a type of measurements. In particular, an active measurement exhibits a 1/f noise which cannot be usually found in a passive measurement.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.40-48
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• 2006

In this paper, we propose the EPTS(Emergency vehicle Priority Transit system) for a rapid drive or emergency vehicles at the crossroads. The EPTS is one part of real-time traffic management system in the advanced traffic management system. The EPTS needs the connection or a traffic control system and a DSRC system. It can be applied to the real traffic situation considered with other traffic elements. As the result it is possible for the EPTS to nonstop drive because it induces an efficient drive of emergency vehicles. It is also relatively safe at the crossroad, it is expected that the EPTS is suitable for a telematics service which values efficiency above everything else.

• The KIPS Transactions:PartC
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• v.14C no.1 s.111
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• pp.45-54
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• 2007

As one of the most threatening attacks, DDoS attack makes distributed multiple agents consume some critical resources at the target within the short time, thus the extent and scope of damage is serious. Against the problems, the existing defenses focus on detection, traceback (identification), and filtering. Especially, in the hierarchical networks, the traffic congestion of a specific node could incur the normal traffic congestion of overall lower nodes, and also block the control traffic for notifying the attack detection and identifying the attack agents. In this paper, we introduce a DDoS attack tolerant network structure using a hierarchical overlay for hierarchical networks, which can convey the control traffic for defense such as the notification for attack detection and identification, and detour the normal traffic before getting rid of attack agents. Lastly, we analyze the overhead of overlay construction, the possibility of speedy detection notification, and the extent of normal traffic transmission in the attack case through simulation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.295-302
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• 2018

Since the history of the South Korea roundabouts is short, there is a possibility that drivers' awareness for the roundabouts (rules of the road, definition, location, etc.) is low, which may affect the compliance with traffic rules. Based on this assumption, the objective of this study is to analyze the relationship between the awareness and the compliance of traffic rules for roundabouts using a structural equation modeling (SEM). To carry out this objective, an online survey was conducted for 526 drivers, who reside in Goyang, Korea, and an SEM was estimated based on the survey data. As a result, it is concluded that awareness of roundabout has a positive impact on the compliance of traffic rules. Additionally, the compliance is found to show a positive relationship with driving experience. Based on the analysis results, an affective approach through soft measures such as awareness campaigns and educations is recommended to effectively address and mitigate the negative issues induced by roundabouts.

• Journal of Korean Society of Transportation
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• v.25 no.1 s.94
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• pp.121-132
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• 2007

Up to now Permanent traffic volumes have been counted by Automatic Vehicle Classification (AVC) on National Highways. When counted data have missing items or errors, the data must be revised to stay statistically reliable This study was carried out to estimate correct data based on outoregression and seasonal AutoRegressive Integrated Moving Average (ARIMA). As a result of verification through seasonal ARIMA, the longer the missed period is, the greater the error. Autoregression results in better verification results than seasonal ARIMA. Traffic data is affected by the present state mote than past patterns. However. autoregression can be applied only to the cases where data include similar neighborhood patterns and even in this case. the data cannot be corrected when data are missing due to low qualify or errors Therefore, these data shoo)d be corrected using past patterns and seasonal ARIMA when the missing data occurs in short periods.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.203-208
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• 2011

Traffic demand is continuously increasing due to the development of urban areas in Korea. To cope with this, many efforts have been done including constructions of new roadways and increasing the number of lanes of the existing roadways. Those efforts, however, have been performed for only a short segment of target links having similar traffic characteristics. As a result, most urban cities experience bottle-neck phenomena which lead decreasing flow speed and increasing possibilities of accidents. Thus, this study aims to analyze problems of bottle-neck phenomena and effects of balancing number of lanes along the same corridor having similar traffic characteristics. For this, Route 32 passing the city of Daejeon in Korea has been selected as a case study, and a micro-simulation tool, VISSIM, has been adopted for the analysis. The results show that balanced number of lanes along the same corridor with similar traffic characteristics can increase flow speeds and enhance safety.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.1
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• pp.1-14
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• 2013

Annual average daily traffic (AADT) serves the important basic data in transportation sector. Despite of its importance, AADT is estimated through permanent traffic counts (PTC) at limited locations because of constraints in budget and so on. At most of locations, AADT is estimated using short-term traffic counts (STC). Though many studies have been carried out at home and abroad in an effort to enhance the accuracy of AADT estimate, the method to simplify average STC data has been adopted because of application difficulty. A typical model for estimating AADT is an adjustment factor application model which applies the monthly or weekly adjustment factors at PTC points (or group) with similar traffic pattern. But this model has the limit in determining the PTC points (or group) with similar traffic pattern with STC. Because STC represents usually 24-hour or 48-hour data, it's difficult to forecast a 365-day traffic variation. In order to improve the accuracy of traffic volume prediction, this study used the geostatistical approach called co-kriging and according to their reports. To compare results, using 3 methods : using adjustment factor in same section(method 1), using grouping method to apply adjustment factor(method 2), cokriging model using previous year's traffic data which is in a high spatial correlation with traffic volume data as a secondary variable. This study deals with estimating AADT considering time and space so AADT estimation is more reliable comparing other research.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.4
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• pp.44-57
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• 2019

Various studies have been conducted to solve traffic congestions in many metropolitan cities through accurate traffic flow prediction. Most studies are based on the assumption that past traffic patterns repeat in the future. Models based on such an assumption fall short in case irregular traffic patterns abruptly occur. Instead, the approaches such as predicting traffic pattern through big data analytics and artificial intelligence have emerged. Specifically, deep learning algorithms such as RNN have been prevalent for tackling the problems of predicting temporal traffic flow as a time series. However, these algorithms do not perform well in terms of long-term prediction. In this paper, we take into account various external factors that may affect the traffic flows. We model the correlation between the multi-dimensional context information with temporal traffic speed pattern using deep neural networks. Our model trained with the traffic data from TOPIS system by Seoul, Korea can predict traffic speed on a specific date with the accuracy reaching nearly 90%. We expect that the accuracy can be improved further by taking into account additional factors such as accidents and constructions for the prediction.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.4
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• pp.107-117
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• 2008

OBE(On Board Equipment) of IR(Infrared)/RF(Radio Frequence)-DSRC(Dedicated Short Range Communication) are set up 1.25 million cars because Korea Highway Cooperation supplied in HiPass(Domestic Electronic Toll Collection System). But this DSRC system has strength and weakness of service for BIS(Bus Information System) or UTIS(Urban Traffic Information System) because BIS and UTIS are required vary high communication's performance and management. In this paper, Efficiency of IR/RF-DSRC is analyzed performance of MAC(Medium Access Control) by computer simulation for services of BIS or UTIS, so Suggested to be commensurated with medium of there service. Specially, DSRC is needed high mobility and throughput in the vary short communication range, so Analysed the transmission rate of data in each communication medium over the specific character of the MAC frame.