• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.17-22
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• 2019

Network attack analysis and visualization methods using network traffic session data detect network anomalies by visualizing the sender's and receiver's IP addresses and the relationship between them. The traffic flow is a critical feature in detecting anomalies, but simply visualizing the source and destination IP addresses symmetrically from up-down or left-right would become a problematic factor for the analysis. Also, there is a risk of losing timely security situation when designing a visualization interface without considering the temporal characteristics of time-series traffic sessions. In this paper, we propose a visualization interface and analysis method that visualizes time-series traffic data by using the radial axis, divide IP addresses into network and host portions which then projects on the cylindrical coordinate system that could effectively monitor network attacks. The proposed method has the advantage of intuitively recognizing network attacks and identifying attack activity over time.

• Journal of Korean Society of Transportation
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• v.27 no.2
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• pp.133-144
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• 2009

In Korea, the ITS project has been progressed to improve traffic mobility and safety. Further, it is to relieve traffic jam by supply real time travel information for drivers and to promote traffic convenience and safety. It is important that the traffic information is provided accurately. This study was conducted outlier elimination and missing data adjustment to improve accuracy of raw data. A method for raise reliability of travel time prediction information was presented. We developed Historical Profile model and adjustment formula to reflect quality of interrupted flow. We predicted travel time by developed Historical Profile model and adjustment formula and verified by comparison between developed model and existing model such as Neural Network model and Kalman Filter model. The results of comparative analysis clarified that developed model and Karlman Filter model similarity predicted in general situation but developed model was more accurate than other models in incident situation.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.169-181
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• 2017

As vehicle supply rate increases, traffic jam-related problems emerge and sharing transportation including carpool, centered on the advanced countries, becomes a major interest. This study aims to analyze benefit generated by carpool during the rush hours of medium and long distance travel, focused on the workers of public Agencies relocated to innovation cities. In order to compute benefit, carpool demand of relocated public Agencies was estimated and travel speed was estimated according to reduced traffic volume through carpool adoption using a traffic flow model. The benefit were computed dividing them into direct benefit and indirect benefit. As a result, 23billion KRW and 56.5billion KRW were annually revealed to be generated in terms of direct benefit and indirect benefit. The study result is expected to be used as part of basic research to adopt carpool for future traffic demand management.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.4
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• pp.20-29
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• 2014

Density is applied both three major macroscopic traffic variables (traffic volume, speed, and density) and two measures of effectiveness (MOE) for level of service (LOS) on highway (density and V/C). Especially, it is known for the most accurate MOE on evaluating the LOS of highway. Despite such importance, there is a lack of study on density relatively than other variables for its difficulty of measurement. Existing density estimation methods have some limitations such as density values of same traffic flow vary with collecting time. In this study, we researched actual density measuring method with panoramic image, after each CCTV images in the Sapaesan Tunnel on Seoul Ring Expressway are matched into one panoramic image. Analysis through the Central Limit Theorem shows that density of 24 1 km-images, which means 24 second, applies traffic situation well. That is to say that reasonable density value regardless of collecting time, and practical density which represents actual traffic flow can be taken in case of measuring density by suggested collecting cycle.

• International Journal of Highway Engineering
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• v.9 no.4
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• pp.21-32
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• 2007

The linear traffic model(Vertical queueing model) that is adopted widely in traffic flow estimation assumes that all vehicles have the identical motion before joining a queue at the stop-line. Thus, a queue is supposed to form vertically not horizontally. Due to the simplicity of this model, the departure time of the leading vehicle is assumed to coincide with the start of effective green time. Thus, the delay estimates given by the Vertical queueing model is not always realistic. This paper explores a microscopic traffic model(a Kinematic Car-following model at Signalised intersections: a KCS traffic model) based on the one dimensional Kinematic equations in physics. A comparative evaluation in delay and sensitivity of delay difference between the KCS traffic model and the previously known Vertical queueing model is presented. The results show that the delay estimate in the Vertical queueing model is always greater than or equal to the KCS traffic model; however, the sensitivity of delay in the KCS traffic model is greater than the Vertical queueing model.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.869-875
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• 2019

The service level of the roundabout is estimated through an analytic model using the geometrical characteristics and parameter values obtained from the observations. Although a lot of researches have been conducted on the rotational intersection through an analytical model, the case of variable combinations is enormous, suggesting the range and service level of appropriate traffic volume according to the case study or limited characteristics through simulation. Therefore, in this study, the roundabout analysis model was constructed by using Visual Basic Application to make variable adjustment more easily. The constructed model analyzes traffic conditions according to various situations and analyzes the characteristics of roundabouts. As the result of analysis, the more the ratio of left turn and U-turn, the more the traffic distribution of each approached road was biased to one side, the limit traffic volume of the roundabout decreased and congestion appeared quickly. In particular, the more uneven the distribution of traffic was, the less the Saturation traffic volume was affected by the turnover rate.

• 한국ITS학회:학술대회논문집
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• 2010.05a
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• pp.126-131
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• 2010

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.171-171
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• 2004

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.2
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• pp.263-272
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• 2019

This study demonstrates the applicability of the FLO-2D for the influence analysis of the debris flow on expressway. To do this, the behavior of debris flow on the expressway was reproduced by applying the FLO-2D to actual generated debris flow. The study area is a part of the Deokyusan Service Area on the Daejon-Jinju Expressway, where traffic was blocked for 24 hours due to the debris flow in August 2005. Geographical analysis with GIS, hydrological analysis with HEC-HMS, and estimation of the amount of debris flow were carried out using field survey and soil property test data. Then, the optimum parameter combination of FLO-2D was selected through the parameter sensitivity analysis, and the behavior analysis of debris flow on expressway was applied. The comparison of the predictions with the observations shows the availability of FLO-2D for the behavior analysis of debris flow on the expressway.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.5
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• pp.37-45
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• 2004

As Internet technologies are mature, many new applications that are different characteristics are emerging. Recently we see wide use of P2P(Peer to Peer) applications of which traffic shows different statistical characteristics compared with traditional application such as web(HTTP) and FTP(File Transfer Protocol). In this paper, we measured subscriber network of KT(Korea Telecom) to analyze P2P traffic characteristics. We show flow characteristics of measured traffic. We also estimate Hurst parameter of P2P traffic and compare self-similarity with web traffic. Analysis results indicate that P2P traffic is much bustier than web traffic and makes both upstream traffic and downstream traffic be symmetric. To predict parameters related QoS such as packet loss and delays we model P2P traffic using two self-similar traffic models and predict both loss probability and mm delay then compare their accuracies. With simulation we show that the self-similar traffic models we derive predict the performance of P2P traffic accurately and thus when we design a network or evaluate its performance, we can use the P2P traffic model as reference input traffic.