• Journal of Korean Society of Transportation
• /
• 제20권1호
• /
• pp.101-110
• /
• 2002

This study first explains general features of traffic assignment models and network loading methods, and investigates the relationship between them. Then it introduces a dynamic network loading method, which accounts far time variable additionally. First of all, this study suggests that it is important to consider some requirements for the dynamic network loading, such as causality, FIFO(First-In-First-Out) discipline, the flow propagation, and the flow conservation. The details of dynamic network loafing methods are explained in the form of algorithm, and numerical examples are shown in the test network by adopting deterministic queuing model for a link Performance function.

• Korean Management Science Review
• /
• 제27권3호
• /
• pp.1-14
• /
• 2010

In this paper we study the access network design problem in Universal Mobile Telecommunication Systems (UMTS) networks. Given the location of radio base stations (node-Bs), their traffic demands, and the candidate facility centers for locating radio network controllers (RNCs), the problem is to determine the configuration of access network, including the number and location of facility centers, the number of RNCs in each facility center, and the links between RNCs and node-Bs, with the objective being to design such a network at the minimum cost. We provide a mathematical formulation of the problem with constraints on RNC and node-B capacities, along with a lower bounding method. We develop a heuristic algorithm with two different initial solution methods designed to strengthen the solution quality. The computational efficacy of their procedures is then demonstrated on a number of test problems.

• The Journal of the Korea institute of electronic communication sciences
• /
• 제12권5호
• /
• pp.805-816
• /
• 2017

Tor is a popular, low-latency open network that offers online anonymity to users by concealing their information from anyone conducting traffic analysis. At the same time, a number of conventional passive and active attacking schemes have been proposed to compromise the anonymity provided by the Tor network. In addition to attacks on the network through traffic analysis, interacting with an unsecured application can reveal a Tor user's IP address. Specific traffic from such applications bypasses Tor proxy settings in the user's machine and forms connections outside the Tor network. This paper presents such applications and shows how they can be used to deanonymize Tor users. Extensive test studies performed in the paper show that applications such as Flash and BitTorrent can reveal the IP addresses of Tor users.

• Journal of KIISE:Computing Practices and Letters
• /
• 제8권3호
• /
• pp.328-335
• /
• 2002

When we want to transfer video streaming data through computer networks, we will have to be allocated a larger bandwidth compared to a general application. In general, it causes a serious network overload inevitably due to the limited bandwidth. In this paper, in order to resolve the problem, we haute taken a method for transmitting video streaming data using RTP and RTCP. With RR(Receiver Report) packet in RTCP we will test it to check whether the traffic in a network has occurred or not. If it happened, we haute tried to reduce the overall network traffic by dynamically changing the quantization factor of the Motion JPEG that is one of the encoding styles in JMF. When the ratio of the average of transmission for each session to the average of overall transmission is greater than 7%, we should adjust the amount of data to be transmitted for each session to reach the session mean values. The experimental results show that the proposed method taken here reduces the overload effectively and therefore improves the efficiency for transmitting video streaming data.

• Journal of KIISE:Information Networking
• /
• 제33권3호
• /
• pp.201-217
• /
• 2006

In this paper, we collected the physical traces from high speed Internet backbone traffic and analyze the various characteristics of the underlying packet traces. Particularly, our work is focused on analyzing the characteristics of an anomalous traffic. It is found that in our data, the anomalous traffic is caused by UDP session traffic and we determined that it was one of the Denial of Service attacks. In this work, we adopted the unsupervised machine learning algorithm to classify the network flows. We apply the k-means clustering algorithm to train the learner. Via the Cramer-Yon-Misses test, we confirmed that the proposed classification method which is able to detect anomalous traffic within 1 second can accurately predict the class of a flow and can be effectively used in determining the anomalous flows.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• 제8권5호
• /
• pp.71-84
• /
• 2009

The communication between the center system and the local controller in the Traffic Signal Controller Specification has been specified by a communication line for the exclusive use and the analog modem serial protocol. Therefore, it can't be adapted in the ITS communication network of the TCP/IP protocol being constructed in the local city. The international and domestic ITS device's communication specification has adapted the DATEX-ASN data exchange technique based on the ethernet communication network. So, this study was performed by the purpose of developing the application communication protocol's standard draft based on the TCP/IP communication protocol for the traffic signal controller, to be able to constitute the traffic signal control system in the ITS communication network. The communication format for 23 items of control, status, and database request etc. which are specified in the standard traffic signal controller was developed by appling the DATEX-ASN data interface procedure and structure which are KS ISO X 14827 Part1, 2, ISO/ DIS 15784 Part-3. To test the developed protocol, the application program for the communication items was developed and according to the test result, the encoding and the decoding transection for all communication items was possible.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• 제31권5B호
• /
• pp.442-448
• /
• 2006

This paper considers a home gateway(HG) that processes VOD services and controls home appliances. This paper proposes a PID algorithm-based adaptive bandwidth control method used in the HG, which guarantees QoS of incoming traffic such as VOD and real-time control data via control of outgoing traffic and have little effects on the CPU computation time. The proposed method is validated via implementation of real test environment.

• Journal of the Korea Society of Computer and Information
• /
• 제10권5호
• /
• pp.123-132
• /
• 2005

In this Paper, we present an improvement of switch node for wavelength multiplex optical network. Currently because of quick increase of internet traffic a big network capacity is demanded. Wavelength multiplex optical network Provides the data transfer of high speed and the transparent characteristic of the data. Therefore optic network configuration is the most powerful technology in the future. It will be able to control the massive traffic from the optical network in order to transmit the multimedia information of very many quantify. Consequently the node where the traffic control is Possible, is demanded. The optical switch node which manages efficiently the multiple wavelength was Proposed. This switch is composed of a optical switch module for switching and a wavelength converter module for wavelength conversion. It will be able to compose the switch fabric without optical/electro or electro/optical conversion using optical MEMS(Micro Electro Mechanical Switches) module. Finally, we present the good test result regarding the operational qualify of the switch fabric and the performance of optical signal from the switch node. The proposed switch node of the optic network will be able to control the massive traffic with all optical.

• Journal of Korean Society of Transportation
• /
• 제28권6호
• /
• pp.75-84
• /
• 2010

Controlled traffic intersection is critical point in terms of transportation network performance, where the most of traffic congestion arises. One of the most important and favorable measure of effectiveness in the signal controlled intersection is approach delay. Although lots of efforts to develop traffic delay estimation models have been made throughout the years, most of them were focusing on homogeneous traffic flow. The purpose of this research is to develop a traffic delay estimation model for traffic flow mixed with bus based on the horizontal shockwave theory. Traffic simulation is performed to test the adaptation level of the model in generic environment. The result shows that the delay increases with increasing bus traffic. Overall model accuracy comparing simulation result is acceptable, that shows the error range around 10 percent.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• 제43권9호
• /
• pp.25-31
• /
• 2006

In this paper, a fatality model of car accident using data mining is proposed with the goal of reducing fatality of traffic accident. The analysis results with a proposed fatality model are utilized to improve a technology and environment for driving. For this, traffic accident data are collected, a data mining algorithm is applied to this data, and then, a fatality model of car accident is developed based on the analysis. The training data as well as test data are utilized to develop the fatality model. The important factors to cause fatality in traffic accidents can be investigated using the model. If these factors are taken into account in traffic policies and driving environment, it is expected that the fatality rate of traffic accident can be reduced hereafter.