• Journal of Information Processing Systems
• /
• v.19 no.1
• /
• pp.130-138
• /
• 2023

The traffic flow in an urban area is affected by the date, weather, and regional traffic flow. The existing methods are weak to model the dynamic road network features, which results in inadequate long-term prediction performance. To solve the problems regarding insufficient capacity for dynamic modeling of road network structures and insufficient mining of dynamic spatio-temporal features. In this study, we propose a novel traffic flow prediction framework called shared spatio-temporal attention convolution optimization network (SSTACON). The shared spatio-temporal attention convolution layer shares a spatio-temporal attention structure, that is designed to extract dynamic spatio-temporal features from historical traffic conditions. Subsequently, the graph optimization module is used to model the dynamic road network structure. The experimental evaluation conducted on two datasets shows that the proposed method outperforms state-of-the-art methods at all time intervals.

• Journal of KIISE:Information Networking
• /
• v.31 no.1
• /
• pp.70-80
• /
• 2004

In order to reduce the increasing packet loss rates caused by an exponential increase in network traffic, the IETF(Internet Engineering Task Force) is considering the deployment of active queue management techniques such as RED(Random Early Detection). But, RED configuration has been a problem since its first proposal. This problem is that proposed configuration is only good for the particular traffic conditions studied, but may have detrimental effects if used in other conditions. While active queue management in routers and gateways can potentially reduce packet loss rates in the Internet, this paper has demonstrated the inherent weakness of current techniques and shows that they are unstable for tile various traffic conditions. The inherent problem with these queue management algorithms is that they all use static parameter setting. In this paper, in order to solve this problem, a new active queue management algorithm called SQM(Stabilized Queue Management) is proposed. This paper shows that it is easy to parameterize SQM algorithm to perform well under different congestion scenarios. This algorithm can effectively reduce packet loss while maintaining high link utilizations and is good for the various traffic conditions.

• Journal of Korean Society of Transportation
• /
• v.32 no.5
• /
• pp.497-502
• /
• 2014

As ground air traffic control at the airport is one of the most important tasks in air transport, attention to the development of a related simulator has expanded all around the world. For this reason, this research describes the characteristics and advantages of this advanced aerodrome traffic control simulator, developed in South Korea, as well as its linkage with A-SMGCS, which is planned to be developed in the future. One of the characteristics of this simulator is that it is possible to train an air traffic controller independently, especially under various conditions such as in different weathers and normal or abnormal circumstances. Therefore, this aerodrome traffic control simulator, through the comprehensive training under various conditions, will contribute to aviation safety and airport capacity enhancement training.

• Journal of Korean Society of Transportation
• /
• v.32 no.5
• /
• pp.522-530
• /
• 2014

Spatio-temporal congestion evolution pattern can be reproduced using the VDS(Vehicle Detection System) historic speed dataset in the TMC(Traffic Management Center)s. Such dataset provides a pool of spatio-temporally experienced traffic conditions. Traffic flow pattern is known as spatio-temporally recurred, and even non-recurrent congestion caused by incidents has patterns according to the incident conditions. These imply that the information should be useful for traffic prediction and traffic management. Traffic flow predictions are generally performed using black-box approaches such as neural network, genetic algorithm, and etc. Black-box approaches are not designed to provide an explanation of their modeling and reasoning process and not to estimate the benefits and the risks of the implementation of such a solution. TMCs are reluctant to employ the black-box approaches even though there are numerous valuable articles. This research proposes a more readily understandable and intuitively appealing data-driven approach and developes an algorithm for identifying congestion patterns for recurrent and non-recurrent congestion management and information provision.

• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.311-316
• /
• 2005

The power saving mechanism of IEEE 802.16e operates in two modes; awake mode and sleep mode. While the user terminal transmits and receives packets in awake mode, it sleeps for a given interval to save the power consumption in sleep mode. The IEEE 802.16e specifies that the user terminal increases the sleep interval exponentially unless it has to wake up. In this paper, we analyze the performance of IEEE 802.16e power saving mechanism by considering down link traffic conditions. With the extensive simulations, we observe the trade-off between the power saving performance and the average packet delay. In addition, we observe that various performance parameters of IEEE 802.16e power saving mechanism are affected by the traffic patterns.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2000.11a
• /
• pp.44-48
• /
• 2000

In this study was modify the PRMA for supporting various types of traffic classes such as CBR, VBR, ABR and UBR. For uplink, we use reservation slots and so the performance will not degrade in case of over load conditions. For downlink broadcasting slots for informing the status of slot reservations are used so the high priority priority terminal can preempt. And we use almost same size buffer as the frame size. So we can dynamically deal with, the traffic changes of VBR terminals. It makes easy for the terminals to reserve supplementary slots. Each terminal is reallocated by the priority of traffic classes and so we can easily select the dropping packets in case of overload conditions. As a result, using our scheme, we can get high channel efficiency and get low packet dropping ratio and delay.

• International Journal of Internet, Broadcasting and Communication
• /
• v.6 no.2
• /
• pp.20-24
• /
• 2014

These days the large-scale car accidents have often been occurred by overspeeding in disregard of sharp curve, foggy and freezing regions. This paper has proposed the algorithm to calculate the safety speed in real time that can protect the car accidents under these weather and road conditions using Fuzzy reasoning theory. Under raining and snowing, drivers have to slow down the traffic safety speed by 1/3 of the traffic safety speed indicated on the existing speed sign plate based on their decision. So it is difficult to calculate and then observe the safety speed. This paper has performed the simulation that provides the deivers with the optimal safety speed considering the road and weather conditions in real time to improve these problems. We have proved this method can improve more 25% than the existing one.

• Journal of Korean Society of Transportation
• /
• v.5 no.1
• /
• pp.3-23
• /
• 1987

Traffic signal control problems in urban street networks are formulated in two ways. In the formulations network flows are assumed to satisfy the user route choice criterion. the first formulation which is called implicit substiuation incorporates user route behavior implicitly in the objective function by recognizing the dependence of the link flows on the signal variables. On the other hands, the second one which is called 'penalty formulation' consists in expressing the route choice conditions in the form of a single nonlinear constraint. Approximate solution algorithm for each of the formulations was investigated in detail and computer codes were written to examine key aspects of each algorithm. A test was done on a network which is small in size but sufficiently complex in representing real-world traffic conditions and the test result shows that both algorithms produce converged solutions. It is recommended, however, that further studies should be done in order to compare the performance of each algorithm more in depth.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.32A no.3
• /
• pp.411-417
• /
• 1995

Packet switching is an important aspect of ISDN. In the TDX-10 switching system, which is being developed as an ISDN exchange in Korea, the packet switching function is implemented on the basis of Case B scenario of X.31. After implementing the packet switching function the performance test must be executed to check whether the design objectives of performance are satisfied or not. However, it is not easy to set up test environment for performance measurement under full load conditions. This paper presents the design of the traffic generator which enables us to do performance test of the TDX-10 packet handler under full load conditions. To generate packet traffic we change only software programs without any change of the hardware system of the packet handler.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.19 no.4
• /
• pp.425-432
• /
• 2009

Recently, reduction of road traffic noise in residential buildings has become one of the most important subjects. To reduce the road traffic noise, noise impact assessment by the road traffic prediction model is required before building construction. For reasonable road traffic noise prediction, it is required to analysis of various factors in road traffic prediction models. This paper was studied the road traffic noise propagation factors such as distance from road to building, receiver height, alignment angle of building and reflection coefficient of the building facade by two calculation models, RLS-90 and CRTN. The result showed that noise reduction was generally higher at bottom stories by ground absorption effect. The reflection coefficient of the building facade was affect of additional sound pressure level by facade reflecting. And alignment angle of building at $90^{\circ}$ was performed effective noise reduction better than $0^{\circ}$.