• The Transactions of the Korean Institute of Electrical Engineers B
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• 제55권9호
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• pp.485-490
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• 2006

According to the computerization of railway signaling systems, the interface link between the signaling systems has been replaced by the digital communication channel. At the same time, the importance of the communication link is more pronounced than before. In this paper, new Network-based protocol between railway signaling and SCADA (Supervisory Control and Data Acquisition system) has designed and the overview of designed protocol is briefly represented. And also this paper addresses analysis of newly designed train control systems. Fame error rates of the data transmissions are calculated and compared for the two cases that the CTC (Centralized Traffic Control)/SCADA has an extra data transmission error control (CRC16) besides the inherent error control of the Ethernet and that the CTC/SCADA has no extra data transmission error control. With simulation results it has been verified that the additional error control code contributes to lowering the frame error rate. It will be expected to increase the safety, reliability and efficiency of maintenance of the signaling systems by using the designed protocol for railway signaling system.

• Journal of IKEEE
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• 제23권4호
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• pp.1381-1386
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• 2019

As traffic congestion in cities becomes more serious, intelligent traffic control is actively being researched. Reinforcement learning is the most actively used algorithm for traffic signal control, and recently Deep reinforcement learning has attracted attention of researchers. Extended versions of deep reinforcement learning have been emerged as deep reinforcement learning algorithm showed high performance in various fields. However, most of the existing traffic signal control were studied in a single intersection environment, and there is a limitation that the method at a single intersection does not consider the traffic conditions of the entire city. In this paper, we propose a cooperative traffic control at multi-intersection environment. The traffic signal control algorithm is based on a combination of extended versions of deep reinforcement learning and we considers traffic conditions of adjacent intersections. In the experiment, we compare the proposed algorithm with the existing deep reinforcement learning algorithm, and further demonstrate the high performance of our model with and without cooperative method.

• Journal of Institute of Control, Robotics and Systems
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• 제6권8호
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• pp.666-671
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• 2000

With the current advances in optical WDM (Wavelength Division Multiplexing) networking technologies and the increasing demand for network bandwidth the Next Generation Internet is expected to be a network that runs IP(Internet Protocol) directly over WDM-based optical networks. The network control architecture for the IP over WDM networks is different from that of traditional Internet since the underlying WDM devices have more constraints than electronic IP routers such as the lack of optical buffers and wavelength continuity property etc. In this paper we introduce several architectural models for implementing IP over WDM networks and propose an integrated network control framework for the IP over WDM networks. This framework leverages the traffic engineering control architecture for the MPLS (Multi-Protocol Label Switching) networks and is mainly developed for the IP over packet-switched WDM networks. We also report several preliminary simulation results of contention resolution schemes in the packet-switched WDM networks.

• ETRI Journal
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• 제24권1호
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• pp.43-55
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• 2002

This paper proposes a flow-based admission control algorithm through an Asynchronous Transfer Mode (ATM) based Multi-Protocol Label Switching (MPLS) network for multiple service class environments of Integrated Service (IntServ) and Differentiated Service (DiffServ). We propose the Integrated Packet Scheduler to accommodate IntServ and Best Effort traffic through the DiffServ-aware MPLS core network. The numerical results of the proposed algorithm achieve reliable delay-bounded Quality of Service (QoS) performance and reduce the blocking probability of high priority service in the DiffServ model. We show the performance behaviors of IntServ traffic negotiated by end users when their packets are delivered through the DiffServ-aware MPLS core network. We also show that ATM shortcut connections are well tuned with guaranteed QoS service. We validate the proposed method by numerical analysis of its performance in such areas as throughput, end-to-end delay and path utilization.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2000년도 추계종합학술대회
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• pp.288-291
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• 2000

In ATM Network, many algorithms have been proposed for rate-based ABR new control. The object of these Algorithms is to him around from cell loss and to use the unused bandwidth by ABR Traffic. These Algorithms are applied to control ABR Traffic by EFCI and ER switches. In previous paper, we showed the using rate of bandwidth for the characteristic of each algorithm applied these algorithm network In this paper, we will do that to apply these algorithms to a network and to make a graph of characteristic of each algorithm.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제22권50호
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• pp.333-340
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• 1999

An ideal traffic control system should consider simultaneously both route guidance of vehicles and signal policies at intersection of a traffic network. It is known that an iterative procedure gives an optimal route to each vehicle in the network. This paper presents an iterative procedure to find an optimal signal plan for the network. We define the optimal solution as a signal equilibrium. From the definition of signal equilibrium, we prove that the fixed point solution of the iterative procedure is a signal equilibrium, when optimal signal algorithms are implemented at each intersection of the network. A combined model of route guidance and signal planning is also suggested by relating the route guidance procedure and the signal planning procedure into a single loop iterative procedure.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제22권3호
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• pp.580-592
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• 1997

Since an ATM network consists of a number of VPC/VCC requiring various QoS requirements, the end-to-end QoS for each VPC/VCC should be guaranteed. Although many research works on the traffic control are under study to guarantee the QoS, there have been research efforts to reflect the results of network management functions into the traffic control mechanism. To effectively make use of the performance management functions into the VPC/VCC management, threre is a need for the network manager to rapidly retrieve the relevant information. In this research, the mechanism to effectively retrieve the management information using SNMP is suggested. First of all, we construct the MIBs in the agent for the corresponding VPC/VCC. Also, we suggest the way to retrieve MIB with minimum cost. Mathematical analysis shows that the proposed technique has better performance than that using the existing SNMP.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제4권4호
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• pp.745-750
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• 2000

In ATM Network, many algorithms have been proposed for rate-based ABR flow control. The object of these Algorithms is to turn around from cell loss and to use the unused bandwidth by ABR Traffic. These Algorithms are applied to control ABR Traffic by EFCI and ER switches. In previous paper, we showed the using rate of bandwidth for the characteristic of each algorithm applied these algorithm network. In this paper, we will do that to apply these algorithms to a network and to make a graph of characteristic of each algorithm.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.57-60
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• 2005

In this paper, a dynamic priority-based QoS (DPQoS) provision scheme is proposed for the required QoS from one end of the network to the other in wireless mobile networks. The DPQoS model is used to meet diversity multimedia traffic requirements. This model is come up with a framework for the wireless network of which consists of a core-IP network and also a number of wireless access networks. For the true end-to-end QoS, it is required that the core network is able to support the required QoS for the wireless users. This paper shows a solution to optimize the performance for different traffic classes according to the traffic characteristics. The performance of the proposed scheme is evaluated at delay aspects such as delay and throughput.

• The Transactions of the Korea Information Processing Society
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• 제6권1호
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• pp.175-181
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• 1999

There are issues regarding how some of traffic parameters should be set so that ATM and non-ATM service parameters can be compatible. For example, policing method used by frame relay based on CIR(committed information rate) will not exactly match the ATM UPC(Usage Parameter Control) method. ATM and the frame relay have different transfer modes and traffic parameters. The cells and frames are police by their own traffic control schemes. For the same information, the real traffic of the ATM side takes greater bandwidth than that of the frame relay side caused by ATM cell format and AAL5 format. IN both networks this bandwidth than that of the frame relay side caused by ATM cell format and AAL5 format. In both networks this bandwidth ratio should be considered on traffic parameter mapping to maintain their QoS and to perform efficient network resource management. In this paper we describe traffic parameter mapping schemes between frame relay and ATM in ATM network and how to expect the bandwidth ratio to maintain FR QoS in ATM network. We assumed frame length distribution to Erlang or Exponential probability density function.