• Journal of applied mathematics & informatics
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• v.12 no.1_2
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• pp.395-408
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• 2003

Common Channel Signaling(CCS) networks need special controls to avoid overload of signaling networks and degradation of call process-ing rate, since they play an important role of controlling communication transfer networks. Congestion control and flow control mechanisms are well described in ITU-T recommendation on Signaling System No.7(SS7). For the practical provisions, however, we need an analysis on the relation among service objects, system requirements and implementation of congestion control algorithms. SS7 provides several options for controlling link congestion in CCS networks. In this paper we give a general queueing model of congestion control algorithm which covers both the international and national options. From the queuing model, we obtain the performance parameters such as throughput, message loss rate and mean delay for the international option. To show the performance of the algorithm, some numerical results are also given.

• ETRI Journal
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• v.24 no.2
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• pp.69-81
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• 2002

This paper reviews the existing research activities on signaling and control procedures for IP over optical networks. We focus on the IP-centric signaling and control architecture based on the generalized multi-protocol label switching (GMPLS) protocol and analyze various scenarios and technical issues for deploying the IP over an optical network. We analyze the signaling and operations and administration and maintenance requirements for integrating an IP network and an optical network in order to cope with the high bandwidth and poor resource granularity of the optical network, including the optical cross-connect system. On the basis of network architecture and a reference configuration model, we investigate the GMPLS-based control architecture and interconnection model appropriate for controlling IP bandwidth and optical lambda resources. The signaling and control procedure based on GMPLS on optical user-network interface and network-network interface are comparatively investigated to provide the optical lightpath. We also study protection and restoration procedures to protect link failure when it applies to generalized MPLS signaling.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1377-1386
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• 2000

As all delays resulting from the signaling network directly affect the response time of network management activity, all control informations have to be transported most efficiently. It is very important to know the performance of the signaling system not only because of smooth network operation but also because of efficient engineering of signaling networks. In this paper, we analyzed mean queueing delay of signaling link for ISUP signaling messages in common channel signaling system by using M[X]/G/1 and M[X]/D/1 batch arrival queueing system. This is because we modeled arrival process of the signaling messages as batch arrival process considering that many kinds of signaling messages are generated at short intervals when a call requests a connection. Analysis was carried out considering different call processing scenario based on ITU-T specification. We also described the numerical results from the different types of queueing models.

• Journal of the Korean Society for Railway
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• v.15 no.1
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• pp.42-47
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• 2012

There are ATC (Automatic Train Control), ATP (Automatic Train Protection), ATS (Automatic Train Stop) and ATO (Automatic Train Operation) etc. in train control systems. As various train control systems are installed according to sections, on-board signaling systems are installed to apply to the section. Hence, operation flexibility of trains is decreased. In other words, when trains are operated in the section where other train control systems are used, the on-board signaling systems are changed. Recently, a study on the combined on-board signaling system has been researched to solve this problem. The combined on-board signaling system consists of ATC, ATP and ATS device. Because the train control systems are vital, it needs to design the combined on-board signaling system by using k out of n system. In this paper, when k out of n system is applied in the combined on-board signaling system, the reliability and loss cost are analyzed by using failure rate in each device. Hence, the ideal number of systems is presented according to the number of outputs.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1145-1146
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• 2008

Failures of equipments are linked directly to extensive damages of human lives or financial losses from the increasing uses of railway signaling equipments utilizing computers. Then safety organizations have to establish for guaranteeing safety during the system life-cycle. In this paper, we examine the relationship between railway signaling standards and other safety standards for safety meaning establishment.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.358-362
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• 2004

Verification and testing are complementary techniques that are used to increase the level of confidence in the correct functioning of communication systems as prescribed by their specifications. This paper presents an experience of model checking for a formal railway signaling protocol specified in LTS (Labeled Transition System). This formal approach checks deadlock, livelock and reachability for the state and action to verify whether properties expressed in modal logic are true on specifications. We also propose a formal method for semi-automated test case generation for a railway signaling protocol described in I/O FSM (Input/Output Finite State Machine). This enables the generation of more complete and consistent test sequence for conformance testing. The above functions are implemented by C++ language and included within RSPVTE (Railway Signaling Protocol Verification and Testing Environment).

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1220-1222
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• 2002

The railway signaling system consists of several vital computerized equipments. Now the project for development of signaling system for the next-generation high-speed train is progressed according to the consortium. The developing signaling system by this project, kTCS(Korean Train Control System), is composed of kTCS-CTC, kTCS-IXL, kTCS-ATC and etc. The KTCS signaling has to be operated as a integrated system by interface between each signaling. To achieve these, communication protocols between each signaling have to be designed and message codes are defined. In this paper the configuration of integrated kTCS system and designed communication protocol is presented.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.7
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• pp.1019-1025
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• 2015

The performance requirements on the safety-based functionality of railway signal systems have been reinforced and the effort for enhancement of the existing system or development of the new system is being accordingly made. In particular, various technical researches on replacement or improvement of the existing ATS(Automatic Train Stop) signaling system are now in progress for better operational efficiency. In this study, the complementary points for improvement or replacement of the currently used system(i.e., ATS) will be derived in terms of operating efficiency in an integrated operating environment with the newly introduced system(e.g., ATC: Automatic Train Control). This study can contribute to derive the need for improvement of the signaling system by checking the interface problems and comparing between different systems through the analysis of real operation cases in the field. Eventually, this analysis can be applied to prevent and estimate the collision accidents can be caused by the failure of the signaling system in advance. In addition, the results can be used to provide a future direction to secure the reliability in the parallel operation by integration based on different railway signaling systems.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.299-306
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• 1999

The ${\mu}$-processor based-controlled system is widely used in railway signaling system. The railway signaling systems are highly required safety and reliability. It is necessary to have a fault-tolerant and fail safe concept in ${\mu}$-processor based railway signaling system. In this paper, several architectures and circuits of fault-tolerant computer system is reviewed. The basic concept of the fault-tolerant computer system will be adapted total self checking, strong fail safe, fault display circuit, logic testing circuit and system switching concepts.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.355-361
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• 2002

There are many economic and operational reasons to integrate fire alarm signaling system with other building automation system. Integration of this requires open network with for the standard communication protocol and careful design practices. The important point for this is also the development of intelligent control modules for replacing the conventional zone adapter in fire system. Therefore, this paper proposes an new conceptual design of the open distributed fire alarm signaling system for the integration of BAS, a new intelligent control modules with LonTalk protocol and a new control modules for power line communication. Newly proposed additions to LonWorks network make it very well suited for integrating fire systems with other building automation sub-systems and another BAS with low cost. Additionally, it is very important that best design practices, test procedures and building codes need to be modernized to accommodate integrated building systems.