• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.3
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• pp.29-32
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• 1983

This paper is an experimental study on the generation principles of digital frequency using ROM-table look-up method and the design of the MF digital Sender used in signalling systems between ESS. After construction of MF digital Sender, through experiment, we concluded that this system well suit for CCITT (International Telegraph and Telephone Consultative Committee) recommendation and this basic principle can be applied to the signalling method using frequency Within voice-band. Also it can be applied to R2 MFC signalling equipment which is used between electronic switching systems (ESS) signalling system.

• Molecules and Cells
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• v.39 no.1
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• pp.6-19
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• 2016

Redox signalling comprises the biology of molecular signal transduction mediated by reactive oxygen (or nitrogen) species. By specific and reversible oxidation of redoxsensitive cysteines, many biological processes sense and respond to signals from the intracellular redox environment. Redox signals are therefore important regulators of cellular homeostasis. Recently, it has become apparent that the cellular redox state oscillates in vivo and in vitro, with a period of about one day (circadian). Circadian timekeeping allows cells and organisms to adapt their biology to resonate with the 24-hour cycle of day/night. The importance of this innate biological timekeeping is illustrated by the association of clock disruption with the early onset of several diseases (e.g. type II diabetes, stroke and several forms of cancer). Circadian regulation of cellular redox balance suggests potentially two distinct roles for redox signalling in relation to the cellular clock: one where it is regulated by the clock, and one where it regulates the clock. Here, we introduce the concepts of redox signalling and cellular timekeeping, and then critically appraise the evidence for the reciprocal regulation between cellular redox state and the circadian clock. We conclude there is a substantial body of evidence supporting circadian regulation of cellular redox state, but that it would be premature to conclude that the converse is also true. We therefore propose some approaches that might yield more insight into redox control of cellular timekeeping.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.2
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• pp.139-146
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• 2001

L-type $Ca^{2+}$ channels play an important role in regulating cytosolic $Ca^{2+}$ and thereby regulating hormone secretions in neuroendocrine cells. Since hormone secretions are also regulated by various kinds of protein kinases, we investigated the role of some kinase activators and inhibitors in the regulation of the L-type $Ca^{2+}$ channel currents in rat pituitary $GH_3$ cells using the patch-clamp technique. Phorbol 12,13-dibutyrate (PDBu), a protein kinase C (PKC) activator, and vanadate, a protein tyrosine phosphatase (PTP) inhibitor, increased the $Ba^{2+}$ current through the L-type $Ca^{2+}$ channels. In contrast, bisindolylmaleimide I (BIM I), a PKC inhibitor, and genistein, a protein tyrosine kinase (PTK) inhibitor, suppressed the $Ba^{2+}$ currents. Forskolin, an adenylate cyclase activator, and isobutyl methylxanthine (IBMX), a non-specific phosphodiesterase inhibitor, reduced $Ba^{2+}$ currents. The above results show that the L-type $Ca^{2+}$ channels are activated by PKC and PTK, and inhibited by elevation of cyclic nucleotides such as cAMP. From these results, it is suggested that the regulation of hormone secretion by various kinase activity in $GH_3$ cells may be attributable, at least in part, to their effect on L-type $Ca^{2+}$ channels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.9
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• pp.880-886
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• 2014

Many railway signalling functions have increasingly depended on computer software with recent development in computing technology, leading to evolution into more flexible and intelligent railway signalling system. Meanwhile, software programs are likely to have many errors and the cost incurred by such errors has increased. Especially, if fatal software error occurs during railway operation, it may result in loss of lives. So the software verification and validation have become more important. It is needed for software functional safety tool to support these, but most commercial tools depend on direct access to the system's memory, resulting in many difficulties in application. Owing to such difficulties and complexity, they are rarely used in railway signalling system software validation. In this study, a new testing tool for software functional testing through an external interface that can be easily used in functional testing of software was developed. Such testing tool allows development and analysis of test cases for black-box testing through analysis of actually used interface protocols, leading to increased user convenience.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1205-1207
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• 2002

As going through technical transition of signal control logic to mechanic, electric, electronic etc., railway signalling system utilizing computer control technology has recently been developed and used since railroad service had been firstly started in 1825 by beginning that horseman kept red color sign and notified something wrong existence and nonexistence of front route to train driver in the Britain. In this paper, the domestic technical change process of signalling technology to be a basic of train control technology is discussed and then reviewed about technical trend of advanced nation's development.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.208-213
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• 2016

In order to detect the exact position of high-speed train, it is necessary to obtain location information from the transponder tag installed along the track. When the transponder tag receives the energizing signal from the train, it sends a telegram to the reader, which includes location information. In high-speed railway environment, this telegram can be corrupted by electromagnetic interference caused by onboard electric train power equipments or wayside devices. In order to assess the performance of transponder system under this harsh environment, we carried out field test using HEMU-430X. Field test results are briefly introduced and discussed for the evaluation of the transponder system under development.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.6
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• pp.621-632
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• 1989

According to the conventional network evolving towards ISDN, various connection types may be existed in the networks and subscriber-network interfaces. For this reason it is necessary to study the signalling conversion algorithms and the implementation models. In this paper, after surveying the signalling conversion method between the ISDN subscriber and the conventional network, the signaling conversion algorithms are proposed. Based on this algorithms the matching system is designed and developed. Also the validity of this system and the utility of designed software and hardware functions are verified through experiments.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.5
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• pp.369-381
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• 1991

In this paper, design algorithms for SMP(Single Mated Pair) and MMP (Multipli Mated Pair) structure of CCS (Common Channel Signaling) network are proposed through the study of the structure of CCS network. High reliability and fast messagy transfer time are the most important requirements for the CCS network. Based on it, three parameters such as monotraffic, reliability (maximum isolated SP(Signalling Point) number when any two STP(Signalling Transfer Points) fail and total network cost are defined. And the proposed algorithms different from preexisted algorithm that minimizes total network cost, maximize monotraffic with two constraints, reliability and total network cost. Comparing the experimental results of the proposed algorithms with those of the preexisted algorithm that minimizes total network cost, shows that the proposed algorithms produce a more reliable topology that has more monotraffic and a little higher total network cost. Additionaly, with the results of the proposed algorithms, SMP and MMP structures are compared.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.427-435
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• 1998

In this paper will be presented an algorithm for designing of a railway interlocking table which is a document describing the functional specification of the interlocking device. The ability to produce an interlocking table has been handed down in the signalling engineers society. And the signalling engineer makes the most of his expertise to produce an interlocking table. But, the expertise has not yet been organized into technical system, the core of the expertise is a hard nut to crack. Therefore, we analyze into signal engineering expertise, and propose a generalization of interlocking notion. Also, an algorithm is drawn up based on a train route setting principle to solve practical and general problems by computer And the performance of the algorithm is evaluated for test program based on AutoCAD technology. The evaluation result shows that it can be utilized as the effective algorithm for computer control of the signalling system as interlocking device, that it improved in safety

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1387-1389
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• 2000

Railway signalling system is required to be high safety against collision, derailment and collision at level crossing and to be high availability. The signalling system is usually divided into automatic train control, interlocking and centralized traffic control systems and each system must be high fail safe and availability. This study focused on reliability calculation of vital systems in train control system.