• 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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• 1988.07a
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• pp.487-491
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• 1988

This paper describes the universal-type signaling service equipment which provides a signaling service function (R2 MFC, DTMF, Continuity check tone, and Audible tone sending and/or receiving) for call processing control in TDX-10 switching system. Based upon the structure of the TDX-10 switching system, the philosophy of design and technology on the universal-type signaling service equipment has been investigated in order to realize a reduction in size and cost, as well as assuring high reliability and flexible operation. Finally, the control method, fuctional operation and principal feature of the designed universal-type signaling service equipment have been described.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1322-1331
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• 2000

In this paper, we compare the performance of noncoherent DS-CDMA system where orthogonal code is used for identifying the user to reduce multiple access interference or for M-ary orthogonal signaling to improve the performance of demodulation. The effects of M-ary orthogonal signaling on the noncoherent demodulation is investigated and compared with one of coherent demodulation. The analysis results show that M-ary orthogonal signaling gives better performance than quasi-synchronous orthogonal scheme for a moderate number of users when the processing gain is 128 over AWGN channel. In addition, when the number of user is 41, M=64 orthogonal signaling has a similar performance to the quasi-synchronous orthogonal scheme at the BER of 10-2 when the time misalignment between channels is within 1/2 chip and M=256 orthogonal signaling always outperforms the quasi-synchronous orthogonal scheme. Start after striking space key 2 times.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.183-188
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• 2021

In vitro maturation (IVM) of oocytes is the procedure where the immature oocytes are cultivated in a laboratory until they are mature. Since IVM oocytes generally have low developmental competence as compared to those matured in vivo, development of an optimal IVM culture system by fine-tuning culture conditions is crucial to maintain high quality. In-depth knowledge and a deep understanding of the in vivo physiology of oocyte maturation are pre-requisites to accomplish this. Within ovarian follicles, various signaling pathways that drive oocyte development and maturation regulate interaction between oocytes and surrounding somatic cells. This review discusses the sonic hedgehog (SHH) signaling pathway, which has been demonstrated to be intimately involved in folliculogenesis and oocyte maturation. Advances in elucidating the role of the SHH signaling pathway in oocyte maturation will aid attempts to improve the current inferior in vitro oocyte maturation system.

• Journal of the Korean Society of Systems Engineering
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• v.15 no.2
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• pp.108-115
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• 2019

The activities of managing and controlling the configuration of a system component over its life cycle are critical tasks in developing a high safety system as well as general system development. These configuration management activities should be defined through the management plan at the beginning of the life cycle, and should be performed continuously and systematically until the end of the project after the system or product development is completed. In this study, the configuration management process applied in the development of high safety railway signaling system was introduced and an efficient application proposals of it was proposed. In particular, configuration management through the establishment of a configuration management system based on computer tools is one of the important activities of maintaining the configuration integrity of the system or product.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.9
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• pp.1589-1595
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• 2007

This paper suggests the advanced reliability assessment tool for railway signaling Hot-Standby sparing system. Existing reliability assessment for Hot-Standby sparing system controller is done by using single module mean failure rate based on approximated Hot standby sparing system function. Although approximated Hot standby sparing system function can be applied to various Hot standby sparing system, however, it is not able to reflect the exact system structure. In this paper, we suggest the advanced reliability function by identifying changeover-related failure factors and common failure mode which is not considered in existing approximated Hot standby sparing system reliability function via developing Hot standby sparing system model for railway signaling and applying FMECA to this model. Also. we compare reliability assessment results for model system to reliability assessment for existing system.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.251-254
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• 2011

This paper describes the design and implementation of the DMI display based on ERTMS specification for the Integrated Onboard Signaling System (IOSS). IOSS is consists of ATS, ATC, and ATP based on ERTMS/ETCS Level 1. We propose an improved DMI display design which has single layout concept for the IOSS. When a train is in the ATS, ATC, or ATP railway section, it is protected by the ATS, ATC, or ATP equipment, respectively. Therefore, DMI should display the different information according to the each signaling system. We design DMI display implemented as single layout for ATP, ATS and ATC information. This single layout display has a well integrated look and feel using the ERTMS specification and layout. This is for the driver to perceive the information easily and not to experience inconvenience resulting from the sense of difference when the train crossed into the different signaling section. Finally, we show the implementation result following this concept.

• Journal of the Korean Society for Railway
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• v.6 no.2
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• pp.135-141
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• 2003

According to the computerization of railway signaling systems, the interface link between these signaling equipment is also replaced by digital communication channel, expecially communication link for interface between EIS and LDTS, but there are some problems in the present state of railway signaling. First of all, different communication protocol is applied to interface between above two signaling equipment although they have same functions. The other is that the communication protocol currently used in railway field has some unreasonable points such as structure, formation of byte, error correction scheme and etc. To solve these problems, the standard communication protocol for railway signaling is designed. The structure of designed communication protocol and the results of performance analyses are represented in this paper. It will be expected the increase of safety, reliability and efficiency of maintenance of signaling system by using of the designed communication protocol for railway signaling.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.513-519
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• 2006

As a very important part in development of the protocol, verifications for developed protocol specification are complementary techniques that are used to increase the level of confidence in the system functions by their specifications. Using the informal method for specifying the protocol, some ambiguity may be contained therein. This indwelling ambiguity in control systems can cause the occurrence of accidents, especially in the case of safety-critical systems. To clear the vagueness contained in the designed protocol, we use the LTS (Labeled Transition System) model to design the protocol for railway signaling. And then, we verify the safety and the liveness properties formally through the model checking method. The modal ${\mu}$-calculus, which is an expressive method of temporal logic, has been applied to the model checking method. We verify the safety and liveness properties of Korean standard protocol for railway signaling systems. To perform automatic verification of the safety and liveness properties of the designed protocol, a communication verification tool is implemented. The developed tools are implemented by C++ language under Windows XP. It is expected to increase the safety and reliability of communication protocol for signaling systems by using the developed communication verification tool.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.57-60
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• 1999

In many radio communication environments, there is a special component, called inter-symbol interference (ISI), mused by multipath time delay of signal and ISI components impose limitation of the data transmission rate. In this paper, we consider signaling pulse shapes, called partial response signaling (PRS), for minimizing the effect of ISI and show the improvement of performance by applying one of the partial-response signaling (PRS) pulses to two types of receiver system under dependent noise environments through the Monte-Carlo computer simulations.