• International Journal of Railway
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• 제9권2호
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• pp.36-40
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• 2016

TETRA communication system is very versatile system which can transmit voice + data and packet data optimized. Direct mode operation permits to connect between mobiles when mobile stain is out of coverage of networks. It can be more secure communication channel for railway signaling systems. Railway signaling systems use many of wayside signal equipment, which require many maintenance efforts and budget. Many railway authorities want to reduce and replace the wayside equipment. Radio based signaling systems are one of candidate for replacing the conventional signaling systems. The radio based signaling systems can replace track circuit and wayside signal. The radio systems permit to connect between control centers and trains. The radio systems have to ensure high quality of the connectivity more or equal to the existed track circuits. We studied the application of TETRA systems for railway radio systems for bridging between train control centers and trains. We provide an operation scenario for radio based train control system to ensure the safety require to the existed trains control system and satisfied the existed operational availability. We showed the data transmission speed, maximum bit error rate, and data coding for the radio-based signal system using TETRA systems.

• 한국철도학회논문집
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• 제12권4호
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• pp.450-456
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• 2009

최근의 컴퓨터 기술의 발달에 따라 열차제어시스템들이 컴퓨터 소프드웨어에 의존성이 더옥 증가되고 있으며, 이에 따라 이러한 열차제어시스템 소프트웨어의 안전성과 선뢰성에 대한 테스팅이 더욱 증요하게 되었다. 본 논문에서는 이러한 열차제어시스템 소프트웨어를 위한 Metrics 분석 자동화 도구를 제안하였으며, 또한 구현결과를 제시하였다. S/W Metrics는 철도시스템 소프트웨어관련 국제표준에서 언급되고 있는 Metrics를 대상으로 하였으며, 철도 소프트웨어 소스코드의 Metrics를 자동으로 분석하여 그 결과를 사용자에게 다양한 형태로 제시할 수 있도록 구현하였다. 자동화 도구는 열차제어시스템 소프트웨어 평가단계에서도 활용될 수 있고 또한 소프트웨어 개발단계에서도 유용하게 활용될 수 있을 것으로 예상된다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제3B권4호
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• pp.195-201
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• 2003

In accordance with the computerization of railway signaling systems, the interface link between signaling equipment has been replaced by a digital communication channel and the importance of this communication link has become increasingly significant. However, there are some problems with the present state of railway signaling. First, different communication protocol is applied to interfaces between signaling although they have the same functions. Next, the communication protocols currently used in the railway fields contain various illogical components such as structure, byte formation, error correction scheme and so on. To solve these matters, a new data link protocol for railway signaling systems is designed. In this paper, the structure of protocol and the results of performance analyses are presented. It will be expected to increase the safety, reliability and efficiency of maintenance of signaling systems by using the designed communication protocol for railway signaling in Korea.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.205-207
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• 2008

Much signaling equipments are installed along railway tracks, and these are working in cooperation with each other, referring to other signaling equipment status. Existing railway signaling system uses signal cables to transmit this information. This system requires high cost for construction and have the problems like many faults from mistakes in cable connection, etc To solve these problems, JREast Inc. has developed a new signaling system based on network technology, utilizing Ethernet-Passive Optical Network(E-PON). In this paper, we review the system proposed by JREast Inc. and field test results performed on railway.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.319-326
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• 2001

Railway signaling safety system organizes equipments and facilities of railway, increases transport efficiency and assures safe operation of railway. In the early days of signaling system railway managers made sure of safety by using relay logic technology based on fail-safe concept. But the development result of computer and science having been introduced to railway industry, railway signaling equipments begin to be operated through micro electronic control system. Accordingly high speed and high density operation of train became possible. Software reliability and safety technology that controls important systems of railway was highlighted. In the middle of 1990s the standard or guideline of railway reliability and safety were studied and established, and are being reviewing in Europe, Japan etc. Our reliability and safety technology have depended largely on foreign countries. In this study we performed a basic study about the reliability of software that controls the railway signaling system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1420-1422
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• 2000

The railway signaling system consists of micro-computerized vital devices on board and ground, which are connected to one another by track circuits, and interlocking equipment for route control. Therefore it is important to validate the required functions of developed system and interface between developed signaling systems. To verify the conditions and functions of signaling functions, the laboratory prototype test bench, which consists of personal computers LAN, will be developed. In this paper design of signaling system test-bench for high-speed signaling is described and developed software module are presented.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 춘계학술대회 논문집
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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.

• Reproductive and Developmental Biology
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• 제36권1호
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• pp.13-19
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• 2012

In order to provide the basis for developing practical mouse embryonic stem cells (mESCs) culture method, how the endogenous level of self-renewal-stimulating factor genes was altered in the mESCs by different extracellular signaling was investigated in this study. For different extracellular signaling, mESCs were cultured in 2 dimension (D), 3D and integrin-stimulating 3D culture system in the presence or absence of leukemia inhibitory factor (LIF) and transcriptional level of $Lif$, $Bmp4$ and $Wnt3a$ was evaluated in the mESCs cultured in each system. The expression of three genes was significantly increased in 3D system relative to 2D system under LIF-containing condition, while only $Wnt3a$ expression was increased by 3D culture under LIF-free condition. Stimulation of integrin signaling in mESCs within 3D system with exogenous LIF significantly up-regulated transcriptional level of $Bmp4$, but did not induce transcriptional regulation of $Lif$ and $Wnt3a$. In the absence of LIF inside 3D system, the expression of $Lif$ and $Bmp4$ was significantly increased by integrin signaling, while it significantly decreased $Wnt3a$ expression. Finally, the signal from exogenous LIF significantly caused increased expression of $Lif$ in 2D system, decreased expression of $Bmp4$ in both 2D and 3D system, and decreased expression of $Wnt3a$ in integrin-stimulating 3D system. From these results, we identified that endogenous expression level of self-renewal-stimulating factor genes in mESCs could be effectively regulated through artificial and proper manipulation of extracellular signaling. Moreover, synthetic 3D niche stimulating endogenous secretion of self-renewal-stimulating factors will be able to help develop growth factor-free maintenance system of mESCs.

• International Journal of Railway
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• 제5권2호
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• pp.77-83
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• 2012

Railroad signaling systems are to control intervals and routes of trains. There are ATS, ATP, ATO and ATC system. Trains are operated in the section which is met on the signaling system because various signaling systems are used in Korea. Hence, trains are not operated in the section which is used in the other signaling system. To solve this problem, recently combined on-board system has been developed. The combined on-board system designed by doubling the ATS, ATP and ATC system to ensure the safety of system. The inductance of antenna is change and in return the resonance frequency of antenna is varied by the electromagnetic induction. Therefore, the information signal is not received exactly in the combined on-board system and in return accidents between trains occur. In this paper, electric model of the combined on-board system for considering the ATS and ATP antenna is presented. Moreover, the mutual inductance including the distance between the ATS and ATP antenna is calculated. As a result of the frequency response of the antennas, the mutual inductance met on operation range of resonance frequency is defined.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.163-165
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• 2008

A S/W testing for vital railway signaling system have been important because of the increase of software usage for signaling. And also the safety of vital signaling system is required by int'l std. such as IEC 61508. While much efforts have been reported to improve electronic hardware's safety, not so much systematic approaches to assessment software's safety. In this paper, we propose a automation schemen of software testing tool for railway signaling system. From that, we show the functional architecture and internal components of the tool.