• Journal of the Korean Society for Railway
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• v.7 no.2
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• pp.114-119
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• 2004

According to the computerization of railway signalling systems. the communication protocol for interface between these systems are required. Therefore the new communication protocol for railway signaling system is required. Generally, there are two verification method for new designed protocol in the industrial and academic fields. One is the laboratory testing method which is very popular and general technique. In our research the comparison between existing and new designed protocol for signaling is described and the verification test results are also represented. From these laboratory test, we are verified the conformance of new designed protocol. Another method is verified by formal method. The format verification method is widely used at safety-critical system design but this approach is nor popular at verification communication protocol. However it is very important to verify the safety of new designed protocol for railway signaling system because signaling systems are very safety-critical systems. So, the methodology for formal verification of designed protocol is also reviews in this paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.8
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• pp.1456-1463
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• 2010

The safety critical systems in nuclear power plants should be designed to have a high level of fault tolerant capability because those systems are used for protection or mitigation of the postulated accidents of nuclear reactor. Due to increasing of the system complexity of the digital based system in nuclear fields, the reliability of the digital based systems without an auto-test or a self-diagnostic feature is generally lower than those of analog system. To overcome this problem, additional redundant architectures in each redundant channel and self-diagnostic features are commonly integrated into the digital safety systems. The self diagnostic function is a key factor for increasing fault tolerant capabilities in the digital based safety system. This paper presents an availability and safety evaluation model to analyze the effect to the system's fault tolerant capabilities depending on self-diagnostic features when the loss or erroneous behaviors of self-diagnostic function are expected to occur. The analysis result of the proposed model on the several modules of a safety platform shows that the improvement effect on unavailability of each module has generally become smaller than the result of usage of conventional models and the unavailability itself has changed significantly depending on the characteristics of failures or errors of self-diagnostic function.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1201-1202
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• 2007

Safety critical systems are those in which a failure can have serious and irreversible consequences. Nowadays digital technology has been rapidly applied to critical system such as railways, airplanes, nuclear power plants, vehicles. The main difference between analog system and digital system is that the software is the key component of the digital system. The digital system performs more varying and highly complex functions efficiently compared to the existing analog system because software can be flexibly designed and implemented. The flexible design make it difficult to predict the software failures. This paper reviews safety standard and criteria for safety critical system such as railway system and introduces the framework for the software lifecycle. The licensing procedure for the railway software is also reviewed.

• IEMEK Journal of Embedded Systems and Applications
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• v.16 no.6
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• pp.267-276
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• 2021

The automotive industry and academic research have been continuously conducting research on standardization such as AUTOSAR (AUTomotive Open System ARchitecture) and ISO26262 to solve problems such as safety and efficiency caused by the complexity of electric/electronic architecture of automotive. AUTOSAR is an automotive standard software platform that has a layered structure independent of MCU (Micro Controller Unit) hardware, and improves product reliability through software modularity and reusability. And, ISO26262, an international standard for automotive functional safety and suggests a method to minimize errors in automotive ECU (Electronic Control Unit)s by defining the development process and results for the entire life cycle of automotive electrical/electronic systems. These design methods are variously applied in representative automotive safety-critical systems. However, since the functional and safety requirements are different according to the characteristics of the safety-critical system, it is essential to research the AUTOSAR functional safety design method specialized for each application domain. In this paper, a software functional safety mechanism design method using AUTOSAR is proposed, and a new failure management framework is proposed to ensure the high reliability of the product. The AUTOSAR functional safety mechanism consists of memory partitioning protection, timing monitoring protection, and end-to-end protection. The fault management framework is composed of several safety SWCs to maintain the minimum function and performance even if a fault occurs during the operation of a safety-critical system. Finally, the proposed method is applied to the Shift-by-Wire system design to prove the validity of the proposed method.

• Journal of Korea Multimedia Society
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• v.14 no.3
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• pp.440-448
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• 2011

The needs for the OpenGL-family of the rendering library standards are highly increasing, especially for the graphical human-machine Interface on the various systems including smart phones and personal information devices. Additionally, in the case of safety-critical market for avionics, military, medical and automotive applications, OpenGL SC, the safety critical profile of the OpenGL library plays the major role for the graphical interfaces. In this paper, we represent our OpenGL SC emulation library on the OpenGL 1.x rendering pipeline which is widely available on the existing embedded systems, to provide the features of OpenGL SC standard cost-effectively. Our method can provide the OpenGL SC features at the low development cost on the embedded systems, and its implementation is also one of the fundamental elements for the emulation of embedded systems in the PC environment. Our final result now works on both of Linux-based and VxWORKS systems, showing correct execution results at the reasonable speed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.363-368
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• 2016

In safety-critical systems (SCS), failure may result in accidents with serious damage to human beings and property. As systems become more complex and automated, the goal of acquiring safety has attracted increasing attention lately in the defense industry, as well as the rail, automotive, and aerospace industries, among others. As such, the Department of Defense and international organizations have established appropriate standards and guidelines for systems safety and design. To this end, there has been research on the processes, methods, and associated tools for safety design. However, those results do not seem to sufficiently utilize system architectural information. The purpose of this paper is to provide a more systematic approach to SCS design. To better identify potential hazards, design information at each level of system hierarchy is exploited. Based on the results, an integrated process model was developed by combining the processes of system design and safety analysis. As a case study, the resultant integrated process model was applied to the safety design of an automobile system, which shows useful results for safety evaluation.

• Nuclear Engineering and Technology
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• v.41 no.6
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• pp.849-858
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• 2009

Risk caused by safety-critical instrumentation and control (I&C) systems considerably affects overall plant risk. As digitalization of safety-critical systems in nuclear power plants progresses, a risk model of a digitalized safety system is required and must be included in a plant safety model in order to assess this risk effect on the plant. Unique features of a digital system cause some challenges in risk modeling. This article aims at providing an overview of the issues related to the development of a static fault-tree-based risk model. We categorize the complicated issues of digital system probabilistic risk assessment (PRA) into four groups based on their characteristics: hardware module issues, software issues, system issues, and safety function issues. Quantification of the effect of these issues dominates the quality of a developed risk model. Recent research activities for addressing various issues, such as the modeling framework of a software-based system, the software failure probability and the fault coverage of a self monitoring mechanism, are discussed. Although these issues are interrelated and affect each other, the categorized and systematic approach suggested here will provide a proper insight for analyzing risk from a digital system.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.1097-1098
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• 2005

• Journal of the Korean Society for Railway
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• v.6 no.1
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• pp.1-9
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• 2003

This article proposes an integrated systems engineering and safety analysis model for safety-critical systems development. A methodology in system design for safety is considered during the early phase of the development life cycle of systems engineering process. The evolution of the design automation technology has enabled engineers to perform the model-based systems engineering. A Computer-Aided Systems Engineering(CASE) tool, CORE, is utilized to integrate the systems engineering model with a system safety analysis model. The results of the functional analysis phase can drive the analysis of the system safety. An example of Communications-Based Train Control(CBTC) system for an Automated Guided Transit(AGT) system demonstrated an application of the integrated model.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.10
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• pp.933-939
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• 2007

Safety critical systems such as x-by-wire systems require in-vehicle network systems that can interconnect various sensors, actuators, and controllers. These networks need to have high data rate, deterministic operation, and fault tolerance. Recently, FlexRay protocol that is a time-triggered protocol has been introduced, and many automotive companies have been focusing on this protocol. This paper presents a design method of FlexRay network system and implementation of FlexRay-based motor control system.