Providing Network Resilience for Safety Critical Systems

2014 ◽  
Author(s):  
Arash Aziminejad ◽  
Andrew W. Lee
Keyword(s):  
Information Age ◽  
Simulation Models ◽  
Cost Effective ◽  
Design Parameters ◽  
Critical Systems ◽  
Critical System ◽  
Safety Critical ◽  
Safety Critical System ◽  
Safety Critical Systems ◽  
Selection Of

Ethernet was commercially introduced in 1980 and standardized in 1985 as IEEE 802.3. Due to the instability and unreliability of the initial introduction, safety critical systems have been slow to adapt Ethernet technologies. It is only until the Information Age brought on by the globalization of Internet in the 1990s that network gears become more cost effective, reliable, and technically suitable. With many Ethernet technologies to pick from, selection of a suitable network topology can be challenging. This paper offers insight on the problem of the optimum choice of an Ethernet technology for the purpose of safety critical system. Example of a typical CBTC system will be given along with the key design parameters and several Ethernet technologies analyzed. Simulation models are built on the basis of the two most common Ethernet technologies to provide means of comparison, and numerical results are presented in the paper.

Diversity and Multi-Version Systems

2014 ◽  
pp. 178-232
Author(s):  
Alexander Siora ◽  
Vladimir Sklyar ◽  
Vyacheslav Kharchenko ◽  
Eugene Brezhnev
Keyword(s):  
Printed Circuit Boards ◽  
Linguistic Diversity ◽  
Cost Effective ◽  
Ordinal Scale ◽  
Critical Systems ◽  
Safety Critical ◽  
Common Cause Failures ◽  
Safety Critical Systems ◽  
Diversity Strategy ◽  
Selection Of

To protect safety-critical systems from common-cause failures that can lead to potentially dangerous outcomes, special methods are applied, including multi-version technologies operating at different levels of diversity. A model representing different diversity types during the development of safety-critical systems is suggested. The model addresses diversity types that are the most expedient in providing required safety. The diversity of complex electronic components (FPGA, etc.), printed circuit boards, manufacturers, specification languages, design, and program languages, etc. are considered. The challenges addressed are related to factors of scale and dependencies among diversity types, since not all combinations of used diversity are feasible. Taking these dependencies into consideration, the model simplifies the choice of diversity options. This chapter presents a cost effective approach to selection of the most diverse NPP Reactor Trip System (RTS) under uncertainty. The selection of a pair of primary and secondary RTS is named a diversity strategy. All possible strategies are evaluated on an ordinal scale with linguistic values provided by experts. These values express the expert’s degree of confidence that evaluated variants of secondary RTS are different from primary. All diversity strategies are evaluated on a set of linguistic diversity criteria, which are included into a corresponding diversity attribute. The generic fuzzy diversity score is an aggregation of the linguistic values provided by the experts to obtain a collective assessment of the secondary RTS’s similarity (difference) with a primary one. This rational diversity strategy is found during the exploitation stage, taking into consideration the fuzzy diversity score and cost.

Optimized Selection of Reliable and Cost-Effective Safety-Critical System Architectures

2020 ◽  
Vol 39 (10) ◽  
pp. 2109-2123
Author(s):  
Pierluigi Nuzzo ◽  
Nikunj Bajaj ◽  
Michael Masin ◽  
Dmitrii Kirov ◽  
Roberto Passerone ◽  
...  
Keyword(s):  
Cost Effective ◽  
Critical System ◽  
System Architectures ◽  
Safety Critical ◽  
Safety Critical System ◽  
Selection Of

Automatic Fuzzy Parameter Selection in Dynamic Fuzzy Voter for Safety Critical Systems

2012 ◽  
Vol 2 (2) ◽  
pp. 68-90 ◽  
Author(s):  
PhaniKumar Singamsetty ◽  
SeethaRamaiah Panchumarthy
Keyword(s):  
Parameter Selection ◽  
Safety Performance ◽  
Critical Systems ◽  
Statistical Parameters ◽  
Critical System ◽  
Safety Critical ◽  
Safety Critical System ◽  
Safety Critical Systems ◽  
Fuzzy Parameter ◽  
Free Dynamic

The main objective of this research paper is designing automatic fuzzy parameter selection based dynamic fuzzy voter for safety critical systems with limited system knowledge. Existing fuzzy voters for controlling safety critical systems and sensor fusion are surveyed and safety performance is empirically evaluated. The major limitation identified in the existing fuzzy voters is the static fuzzy parameter selection. Optimally selected static fuzzy parameters work only for a particular set of data with the known data ranges. In this paper, a dynamic or automatic fuzzy parameter selection method for fuzzy voters is proposed based on the statistical parameters of the local set of data in each voting cycle. Safety performance is empirically evaluated by running the static and dynamic fuzzy voters on a simulated triple modular redundant (TMR) system for 10000 voting cycles. Experimental results show that proposed Dynamic fuzzy voter is giving almost 100% safety if two of the three modules of the TMR System are error free. Dynamic voter is designed in such a way that it can be plugged in and used in any safety critical system without having any knowledge regarding the data produced and their ranges.

Task Scheduler Based Design of Software Architecture for Distributed Timed Automata in Safety Critical Systems

2011 ◽  
Vol 403-408 ◽  
pp. 3430-3437
Author(s):  
Yogendra Namjoshi
Keyword(s):  
Software Architecture ◽  
Real Time ◽  
Timed Automata ◽  
Critical Systems ◽  
Critical System ◽  
Signaling Systems ◽  
Safety Critical ◽  
Safety Critical System ◽  
System A ◽  
Safety Critical Systems

The paper revisits the approach of distributed timed automata in order to improve and optimize the methodology used in order to increase the availability of a safety critical system and implements using embedded real time task scheduler. A double wheel counter or digital axle counter system, a typical safety critical system that is used in solid state based railway signaling systems, is considered for achieving higher availability under certain failures. The improvement in the software architecture is influenced by the theory of task scheduler of real time operating system.

scholarly journals Implementing Syntax Evolution of Embedded Systems

2015 ◽  
Vol 5 (6) ◽  
pp. 1525
Author(s):  
Sasi Bhanu Jammalamadaka ◽  
Vinaya Babu A ◽  
Trimurthy P
Keyword(s):  
Embedded Systems ◽  
Embedded System ◽  
Critical Systems ◽  
Internet Communication ◽  
Critical System ◽  
Safety Critical ◽  
Safety Critical System ◽  
Remote Locations ◽  
Safety Critical Systems ◽  
The Embedded System

<p>Safety critical systems such as nuclear recator systems cannot be shutdown as restrating is a huge process and incurs heavy cost.  The embedded systems which are used for monitoring and controlling the safety critival systems cannot be shut down as well. ES systems which drives safety critical systems must be communicated from remote locations generally through a HOST connected on to Internet. Communication between the HOST and ES system is done using commnd lanaguage which has to be evolved from time to time.  The chnage to the commnd lanauage must be undertaken while the embedded system is up and running, the evolution thus must be dynamic. Many architetcuers have been propsoed in the lieteratuer for evolving  synatx of command lanaguage.The implemntaion of effcient architetcuer as such has not been found in the literatuer without which existing architetcuer as such has no menaing.</p><p>The paper presntes a set of methods using which the syntax evolution of embedded systems as such can be achived. The synatx evolution methods have been applied to a safety critical system that monitors and controls tempartuers within a Nuclear recator system.</p>

Diversity and Multi-Version Systems

2017 ◽  
pp. 535-592
Author(s):  
Alexander Siora ◽  
Vladimir Sklyar ◽  
Vyacheslav Kharchenko ◽  
Eugene Brezhnev
Keyword(s):  
Printed Circuit Boards ◽  
Linguistic Diversity ◽  
Cost Effective ◽  
Ordinal Scale ◽  
Critical Systems ◽  
Safety Critical ◽  
Common Cause Failures ◽  
Safety Critical Systems ◽  
Diversity Strategy ◽  
Selection Of

To protect safety-critical systems from common-cause failures that can lead to potentially dangerous outcomes, special methods are applied, including multi-version technologies operating at different levels of diversity. A model representing different diversity types during the development of safety-critical systems is suggested. The model addresses diversity types that are the most expedient in providing required safety. The diversity of complex electronic components (FPGA, etc.), printed circuit boards, manufacturers, specification languages, design, and program languages, etc. are considered. The challenges addressed are related to factors of scale and dependencies among diversity types, since not all combinations of used diversity are feasible. Taking these dependencies into consideration, the model simplifies the choice of diversity options. This chapter presents a cost effective approach to selection of the most diverse NPP Reactor Trip System (RTS) under uncertainty. The selection of a pair of primary and secondary RTS is named a diversity strategy. All possible strategies are evaluated on an ordinal scale with linguistic values provided by experts. These values express the expert's degree of confidence that evaluated variants of secondary RTS are different from primary. All diversity strategies are evaluated on a set of linguistic diversity criteria, which are included into a corresponding diversity attribute. The generic fuzzy diversity score is an aggregation of the linguistic values provided by the experts to obtain a collective assessment of the secondary RTS's similarity (difference) with a primary one. This rational diversity strategy is found during the exploitation stage, taking into consideration the fuzzy diversity score and cost.

Compare of Formal Analysis and Testing for Verification of Safety-Critical Systems: A Case Study

2013 ◽  
Vol 765-767 ◽  
pp. 1227-1230
Author(s):  
Juan Zhang ◽  
Guo Qi Li ◽  
Xiao Liu
Keyword(s):  
Formal Analysis ◽  
Critical Systems ◽  
Critical System ◽  
Safety Critical ◽  
Safety Critical System ◽  
Safety Critical Systems

Safety-critical system attracts more attention in recent years. During the development of safety-critical systems, verification plays the most important role and includes many high cost activities. Testing and formal analysis are two mainstream ways for verification. This paper describes new tools and procedures for testing and formal analysis for verification of safety-critical systems. Compare them in detail in a case study. Conclusion and future works are given finally.

Characteristics for Performance Optimization of Safety-Critical System Development (SCSD)

2020 ◽  
Vol 24 (2) ◽  
pp. 232-242
Author(s):  
Abdulaziz Ahmed Thawaba ◽  
Azizul Azhar Ramli ◽  
Mohd. Farhan Md. Fudzee ◽  
Junzo Wadata ◽  
◽  
...  
Keyword(s):  
Flight Control ◽  
Performance Optimization ◽  
System Development ◽  
Critical Systems ◽  
Critical System ◽  
Safety Critical ◽  
Railway Systems ◽  
Safety Critical System ◽  
Nuclear Systems ◽  
Causes Of Failure

Safety-critical systems (SCS) are the most significant systems that affect our daily life in many areas such as flight control systems, railway systems, medical devices, nuclear systems, and military weapons. SCS failures could result in losing life or serious injuries. Improving the practices during development phases of SCS can reduce failures up to 40%, thus resulting developers to follows specific development practices and techniques. Developers should improve safety-critical system development (SCSD) by taking into account all factors and understanding the causes of failure. Previous studies have highlighted the causes of failure during the development of SCS, but for specific areas such as designs, requirements, or the human factor, while developers need to know the causes of failure in all areas and the relationship between them clearly and comprehensively. This research aims to analyze SCSD characteristics and discuss performance improvement as well as causes of failure. This paper proposed a guideline that helps developers reduce the causes of failure during SCS development. This guide has four characteristics, each with a role in improving SCSD and reducing causes of failure.

Knowledge engineering in the communication of Information for safety critical systems

1997 ◽  
Vol 12 (3) ◽  
pp. 249-270 ◽  
Author(s):  
CORIN A. GURR
Keyword(s):  
Knowledge Engineering ◽  
Distributed Teams ◽  
Primary Role ◽  
Knowledge Based Systems ◽  
Critical Systems ◽  
Human Communication ◽  
Critical System ◽  
Safety Critical ◽  
Knowledge Based ◽  
Safety Critical Systems

The design and assessment of safety critical systems often involves broad and distributed teams of designers, suppliers and analysts who represent diverse areas of expertise and motivations. Accurate and effective communication between these groups is therefore an issue of primary importance. The formalisation of specifications and arguments of safety can be of significant benefit in ensuring the consistency of evidence in such cases, when it must be presented across many domains. However, a formal description of a safety critical system may be unconvincing unless it is presented in a form which is (or forms which are) accessible to the broad range of users and assessors of safety cases. This raises issues of human communication which include the tailoring of information to particular communicative tasks; the efficacy of differing media for communication and the cognitive impact that such differing media have. This paper draws together work in fields of knowledge engineering, knowledge based systems and human communication in an effort to address, from a sound theoretical basis, these and other communication issues raised by the use of formal descriptions in safety critical systems. Further, this paper argues that a primary role for knowledge based systems techniques in safety critical systems is in supporting the communication of information.

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