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

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.

Author(s):  
Arash Aziminejad ◽  
Andrew W. Lee

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.


2012 ◽  
Vol 2 (2) ◽  
pp. 68-90 ◽  
Author(s):  
PhaniKumar Singamsetty ◽  
SeethaRamaiah Panchumarthy

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.


Author(s):  
Sasi Bhanu Jammalamadaka ◽  
Vinaya Babu A ◽  
Trimurthy P

<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>


2013 ◽  
Vol 765-767 ◽  
pp. 1227-1230
Author(s):  
Juan Zhang ◽  
Guo Qi Li ◽  
Xiao Liu

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.


Author(s):  
Jonathan Ostroff ◽  
Susan Gerhart ◽  
Dan Craigen ◽  
Ted Ralston ◽  
Nancy G. Leveson ◽  
...  

Author(s):  
Abdulaziz Ahmed Thawaba ◽  
Azizul Azhar Ramli ◽  
Mohd. Farhan Md. Fudzee ◽  
Junzo Wadata ◽  
◽  
...  

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.


2007 ◽  
Vol 15 (1) ◽  
pp. 77-94 ◽  
Author(s):  
H.A. Thompson ◽  
D.N. Ramos-Hernandez ◽  
J. Fu ◽  
L. Jiang ◽  
I. Choi ◽  
...  

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