Safety-Critical Systems Dependability   Engineering and International Standards              Saleh Al-Da’ajeh          Sal...
1Introduction Overview Safety -Critical Systems Safety -Critical Systems Applications, Characteristics, and other Terminol...
Software Systems Development                                 Development PhasesIntroductionOverviewSafety -Critical System...
Problems Developing Software Systems                                 Software Engineers Role in Solving ProblemsIntroducti...
Safety-Critical Systems                                 Definition and ApplicationsIntroductionOverviewSafety -Critical Sy...
Safety-Critical Systems Applications                                 Common Characteristics, and Other TerminologiesIntrod...
Safety-Critical Systems Dependability                                 Fundamental Concepts of DependabilityIntroductionOve...
Dependability Taxonomy                                 Dependability ExposedIntroductionOverviewSafety -Critical SystemsSa...
The Threats: Faults, Error, Failure                                    Faults are further investigated enclosing various a...
Faults AnalysisIntroductionOverviewSafety -Critical SystemsSafety -Critical SystemsApplications, Characteristics,and other...
Failure AnalysisIntroductionOverviewSafety -Critical SystemsSafety -Critical SystemsApplications, Characteristics,and othe...
Attributes According to the Larpie and /ISO 9126IntroductionOverview                           Dependability consists of a...
Achieving Dependability Quality Attributes                                 Verification, Validation, and EngineeringIntrod...
Means to Achieve Dependability to Safety                                 -Critical SystemsIntroductionOverviewSafety -Crit...
Is the solution to give up on our use of software                                 for such purposes altogether?!Introducti...
Thank you all for attending this seminar.    Questions are most welcomed !
Upcoming SlideShare
Loading in...5
×

Presentation

81

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
81
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
1
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Presentation

  1. 1. Safety-Critical Systems Dependability Engineering and International Standards Saleh Al-Da’ajeh Saleh.aldaajeh@adpoly.ac.ae http://www.adpoly.ac.ae December 23, 2012 jjlogo
  2. 2. 1Introduction Overview Safety -Critical Systems Safety -Critical Systems Applications, Characteristics, and other Terminologies2Dependability Taxonomy Threats on Safety -Critical Systems Dependability Dependability Attributes3Means to Achieve Dependability Achieving Dependability Quality Attributes4Summary
  3. 3. Software Systems Development Development PhasesIntroductionOverviewSafety -Critical SystemsSafety -Critical SystemsApplications, Characteristics,and other TerminologiesDependabilityTaxonomyThreats on Safety -CriticalSystems DependabilityDependability AttributesMeans to AchieveDependabilityAchieving DependabilityQuality AttributesSummary Figure: Waterfall Model - Typical Software Development Phases Saleh Al-Da’ajeh Safety-Critical Systems Dependability December 23, 2012 3/16
  4. 4. Problems Developing Software Systems Software Engineers Role in Solving ProblemsIntroductionOverviewSafety -Critical SystemsSafety -Critical SystemsApplications, Characteristics,and other TerminologiesDependabilityTaxonomyThreats on Safety -CriticalSystems DependabilityDependability AttributesMeans to AchieveDependabilityAchieving DependabilityQuality AttributesSummary Saleh Al-Da’ajeh Safety-Critical Systems Dependability December 23, 2012 4/16
  5. 5. Safety-Critical Systems Definition and ApplicationsIntroductionOverviewSafety -Critical Systems According to John C. Knight, Safety Critical Systems are thoseSafety -Critical SystemsApplications, Characteristics, systems whose failure could result in a catastrophic consequencesand other Terminologies such as loss in life.DependabilityTaxonomy Examples of Safety-Critical Systems Applications andThreats on Safety -CriticalSystems Dependability Catastrophic Consequences:Dependability Attributes Loss of the Mars Polar Lander 1999, cost 110 million $Means to AchieveDependability Emergency Shut-down of the Hatch Nuclear Power Plant,Achieving Dependability March 7th, 2008 - Software Update.Quality Attributes Power Outage across Northeastern U.S. and SoutheasternSummary Canada, August 2003, cost 14 billion $ Airplanes crashes such as the American Airlines -Flight 965, Korean Air-Flight 801, Air France- Flight 447. Saleh Al-Da’ajeh Safety-Critical Systems Dependability December 23, 2012 5/16
  6. 6. Safety-Critical Systems Applications Common Characteristics, and Other TerminologiesIntroductionOverviewSafety -Critical SystemsSafety -Critical Systems Safety-critical systems are also known as:Applications, Characteristics,and other Terminologies Real-Time SystemsDependabilityTaxonomy and some times known as "‘Embedded Systems"’ according toThreats on Safety -Critical their existing environment.Systems DependabilityDependability Attributes Different type of safety-critical systems shares four commonMeans to AchieveDependability requirements:Achieving DependabilityQuality Attributes Real-time constraintsSummary Dependability Resources consumption and Long-Operating life. Saleh Al-Da’ajeh Safety-Critical Systems Dependability December 23, 2012 6/16
  7. 7. Safety-Critical Systems Dependability Fundamental Concepts of DependabilityIntroductionOverviewSafety -Critical SystemsSafety -Critical SystemsApplications, Characteristics,and other Terminologies Dependability is the property of a system that deliversDependabilityTaxonomy justifiably services at a reliance level and the ability of theThreats on Safety -CriticalSystems Dependability system to avoid failures that are serious and numerous.Dependability Attributes The concept dependability consists of three main partsMeans to AchieveDependability ThreatsAchieving DependabilityQuality Attributes AttributesSummary Means Saleh Al-Da’ajeh Safety-Critical Systems Dependability December 23, 2012 7/16
  8. 8. Dependability Taxonomy Dependability ExposedIntroductionOverviewSafety -Critical SystemsSafety -Critical SystemsApplications, Characteristics,and other TerminologiesDependabilityTaxonomyThreats on Safety -CriticalSystems DependabilityDependability AttributesMeans to AchieveDependabilityAchieving DependabilityQuality AttributesSummary Figure: Dependability Taxonomy Saleh Al-Da’ajeh Safety-Critical Systems Dependability December 23, 2012 8/16
  9. 9. The Threats: Faults, Error, Failure Faults are further investigated enclosing various aspects such as phase of creationIntroductionOverview or occurence of faults, system boundaries, domain, phenomenological cause, intent,Safety -Critical Systems and presistance of faults.Safety -Critical Systems Failures are discussed covering different aspects such as the domain of the failures,Applications, Characteristics,and other Terminologies controllability of the failures, consistency of the failures, consequences of the failure.DependabilityTaxonomyThreats on Safety -CriticalSystems DependabilityDependability AttributesMeans to AchieveDependabilityAchieving DependabilityQuality AttributesSummary Figure: Relationship between Error, Faults, and Failures Saleh Al-Da’ajeh Safety-Critical Systems Dependability December 23, 2012 9/16
  10. 10. Faults AnalysisIntroductionOverviewSafety -Critical SystemsSafety -Critical SystemsApplications, Characteristics,and other TerminologiesDependabilityTaxonomyThreats on Safety -CriticalSystems DependabilityDependability AttributesMeans to AchieveDependabilityAchieving DependabilityQuality AttributesSummary Saleh Al-Da’ajeh Safety-Critical Systems Dependability December 23, 2012 10/16
  11. 11. Failure AnalysisIntroductionOverviewSafety -Critical SystemsSafety -Critical SystemsApplications, Characteristics,and other TerminologiesDependabilityTaxonomyThreats on Safety -CriticalSystems DependabilityDependability AttributesMeans to AchieveDependabilityAchieving DependabilityQuality AttributesSummary Saleh Al-Da’ajeh Safety-Critical Systems Dependability December 23, 2012 11/16
  12. 12. Attributes According to the Larpie and /ISO 9126IntroductionOverview Dependability consists of a subset of quality attributes that can be classified intoSafety -Critical Systems run-time quality attributes, and non-run time quality attributes:Safety -Critical SystemsApplications, Characteristics,and other Terminologies Run-time AttributesDependability Availability: readiness of service for authorized usersTaxonomy Reliability: continuity of service. The system is expected toThreats on Safety -CriticalSystems Dependability perform its task in spite of the existence of some faults.Dependability Attributes Integrity: non-occurrence of improper alternation ofMeans to Achieve information.Dependability Confidentiality: non-occurrence of unauthorized disclosure ofAchieving DependabilityQuality Attributes information as system data and programs are resistant to unauthorized modifications.Summary Safety: non-occurrence of catastrophic consequences for the user(s) and in the operation environment. Non Run-time attributes: Maintainability: aptitude to undergo repairs and evolution Saleh Al-Da’ajeh Safety-Critical Systems Dependability December 23, 2012 12/16
  13. 13. Achieving Dependability Quality Attributes Verification, Validation, and EngineeringIntroductionOverviewSafety -Critical SystemsSafety -Critical Systems The oldest methods, approaches, and techniques undertakenApplications, Characteristics,and other Terminologies to achieve dependability quality attributes are nowadaysDependability depicted as verification and validation activities; falling intoTaxonomyThreats on Safety -Critical the software testing stage.Systems DependabilityDependability Attributes The very recent mechanisms undertaken to achieve theMeans to Achieve various dependability quality attributes are focused onDependabilityAchieving Dependability engineering quality attributes at the early stages, such asQuality Attributes balancing the quality attributes relationships by utilizing theSummary most suitable architectural strategies and patterns for the software systems. Saleh Al-Da’ajeh Safety-Critical Systems Dependability December 23, 2012 13/16
  14. 14. Means to Achieve Dependability to Safety -Critical SystemsIntroductionOverviewSafety -Critical Systems Although dependability quality attributes achievement isSafety -Critical SystemsApplications, Characteristics, strongly related to the software architecture stage, yetand other Terminologies almost all the means undertaken to achieve dependabilityDependabilityTaxonomy quality attributes are usually left to be used in late stages ofThreats on Safety -CriticalSystems Dependability the software development life-cycle.Dependability Attributes Attaining dependability quality attributes is never isolatedMeans to AchieveDependability to a distinct stage nor a certain technique/approach.Achieving DependabilityQuality Attributes Means adopted by dependability engineers are as follow:Summary Fault Prevention Fault Tolerance Fault Removal Fault Forecasting Saleh Al-Da’ajeh Safety-Critical Systems Dependability December 23, 2012 14/16
  15. 15. Is the solution to give up on our use of software for such purposes altogether?!IntroductionOverviewSafety -Critical SystemsSafety -Critical SystemsApplications, Characteristics, Recent decades bear testimony to how we have gone fromand other Terminologies merely using software , to rely on it, and to ultimatelyDependabilityTaxonomy becoming dependent on it, for our day to day lives.Threats on Safety -CriticalSystems Dependability Better engineering, testing, and practices are needed to beDependability Attributes implemented, and this is especially true of software that isMeans to AchieveDependability related to safety-critical systems.Achieving DependabilityQuality Attributes Software engineering, and related curriculum at educationalSummary institution should be updated to reflect the every growing importance of software safety as a field. Saleh Al-Da’ajeh Safety-Critical Systems Dependability December 23, 2012 15/16
  16. 16. Thank you all for attending this seminar. Questions are most welcomed !
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×