Table Of ContentSpringer Series in Reliability Engineering
For furthervolumes:
http://www.springer.com/series/6917
Ajit Kumar Verma Srividya Ajit
• •
Manoj Kumar
Dependability of Networked
Computer-based Systems
123
Prof.Ajit KumarVerma Dr. ManojKumar
Department of ElectricalEngineering System EngineeringSection
Indian Instituteof TechnologyBombay ControlInstrumentationDivision
(IITB) Bhabha Atomic Research Centre (BARC)
Powai, Mumbai400076 Trombay, Mumbai400085
India India
e-mail: akvmanas@gmail.com e-mail: kmanoj@barc.gov.in
Prof.Srividya Ajit
Department of CivilEngineering
Indian Instituteof TechnologyBombay
(IITB)
Powai, Mumbai400076
India
e-mail: asvidya@civil.iitb.ac.in
ISSN 1614-7839
ISBN 978-0-85729-317-6 e-ISBN978-0-85729-318-3
DOI 10.1007/978-0-85729-318-3
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Dedicated to
Our Parents
Sri Kedar Prasad Verma & Smt Sushila Verma
Sri B.C. Khanapuri & Smt Vibhavati B. Khanapuri
Sri Gayanand Singh & Smt Droupdi Devi
Our Gurus
Bhagwan Sri Sathya Sai Baba
Paramhansa Swami Sathyananda Saraswati
Sri B. Jairaman & Smt Vijaya Jairaman
Dr. C.S. Rao & Smt Kasturi Rao
Our Teachers
Prof.A.S.R.Murthy(ReliabilityEngg.,IITKharagpur)
Prof.M.A.Faruqi(MechanicalEngg.,IITKharagpur)
Prof. N.C. Roy (Chemical Engg., IIT Kharagpur)
Foreword
A compelling requirement in today’s context of the prevalent use of complex
processes and systems in process and service industries, military applications,
aerospace automotive and transportation, logistic, and other, is to maintain high
dependability and security. The first casualty of integrated real time complex
systems is dependability owing to an combinatorial like explosion of possible
states, some with unacceptable probability levels and many unsafe states as well.
The theoretical foundation for analytical treatment of such systems is crucial to
their understanding, design and implementation. This book aims to explore the
analysis, simulation and limitations in the implementation of such complex sys-
tems, addressing a multitude of issues and challenges in the application of com-
puter-based systems in dependability and safety critical applications. In my
opinion, this book is exceptional as it fulfills a long felt need of engineers,
scholars, researchers and designers for a coherent, yet effective and efficient
treatmentofsuchsystemsandproblems,builtupwithaconceptualhierarchythat
starts from the basics.
The real-time systems also need to have an extremely important characteristic
feature,timeliness.Mostofthecontemporaryresearchworkfocusesonworst-case
timing guarantees. A probabilistic measure of timeliness is the new buzzword in
the dependability community. A highlight of this book is its emphasis on the
probabilistic measures of dependability and timeliness. System designers usually
face several problems while choosing an appropriate technology (in particular, a
network)foragivenproject.Thederivationofatimelinesshazardrateenablesan
integrated dependability modeling of the system which in turn helps the system
designer in making decisions based on specific requirements and uniform mea-
sure(s).Thisbookcontainssomedetailed,wellexplainedandintuitivelyappealing
examples which the practitioner may find directly applicable in the analysis and
solution of his or her problems.
I wish to congratulate the authors for their endeavors in bringing forth such a
timely and insightful book on the dependability of networked computer-based
systems. Their deep knowledge of the area, combined with vision concerning the
presentandfuturechallenges,haveledtothisremarkablebook.Iamsurethatthis
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viii Foreword
book will serve as an invaluable guide for scholars, researchers and practitioners
interested and working in the field of critical applications where reliance on
automation is indispensable.
October 2010 Academician Janusz Kacprzyk
Professor, Ph.D., D.Sc., Fellow of IEEE, IFSA
President of the Polish Society for Operational
and Systems Research, Immediate Past President
of IFSA (International Fuzzy Systems
Association), Systems Research Institute,
Polish Academy of Sciences,
Warsaw, Poland
Preface
Thisbookismeantforresearchscholars,scientistsandpractitionersinvolvedwith
the application of computer-based systems in critical applications. Ensuring
dependability of systems used in critical applications is important due to the
impactoftheirfailuresonhumanlife,investmentandenvironment.Theindividual
aspects of system dependability—reliability, availability, safety, timeliness and
securityarethefactorsthatdetermineapplicationsuccess.Toanswerthequestion
onrelianceoncomputersincriticalapplications,thisbookexplorestheintegration
of dependability attributes within practical, working systems. The book addresses
the growing international concern for system dependability and reflects the
important advances in understanding how dependability manifests in computer-
based systems.
Probability theory, which began in the seventeenth century is now a well-
established branch of mathematics and finds applications in various natural and
social sciences, i.e. from weather predictionto predictingthe riskof new medical
treatments.Thebookbeginswithanelementarytreatment ofthebasic definitions
and theorems that form the foundation for the premise of this work. Detailed
informationonthesecanbefoundinthestandardbooksonprobabilitytheoryand
stochastic theory, for a comprehensive appraisal. The mathematical techniques
used have been kept aselementaryas possibleand Markov chains, DSPN models
and Matlab code are given where relevant.
Chapter 1 begins with an introduction to the premise of this book, where
dependabilityconceptsareintroduced.Chapter2providestherequisitefoundation
on the essentials of probability theory, followed by introduction to stochastic
processesandmodelsinChap.3.Variousdependabilitymodelsofcomputer-based
systemsarediscussedinChap.4.Markovmodelsforthesystemsconsideringsafe
failures, perfect and imperfect periodic proof tests, and demand rate have been
derived. Analysis has been done to derive closed form solution for performance-
based safety index and availability.
In Chap. 5, medium access control (MAC) protocol mechanisms of three
candidate networks are presented in detail. The MAC mechanism is responsible
for the access to the network medium, and hence effects the timing requirement
ix
x Preface
ofmessagetransmission.Acomparisonofnetworkparametersisalsopresentedto
provide an understanding of the various network protocols that can be used as
primary guidelines for selecting a network solution for a given application.
Methods to probabilistically model network induced delay of two field bus
networks, CAN, MIL-STD-1553B and Ethernet are proposed in Chap. 6. Hazard
rates are derived from discrete time process for a fault tolerant networked com-
putersystem.Modelsarederivedforthethreedependabilityattributes—reliability,
availability and safety, of NRT systems in Chap. 7. Timeliness hazard rate is
modeled as reward rate.
We hopethisbookwillbeaveryusefulreferencefor practicingengineersand
research community alike in the field of networked computer-based systems.
Mumbai, October 2010 Ajit Kumar Verma
Srividya Ajit
Manoj Kumar
Acknowledgments
We are indebted to Department of Electrical Engineering & Department of Civil
Engineering, IIT Bombay and Control Instrumentation Division, BARC for their
encouragement and support during the project.
Manyofourfriends,colleaguesandstudentscarefullywentthroughdraftsand
suggestedmanychangeschangedimprovingthereadabilityandcorrectnessofthe
text. Many thanks to Shri U. Mahapatra, Shri G.P. Srivastava, Shri P.P. Marathe,
ShriR.M.SureshBabu,ShriM.K.Singh,Dr.GopikaVinod,Prof.VivekAgarwal,
Prof. Varsha Apte and Prof. P.S.V. Nataraj for their suggestions. The help by
publishingstaff,especiallyofMr.Claire,intimelypreparationofthebookisalso
appreciated.
Mumbai, October 2010 Ajit Kumar Verma
Srividya Ajit
Manoj Kumar
xi