Using eventb method to model routing information protocol. We present a formal development in event b of a distributed topology discovery algorithm. This method is based on refinement and proof obligations, which ensures a strong assurance of. Itt extends the usage of b to systems that might contain software but also hardware and pieces of equipment.
It includes tool support and has been used in some significant industrial applications e. We strive to help students to build skills on formal methods that they can employ later on in their future it jobs in software. This chapter relates the experience of cswt with eventb in the context of deploy, describing the advantages of this formal method for safety and. Formal specification in eventb alexander serebrenik, ulyana tikhonova.
This method is based on refinement and proof obligations, which ensures a strong assurance of bugs. For sequential software, examples of formal methods include the bmethod, the specification languages used in automated theorem proving, raise. In event b, a system is developed as sequence of models. It is a development of the bmethod, produced as part of the collaborative european rodin project rigorous open development environment for complex systems.
The mathematical language and the proof method of event b are introduced. B is related to the z notation also originated by abrial and supports development of programming language code from. Our method of refinement based formal modelling, baseline compliance testing of the model and coverage driven test extraction using the single language of eventb is a new way to address a key challenge facing the design and verification of multicore systems. B is a formal method for the development of program code from a specification in the abstract machine notation. System and software engineering provides a comprehensive exposition of the event b approach for modeling and reasoning about systems. This method use proof obligations rules which based on mathematical approach to.
A eventb formal verification method used to model and verify zigbee protocol stack by providing embedding of the protocol primitives in eventb 24. Comp2214 advanced software modelling and design module overview this module builds on the part 1 software modelling and design course by looking at structured requirements engineering in more detail, by addressing scaling of formal modelling with eventb through refinement and also looking at verification techniques for models and for programs. Questions tagged formal methods ask question formal methods are a particular kind of mathematicallybased techniques for the specification, development and verification of software and hardware systems. It uses the notion of refinement step by step modeling, going from an abstract level and add more details gradually to move on to a more concrete one.
Avocs 2006 a method to refine time constraints in event b. The approach takes advantage of the eventb method capabilities to model designs at different levels of abstraction which fits the layered nature of the protocol. Information and translations of bmethod in the most comprehensive dictionary definitions resource on the web. Event b is a notation and method developed from the b method and is intended to be used with an incremental style of modelling. The rodin tool is a tool for formal modelling in event b. I shall give some insights on modeling and formal reasoning, activities intended to be performed before undertaking the actual coding of a computer system, so that the software in question will be correct by construction. The same goes if youre currently working at, or know a company that uses formal methods but is not on the list. Towards sophisticated air traffic control system using formal. It was originally developed by jeanraymond abrial in france and the uk. Eventb has been influenced by the work done earlier on action systems by the finnish school action system however remained an academic project.
Formal specification in event b alexander serebrenik, ulyana tikhonova 2iw80 software specification and architecture. It deals with system and software modeling in eventb, a language issued from the b method and allowing the description of systems with events. We report challenges we have faced during the past 10 to 15 years when teaching formal methods using the event b formalism, and describe how we have evolved the structure of our courses to respond to those challenges. An essential di erence between eventb and the b method is that eventb admits a richer notion of re nement in which new.
Event b is a formal method for systemlevel modelling and analysis. It has simple concepts within which a complex and discrete system can be modelled. Introducing formal methods formal methods for software specification and analysis. This method is based on refinement and proof obligations, which ensures a strong assurance of bugs absence 12. The use of formal methods approaches can help to eliminate errors early in the design process. These tests can then be used for extensive regression testing of hardware and software systems. Facilitating construction of safety cases from formal models. The archive contains the event b development for the water tank system.
Eventbased formalization of safetycritical operating system. The b method event b 11 48 introduction events an event without guards has the following form. Event b is the synthesis between b and action system. Pdf using the eventb formal method for disciplined agile. We illustrate the method by defining models for three simple control systems sluice gate, traffic light, package router and by characterizing eventb machines as a specific class of asms. Comp2214 advanced software modelling and design module overview this module builds on the part 1 software modelling and design course by looking at structured requirements engineering in more detail, by addressing scaling of formal modelling with event b through refinement and also looking at verification techniques for models and for programs. Abstracteventb is a formal method used for software development, in complex system. Formal methods are best described as the application of a fairly broad variety of theoretical computer science fundamentals, in particular logic calculi, formal languages, automata theory, discrete event dynamic system and program semantics, but also type systems and algebraic data types to problems in software and hardware specification and. A list of companies that use formal verification methods in software engineering.
Feb 17, 2020 a list of companies that use formal verification methods in software engineering. The main controller has a process model of the door subsystem. Formal specification in eventb alexander serebrenik, ulyana tikhonova 2iw80 software specification and architecture. Key features of eventb are the use of set theory as a modeling notation, the. In that respect, one of the outcome of event b is the proved definition of systems architectures and, more.
In eventb, a system is developed as sequence of models. An overview l 5 2 software engineering and formal methods nevery software engineering methodology is based on a recommended development process proceeding through several phases. In this paper i will introduce the ideas behind the b formal method, especially as crystalised in its latest version, event b. Introduction in todays digital era, businesses are facing a challenge of releasing commercial software projects of quality on time and within budget. Christian attiogbe november 2008, maj 1120 the b method event b 1 48. In this paper i will introduce the ideas behind the b formal method, especially as crystalised in its latest version, eventb. The approach takes advantage of the event b method capabilities to model designs at different levels of abstraction which fits the layered nature of the protocol. Mike hinchey formal methods formal methods are mathematically based techniques for specification, development and verification of systems, both hardware and software. Introduction abstract system or a model, or a machine. Event b here, we provide a brief overview of event b.
System and software engineering by jeanraymond abrial. The method and the supporting toolset called rodin were further developed and applied in industry in the collaborative european deploy integrated project industrial. Distributed topology discovery is at the core several routing algorithms and is the problem of each node in a network discovering and maintaining information on the network topology. Critical software technologies experience with formal methods. This platform is based on the eventb formal method and provides natural support for refinement and mathematical proof. In this white paper, we show that several formal methods b, eventb, formal data validation directly contribute to safety critical software development, systemlevel sprecification analysis and constant parameters validation, with. It is a development of the b method, produced as part of the collaborative european rodin project rigorous open development environment for complex systems. This platform is based on the event b formal method and provides natural support for refinement and mathematical proof. The event b method is used to build reliably systems using discrete system models and aims at obtaining systems which can be considered to be correct by construction, in the sense that the systems produced are guar. System and software engineering provides a comprehensive exposition of the eventb approach for modeling and reasoning about systems. Key features of eventb are the use of set theory as a modelling notation, the use of refinement to represent systems at different abstraction levels and the use of mathematical proof to verify consistency between refinement levels.
It was originally developed in the 1980s by jeanraymond abrial 1 in france and the uk. Formal design of scalable conversation protocols using event. A formal, systematic approach to stpa using eventb refinement and proof 237 3. This chapter relates the experience of cswt with event b in the context of deploy, describing the advantages of this formal method for safety and missioncritical systems and the lessons learned. Formal modelling, testing and verification of hsa memory. The mathematical language and the proof method of eventb are introduced. For sequential software, examples of formal methods include the b method, the specification languages used in automated theorem proving, raise. It was originally developed in the 1980s by jeanraymond abrial in france and the uk. The bmethod has been developed by jeanraymond abrial also originator of the z notation and others. The project introduced a formal method, event b, into several industrial organisations and built on the lessons learned to provide an ecosystem of better tools, documentation and support to help. The formal method used in our work is eventb 5 which is extended from bmethod 2. A formal, systematic approach to stpa using eventb. More information about the book is at cambridge university press website the event b introduced in abrials book in some ways differs from the event b implemented by rodin.
Sep 30, 20 jeanraymond abrials eventb book has been published in may 2010. Formal methods and software engineering springerlink. Open tool platform for the cost effective rigorous development of dependable complex software systems services. Sep 10, 2018 v the b method development of the z language is a method of software development based on an abstract machine notation used in the development of computer software b language. More information about the book is at cambridge university press website the eventb introduced in abrials book in some ways differs from the eventb implemented by rodin. We show in this short paper the general method used to deal with time constraints with a simple application example. Software safety assurance standards, such as do178c allows the usage of formal methods through supplementation, and common criteria mandates formal methods at the highest levels of categorization.
These tests are used for extensive regression testing of hardware and software systems. We present a formal development in eventb of a distributed topology discovery algorithm. More information about the book is at cambridge university press website. B method to prove that each cp constructed using our operators is realizable. Modeling in eventb a practical text suitable for an introductory or advanced course in formal methods, this book presents a mathematical approach to modeling and designing systems using an extension of the b formalism. B is related to the z notation also originated by abrial and supports development of programming language code from specifications. The draft paper outlines an approach to treating continuous behaviour in event b by a discrete approximation. In this work, realizability is guaranteed by construction. Christian attiogbe november 2008, maj 1120 the b method event b 12 48. The b method is a method of software development based on b, a toolsupported formal method based on an abstract machine notation, used in the development of computer software. Jeanraymond abrials eventb book has been published in may 2010. We illustrate the method by defining models for three simple control systems sluice gate, traffic light, package router and by characterizing event b machines as a specific class of asms. Eventb is a formal method for systemlevel modelling and analysis. The abz conference is dedicated to the crossfertilization of statebased and machinebased formal methods, like abstract state machines asm, alloy, b, tla, vdm and z, that share a common conceptual foundation and are widely used in both academia and industry for the design and analysis of hardware and software systems.
This applies for event b formal method which does not have specific notions for time and uses the refinement to introduce it. The method and the supporting toolset called rodin were further developed and applied in industry in the collaborative european deploy. Key features of event b are the use of set theory as a modelling notation, the use of refinement to represent systems at different abstraction levels and the use of mathematical proof to verify consistency between refinement levels. Key features of eventb are the use of set theory as a modeling notation, the use of re. The project introduced a formal method, eventb, into several industrial organisations and built on the lessons learned to provide an ecosystem of better tools, documentation and support to help. This formal method provides a framework in which people can describe, develop, and validate systems in a systematic manner. If you see a company on the list that doesnt exist anymore, or does not use formal methods anymore, please send a pull request with an explanation. The idea of incremental modelling has been taken from programming.
Eventb 16,20 is a statebased formal method for system level modelling and veri. In this paper, we show how our approach applies and scales to a set of use cases borrowed from the literature and used by the research community. Evaluation of a guideline by formal modelling of cruise. The event b introduced in abrials book in some ways differs from the event b implemented by rodin. The main reasons for choosing eventb are rstly that it is the language used in the cookbook and secondly. The eventb method is used to build reliably systems using discrete system models and aims at obtaining systems which can be considered to be correct by construction, in the sense that the systems produced are guar. Dec 27, 2019 eventb is a formal method for systemlevel modeling and analysis. The b method event b formal software construction j. Eventb is a notation and method developed from the bmethod and is intended to be used with an incremental style of modelling. An essential di erence between event b and the b method is that event b admits a richer notion of re nement in which new.
Eventb is a formal method for systemlevel modeling and analysis. Formal methods are defined as in encyclopedia of software engineering. Eventb here, we provide a brief overview of eventb. The rodin tool is a tool for formal modelling in eventb. A more widely scope use of b appeared in the mid 90s, called eventb, to analyze, study and specify, not only software, but also whole systems see abrial 05. An example of a water tank system is used to illustrate the proposed approach. Using the eventb method for critical systems axons medium.
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