Developing a business critical system can involve considerable difficulties. This paper describes part of a new methodology that tackles this problem using co-evolution of models and prototypes to strengthen the relat...
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Developing a business critical system can involve considerable difficulties. This paper describes part of a new methodology that tackles this problem using co-evolution of models and prototypes to strengthen the relationship between modelling and testing. We illustrate how different modelling frameworks, Promela/SPIN and B/ProB/AtellerB, can be used to implement this idea. As a way to reinforce integration between modelling and testing we use model-based tests and trace-driven model checking. As a result we were able to anticipate problems and guide the development of our software in a safer way, increasing our understanding of the system and its reliability.
With computersystems becoming ever larger and more complex, the cost and effort associated with their construction is increasing and the systems are now sufficiently complex that developers need help to analyse and u...
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With computersystems becoming ever larger and more complex, the cost and effort associated with their construction is increasing and the systems are now sufficiently complex that developers need help to analyse and understand them. However, at design time, when this understanding is crucial, the system is unavailable because it has yet to be built. Formal, executable models can help with this problem by providing developers with a platform on which to establish the feasibility of a proposed design. However, commercial developers seem reluctant to employ this type of modelling in their design activity. This paper describes a modelling tool in which the traditional model generation technique of writing "programming language like" code is replaced with a model generation tool which uses a graphical representation of models whilst retaining sufficient formality to permit the models to be executed, or converted into code for analysis by a traditional model checking tool.
As every information system becomes connected to every other information system, they form the so-called "information utility". This is the domain in which contemporary distributed systems have to operate. N...
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As every information system becomes connected to every other information system, they form the so-called "information utility". This is the domain in which contemporary distributed systems have to operate. New applications have to be evolved on this platform of existing systems that may hold inconsistent information. Consequently, solutions need to be able work in a world of only partially correct information. In this paper, we discuss means whereby architects, designers and engineers may, in this context of information inconsistency, develop new business solutions and reason about their validity. In particular we describe the properties of inter-enterprise system architectures for applications working with partially replicated and partially consistent information. These must be able to operate under reversible assumptions and to undo operations as a consequence of reversing assumptions. We have developed exemplary architectures that exhibit these properties, used them to investigate the concept of inconsistency-tolerant components and begun to devise methods of building inter-enterprise applications from such components. This approach, we conjecture, makes reasoning about the validity of proposed inter-enterprise scale solutions more straightforward and thus increases the speed with which new solutions can be deployed. We are evaluating these ideas now, by building, along with our industrial collaborators, realistic enterprise-scale demonstrations in the domains of Finance and Defence.
Formal methods are a nice idea, but the size and complexity of real systems means that they are impractical. We propose that a reasonable alternative to attempting to specify and verify the system in its entirety is t...
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Formal methods are a nice idea, but the size and complexity of real systems means that they are impractical. We propose that a reasonable alternative to attempting to specify and verify the system in its entirety is to build and evaluate an abstract model(s) of aspects of the system that are perceived as important. Using a model will not provide proof of the system, but it can help to find shortcomings and errors at an early stage. Executing the model should also give a measure of confidence in the final product. Many systems today are built from communicating components so that the task of the developers is becoming fitting these components together to form the required system. We show how a formal model can be sympathetic to this type of architecture using our tool, RolEnact and explain how this may be related to a COM implementation.
There is a continuing need for software engineers to design better-quality systems more quickly. Component-based technologies promise to make this possible, but modern systems are too complex for a full analysis of th...
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There is a continuing need for software engineers to design better-quality systems more quickly. Component-based technologies promise to make this possible, but modern systems are too complex for a full analysis of their behaviour to be practical. We propose that a reasonable alternative is to analyse abstract models of the essential features of a system. Since these models are abstract, they need contain only those details that are relevant to the aspect of the system under consideration. Consequently, they can be small enough to be constructed quickly and analysed thoroughly using formal methods. Tools are required which are accessible to the novice but which remain powerful enough to build models with a formal foundation so that they can be used by system designers who have limited expertise in the use of formal methods. We propose our tool, RolEnact, as a candidate for this role.
Repetitive, or multipass, processes are a class of 2D systems of both practical and algorithmic/theoretical interest whose dynamics cannot be analysed or controlled using standard (1D) systems theory. Recently it has ...
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Repetitive, or multipass, processes are a class of 2D systems of both practical and algorithmic/theoretical interest whose dynamics cannot be analysed or controlled using standard (1D) systems theory. Recently it has ...
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Repetitive, or multipass, processes are a class of 2D systems of both practical and algorithmic/theoretical interest whose dynamics cannot be analysed or controlled using standard (1D) systems theory. Recently it has been shown that the modelling of the boundary conditions, also known as the process initial conditions, is a crucial feature in the analysis and control of these processes. This paper presents some further results on the effects of so-called 'dynamic' process initial conditions on the controllability and stability properties of discrete linear repetitive processes. Previous work has shown that these dynamic process initial conditions alone can destroy the stability properties of these processes. Hence their effects must be 'adequately' accounted for the process modelling stage in order to ensure that subsequent analysis does not lead to incorrect results/conclusions. The main results developed in this paper can be summarised as follows. (i) Computationally efficient stability tests which can, in effect, be applied using standard, or 1D, linear systems tests. (ii) Characterisation of so-called pass controllability in the form of matrix rank based conditions. (iii) Conditions under which the dynamic process initial conditions can be selected to ensure stability and pass controllability.
Repetitive, or multipass, processes are a class of systems characterised by a series of sweeps through a set of dynamics defined over a finite fixed duration. The class of so-called discrete linear repetitive processe...
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ISBN:
(纸本)9783952426906
Repetitive, or multipass, processes are a class of systems characterised by a series of sweeps through a set of dynamics defined over a finite fixed duration. The class of so-called discrete linear repetitive processes have strong structural links with well studied classes of 2D linear systems and also with standard (1D) linear systems. One possible approach to the (control related) analysis of these processes is to embed their basic 2D structure in a 1D representation. This paper develops such a representation and uses it to characterise the key systems theoretic property of controllability for this class of linear repetitive processes.
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