Revision of CTL Models

Guerra, Paulo T.; Wassermann, Renata

doi:10.1007/978-3-642-16952-6_16

Cited by 8 publications

(4 citation statements)

References 10 publications

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“…Each of these three cases expresses a form of inconsistency between bases. Automatic techniques for inconsistency checking of systems are available both through theorem proving and model checking, also within the AGM paradigm, and widely reported in the literature, [33,13,50,54,30]. Formal operations can be dened on S i so that either the current input in the implementation becomes valid for the model; or the specication that makes our current input invalid is removed; or the order of the base is changed, in combination with the other operations.…”

Section: Change Operationsmentioning

confidence: 99%

A theory of change for prioritised resilient and evolvable software systems

2019

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The process of completing, correcting and prioritising specications is an essential but very complex task for the maintenance and improvement of software systems. The preservation of functionalities and the ability to accommodate changes are main objectives of the software development cycle to guarantee system reliability. Logical theories able to fully model such processes are still insucient. In this paper we propose a full formalisation of such operations on software systems inspired by the AGM (Alchourrón-Gärdenfors-Makinson) paradigm for belief revision of human epistemic states. We represent specications as nite sets of formulas equipped with a priority relation that models functional entrenchment of properties. We propose to handle specication incompleteness through ordered expansion, inconsistency through ordered safe contraction and prioritisation through revision with reordering, and model all three in an algorithmic fashion. We show how the system satises basic properties of the AGM paradigm, including Levi's and Harper's identities. We oer a concrete example and complexity results for the inference and model checking problems on revision. We conclude by describing resilience and evolvability of software systems based on such revision operators.

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Section: Change Operationsmentioning

confidence: 99%

A theory of change for prioritised resilient and evolvable software systems

2019

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“…In [7], model repair is applied to the fault recovery of component-based models. Finally, a slightly different but also related problem is that of Model Revision, which has been studied for UNITY properties in [8,9] and for CTL in [36]. Other methods in the area of fault-tolerance include the work in [30], which uses discrete controller synthesis and [29], which employs SMT solving.…”

Section: Related Workmentioning

confidence: 99%

Abstract Model Repair

Chatzieleftheriou¹,

Bonakdarpour²,

Katsaros³

et al. 2015

Logical Methods in Computer Science

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Abstract. Given a Kripke structure M and CTL formula φ, where M does not satisfy φ, the problem of Model Repair is to obtain a new model M such that M satisfies φ. Moreover, the changes made to M to derive M should be minimum with respect to all such M . As in model checking, state explosion can make it virtually impossible to carry out model repair on models with infinite or even large state spaces. In this paper, we present a framework for model repair that uses abstraction refinement to tackle state explosion. Our framework aims to repair Kripke Structure models based on a Kripke Modal Transition System abstraction and a 3-valued semantics for CTL. We introduce an abstract-model-repair algorithm for which we prove soundness and semi-completeness, and we study its complexity class. Moreover, a prototype implementation is presented to illustrate the practical utility of abstract-model-repair on an Automatic Door Opener system model and a model of the Andrew File System 1 protocol.

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“…They proposed a set of ve primitive change operations to modify a model and dene an admissible minimal change criteria. Nonetheless, as pointed by Guerra and Wassermann (2010), model update can lead to signicant loss of information in some cases, and it is argued that AGM belief revision presents a suitable apparatus to revise models in static contexts where the requirements do not change, but the model that does not cope with its own specication is revised. Guerra (2016) has discussed two main aspects involving AGM paradigm regarding temporal logics.…”

Section: Belief Change In Formal Methodsmentioning

confidence: 99%

Belief change without compactness

Ribeiro¹

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One of the main goals of Articial Intelligence (AI) is to build rational agents that are capable of taking rational decisions autonomously. For this, it is essential to devise mechanisms to properly represent knowledge, and reason about the knowledge that an agent has about the world. However, an agent's knowledge is not static-it gets updated as the agent acquires new information. One of the big challenges involving knowledge representation is how an agent ought to change its own knowledge and beliefs in response to any new information it acquires. This, in short, is the problem of belief change. Standard approaches of Belief Change come in two avours: a set of rationality postulates that prescribes epistemic behaviours for an agent, and a collection of constructions, or functions, to perform such rational changes. The two foremost paradigms of Belief Change are the AGM paradigm (for belief change in a static environment) and the KM paradigm (for belief change in a dynamic environment). Both these paradigms make strong assumptions about the underlying logic used to express an agent beliefs, such as Supraclassicality and Compactness. Relying on these assumptions, however, is rather restrictive, since many logics that are important for both AI and Computer Science applications do not have them. This thesis focuses on extending Belief Change to the realm of non-compact logics. One of the side eects of dispensing with compactness is that standard constructions of both the AGM and the KM paradigms no longer nicely connect with the respective rationality postulates. In this work, I identify the reasons behind this breakdown. This in turn helps us identify some minimal conditions under which the existence of rational AGM and KM belief change operations is guaranteed. Subsequently we provide constructive accounts of AGM-and KM-rational belief change operations without the compactness assumption, and we oer full accounts of belief change for both the paradigms. The main dierence of our approach from the standard ones relies on the way epistemic preference of an agent is represented: instead of remainders and Grove's Systems of Spheres, we consider maximal complete theories and genuine partial relations over worlds. Furthermore, we also consider the connection between AGM revision and non-monotonic reasoning (NMR) systems, often viewed to be two sides of the same coin. We demonstrate that the bridge between belief revision and NMR breaks down in the absence of compactness. We then identify the basis of this breakdown, and present a new non-monotonic system that appropriately connects with the AGM revision postulates even in absence of compactness. Signicantly, this connection with the AGM paradigm is independent of any specic constructions (such as systems of spheres), and is directly established between the AGM postulates and the axioms of the proposed non-monotonic system.

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Revision of CTL Models

Cited by 8 publications

References 10 publications

A theory of change for prioritised resilient and evolvable software systems

A theory of change for prioritised resilient and evolvable software systems

Abstract Model Repair

Belief change without compactness

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