Enabling Reasoning and Veriﬁcation Support for Intelligent Agent Systems, using Formal Methods

Ξύστρα, Αικατερίνη

dc.contributor.author	Ξύστρα, Αικατερίνη	el
dc.date.accessioned	2018-03-23T12:01:15Z
dc.date.available	2018-03-23T12:01:15Z
dc.date.issued	2018-03-23
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/46767
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.2900
dc.rights	Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/gr/	*
dc.subject	intelligent agents	en
dc.subject	formal methods	en
dc.title	Enabling Reasoning and Veriﬁcation Support for Intelligent Agent Systems, using Formal Methods	en
heal.type	doctoralThesis
heal.secondaryTitle	Ανάλυση και Επαλήθευση της συμπεριφοράς έξυπνων πρακτόρων με τη χρήση τυπικών μεθόδων	el
heal.secondaryTitle	Ανάλυση και Επαλήθευση της συμπεριφοράς έξυπνων πρακτόρων με τη χρήση τυπικών μεθόδων	el
heal.classification	COMPUTER SCIENCE	en
heal.classificationURI	http://data.seab.gr/concepts/77de68daecd823babbb58edb1c8e14d7106e83bb
heal.language	en
heal.access	campus
heal.recordProvider	ntua	el
heal.publicationDate	2017-12-12
heal.abstract	"Formal methods are techniques, languages and tools based on mathematics, which provide an unambiguous, strict mathematical description or speciﬁcation which is used for eﬀective design, analysis and veriﬁcation of desired properties of the system. An important branch of formal methods are algebraic speciﬁcation languages with a rigorous basis on mathematical logical systems or combinations of them. Such a language is CafeOBJ, an executable, new generation algebraic speciﬁcation language, member of the OBJ family languages. Its main characteristic, that diﬀerentiates it from other formalisms, is its direct support to behavioural speciﬁcation paradigm since it embeds special hidden sorts and behavioural operators in its syntax. Behavioural speciﬁcation is based on hidden algebra and supports an object oriented style of algebraic speciﬁcation. It also supports speciﬁcation of distributed complex systems as abstract state machines and veriﬁcation of safety properties of them through theorem proving techniques such as simultaneous induction and coinduction. The scope of the thesis is the modelling and veriﬁcation of intelligent agents using algebraic speciﬁcation techniques. By intelligent agents we refer to the systems used in the New or Semantic Web in order to achieve the need for reactivity, interaction and communication between its various components. An intelligent agent can be deﬁned as an autonomous entity which observes through sensors and acts upon an environment using actuators (i.e. it is an agent) and directs its activity towards achieving goals. Due to the special characteristics of such systems, and their increased development as well as their use in critical domains, the requirements for reliability, security and proper functionality has led to the use of formal methods for their analysis and the development of new methodologies oriented to these systems. To this end, in this thesis an algebraic framework is proposed for the speciﬁcation and veriﬁcation of two basic types of intelligent systems, those whose behaviour is expressed in terms of reactive rules (reactive rule-based systems) and those who can sense the changes in their physical environment (context-aware systems), and adapt their behaviour accordingly. In the ﬁrst category of intelligent agents, we ﬁrst give formal semantics, based on the hidden algebra formalism, to the basic reactive rule families, then we formally analyse and verify reactive rule-based systems using equational logic, next we propose the use of rewriting logic for the detection of structural errors of the rules, such as termination and conﬂuence, and ﬁnally we compare the proposed approaches. In the second type of agents, which are usually more complex, the speciﬁcation of the system, is deﬁned as the composition of the speciﬁcations of 3 its components, i.e. the speciﬁcations which describe data types as visible sorts and the various components of the system as Observational Transition Systems, a kind of behavioural object. In this way the complex interactions of such systems can be expressed in a natural and dynamic way. Based on the speciﬁcation, veriﬁcation of properties of the intelligent system using theorem proving techniques is also feasible. The fact that the system is speciﬁed as a transition system, using equational or rewriting logic, makes the method easier to read, understand and learn than other related methods, which prerequisite deeper knowledge of theorem proving, or that are based in higher order logic for example. To demonstrate the applicability and eﬀectiveness of the proposed methodologies, a number of case studies are conducted. Security aspects of intelligent systems are of major importance, and it was inevitable to take them into account. To this end we present the veriﬁcation of the behaviour of various intelligent systems from the literature. In the last section of the thesis, an extension of the speciﬁcation and veriﬁcation methodology, supported by the CafeOBJ language, is proposed that provides more automation for the proofs and allows the use of more conventional veriﬁcation tools, by integrating it with the Athena automated theorem proving system. The proposed methodology is based on the interaction of the two languages so as to be able to exploit the nice properties of each method and thus have better results in the veriﬁcation process. Finally, a number of applications of the methodology in protocols that are often used as case studies, especially for tools dedicated to the veriﬁcation of complex systems, are presented.	en
heal.sponsor	This research has been co-ﬁnanced by the European Union (European Social Fund – ESF) and Greek national funds through the Operational Program ”Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) - Research Funding Program: THALIS.	en
heal.advisorName	Φράγκος, Παναγιώτης	el
heal.committeeMemberName	ΣΤΕΦΑΝΕΑΣ, ΠΕΤΡΟΣ	el
heal.committeeMemberName	ARKOUDAS, KONSTANTINE	en
heal.committeeMemberName	ΠΑΠΑΒΑΣΙΛΕΙΟΥ, ΣΥΜΕΩΝ	el
heal.committeeMemberName	ΚΟΛΕΤΣΟΣ, ΓΕΩΡΓΙΟΣ	el
heal.committeeMemberName	ΔΗΜΗΤΡΑΚΟΠΟΥΛΟΣ, ΚΩΝ/ΝΟΣ	el
heal.committeeMemberName	ΚΑΒΑΣΣΑΛΗΣ, ΠΕΤΡΟΣ	el
heal.academicPublisher	Σχολή Ηλεκτρολόγων Μηχανικών και Μηχανικών Υπολογιστών	el
heal.academicPublisherID	ntua
heal.numberOfPages	138
heal.fullTextAvailability	true