References of "Aucher, Guillaume 40000019"
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See detailA dynamic logic for privacy compliance
Aucher, Guillaume UL; Boella, Guido; van der Torre, Leon UL

in Artificial Intelligence & Law (2011)

Knowledge based privacy policies are more declarative than traditional action based ones, because they specify only what is permitted or forbidden to know, and leave the derivation of the permitted ... [more ▼]

Knowledge based privacy policies are more declarative than traditional action based ones, because they specify only what is permitted or forbidden to know, and leave the derivation of the permitted actions to a security monitor. This inference problem is already non trivial with a static privacy policy, and becomes challenging when privacy policies can change over time. We therefore introduce a dynamic modal logic that permits not only to reason about permitted and forbidden knowledge to derive the permitted actions, but also to represent explicitly the declarative privacy policies together with their dynamics. The logic can be used to check both regulatory and behavioral compliance, respectively by checking that the permissions and obligations set up by the security monitor of an organization are not in conflict with the privacy policies, and by checking that these obligations are indeed enforced. [less ▲]

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See detailDynamics in Delegation and Revocation Schemes: A Logical Approach
Aucher, Guillaume UL; Barker, Steve; Boella, Guido UL et al

in DBSec (2011)

In this paper we first introduce a logic for describing formally a family of delegation and revocation models that are based on the work in Hagström et al.. We then extend our logic to accommodate an ... [more ▼]

In this paper we first introduce a logic for describing formally a family of delegation and revocation models that are based on the work in Hagström et al.. We then extend our logic to accommodate an epistemic interpretation of trust within the framework that we define. What emerges from this work is a rich framework of formally well-defined delegation and revocation schemes that accommodates an important trust component. [less ▲]

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See detailAn internal version of epistemic logic
Aucher, Guillaume UL

in Studia Logica (2010), 94(1), 1-22

Representing an epistemic situation involving several agents obviously depends on the modeling point of view one takes. We start by identifying the types of modeling points of view which are logically ... [more ▼]

Representing an epistemic situation involving several agents obviously depends on the modeling point of view one takes. We start by identifying the types of modeling points of view which are logically possible. We call the one traditionally followed by epistemic logic the perfect external approach, because there the modeler is assumed to be an omniscient and external observer of the epistemic situation. In the rest of the paper we focus on what we call the internal approach, where the modeler is one of the agents involved in the situation. For this approach we propose and axiomatize a logical formalism based on epistemic logic. This leads us to formalize some intuitions about the internal approach and about its connections with the external ones. Finally, we show that our internal logic is decidable and PSPACE-complete. [less ▲]

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See detailPrivacy Policies with Modal Logic: The Dynamic Turn
Aucher, Guillaume UL; Boella, Guido; van der Torre, Leon UL

in DEON (2010)

Privacy policies are often defined in terms of permitted messages. Instead, in this paper we derive dynamically the permitted messages from static privacy policies defined in terms of permitted and ... [more ▼]

Privacy policies are often defined in terms of permitted messages. Instead, in this paper we derive dynamically the permitted messages from static privacy policies defined in terms of permitted and obligatory knowledge. With this new approach, we do not have to specify the permissions and prohibitions of all message combinations explicitly. To specify and reason about such privacy policies, we extend a multi-modal logic introduced by Cuppens and Demolombe with update operators modeling the dynamics of both knowledge and privacy policies. We show also how to determine the obligatory messages, how to express epistemic norms, and how to check whether a situation is compliant with respect to a privacy policy.We axiomatize and prove the decidability of our logic. [less ▲]

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See detailDynamic context logic and its application to norm change
Aucher, Guillaume UL; Grossi, Davide; Herzig, Andreas et al

in Proceedings of Dagstuhl Seminar (2009, November 03), 09121

Building on a simple modal logic of context, the paper presents a dynamic logic characterizing operations of contraction and expansion on theories. We investigate the mathematical properties of the logic ... [more ▼]

Building on a simple modal logic of context, the paper presents a dynamic logic characterizing operations of contraction and expansion on theories. We investigate the mathematical properties of the logic, and use it to develop an axiomatic and semantic analysis of norm change in normative systems. The proposed analysis advances the state of the art by providing a formal semantics of norm-change which, at the same time, takes into account several different aspects of the phenomenon, such as permission and obligation dynamics, as well as the dynamics of classificatory rules. [less ▲]

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See detailDynamic context logic
Aucher, Guillaume UL; Grossi, Davide; Herzig, Andreas et al

in Logic, Rationality, and Interaction (2009)

Building on a simple modal logic of context, the paper presents a dynamic logic characterizing operations of contraction and expansion on theories. We investigate the mathematical properties of the logic ... [more ▼]

Building on a simple modal logic of context, the paper presents a dynamic logic characterizing operations of contraction and expansion on theories. We investigate the mathematical properties of the logic, and show how it can capture some aspects of the dynamics of normative systems once they are viewed as logical theories. [less ▲]

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See detailBMS revisited
Aucher, Guillaume UL

in Proceedings of the 12th Conference on Theoretical Aspects of Rationality and Knowledge (2009)

The insight of the BMS logical framework (proposed by Baltag, Moss and Solecki) is to represent how an event is perceived by several agents very similarly to the way one represents how a static situation ... [more ▼]

The insight of the BMS logical framework (proposed by Baltag, Moss and Solecki) is to represent how an event is perceived by several agents very similarly to the way one represents how a static situation is perceived by them: by means of a Kripke model. There are however some differences between the definitions of an epistemic model (representing the static situation) and an event model. In this paper we restore the symmetry. The resulting logical framework allows, unlike any other one, to express statements about ongoing events and to model the fact that our perception of events (and not only of the static situation) can also be updated due to other events. We axiomatize it and prove its decidability. Finally, we show that it embeds the BMS one if we add common belief operators. [less ▲]

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See detailExploring the power of converse events
Aucher, Guillaume UL; Herzig, Andreas

in Dynamic Formal Epistemology (2009)

Dynamic epistemic logic as viewed by Baltag, Moss and Solecki (BMS) and propositional dynamic logic (PDL) offer different semantics of events. On the one hand, BMS adds dynamics to epistemic logic by ... [more ▼]

Dynamic epistemic logic as viewed by Baltag, Moss and Solecki (BMS) and propositional dynamic logic (PDL) offer different semantics of events. On the one hand, BMS adds dynamics to epistemic logic by introducing so-called event models as syntactic objects into the language. On the other hand, PDL has instead transition relations between possible worlds. This last approach allows to easily introduce converse events. In this paper we add epistemics to this, and call the resulting logic epistemic dynamic logic (EDL). We show that BMS can be translated into EDL thanks to this use of the converse operator : it enables us to translate the structure of the event model directly within a particular axiomatization of EDL, without having to refer to a particular epistemic event model in the language (as done in BMS).We show that EDL is more expressive and general than BMS and we characterize semantically and syntactically in EDL this embedding of BMS. [less ▲]

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