On monday, at 2pm - UPEC CMC - Room P2-131

June 12, 2017

TBA

Yuri Gurevich (Microsoft Research)

May 22, 2017

On the chemistry of typestate-oriented actors

Silvia Crafa (Université de Padoue)

Typestate-oriented programming is an extension of the OO paradigm in which objects are modeled not just in terms of interfaces but also in terms of their usage protocols, describing legal sequences of method calls, possibly depending on the object’s internal state. We argue that the Actor Model allows typestate-OOP in an inherently distributed setting, whereby objects/actors can be accessed concurrently by several processes, and local entities cooperate to carry out a communication protocol. We illustrate the approach by means of a number of examples written in Scala Akka.

May 15, 2017

TBA

Thomas Fernique (LIPN)

TBA

April 24, 2017

Computational modeling using P systems

Agustín Riscos Núñez (Universidad de Sevilla)

The talk will try to provide a general overview of modeling frameworks for systems biology and population dynamics based on membrane computing.
We will overview some recent achievements which show that this unconventional and bio-inspired computing paradigm can be an alternative to classical modeling frameworks (e.g. those based on differential equations).
We will also refer to the associated simulation software tools which are necessary to enable virtual experimentation, as well as for the process of model validation.

April 3, 2017

Non-commutative lower bounds

Guillaume Lagarde (IRIF)

No knowledge in arithmetic complexity will be assumed.
We still don’t know an explicit polynomial that requires non-commutative circuits of size at least superpolynomial.
However, the context of non commutativity seems to be convenient to get such lower bound because the rigidity of the non-commutativity implies a lot of constraints about the ways to compute.
It is in this context that Nisan, in 1991, provides an exponential lower bound against the non commutative Algebraic Branching Programs computing the permanent, the very first one in arithmetic complexity. We show that this result can be naturally seen as a particular case of a theorem about circuits with *unique parse tree*, and show some extensions to get closer to lower bounds for general NC circuits.
Two joint works: with Guillaume Malod and Sylvain Perifel; with Nutan Limaye and Srikanth Srinivasan.

March 27, 2017

TBA

Catalin Dima (LACL)

TBA

March 20, 2017

Parameterised Verification of Epistemic Properties in Security Protocols

Ioana boureanu (University of Surrey)

Abstract: Verifying certain security requirements is not even always decidable. Furthermore, properties like privacy preservation, which are not expressible as trace properties, can be verified only via few methodologies. In this talk, we will see some of these challenges and how they can be tackled, in part, by parameterised verification of temporal-epistemic logics in specialised multi-agent system semantics.

March 20, 2017

Parameterised Verification of Epistemic Properties in Security Protocols

Ioana boureanu (University of Surrey)

Abstract: Verifying certain security requirements is not even always decidable. Furthermore, properties like privacy preservation, which are not expressible as trace properties, can be verified only via few methodologies. In this talk, we will see some of these challenges and how they can be tackled, in part, by parameterised verification of temporal-epistemic logics in specialised multi-agent system semantics.

February 27, 2017

Probabilistic Disclosure: Maximisation vs. Minimisation

Serge Haddad (LSV)

We consider opacity questions where an observation function provides
to an external attacker a view of the states along executions and
secret executions are those visiting some secret state from a fixed
subset. Disclosure occurs when the observer can deduce from a finite
observation that the execution is secret. In a probabilistic and non
deterministic setting, where an internal agent can choose between
actions, there are two points of view, depending on the status of
this agent: the successive choices can either help the attacker
trying to disclose the secret, if the system has been corrupted, or
they can prevent disclosure as much as possible if these choices are
part of the system design. In the former situation, corresponding to
a worst case, the disclosure value is the supremum over the
strategies of the probability to disclose the secret (maximisation),
whereas in the latter case, the disclosure is the infimum
(minimisation). We address quantitative problems (relation between
the optimal value and a threshold) and qualitative ones (when the
threshold is zero or one) related to both forms of disclosure for a
fixed or finite horizon. For all problems, we characterise their
decidability status and their complexity. Surprisingly, while in
maximisation problems optimal strategies may be chosen among
deterministic ones, it is not the case for minimisation problems,
but more minimisation problems than maximisation ones are decidable.