# LSV Seminar

The LSV seminar takes place on Tuesday at 11:00 AM. The usual location is the conference room at Pavillon des Jardins (venue).
If you wish to be informed by e-mail about upcoming seminars, please contact Stéphane Le Roux and Matthias Fuegger.

The seminar is open to public and does not require any form of registration.

## Past Seminars

### Opacity for Linear Constraint Markov Chains

- Date
- Tuesday, November 08 2016 at 11:00AM
- Place
- Salle de Conférence (Pavillon des Jardins)
- Speaker
- Béatrice Bérard (LIP6, U. Pierre & Marie Curie)

On a partially observed system, a secret φ is opaque if an observer
cannot ascertain that its trace belongs to φ. We consider specifications
given as Constraint Markov Chains (CMC), which are underspecified
Markov chains where probabilities on edges are required to belong to some set.
The nondeterminism is resolved by a scheduler, and opacity on this model
is defined by disclosure, a worst case measure over all implementations obtained
by scheduling. Hence disclosure measures the information obtained by a passive
observer when the system is controlled by the smartest scheduler in coalition with
the observer. When restricting to the subclass of Linear CMC, we compute (or
approximate) this measure and prove that refinement of a specification can only
improve opacity.

Joint work with Olga Kouchnarenko, John Mullins and Mathieu Sassolas,
extended version from WODES 2016.