Cultural emergence of combinatorial structure in an artificial whistled language

Speech sounds within a linguistic system are both categorical and combinatorial and there are constraints on how elements can be recombined. To investigate the origins of this combinatorial structure, we conducted an iterated learning experiment with human participants, studying the transmission of an artificial system of sounds. In this study, participants learn and recall a system of sounds that are produced with a slide whistle, an instrument that is both intuitive and non-linguistic. The system they are exposed to is the recall output of the previous participant. Transmission from participant to participant causes the system to change and become cumulatively more learnable and more structured. This shows that combinatorial structure can culturally emerge in an artificial sound system through iterated learning

Deformable templates for tracking and analysis of intravascular ultrasound sequences

Deformable Template models are first applied to track the inner wall of coronary arteries in intravascular ultrasound sequences, mainly in the assistance to angioplasty surgery. A circular template is used for initializing an elliptical deformable model to track wall deformation when inflating a balloon placed at the tip of the catheter. We define a new energy function for driving the behavior of the template and we test its robustness both in real and synthetic images. Finally we introduce a framework for learning and recognizing spatio-temporal geometric constraints based on Principal Component Analysis (eigenconstraints)