Self-sustained coherent phonon generation in optomechanical cavities

Optical forces can set tiny objects in states of mechanical self-sustained oscillation, spontaneously generating periodic signals by extracting power from steady sources. Miniaturized self-sustained coherent phonon sources are interesting for applications such as mass-force sensing, intra-chip metrology and intra-chip time-keeping among others. In this paper, we review several mechanisms and techniques that can drive a mechanical mode into the lasing regime by exploiting the radiation pressure force in optomechanical cavities, namely stimulated emission, dynamical back-action, forward stimulated Brillouin scattering and self-pulsing.

Robustness with Respect to Delay Uncertainties of a Predictor-Observer Based Discrete-Time Controller

This paper focuses on the delay-dependent stability problem of a discrete-time prediction scheme to stabilize possible unstable continuous-time systems. The delay-dependent stability condition is expressed in terms of LMIs. The separation principle between the proposed predictor and a state observer is also proved. The closed-loop system is shown to be robust with respect to uncertainties in the knowledge on the plant parameters, the delay and the sampling period. The proposed scheme has been tested in a real-time application to control the roll angle in a prototype of a quad-rotor mini-helicopter.

The challenge of habitat modelling for threatened low density species using heterogeneous data: The case of Cuvier’s beaked whales in the Mediterranean

We are grateful to the ACCOBAMS Secretariat for their support in this work, including a small grant for the analysis. The Mediterranean population of Cuvieŕs beaked whale (Ziphius cavirostris), a deep-diving cetacean, is genetically distinct from the Atlantic, and subject to a number of conservation threats, in particular underwater noise. It is also cryptic at the surface and relatively rare, so obtain robust knowledge on distribution and abundance presents unique challenges. Here we use multiplatform and multiyear survey data to analyse the distribution and abundance of this species across the Mediterranean Sea. We use a novel approach combining heterogeneous data gathered with different …

Determinationes magistrales contra conclusiones Johannis Pici Mirandulani

Estimating feature discriminant power in decision tree classifiers

Feature Selection is an important phase in pattern recognition system design. Even though there are well established algorithms that are generally applicable, the requirement of using certain type of criteria for some practical problems makes most of the resulting methods highly inefficient. In this work, a method is proposed to rank a given set of features in the particular case of Decision Tree classifiers, using the same information generated while constructing the tree. The preliminary results obtained with both synthetic and real data confirm that the performance is comparable to that of sequential methods with much less computation.