Recognition of 3D facial expression dynamics

In this paper we propose a method that exploits 3D motion-based features between frames of 3D facial geometry sequences for dynamic facial expression recognition. An expressive sequence is modelled to contain an onset followed by an apex and an offset. Feature selection methods are applied in order to extract features for each of the onset and offset segments of the expression. These features are then used to train GentleBoost classifiers and build a Hidden Markov Model in order to model the full temporal dynamics of the expression. The proposed fully automatic system was employed on the BU-4DFE database for distinguishing between the six universal expressions: Happy, Sad, Angry, Disgust, Surprise and Fear. Comparisons with a similar 2D system based on the motion extracted from facial intensity images was also performed. The attained results suggest that the use of the 3D information does indeed improve the recognition accuracy when compared to the 2D data in a fully automatic manner.     

Thermal Aging Behavior of Pt-only TWC Converters Under Simulated Exhaust Conditions: Effect of Rare Earths (CeO2, La2O3) and Alkali (Na) Modifiers

In the present work, the feasibility to design monometallic (Pt-only), low metal loading (0.1 wt% Pt) three-way catalytic converters (TWCs), with comparable catalytic efficiency and thermostability to that of commercial bimetallic Pt/Rh TWCs has been explored. It is shown that this can be accomplished by modifying Pt/??-??l₂O₃ washcoat of TWC via two different methods of promotion: support-mediated promotion by modifying the ??-Al₂O₃ support with rare earth structure-modifiers (CeO₂?CLa₂O₃) and surface-induced promotion by directly modifying the Pt surface with alkalies (e.g., Na), producing a doubly-promoted Pt(Na)/Al₂O₃-(CeO₂?CLa₂O₃) TWC. The catalytic performance of as prepared TWCs in comparison to that of a commercial bimetallic (Pt?CRh) TWC, under simulated exhaust conditions at the stoichiometric point appears to be superior, even after severe thermal treatment at 900 °C for 5 h in air and despite the fact that the latter contain 4.5-fold higher noble metals loading. Moreover, the evolution of structural, textural and surface behavior of aged catalysts was identified by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy and diffuse reflectance infrared Fourier transform spectroscopy and appropriately correlated with the catalytic performance and thermostability of TWCs.