Combining appearance and motion for face and gender recognition from videos

While many works consider moving faces only as collections of frames and apply still image-based methods, recent developments indicate that excellent results can be obtained using texture-based spatiotemporal representations for describing and analyzing faces in videos. Inspired by the psychophysical findings which state that facial movements can provide valuable information to face analysis, and also by our recent success in using LBP (local binary patterns) for combining appearance and motion for dynamic texture analysis, this paper investigates the combination of facial appearance (the shape of the face) and motion (the way a person is talking and moving his/her facial features) for face analysis in videos. We propose and study an approach for spatiotemporal face and gender recognition from videos using an extended set of volume LBP features and a boosting scheme. We experiment with several publicly available video face databases and consider different benchmark methods for comparison. Our extensive experimental analysis clearly assesses the promising performance of the LBP-based spatiotemporal representations for describing and analyzing faces in videos.     

Evaluation of the chemical composition and antimicrobial activity of Mentha pulegium,Juniperus phoenicea,and Cyperus longus essential oils from Morocco

The present study evaluates the chemical composition and antimicrobial activity of the essential oils (EOs) of Mentha pulegium L., Juniperus phoenicea L. and Cyperus longus L. from Morocco. The composition of these species was analyzed by GC/MS and 84 components were identified. M. pulegium EO showed a great similarity with EOs coming from other regions, as pulegone, the major component, accounted for about 70% of the EO. The EO of J. phoenicea had as main components α-pinene (24.9%), β-phellandrene (24.4%) and α-terpinyl acetate (12.9%). The EO extracted from C. longus was remarkably rich in sesquiterpene hydrocarbons (83.2%), which included β-himachalene (46.6%), α-humulene (16.9%), and γ-himachalene (10.1%). The antimicrobial activity of these EOs has been evaluated against seven bacteria of significant importance for food hygiene. According to the results, M. pulegium showed the best bacteriostatic and bactericidal effect, followed by J. phoenicea and C. longus. So far as we know, this is the first report on the quantitative composition and biological activity of the essential oil from C. longus. The tested EOs showed a variable degree of antimicrobial activity being M. pulegium the most effective one.     

Design of dedicated seven-port star dividers for sectored circular antenna array feeding

In order to mitigate the multipath propagation problems for high rate wlans such as Hiperlan (5 GHz) [2], we study an approach based on electronic beam steering over 360° in azimuth with the help of circular arrays of monopoles [3]. Design simplicity and size constraints intended for potential low-cost applications on the terminals has led us to favor a beam switching topology, using a single feeding-port [4]. Two competing configurations of the microstrip feeding circuit are presented and their principle of operation is experimentally validated through passive circuit configurations. The power distribution is achieved in the first one with the help of a pseudo-divider based on a modified 7-branch star junction, whose specific advantage is its very small size. Unfortunately, this design does not preserve the circular permutation invariance of the radiation patterns. The second circuit bypasses this problem in achieving a power distribution through a virtual point junction, at the cost of an appreciable increase in the circuit size.     

Smooth head tracking for virtual reality applications

In this work, we propose a new head-tracking solution for human–machine real-time interaction with virtual 3D environments. This solution leverages RGBD data to compute virtual camera pose according to the movements of the user’s head. The process starts with the extraction of a set of facial features from the images delivered by the sensor. Such features are matched against their respective counterparts in a reference image for the computation of the current head pose. Afterwards, a prediction approach is used to guess the most likely next head move (final pose). Pythagorean Hodograph interpolation is then adapted to determine the path and local frames taken between the two poses. The result is a smooth head trajectory that serves as an input to set the camera in virtual scenes according to the user’s gaze. The resulting motion model has the advantage of being: continuous in time, it adapts to any frame rate of rendering; it is ergonomic, as it frees the user from wearing tracking markers; it is smooth and free from rendering jerks; and it is also torsion and curvature minimising as it produces a path with minimum bending energy.     

Role of general stress-response alternative sigma factors σ(S) (RpoS) and σ(B) (SigB) in bacterial heat resistance as a function of treatment medium pH

This investigation aimed to determine the role of general stress-response alternative sigma factors σ^S (RpoS) and σ^B (SigB) in heat resistance and the occurrence of sublethal injuries in cell envelopes of stationary-phase Escherichia coli BJ4 and Listeria monocytogenes EGD-e cells, respectively, as a function of treatment medium pH. Given that microbial death followed first-order inactivation kinetics (R² > 0.95) the traditional D_T and z values were used to describe the heat inactivation kinetics.Influence of rpoS deletion was constant at every treatment temperature and pH, making a ΔrpoS deletion mutant strain approximately 5.5 times more heat sensitive than its parental strain for every studied condition. Furthermore, the influence of the pH of the treatment medium on the reduction of the heat resistance of E. coli was also constant and independent of the treatment temperature (average z value = 4.9 °C) in both parental and mutant strains.L. monocytogenes EGD-e z values obtained at pH 7.0 and 5.5 were not significantly different (p > 0.05) in either parental or the ?sigB deletion mutant strains (average z value = 4.8 °C). Nevertheless, at pH 4.0 the z value was higher (z = 8.4 °C), indicating that heat resistance of both L. monocytogenes strains was less dependent on temperature at pH 4.0. At both pH 5.5 and 7.0 the influence of sigB deletion was constant and independent of the treatment temperature, decreasing L. monocytogenes heat resistance approximately 2.5 times. In contrast, the absence of sigB did not decrease the heat resistance of L. monocytogenes at pH 4.0.The role of RpoS in protecting cell envelopes was more important in E. coli (4 times) than SigB in L. monocytogenes (1.5 times). Moreover, the role of σ^S in increasing heat resistance seems more relevant in enhancing the intrinsic resilience of the cytoplasmic membrane, and to a lesser extent, outer membrane resilience.Knowledge of environmental conditions related to the activation of alternative sigma factors σ^S and σ^B and their effects on heat resistance would help us to avoid and/or identify situations that increase bacterial stress resistance. Therefore, more efficient food preservation processes might be designed.     

Audiovisual synchrony assessment for replay attack detection in talking face biometrics

Audiovisual speech synchrony detection is an important liveness check for talking face verification systems in order to make sure that the input biometric samples are actually acquired from the same source. In prior work, the used visual speech features have been mainly describing facial appearance or mouth shape in frame-wise manner, thus ignoring the lip motion between consecutive frames. Since also the visual speech dynamics are important, we take the spatiotemporal information into account and propose the use of space-time auto-correlation of gradients (STACOG) for measuring the audiovisual synchrony. For evaluating the effectiveness of the proposed approach, a set of challenging and realistic attack scenarios are designed by augmenting publicly available BANCA and XM2VTS datasets with synthetic replay attacks. Our experimental analysis shows that the STACOG features outperform the state of the art, e.g. discrete cosine transform based features, in measuring the audiovisual synchrony.     

Mechanical investigation of two fiber-reinforced repair mortars and the repaired system

The mechanical behavior of two repair mortars was investigated. The first one is a fiber reinforced lime-based mortar, which contains thickening agent and limestone additions. The second one is a fiber reinforced ordinary mortar, which contains a small quantity of silica fume and additives. Mechanical characterization was based on compression, tensile and three-point bending tests. The bond between the repair mortars and substrate was investigated by slant shear and flexural bonding tests. The results obtained have demonstrated the influence of the surface roughness and moisture conditions on the bond strength. Finally, Scanning Electron Microscopic observations have showed the morphology of the repair mortar-to-substrate interfacial zone.     

POSSIBILISTIC ACTIVITY RECOGNITION IN SMART HOMES FOR COGNITIVELY IMPAIRED PEOPLE

In order to maintain and improve the quality of life in the homes of people with dementia, we must elaborate assistive technologies that will alleviate the effects of cognitive decline, such as those erroneous behaviors associated with carrying on activities of daily living (ADL). In order to provide adequate assistive services at the opportune moment, it is necessary to recognize the occupant behavior from sensor events of the smart home. To address this challenge, this paper presents a formal model of activity recognition in smart homes based on possibility theory and environmental contexts. This activity recognition model is able to take into account coherent and erroneous behaviors that may result from the cognitive decline of the occupant. An implementation of this model was validated in a smart home laboratory with valid sensor data from coherent and erroneous realizations of an ADL scenario.