Comparative performance between human and automated face recognition systems, using CCTV imagery, different compression levels and scene parameters

In this investigation we identify relationships between human and automated face recognition systems with respect to compression. Further, we identify the most influential scene parameters on the performance of each recognition system. The work includes testing of the systems with compressed Closed-Circuit Television (CCTV) footage, consisting of quantified scene (footage) parameters. Parameters describe the content of scenes concerning camera to subject distance, facial angle, scene brightness, and spatio-temporal busyness. These parameters have been previously shown to affect the human visibility of useful facial information, but not much work has been carried out to assess the influence they have on automated recognition systems. In this investigation, the methodology previously employed in the human investigation is adopted, to assess performance of three different automated systems: Principal Component Analysis, Linear Discriminant Analysis, and Kernel Fisher Analysis. Results show that the automated systems are more tolerant to compression than humans. In automated systems, mixed brightness scenes were the most affected and low brightness scenes were the least affected by compression. In contrast for humans, low brightness scenes were the most affected and medium brightness scenes the least affected. Findings have the potential to broaden the methods used for testing imaging systems for security applications

Visual quality enhancement for color images in the framework of the JPEG2000 compression standard

In the last years, the consideration of different models of the Human Visual System (HVS) in the final perceived quality of the compressed images becomes a major research subject. Therefore, it is natural to take advantage of the recent knowledge on both perception and models of the human vision in an image compression system. Thus, in this paper we propose an integration method of that knowledge for the improvement of perceptual JPEG2000 image compression quality. This method consists on two parts : a laboratory evaluation of the HVS model by the Contrast Sensitivity Function (CSF), and an implementation technique of visual weightings for the JPEG2000 scheme, using the evaluated HVS model in the Fourier domain of the color image.Durant les dernières années, la prise en compte de modèles du Système Visuel Humain (SVH) dans l'évaluation de la qualité visuelle des images couleur compressées, est devenu un sujet de recherche majeur. Il semble naturel d'intégrer davantage les connaissances récentes sur la perception et la modélisation de la vision humaine, dans les systèmes de compression d'images. Ainsi, dans cet article, nous proposons une méthode d'intégration de ces connaissances pour l'augmentation de la qualité visuelle d'images compressées JPEG2000. Cette méthode consiste en deux parties : une évaluation de laboratoire pour la modélisation du SVH par la Fonction de Sensibilité au Contraste (CSF) et une technique de calcul de facteurs de pondération visuelle pour la compression JPEG2000, utilisant le modèle SVH évalué, dans le domaine de Fourier de l'image couleur

Hydrologic parameter sensitivity across a large-domain

Canada First Research Excellence FundNon-Peer ReviewedDue to the computational demands of modelling large domains, model calibration of Land Surface Models (LSMs) typically involves adjustment of only a small subset of parameters. • Majority of parameters that can potentially contribute to the model output variance remain fixed/ hard coded. • Spatial variability of the parameter sensitivity over large domains with heterogenous climatic and physiographic conditions is largely ignored during the calibration process. This work, carried out for parts of the Fraser and Columbia river basins, explored how parameter sensitivity varies spatially with the dominant physical and climatic conditions, and how dominant model parameters change depending on the simulated hydrologic process. The study found that parameter sensitivity varies both geographically and with the process being simulated

Active Air Injection Control to Enhance Performance of Hollow-bladed Axial Fan: A Numerical Study

Nowadays, axial fans participate in the most important areas of industry and research, including aviation, navy, wind tunnels, cooling towers, and even automobiles. Thus, more emphasis has been placed on improving their aerodynamic performances. It is important to notice that the parameters involved in designing a fan are mainly concerned with aeraulic power, torque and efficiency. This study investigates the utilization of flow control techniques to improve performances of an axial fan equipped with hollow blades, shroud, and hub. These features grant the fan crucial characteristics, namely, its lightweight and facilitate the blowing action by taking advantage on its hollow parts. The fan's performance is evaluated using a steady RANS numerical model with a k-ω SST turbulence closure, which was validated with experimental data. An active control air blowing through a slot was introduced with various positions and dimensions. The results demonstrate a significant improvement in the fan's performance, with an up to 56% increase in aeraulic power gain, accompanied by changes in the overall flow topology, noticed by closely analyzing the flow structure near the tip clearance

Innovative Overheating solution for solar thermal collector using a reflective surface included in the air gap

In this work, a new solution to prevent the overheating of solar collectors in the case of stagnation is presented. The solution proposed consists of inserting a reflective sheet inside the solar collector between the absorber and the glass cover to reduce the incoming energy by reflecting solar radiation. This protection is switched ON or OFF according to the absorber temperature. A prototype has been manufactured and tested in outside conditions and in laboratory. A numerical model of the solar collector with the protection was developed and has been validated. The calculated temperature values are very close to the measured data. The experimental and numerical results showed the good behaviour of the proposed solution

SYNERGETIC USE OF SENTINEL-1 AND SENTINEL-2 DATA FOR EXTRACTION OF BUILT-UP AREA IN A ROCKY DESERT OASIS, EXAMPLE FOR DRAA TAFILALT, SOUTH-EAST OF MOROCCO

Synthetic Aperture Radar (SAR) is an active remote sensing technique capable of providing high-resolution imagery independent from daytime and to great extent unimpaired by weather conditions. Unlike the passive remote sensing active radars receive its' own reflected signal. Features of received signal make able to obtain additional information about surface objects and covers. Because of signal, double reflecting upon vertical surfaces like walls, it become common to study urbanized areas using SAR data. Because of mostly similar spectral characteristic of the typical buildings' roofs and sandy soils, that are distinguishing for Morocco, classification using visible and NIR multispectral remote sensing data is complicated. Thus, SAR data processing technique is rather useful while application to deserted area studying and urbanized areas identification

The relationship between uremic toxins and symptoms in older men and women with advanced chronic kidney disease

Background: Patients with stage 4/5 chronic kidney disease (CKD) suffer from various symptoms. The retention of uremic solutes is thought to be associated with those symptoms. However, there are relatively few rigorous studies on the potential links between uremic toxins and symptoms in patients with CKD. Methods: The EQUAL study is an ongoing observational cohort study of non-dialyzed patients with stage 4/5 CKD. EQUAL patients from Germany, Poland, Sweden and the UK were included in the present study (n = 795). Data and symptom self-report questionnaires were collected between April 2012 and September 2020. Baseline uric acid and parathyroid hormone and 10 uremic toxins were quantified. We tested the association between uremic toxins and symptoms and adjusted P-values for multiple testing. Results: Symptoms were more frequent in women than in men with stage 4/5 CKD, while levels of various uremic toxins were higher in men. Only trimethylamine N-oxide (TMAO; positive association with fatigue), p-cresyl sulfate (PCS) with constipation and 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid (negative association with shortness of breath) demonstrated moderately strong associations with symptoms in adjusted analyses. The association of phenylacetylglutamine with shortness of breath was consistent in both sexes, although it only reached statistical significance in the full population. In contrast, TMAO (fatigue) and PCS and phenylacetylglutamine (constipation) were only associated with symptoms in men, who presented higher serum levels than women. Conclusion: Only a limited number of toxins were associated with symptoms in persons with stage 4/5 CKD. Other uremic toxins, uremia-related factors or psychosocial factors not yet explored might contribute to symptom burden.</p