Co-conception et caractérisation de circuits actifs et passifs tri-dimensionnels en bande K pour l'intégration de mycrosystèmes sur silicium aux fréquences milimétriques

The work presented in this thesis addresses the potentialities of new technologies available to responds to firstly the needs of increased operating frequencies and secondly to the miniaturization of the communication systems with enhanced RF performances. This study is based on the design of an image rejected mixer which allows slackening the constraints on the image filter in the front of the system. The integration of the two parts active and passive of the system, has been carried out with the aim to get the maximum of the potentialities of each technology, to offer technical solutions to overcome the disadvantages of each technology, to optimise the global architecture by dividing the system according to the constraints of the technology and/or the technical constraints. The first part of this study deal with the development of a new mixer structure in the K band with enhanced linearity and based on heterojunction transistors. Based on an understanding of intrinsic phenomena of the circuit, modified topologies have been proposed as well to improve the whole performances achievable in such technology. The second part of this study investigates on the design of passive couplers, in K band too, with the aim of miniaturizing these functions to the maximum. A design method has been developed and validated thanks to the integration in a specific technology developed at the LAAS-CNRS and compatible with future integration with the active circuits. Therefore, optimal performances (state of the art) have been obtained with an integration level improved by 2. Finally, at the beginning and end of this work, a study on the global architecture of the image rejected mixer system has been investigate, and continuously refined, to divide the performance constraints between the different blocks and to verify the obtaining performances.Les travaux menés dans le cadre de cette thèse proposent de tirer profit des nouvelles technologies disponibles pour répondre aux besoins de la montée en fréquence et de la miniaturisation des systèmes de communication tout en améliorant le niveau des performances. Les études se sont axées vers la conception d'une structure à mélangeur de réjection de fréquence image permettant de relâcher les contraintes sur les structures critiques de filtrage amont. L'intégration des parties actives et passives de ce système, a ainsi été menée avec comme objectifs de tirer au maximum partie des potentialités de chaque technologie, de proposer des solutions techniques pour palier aux inconvénients de chaque technologie, et d'optimiser l'architecture globale en partitionnant le système suivant les contraintes technologiques et/ou techniques. La première partie des travaux a ainsi porté sur le développement en bande K d'une nouvelle topologie de mélangeur à base de transistors à hétérojonction Si-SiGe à linéarité améliorée. Se basant sur une compréhension des phénomènes intrinsèques du circuit, des topologies modifiées ont de plus été proposés afin de repousser l'ensemble des performances atteignables sur cette technologie. La seconde partie des travaux concerne la conception de coupleurs passifs, toujours en bande K, avec pour objectif la miniaturisation maximale de ces fonctions. Une méthodologie de conception a, dans ce cadre, été développée et validée par une intégration sur une technologie spécifiquement développée au LAAS-CNRS et compatible avec une future intégration avec les circuits actifs. Nous avons ainsi obtenu des performances optimales (à l'état de l'art) avec un gain d'intégration d'un facteur 2. Enfin, en amont et en aval de ces travaux, une étude sur l'architecture globale du système de mélangeur à réjection de fréquence image a été conduite, et sans cesse raffinée, afin de partitionner les contraintes de performances entre les différents blocs et de vérifier l'obte ntion des performances

Co-conception et caractérisation de circuits actifs et passifs tri-dimensionnels en bande K pour l'intégration de mycrosystèmes sur silicium aux fréquences milimétriques

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

REAL-TIME FACE DETECTION AND HUMAN TRACKING SYSTEM ON FPGA CYCLONE-V

Face detection in image sequence (real-time video stream) has been an active research area in the computer vision field in recent years due to its potential applications such as surveillance cameras, human computer interfaces, smart rooms, intelligent robots and biomedical image analysis. Face detection is a process that determines whether an image has a face or not. In this paper, an embedded system for detecting and tracking human faces in real-time video stream implemented on FPGA DE10-NANO is proposed. The system can be divided into two parts: data streaming, data processing. Experimental results show that the system is capable of accurately detecting faces of up to 5 different people at a distance of up to 1.5 meters from the camera, coexisting in the same frame in resolution of 320x240 pixels with a detection speed of only several hundred milliseconds prove the feasibility of the system. A comparison with similar existing projects will be discussed for evaluation and conclusion as well

Design Of Deep Learning Model Applied For Smart Parking System

This article proposes and introduces a smart parking system using RFID technology incorporating a Deep Learning model to identify license plates. It tries to simulate the ability of the brain to recognize, differ- entiate and learn patterns from data. The employed algorithms are mainly based on neural network mod- els where neurons are organized in stacked layers. The system is designed to manage incoming and outgoing vehicles by collecting and processing images and data on passenger information to update parking status with the news of empty lots. Another function of the park- ing system also designed is a fully automatic method of paying the parking fee by the user. The deep learning model for the smart parking system is implemented us- ing the Raspberry PI 3 embedded system and sensors. Experimental results with the plate identification rate in the worst condition, up to 80%, have proven the re- liability of the proposed smart parking system. In terms of quantity, the percentage of the worst plate identifi- cation down to 10% has established the stability of the proposed smart parking system

Aerospace competition, investor attention, and stock return comovement

Fierce aerospace competition among global superpowers has resulted in strong public attention on satellite launch events in the U.S. Given limited attentional resources, U.S. investors pay more attention to market-level shocks than to firm-specific shocks, making stock returns comove more with the market on satellite launch days than on other days. We find that the effect is significantly stronger for military-related satellite launches, launches before the dissolution of the former Soviet Union, and international satellite launches by other competitors, highlighting a greater concern for national security. A trading strategy that exploits the potential satellite-induced mispricing yields an annualized abnormal risk-adjusted return of up to 17% within the three-day window around launch date. Our results are robust to a battery of robustness analyses that consider the different characteristics of satellite launches, the exclusion of aerospace firms, and stock return comovement with industries.</p

Political similarities in credit ratings

We investigate whether political similarities between credit rating agencies (CRAs) and bond issuers impact credit rating quality. We find that a higher degree of similarity of political affiliation leads to a decrease in timeliness and accuracy of downgrades prior to default events. Our finding supports the notion that CRAs tend to maintain/assign preferential ratings to politically similar firms via delaying negative signals as favourable rating activities. We further show that these politically similar firms tend to increase the proportion of donations to their favoured party following favourable credit ratings. Interestingly, this result is confined to Republican-leaning firms. The results indicate that CRAs successfully use biased credit ratings as an indirect channel of political party support. Our findings support the political similarities in credit ratings hypothesis

Determination of Caffeine, Chlorogenic Acid, Total Phenolic Contents, and Antioxidant Capacities for Arabica and Robusta Coffee from Vietnam

In Vietnam, the cultivation and production of coffee have been expanding over the past few decades and are known as an important part of the national economy. However, the scientific data regarding the internal compositions of coffee have still been limited, especially the changes during the processing, typically the roasting period. The present study aimed to demonstrate an insight into the variations in chlorogenic acid, caffeine, total phenolic contents (TPCs), and trolox equivalent antioxidant capacities for two common coffee species, that is, Robusta and Arabica, and three roasting levels, that is, light, medium, and dark. Generally, Robusta coffee performed higher chlorogenic acid, caffeine, and TPCs, resulting in dominant antioxidant capacities compared to Arabica. High Pearson correlation coefficients (calculated by SPSS) were found for most pairs of parameters, r > 0.80. Regarding roasting levels, a descending order was highlighted for most analytical parameters: light > medium > dark. Two parallel processes in the roasting period were revealed by observing the antioxidant capacities, that is, thermal degradation and formation of other antioxidants by the Maillard reaction. Principal component analysis (SIMCA-P 11) was attempted to discriminate the available coffee samples by their species and roasting levels, indicating proper classification (the cumulative variance is 95.3%).</p