No description available.

Application Specific Integrated Circuits (ASICs) are critical to delivering on 5G’s promises of high speed, low latency, and expanded capacity. Digital Front-End (DFE) ASICs are particularly important components because they enhance crucial signal processing activities. It handles duties including carrier mixing, up-sampling, and modulation-demodulation, allowing for efficient data transmission and reception inthe complicated 5G environment. The main aim of this work is to develop a power estimation tool for DFE radio ASICs and to understand the different use cases. It also studies the spread of power consumption, taking into account process and metal variations. The thesis provides a detailed case study of the DFE ASIC, including its Intellectual Property (IP) blocks, configurations, and protocols. It investigates the power consumption of DFE ASICs under various conditions, including active processing, power-saving mode, and no clock. In this thesis we build a power model that describes how the factors affect the ASIC’s power consumption. It also performs spread analysis to evaluate the impact of all factors using MATLAB tool. Based on this we then generate three distributionmodels to study the combined likelihood of the variations. It also uses Monte Carlo simulation to understand total power usage. Through this work we can conclude that the power consumption of DFE ASICs is affected by a variety of factors. The power model and spread analysis can be usedto forecast and optimize power usage in 5G systems.

Acupuncture (AP) is an important constituent of the therapeutic repertoire of traditional Chinese medicine and has been widely used to alleviate chronic painful conditions all over the world. We studied in rats the efficiency of electroacupuncture (EAP) applied to the Zusanli acupoint (ST36) as an analgesic treatment over a 3-week period of time on purine (α,β-methylene ATP, dibenzoyl-ATP)- and acid (pH 6.0 medium)-induced pain in the rat paw. The two ATP derivatives stimulated P2X3 and P2X7 receptors, respectively, while the slightly acidic medium stimulated the “acid-sensitive ion channel 3” (ASIC3). It was found that the P2X7 receptor and ASIC-mediated pain was counteracted by EAP with greater efficiency at the end than at the beginning of the treatment schedule, while the P2X3 receptor–mediated pain was not. Our findings have important clinical and theoretical consequences, among others, because they are difficult to reconcile with the assumption that AP is primarily due to the release of peripheral and central opioid peptides causing the well-known tolerance to their effects. In consequence, AP is a convenient therapeutic instrument to treat subacute and chronic pain.

Video coding is widely used in our daily life. Due to its high computational complexity, hardware implementation is usually preferred. In this research, we investigate both ASIC hardware design approach and reconfigurable hardware design approach for video coding applications. First, we present a unified architecture that can perform Discrete Cosine Transform (DCT), Inverse Discrete Cosine Transform (IDCT), DCT domain motion estimation and compensation (DCT-ME/MC). Our proposed architecture is a Wavefront Array-based Processor with a highly modular structure consisting of 8*8 Processing Elements (PEs). By utilizing statistical properties and arithmetic operations, it can be used as a high performance hardware accelerator for video transcoding applications. We show how different core algorithms can be mapped onto the same hardware fabric and can be executed through the pre-defined PEs. In addition to the simplified design process of the proposed architecture and savings of the hardware resources, we also demonstrate that high throughput rate can be achieved for IDCT and DCT-MC by fully utilizing the sparseness property of DCT coefficient matrix. Compared to fixed hardware architecture using ASIC design approach, reconfigurable hardware design approach has higher flexibility, lower cost, and faster time-to-market. We propose a self-reconfigurable platform which can reconfigure the architecture of DCT computations during run-time using dynamic partial reconfiguration. The scalable architecture for DCT computations can compute different number of DCT coefficients in the zig-zag scan order to adapt to different requirements, such as power consumption, hardware resource, and performance. We propose a configuration manager which is implemented in the embedded processor in order to adaptively control the reconfiguration of scalable DCT architecture during run-time. In addition, we use LZSS algorithm for compression of the partial bitstreams and on-chip BlockRAM as a cache to reduce latency overhead for loading the partial bitstreams from the off-chip memory for run-time reconfiguration. A hardware module is designed for parallel reconfiguration of the partial bitstreams. The experimental results show that our approach can reduce the external memory accesses by 69% and can achieve 400 MBytes/s reconfiguration rate. Detailed trade-offs of power, throughput, and quality are investigated, and used as a criterion for self-reconfiguration. Prediction algorithm of zero quantized DCT (ZQDCT) to control the run-time reconfiguration of the proposed scalable architecture has been used, and 12 different modes of DCT computations including zonal coding, multi-block processing, and parallel-sequential stage modes are supported to reduce power consumptions, required hardware resources, and computation time with a small quality degradation. Detailed trade-offs of power, throughput, and quality are investigated, and used as a criterion for self-reconfiguration to meet the requirements set by the users.

No description available.

No description available.

The goal in medical x-ray imaging is to obtain the image quality requiredfor a given detection task, while ensuring that the patient dose is kept as lowas reasonably achievable. The two most common strategies for dose reductionare: optimizing incident x-ray beams and utilizing energy informationof transmitted beams with new detector techniques (spectral imaging). Inthis thesis, dose optimization schemes were investigated in two x-ray imagingsystems: digital mammography and computed tomography (CT). In digital mammography, the usefulness of anti-scatter grids was investigatedas a function of breast thickness with varying geometries and experimentalconditions. The general conclusion is that keeping the grid is optimalfor breasts thicker than 5 cm, whereas the dose can be reduced without a gridfor thinner breasts. A photon-counting silicon-strip detector developed for spectral mammographywas characterized using synchrotron radiation. Energy resolution, ΔE/Ein, was measured to vary between 0.11-0.23 in the energy range 15-40 keV, which is better than the energy resolution of 0.12-0.35 measured inthe state-of-the-art photon-counting mammography system. Pulse pileup hasshown little effect on energy resolution. In CT, the performance of a segmented silicon-strip detector developedfor spectral CT was evaluated and a theoretical comparison was made withthe state-of-the-art CT detector for some clinically relevant imaging tasks.The results indicate that the proposed photon-counting silicon CT detector issuperior to the state-of-the-art CT detector, especially for high-contrast andhigh-resolution imaging tasks. The beam quality was optimized for the proposed photon-counting spectralCT detector in two head imaging cases: non-enhanced imaging and Kedgeimaging. For non-enhanced imaging, a 120-kVp spectrum filtered by 2half value layer (HVL) copper (Z = 29) provides the best performance. Wheniodine is used in K-edge imaging, the optimal filter is 2 HVL iodine (Z = 53)and the optimal kVps are 60-75 kVp. In the case of gadolinium imaging, theradiation dose can be minimized at 120 kVp filtered by 2 HVL thulium (Z =69). / <p>QC 20160401</p>

Par le passé, la collaboration entre le Centre d'Imagerie Médicale de Sherbrooke (CIMS) et le Groupe de Recherche en Appareillage Médicale de Sherbrooke (GRAMS) a permis de développer le scanner LabPET. Celui-ci fut le premier scanner de Tomographie d'Émission par Positrons (TEP) commercial utilisant des photodiodes à effet avalanche (PDA) comme détecteur. Depuis, cette collaboration a permis de faire évoluer le scanner afin d'améliorer cette modalité d'imagerie et d'y ajouter la tomodensitométrie (TDM). Les attentes pour la prochaine génération du scanner sont donc grandes. Cette nouvelle génération du scanner, le LabPET II, verra les deux modalités nativement intégrées et elles utiliseront la même chaine de détection. Ce scanner se verra doté de nouveaux détecteurs organisés en matrices de 64 cristaux de 1,1 par 1,1 mm². Cette nouvelle matrice, associée à ses deux matrices de 32 PDA, a prouvé sa capacité à fournir une résolution spatiale inférieure au millimètre. L'utilisation de ce nouveau module de détection pourra donc permettre au LabPET II d'être le premier scanner bimodal (TEP/TDM) commercial atteignant une résolution submillimétrique. Ce scanner permettra de s'approcher un peu plus de la résolution spatiale ultime en TEP tout en permettant une bonne localisation anatomique grâce à l'ajout d'une imagerie TDM rudimentaire. Pour atteindre ces objectifs, une intégration complète de l'électronique frontale a été nécessaire. Dans les versions précédentes, seuls les préamplificateurs de charge et les filtres de mise en forme étaient intégrés; dans cette nouvelle version, toute l'électronique analogique ainsi que la numérisation et les liens de communications devront être intégrés. Pour ce faire, la technique de temps de survol au-dessus d'un seuil (ou ToT pour «Time-over-Threshold») a été préférée à la solution utilisée par le LabPET I qui nécessitait un convertisseur analogique-numérique par canal. La contrepartie de cette solution est l'obligation de maintenir la tension de base à une valeur fixe et commune à tous les canaux. Le circuit de polarisation des PDA a aussi dû être intégré dans l'ASIC, car il occupait énormément de place sur la carte d'électronique frontale du LabPET 1. Dans ce mémoire seront décrits la conception, l'intégration et les tests de ces deux circuits du système. Ils ont démontré leur efficacité tout en n'occupant que très peu de place dans le circuit intégré spécialisé (ASIC) du «module de détection». Au vu des sources bibliographiques recensées, le module de détection du LabPET II devrait être l'un de ceux ayant la plus forte densité de canaux (environ 45 par centimètre carré) et le seul combinant électronique analogique faible bruit, numérique et haute tension (~450 V). La réalisation de cette nouvelle génération devrait permettre au partenariat CIMS/GRAMS de réaffirmer leur position de leader dans le domaine en améliorant les outils d'imagerie à la disposition des chercheurs en médecine préclinique.

Cette thèse présente un système bioélectronique prometteur, l'Hynet. Ce Réseau Hybride (vivant-artificiel) est conçu pour l'étude du comportement à long terme des cellules électrogénératrices, comme les neurones et les cellules betas, en deux aspects : l'individuel et en réseau. Il est basé sur une boucle fermée et sur la communication en temps réel entre la culture cellulaire et une unité artificielle (Matériel, Logiciel). Le premier Hynet utilise des Matrices d'électrodes (MEA) commerciales qui limitent les performances spatiotemporelles du Hynet. Une nouvelle Matrice d'électrodes intelligente (iMEA) est développée. Ce nouveau circuit intégré, analogique et mixte, fournit une interface à forte densité, à forte échelle et adaptative avec la culture. Le nouveau système améliore le traitement des données en temps réel et une acquisition faible bruit du signal extracellulaire.

Clustered regularly interspaced short palindromic repeats (CRISPRs) act to prevent viral infection and horizontal gene transfer in prokaryotes. The genomic CRISPR array contains short sequences (“spacers”) that are derived from foreign genetic elements. The CRISPR array is transcribed and processed into CRISPR RNAs (crRNAs) used in the sequence-specific degradation of foreign nucleic acids. This process is called interference and is mediated by CRISPR-associated (Cas) proteins. This thesis has focused on the structural and functional characterisation of four Cas proteins from the CRISPR/Cas system of Sulfolobus solfataricus. The crystal structure of Cmr7 (Sso1725), a Sulfolobales-specific subunit of the ssRNA-degrading CMR complex, allowed for the identification of a putative protein-binding site, though no specific function could be ascribed to the protein. Cas6 (Sso1437) is the enzyme responsible for crRNA maturation and the characterisation of this protein allowed for the molecular rationalisation of its atypical RNA cleavage mechanism. Csa5 and Cas8a2 are subunits of the aCascade complex that targets dsDNA. Csa5 (Sso1398) was shown to have a putative role in R-loop stabilisation during interference while the role of Cas8a2 (Sso1401) was not determined. The structures of these two proteins were used to define relationships between the subunits of interference complexes from various CRISPR/Cas systems. A second aspect of this work has been the expression and purification of eukaryotic ion channels for structural studies. The acid sensing ion channel (ASIC) and FMRFamide-gated sodium channel (FaNaC) are gated ion channels with unknown mechanisms of channel activation. These ion channels must be expressed in eukaryotic systems and so human embryonic kidney (HEK) cells and baculovirus-insect cell expression systems were developed to express ASIC and FaNaC constructs. The expression and purification protocols have been optimised to allow for the preparation of soluble protein that will in future be used for crystallography and electron paramagnetic resonance (EPR) studies.