Environnement de conception multi-niveaux unifiée appliqué aux systèmes mixtes

Nowadays, System-on-Chips containing digital, analog and RF blocks are very common and are present in almost all electronic devices. This fact brings the designers of analog and digital domains to work together to apply a complete analog/digital Mixed-Signal design. A system-level model containing both the analog and digital parts is very important to determine the circuit specifications and to validate the desired system performance. Tools available to model such systems are currently lacking: Matlab, a widely used high-level simulator is not compatible with the integrated circuit design flow. VHDL-AMS, a language for analog mixed-signal circuit description is very time-consuming for large systems. Recently, an AMS extension of SystemC, called SystemC AMS, has filled this gap of Mixed Signal modeling in a system level. At the circuit level, the conventional analog design methodologies have been mainly based on the analog designer approximated calculations and computer-aided simulations for tuning. The design time of analog and RF blocks is very dependent on the designer's experience. When the CMOS process or the specifications are changed a complete redesign is necessary. Moreover, it is very difficult to optimize the overall design of a complex mixed-signal circuit because the design and simulation environments used for the digital blocks are very different from those used for the analog and RF blocks. The following points summarize the contributions realized in this work. - The first implementation of a fairly complex Mixed Signal model in SystemC-AMS: a Wireless Sensor Network node. - Refined models for a generic and configurable approach of system-level modeling. - An accurate linear and nonlinear circuit performance evaluation tool for system-level refined models back-annotation and circuit-level optimized design. - An optimized circuit design methodology based on an accurate sizing tool and the circuit performance evaluation tool. - A unified Mixed Signal design environment with a very strong interaction between system-level simulation and optimized circuit-level design.Ce travail se place dans le contexte de la conception, la modélisation et la simulation de systèmes hétérogènes contenant a la fois des capteurs, des composants analogiques, des composants numériques et des circuits RF.La seule manière de simuler un système avec une telle complexité avec un temps de simulation raisonnable est de faire une modélisation haut niveau.Cependant, pour que ce modèle haut niveau soit fiable, les modèles des blocs analogiques et RF doivent contenir une description précise des leurs imperfections.Dans ce travail nous proposons une méthode systématique pour la caractérisation et le raffinement des modèles des blocs analogiques et RF.Cette méthode est réalisée dans un environnement C++ base sur: - l'outil de simulation haut niveau SystemC-AMS- l'outil de résolution d'expression symbolique GiNaC- l'outil de synthèse de circuits intégrés analogique CAIRO+/CHAMSPour illustrer la validité de la méthode proposée, nous présenterons le modèle d'un nœud d'un réseau de capteurs sans fil avec une caractérisation automatique de certains blocs analogiques et RF.Les points suivant résument les contributions apportées pour ce travail.- La première implémentation d'un modèle analogique numérique mixte complexe avec le langage SystemC AMS: un nœud de réseau de capteurs sans fil.- L'introduction du raffinement pour une approche générique des modèles au niveau système.- Un outil d'évaluation précise des performances linéaires et non-linéaires des circuit analogiques pour le raffinement des modèles niveau système et l'optimisation de la conception niveau circuit.- Une méthodologie de conception niveau circuit basée sur des outils de dimensionnement et d'évaluation des performances avec précision.- Un environnement de conception multi-niveaux unifiée appliqué aux systèmes mixtes avec une très forte interaction entre la simulation niveau système et la conception optimisée niveau circuit

Environnement de conception multi-niveaux unifiée appliqué aux systèmes mixtes

Ce travail se place dans le contexte de la conception, la modélisation et la simulation de systèmes hétérogènes contenant a la fois des capteurs, des composants analogiques, des composants numériques et des circuits RF.La seule manière de simuler un système avec une telle complexité avec un temps de simulation raisonnable est de faire une modélisation haut niveau.Cependant, pour que ce modèle haut niveau soit fiable, les modèles des blocs analogiques et RF doivent contenir une description précise des leurs imperfections.Dans ce travail nous proposons une méthode systématique pour la caractérisation et le raffinement des modèles des blocs analogiques et RF.Cette méthode est réalisée dans un environnement C++ base sur: - l'outil de simulation haut niveau SystemC-AMS- l'outil de résolution d'expression symbolique GiNaC- l'outil de synthèse de circuits intégrés analogique CAIRO+/CHAMSPour illustrer la validité de la méthode proposée, nous présenterons le modèle d'un nœud d'un réseau de capteurs sans fil avec une caractérisation automatique de certains blocs analogiques et RF.Les points suivant résument les contributions apportées pour ce travail.- La première implémentation d'un modèle analogique numérique mixte complexe avec le langage SystemC AMS: un nœud de réseau de capteurs sans fil.- L'introduction du raffinement pour une approche générique des modèles au niveau système.- Un outil d'évaluation précise des performances linéaires et non-linéaires des circuit analogiques pour le raffinement des modèles niveau système et l'optimisation de la conception niveau circuit.- Une méthodologie de conception niveau circuit basée sur des outils de dimensionnement et d'évaluation des performances avec précision.- Un environnement de conception multi-niveaux unifiée appliqué aux systèmes mixtes avec une très forte interaction entre la simulation niveau système et la conception optimisée niveau circuit.PARIS-BIUSJ-Mathématiques rech (751052111) / SudocSudocFranceF

Reperfusion injuries after prolonged limb ischemia

Limb revascularisation after prolonged ischemia is often associated with a local worsening of the muscular damage. Oedema, loss of muscle function, muscular necrosis and systemic disorders are the result of a sequence of local cellular events and systemic complications, which begin with the ischemic period and are aggravated by uncontrolled reperfusion. We present a typical case which reminds us that it is not enough to reverse ischemia. We must, futhermore, control the conditions in which reperfusion occurs.SCOPUS: sh.jinfo:eu-repo/semantics/publishe

Automatic Model Refinement of GmC Integrators for High-Level Simulation of ContinuousTime Sigma-Delta Modulators

Abstract—A Σ ∆ GmC integrator refinement flow is presented. The classically simplified GmC integrator small-signal model was upgraded to be extremely accurate by considering the complete transistor small-signal model. A circuit-level knowledge-based tool was used to execute the designer defined sizing procedure and to extract small signal parameters. By associating the symbolic transfer function to small-signal parameters, the flow, entirely implemented with C++, is able to compute poles and zeros to permit precise behavioral simulations. A 2 nd order Σ∆ modulator was chosen to visualize performance degradations while the specifications were not achievable. a1 K(s+z1)(s+z2) (s+p1)(s+p2

Modeling Heterogeneous Systems Using SystemC-AMS Case Study: A Wireless Sensor Network Node

Abstract — The paper presents a preliminary approach for the modeling and simulation of a simple but complete Wireless Sensor Network with two nodes using SystemC-AMS, an open-source C++ library dedicated to the description of heterogeneous systems containing digital, analog, RF hardware parts as well as embedded software. The WSN node, or mote, detailed herein consists of a physical sensor, a continuous time sigmadelta converter with its associated decimation filter, an ATMEGA128 8-bit microcontroller running the embedded application and a QPSK-based 2.4 GHz RF transceiver. The node has been designed to be interoperable with both the XBow MICAZ hardware platform and the TinyOS operating system in a near future. The paper starts with the structural description of the system as a hierarchical set of behavioural modules, then gives an insight on how multi-frequency simulation is handled in SystemC-AMS, and finally presents simulation results that are systematically compared with the Matlab reference in terms of accuracy and simulation time. I

Modeling and Refining Heterogeneous Systems With SystemC-AMS: Application to WSN

Abstract — The paper presents a system-level approach for the modeling and simulation of a paradigmatic Wireless Sensor Network composed of two nodes using SystemC-AMS, an open-source C++ extension to the OSCI SystemC Standard dedicated to the description of heterogeneous systems containing digital, analog, RF hardware IPs as well as embedded software. The paper is composed of three parts. The first part details the modeled WSN (physical sensor, sigma-delta ADC, ATMEGA128 8-bit microcontroller running the embedded application, QPSK-based 2.4 GHz RF transceiver), presents the corresponding implementation in SystemC-AMS, and gives an insight on how multi-frequency simulation is handled in SystemC-AMS. The second part shows how to introduce several RF designer specifications (noise figure, IIP3,...) into models and how to express them in SystemC-AMS. The third part proves that the combination of C++ and RF baseband equivalent dramatically reduces simulation time while keeping excellent accuracy and code readability. The paper concludes on the possibilities offered by this approach in terms of validation and optimization of heteregeneous systems through open-source simulation. I

Ancient split of major genetic lineages of European Black Pine: evidence from chloroplast DNA

International audienceThe European Black Pine (Pinus nigra Arn.) has a long and complex history. Genetic distance and frequency analyses identified three differentiated genetic groups, which corresponded to three wide geographical areas: Westerns Mediterranean, Balkan Peninsula and Asia Minor. These groups shared common ancestors (14.75 and 10.72 Ma). The most recent splits occurred after the Messinian Salinity Crisis (4.37 Ma) and the Early–Middle Pleistocene Transitions (0.93 Ma). The posterior ancestral population size (Na) is 260, 000–265,000 individuals. Each pool is further fragmented, with evidence of a phylogeographic structure (Nst > Gst) typ- ically observed in some natural populations from the Western Mediterranean region and the Balkan Peninsula. The labora- tory analysis was performed by fragment analysis—i.e. elec- trophoretic sizing of polymerase chain reaction fragments, combined with the sequencing analysis of 33 % of all individ- uals as a control. Intense sampling of chloroplast DNA poly- morphisms (3154 individuals and 13 markers: SNPs and SSRs) over the full area of the species’ natural distribution indicated moderate among-population variability (Gst(nc) ≤ 0.177) in various parts of its range. These results indicate that the natural populations have long migration his- tories that differ from one another and that they have been strongly phylogeographically affected by complex patterns of isolation, speciation and fragmentation. Long and varying climatic fluctuations in the region of the principal genetic group have been the probable cause of different forest com- munity associations with different successional patterns resulting in interglacial refugia vs. macro long-term refugia