Methodologically, the ODISSE project is at the crossroads of inverse problems for partial differential equations (PDE) and observer theory. These two disciplines have a long and rich history of interactions between them and their overlap is becoming more and more important. The ODISSE project proposes fundamental/theoretical contributions in observer design to reconstitute online missing parameters in some dynamical systems described by PDE. Indeed, to analyze, monitor, control or understand physical or biological phenomena, the first step is to provide a mathematical modeling in the form of mathematical equations that describe the evolution of the system variables. Some of these variables are accessible through measurement and others are not. One of the problems in control engineering is that of designing algorithms to provide real time estimates of the unmeasured data from other measured variables. These estimation algorithms are called state observers and are used in many devices. The implementation of such estimators in the context of hyperbolic PDE systems, which are infinite-dimensional systems in the sense that the system's state belongs to a functional space of infinite dimension, is a topic of great interest both from the practical and theoretical points of view. Systems modeled by hyperbolic PDE, that can be of order one or two, correspond to propagation phenomena and appear in many physical contexts and industrial applications. The ODISSE project aims at developing rigorous methodological tools for the design of estimating algorithms for infinite-dimensional systems governed by hyperbolic PDE, with a particular focus on two typical equations: transport equations (hyperbolic PDE of order one) and wave equations (order two). For this purpose, observability properties of this type of PDE systems will be investigated and novel tools for analyzing their estimations will be developed. Based on the peculiarities of each field, we try several challenges that could help in solving some observation problems for hyperbolic PDEs: 1- Find a way to connect the notion of identifiability in inverse problems and that of observability in observer design. 2- For identifiable parameters in the sense of inverse problems, find a way to synthesize a robust and online estimation algorithm (an observer). 3- Find means to incorporate recent advances in the field of observer designs for nonlinear finite dimensional systems. Conversely, study the possibility of using tools from infinite dimensional systems for observer synthesis for finite dimensional systems. 4- Implement the proposed algorithms and perform convergence analysis of the discretized (finite dimensional) systems toward the continuous initial (infinite dimension) systems. These challenges will be addressed in the ODISSE project through a close collaboration between researchers in applied mathematics and control theory from the community of inverse problems and observers design. Several control applications will serve as a test bed to evaluate practical relevance of the theoretical tools to be developed. More specifically, we will work out analysis and design of observers for the concrete processes : batch crystallization processes, polymerization processes and transient elastography.

Traumatic Brain Injury (TBI) is the leading cause of disability among young adults in developed countries. TBI can lead to irreversible brain damage and debilitating neurological deficits, especially in severe cases. Few developments have been observed in terms of therapeutic or pharmacological treatments in recent years due to the heterogeneity of lesions which is a complex factor for clinical trials. Current strategies rely mainly on rehabilitation and mechanisms of brain plasticity. These are very limited. As a result, strategies based on cell-based therapies could open the way to new recovery possibilities and lead to a significant reduction in public health costs. Today, simply cell-based strategies have shown their limits: high mortality, low regenerative power. RECOVER is an innovative project aimed at achieving brain repair in a preclinical model of TBI by developing a therapeutic strategy using a combined approach: 1 / cell-based and 2 / based on 3D bio-implants. The project focuses on the repopulation of the lesioned area. In order to replace the extracellular matrix of brain tissue, we have developed an innovative synthetic hydrogel that is suitable for 3D cell culture of neuronal cells. In order to replicate the architectures of the cerebral cortex, an oriented material will be used to guide neuronal cell cultures in 3D. An innovative source of cells is proposed from biopsies of peripheral nerve tissue. It will allow translation into the clinic by autologous transplant. The tissue connections will be studied in vivo in longitudinal optogenetics implemented in MRI (Magnetic Resonance Imaging) during classical functional and in-situ MRI evaluations and at the end of the experiment after sacrifice by histopathological and immunohistochemical analysis of grafted brains. Behavioral tests used for the evaluation of motor function recovery will also be performed. This project is supported by the strong expertise of the candidates on three different and convergent themes: cellular therapy and functional evaluation (ToNIC), hydrogels (IRMCP) and 3D architectures or "scaffolds" (LAAS) thus opening a window opportunity to improve translational research on TBI. The last partner (LabHPEC / ENVT) has the expertise for histopathological assessment of the fate of in situ cell-bioimplants as well as early preclinical safety studies (biocompatibility of materials, local tolerance) of Innovative Drugs and Technologies in a GLP regulatory environment. Beyond TBI, this project is part of a broader research program focusing on neurological disorders following multifactorial brain or spinal cord injury. Indeed, our brain regeneration strategy is applicable to spinal cord injury, brain injury after a stroke, and to damage related to degenerative diseases.

Power electronics is a key technology to the energy transition. However, power converter design techniques are function-defined, resulting in a long and costly development process yielding non-reusable solutions. A software-defined approach, focused on repairing, reprogramming and refurbishing is possible. This approach is called planned perennity. The central problem to perennial assets is aging. In the case of power electronics, it is well known that different control algorithms will impose different thermal stresses in active and passive components. It is thus essential to find a mean of keeping track of a perennial product usage history and integrate this history in its control. The DataPower project proposes the creation of an online data platform that will gather the converter history, create its digital twin by combining model-driven control algorithms with data-driven machine learning techniques and study the best approaches to compensate this aging history for software defined power converters. This open online platform will provide the means to study several use cases using the same standardized open-source power electronics hardware. Its main contribution will be on the field of machine learning for power electronics, specifically on their preventive maintenance. The datasets acquired during the project will be used to create an open database of power electronics and systems applications. Collected datasets will constitute a database kernel that is expected to grow even beyond the project completion, creating a diverse community with both industrial and researchers members.

3D-BEAM-FLEX project aims at demonstrating the self-writing of continuous and flexible single-mode waveguides between VCSELs (Vertical-Cavity Surface-Emitting Laser) arrays and single-mode optical fibers in order to improve the photonic integration of these laser sources in high-speed optical interconnects ms at 850nm (datacom) and at 1.31 and 1.55µm (telecom, WDM). The tolerances on VCSEL-to-fiber coupling are indeed very tight, especially in single mode configuration, which currently needs long and expensive pre-alignment steps. In addition, the realization of efficient and truly compact optical links requires the redirection of the beam emitted by the VCSELs in the horizontal plane of the fibers and thus, the hybridization of 3D micro-optical elements by complex and non-collective assembly or in situ fabrication methods. To overcome all these barriers, the 3D-BEAM-FLEX project proposes to explore the mechanisms of self-writing in photopolymers and to exploit them to develop an innovative two-step photofabrication process in NIR and UV ranges. Thanks to both fundamental work (understanding of photochemical mechanisms, development of formulations sensitive at 0.85, 1.31 and 1. 55µm, analysis of the created index gradient, opto-mechanical design of the waveguide) and applied (demonstration of an efficient flexible single-mode link, analysis of the self-compensation of initial misalignments, demonstration of 90° beam redirection and multichannel fabrication, study of the resistance to optical flux) and by exploiting innovative 3D additive manufacturing techniques for the integration of the self-written link in a compact optical module, we will demonstrate that this simple and generic approach, applicable in a post-processing step, leads to an optimal coupling while relaxing the stringent tolerances on devices pre-alignment. To carry out this project, 3D-BEAM FLEX brings together a complementary consortium composed of two research institutes, LAAS-CNRS in Toulouse and IS2M-CNRS in Mulhouse, covering the fields of VCSEL sources and their photonic integration, photochemistry and microfabrication, as well as additive manufacturing by 3D printing. This cross-disciplinary expertise will enable the proposed concept to be demonstrated, with spin-offs both on fundamental and applied levels, with the development of new materials and the realization of compact optical links for data communications at several wavelengths and to a larger extent for miniaturized optical sensors.

The GeSPAD project is devoted to achieve a major breakthrough in the development of the next-generation of Single Photon Avalanche Diodes (SPAD), a high-sensitivity optoelectronic detector with many applications in X-ray tomography, biochemical sensors, DNA/protein microarray scanning, engine/turbine design, aids for disabled people, high-sensitivity and low-light cameras. In the near future, arrays of low-area SPADs will be employed for new applications in the Internet-of-Things such as user detection in smart wearable devices or in the optimization of long distance ranging for autonomous car applications. Today’s market is dominated by silicon-based SPADs, whose sensitivity is limited to photon wavelengths lower than 1100 nm. However, in order to improve depth accuracy in LiDAR systems it is highly desirable to shift the operation wavelength from 900 nm to 1500 nm, thus allowing the use of higher laser powers in compliance with eye-safety specifications. From an industrial perspective, the germanium option is a promising solution for integration on conventional CMOS process, but significant efforts in terms of technology development are needed, and a clear benchmark of the Ge-SPAD performances against III-V and Si-based devices is still missing. The main objective of GeSPAD is to assess novel designs of germanium-based SPAD devices, matrices and circuits and to benchmark them with their III-V and silicon counterparts. The devices designed within this project will feature enhanced infra-red photon detection probability (high quantum efficiency for wavelengths around 1310-1500 nm) as well as low dark count rates, noise and jitter. To attain this objective, Ge-based SPADs will be inspected at all possible levels, going from material properties through device physics until circuit optimization. This project will combine advanced characterization techniques on industrial Ge-based prototypes with multi-scale predictive simulation tools, and efficient quenching circuit design. The consortium will be composed by three academic laboratories and an industrial partner, STMicroelectronics, which is one of the major CMOS-SPAD producer in the world, and intends to maintain its leadership by investing in disruptive technologies. The partners are expert in different skills and will adopt complementary methodologies: C2N (coordinator) will study the device physics of SPADs by addressing full-band quantum transport simulations and time-dependent simulations with the particle Monte-Carlo method; LAAS will perform ab-initio calculations on defect properties in Ge and Si/Ge heterostructures as well as their photoluminescence spectroscopy; Lab. Hubert Curien will develop spice models for devices and circuits; STMicroelectronics will provide the electrical characterization of in-house devices as well as TCAD simulations to optimize the SPAD architecture. GeSPAD will have multiple repercussion on the community. From an industrial perspective, it will contribute to the design of the next generation of SPAD architecture and will very probably result in several patents. From an academic perspective, the clarification of the scientific problems here addressed will permit to gain a deeper understanding of the physics of optoelectronic devices and will result in publications in international journals and conferences. Finally, it will facilitate the creation of a French community working around SPADs.