Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PhD : selection by topics

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Contactless electronics under high-temperature and radiation exposures

Département Architectures Conception et Logiciels Embarqués (LIST-LETI)

Laboratoire Intégration Gestion d'Energie Capteurs et Actionneurs

SL-DRT-20-0249

gael.pillonnet@cea.fr

New computing paradigms, circuits and technologies, incl. quantum (.pdf)

The objective is to design a new generation of contactless electronics to be robust to high-temperature and radiation expositions. Based on the recently introduced ?contactless electronics? paradigm, the PhD student have to define new mechanical structures and electronics schemes to operate in harsh conditions and to offer analog- and digital-operations. This study is based on a complete breakthrough proposal compared to the classical transistor-based electronics to overcome the inherent physical limit of transistor at high-temperature. The PhD student will propose, model and simulate electro-mechanical micro fabricated structures to validate the theoretical principle recently announced by some senior-scientists in our laboratory. The project involves multi-disciplinary study including microelectronics, electromechanical MEMS devices, solid-state physics and gives an excellent opportunity for PhD student to cover a large scientific scope.

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AI processing of time series for smart sensors

Département Architectures Conception et Logiciels Embarqués (LIST-LETI)

Laboratoire Infrastructure et Ateliers Logiciels pour Puces

01-10-2020

SL-DRT-20-0261

marielle.malfante@cea.fr

Artificial intelligence & Data intelligence (.pdf)

Today, sensors are used to acquire data of a given modality (acoustics, pressure, image, etc.). Usually, such data are stored before being analysed, for instance with machine learning methods. The relevant information is thereby extracted. A large variety of sensors and use cases can be considered: - Microphones for the automatic classification of acoustic landscapes, - Pressure sensors to study deformation and monitor various architectures (brides, dams, wind turbines, etc.), - Seismometers to detect signals warning of a seisms or of a volcanic eruption, - Smart watches or bracelets to detect stress phases, Etc. The issue of smart sensors consists in creating and designing sensors whose output is the relevant information, straightaway (see Fig. 1). Most of the time the raw signal no longer has to be transferred and stored. Smart sensors are a challenge in numerous fields, typically when sensors have to run autonomously in remote environments, or with limited power and storage access. For instance when studying acoustic landscapes pour environmental monitoring (forest, underwater areas, etc). IoT and wearable sensors are also targeted. Turning a sensor into a smart sensor presents a challenge at many levels. For instance, efficient AI methods to process the data need to be designed, with constraints in term of computation power and energy. Another challenge consists in building those analysis tools from small datasets, or from weakly supervised datasets. CEA is already conducting researches on those issues, and AI based methods are particularly relevant. This PhD subjects focuses on sensors recording time series: IMU, microphones, connected bracelets, etc. The core of the issue is to work on AI methods for time series, in one or several applicative fields. The PhD registers in a larger subject, namely AI reliability (anomaly detection, detection of events of class unseen during the training stage, etc.), but also the development of AI methods under labelling constraint. The topic is ambitious and several approaches are considered.

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Integration of piezoelectric-based power converters

Département Architectures Conception et Logiciels Embarqués (LIST-LETI)

Laboratoire Intégration Gestion d'Energie Capteurs et Actionneurs

SL-DRT-20-0286

adrien.morel@cea.fr

Cyber physical systems - sensors and actuators (.pdf)

The aim of this thesis is to integrate high-efficiency power converters based on resonating piezoelectric transducers. A large part of the work is to develop the integrated circuit to handle high switching frequency operation while maintaining an adiabatic energy transfer. Based on our recently published results [Pollet2019], the integration of the power stage and the control between phases paves the way of the miniaturization of the piezoelectric transducer using microelectronics process. The PhD student will cover the sizing, IC design, electro-mechanical characterization and feedback control of miniaturized piezoelectric-based power converters. [Pollet2019] B. Pollet et al., A New Non-Isolated Low-Power Inductorless Piezoelectric DC?DC Converter, Trans. on Power Electronics, 2019.

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Embedded AI for the semantic interpretation of a probabilistic environment model

Département Architectures Conception et Logiciels Embarqués (LIST-LETI)

Laboratoire Infrastructure et Ateliers Logiciels pour Puces

01-10-2020

SL-DRT-20-0291

tiana.rakotovao@cea.fr

Artificial intelligence & Data intelligence (.pdf)

The perception and modelling of an environment is a major issue when developing autonomous vehicles. How to model the surroundings of a vehicle? How to detect and identify the various obstacles? What about free spaces, and areas safe to drive on? Which sensor combination is the most appropriate to reach an exhaustive description and modelling of the environment? Those questions all have beginnings of answers, but still remain open and not yet solved. There also is a strong constraint regarding the need for embedding systems, which is one of the CEA focuses. Which processing and analysis can be considered while targeting embedded systems? Occupancy Grid is a model used to represent the surroundings of a vehicle and present various advantages. Several sensors of various modalities are used to compute the grid: each modality brings a specific information. For instance, infra-red is efficient by night, LIDAR offers a 360° field of view but is not robust to bad weather conditions, in which case a radar would be preferable. Ultrasound sensors on the contrary are used to analyse very short distances. CEA has developed approaches based on Bayesian fusion to produce SigmaFusion library. SigmaFusion is a tool to fuse the information of different sensors to produce an occupancy grid, which evolves with time. A strong point of SigmaFusion is the computing optimization: the technology is particularly efficient and competitive under strong embedded constraints (low cost integration with low energy consumption on micro-controller certified for critical task for the automotive market). An issue currently addressed is the use of EdgeAI methods to gain a semantic interpretation of an occupancy grid. A typical question is the level of knowledge and interpretation that can be reached while respecting the embedding constraint. Is it possible to detect the object evolving in a grid automatically, in real time and at low energetic cost (pedestrians, cyclists, cars, etc.)?

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Model of energy losses due to fouling of bifacial PV modules and the reduction in induced albedo.

Département des Technologies Solaires (LITEN)

Laboratoire Systèmes PV

01-10-2020

SL-DRT-20-0303

eric.pilat@cea.fr

Solar energy for energy transition (.pdf)

The generation of energy from solar technologies becomes more and more important and consequently the serious consideration of a problem, the soiling Today, the unit of measurement is no longer the Giga Wh but the Tera Wh and, therefore, the smallest percentage of losses can generate a considerable economic deficit. In order to reduce the cost of the energy produced (LCOE), the players are looking to locate their installations in the sunniest, arid and unfortunately often very dusty regions. Finally, a promising new technology of PV cells, capable of capturing photons on both sides, has recently emerged and requires a fundamental review of the soiling approach, taking particular account of variations in soil albedo. The context of the study is favorable, because motivated by an increasing number of patents and articles, strong pressure on the cost of cleaning and water consumption, new applications such as agro-PV particularly sensitive. The main objective of the doctoral student is to develop algorithms for calculating the impact of soiling from the characteristics of the PV fields, data measured on the systems and taking into account the influencing environmental parameters. He identifies the best measurement methods and instruments to quantify the level of soiling. The scientific difficulty lies in the diversity of the materials concerned and the challenge consists in apprehending and reproducing multiple physico-chemical phenomena involved in the process of accumulation of soiling.

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Electrochemical deposition of insulating polymer films

Département des Plateformes Technologiques (LETI)

Laboratoire

01-10-2020

SL-DRT-20-0308

paul.haumesser@cea.fr

Emerging materials and processes for nanotechnologies and microelectronics (.pdf)

The electrohoretic deposition is a well known technique to form polymeric coatings with a variety of materials such as polyetherimide (PEI). This technique usually requires the application of several (tens of) volts. Under such conditions, electrochemical reactions occur at the electrodes, such as solvent decomposition, that promote polymer precipitation at their surface. Recent results suggest that these electrochemical reactions are sufficiently active at much lower overpotentials (below 3V). This would enable deposition processes under mild conditions with improved control over the film properties. In this thesis, the mechanisms at play during the deposition of PEI under such mild conditions will be studied, with the aim of developing a process suitable for the fabrication of capacitors with high breakdown voltage. This approach will also be extended to other insulating polymers compatible with healthcare applications (such as packaging of wiring circuits for implant systems) or to hydrophilic and/or porous polymers for the encapsulation of biologic structures (cells, enzymes, bacteria) or cell filtration in biochips.

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