Error Coding Driven Synthesis of Combinational Circuits from Unreliable Components
With the advent of nanoelectronics, the reliability of the forthcoming circuits and computation devices is becoming questionable. Indeed, due to huge increases in density integration, lower supply voltages, and variations in the technological process, MOS and emerging nanoelectronic devices will be inherently unreliable. As a consequence, the nanoscale integration of chips built out of unreliable components has emerged as one of the most critical challenges for the next-generation electronic circuit design. To make such nanoscale integration economically viable, new solutions for efficient and fault-tolerant data processing and storage must now be invented.
This post-doctoral position aims at investigating innovative fault-tolerant solutions, at both device- and system-level, that are fundamentally rooted in mathematical models, algorithms, and techniques of information and coding theory. Investigated solutions will build on specific error correcting codes, able to provide reliable error protection even if they themselves operate on unreliable hardware. The goal is to develop the scientific foundation and provide a first proof-of-concept, as an essential condition for bringing about a paradigm shift in the design of future nanoscale circuits.
Developement of a simulation platform for the energy systems
The evolution of power systems towards smart-grids, including a high share of renewable generation which can be combined with storage systems, lead to an increased complexity for designing and optimizing these systems. This leads to a need for new modeling and simulation tools, which have to manage different energy sources, different energy vectors and different technologies for energy conversion. Moreover, such simulation tools will be used to optimize the system sizing and to design energy management strategies.
The objective of this project is to design the software architecture for the simulation platform, which will be in ad equation to the previously mentioned needs. Such software will be organized in order to maximize the transfer towards industrial partners. The software will be able to support multi-energy systems, and will leave the possibility for the user to implement its own component models or energy management strategies.
The project is focused on the simulation platform architecture, and on the architecture model. This architecture will be used as a base for the development of a software. The objective of the given project is not to cover all the applications but rather to validate the architecture through a given application.
Development and characterization of concentrator photovoltaic (CPV) receivers for high-efficiency CPV modules
Concentrator photovoltaics (CPV) arises as a promising technology capable of economically justify the use of highly efficient (and highly expensive) monolithically stacked multijunction solar cells (MJSC). CPV takes advantage of low-cost optical elements, such as mirrors or lenses, to capture the sunlight and concentrate it into small-size cells, exchanging solar cell surface by optical elements. This technology, which is at an industrial stage, uses state-of-the-art triple junction (3J) solar cells with efficiencies up to 45%.
The postdoc position here proposed will deal with novel architectures of CPV receivers conceived from high-efficiency MJSC that will be integrated in next-generation CPV modules. The research engineer will also need to learn how to characterize these systems, for which he/she will use the tools available at the CPV Lab at INES (CEA). Novel characterization techniques may also be required.
The candidate must have a M.S. in Physics or Engineer with specialization on solid state physics, electronics, electrical engineering, mechatronics or similar. He/she must be a PhD, preferably in the field of photovoltaics and particularly on CPV. Good language skills and laboratory experience are required.
Robust path-following solvers for the simulation of reinforced concrete structures
Path-following procedures are generally employed for describing unstable structural responses characterized by ``snap-backs'' and/or ``snap-troughs''. In these formulations, the evolution of the external actions (forces/displacements) is updated throughout the deformation process to fulfill a given criterion. Adapting the external loading during the calculation to control the evolution of the material non-linearities is helpful to obtain a solution and/or to reduce the number of iterations to convergence. This second aspect is of paramount importance, especially for large calculations (at the structural scale). Different path-following formulations were proposed in the literature. Unfortunately, an objective criterion for choosing one formulation over another for the simulation of reinforced concrete (RC) structures (in the presence of different and complex dissipation mechanisms) still needs to be made available. The proposed work will focus on the formulation of path-following algorithms adapted to simulate RC structures.
ACCELERATING a DSN SWEEP KERNEL ALGORITHM FOR NEUTRONICS BY PORTING ON GPU.
In the framework of the Programmes Transversaux de Compétences (PTC or literally Cross-XXX Programme), the DES/ISAS/DM2S/SERMA/LLPR and the CEA-DIF are both working on the porting of deterministic neutron transport codes on GPU.
The DM2S within the Energies Direction (DES) is responsible for research and development activities on the numerical methods and codes for reactor physics, amongst which the APOLLO3® code. The neutronics laboratory of CEA-DIF is responsible for developing tools for deterministic methods in neutronics for the Simulation programme.
These two laboratories are actively preparing for the advent of new generation of supercomputers where GPU (Graphical Processing Units) will be predominant. Indeed, the underlying numerical problems to be solved along with the working methodology as well as the conclusions and experience which will be obtained from such studies may be rationalised between both laboratories. Thus, this work has given rise to this postdoctoral position which will be common to both teams. The postdoctoral researcher will be formally based at SERMA at CEA Saclay, with nevertheless regular meetings with the CEA-DIF scientists.
The postdoctoral research work is to study the acceleration of a toy model of a 3D discrete ordinates diamond-differencing sweep kernel (DSN) by porting the code on GPU. This work hinges on porting experiments which have previously been carried by both teams following two different approaches: a ‘’high-level’’ one based on the Kokkos framework for DES and a ‘’low-level’’ approach based on Cuda for CEA-DIF.
Production of green hydrogen and ammonia from offshore energy
This subject is dedicated to the high potential of offshore wind power in the high seas, where it seems extremely complicated and expensive to install an electric transmission to a continental grid. In addition, the IMO, a United Nation agency that is responsible for environmental impacts of ships, adopted ambitious targets to reduce greenhouse gas (GHG) emissions from marine shipping. The IMO plan regulates carbon dioxide (CO2 ) emissions from ships and requires shipping companies to halve their GHG emissions by 2050 (compared to 2008 levels).
Different ways are being explored in order to identify the best low-carbon fuel that will be able to power new marine propulsion systems without GHC emissions (and others polluants like Sox, Nox…).
Hydrogen combined with a fuel cell is a good option for small application (fishing boat…). However, issues associated with hydrogen storage and distribution (low energy density) are currently a barrier for its implementation for large and massive marine application which drivess 80–90% global trade, moving over 10 billion tonnes of containers, solid and liquid bulk cargo across the world’s oceans annually.
Hence, other indirect storage media are currently being considered. Of these, ammonia is a carbon free carrier which offers high energy density. First studies and demonstration projects show that it could be used as a fuel coupled with a new generation of high-temperature fuel cells (SOFC) or internal combustion engines.
This project focuses on the green ammonia production on a high seas platform including an offshore wind farm that use renewable electricity to first generate hydrogen from water (via electrolysis) and nitrogen from air and then combine both in a Haber-Bosch process to synthesize ammonia. The objective is to develop modeling tools (Modelica / Dymola environment) in order to build, simulate and optimize "wind to ammonia" systems and energy management solutions to minimize the production cost of ammonia.
Intégration CMOS à canal dual en technologie FDSOI : comparaison "enrichissement en Ge" vs. "Epitaxie localisée"
LETI is a major laboratory in the european microelectronics research, especially in the thin film FDSOI research (Fully Depleted). We propose innovative solutions for the next ITRS roadmap generations (sub 22nm), such as the integration of ultrathin Silicon-Germanium (SiGe) layers in the channel of p type transistors (in order to increase the hole mobility, and to adjust the threshold voltage of pMOSFETs).
The first results show significative gains for hole mobilityy and Vth,p tunning (C. Le Royer et al. ESSDERC 2010, IEDM 2011) but also for basic circuits (L. Hutin et al. IEDM 2010).
In order to further improve the Fully Depleted CMOS DualChannel integration, it is necessary to quantify in details the advantages and the possible drawbacks (form the process and from the electrical performance point of view). LETI wants to compare the two following approaches for SiGe based pMOSFETs (cointegrated with SOI nMOSFETs featuring 6nm body thickness):
.SiGe/SOI hetrostructures ("Localized SiGe epi" on SOI)
.SiGe-On-Insulator ("localized Ge enrichment" on SOI)
Other issues have also to be considered such as the initial substrate (SOI, sSOI) or the Ge content in the SiGe layer…
Kinetic study of biocide effect in nanocellulose_based food film
This project will study the kinetic of biocide effect of a nanocellulose-based film food. The main aim is to graft Ag and/or ZnO NPs on and inside halloysite particles that have a characteristic shape of twisted sheets and therefore could acting as NPs tanks. The localization of NPs outside halloysite could induce a fast biocide effect with limited duration whereas the internal grafting could produce longer biocide effect. This project gathers all steps from the film food synthesis, its nanocharacterization to the evaluation of its toxicological effect on bacteria. The final goal is to find one or many halloysite functionalizations allowing to extend the biocide effect in film food and to transpose it to other types of materials.
Silicon nanowire elaboration for microelectronic applications
In order to realize high capacity integrated capacitor, one approach consists in developing electrode with high specific surface. In this work, we propose to perform capacitor integrating silicon nanowires. The first part of this study will be devoted to the understanding and to the optimization of Si nanowires CVD growth process. In parallel, properties of nanowires obtained by electrochemical silicon etching will be assessed and will be compared to CVD nanowires characteristics. According to the electrical performances, different strategies (metallization Silicuration…) will be envisaged in order to enhance their electrical conductivity.
Neutronic thermal-hydraulic coupling in heterogeneous Sodium Cooled Fast Reactor (SCFR)
Within the frame of ASTRID (Sodium cooled Fast Reactor) prototype development, update of calculation methodologies using new generation of codes benefiting from High Performance Computing (HPC) and advanced coupling capabilities is underway. These methods are expected to be integrated in ASTRID safety demonstration. In particular, development of coupled neutronics/thermal-hydraulics/fuel mechanics methodologies during accidental transients is underway.
Coupling Neutronics and thermal-hydraulics in double phase flow conditions (either sodium + vapor sodium or sodium + other gaz) can be used for:
• Loss of Flow transients (LOF, sodium + vapor sodium)
• Gas insertion transients.
This coupling is of special interest with cores strongly relying on axial leakage for safety consideration (like CFV cores [ICAPP11]).
The work proposed is to further develop the implementation of 3D coupling with state of the art CEA codes (APOLLO3, FLICA, CATHARE, TRIO etc.) to analyze the two type of transients stated above.