PhD : selection by topics
Mathematics - Numerical analysis - Simulation
Biochemistry
Optics - Laser optics - Applied optics
Solid state physics, surfaces and interfaces
Biotechnologies,nanobiology
Biotechnology, biophotonics
Analytic chemistry
Electronics and microelectronics - Optoelectronics
Materials and applications
Thermal energy, combustion, flows
Mechanics, energetics, process engineering
Physical chemistry and electrochemistry
Medical imaging
Instrumentation
Electromagnetism - Electrical engineering
Radiation-matter interactions
Chemistry
Automatics, Remote handling
Nuclear physics
Ultra-divided matter, Physical sciences for materials
Neutronics
Biotechnologies,nanobiology
Biotechnology, biophotonics
Biochemistry
Materials and applications
Solid state physics, surfaces and interfaces
Electronics and microelectronics - Optoelectronics
Theoretical Physics
Ultra-divided matter, Physical sciences for materials
Chemistry
Study of the security properties of emerging Si technologies & devise of new countermeasures against physical attacks.
With the growing use of Commercial Off the Shelf products as micro-chips in embedded security devices, it is of utmost importance to design Integrated Circuits (ICs) based on technologies that can be ?intrinsically robust? against physical attacks like side-channel attacks, fault injections or even invasive reverse-engineering/modifications. Several technologies for low power high density IC designs are under development in the laboratories of the Leti. The aim of this thesis is to investigate about the security properties of those cutting-edge technologies (like FD-SOI, FINfet, TSV?): security characterisations of those technologies shall allow us either to devise how they can be used to devise new counter measures against physical attacks or to find out how to influence their development to make them ?intrinsically more robust? against such attacks.
See the summary of the offerArchitecture and Design of an Ultra Low Power Asynchronous Processor Core for Sensor Networks
After the blooming of ?internet for everybody?, is opening the new era of ?internet of things?, were everyday life objects will integrate a micro-system which will monitor, inform and alarm. Various applications are foreseen for these sensor networks: medical monitoring, industrial monitoring, environment sensing, home automation, etc. One of the main technical challenges is to design ultra-low power sensing node, to offer fully autonomous node, through energy harvesting or micro-battery. In this PhD, it is proposed to apply asynchronous logic design techniques (without clocking), in order to design an ultra-low power micro-controller core, adapted for these sensor networks applications. Asynchronous logic offers interesting properties for these applications such as: robustness to working conditions, intrinsic low power logic, efficient and fast wake up and sleep phases. In this PhD subject, the candidate will: - Propose a processor core architecture adapted to these sensor network applications, with innovative design solutions (instruction type, data encoding, adapted arithmetic), - Propose efficient power control mechanisms, including wake-up and sleep, in order to offer reactivity and computation at minimal energy level, and this using a wide voltage range, - Design the processor core using specific CAD tools for async. logic, targetting an advanced CMOS technology (such as FDSOI 20nm, offering low power & ultra-wide voltage range) - Participate to the core integration in a full system, for silicon fabrication, - Measure and compare performance results with state-of-the-art, - Valorize research outcomes through patents and scientific publications. The PhD work will take place within the LETI/DACLE/LISAN laboratory, which is designing digital architectures, with a strong focus on asynchronous logic and advanced CMOS technologies, and the PhD will benefit from expertises of other labs in order to interface with other sensor node elements (RF interface, sensing interface, energy harvesting, and embedded software).
See the summary of the offerOptimization of communication protocols and associated micro-architecture of optical networks on chip under thermal constraints
Considering ever-increasing bandwidth requirements between processors and memories in massively parallel architectures used in high-performance computing and servers in data-centers, the CEA-Leti institute is considering the use of optical networks between computing chips and memory chips on silicon interposer. In that perspective, it appears necessary to guarantee reliable electro-optical links between CMOS dies whatever the distribution of power supplies and temperature in the package. Indeed, the photonic modulators on silicon of small dimensions required for those optical communications show a large thermal sensitivity. Hence, this PhD thesis aims to propose thermal regulation mechanisms, calibration protocols for the electro-optical link depending of the signal quality, and several architectural and design counter-measures such as spatial and temporal redundancy, and dynamic reconfiguration of data encoding depending on the environmental conditions.
See the summary of the offerWireless transmission architectures and circuits in sub-THz band
This research work aims the fabrication of a wireless transceiver chain in the sub-THz frequency band. The aimed throughput of the future RF front end circuit is between 20 Gb/s and 30 Gb/s. The transceivers will be fabricated in Silicon technologies (advanced CMOS or BiCMOS) and will integrate the transmission antennas. As a first step, the frequency bands (120 GHz / 240 GHz) should be identified and the related regulations studied. The available CMOS and BiCMOS technologies will be characterized in order to adapt the transceiver architecture and the circuit design to such high frequency bands. Architecture and system level studies will be performed, coupled to potential modulation schemes in order to identify the most relevant system architecture for each used technology. Link budget calculation will be used for global system and building block specification. Finally, the system will be designed and fabricated in CMOS or BiCMOS technology. Le PhD candidate will use and/or develop simulation tools such as ADS, Fasyle, Matlab and CADENCE. A good knowledge is required on wireless telecommunication systems, Silicon integrated circuit design and microwave engineering.
See the summary of the offerRadiolocation Algorithms Adapted to High-Precision Ultra Wideband Rake Receivers Using Multiple Antennas
Making possible unprecedented user-centric services (monitoring/smart inventory of personal goods from a smartphone, context-aware indoor navigation, etc.), new radiolocation capabilities appeared in wireless networks are on the verge of modifying in depth our daily life and habits. This revolution might even be comparable to that of GSM cellular communications or GPS-based car navigation in the past. In this context, an Impulse Radio ? Ultra Wideband receiver (IR-UWB) endowed with multiple fingers (RAKE) has been recently integrated with success. The latter claims low consumption (a few 10s of mW in average), while enabling the detection of weak incoming signals and enjoying scalable data rates (<50Mbp) that depends on the targeted transmission ranges (up to several 100s of meters). One more particularity lies in the capacity to estimate precisely the arrival time (TOA) of transmitted pulses, without any high-speed sampling operation on the receiver side. This solution can thus theoretically provide peer-to-peer distance estimates between radio devices within a precision of a few centimetres. Using multiple antennas on both transmitter and/or receiver sides can also help to improve signal sensitivity ahead (and hence, transmission ranges accordingly), as well as to jointly deliver angles of departure/arrival to complement estimated arrival times. However, in most of indoor non-controlled operating conditions (radio device hold in the user's hand or in the pocket), propagation phenomena can play a harmful role on the final localization performance. Practically, the obstruction of radio links by bodies and/or walls, or even an unfavourable device attitude, can lead to significant errors on measured distances and finally on position estimates. But the time/space correlation of received multipath components, as well as the highly timely and localized nature of the most severe obstruction cases, can be beneficial to try to enhance performance. In this PhD work, the main contribution consists in theoretically investigating, designing and evaluating new radiolocation algorithms that could take profits from the specificities of such high-precision IR-UWB devices. In particular, significant multipath components resolved at the receiver fingers shall be exploited further. We will also consider deploying multiple antennas at fixed reference nodes (base stations), as well as at mobile terminals. One goal would be to guarantee performances equivalent to that of optimistic visibility cases. One side objective would be to provide new detection functions (obstructions, wrong device attitude or geometric ambiguities).
See the summary of the offerStudy of an ionization chamber of variable pressure for radiopharmaceuticals
The Laboratoire National Henri Becquerel (LNHB) of the Commissariat à l'Energie Atomique (CEA) is a national metrology laboratory for ionizing radiation. In this context it provides development, maintenance and the transfer of national reference for the international namely the Becquerel and the gray system units. Pressurised well type ionization chambers are used for the Becquerel unit transfer to users. These instruments (so called radionuclide calibrators) are widely used in the nuclear medicine services for activity measurements prior to its administration into patient for diagnostic purposes. LNHB has in charge the calibration of radionuclide calibrators for France. One of the nuclear medicine services difficulties is the access to calibration factors adapted to the clinical measurement conditions in terms of sample geometry. Thesis work consists on one hand in the supervision of the construction of the ionization chamber and in its measurement chain realisation. On the other hand, the work consists in the Monte Carlo simulation of the source-detector system in order to determine calibration factors for specific geometries (adapted do clinical conditions), in several conditions like nature and pressure of the detection gas (Argon, Nitrogen and xenon). Various packaging Radiopharmaceuticals (syringes, vials, ?) calculated calibration factors will then be compared to the experimental ones for three nature of detection gas under a specific pressure.
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