Current Work: Energy Efficient Control

Since December 2015, I am a research associate in the Departement of Computer Science of the University of Liverpool, where I study the desing of energy efficient circuits with Sven Schewe and Dominik Wojtczak. This work is funded by the EPSRC project Energy Efficient Control.


Previous Work: Control for Clouds

Between June 2013 and November 2015, I was a member of the SUMO team at INRIA Rennes. Until June 2013, I was a postdoctoral fellow in the ERODS team (formerly known as the Sardes teamLIG, INRIA Grenoble); I was also a member of the Ctrl-A working group. Both positions were related to the Ctrl-Green project, in which reactive control techniques are investigated for the design of autonomic systems (i.e., software whose role is to automate system administration tasks). In this context, my primary objectives were twofold:

Reactive Control Techniques for Autonomic Management Systems

My first aim was to propose a new approach for designing autonomic systems. Indeed, such systems usually involve several pieces of software designed independently from each other. As a consequence, they may take inconsistent decisions when executed in a non-coordinated manner. Using reactive control techniques, and especially synchronous languages and discrete controller synthesis, provides means for static enforcement of global properties, such as the avoidance of inconsistent decisions. This work has been done with Éric Rutten, Noël De Palma, and Soguy Mak-Karé Gueye.

Journal Articles

Discrete Controller Synthesis for Infinite State Systems

In relation with the previous work, my second goal was to augment actual discrete controller synthesis techniques to handle quantitative aspects of managed systems (e.g., power consumption, workloads), as well as to be able to enforce properties about such quantities. In effect, existing techniques and tools performing discrete controller synthesis on synchronous programs (Sigali) need to be extended in order to handle infinite state systems (e.g., programs comprising real or integer variables). I worked (and am still working) on such extensions with Hervé Marchand.

These investigations have led to the development of the tool ReaX. It is distributed as part of the Reactive System Verification and Synthesis ToolKit (ReaTK), available in my OPAM repository.

Papers


Previous work: PhD

"Tout commence par une interruption." (Everything starts with an interruption.), Paul Valéry (perverted quote).

I prepared my PhD in the Synchrone team at the Verimag laboratory.

Synchronous Programming of Device Drivers for Global Resource Control in Embedded Systems

During my PhD, I worked about the design of software for embedded systems. The hardware platforms usually employed in these systems provide a limited amount of memory, computational power and energy. The software they execute is then constrained by such limited resources. Usual applications involve further objectives, such as reactivity and lifetime. In addition, these platforms comprise shared resources like buses or even the energy provided by a battery. Hence, global properties concerning the whole platform must be enforced, for instance to control concurrent accesses to a bus or power consumption. As device drivers are commonly developed individually, the knowledge necessary to implement global control policies is distributed among several pieces of software.

I proposed a global control approach, based on a centralized view of the devices' states. Built upon para-virtualization principles, it operates on the hardware/software interface. It involves a simple adaptation of the guest operating system, to communicate with the hardware via a control layer. The control layer itself is built from a set of simple automata: the device drivers, whose states correspond to functional or power consumption modes, and a controller to enforce global properties. All these automata are programmed using a synchronous language, and compiled into a single piece of sequential code.

I defended my PhD on March 12, 2012. My advisors were Florence Maraninchi and Laurent Mounier.

Journal Article

Papers

Poster


Previous Work: Master, etc.

Below are presented the research that I have done before starting my PhD.

System-level Modeling of Embedded Control Systems: A Case Study from the Automated Transfer Vehicle

Dynamic Memory Management in Real-Time Java Applications