Open PhD position in machine learning and signal processing at Qarma, LIF, Marseille

We are looking for candidates for a three-year funded PhD entitled “Acceleration of greedy algorithms for signal modeling – Theory and applications” at Qarma, LIF, Marseille. See offer below, also available at http://www.lif.univ-mrs.fr/~vemiya/research/PhD_offer_Greta_Qarma.pdf .

Acceleration of greedy algorithms for signal modeling – Theory and applications

PhD position

Supervisors: Valentin Emiya and Liva Ralaivola, Laboratoire d’Informatique Fondamentale de Marseille, France

This PhD position is funded for three years.

PhD description

Keywords. Algorithms, machine learning, signal processing, optimization, sparsity.
Abstract. This PhD project addresses theoretical and applicative aspects of emerging sci- entific topics at the interface between machine learning and signal processing. The goal is to design new greedy algorithms, focusing on their speed.

Scientific context. Sparse approaches can model a wide range of signals – images, sounds,
biomedical signals, and so on – and their intrinsic structures. They benefit from a solid theory and efficient algorithms. These modern techniques are used in a growing number of applications such as signal compression and coding, source separation, inpainting or pattern recognition.
Goal. Today’s algorithms are limited by their computational complexity. As a result, they are slow and cannot handle large volumes of data. In practice, this is a major limitation since applications are more and more demanding e.g. in terms of real time constraints or fine 3D discretization. Recent theoretical results have opened new directions for the design of fast algo- rithms. In the case of greedy algorithms such as Matching Pursuit, preliminary theoretical and experimental results have been obtained at Laboratoire d’Informatique Fondamentale de Mar- seille (LIF). The goal of this PhD project is to develop this topic by designing new algorithms and validating them with theoretical and practical considerations. Several applications will be addressed such as audio inpainting and underwater acoustic imaging.

Tentative workflow. First, the PhD candidate will get familiar with sparse models and algorithms, and work on algorithmic ideas emerging from the preliminary results obtained at LIF. The research will be pursued in both the theoretical and the applicative direction, the focus being more on one or the other, depending on the candidate’s profile.

Collaborative context. The PhD project is at the core of a French ANR (national fund) project called GRETA (Greediness – theory and algorithms) initiated in 2012 by LIF, LATP and INSA Rouen. The PhD candidate will work within an active research group and will have the opportunity to travel inside and outside France, for conferences and collaborations.
Supervisors: Valentin Emiya and Liva Ralaivola, Qarma team, LIF.

Team and scientific environment
The PhD candidate will join the Qarma team at Laboratoire d’Informatique Fondamentale de
Marseille, which is a joint research lab between CNRS and Aix-Marseille University. The Qarma team (about twelve researchers) dedicates its activities to statistical machine learning theory and applications to signal processing and multimedia indexing.

The PhD candidate will also work with Sandrine Anthoine, a researcher at the neighboring mathematics lab. LATP. Other scientific exchanges will be possible locally and nationally (with the partners of the GRETA project, Rémi Gribonval at INRIA Rennes, Laurent Daudet at Paris 7 University, Jacques Marchal at Paris 6 University).
Required background

The applicant must have at least one of the following profiles: maths, signal processing, machine learning, computer science.

Salary
The candidate will be hired for three years with a standard French PhD contract (contrat doc- toral). The net salary is 1374.21 euros per month including health insurance. Teaching or consulting opportunities may be added to the contract if the candidate wishes.

Application
Applicants should contact Valentin Emiya and Liva Ralaivola (firstname.lastname@lif.univ-mrs. fr) as soon as possible. Additional information about the PhD project will be available at this stage.
The application must be sent by email to Valentin Emiya and Liva Ralaivola according to the schedule below. It must include

• a cover letter explaining the applicant’s motivations,
• a resume,
• a transcript of the Master degree marks (or equivalent), • optional: recommendation letters or referees contacts.

The selected applicants will be interviewed, either in the lab or by phone.
Schedule (subject to changes):

• June 30, 2012: deadline for sending the application.
• July 10, 2012: end of the interviews and announcement of the results. • October 1st, 2012: beginning of the contract.

Contact
Valentin Emiya and Liva Ralaivola, firstname.lastname@lif.univ-mrs.fr.