CITI Talk: “Distributed Hypothesis Testing over Multi-User Channels”, Prof. Michele Wigger (Telecom ParisTech), 10am, amphitheater Émilie du Châtelet (Marie Curie Library-INSA de Lyon)

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As part of the internet of things (IoT), the number of sensor nodes that wish to communicate with each other has exploded and is expected to further increase dramatically. Such an increase of communication devices inherently leads to involved communication and hypothesis testing scenarios, and thus calls for new coding and testing strategies. The talk presents new strategies and corresponding error exponents for different network scenarios, and it proves information-theoretic optimality of the proposed strategies in some cases. Special attention is given to scenarios where information collected at a sensor is desired at multiple decision centres and where communication is multi-hop involving sensor nodes as relays. In these networks, sensors generally compete for network resources, and relay sensors can process received information with sensed information or forward intermediate decisions to other nodes. Depending on the studied error exponents, some of these intermediate decisions require special protection mechanisms when sent over the network. The talk is based on joint work with Sadaf Salehkalaibar, Roy Timo, and Ligong Wang.

CITI Talk: “Coding for Cloud-RAN Downlink Channels”, Prof. Gerhard Kramer (TU Munchen), 9am, amphitheater Émilie du Châtelet (Marie Curie Library-INSA de Lyon)

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The downlink of a cloud radio accessnetwork (C-RAN) architecture can be modeled as a diamond network. The baseband unit (BBU) is connected to remote radio heads (RRHs) via fiber links that are modeled as rate-limited bit pipes. Bounds on the rates for reliable communication are evaluated for single-antenna RRHs. A lower bound is based on Marton’s coding, which facilitates dependence across the RRH signals. An upper bound uses Ozarow’s technique to augment the system with an auxiliary random variable. The bounds are studied over scalar Gaussian C-RANs and are shown to meet and characterize the capacity for interesting regimes of operation. The bounds are also evaluated for an abstract model: a noise-free binary adder channel (BAC). The capacity of the BAC is established for all ranges of bit-pipe capacities, which seems to yield a new combinatorial result on sum sets. This work is based on joint work with Shirin Saeedi Bidokhti and Shlomo Shamai.

CITI Talk: “Statistical Learning via Information Bottleneck”, Prof. Abdellatif Zaidi (Université Paris-Est Marne la Vallée), 4pm, room TD-E

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We connect the information flow in a neural network to sufficient statistics; and show how techniques that are rooted in information theory, such as the source-coding based information bottleneck method can lead to improved architectures, as well as a better understanding of the theoretical foundation of neural networks, viewed as a cascade compression network. We illustrate our results and view through some numerical examples.

CITI Talk: “Body Impedance for Authentication, Key Generation and Device Pairing”, Kasper Rasmussen, Associate Professor (University of Oxford), December 8th 10:30, RobIoT room

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Body Impedance is an effective biometric because each human body
exhibits a unique response to a signal applied at the palm of one hand
and measured in the palm of the other hand. We will see how body
impedance can be used both as a traditional biometric; to generate
cryptographic keys for use in traditional security purposes; or for
device pairing.

Our device pairing scheme is based on the idea that two devices can
pair, if they are physically held by the same person (at the same
time). To pair two devices, a person touches a conductive surface on
each device. While the person is in contact with both devices, the
human body acts as a transmission medium for intra-body communication
and the two devices can communicate through the body. This body
channel is used as part of a pairing protocol which allows the devices
to agree on a mutual secret and, at the same time, extract physical
features to verify that they are being held by the same person. We
prove that our device pairing protocol is secure with respect to a
strong threat model and we build a proof of concept set-up and conduct
experiments with 15 people to verify the idea in practice


Kasper Rasmussen is an Associate Professor in the Computer Science
Department at the University of Oxford. He joined the department in
2013 and in 2015 was awarded a University Research Fellowship from the
Royal Society in London. Prior to being at Oxford, Kasper Rasmussen
spent two years as a post-doc at University of California, Irvine.
Kasper Rasmussen did his Ph.D. with prof. Srdjan Capkun at the
Department of Computer Science at ETH Zurich (Switzerland), where he
worked on security issues relating to secure time synchronization and
secure localization with a particular focus on distance bounding. His
thesis won the “ETH Medal” for an outstanding dissertation from the
Swiss Federal Institute of Technology and he was additionally awarded
the Swiss National Science Foundation (SNSF), Fellowship for
prospective researchers.

CITI Talk: From 5G Towards the Internet of Skills – Mischa Dohler (King’s College London, UK) – 1/12 at 9am, Amphi Chappe

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Abstract: Underpinned by latest developments in ultra-reliable low-latency 5G, we are able to design a fully immersive next-generation internet. This new internet, the “Internet of Skills”, will allow transmitting physical skills digitally. This talk will explore latest developments in 5G as well as the industry and societal applications thereof.

CITI Talk: Spectrum sharing and co-exististence of radar and communication systems – ​​Visa Koivunen (Aalto University, Finland​) – 30/11​ at​ 4pm, Amphi Chappe

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Visa Koivunen, Aalto-yliopisto, Aalto University, School of Electrical Engineering, ELEC, 2011
Abstract: The coexistence of radar and communication has received a lot of attention from the research community in the recent years due to a considerable number of wireless systems that share the same spectral band, e.g.,  LTE, 5G, WiFi and S-band radars. In a plain coexistence scenario, each system tries to mitigate the interference from the other one. In a co-operative scenario, there is some exchange of information between the two systems, for example, channel state or interference awareness. In this talk, waveform optimization methods for target detection and parameter estimation are presented in a co-operative scenario. Mutual Information, and channel and interference awareness are exploited in optimization. Generalized multicarrier waveform model is employed in the radar system. Additional constraints on the waveform properties are imposed. In target parameter estimation, the objective function maximizes the Fischer Information (or minimizes CRB). Simulation examples of optimizing waveforms for target detection and parameter are provided. Time allowing, precoder-decoder design approach employing interference alignment is presented for co-existing radar and communication system.

CITI Talk: Complex Event Processing over Data Streams – Syed Gillani (ATER CITI / TC INSA de Lyon), September 25th at 11am in TD-D

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Complex Event Processing over Data Streams

The concept of event processing is established as a generic computational paradigm in various application fields, ranging from data processing in Web environments, over maritime and transport, to finance and medicine. Events report on state changes of a system and its environment. Complex Event Processing  (CEP) in turn, refers to the identification of complex/composite events of interest, which are collections of simple events that satisfy some pattern, thereby providing the opportunity for reactive and proactive measures. Examples include the recognition of attacks in computer network nodes, human activities on video content, emerging stories and trends on the Social Web, traffic and transport incidents in smart cities, fraud in electronic marketplaces, etc. The goal of this talk is to first provide an overview of this field and second discuss some major challenges that arise due to the high volume and velocity of the generated event streams. In the end I will discuss the building blocks of our recent system to mitigate the inherent issues in CEP.

Syed Gillani is currently an ATER in CITI INSA Lyon. His research interests are in the broad area of database systems, stream processing, query optimisations and Semantic Web. During his PhD he proposed various techniques to bridge the gap between core Semantic Web concepts and database optimisation techniques. Furthermore, he proposed a new query language and its implementation for the Semantic Complex Event Processing.

CITI Talk: “Multi-Agent Simulation and High Performance Computing on Graphics Cards”, Fabien Michel, associate professor HDR (lab. LIRMM, UMR Univ. Montpellier / CNRS)

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Simulation multi-agents et calcul haute performance sur carte


Nombre de systèmes complexes sont aujourd’hui étudiés par simulation
grâce à des modèles basés sur le paradigme multi-agents. Dans ces
modèles, les individus, leur environnement  et leurs interactions sont
directement représentés. Ce type de simulation nécessite parfois de
considérer un grand nombre d’entités, ce qui pose des problèmes de
performance et de passage à l’échelle. Dans ce  cadre, la programmation
sur carte graphique  (GPGPU) est une solution attrayante : elle permet
des gains de performances très conséquents sur des ordinateurs
personnels. Le GPGPU nécessite cependant une programmation extrêmement
spécifique qui limite à la fois son accessibilité et la réutilisation
des développements réalisés, ce qui est particulièrement vrai dans le
contexte de la simulation multi-agents. Dans cet exposé, nous
présenterons cette technologie et les travaux de recherche que nous
avons réalisés afin de pallier ces difficultés. Nous décrirons en
particulier une méthode de conception, appelée délégation GPU, qui
permet (1) d’adapter les modèles multi-agents au contexte du GPGPU et de
(2) faciliter la réutilisation des développements associés.


Fabien Michel est titulaire d’un doctorat en informatique obtenu à
l’Université de Montpellier en 2004. De 2005 à 2008, il a exercé en tant
que maître de conférences au CReSTIC de Reims avant de rejoindre le
Laboratoire d’Informatique, de Robotique et de Microélectronique de
Montpellier (LIRMM) où il exerce actuellement. Ses recherches
s’inscrivent principalement dans le domaine de la modélisation et de la
simulation de systèmes multi-agents (SMA) et reposent sur la proposition
de modèles formels et conceptuels (e.g. le modèle IRM4S) et d’outils
logiciels génériques (plates-formes MaDKit et TurtleKit), ainsi que sur
leur utilisation dans divers domaines tels que le jeu vidéo, le
traitement numérique de l’image ou la robotique collective. Plus
spécifiquement, le fil rouge de ses travaux, synthétisé dans son HDR
obtenue en 2015, repose sur une approche dite
« environement-centrée » (E4MAS) : contrairement aux approches centrées
sur la conception des comportements individuels, il s’agit de considérer
l’environnement des agents comme une abstraction de premier ordre dont
le rôle est primodial. En particulier, il a récemment décliné cette
démarche afin de proposer une approche originale dans le cadre de
l’utilisation du calcul haute performance sur carte graphique (GPGPU)
pour la simulation de SMA.

CITI Talk: “New achievable rate regions for fundamental network information theory problems”, Arun Padakandla (Purdue University, IN, USA), 17/07 14h

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New achievable rate regions for fundamental network information theory problems
Arun Padakandla (Purdue University, IN, USA)
In this talk, we consider the fundamental information-theoretic problems of characterizing 2) the capacity regions of channel coding problems such as broadcast, interference and 2) necessary and sufficient conditions for joint source-channel coding of distributed correlated sources. Going beyond independent and identically distributed codewords, we propose the ensemble of coset codes possessing algebraic closure properties and derive new achievable rate regions (inner bounds) to the capacity regions of the former problems with three or more receivers. Our findings are based on characterizing performance of new encoding and decoding rules that exploit the algebraic properties of these codes. Next, we observe that the conventional approach of single-letter coding is sub-optimal for joint source channel coding over multiple access and interference channels. We propose a novel multi-letter coding technique based on appropriately stitching together single-letter techniques. Most importantly, we characterize an inner bound to its performance via a single-letter expression, which is proven to strictly enlarges currently known single-letter achievable rate regions based on single-letter coding. This puts forth a useful technique for characterizing new inner bounds to problems that might not permit an optimal single-letter technique.