## About

302

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13,994

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Citations since 2016

Introduction

Additional affiliations

December 2011 - March 2015

## Publications

Publications (302)

This paper investigates moving networks of Unmanned Aerial Vehicles to extend connectivity and guarantee data rates in the 5G by analysing possible hovering locations based on limitations such as flight time and coverage. The authors provide analytic bounds on the requirements in terms of connectivity extension for vehicular networks served by fixe...

We present low complexity and efficient path selection algorithms for limiting the exposure to pandemic virus during and between lock-downs. The average outdoor exposure rate reduction is around 3.

This paper investigates moving networks of Unmanned Aerial Vehicles (UAVs), such as drones, as one of the innovative opportunities brought by the 5G. With a main purpose to extend connectivity and guarantee data rates, the drones require hovering locations due to limitations such as flight time and coverage surface. We provide analytic bounds on th...

We characterize trade-offs between the end-to-end communication delay and the energy in urban vehicular communications with infrastructure assistance. Our study exploits the self-similarity of the location of communication entities in cities by modeling them with an innovative model called "hyperfractal". We show that the hyperfractal model can be...

String complexity is defined as the cardinality of a set of all distinct words (factors) of a given string. For two strings, we introduce the joint string complexity as the cardinality of a set of words that are common to both strings. String complexity finds a number of applications from capturing the richness of a language to finding similarities...

In [1] we have presented the Ariadne String against Covid application, whose aim was to recommend safe outdoor path inside cities in order to limit the exposure to virus propagation during aimless outdoor leisure excursion. The main idea was to make a load balancing between streets via space-time diversity via a random walk. The application was sho...

We present the Ariadne String against Covid application , whose aim is to recommend safe outdoor path inside cities in order to limit the exposure to virus propagation. The main idea is to make a load balancing between streets via space-time diversity. The application is shown to be efficient at the very first user, and lead to an optimal Nash equi...

While cryptocurrencies and blockchain applications continue to gain popularity, their energy cost is evidently becoming unsustainable. In most instances, the main cost comes from the required amount of energy for the Proof-of-Work, and this cost is inherent to the design. In addition, useless costs from discarded work (e.g., the so-called Forks) an...

This paper studies the fundamental communication properties of urban vehicle networks by exploiting the selfsimilarity and hierarchical organization of modern cities. We use an innovative model called “hyperfractal” that captures the selfsimilarities of both the traffic and vehicle locations but avoids the extremes of regularity and randomness. We...

We present results on the trade-offs between the end-to-end communication delay and the energy spent in millimeter wave vehicular communications in urban settings. This study exploits the self-similarities of the traffic and vehicle locations in cities captured in our innovative model called "hyperfractal''. We enrich the model by incorporating roa...

Our contribution consists in deriving an adaptive multiplicity code based PIR protocol based on a code selection algorithm which guarantees minimal communication overhead for a given system architecture. We formulate the related constrained optimization problem, analyze it and introduce an algorithm for enabling the adaptive Information Theoretical...

String complexity is defined as the cardinality of a set of all distinct words (factors) of a given string. For two strings, we introduce the joint string complexity as the cardinality of a set of words that are common to both strings. String complexity finds a number of applications from capturing the richness of a language to finding similarities...

While cryptocurrencies continue to gain popularity, their energy cost is increasingly becoming unsustainable. In this paper, we present an innovative scheme which eliminates the burden of the proof of work which is the main cause of the energy waste in cryptocurrencies such as Bitcoin. The scheme is based on a green leader election scheme which gua...

The goal of this paper is to increase our understanding of the fundamental performance limits of urban vehicle networks by exploiting the self-similarity and hierarchical organization of modern cities. We use an innovative model called "hyperfractal" that captures the self-similarity of the topology and vehicle locations while avoiding the extremes...

In this work we study a Poisson patterns of fixed and mobile nodes distributed on straight lines designed for 2D urban wireless networks. The particularity of the model is that, in addition to capturing the irregularity and variability of the network topology, it exploits self-similarity, a characteristic of urban wireless networks. The pattern obe...

Because of the significant increase in size and complexity of the networks, the distributed computation of eigenvalues and eigenvectors of graph matrices has become very challenging and yet it remains as important as before. In this paper we develop efficient distributed algorithms to detect, with higher resolution, closely situated eigenvalues and...

Mankind has never been connected as it is now and as it will be tomorrow. Nowadays thanks to the rise of social networks such as Tweeter and Facebook, we can follow in real time the thought of millions of people. In fact we can almost feel the thoughts of a whole humanity and maybe project ourselves in a position where we could predict the major tr...

Mankind has never been connected as it is now and as it will be tomorrow. Nowadays thanks to the rise of social networks such as Tweeter and Facebook, we can follow in real time the thought of millions of people. In fact we can almost feel the thoughts of a whole humanity and maybe project ourselves in a position where we could predict the major tr...

We study a suffix tree built from a sequence generated by a Markovian source. Such sources are more realistic probabilistic models for text generation, data compression, molecular applications, and so forth. We prove that the average size of such a suffix tree is asymptotically equivalent to the average size of a trie built over $n$ independent seq...

In this paper we introduce a novel information propagation method in Twitter, while maintaining a low computational complexity. It exploits the power of Compressive Sensing in conjunction with a Kalman filter to update the states of a dynamical system. The proposed method first employs Joint Complexity, which is defined as the cardinality of a set...

How do you distinguish a cat from a dog by their DNA? Did Shakespeare really write all of his plays? Pattern matching techniques can offer answers to these questions and to many others, from molecular biology, to telecommunications, to classifying Twitter content. This book for researchers and graduate students demonstrates the probabilistic approa...

We study the Lempel-Ziv'78 algorithm and show that its (normalized) redundancy rate tends to a Gaussian distribution for memoryless sources. We accomplish it by extending findings from our 1995 paper, in particular, by presenting a new simplified proof of the central limit theorem (CLT) for the number of phrases in the LZ'78 algorithm. We first ana...

We resolve a conjecture proposed by D.E. Knuth concerning a recurrence arising in the satisfiability problem. Knuth’s recurrence resembles recurrences arising in the analysis of tries, in particular PATRICIA tries, and asymmetric leader election. We solve Knuth’s recurrence exactly and asymptotically, using analytic techniques such as the Mellin tr...

In this paper we introduce a novel method to perform topic detection in Twitter based on the recent and novel technique of Joint Complexity. Instead of relying on words as most other existing methods which use bag-of-words or n-gram techniques, Joint Complexity relies on String Complexity which is defined as the cardinality of a set of all distinct...

In this paper we present an efficient encryption system based on Compressive Sensing, without the additional computational cost of a separate encryption protocol, when applied to indoor location estimation problems. The breakthrough of the method is the use of the weakly encrypted measurement matrices which are generated when solving the optimizati...

The Optimized Link State Routing Protocol version 2 (OLSRv2) includes
the ability to assign metrics to links and to use those metrics to
allow routing by other than minimum hop count routes. This document
provides a historic record of the rationale for, and design
considerations behind, how link metrics were included in OLSRv2.

This specification describes version 2 of the Optimized Link State Routing Protocol (OLSRv2) for Mobile Ad Hoc Networks (MANETs).

In this paper we study joint sequence complexity and its applications for finding similarities between sequences up to the discrimination of sources. The mathematical concept of the complexity of a sequence is defined as the number of distinct subsequences of it. Sequences containing many common parts have a higher joint complexity. The analysis of...

Telecommunication networks deliver a massive volume of data to individuals and institutions day after day. Network operations also generate valuable data about the network's own health and status. Similarly, records of the activities they support convey much about the subscribers and devices they serve. In each context, there are opportunities to d...

In this paper, a hybrid path-tracking system is introduced, which exploits the power of compressive sensing (CS) to recover accurately sparse signals, in conjunction with the efficiency of a Kalman filter to update the states of a dynamical system. The proposed method first employs a hierarchical region-based approach to constrain the area of inter...

We want to estimate the average capacity of MISO networks when several simultaneous emitters and a single access point are randomly distributed in an infinite fractal map embedded in a space of dimension D. We first show that the average capacity is a constant when the nodes are uniformly distributed in the space. This constant is function of the s...

We introduce a new algorithm to achieve a distributed leader election in a broadcast channel that is more efficient than the classic Part-and-Try algorithm. The algorithm has the advantage of having a reduced overhead log logN rather than logN. More importantly, the algorithm has a greatly reduced energy consumption since it requires O(N1=k) burst...

We study the information propagation speed in multi-lane vehicle-to-vehicle networks such as roads or highways. We focus on the impact of time-varying radio ranges and of multiple lanes of vehicles, varying in speed and in density. We assess the existence of a vehicle density threshold under which information propagates on average at the fastest ve...

We propose a classification test to discriminate Markov sources based on the joint string complexity. String complexity is defined as the cardinality of a set of all distinct words (factors) of a given string. For two strings, we define the joint string complexity as the cardinality of the set of words which both strings have in common. In this pap...

We show that the cumulated emitter individual capacities toward an access point is in average equal to a simple constant when the emitters are randomly distributed in an infinite space. This constant depends on the space dimension and on the signal attenuation factor, it holds even in presence of fading effects. We also extend this formula when the...

In this paper we present a new approach for cognitive radio. In the usual approach the secondary network is in charge of monitoring the channel to determine whether or not the primary network is active in the area. If it is not, the secondary network is allowed to use the spectrum. In the new access scheme we propose, the primary network encompasse...

The method of types is one of the most popular techniques in information theory and combinatorics. Two sequences of equal length have the same type if they have identical empirical distributions. In this paper, we focus on Markov types, that is, sequences generated by a Markov source (of order one). We note that sequences having the same Markov typ...

In this paper, we apply the ideas of the matrix column based diffusion
approach to define a new eigenvector computation algorithm of a stationary
probability of a Markov chain.

We study the problem of geometric optimization of medium access control in
multi-hop wireless network. We discuss the optimal placements of simultaneous
transmitters in the network and our general framework allows us to evaluate the
performance gains of highly managed medium access control schemes that would be
required to implement these placement...

Jitter is used in wireless ad hoc networks to reduce the number of packet collisions and the number of transmissions. This is done by scheduling random back-off for each packet to be transmitted and by piggybacking multiple packets in a single transmission. This technique has been standardized by the IETF in RFC 5148. This paper investigates on the...

In this paper, we provide a full analysis of the information propagation speed in bidirectional vehicular delay tolerant networks such as roads or highways. The provided analysis shows that a phase transition occurs concerning the information propagation speed, with respect to the vehicle densities in each direction of the highway. We prove that un...

This article introduces a metric for performance evaluation of medium access
schemes in wireless ad hoc networks known as local capacity. Although deriving
the end-to-end capacity of wireless ad hoc networks is a difficult problem, the
local capacity framework allows us to quantify the average information rate
received by a receiver node randomly l...

International audience
String complexity is defined as the cardinality of a set of all distinct words (factors) of a given string. For two strings, we define $\textit{joint string complexity}$ as the set of words that are common to both strings. We also relax this definition and introduce $\textit{joint semi-complexity}$ restricted to the common wo...

We quantify the throughput capacity of wireless multi-hop networks with
several medium access schemes. We analyze pure ALOHA scheme where simultaneous
transmitters are dispatched according to a uniform Poisson distribution and
exclusion schemes where simultaneous transmitters are dispatched according to
an exclusion rule such as node coloring and c...

We study the optimal transmission scheme that maximizes the local capacity in
two-dimensional (2D) wireless networks. Local capacity is defined as the
average information rate received by a node randomly located in the network.
Using analysis based on analytical and numerical methods, we show that maximum
local capacity can be obtained if simultane...

In this work, we evaluate local capacity of wireless ad hoc networks with
several medium access protocols and identify the most optimal protocol. We
define local capacity as the average information rate received by a receiver
randomly located in the network. We analyzed grid pattern protocols where
simultaneous transmitters are positioned in a regu...

In this paper we use measurements captured from real Wifi devices, to analyze their statistical properties specifically, we investigate the time dependent noise affecting the received signal strengths, the stationary aspect of the RSS statistics (mean received signal strength) when we stay motionless. Then we explore the time independent noise whic...

We show that the Lempel Ziv'78 redundancy rate tends to a Gaussian distribution for memoryless sources. We accomplish it by extending findings from our 1995 paper [3]. We present a new simplified proof of the Central Limit Theorem for the number of phrases in the LZ'78 algorithm. As in our 1995 paper, here we first analyze the asymptotic behavior o...

Accurate indoor localization is a significant task for many ubiq-uitous and pervasive computing applications, with numerous solu-tions based on IEEE802.11, bluetooth, ultrasound and infrared tech-nologies being proposed. The inherent sparsity present in the prob-lem of location estimation motivates in a natural fashion the use of the recently intro...

We study the scaling properties of a georouting scheme in a wireless
multi-hop network of $n$ mobile nodes. Our aim is to increase the network
capacity quasi linearly with $n$ while keeping the average delay bounded. In
our model, mobile nodes move according to an i.i.d. random walk with velocity
$v$ and transmit packets to randomly chosen destinat...

Jitter is used in wireless ad hoc networks to reduce the number of packet collisions and the number of transmissions. This is done by scheduling random back-off for each packet to be transmitted and by piggybacking multiple packets in a single transmission. This technique has been standardized by the IETF in RFC 5148. This paper investigates on the...

We propose a new indoor tracking method which can be used on mobile nodes. Our method uses only the received signal strengths as input information and does not require a cinematic motion model to track the mobile node. We discuss in detail the features of our approach and its resulting algorithm. We evaluate the performances of our algorithm using...

In this paper, a hybrid path tracking system is presented, which exploits the efficiency of a Kalman filter in conjunction with the power of compressive sensing to represent accurately sparse signals and a region-based multivariate Gaussian model. The experimental evaluation reveals an increased localization performance, while maintaining a low com...

In this paper, we provide an analysis of the information propagation speed in bidirectional vehicular delay tolerant networks on highways. We show that a phase transition occurs concerning the information propagation speed, with respect to the vehicle densities in each direction of the highway. We prove that under a certain threshold, information p...

Protocols that are to be employed in the context of the Internet of Things (IoT) have to meet a wide variety of application-specific requirements. In this report, we reflect on recent experiences, gained from several real-world deployments in which we have participated, which use low power, embedded networking devices. We discuss the lessons learne...

We give an estimate of an upper bound of information propagation speed as a function of a targeted transport capacity density. The propagation speed depends on the density of simultaneous emitters and the node mobility model. We assume that nodes move according to an independent random walk. This work makes the junction between the work of Gupta an...

This chapter explores techniques that enable efficient link state routing on compound networks. These techniques rely on the selection and maintenance of a subset of links in the network (i.e. an overlay) along which the different operations of link-state routing can be performed more efficiently. This chapter provides a formal analysis of such tec...

In practice, ad hoc networks are still too unreliable for standard mobile and vehicular communications. It is thus important to complement current protocols in this context, with schemes guaranteeing the exchange of critical data when needed. A promising approach in this realm is to use an overlay subgraph, over which critical messages are exchange...

We study the classical problem of noisy constrained capacity in the case of the binary symmetric channel (BSC), namely, the capacity of a BSC whose input is a sequence from a constrained set. As stated by Fan , “... while calculation of the noise-free capacity of constrained sequences is well known, the computation of the capacity of a constraint i...

The goal of this paper is to increase our understanding of the fundamental performance limits of mobile and Delay Tolerant Networks (DTNs), where end-to-end multihop paths may not exist and communication routes may only be available through time and mobility. We use analytical tools to derive generic theoretical upper bounds for the information pro...

Vehicular Ad hoc NETworks (VANETs) aim at increasing safety on our road networks as well as bringing road users new applications and entertainment. Ad hoc networks with a linear topology appear frequently in VANETs stimulating increased interest in the study of linear ad hoc networks. Access in VANETs is usually governed by Carrier Sense Multiple A...

Efficient OSPF (Open Shortest Path First) operation on multi-hop ad hoc wireless networks has becomedesirable, as wireless community mesh networks and vehicular networks emerge using OLSR (OptimizedLink State Routing), a link state MANET routing protocol similar to OSPF in many aspects. OSPF isalready extensively deployed and well known in wired IP...

Achieving reliable communication of critical data on mobile ad hoc networks is a must before MANETs can be considered practical for standard mobile and vehicular communications. This paper thus focuses on schemes that complement existing ad hoc broadcast mechanisms (inherently unreliable), which can guarantee the full diffusion of critical messages...

We present our analysis and results that allow us to conjecture that maximum capacity in wireless networks can be achieved if nodes transmitting simultaneously are positioned in a hexagonal grid pattern. But obviously, it is very difficult to realize such a protocol which ensures that active transmitters in the network are positioned in any specifi...

We propose a new indoor localization method which can be used to track a mobile node . Our method uses only the received signal strengths as input information . In addition our approach doesn't require any prior knowledge of the mobile node's motion and therefore doesn't use a cinematic motion model for tracking the mobile node. We discuss in detai...

We give a new analysis and proof of the Normal limiting distribution of the number of phrases in the 1978 Lempel-Ziv compression algorithm on random sequences built from a memoriless source. This work is a follow-up of our last paper on this subject in 1995. The analysis stands on the asymptotic behavior of a DST obtained by the insertion of random...

We investigate the fundamental capacity limits of space-time journeys of information in mobile and Delay Tolerant Networks (DTNs), where information is either transmitted or carried by mobile nodes, using store-carry-forward routing. We define the capacity of a journey (i.e., a path in space and time, from a source to a destination) as the maximum...

International audience
The method of types is one of the most popular techniques in information theory and combinatorics. Two sequences of equal length have the same type if they have identical empirical distributions. In this paper, we focus on Markov types, that is, sequences generated by a Markov source (of order one). We note that sequences hav...

The need of a flexible radio interface Architecture has been identified as a mean of facilitating migration to the next coming Mobile Ad Hoc Wideband Waveform and the integration of new waveform technologies. Future Ad Hoc networks will link together different elements on the battlefield (vehicles, foot soldiers, helicopters, etc.) and possibly con...

International audience
We analyse the average number of buckets in a Linear Bucket tree created by $n$ points uniformly dispatched on an interval of length $y$. A new bucket is created when a point does not fall in an existing bucket. The bucket is the interval of length 2 centered on the point. We illustrate this concept by an interesting tale of...

International audience
Motivated by the recent refutation of information loss paradox in black hole by Hawking, we investigate the new concept of {\it non unitary random walks}. In a non unitary random walk, we consider that the state 0, called the {\it black hole}, has a probability weight that decays exponentially in $e^{-\lambda t}$ for some $\l...

We investigate the fundamental capacity limits of space-time journeys of information in mobile and Delay Tolerant Networks (DTNs), where information is either transmitted or carried by mobile nodes, using store-carry-forward routing. We define the capacity of a journey (i.e., a path in space and time, from a source to a destination) as the maximum...

The method of types is one of the most popular techniques in information theory and combinatorics. Two sequences of equal length have the same type if they have identical empirical distributions. In this paper, we focus on Markov types, that is, sequences generated by a Markov source (of order one). We note that sequences having the same Markov typ...