arXiv subjects

Yvonne-Anne Pignolet

Publications and source records attributed to Yvonne-Anne Pignolet.

23 records · Page 2Linked to original sources

arXiv2015

Simultaneous Acoustic Localization of Multiple Smartphones with Euclidean Distance Matrices

In this paper, we present an acoustic localization system for multiple devices. In contrast to systems which localise a device relative to one or several anchor points, we focus on the joint localisation of several devices relative to each other. We present a prototype of our system on off-the-shelf smartphones. No user interaction is required, the phones emit acoustic pulses according to a precomputed schedule. Using the elapsed time between two times of arrivals (ETOA) method with sample counting, distances between the devices are estimated. These, possibly incomplete, distances are the input to an efficient and robust multi-dimensional scaling algorithm returning a position for each phone. We evaluated our system in real-world scenarios, achieving error margins of 15 cm in an office environment.

cs.NI↗

arXiv2013

Request Complexity of VNet Topology Extraction: Dictionary-Based Attacks

The network virtualization paradigm envisions an Internet where arbitrary virtual networks (VNets) can be specified and embedded over a shared substrate (e.g., the physical infrastructure). As VNets can be requested at short notice and for a desired time period only, the paradigm enables a flexible service deployment and an efficient resource utilization. This paper investigates the security implications of such an architecture. We consider a simple model where an attacker seeks to extract secret information about the substrate topology, by issuing repeated VNet embedding requests. We present a general framework that exploits basic properties of the VNet embedding relation to infer the entire topology. Our framework is based on a graph motif dictionary applicable for various graph classes. Moreover, we provide upper bounds on the request complexity, the number of requests needed by the attacker to succeed.

cs.NI↗

arXiv2012

From Caesar to Twitter: An Axiomatic Approach to Elites of Social Networks

In many societies there is an elite, a relatively small group of powerful individuals that is well-connected and highly influential. Since the ancient days of Julius Caesar's senate of Rome to the recent days of celebrities on Twitter, the size of the elite is a result of conflicting social forces competing to increase or decrease it. The main contribution of this paper is the answer to the question how large the elite is at equilibrium. We take an axiomatic approach to solve this: assuming that an elite exists and it is influential, stable and either minimal or dense, we prove that its size must be $Θ(\sqrt{m})$ (where $m$ is the number of edges in the network). As an approximation for the elite, we then present an empirical study on nine large real-world networks of the subgraph formed by the highest degree nodes, also known as the rich-club. Our findings indicate that elite properties such as disproportionate influence, stability and density of $Θ(\sqrt{m})$-rich-clubs are universal properties and should join a growing list of common phenomena shared by social networks and complex systems such as "small world," power law degree distributions, high clustering, etc.

cs.SI↗

arXiv2012

Multi-Interface PLC / Wireless Network Simulation

Many communication networks consist of legacy and new devices using heterogeneous technologies, such as copper wire, optical fiber, wireless and power line communication (PLC). Most network simulators, however, have been designed to work well with a single underlying link layer technology. Furthermore, there are hardly any suitable models for network simulators of PLC. In this paper we present extensions of the Contiki OS network simulator Cooja: A device may support multiple interfaces accessing multiple PLC segments or wireless channels and a simple PLC medium model is introduced describing packet loss probability as a function of distance. We test our approach to simulate a Smart Grid scenario of Ring Main Units equipped with PLC devices.

cs.NI↗

arXiv2010

A note on uniform power connectivity in the SINR model

In this paper we study the connectivity problem for wireless networks under the Signal to Interference plus Noise Ratio (SINR) model. Given a set of radio transmitters distributed in some area, we seek to build a directed strongly connected communication graph, and compute an edge coloring of this graph such that the transmitter-receiver pairs in each color class can communicate simultaneously. Depending on the interference model, more or less colors, corresponding to the number of frequencies or time slots, are necessary. We consider the SINR model that compares the received power of a signal at a receiver to the sum of the strength of other signals plus ambient noise . The strength of a signal is assumed to fade polynomially with the distance from the sender, depending on the so-called path-loss exponent $α$. We show that, when all transmitters use the same power, the number of colors needed is constant in one-dimensional grids if $α>1$ as well as in two-dimensional grids if $α>2$. For smaller path-loss exponents and two-dimensional grids we prove upper and lower bounds in the order of $\mathcal{O}(\log n)$ and $Ω(\log n/\log\log n)$ for $α=2$ and $Θ(n^{2/α-1})$ for $α<2$ respectively. If nodes are distributed uniformly at random on the interval $[0,1]$, a \emph{regular} coloring of $\mathcal{O}(\log n)$ colors guarantees connectivity, while $Ω(\log \log n)$ colors are required for any coloring.

cs.DM↗