4 research outputs found
Distributed privacy-preserving network size computation: A system-identification based method
In this study, we propose an algorithm for computing the network size of
communicating agents. The algorithm is distributed: a) it does not require a
leader selection; b) it only requires local exchange of information, and; c)
its design can be implemented using local information only, without any global
information about the network. It is privacy-preserving, namely it does not
require to propagate identifying labels. This algorithm is based on system
identification, and more precisely on the identification of the order of a
suitably-constructed discrete-time linear time-invariant system over some
finite field. We provide a probabilistic guarantee for any randomly picked node
to correctly compute the number of nodes in the network. Moreover, numerical
implementation has been taken into account to make the algorithm applicable to
networks of hundreds of nodes, and therefore make the algorithm applicable in
real-world sensor or robotic networks. We finally illustrate our results in
simulation and conclude the paper with discussions on how our technique differs
from a previously-known strategy based on statistical inference.Comment: 52nd IEEE Conference on Decision and Control (CDC 2013) (2013
Learning-Based Distributed Detection-Estimation in Sensor Networks with Unknown Sensor Defects
We consider the problem of distributed estimation of an unknown deterministic
scalar parameter (the target signal) in a wireless sensor network (WSN), where
each sensor receives a single snapshot of the field. We assume that the
observation at each node randomly falls into one of two modes: a valid or an
invalid observation mode. Specifically, mode one corresponds to the desired
signal plus noise observation mode (\emph{valid}), and mode two corresponds to
the pure noise mode (\emph{invalid}) due to node defect or damage. With no
prior information on such local sensing modes, we introduce a learning-based
distributed procedure, called the mixed detection-estimation (MDE) algorithm,
based on iterative closed-loop interactions between mode learning (detection)
and target estimation. The online learning step re-assesses the validity of the
local observations at each iteration, thus refining the ongoing estimation
update process. The convergence of the MDE algorithm is established
analytically. Asymptotic analysis shows that, in the high signal-to-noise ratio
(SNR) regime, the MDE estimation error converges to that of an ideal
(centralized) estimator with perfect information about the node sensing modes.
This is in contrast to the estimation performance of a naive average consensus
based distributed estimator (without mode learning), whose estimation error
blows up with an increasing SNR.Comment: 15 pages, 2 figures, submitted to TS
Distributed statistical estimation of the number of nodes in Sensor Networks
Abstract — The distributed estimation of the number of active sensors in a network can be important for estimation and organization purposes. We propose a design methodology based on the following paradigm: some locally randomly generated values are exchanged among the various sensors and thus mod-ified by known consensus-based strategies. Statistical analysis of the a-consensus values allows estimation of the number of participant sensors. The main features of this approach are: algorithms are completely distributed, since they do not require leader election steps; sensors are not requested to transmit authenticative information (for example identificative numbers or similar data), and thus the strategy can be implemented whenever privacy problems arise. After a rigorous formulation of the paradigma we analyze some practical examples, fully characterize them from a statistical point of view, and finally we provide some general theoretical results and asymptotic analyses. Index Terms — sensor networks, distributed estimation, num-ber of sensors, consensus algorithms I