16,360 research outputs found
Capsule Routing for Sound Event Detection
The detection of acoustic scenes is a challenging problem in which
environmental sound events must be detected from a given audio signal. This
includes classifying the events as well as estimating their onset and offset
times. We approach this problem with a neural network architecture that uses
the recently-proposed capsule routing mechanism. A capsule is a group of
activation units representing a set of properties for an entity of interest,
and the purpose of routing is to identify part-whole relationships between
capsules. That is, a capsule in one layer is assumed to belong to a capsule in
the layer above in terms of the entity being represented. Using capsule
routing, we wish to train a network that can learn global coherence implicitly,
thereby improving generalization performance. Our proposed method is evaluated
on Task 4 of the DCASE 2017 challenge. Results show that classification
performance is state-of-the-art, achieving an F-score of 58.6%. In addition,
overfitting is reduced considerably compared to other architectures.Comment: Paper accepted for 26th European Signal Processing Conference
(EUSIPCO 2018
The edge-disjoint path problem on random graphs by message-passing
We present a message-passing algorithm to solve the edge disjoint path
problem (EDP) on graphs incorporating under a unique framework both traffic
optimization and path length minimization. The min-sum equations for this
problem present an exponential computational cost in the number of paths. To
overcome this obstacle we propose an efficient implementation by mapping the
equations onto a weighted combinatorial matching problem over an auxiliary
graph. We perform extensive numerical simulations on random graphs of various
types to test the performance both in terms of path length minimization and
maximization of the number of accommodated paths. In addition, we test the
performance on benchmark instances on various graphs by comparison with
state-of-the-art algorithms and results found in the literature. Our
message-passing algorithm always outperforms the others in terms of the number
of accommodated paths when considering non trivial instances (otherwise it
gives the same trivial results). Remarkably, the largest improvement in
performance with respect to the other methods employed is found in the case of
benchmarks with meshes, where the validity hypothesis behind message-passing is
expected to worsen. In these cases, even though the exact message-passing
equations do not converge, by introducing a reinforcement parameter to force
convergence towards a sub optimal solution, we were able to always outperform
the other algorithms with a peak of 27% performance improvement in terms of
accommodated paths. On random graphs, we numerically observe two separated
regimes: one in which all paths can be accommodated and one in which this is
not possible. We also investigate the behaviour of both the number of paths to
be accommodated and their minimum total length.Comment: 14 pages, 8 figure
Chinese Internet AS-level Topology
We present the first complete measurement of the Chinese Internet topology at
the autonomous systems (AS) level based on traceroute data probed from servers
of major ISPs in mainland China. We show that both the Chinese Internet AS
graph and the global Internet AS graph can be accurately reproduced by the
Positive-Feedback Preference (PFP) model with the same parameters. This result
suggests that the Chinese Internet preserves well the topological
characteristics of the global Internet. This is the first demonstration of the
Internet's topological fractality, or self-similarity, performed at the level
of topology evolution modeling.Comment: This paper is a preprint of a paper submitted to IEE Proceedings on
Communications and is subject to Institution of Engineering and Technology
Copyright. If accepted, the copy of record will be available at IET Digital
Librar
Characterizing a Meta-CDN
CDNs have reshaped the Internet architecture at large. They operate
(globally) distributed networks of servers to reduce latencies as well as to
increase availability for content and to handle large traffic bursts.
Traditionally, content providers were mostly limited to a single CDN operator.
However, in recent years, more and more content providers employ multiple CDNs
to serve the same content and provide the same services. Thus, switching
between CDNs, which can be beneficial to reduce costs or to select CDNs by
optimal performance in different geographic regions or to overcome CDN-specific
outages, becomes an important task. Services that tackle this task emerged,
also known as CDN broker, Multi-CDN selectors, or Meta-CDNs. Despite their
existence, little is known about Meta-CDN operation in the wild. In this paper,
we thus shed light on this topic by dissecting a major Meta-CDN. Our analysis
provides insights into its infrastructure, its operation in practice, and its
usage by Internet sites. We leverage PlanetLab and Ripe Atlas as distributed
infrastructures to study how a Meta-CDN impacts the web latency
Local Search in Unstructured Networks
We review a number of message-passing algorithms that can be used to search
through power-law networks. Most of these algorithms are meant to be
improvements for peer-to-peer file sharing systems, and some may also shed some
light on how unstructured social networks with certain topologies might
function relatively efficiently with local information. Like the networks that
they are designed for, these algorithms are completely decentralized, and they
exploit the power-law link distribution in the node degree. We demonstrate that
some of these search algorithms can work well on real Gnutella networks, scale
sub-linearly with the number of nodes, and may help reduce the network search
traffic that tends to cripple such networks.Comment: v2 includes minor revisions: corrections to Fig. 8's caption and
references. 23 pages, 10 figures, a review of local search strategies in
unstructured networks, a contribution to `Handbook of Graphs and Networks:
From the Genome to the Internet', eds. S. Bornholdt and H.G. Schuster
(Wiley-VCH, Berlin, 2002), to be publishe
An Internet Heartbeat
Obtaining sound inferences over remote networks via active or passive
measurements is difficult. Active measurement campaigns face challenges of
load, coverage, and visibility. Passive measurements require a privileged
vantage point. Even networks under our own control too often remain poorly
understood and hard to diagnose. As a step toward the democratization of
Internet measurement, we consider the inferential power possible were the
network to include a constant and predictable stream of dedicated lightweight
measurement traffic. We posit an Internet "heartbeat," which nodes periodically
send to random destinations, and show how aggregating heartbeats facilitates
introspection into parts of the network that are today generally obtuse. We
explore the design space of an Internet heartbeat, potential use cases,
incentives, and paths to deployment
Mediator-assisted multi-source routing in information-centric networks
Among the new communication paradigms recently proposed, information-centric networking (ICN) is able to natively support content awareness at the network layer shifting the focus from hosts (as in traditional IP networks) to information objects. In this paper, we exploit the intrinsic content-awareness ICN features to design a novel multi-source routing mechanism. It involves a new network entity, the ICN mediator, responsible for locating and delivering the requested information objects that are chunked and stored at different locations. Our approach imposes very limited signalling overhead, especially for large chunk size (MBytes). Simulations show significant latency reduction compared to traditional routing approaches
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