33,777 research outputs found
Jointly Optimal Routing and Caching for Arbitrary Network Topologies
We study a problem of fundamental importance to ICNs, namely, minimizing
routing costs by jointly optimizing caching and routing decisions over an
arbitrary network topology. We consider both source routing and hop-by-hop
routing settings. The respective offline problems are NP-hard. Nevertheless, we
show that there exist polynomial time approximation algorithms producing
solutions within a constant approximation from the optimal. We also produce
distributed, adaptive algorithms with the same approximation guarantees. We
simulate our adaptive algorithms over a broad array of different topologies.
Our algorithms reduce routing costs by several orders of magnitude compared to
prior art, including algorithms optimizing caching under fixed routing.Comment: This is the extended version of the paper "Jointly Optimal Routing
and Caching for Arbitrary Network Topologies", appearing in the 4th ACM
Conference on Information-Centric Networking (ICN 2017), Berlin, Sep. 26-28,
201
Information Recovery In Behavioral Networks
In the context of agent based modeling and network theory, we focus on the
problem of recovering behavior-related choice information from
origin-destination type data, a topic also known under the name of network
tomography. As a basis for predicting agents' choices we emphasize the
connection between adaptive intelligent behavior, causal entropy maximization
and self-organized behavior in an open dynamic system. We cast this problem in
the form of binary and weighted networks and suggest information theoretic
entropy-driven methods to recover estimates of the unknown behavioral flow
parameters. Our objective is to recover the unknown behavioral values across
the ensemble analytically, without explicitly sampling the configuration space.
In order to do so, we consider the Cressie-Read family of entropic functionals,
enlarging the set of estimators commonly employed to make optimal use of the
available information. More specifically, we explicitly work out two cases of
particular interest: Shannon functional and the likelihood functional. We then
employ them for the analysis of both univariate and bivariate data sets,
comparing their accuracy in reproducing the observed trends.Comment: 14 pages, 6 figures, 4 table
Transfer Learning for Improving Model Predictions in Highly Configurable Software
Modern software systems are built to be used in dynamic environments using
configuration capabilities to adapt to changes and external uncertainties. In a
self-adaptation context, we are often interested in reasoning about the
performance of the systems under different configurations. Usually, we learn a
black-box model based on real measurements to predict the performance of the
system given a specific configuration. However, as modern systems become more
complex, there are many configuration parameters that may interact and we end
up learning an exponentially large configuration space. Naturally, this does
not scale when relying on real measurements in the actual changing environment.
We propose a different solution: Instead of taking the measurements from the
real system, we learn the model using samples from other sources, such as
simulators that approximate performance of the real system at low cost. We
define a cost model that transform the traditional view of model learning into
a multi-objective problem that not only takes into account model accuracy but
also measurements effort as well. We evaluate our cost-aware transfer learning
solution using real-world configurable software including (i) a robotic system,
(ii) 3 different stream processing applications, and (iii) a NoSQL database
system. The experimental results demonstrate that our approach can achieve (a)
a high prediction accuracy, as well as (b) a high model reliability.Comment: To be published in the proceedings of the 12th International
Symposium on Software Engineering for Adaptive and Self-Managing Systems
(SEAMS'17
A Centralized Mechanism to Make Predictions Based on Data From Multiple WSNs
In this work, we present a method that exploits a scenario with
inter-Wireless Sensor Networks (WSNs) information exchange by making
predictions and adapting the workload of a WSN according to their outcomes. We
show the feasibility of an approach that intelligently utilizes information
produced by other WSNs that may or not belong to the same administrative
domain. To illustrate how the predictions using data from external WSNs can be
utilized, a specific use-case is considered, where the operation of a WSN
measuring relative humidity is optimized using the data obtained from a WSN
measuring temperature. Based on a dedicated performance score, the simulation
results show that this new approach can find the optimal operating point
associated to the trade-off between energy consumption and quality of
measurements. Moreover, we outline the additional challenges that need to be
overcome, and draw conclusions to guide the future work in this field.Comment: 10 pages, simulation results and figures. Published i
Deep Adaptive Feature Embedding with Local Sample Distributions for Person Re-identification
Person re-identification (re-id) aims to match pedestrians observed by
disjoint camera views. It attracts increasing attention in computer vision due
to its importance to surveillance system. To combat the major challenge of
cross-view visual variations, deep embedding approaches are proposed by
learning a compact feature space from images such that the Euclidean distances
correspond to their cross-view similarity metric. However, the global Euclidean
distance cannot faithfully characterize the ideal similarity in a complex
visual feature space because features of pedestrian images exhibit unknown
distributions due to large variations in poses, illumination and occlusion.
Moreover, intra-personal training samples within a local range are robust to
guide deep embedding against uncontrolled variations, which however, cannot be
captured by a global Euclidean distance. In this paper, we study the problem of
person re-id by proposing a novel sampling to mine suitable \textit{positives}
(i.e. intra-class) within a local range to improve the deep embedding in the
context of large intra-class variations. Our method is capable of learning a
deep similarity metric adaptive to local sample structure by minimizing each
sample's local distances while propagating through the relationship between
samples to attain the whole intra-class minimization. To this end, a novel
objective function is proposed to jointly optimize similarity metric learning,
local positive mining and robust deep embedding. This yields local
discriminations by selecting local-ranged positive samples, and the learned
features are robust to dramatic intra-class variations. Experiments on
benchmarks show state-of-the-art results achieved by our method.Comment: Published on Pattern Recognitio
Design of an Efficient Interconnection Network of Temperature Sensors
Temperature has become a first class design constraint because high temperatures adversely affect circuit reliability, static power and degrade the performance. In this scenario, thermal characterization of ICs and on-chip temperature monitoring represent fundamental tasks in electronic design. In this work, we analyze the features that an interconnection network of temperature sensors must fulfill. Departing from the network topology, we continue with the proposal of a very light-weight network architecture based on digitalization resource sharing. Our proposal supposes a 16% improvement in area and power consumption compared to traditional approache
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