5 research outputs found
Discrete Elastic Inner Vector Spaces with Application in Time Series and Sequence Mining
This paper proposes a framework dedicated to the construction of what we call
discrete elastic inner product allowing one to embed sets of non-uniformly
sampled multivariate time series or sequences of varying lengths into inner
product space structures. This framework is based on a recursive definition
that covers the case of multiple embedded time elastic dimensions. We prove
that such inner products exist in our general framework and show how a simple
instance of this inner product class operates on some prospective applications,
while generalizing the Euclidean inner product. Classification experimentations
on time series and symbolic sequences datasets demonstrate the benefits that we
can expect by embedding time series or sequences into elastic inner spaces
rather than into classical Euclidean spaces. These experiments show good
accuracy when compared to the euclidean distance or even dynamic programming
algorithms while maintaining a linear algorithmic complexity at exploitation
stage, although a quadratic indexing phase beforehand is required.Comment: arXiv admin note: substantial text overlap with arXiv:1101.431
Interpr\'etation vague des contraintes structurelles pour la RI dans des corpus de documents XML - \'Evaluation d'une m\'ethode approch\'ee de RI structur\'ee
We propose specific data structures designed to the indexing and retrieval of
information elements in heterogeneous XML data bases. The indexing scheme is
well suited to the management of various contextual searches, expressed either
at a structural level or at an information content level. The approximate
search mechanisms are based on a modified Levenshtein editing distance and
information fusion heuristics. The implementation described highlights the
mixing of structured information presented as field/value instances and free
text elements. The retrieval performances of the proposed approach are
evaluated within the INEX 2005 evaluation campaign. The evaluation results rank
the proposed approach among the best evaluated XML IR systems for the VVCAS
task.Comment: 26 pages, ISBN 978-2-7462-1969-
Spiral Walk on Triangular Meshes : Adaptive Replication in Data P2P Networks
We introduce a decentralized replication strategy for peer-to-peer file
exchange based on exhaustive exploration of the neighborhood of any node in the
network. The replication scheme lets the replicas evenly populate the network
mesh, while regulating the total number of replicas at the same time. This is
achieved by self adaptation to entering or leaving of nodes. Exhaustive
exploration is achieved by a spiral walk algorithm that generates a number of
messages linearly proportional to the number of visited nodes. It requires a
dedicated topology (a triangular mesh on a closed surface). We introduce
protocols for node connection and departure that maintain the triangular mesh
at low computational and bandwidth cost. Search efficiency is increased using a
mechanism based on dynamically allocated super peers. We conclude with a
discussion on experimental validation results