15,019 research outputs found
Supervised learning on graphs of spatio-temporal similarity in satellite image sequences
High resolution satellite image sequences are multidimensional signals
composed of spatio-temporal patterns associated to numerous and various
phenomena. Bayesian methods have been previously proposed in (Heas and Datcu,
2005) to code the information contained in satellite image sequences in a graph
representation using Bayesian methods. Based on such a representation, this
paper further presents a supervised learning methodology of semantics
associated to spatio-temporal patterns occurring in satellite image sequences.
It enables the recognition and the probabilistic retrieval of similar events.
Indeed, graphs are attached to statistical models for spatio-temporal
processes, which at their turn describe physical changes in the observed scene.
Therefore, we adjust a parametric model evaluating similarity types between
graph patterns in order to represent user-specific semantics attached to
spatio-temporal phenomena. The learning step is performed by the incremental
definition of similarity types via user-provided spatio-temporal pattern
examples attached to positive or/and negative semantics. From these examples,
probabilities are inferred using a Bayesian network and a Dirichlet model. This
enables to links user interest to a specific similarity model between graph
patterns. According to the current state of learning, semantic posterior
probabilities are updated for all possible graph patterns so that similar
spatio-temporal phenomena can be recognized and retrieved from the image
sequence. Few experiments performed on a multi-spectral SPOT image sequence
illustrate the proposed spatio-temporal recognition method
Developmental Bayesian Optimization of Black-Box with Visual Similarity-Based Transfer Learning
We present a developmental framework based on a long-term memory and
reasoning mechanisms (Vision Similarity and Bayesian Optimisation). This
architecture allows a robot to optimize autonomously hyper-parameters that need
to be tuned from any action and/or vision module, treated as a black-box. The
learning can take advantage of past experiences (stored in the episodic and
procedural memories) in order to warm-start the exploration using a set of
hyper-parameters previously optimized from objects similar to the new unknown
one (stored in a semantic memory). As example, the system has been used to
optimized 9 continuous hyper-parameters of a professional software (Kamido)
both in simulation and with a real robot (industrial robotic arm Fanuc) with a
total of 13 different objects. The robot is able to find a good object-specific
optimization in 68 (simulation) or 40 (real) trials. In simulation, we
demonstrate the benefit of the transfer learning based on visual similarity, as
opposed to an amnesic learning (i.e. learning from scratch all the time).
Moreover, with the real robot, we show that the method consistently outperforms
the manual optimization from an expert with less than 2 hours of training time
to achieve more than 88% of success
Dealing with uncertain entities in ontology alignment using rough sets
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Ontology alignment facilitates exchange of knowledge among heterogeneous data sources. Many approaches to ontology alignment use multiple similarity measures to map entities between ontologies. However, it remains a key challenge in dealing with uncertain entities for which the employed ontology alignment measures produce conflicting results on similarity of the mapped entities. This paper presents OARS, a rough-set based approach to ontology alignment which achieves a high degree of accuracy in situations where uncertainty arises because of the conflicting results generated by different similarity measures. OARS employs a combinational approach and considers both lexical and structural similarity measures. OARS is extensively evaluated with the benchmark ontologies of the ontology alignment evaluation initiative (OAEI) 2010, and performs best in the aspect of recall in comparison with a number of alignment systems while generating a comparable performance in precision
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