Poincare gauge invariance and gravitation in Minkowski spacetime

A formulation of Poincare symmetry as an inner symmetry of field theories defined on a fixed Minkowski spacetime is given. Local P gauge transformations and the corresponding covariant derivative with P gauge fields are introduced. The renormalization properties of scalar, spinor and vector fields in P gauge field backgrounds are determined. A minimal gauge field dynamics consistent with the renormalization constraints is given.Comment: 36 pages, latex-fil

Statistical analysis of discrimination games

The hypothesis that meanings originate from discrimination tasks, in which an individual attempts to categorize N objects using a set of M sensory channels, is examined within a quantitative statistical perspective. Failure in discrimination triggers the refinement of a randomly-chosen sensory channel, starting thus an ongoing process, termed discrimination game, that ends only when all objects are differentiated. We show that the expected number of trials of a discrimination game diverges in the case of a single channel and scales with the power N 2/M for M ≥2. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 200689.75.Fb Structures and organization in complex systems, 02.50.Ey Stochastic processes, 02.50.Le Decision theory and game theory,

Grounding Robot Sensory and Symbolic Information Using the Semantic Web

Abstract. Robots interacting with other agents in dynamic environments require robust knowledge management capabilities if they are to communicate, learn and exhibit intelligent behaviour. Symbol grounding involves creating, and maintaining, the linkages between internal symbols used for decision making with the real world phenomena to which those symbols refer. We implement grounding using ontologies designed for the Semantic Web. We use SONY AIBO robots and the robot soccer domain to illustrate our approach. Ontologies can provide an important bridge between the perceptual level and the symbolic level and in so doing they can be used to ground sensory information. A major advantage of using ontologies to ground sensory and symbolic information is that they enhance interoperability, knowledge sharing, knowledge reuse and communication between agents. Once objects are grounded in ontologies, Semantic Web technologies can be used to access, build, derive, and manage robot knowledge.