Attention mechanisms in the CHREST cognitive architecture

In this paper, we describe the attention mechanisms in CHREST, a computational architecture of human visual expertise. CHREST organises information acquired by direct experience from the world in the form of chunks. These chunks are searched for, and verified, by a unique set of heuristics, comprising the attention mechanism. We explain how the attention mechanism combines bottom-up and top-down heuristics from internal and external sources of information. We describe some experimental evidence demonstrating the correspondence of CHREST’s perceptual mechanisms with those of human subjects. Finally, we discuss how visual attention can play an important role in actions carried out by human experts in domains such as chess

Dynamical Systems approach to Saffman-Taylor fingering. A Dynamical Solvability Scenario

A dynamical systems approach to competition of Saffman-Taylor fingers in a channel is developed. This is based on the global study of the phase space structure of the low-dimensional ODE's defined by the classes of exact solutions of the problem without surface tension. Some simple examples are studied in detail, and general proofs concerning properties of fixed points and existence of finite-time singularities for broad classes of solutions are given. The existence of a continuum of multifinger fixed points and its dynamical implications are discussed. The main conclusion is that exact zero-surface tension solutions taken in a global sense as families of trajectories in phase space spanning a sufficiently large set of initial conditions, are unphysical because the multifinger fixed points are nonhyperbolic, and an unfolding of them does not exist within the same class of solutions. Hyperbolicity (saddle-point structure) of the multifinger fixed points is argued to be essential to the physically correct qualitative description of finger competition. The restoring of hyperbolicity by surface tension is discussed as the key point for a generic Dynamical Solvability Scenario which is proposed for a general context of interfacial pattern selection.Comment: 3 figures added, major rewriting of some sections, submitted to Phys. Rev.

Research Perspectives for Logic and Deduction

The article is meant to be kind of the author's manifesto for the role of logic and deduction within Intellectics. Based on a brief analysis of this role the paper presents a number of proposals for future scientic research along the various di-mensions in the space of logical explorations. These dimensions include the range of possible applications including modelling intelligent behavior, the grounding of logic in some semantic context, the choice of an appropriate logic from the great variety of alternatives, then the choice of an appropriate formal system for repre-senting the chosen logic, and nally the issue of developing the most ecient search strategies. Among the proposals is a conjecture concerning the treatment of cuts in proof search. Often a key advance is a matter of applying a small change to a single formula. Ray Kurzweil [Kur05, p.5]

Influence of polymer packaging on the aroma of strawberry syrup

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Applications of ?Artificial Intelligence? for Chemical Inference, VI. Approach to a General Method of Interpreting Low Resolution Mass Spectra with a Computer

Le programme connu sous le nom de «Heuristic DENDRAL» est maintenant capable d'interpréter d'une manière absolument automatique les spectres de masse à basse résolution de n'importe quel composé de formule élémentaire CnH2n+vX (X = 0, S ou N, v = valence de X). La possibilité de faire usage de spectres de RMN. pour faciliter l'interprétation a été retenue. Il n'est plus nécessaire de fournir au programme la formule élémentaire du composé dont on veut déterminer la structure. Les données théoriques concernant la spectrométrie de masse et la résonance magnétique nucléaire sont créées par le programme lui-même. A aucun moment le chimiste n'a besoin de fournir d'autres données que le spectre de masse et, s'il le désire, le spectre de RMN. L'efficacité du programme a été mise à l'épreuve avec 210 spectres de masse. La structure correcte apparaît toujours dans la réponse. Les résultats reportés dans les tableaux 2, 3 et 4 montrent que le nombre d'isomères qui sont compatibles avec la réponse donnée par le programme représente une très importante réduction du nombre total d'isomères qui sont a priori des candidats possibles