On Chemical Activity Foundations of a classificatory approach to the study of chemical combination

Estructura y actividad son conceptos centrales y sin embargo ambiguos de la química que admiten una variedad de denotaciones distintas. La popular (aún si raramente explícita) identificación de estructura química con una teoría atómica de la constitución de la materia que da cuenta de su comportamiento durante el cambio químico entra en conflicto con perspectivas contemporáneas en la historia y la filosofía de la química. Al mismo tiempo, trivializa el concepto de actividad química, privándolo de cualquier dimensión teórica relevante. En contra de esta perspectiva definimos estructura y actividad como aproximaciones epistémicas opuestas, caracterizadas por otorgar prioridades ontológicas inversas a los conceptos de relación y propiedad, que interactúan en la teoría química. La prioridad dada a las relaciones como determinantes de las propiedades de las sustancias característica de la teoría de la actividad química motiva una matematización peculiar de esta aproximación epistémica, usando los formalismos de la teoría de categorías, el análisis formal de conceptos, y el análisis de redes. El formalismo matemático resultante permite o sugiere una reconstrucción exitosa de constructos químicos clave tales como ácido, base, y función orgánica, provee los fundamentos de una metodología para el análisis de similitud entre sustancias vistas como objetos en una red de reacciones químicas, y revela el potencial de la actividad química como una auténtica teoría de la combinación química, complementaria a la teoría estructural y perfectamente capaz de construir conocimiento químico por sus propios medios. / Abstract. Structure and activity are central yet ambiguous concepts of chemical science, being susceptible to a variety of distinct denotations. The popular (though seldom explicit) attachment of chemical structure to an atomic constitution theory that accounts for the behavior of matter as it undergoes chemical change conicts with contemporary perspectives in the history and philosophy of chemistry and trivializes the concept of chemical activity, depriving it of any relevant theoretical dimension. Against this perspective, we define structure and activity as opposing epistemic approaches that interplay in chemical theory and are characterized by reverse ontological priorities ascribed to the concepts of property and relation. The prioritization of relations as determinants of substance properties characteristic of chemical activity theory motivates a peculiar mathematization of this epistemic approach, using the formalisms of category theory, formal concept analysis, and network analysis. The resulting mathematical formalism allows or suggests the possibility of a successful reconstruction of key chemical constructs such as acid, base, and organic function; provides the foundation of a methodology for the analysis of similarity in chemical reaction networks; and unveils the potential of chemical activity as a fully-eshed theory of chemical combination, complementary to structure theory and readily capable of constructing chemical knowledge by its own means.Doctorad

Efficient Image Segmentation and Segment-Based Analysis in Computer Vision Applications

This dissertation focuses on efficient image segmentation and segment-based object recognition in computer vision applications. Special attention is devoted to analyzing shape, of particular importance for our two applications: plant species identification from leaf photos, and object classification in remote sensing images. Additionally, both problems are bound by efficiency, constraining the choice of applicable methods: leaf recognition results are to be used within an interactive system, while remote sensing image analysis must scale well over very large image sets. Leafsnap was the first mobile app to provide automatic recognition of tree species, currently counting with over 1.7 million downloads. We present an overview of the mobile app and corresponding back end recognition system, as well as a preliminary analysis of user-submitted data. More than 1.7 million valid leaf photos have been uploaded by users, 1.3 million of which are GPS-tagged. We then focus on the problem of segmenting photos of leaves taken against plain light-colored backgrounds. These types of photos are used in practice within Leafsnap for tree species recognition. A good segmentation is essential in order to make use of the distinctive shape of leaves for recognition. We present a comparative experimental evaluation of several segmentation methods, including quantitative and qualitative results. We then introduce a custom-tailored leaf segmentation method that shows superior performance while maintaining computational efficiency. The other contribution of this work is a set of attributes for analysis of image segments. The set of attributes is designed for use in knowledge-based systems, so they are selected to be intuitive and easily describable. The attributes can also be computed efficiently, to allow applicability across different problems. We experiment with several descriptive measures from the literature and encounter certain limitations, leading us to introduce new attribute formulations and more efficient computational methods. Finally, we experiment with the attribute set on our two applications: plant species identification from leaf photos and object recognition in remote sensing images

Conceptual Knowledge Representation and Reasoning

One of the main areas in knowledge representation and logic-based artificial intelligence concerns logical formalisms that can be used for representing and reasoning with concepts. For almost 30 years, since research in this area began, the issue of intensionality has had a special status in that it has been considered to play an important role, yet it has not been precisely established what it means for a logical formalism to be intensional. This thesis attempts to set matters straight. Based on studies of the main contributions to the issue of intensionality from philosophy of language, in particular the works of Gottlob Frege and Rudolf Carnap, we start by defining when a logical formalism is intensional. We then examine whether the current formalizations of concepts are intensional. The result is negative in the sense that none of the prevalent formalizations are intensional. This motivates the development of intensional logics for concepts. Our main contribution is the presentation of such an intensional concept logic