SomeRDFS in the Semantic Web

The Semantic Web envisions a world-wide distributed architecture where computational resources will easily inter-operate to coordinate complex tasks such as query answering. Semantic marking up of web resources using ontologies is expected to provide the necessary glue for making this vision work. Using ontology languages, (communities of) users will build their own ontologies in order to describe their own data. Adding semantic mappings between those ontologies, in order to semantically relate the data to share, gives rise to the Semantic Web: data on the web that are annotated by ontologies networked together by mappings. In this vision, the Semantic Web is a huge semantic peer data management system. In this paper, we describe the SomeRDFS peer data management systems that promote a "simple is beautiful" vision of the Semantic Web based on data annotated by RDFS ontologies

Semantic Interoperability of Geospatial Ontologies: A Model-theoretic Analysis

People sometimes misunderstand each other, even when they use the same language to communicate. Often these misunderstandings happen when people use the same words to mean different things, in effect disagreeing about meanings. This thesis investigates such disagreements about meaning, considering them to be issues of semantic interoperability. This thesis explores semantic interoperability via a particular formal framework used to specify people’s conceptualizations of a given domain. This framework is called an ‘ontology,’ which is a collection of data and axioms written in a logical language equipped with a modeltheoretic semantics. The domain under consideration is the geospatial domain. Specifically, this thesis investigates to what extent two geospatial ontologies are semantically interoperable when they ‘agree’ on the meanings of certain basic terms and statements, but ‘disagree’ on others. This thesis defines five levels of semantic interoperability that can exist between two ontologies. Each of these levels is, in turn, defined in terms of six ‘compatibility conditions,’ which precisely describe how the results of queries to one ontology are compatible with the results of queries to another ontology. Using certain assumptions of finiteness, the semantics of each ontology is captured by a finite number of models, each of which is also finite. The set of all models of a given ontology is called its model class. The five levels of semantic interoperability are proven to correspond exactly to five particular relationships between the model classes of the ontologies. The exact level of semantic interoperability between ontologies can in some cases be computed; in other cases a heuristic can be used to narrow the possible levels of semantic interoperability. The main results are: (1) definitions of five levels of semantic interoperability based on six compatibility conditions; (2) proofs of the correspondence between levels of semantic interoperability and the model-class relation between two ontologies; and (3) a method for computing, given certain assumptions of finiteness, the exact level of semantic interoperability between two ontologies. These results define precisely, in terms of models and queries, the often poorly defined notion of semantic interoperability, thus providing a touchstone for clear definitions of semantic interoperability elsewhere

Mejoras en la usabilidad de la web a través de una estructura complementaria

La Web ha motivado la generación de herramientas que permiten, con distintos grados de sofisticación y precisión, manipular sus contenidos. Para ello, tratan una serie de problemas, relacionados con la naturaleza imperfecta y cambiante de todas las actividades humanas. Ésta se refleja en fenómenos como las ambigüedades, contradicciones y errores de los textos almacenados. Esta tesis presenta una propuesta para complementar la administración de contenidos en la Web y de esta manera facilitar el proceso de recuperación de información. Se presenta un prototipo, denominado Web Intelligent Handler (WIH), que implementa una serie de algoritmos básicos para manipular algunas características morfosintácticas de textos en castellano y, en base a ellas, obtener una representación resumida y alternativa de su contenido. En este contexto, se define una nueva métrica de ponderación para reflejar parte de la esencia morfosintáctica de los sintagmas. Además se define un esquema de interacción entre los módulos para regular la explotación de los textos. También se explora la capacidad de los algoritmos propuestos en el tratamiento de los textos, considerándolos como una colección de sintagmas, sujeta a factores tales como contradicciones, ambigüedades y errores. Otro aporte de esta tesis es la posibilidad de evaluar matemáticamente y de manera automática tipos de estilos de texto y perfiles de escritura. Se proponen los estilos literario, técnico y mensajes. También se proponen los perfiles documento, foro de intercambio, índice Web y texto de sitio blog. Se evalúan los tres estilos y los cuatro perfiles mencionados, los que se comportan como distintos grados de una escala de estilos y perfiles, respectivamente, cuando se los evalúa con la métrica morfosintáctica aquí definida. Adicionalmente, utilizando la misma métrica, es posible realizar una valoración aproximada y automática de la calidad de cualquier tipo de texto. Esta calificación resulta ser invariante a la cantidad de palabras, temática y perfil, pero relacionada con el estilo del escrito en cuestión.The Web motivated a set of tools for content handling with several levels of sophistication and precision. To do so, they deal with many unsolved problems in saved texts. All of them are related to the mutable and imperfect essence of human beings such as ambiguities, contradictions and misspellings. This theses presents a proposal to complement the Web content management and therefore to provide support to the information retrieval activity. A prototype named Web Intelligent Handler (WIH) is introduced to implement a set of algorithms that manage some morpho-syntactical features in Spanish texts. These features are also used to get a brief and alternate representation of its content. Within this framework, a new weighting metric is designed to reflect part of the syntagm morpho-syntactical essence. A module interaction approach is also outlined to rule the text processing output. Besides, this thesis analyzes the algorithms ability to handle texts considering them as a collection of syntagms affected by certain factors such as contradictions, ambiguities and misspellings. Perhaps, the main contribution of this thesis is the possibility to automatically mathematical evaluation of text styles and profiles. Three initial three styles are proposed here: literary, technical and message. Furthermore, the following writer profiles are proposed also: document, foro, Web-index and blog. All the three styles and four profiles were evaluated. They behave respectively as a part of a graduated scale of styles and profiles when the morpho-syntactical metric defined here is used. It is also possible to perform a kind of automatic rough text quality valuation. This is invariant to the text word quantity, topic and profile, but it is related to its style.Facultad de Informátic