Ontology-based representation and generation of workflows for micro-task human-machine computation

Doctoral Program in Computer Science

Combining data mining and evolutionary computation for multi-criteria optimization of earthworks

Earthworks tasks aim at levelling the ground surface at a target construction area and precede any kind of structural construction (e.g., road and railway construction). It is comprised of sequential tasks, such as excavation, transportation, spreading and compaction, and it is strongly based on heavy mechanical equipment and repetitive processes. Under this context, it is essential to optimize the usage of all available resources under two key criteria: the costs and duration of earthwork projects. In this paper, we present an integrated system that uses two artificial intelligence based techniques: data mining and evolutionary multi-objective optimization. The former is used to build data-driven models capable of providing realistic estimates of resource productivity, while the latter is used to optimize resource allocation considering the two main earthwork objectives (duration and cost). Experiments held using real-world data, from a construction site, have shown that the proposed system is competitive when compared with current manual earthwork design.

Secure multiParty computation protocols

Dissertação de Mestrado em Engenharia Informática

Abstract computation in schizophrenia detection through artificial neural network based systems

Schizophrenia stands for a long-lasting state of mental uncertainty that may bring to an end the relation among behavior, thought, and emotion; that is, it may lead to unreliable perception, not suitable actions and feelings, and a sense of mental fragmentation. Indeed, its diagnosis is done over a large period of time; continuos signs of the disturbance persist for at least 6 (six) months. Once detected, the psychiatrist diagnosis is made through the clinical interview and a series of psychic tests, addressed mainly to avoid the diagnosis of other mental states or diseases. Undeniably, the main problem with identifying schizophrenia is the difficulty to distinguish its symptoms from those associated to different untidiness or roles. Therefore, this work will focus on the development of a diagnostic support system, in terms of its knowledge representation and reasoning procedures, based on a blended of Logic Programming and Artificial Neural Networks approaches to computing, taking advantage of a novel approach to knowledge representation and reasoning, which aims to solve the problems associated in the handling (i.e., to stand for and reason) of defective information.

Los entornos virtuales como herramienta sustituta del laboratorio "real" y como complemento de la enseñanza de Química a alumnos de Ingeniería. Virtual environments as substitute tools for the "conventional" laboratories and as a complement for Chemistry teaching to Engineering students.

El presente proyecto se plantea el siguiente problema de investigación:¿Cuál es la eficacia de los entornos virtuales de enseñanza para optimizar los aprendizajes de Química? Se sostiene la hipótesis de que los entornos virtuales de enseñanza, empleados como mediación instrumental, son eficaces para optimizar los aprendizajes de química, particularmente facilitando la vinculación y reversibilidad entre "mundo micro y macroscópico"; capacidad que usualmente sólo se atribuye al trabajo experimental de laboratorio. Los objetivos propuestos son: Determinar la eficacia de entornos virtuales de enseñanza, como mediaciones instrumentales, para optimizar los aprendizajes de química en estudiantes de ingeniería. Implementar un entrono virtual de enseñanza de química, diseñado como mediación instrumental y destinado a estudiantes de dos carreras de ingeniería del IUA. Evaluar el desarrollo y los resultados de la innovación introducida. Comparar los resultados de la innovación con los resultados de la enseñanza usual. Derivar conclusiones acerca de la eficacia de la innovación propuesta. Socializar el conocimiento producido en ámbitos científico-tecnológicos reconocidos. Se generará un aula virtual en plataforma Educativa y utilidzando el laboratorio de computación de la institución se buscará desarrollar laboratorios virtuales donde se propondrán actividades de simulación de trabajo experimental. Los resultados esperados son: - Un Aula Virtual que cumpla funciones análogas a las de un laboratorio experimental. - Información válida y confiable acerca de la eficacia de la misma como medio para optimizar los aprendizajes de química. - Publicaciones en ámbitos científico-tecnológicos reconocidos que sometan a juicio público la innovación y la investigación efectuadas. La importancia del proyecto radica principalmente en poner a prueba la eficacia de los entornos virtuales para optimizar los aprendizajes de química, analogando tareas usualmente limitadas al trabajo experimental de laboratorio. Su pertinencia apunta a un replanteo del curriculo de los cursos de Química para estudiantes de Ingeniería.

Càlcul distribuït en BOINC per el trencament de l'algorisme RC5

Aquest projecte té com a objectiu participar en el desafiament d'RSA Laboratories corresponent a trencar el criptosistema RC5-32-12-9 proposat. Per realitzar-ho s'ha triat realitzar un atac per força bruta, mitjançant el càlcul distribuït i, més concretament, utilitzant la Public Resource Computing. La plataforma escollida és la Berkeley Open Infrastructure for Network Computing (BOINC), coneguda per la seva utilització en grans projectes com ara SETI@home. En aquest projecte es posa en funcionament la infraestructura i es desenvolupen les aplicacions necessàries per iniciar els càlculs que haurien de permetre el trencament del criptosistema.

A comparison of simian rotavirus SA11 preparations maintained in different laboratories

Preparations of simian SA11 maintained in different laboratories were compared with each other by polyacrylamide gel electrophoresis of genomic RNA. Differences in the migration of genome segments 4,5 and 7 allowed the classification of eight virus preparations into four electrophoretic types.

Computation of an integral basis of a quartic number field

"Vegeu el resum a l'inici del document del fitxer adjunt."

Computation of an integral basis of quartic number field

"Vegeu el resum a l'inici del document del fitxer ajunt."

Fast numerical algorithms for the computation of invariant tori in Hamiltonian systems

In this paper, we develop numerical algorithms that use small requirements of storage and operations for the computation of invariant tori in Hamiltonian systems (exact symplectic maps and Hamiltonian vector fields). The algorithms are based on the parameterization method and follow closely the proof of the KAM theorem given in [LGJV05] and [FLS07]. They essentially consist in solving a functional equation satisfied by the invariant tori by using a Newton method. Using some geometric identities, it is possible to perform a Newton step using little storage and few operations. In this paper we focus on the numerical issues of the algorithms (speed, storage and stability) and we refer to the mentioned papers for the rigorous results. We show how to compute efficiently both maximal invariant tori and whiskered tori, together with the associated invariant stable and unstable manifolds of whiskered tori. Moreover, we present fast algorithms for the iteration of the quasi-periodic cocycles and the computation of the invariant bundles, which is a preliminary step for the computation of invariant whiskered tori. Since quasi-periodic cocycles appear in other contexts, this section may be of independent interest. The numerical methods presented here allow to compute in a unified way primary and secondary invariant KAM tori. Secondary tori are invariant tori which can be contracted to a periodic orbit. We present some preliminary results that ensure that the methods are indeed implementable and fast. We postpone to a future paper optimized implementations and results on the breakdown of invariant tori.