Ontology-based access to sensor data streams

Sensor networks are increasingly becoming one of the main sources of Big Data on the Web. However, the observations that they produce are made available with heterogeneous schemas, vocabularies and data formats, making it difficult to share and reuse these data for other purposes than those for which they were originally set up. In this thesis we address these challenges, considering how we can transform streaming raw data to rich ontology-based information that is accessible through continuous queries for streaming data. Our main contribution is an ontology-based approach for providing data access and query capabilities to streaming data sources, allowing users to express their needs at a conceptual level, independent of implementation and language-specific details. We introduce novel query rewriting and data translation techniques that rely on mapping definitions relating streaming data models to ontological concepts. Specific contributions include: • The syntax and semantics of the SPARQLStream query language for ontologybased data access, and a query rewriting approach for transforming SPARQLStream queries into streaming algebra expressions. • The design of an ontology-based streaming data access engine that can internally reuse an existing data stream engine, complex event processor or sensor middleware, using R2RML mappings for defining relationships between streaming data models and ontology concepts. Concerning the sensor metadata of such streaming data sources, we have investigated how we can use raw measurements to characterize streaming data, producing enriched data descriptions in terms of ontological models. Our specific contributions are: • A representation of sensor data time series that captures gradient information that is useful to characterize types of sensor data. • A method for classifying sensor data time series and determining the type of data, using data mining techniques, and a method for extracting semantic sensor metadata features from the time series.

Unified access to media metadata on the web: Towards interoperability using a core vocabulary.

The goal of the W3C's Media Annotation Working Group (MAWG) is to promote interoperability between multimedia metadata formats on the Web. As experienced by everybody, audiovisual data is omnipresent on today's Web. However, different interaction interfaces and especially diverse metadata formats prevent unified search, access, and navigation. MAWG has addressed this issue by developing an interlingua ontology and an associated API. This article discusses the rationale and core concepts of the ontology and API for media resources. The specifications developed by MAWG enable interoperable contextualized and semantic annotation and search, independent of the source metadata format, and connecting multimedia data to the Linked Data cloud. Some demonstrators of such applications are also presented in this article.

Género y transporte: análisis de la movilidad del cuidado como punto de partida para construir una base de conocimiento más amplia de los patrones de movilidad. El caso de Madrid

Las limitaciones en la capacidad de movilidad pueden ser consideradas en la actualidad como una forma de discriminación tremenda y a la vez invisible dentro de la sociedad. Para poder evitar esta discriminación es necesario que las políticas de transporte, que hasta ahora han basado sus actuaciones particularmente sobre las necesidades de acceso al empleo, reconozcan las exigencias de las personas dependientes y de aquellas que realizan las tareas no remuneradas del cuidado de otros y de atención a la familia. Las personas que trabajan en las tareas domésticas, en la mayoría de los casos mujeres, tienen muchas dificultades para sincronizar sus obligaciones con los tiempos y las distancias. Estas personas desempeñan un trabajo diario, que tiene lugar tanto fuera como dentro del hogar y tienen necesidades específicas de movilidad. El problema principal es que este tipo de trabajo no suele ser tomado en consideración, ya que no entra en la esfera del trabajo remunerado. Pero es una labor que está estrictamente ligada a la actividad de la sociedad y es un elemento indispensable para el funcionamiento de la vida urbana. Es un trabajo real, que tiene lugar en el espacio urbano, que exige un considerable esfuerzo físico y emocional, y que ayuda a garantizar la calidad de la vida cotidiana. Es un aspecto indispensable a tener en cuenta en el ejercicio de las políticas públicas y sociales. Sobre la base de estas consideraciones se introduce el concepto “Movilidad del cuidado” (Sánchez de Madariaga, 2009a y 2009b), mediante el cual se reconoce la necesidad de evaluar y hacer visible los desplazamientos diarios asociados con el trabajo del cuidado. Por trabajo del cuidado se entiende el trabajo no remunerado, realizado por los adultos para los niños u otras personas dependientes, incluido el trabajo relacionado con el mantenimiento del hogar. El análisis de este tipo de viajes exige ciertos cambios significativos en las formas de recoger datos estadísticos. No se trata solo de sumar los desplazamientos que actualmente aparecen en las estadísticas como viajes de compras, acompañamiento, gestiones, cuidado de otros, etc. El problema es que los datos sobre movilidad se recogen con una serie de sesgos que infravaloran los viajes de cuidado: las estadísticas no cuentan los viajes cortos a pie y tampoco reflejan bien los viajes encadenados, ambos típicamente femeninos; no se deslindan con precisión los viajes de cuidado de otro tipo de viajes, de manera que muchos desplazamientos relacionados con la esfera reproductiva aparecen como viajes personales o de ocio y en muchos casos se encasillan en la categoría otros. Mediante esta investigación se pretende estimar el peso que la movilidad del cuidado tiene en el total de la movilidad y describirla de manera precisa en un contexto geográfico determinado, en el caso específico Madrid. Los estudios sobre el tema realizados hasta el momento reconocen la necesidad de llevar a cabo encuestas de movilidad que tengan en cuenta las variables socio económicas que caracterizan a la población y también se demanda la segregación de los datos recogidos por sexo, así como el uso del género como una categoría analítica. Igualmente es indispensable atribuir la misma importancia que tienen los viajes relacionados con la esfera productiva a los que están relacionados con la esfera reproductiva. No obstante, es solo mediante la introducción del concepto de “movilidad del cuidado” que se propone una nueva categorización de los motivos de desplazamiento dentro de las “clásicas” encuestas de movilidad y, por primera vez, mediante esta investigación se aplica este concepto a un ejemplo práctico a partir del cual queda en evidencia la necesidad de un cambio de enfoque en las políticas de transporte. Así, a través el uso de encuestas cuantitativas y cualitativas realizadas ad hoc sobre la base de la metodología propuesta, se capturan los patrones de viajes significativos para poder describir en maneara exhaustiva la movilidad de las personas que tienen responsabilidades de cuidado. El objetivo es crear una base de conocimiento más amplia sobre los patrones de movilidad, comportamientos y necesidades, además de mejorar los conceptos operacionales y establecer políticas de transporte más equitativas, que respondan de mejor manera a las necesidades de género, beneficiando así a toda la sociedad. ABSTRACT Nowadays, limitations in urban mobility can be considered as some type of extreme discrimination, which remains invisible to the society. In order to avoid this kind of discrimination, new transport policies are required, especially considering that so far they have been based and organized particularly in relation to the needs derived from the access to employment. These policies must take into account the demands of people depending on the support of others as well as of unpaid caregivers in charge of looking after other individuals and taking care of the family. Most of the people devoted to domestic work, which in the vast majority of cases is carried out by women, find it difficult to coordinate their obligations with time and distances. These people carry out a daily job that takes place both inside their homes as well as outside, and they have specific mobility needs. The main issue is that this type of work is usually not taken into consideration, since it is not included under the scope of paid employment. However, this work is strictly related to the activities of society and is therefore a crucial element in the functioning of urban life. It is an actual job that takes place in an urban space, requires a considerable amount of physical and emotional effort and guarantees quality of life on a daily basis. This is an important aspect that should be taken into account when drafting public and social policies. The concept of “Mobility of care” (Sánchez de Madariaga, 2009a and 2009b) is introduced under these considerations. This concept acknowledges the need to evaluate and identify daily movements from one place to another that are related to caregiving. Caregiving is understood, in this case, as unpaid work that is carried out by adults for children and other people that depend on the support of others, and it also includes duties related to home maintenance. The analysis of these types of movements requires some significant changes in the way in which statistic data is gathered. The idea is to not only add up the movements that appear in statistics such as shopping trips, accompanying someone, dealings, caregiving, etc. The problem with data on mobility is that it is gathered with bias that undervalues mobility related to caregiving: statistics do not take into consideration short trips that are made walking nor do they properly reflect connected trips, both of which are typically feminine; moreover, there is an imprecise differentiation of trips related to caregiving and other kind of trips, and because of that, many of the trips related to the reproductive sphere are considered personal or recreational trips, and are many times labelled as others. This investigation aims to evaluate the importance that mobility of care has in mobility in general, describing it in a precise manner within a specific geographical context that in this case is Madrid. To this date, most of the studies on this subject have acknowledged the need to carry out mobility surveys that include socio economic variables that characterize the population and they have also requested that collected data is segregated by sex and that gender is used as an analytical category. Likewise, it is fundamental to give the same importance to mobility related to the sphere of reproduction as to that related to the sphere of productiveness. However, it is only through the implementation of the concept of “mobility of care” that a new categorization of mobility, within classic mobility surveys, is proposed. Also, for the first time and by this investigation, this concept is applied to a practical case, shining a light on the need to change the focus of transport policies. Through the use of ad hoc quantitative and qualitative surveys based on the proposed methodology, the patterns of relevant movements are identified in order to thoroughly describe the mobility of people responsible of caregiving. The aim is to create a broader knowledge base on patterns of mobility, behaviour and necessities, in addition to improving functional concepts and transport policies to make them more equitable and responsive to gender needs, thus benefitting society as a whole.

Developing front-end Web 2.0 technologies to access services, content and things in the future Internet

The future Internet is expected to be composed of a mesh of interoperable web services accessible from all over the web. This approach has not yet caught on since global user?service interaction is still an open issue. This paper states one vision with regard to next-generation front-end Web 2.0 technology that will enable integrated access to services, contents and things in the future Internet. In this paper, we illustrate how front-ends that wrap traditional services and resources can be tailored to the needs of end users, converting end users into prosumers (creators and consumers of service-based applications). To do this, we propose an architecture that end users without programming skills can use to create front-ends, consult catalogues of resources tailored to their needs, easily integrate and coordinate front-ends and create composite applications to orchestrate services in their back-end. The paper includes a case study illustrating that current user-centred web development tools are at a very early stage of evolution. We provide statistical data on how the proposed architecture improves these tools. This paper is based on research conducted by the Service Front End (SFE) Open Alliance initiative.