Tese de mestrado integrado. Engenharia Informática e Computação. Universidade do Porto. Faculdade de Engenharia. 2011

Estágio realizado na Companhia Portuguesa de Computadores Informática e Sistemas e orientado pelo Doutor Silvino Glória / Tese de mestrado integrado. Engenharia informática e Computação. Faculdade de Engenharia. Universidade do Porto. 2008

Tesis para optar al grado de Mag?ster en Gesti?n para la Globalizaci?n / Este trabajo presenta el desarrollo de un modelo de negocios para BeautifulLogs , un gestor de logs de aplicaciones (m?viles o web) desarrolladas para una infraestructura conocida como la nube (cloud computing). El desarrollo del modelo de negocio sigue una metodolog?a basada en los m?todos Lean Startup y Customer Development, enfocada en validar con clientes reales los supuestos de un modelo de negocios y reflejando los avances y el estado de dicho modelo en un Canvas de Modelo de Negocios. Cada validaci?n se conforma de un experimento con un resultado esperado en el caso en que el supuesto sea correcto. Durante el desarrollo de este proceso para el modelo de negocios de BeautifulLogs se encontr? un espacio en el mercado (ya existente) de este tipo de herramientas, nicho basado en necesidades avanzadas que no est? siendo cubierto por las soluciones actuales. Entre estas necesidades se cuenta la necesidad de almacenar la informaci?n por m?s tiempo que las soluciones actuales (que promedian dos semanas), incrementar la potencia de las funciones de b?squeda y agregar elementos de m?tricas y anal?ticas inferidas a partir de los mismos logs. En base a estas necesidades se establecieron propuestas de valor empaquetadas en planes con un precio validado por los propios usuarios encuestados. El modelo de negocio sigue el esquema SaaS: Software como servicio por el cual el cliente paga una mensualidad (o anualidad) a cambio de su uso. Si bien los costos variables para poder ofrecer las soluciones ofrecidas en los planes resultaron ser relativamente elevados (para el mercado SaaS), existe un saludable margen entre el ingreso variable promedio por usuario (USD 143,33) y el costo variable por usuario proyectado (USD 68,13). Por otra parte, los costos de adquisici?n, la conversi?n de usuarios y el crecimiento neto de usuarios se presentan como las variables claves que determinar?n la rentabilidad del negocio, que en un escenario moderado proyecta ventas por casi un mill?n de d?lares en el octavo trimestre de vida del negocio. En su forma actual, el modelo requiere una inversi?n inicial de USD 350.000 a ocupar principalmente en desarrollo de la plataforma, as? como tambi?n en capital de trabajo. La recomendaci?n a seguir es levantar una fracci?n de esa inversi?n para efectuar una validaci?n de clientes mediante un producto m?nimo viable, que permita bajar el riesgo presentado por la variaci?n de las variables claves mencionadas anteriormente.

Memoria para optar al título de periodista / El sitio web “atrevidas.cl” es una página web donde se difunden entrevistas en formato audiovisual a mujeres jóvenes y destacadas en sus campos de trabajo. En conversaciones de no más allá de 30 minutos, la idea es relatar las experiencias, dificultades y distintos caminos que marcaron a estas personas de interes debido a su trayectoria. De esta manera, mediante una entrevista con lenguaje cotidiano y cercano, se busca entregar guías y relatos para personas que puedan ver en las entrevistadas un modelo a seguir. Con una presentación de las entrevistas principalmente en formato audiovisual, el contenido del sitio será enriquecido gracias al trabajo con herramientas multimedias. De esta forma, el proyecto busca innovar en la manera tradicional en la que usualmente se presentan las entrevistas en los medios periodísticos chilenos.

L’Internet des Objets (IoT) vise à créer un eco-système global et ubiquitaire composé d’un grand nombre d’objets hétérogènes. Afin d’atteindre cette vision, le World Wide Web apparaît comme un candidat adapté pour interconnecter objets et services à la couche applicative en un Web des Objets (WoT).Cependant l’évolution actuelle du WoT produit des silos d’objets et empêche ainsi la mise en place de cette vision. De plus, même si le Web facilite la composition d’objets et services hétérogènes, les approches existantes produisent des compositions statiques incapables de s’adapter à des environnements dynamiques et des exigences évolutives. Un autre défi est à relever: permettre aux personnes d’interagir avec le vaste, évolutif et hétérogène IoT.Afin de répondre à ces limitations, nous proposons une architecture pour IoT ouvert et autogouverné, constitué de personnes et d’objets situés, en interaction avec un environnement global via des plateformes hétérogènes. Notre approche consiste de rendre les objets autonomes et d’appliquer la métaphore des réseaux sociaux afin de créer des réseaux flexibles de personnes et d’objets. Nous fondons notre approche sur les résultats issus des domaines des multi-agents et du WoT afin de produit un WoT Social.Notre proposition prend en compte les besoins d’hétérogénéité, de découverte et d’interaction flexible dans l’IoT. Elle offre également un coût minimal pour les développeurs et les utilisateurs via différentes couches d’abstraction permettant de limité la complexité de cet éco-système. Nous démontrons ces caractéristiques par la mise en oeuvre de plus scénarios applicatifs. / The Internet of Things (IoT) aims to create a global ubiquitous ecosystem composed of large numbers of heterogeneous devices. To achieve this vision, the World Wide Web is emerging as a suitable candidate to interconnect IoT devices and services at the application layer into a Web of Things (WoT).However, the WoT is evolving towards large silos of things, and thus the vision of a global ubiquitous ecosystem is not fully achieved. Furthermore, even if the WoT facilitates mashing up heterogeneous IoT devices and services, existing approaches result in static IoT mashups that cannot adapt to dynamic environments and evolving user requirements. The latter emphasizes another well-recognized challenge in the IoT, that is enabling people to interact with a vast, evolving, and heterogeneous IoT.To address the above limitations, we propose an architecture for an open and self-governed IoT ecosystem composed of people and things situated and interacting in a global environment sustained by heterogeneous platforms. Our approach is to endow things with autonomy and apply the social network metaphor to createflexible networks of people and autonomous things. We base our approach on results from multi-agent and WoT research, and we call the envisioned IoT ecosystem the Social Web of Things.Our proposal emphasizes heterogeneity, discoverability and flexible interaction in the IoT. In the same time, it provides a low entry-barrier for developers and users via multiple layers of abstraction that enable them to effectively cope with the complexity of the overall ecosystem. We implement several application scenarios to demonstrate these features.

L’Internet des Objets (IoT) vise à créer un eco-système global et ubiquitaire composé d’un grand nombre d’objets hétérogènes. Afin d’atteindre cette vision, le World Wide Web apparaît comme un candidat adapté pour interconnecter objets et services à la couche applicative en un Web des Objets (WoT).Cependant l’évolution actuelle du WoT produit des silos d’objets et empêche ainsi la mise en place de cette vision. De plus, même si le Web facilite la composition d’objets et services hétérogènes, les approches existantes produisent des compositions statiques incapables de s’adapter à des environnements dynamiques et des exigences évolutives. Un autre défi est à relever: permettre aux personnes d’interagir avec le vaste, évolutif et hétérogène IoT.Afin de répondre à ces limitations, nous proposons une architecture pour IoT ouvert et autogouverné, constitué de personnes et d’objets situés, en interaction avec un environnement global via des plateformes hétérogènes. Notre approche consiste de rendre les objets autonomes et d’appliquer la métaphore des réseaux sociaux afin de créer des réseaux flexibles de personnes et d’objets. Nous fondons notre approche sur les résultats issus des domaines des multi-agents et du WoT afin de produit un WoT Social.Notre proposition prend en compte les besoins d’hétérogénéité, de découverte et d’interaction flexible dans l’IoT. Elle offre également un coût minimal pour les développeurs et les utilisateurs via différentes couches d’abstraction permettant de limité la complexité de cet éco-système. Nous démontrons ces caractéristiques par la mise en oeuvre de plus scénarios applicatifs. / The Internet of Things (IoT) aims to create a global ubiquitous ecosystem composed of large numbers of heterogeneous devices. To achieve this vision, the World Wide Web is emerging as a suitable candidate to interconnect IoT devices and services at the application layer into a Web of Things (WoT).However, the WoT is evolving towards large silos of things, and thus the vision of a global ubiquitous ecosystem is not fully achieved. Furthermore, even if the WoT facilitates mashing up heterogeneous IoT devices and services, existing approaches result in static IoT mashups that cannot adapt to dynamic environments and evolving user requirements. The latter emphasizes another well-recognized challenge in the IoT, that is enabling people to interact with a vast, evolving, and heterogeneous IoT.To address the above limitations, we propose an architecture for an open and self-governed IoT ecosystem composed of people and things situated and interacting in a global environment sustained by heterogeneous platforms. Our approach is to endow things with autonomy and apply the social network metaphor to createflexible networks of people and autonomous things. We base our approach on results from multi-agent and WoT research, and we call the envisioned IoT ecosystem the Social Web of Things.Our proposal emphasizes heterogeneity, discoverability and flexible interaction in the IoT. In the same time, it provides a low entry-barrier for developers and users via multiple layers of abstraction that enable them to effectively cope with the complexity of the overall ecosystem. We implement several application scenarios to demonstrate these features.

Published methods for distributed information retrieval generally rely on cooperation from search servers. But most real servers, particularly the tens of thousands available on the Web, are not engineered for such cooperation. This means that the majority of methods proposed, and evaluated in simulated environments of homogeneous cooperating servers, are never applied in practice. ¶ This thesis introduces new methods for server selection and results merging. The methods do not require search servers to cooperate, yet are as effective as the best methods which do. Two large experiments evaluate the new methods against many previously published methods. In contrast to previous experiments they simulate a Web-like environment, where servers employ varied retrieval algorithms and tend not to sub-partition documents from a single source. ¶ The server selection experiment uses pages from 956 real Web servers, three different retrieval systems and TREC ad hoc topics. Results show that a broker using queries to sample servers’ documents can perform selection over non-cooperating servers without loss of effectiveness. However, using the same queries to estimate the effectiveness of servers, in order to favour servers with high quality retrieval systems, did not consistently improve selection effectiveness. ¶ The results merging experiment uses documents from five TREC sub-collections, five different retrieval systems and TREC ad hoc topics. Results show that a broker using a reference set of collection statistics, rather than relying on cooperation to collate true statistics, can perform merging without loss of effectiveness. Since application of the reference statistics method requires that the broker download the documents to be merged, experiments were also conducted on effective merging based on partial documents. The new ranking method developed was not highly effective on partial documents, but showed some promise on fully downloaded documents. ¶ Using the new methods, an effective search broker can be built, capable of addressing any given set of available search servers, without their cooperation.

Usability of E-government Taipei City Web Accessibility for the Visually Impaired Persons (Blind) By Yi Yee Goh This is an empirical research on e-government web accessibility exclusively for visual impaired persons, in particular for blind people in Taipei, Taiwan. Universal access is an important telecommunication concept in the information age, aiming to eliminate the digital divide. Persons with disabilities are one of the most disadvantaged groups that suffer from the digital divide. Web accessibility for this group therefore is important in the discussion of universal access. Although there has been a growing concern in related studies in the fields of web technologies, policies and end users, still, the difficulties for disabled persons, especially for visually impaired persons, remains. Narrowing down the focus to the usability of web content, with the evaluation tools of the International Web Accessibility guidelines on Web design, this paper suggests what the web designers of e-government city websites, should attend to when designing Web pages which in turn could be presented as a model for the other websites. The purpose of the present study is to determine the implementation of the guidelines to web content and what criteria might be missing from the international guidelines when websites are designed for Taiwanese Internet users. Keywords: Web accessibility

It is desirable that SOAP performs efficiently in environments where there are a large number of transactions. However, SOAP is based on XML and therefore inherits XML's disadvantage of having voluminous messages. Firstly, the performance of different SOAP bindings is investigated. A benchmark of different SOAP bindings in wireless environments demonstrates the unsuitability of HTTP and TCP bindings in limited bandwidth environments. UDP is recommended as an alternative transport protocol for SOAP. Secondly, the thesis examines the use of multicast in reducing the traffic caused by SOAP messages in low bandwidth environments to deal with challenges described. A novel SOAP-level multicast protocol based on the similarity of SOAP messages, called SMP (Similarity-based SOAP Multicast Protocol), is proposed. In particular, issues of traffic, network optimization, response time and scalability are investigated. Lastly, two extensions of SMP are proposed to further improve the performance of SMP. SMP's extensions are two algorithms, greedy and incremental tc-SMP, for traffic-constrained similarity-based SOAP multicast. Tc-SMP optimizes network traffic by building its own spanning trees instead of using the one built by traditional methods, such as Dijkstra's algorithm. A new client is added to a tc-SMP tree through an existing tc-SMP node that causes minimal additional traffic for that connection. Detailed analytical models and experimental evaluations of the proposed methods demonstrate that combining SOAP messages of similar content and multicasting them as aggregated messages can significantly lower total network traffic. These improvements are advantageous for Web service applications that involve a high number of simultaneous similar transactions such as stock quotes, weather and sport event reports.

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