http://hdl.handle.net/2117/3973 2013-05-24T14:31:40Z http://hdl.handle.net/2117/16708 Title: Specialization in i* strategic rationale diagrams Authors: López Cuesta, Lidia; Franch Gutiérrez, Javier; Marco Gómez, Jordi Abstract: The specialization relationship is offered by the i* modeling language through the is-a construct defined over actors (a subactor is-a superactor). Although the overall meaning of this construct is highly intuitive, its semantics of strategic rationale (SR) diagrams is not defined. In this report we provide a formal definition of the specialization relationship at the level of i* SR diagrams. We root our proposal over existing work in conceptual modeling in general, and object-orientation in particular. Also, we use the results of a survey conducted in the i* community that provides some hints about what i* modelers expect from specialization. As a consequence of this twofold analysis, we identify, define and specify two specialization operations, extension and refinement, that can be applied over SR diagrams. Correctness conditions for them are also clearly stated. The result of our work is a formal proposal of specialization for i* that allows its use in a well-defined manner. 2012-10-10T15:23:35Z http://hdl.handle.net/2117/15716 Title: Non-functional requirements in software architecture practice Authors: Ameller, David; Ayala Martínez, Claudia Patricia; Cabot Sagrera, Jordi; Franch Gutiérrez, Javier Abstract: Dealing with non-functional requirements (NFRs) has posed a challenge onto software engineers for many years. Over the years, many methods and techniques have been proposed to improve their elicitation, documentation, and validation. Knowing more about the state of the practice on these topics may benefit both practitioners’ and researchers’ daily work. A few empirical studies have been conducted in the past, but none under the perspective of software architects, in spite of the great influence that NFRs have on daily architects’ practices. This paper presents some of the findings of an empirical study based on 13 interviews with software architects. It addresses questions such as: who decides the NFRs, what types of NFRs matter to architects, how are NFRs documented, and how are NFRs validated. The results are contextualized with existing previous work. 2012-04-10T11:50:02Z http://hdl.handle.net/2117/15664 Title: Unsupervised ensemble minority clustering Authors: González Pellicer, Edgar; Turmo Borras, Jorge Abstract: Cluster a alysis lies at the core of most unsupervised learning tasks. However, the majority of clustering algorithms depend on the all-in assumption, in which all objects belong to some cluster, and perform poorly on minority clustering tasks, in which a small fraction of signal data stands against a majority of noise. The approaches proposed so far for minority clustering are supervised: they require the number and distribution of the foreground and background clusters. In supervised learning and all-in clustering, combination methods have been successfully applied to obtain distribution-free learners, even from the output of weak individual algorithms. In this report, we present a novel ensemble minority clustering algorithm, Ewocs, suitable for weak clustering combination, and provide a theoretical proof of its properties under a loose set of constraints. The validity of the assumptions used in the proof is empirically assessed using a collection of synthetic datasets. 2012-03-26T13:51:19Z http://hdl.handle.net/2117/14848 Title: WeSSQoS: a configurable SOA system for quality-aware web service selection Authors: Cabrera Bejar, Oscar; Oriol Hilari, Marc; Franch Gutiérrez, Javier; López Cuesta, Lidia; Marco Gómez, Jordi; Fragoso, Olivia; Santaolaya, René Abstract: Web Services (WS) have become one the most used technologies nowadays in software systems. Among the challenges when integrating WS in a given system, requirements-driven selection occupies a prominent place. A comprehensive selection process needs to check compliance of Non-Functional Requirements (NFR), which can be assessed by analysing WS Quality of Service (QoS). In this paper, we describe the WeSSQoS system that aims at ranking available WS based on the comparison of their QoS and the stated NFRs. WeSSQoS is designed as an open service-oriented architecture that hosts a configurable portfolio of normalization and ranking algorithms that can be selected by the engineer when starting a selection process. WS’ QoS can be obtained either from a static, WSDL-like description, or computed dynamically through monitoring techniques. WeSSQoS is designed to work over multiple WS repositories and QoS sources. The impact of having a portfolio of different normalization and ranking algorithms is illustrated with an example. 2012-01-27T12:08:36Z http://hdl.handle.net/2117/14824 Title: Frequent sets, sequences and taxonomies: new efficient algorithmic proposals Authors: Baixeries i Juvillà, Jaume; Casas Garriga, Gemma; Balcázar Navarro, José Luis Abstract: We describe efficient algorithmic proposals to approach three fundamental problems in data mining: association rules, episodes in sequences, and generalized association rules over hierarchical taxonomies. The association rule discovery problem aims at identifying frequent itemsets in a database and then forming conditional implication rules among them. For this association task, we will introduce a new algorithmic proposal to reduce substantially the number of processed transactions. The resulting algorithm, called Ready-and-Go, is used to discover frequent sets efficiently. Then, for the discovery of patterns in sequences of events in ordered collections of data, we propose to apply the appropiate variant of that algorithm, and additionally we introduce a new framework for the formalization of the concept of intereseting episodes. Finally, we adapt our algorithm to the generalization of the frequent sets problem where data comes organized in taxonomic hierarchies, and here additionally we contribute with a new heuristic that, under certain natural conditions, improves the performance. 2012-01-26T10:47:30Z http://hdl.handle.net/2117/14274 Title: Word sense ranking based on semantic similarity and graph entropy Authors: Sousa Lopes, João; Álvarez Napagao, Sergio; Vázquez Salceda, Javier Abstract: In this paper we propose a system for the recommendation of tagged pictures obtained from the Web. The system, driven by user feedback, executes an abductive reasoning (based on WordNet synset semantic relations) that is able to iteratively lead to new concepts which progressively represent the cognitive creative user state. Furthermore we design a selection mechanism to pick the most relevant abductive inferences by mixing a topological graph analysis together with a semantic similitude measure. 2011-12-19T14:41:49Z http://hdl.handle.net/2117/14269 Title: USE: a multi-agent user-driven recommendation system for semantic knowledge extraction Authors: Lopes, João Sousa; Álvarez Napagao, Sergio; Confalonieri, Roberto; Vázquez Salceda, Javier Abstract: Semiotics is a field where research on Computer Science methodologies has focused, mainly concerning Syntax and Semantics. These methodologies, however, are lacking of some flexibility for the continuously evolving web community, in which the knowledge is classified with tags rather than with ontologies. In this paper we propose a multi-agent system for the recommendation of tagged pictures obtained from mainstream Web applications. The agents in this system execute a hybrid reasoning based on WordNet and Markov chains that is able, driven by user feedback, to iteratively disambiguate the semantics of the picture tags and thus to generate knowledge from the, a priori arbitrary, information available in the Internet. 2011-12-19T11:46:03Z http://hdl.handle.net/2117/14268 Title: Reasoning about abductive inferences in BDI agents Authors: Lopes, João Sousa; Álvarez Napagao, Sergio; Reis, Susana; Vázquez Salceda, Javier Abstract: The capability of a computational system to deal with unexpected, changing situations and limited perception of the environment is becoming more a more relevant, in oder to make systems flexible and more reliable. Multi-agent Systems offer a computing paradigm where properties such as autonomy, adaptability or flexibility are basic in the construction of agent-based solutions. However most of current implementations are not flexible enough to cope with important changes in the environment or information loss. In this paper we propose to introduce abductive reasoning mechanisms in BDI agents and show how such agents are able to operate with partial models of the environment. 2011-12-19T11:25:19Z http://hdl.handle.net/2117/13915 Title: Metamodelo de la especificación OSID versión 2 de OKI Authors: Rius Gavídia, M. Ángeles; Conesa Caralt, Jordi; García Barriocanal, M. Elena Abstract: En las últimas décadas dentro del ámbito del e-Learning, la investigación acerca de especificaciones y estándares relacionados con contenidos digitales ha evolucionado notablemente. Aunque se han multiplicado el número de plataformas de sistemas de aprendizaje, las especificaciones y estándares relacionados con procesos para entornos educativos no han tenido la misma suerte. La especificación Open Service Interface Definition (OSI) de Open Knowledge Initiative (OKI) propone un conjunto de interfaces de servicios web dirigidos a entornos de enseñanza superior con el objetivo de conseguir interoperabilidad entre aplicaciones. Sin embargo esta especificación no ha sido demasiado utilizada, posiblemente por falta de un mapa conceptual que facilite su compresión y promueva su uso. En este trabajo se describe un metamodelo de la especificación OKI-OSID mediante UML y un conjunto de reglas. También se presentan una lista de las limitaciones detectadas tras el estudio de dicha especificación. 2011-11-15T17:17:24Z http://hdl.handle.net/2117/13836 Title: Aprendizaje y asistencia virtual en red Authors: Fuentes Fort, Maria; González Bermúdez, Meritxell; Guardiola Garcia, Marta; Jofre Roca, Lluís; Romeu Robert, Jordi; Vallverdú Bayés, Francesc Abstract: Favorecer el uso de las Tecnologías de Información y la Comunicación (TIC) en entornos educativos puede abarcar varios aspectos del proceso de aprendizaje. La incorporación de TICs en las aulas contribuye, por un lado a reducir la brecha digital tanto de profesores como alumnos y por el otro, debiera ayudar a mejorar la metodología educativa. Sin duda las TICs pueden ser de gran ayuda para llegar a alcanzar los objetivos pedagógicos. En concreto, este estudio tenía por objetivo analizar la manera de incorporar tecnologías de la voz y el procesamiento del lenguaje natural para mejorar el proceso de aprendizaje de la lengua. Para identificar cuales son las características de éste proceso, que aspectos se verán modificados con la incorporación de estas tecnologías y como afectaran las modificaciones a cada aspecto del proceso, en Diciembre de 2010 se organizó una jornada que reunió a distintos sectores sociales directamente involucrados con el ámbito a tratar. Como resultado de ésta jornada, en Abril de 2011, se llevará a cabo una prueba piloto en que se incorporará las tecnologías propuestas en el aprendizaje de inglés y ya se ha empezado a definir un proyecto a medio plazo para buscar financiamiento a nivel estatal o europeo. 2011-11-09T14:34:16Z http://hdl.handle.net/2117/12953 Title: On the proper intervalization of colored caterpillar trees Authors: Álvarez Faura, M. del Carme; Serna Iglesias, María José Abstract: This paper studies the computational complexity of the Proper interval colored graph problem (picg), when the input graph is a colored caterpillar, parameterized by hair length. In order prove our result we establish a close relationship between the picg and a graph layout problem the Proper colored layout problem (pclp). We show a dichotomy: the picg and the pclp are NP-complete for colored caterpillars of hair length ≥ 2, while both problems are in P for colored caterpillars of hair length < 2. For the hardness results we provide a reduction from the Multiprocessor Scheduling problem, while the polynomial time results follow from a characterization in terms of forbidden subgraphs. 2011-07-13T09:48:20Z http://hdl.handle.net/2117/12934 Title: Sensor field: a computational model Authors: Álvarez Faura, M. del Carme; Duch Brown, Amalia; Gabarró Vallès, Joaquim; Serna Iglesias, María José Abstract: We introduce a formal model of computation for networks of tiny artifacts, the static synchronous sensor field model (SSSF) which considers that the devices communicate through a fixed communication graph and interact with the environment through input/output data streams. We analyze the performance of SSSFs solving two sensing problems the Average Monitoring and the Alerting problems. For constant memory SSSFs we show that the set of recognized languages is contained in DSPACE(n+m) where n is the number of nodes of the communication graph and m its number of edges. Finally we explore the capabilities of SSSFs having sensing and additional non-sensing constant memory devices. 2011-07-12T10:23:04Z http://hdl.handle.net/2117/12791 Title: Detecció de fallades en un sistema de piles de combustible Authors: Escobet Canal, Antoni; Nebot Castells, M. Àngela Abstract: In this work a fault diagnosis system for non-linear plants based on fuzzy logic, called VisualBlock-FIR, is presented and applied to an energy generation system based on fuel cells. VisualBlock-FIR runs under the Simulink framework and enables early fault detection and identification. During fault detection, the fault diagnosis system should recognize that the system is not working properly. During fault identification, it should conclude which type of failure has occurred. The diagnosis results for some of the most frequent faults in fuel cell systems are presented. 2011-06-17T16:15:46Z http://hdl.handle.net/2117/12369 Title: Development of the conceptual schema of the osTicket system by applying TDCM Authors: Tort Pugibet, Albert Abstract: This document reports a case study application of Test-Driven Conceptual Modeling (TDCM) in the reverse engineering development of the conceptual schema of a well-known, open-source and widely-used online support system called osTicket. 2011-04-14T14:53:50Z http://hdl.handle.net/2117/12364 Title: Quick learning of cause-effects relevant for robot action Authors: Agostini, Alejandro Gabriel; Wörgötter, Florentin; Torras, Carme Abstract: In this work we propose a new paradigm for the rapid learning of cause-effect relations relevant for task execution. Learning occurs automatically from action experiences by means of a novel constructive learning approach designed for applications where there is no previous knowledge of the task or world model, examples are provided on-line during run time, and the number of examples is small compared to the number of incoming experiences. These limitations pose obstacles for the existing constructive learning methods, where on-line learning is either not considered, a significant amount of prior knowledge has to be provided, or a large number of experiences or training streams are required. The system is implemented and evaluated in a humanoid robot platform using a decision-making framework that integrates a planner, the proposed learning mechanism, and a human teacher that supports the planner in the action selection. Results demonstrate the feasibility of the system for decision making in robotic applications. 2011-04-13T17:03:49Z