En quant a l'última capacitat, la d'aprenentatge, li permet a l'agent refinar, utilitzant la seua pròpia experiència, aquells paràmetres que controlen el seu comportament, fins a l'extrem de ser capaç d'aprendre noves formes de comportar-se, nous comportaments a afegir a aquells especificats pel dissenyador. Tal com s'ha comentat prèviament, estes capacitats que conformen l'habilitat de meta-raonar s'han dut a terme en l'arquitectura d'agent ARTIS. Per eixe motiu, s'han estés els diferents

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... s d'eixa arquitectura que permeten l'aproximació a esta des de diferents nivells d'abstracció: model formal (definició des d'un nivell abstracte), model d'usuari (definició des del nivell del dissenyador d'agents ARTIS) i model de sistema (definició des del nivell directament executable). XI Abstract Over the last few years, the agent/multi-agent system paradigm is one of the most relevant computing models. It has produced a lot of specific research and applications. The objective of this computational model is to build systems that will face situations showing some human being features, such as intelligence, reactivity, pro-activity, . . . . XIII detection of significant situations is an essential capability, because without it the adaption is meaningless. Regarding the capability to adapt its behaviour, the agent will have several behaviours, being able to activate, at each moment, the proper one to its situation. The following three concepts are defined as variable ones to allow the agent to adapt its reasoning process taking into account its temporal restrictions: Reactivity: This concept is a basic feature of an agent. As it has been commented, the new approach presented here is to consider this concept as variable, defining a Reactivity Degree. This degree allows the agent to behave as more reactive or more deliberative according to it. Introspection: Generic Psychology distinguishes between extrospection and introspection as observation methods. The first one is based on the sense-derived contents analysis. The second one is based on the contents of the awareness of the individual itself. In a similar way, the present work raises this distinction when studying the agent's deliberation process. This work distinguishes between the deliberation motivated as an answer to environment changes and the deliberation about the agent's own objectives (according to its proactivity). In this way, the Introspection Degree is introduced as a value between 0 and 1 indicating the split between the process time dedicated to attend to environment changes and the process time dedicated to deliberate, to the introspection. As the introspection degree's value gets closer to 0, the agent becomes more sensitive to environment changes, whilst as the introspection degree's value gets closer to 1, the agent becomes more self-centered (more introspective). Concentration: This concept is defined, from Generic Psychology point of view, as the capacity of focusing on some specific stimuli, avoiding the ones not related to them, so that the attention is focalized and the reflection is optimized. On a similar way, Generic Psychology considers the attention XIV concept as the selective concentration of the mental activity that implies an increase of the efficiency over an specific task, as well as a perception and cognition inhibition of the rest of activities. So, the purpose of this capability to adapt the reasoning process is to apply the preceding three concepts to the agent architecture. Thus, one way to increase the efficiency of the agent in the use of the process time is to be able to focus such process; that is, to reduce the field of its reasoning process to use the available process time to what is relevant to each situation (to modify the agent's concentration). In this way, an attention focus is defined as a subset of the agent's believes that are significant in an specific situation. As the concept of concentration presents, these believes subsets will be used to optimize the reasoning (and meta-reasoning) process by means of prioritizing the reasoning about the active attention focus or focuses. The focalization mechanism does not have to be reduced to only one focus, but there can exist several attention focus at the same time, each one with a different attention degree (according to the relative importance of this focus with the other active focuses). Regarding to the last capability, learning, it must allow the agent to refine, using its own experience, its behaviour parameters. The agent should be even able to learn new ways of behaving to add to the ones specified by the designer. As it has been commented before, these capabilities forming the metareasoning ability have been carried out in the ARTIS agent architecture. To make it so, all the different models of such architecture (corresponding to different abstraction levels) have been extended: formal model (abstract level definition), user model (definition from the ARTIS agent designer's level) and system model (definition from the directly executable level). XV Agradecimientos Ha sido un largo camino para llegar hasta aquí. Un camino que comenzó con seis proyectos finales de carrera, seis proyectos de los que dos (que más bien eran uno) fueron la semilla de lo que ahora es esta tesis. Mi primer agradecimiento por tanto debe ir para aquellos que comenzaron conmigo el camino, pero en especial para Toni, aquel que compartió conmigo aquel proyecto final de carrera y se apartó del camino (de Vera). Hay, sin embargo, dos compañeros (Miguel y Vicente) que sí que siguieron conmigo todo el camino, desde aquellos días, y sin los cuales tampoco se habría llegado a este punto, pues parte de lo que aquí hay presentado se germinó en esas reuniones entre los tres en las que, divirtiéndonos bastante siempre, podíamos acabar rompiendolo todo por enésima vez. A Nacho, por mantener el fuerte durante el tiempo en el que yo perdí el camino. Al grupo original de Testeo de Red del C-18, y a su versión actual del 205, a los que quedan, a los que se fueron y a los nuevos. A mis directores, Vicente y Andrés, al primero porque siempre ha estado delante de mí en el camino, y al segundo porque se incorporó al camino un poco después que yo, pero ha acabado guiándome para llegar al final. Y en general, al resto del GT I − IA por construir entre todos un entorno en el que resulta agradable trabajar A Pili y a Jose, por su concentración, atención, introspección y reflexión. A mis padres, porque sin ellos no habría camino. Porúltimo, a todos aquellos que me han acompañado en mis diferentes estados deánimo, cuando esperaba a que me visitara la inspiración o la invitaba a quedarse y tomar algo, entre los que están Bruce Springsteen, Van XVII Morrison, Aaron Neville, Melissa Etheridge, y tantos y tantos otros. XVIII