In this paper, we present an incremental clustering approach for shape annotation, which is useful when new sets of images are available over time. A semi-supervised fuzzy clustering algorithm is used to group shapes into a number of clusters. Each cluster is represented by a prototype that is manually labeled and used to annotate shapes belonging to that cluster. To capture the evolution of the image set over time, the previously discovered prototypes are added as pre-labeled objects to the current shape set and semi-supervised clustering is applied again. The proposed incremental approach is evaluated on two benchmark image datasets, which are divided into chunks of data to simulate the progressive availability of images during time.

Situation-aware service recommendation for mobile devices is aimed at proactively pushing personalized suggestions to users, presenting them unseen or unknown services. A challenging area in the field is that of recommendation schemes emerging from users' collective behavior. When we consider a mobile user, for instance, the recommendation process can be based on social events that can arise from collective positioning information. In this scenario, we discuss a collaborative multi-agent scheme for event detection, in which fuzzy representations are employed to cope with the approximation typical of implicit and aggregated information. More specifically, the first level of information processing is managed by marking agents leaving marks in the environment which are associated with users' positioning. The accumulation of marks enables a fuzzy information granulation process, managed by event agents, in which relevant events can emerge. Finally, a fuzzy inference level, managed by situation agents, deduces user situations from the underlying events.

In recommender systems, the task of automatically deriving user profiles, encoding the actual preferences of users, covers a fundamental role. In this paper, we propose a strategy for learning and updating user profiles by using fuzzy sets that reveal to be a valid tool to model the vague and imprecise nature of preferences as well as the items to be recommended. The proposed adaptation strategy resembles a competitive learning process in which the user profile is continuously updated in order to make its components as similar as possible to the description of the accessed items. On the same time a mechanism to forget outdated user preferences is proposed in order to describe changes in user interests over time. The strategy was applied on the MovieLens dataset and the obtained results show its effectiveness to learn user profiles reflecting the current preferences of users.

Recommender systems are systems capable of assisting users by quickly providing them with relevant resources according to their interests or preferences. The efficacy of a recommender system is strictly connected with the possibility of creating meaningful user profiles, including information about user preferences, interests, goals, usage data and interactive behavior. In particular, analysis of user preferences is important to predict user behaviors and make appropriate recommendations. In this paper, we present a fuzzy framework to represent, learn and update user profiles. The representation of a user profile is based on a structured model of user cognitive states, including a competence profile, a preference profile and an acquaintance profile. The strategy for deriving and updating profiles is to record the sequence of accessed resources by each user, and to update preference profiles accordingly, so as to suggest similar resources at next user accesses. The adaption of the preference profile is performed continuously, but in earlier stages it is more sensitive to updates (plastic phase) while in later stages it is less sensitive (stable phase) to allow resource recommendation. Simulation results are reported to show the effectiveness of the proposed approach.

Adaptive software systems are systems that tailor their behavior to each user on the basis of a personalization process. The efficacy of this process is strictly connected with the possibility of an automatic detection of preference profiles, through the analysis of the users' behavior during their interactions with the system. The definition of such profiles should take into account imprecision and gradedness, two features that justify the use of fuzzy sets for their representation. This paper proposes a model for representing preference profiles through fuzzy sets. The model's strategy for adapting profiles to user preferences is to record the sequence of accessed resources by each user, and to update preference profiles accordingly so as to suggest similar resources at next user accesses. Profile adaption is performed continuously, but in earlier stages it is more sensitive to updates (plastic phase) while in later stages it is less sensitive (stable phase) to allow resource suggestion. Simulation results are reported to show the effectiveness of the proposed approach.

Recommender systems attempt to predict the needs of Web users and provide them with recommendations to personalize their online experience. In this paper, we propose a neuro-fuzzy approach for the extraction of a recommendation model from usage data encoding user navigational behaviors. Such model is expressed as a set of fuzzy rules which may be exploited to provide personalized link suggestions to the users visiting a Web site. In particular, a neuro-fuzzy network is trained using information about user categories to discover a set of fuzzy rules capturing the associations between user behavior models and relevance degrees of pages to be recommended. A comparison with other recommendation approaches shows the effectiveness of the proposed neuro-fuzzy approach in finding good recommendation rules.

Computational Intelligence (CI) paradigms reveal to be potential tools to face under the Web uncertainty. In particular, CI techniques may be properly exploited to handle Web usage data and develop Web-based applications tailored on users preferences

In this paper we propose a meta-classification framework which is able to represent the accumulated experience from a base-learner in form of knowledge-base and to exploit it whenever a new task has to be tackled. Our meta-dassificr represents a particular meta-learning strategy where a single learning algorithm is employed both at base- and meta-level of learning. The proposed meta-classification framework is based on a neuro-fuzzy approach where connectionist paradigm is integrated with fuzzy logic for the management of the accumulated knowledge during the learning process. A complete experimental session is presented, in order to show the suitability of the system. Additionally, in a final experimental evaluation, we show that the obtained accuracy results are comparable with the ones obtained by another meta classification scheme presented in literature.

This paper describes a peculiar methodology for identifying and classifying the human body structures depicted in digital images. The methodology is articulated in a number of successive steps: an initial process of motion detection recognises human targets into the examined scene; subsequently, a synthetic representation of the previously detected human figures is obtained in form of skeleton, by means of a thinning operator. Finally, the pose estimation step is performed on the basis of a geometrical analysis conducted over a set of features related to the extracted skeletons. Experimental evidence of the appropriateness of the overall methodology is also presented.