Enrico Fischetti

C-calculus: An elementary approach to some problems in pattern recognition

Abstract This work utilizes the concept of “Composite set” ( C -set) and of the related C -calculus to study some standard problems of pattern analysis and general processing of signals. After some basic definitions and notations about composite sets are briefly stipulated, it is shown how a family of C -sets can be associated with a digitized picture. Each element in the family conveys partial information about the picture itself, yet it is possible to combine the various contributions from each C -set in such a way as to completely retrieve the image. Conditions that guarantee such “convergence” are theoretically investigated: the cases of nonconvergence are also proved to be of some interest. C -calculus is concretely applied to the extraction of significant regions in a digitized picture, of contours, etc. An application to texture discrimination and analysis is also outlined.

A hybrid context aware system for tourist guidance based on collaborative filtering

In the area of ambient intelligence there is a need to address user needs according with context features. Recently, the synergy between context aware computing and collaborative filtering is leading to enhance recommender systems with capabilities always nearer to user needs. Specifically, in the domain of tourism it is useful to proactively suggest right sets of attractive locations, events and so on. This work defines a context aware recommender system aimed at suggesting pertinent points of interest (POIs) to tourists. In particular, the approach is strongly based on the synergy between soft computing and data mining techniques. The general framework integrates user profiles, history of social networking and POIs data. Then by defining collaborative filtering approach on the history meaningful POIs are extracted. Indeed, soft computing techniques are mainly applied in order to support activity of unsupervised users and POIs classification. On the other hand, data mining techniques are exploited in order to extract rules able to associate user profile and context features with an eligible set of recommendable POIs. Experimental results show performance in terms of recommendations accuracy.

A Fuzzy-Based Approach to Stereotype Selection in Hypermedia

This paper presents a stereotype-based user model for adaptive hypermedia systems. We use a suitable algebraic fuzzy structure which can adequately reflect some features of the user in the model, and apply this model to adapt the navigation and the content of hypermedia nodes to the users needs. The model includes temporal representations of the user and approximates every real user by a set of stereotypes, from which the one realizing the best approximation can always be extracted. The set of stereotypes is the support set of the structure and the operations defined therein may be supplied with adequate semantics which allow for the selection of the stereotype.

Type-2 fuzzy decision making by means of a BL-algebra

In this paper a new method that formalizes fuzzy-based Decision Making problems by means of type-2 fuzzy sets is illustrated. The approach is based on a BL-algebra defined on these sets. This method is then compared to well-known fuzzy-based methods, namely Bellman-Zadehs, Yagers and Baldwins. The results achieved by our algorithm are similar and the linguistic presentation offers the advantage of making them more readable.

An Algebraic Tool for Classification in Fuzzy Environments

This paper illustrates the behavior of a commutative l-monoid, endowed with a suitable operation of composition, as regards the problem of classification with fuzzy attributes. The concepts of relevance and similarity are introduced, then a mechanism for weighing the attributes is shown. Finally, a case study concerning graphology is illustrated in

An application of C-calculus to texture analysis: C-transforms

Abstract A method for the analysis and discrimination of textures, based on C-calculus, is proposed. The concepts of C-space and C-transform of a digitized signal are introduced as simple tools, well suited to the visualization of the filtering properties of C-calculus: C-filters are thus also defined and the “natural” role they seem to play in problems concerning textures is investigated in some practical instances. In particular, C-transforms of some sample textures are provided and texture classification in C-space is performed. Discrimination of objects against textural background is obtained by C-filtering, in an inherently parallel fashion. The philosophy involved in this approach is finally briefly discussed in a comparison with some extant methods.

Fuzzy management of user actions during hypermedia navigation

Abstract The recent dramatic advances in the field of multimedia systems has made pacticable the development of an Intelligent Tutoring Multimedia (ITM). In these systems are present hypertextual structures that belongs to the class hypermedia systems. ITM development involves the definition of a suitable navigation model in addition to the other modules of an Intelligent Tutoring System (ITS), i.e. Database module, User module, Interface module, Teaching module. The navigation module receives as inputs the state of the system and the users current assessment and tries to optimize the fruition of the knowledge base. Moreover, this module is responsible for managing the effects of disorientation and cognitive overhead. In this paper we deal essentially with four topics: 1. (i) to define a fuzzy-based user model able to manage adequately the users cognitive state, the orientation, and the cognitive overhead; 2. (ii) to introduce fuzzy tools within the navigation module in order to carry out moves on the grounds of meaningful data; 3. (iii) to define a set of functions that can dynamically infer new states concerning users interests; 4. (iv) to classify the hypermedia actions according to their semantics.

Linguistic resources and fuzzy algebra in adaptive hypermedia systems

In this paper we formalize the representation and management of fuzzy hypermedia, linguistic resource and psycho-cognitive profile of the user by describing a consistent fuzzy-based approach to user profiling. Our model uses a correspondence between the content of information in the hypermedia domain and representation of the users. The stereotype users and the real users are represented by type-2 fuzzy sets. The domain of the latter is the set of nodes of the hypertext whereas the range are the terms of a t-uple of linguistic variables used in the definition of the users’s features. Keeping in mind the initial representation of the user, the current state and the choices done by him/her during the navigation in the hypermedia, the user model dynamically updates the representation of the real users, realizing full adaptivity with respect both to the presentation and to the navigation. The adaptivity function is constructed by means of a commutative monoid, whose support set is just the set of stereotypes.