Paolo Coppola

The Context-Aware Browser

The typical scenario of a user seeking information on the Web requires significant effort to get the desired information. In a world where information is essential, it can be crucial for users to get the desired information quickly even when they are away from their desktop computers. The Context-Aware Browser for mobile devices senses the surrounding environment, infers the users current context, and proactively searches for and activates relevant Web documents and applications.

Typing lambda terms in elementary logic with linear constraints

We present a type inference algorithm for λ-terms in Elementary Affine Logic using linear constraints. We prove that the algorithm is correct and complete.

Elementary Affine Logic and the Call-by-Value Lambda Calculus

The so-called light logics [1,2,3] have been introduced as logical systems enjoying quite remarkable normalization properties. Designing a type assignment system for pure lambda calculus from these logics, however, is problematic, as discussed in [4]. In this paper we show that shifting from usual call-by-name to call-by-value lambda calculus allows regaining strong connections with the underlying logic. This will be done in the context of Elementary Affine Logic (EAL), designing a type system in natural deduction style assigning EAL formulae to lambda terms.

AI Techniques in a Context-Aware Ubiquitous Environment

Nowadays, the mobile computing paradigm and the widespread diffusion of mobile devices are quickly changing and replacing many common assumptions about software architectures and interaction/communication models. The environment, in particular, or more generally, the so-called user context is claiming a central role in everyday’s use of cellular phones, PDAs, etc. This is due to the huge amount of data “suggested” by the surrounding environment that can be helpful in many common tasks. For instance, the current context can help a search engine to refine the set of results in a useful way, providing the user with a more suitable and exploitable information. Moreover, we can take full advantage of this new data source by “pushing” active contents towards mobile devices, empowering the latter with new features (e.g., applications) that can allow the user to fruitfully interact with the current context. Following this vision, mobile devices become dynamic self-adapting tools, according to the user needs and the possibilities offered by the environment. The present work proposes MoBe: an approach for providing a basic infrastructure for pervasive context-aware applications on mobile devices, in which AI techniques (namely a principled combination of rule-based systems, Bayesian networks and ontologies) are applied to context inference. The aim is to devise a general inferential framework to make easier the development of context-aware applications by integrating the information coming from physical and logical sensors (e.g., position, agenda) and reasoning about this information in order to infer new and more abstract contexts.

Optimizing optimal reduction: A type inference algorithm for elementary affine logic

We propose a type inference algorithm for lambda terms in elementary affine logic (EAL). The algorithm decorates the syntax tree of a simple typed lambda term and collects a set of linear constraints. The result is a parametric elementary type that can be instantiated with any solution of the set of collected constraints.We point out that the typeability of lambda terms in EAL has a practical counterpart, since it is possible to reduce any EAL-typeable lambda terms with the Lampings abstract algorithm obtaining a substantial increase of performances.We show how to apply the same techniques to obtain decorations of intuitionistic proofs into linear logic proofs.

The concept of relevance in mobile and ubiquitous information access

We discuss how the wireless-mobile revolution will change the notion of relevance in information retrieval. We distinguish between classical relevance (e-relevance) and relevance for wireless/mobile information retrieval (w-relevance). Starting from a four-dimensional model of e-relevance previously developed by one of us, we discuss how, in an ubiquitous computing environment, much more information will be available, and how it is therefore likely that w-relevance will be more important than e-relevance to survive information overload. The similarities and differences between e-relevance and w-relevance are described, and we show that there are more differences than one might think at first. We specifically analyze the role that beyond-topical criteria have in the w-relevance case, and we show some examples to clarify and support our position.

Light Logics and the Call-by-Value Lambda Calculus

The so-called light logics have been introduced as logical systems enjoying quite remarkable normalization properties. Designing a type assignment system for pure lambda calculus from these logics, however, is problematic. In this paper we show that shifting from usual call-by-name to call-by-value lambda calculus allows regaining strong connections with the underlying logic. This will be done in the context of Elementary Affine Logic (EAL), designing a type system in natural deduction style assigning EAL formulae to lambda terms.

Animated products as a navigation aid for e-commerce

Virtual Reality (VR) interfaces to e-commerce sites promise to make the e-shopping experience more natural, attractive, and fun for buyers. In this paper, we first briefly introduce the navigation problem, then we propose a novel navigation aid to help customers of VR stores in finding products. The proposed aid is based on 3D animated products which guide the customer towards her/his destination, and can also take into account the merchandising strategy of the store.

Light Logics and Optimal Reduction: Completeness and Complexity

Typing of lambda-terms in elementary and light affine logic (EAL , LAL resp.) has been studied for two different reasons: on the one hand the evaluation of typed terms using LAL (EAL resp.) proof-nets admits a guaranteed polynomial (elementary, resp.) bound; on the other hand these terms can also be evaluated by optimal reduction using the abstract version of Lampings algorithm. The first reduction is global while the second one is local and asynchronous. We prove that for LAL (EAL resp.) typed terms, Lampings abstract algorithm also admits a polynomial (elementary, resp.) bound. We also show its soundness and completeness (for EAL and LAL with type fixpoints), by using a simple geometry of interaction model (context semantics).

Optimal) duplication is not elementary recursive

In 1998, Asperti and Mairson proved that the cost of reducing a λ-term using an optimal λ-reducer (a la Levy) cannot be bound by any elementary function in the number of shared-beta steps. We prove in this paper that an analogous result holds for Lampings abstract algorithm. That is, there is no elementary function in the number of shared beta steps bounding the number of duplication steps of the optimal reducer. This theorem vindicates the oracle of Lampings algorithm as the culprit for the negative result of Asperti and Mairson. The result is obtained using as a technical tool Elementary Affine Logic.