Net4voice è un progetto attraverso il quale si vogliono sperimentare nuove modalità di apprendimento che possano agevolare la diffusione dei patrimoni informativi, rendendoli universalmente accessibili. Le tecnologie di riconoscimento vocale sono rivolte innanzitutto agli studenti diversamente abili, in particolare a coloro che hanno difficoltà a prendere appunti oppure che hanno problemi di udito, nonché agli studenti stranieri, realtà sempre più presente nelle scuole italiane, che stanno imparando una seconda lingua o che seguono le lezioni in una lingua diversa dalla loro.

AbstrAct The increasing diffusion of wireless portable devices and the emergence of mobile ad hoc networks promote anytime and anywhere opportunistic resource sharing. However, the fear of exposure to risky interactions is currently limiting the widespread uptake of ad hoc collaborations. This chapter introduces the challenge of identifying and validating novel security models/systems for securing ad hoc collaborations, by taking into account the high unpredictability, heterogeneity, and dynamicity of envisioned wireless environments. We claim that the concept of trust management should become a primary engineering design principle, to associate with the subsequent trust refinement into effective authorization policies, thus calling for original and innovative access control models. The chapter overviews the state-of-the-art solutions for trust management and access control in wireless environments by pointing out both the need for their tight integration and the related emerging design guidelines, that is, exploitation of context awareness and adoption of semantic technologies.

Pervasive user mobility, wireless connectivity and the widespread diffusion of portable devices raise new challenges for ubiquitous service provisioning. An emerging architecture solution in the wireless Internet is based on mobile proxies (implemented as mobile agent-based middleware components) over the fixed network that follow the movements and act on behalf of the limited wireless clients. It is crucial that mobile proxies have full visibility of their context, i.e., the set of available and relevant resources, depending on access control rules, client location, user preferences, privacy requirements, terminal characteristics, and current state of hosting environments. The paper presents the design and implementation of a context-centric security middleware, called UbiCOSM, for MA-based service provisioning in pervasive computing. UbiCOSM dynamically determines the contexts of mobile proxies, and effectively rules the access to them, by taking into account different types of metadata (user profiles and authorization policies), expressed at a high level of abstraction and cleanly separated from the service logic. The paper also shows the functioning of UbiCOSM in the design and the development of a mobile context-centric airport business assistant.

The growing diffusion of portable devices with wireless connectivity and the integration of telecommunication systems and the Internet enable users to benefit from anytime and anywhere impromptu collaboration. Security is crucial to ensure secure sharing of information, but calls for novel solutions capable of establishing trust relationships on-the-fly among previously unknown entities. Traditional trust solutions seem to be inappropriate in dynamic mobile environments. They typically rely on centralised trust certification authorities and assign to entities levels of trust that depend on static entity attributes, such as entity identity or role. However, entity identities/roles are often either not sufficiently informative or too limited to take adequate collaborative decisions. This paper presents a novel trust model that rules the assignment of trust to entities based on various dynamic context information, e.g., user/device location, device properties, user needs, local operating conditions. As key features, this model allows to determine, to associate and to adapt entity levels of trust depending on the contexts where users operate and users acquire/lose a level of trust when entering/leaving a specific context. The proposed model facilitates the update of trust relationships as relevant changes in context information occur. The paper also shows the implementation of the proposed model in the COMITY framework that provides support facilities for defining and enforcing context-based trust policies.

Wireless connectivity and the widespread diffusion of portable devices raise new challenges for ubiquitous service provisioning. Mobility of users causes frequent and unpredictable changes in user location and in consequently available resources. Access control to resources is crucial to leverage the provision of ubiquitous services and calls for novel solutions based on various context information, e.g., user location, device properties, user needs, local resource visibility. This work presents a novel access control model that proposes the adoption of context as a first-class design principle to rule access to resources. The paper proposes a context-centric access control middleware, called UbiCOSM, that dynamically determines the contexts of mobile users and effectively rules the access to them, by taking into account different types of metadata: user profiles and system/user-level authorization policies. The paper also presents a context-dependent movie-info service to evaluate the functioning of UbiCOSM.

Mobile Agent (MA) technology raises significant security concerns and requires a thorough security framework with a wide range of strategies and mechanisms for the protection of both agent platform and mobile agents against possibly malicious reciprocal behavior. The security infrastructure should have the ability to flexibly and dynamically offer different solutions to achieve different qualities of security service depending on application requirements. The chapter presents the security threats that typically arise in MA applications and describes the proposed currently available countermeasures to protect both nodes and mobile agents. In addition, the chapter surveys the state-of-the-art research activities about integrated security supports in MA systems and identifies open research issues and on-going research work. 1 Security: a Missing Link for Mobile Agents Acceptance The convergence of the Internet with wireless communications have raised new challenges in the support of user and terminal mobility, in facing heterogeneity, and in adapting to the dynamic changes in the network infrastructure [1]. The new scenario seems a suitable application area for computing paradigms that exploit the notion of code mobility, defined as the capability to dynamically change the binding between software components and their location of execution [2]. As mobile networks gain widespread acceptance and ubiquitous environments start to emerge, the ability to change the locations where applications can execute becomes an increasingly important requirement. For example, we can think to heterogeneous and resource-limited portable devices that can benefit from the possibility to download on-demand device-specific software components and discard them when no longer needed.

User/terminal mobility during service provisioning and high heterogeneity of wireless portable devices identify novel challenges for service delivery in ubiquitous pervasive environments. An emerging architecture solution in the wireless Internet is to have middleware components (mobile proxies) over the fixed network that follow the movements and act on behalf of the limited wireless clients. It is crucial that mobile proxies have full visibility of their context, i.e., the set of available and relevant resources depending on access control rules, client location, user preferences, privacy requirements, terminal characteristics, and current state of hosting environments. The paper presents the design and implementation of a context-centric access control middleware, called COSMOS, for the wireless Internet. COSMOS dynamically determines the contexts of mobile proxies, and effectively rules the access to them, by taking into account different types of metadata (user profiles and system/user-level authorization policies), expressed at a high level of abstraction and cleanly separated from the service logic. The paper also shows how COSMOS facilitates the development of articulated access control strategies in the case study of a context-dependent movie-info service deployed over IEEE 802.11 network localities.

The increasing diffusion of wireless portable devices and the emergence of mobile ad hoc networks promote anytime and anywhere opportunistic resource sharing. However, the fear of exposure to risky interactions is currently limiting the widespread uptake of ad hoc collaborations. This chapter introduces the challenge of identifying and validating novel security models/systems for securing ad hoc collaborations, by taking into account the high unpredictability, heterogeneity, and dynamicity of envisioned wireless environments. We claim that the concept of trust management should become a primary engineering design principle, to associate with the subsequent trust refinement into effective authorization policies, thus calling for original and innovative access control models. The chapter overviews the state-of-theart solutions for trust management and access control in wireless environments by pointing out both the need for their tight integration and the related emerging design guidelines, that is, exploitation of context awareness and adoption of semantic technologies.

Pervasive user mobility, wireless connectivity and the widespread diffusion of portable devices raise new challenges for ubiquitous service provisioning. In particular, mobility of users/devices causes frequent and unpredictable changes in physical user location and in consequently available resources and services. Users can also change portable access devices, with different capabilities, even at runtime and during the same service session, thus forcing us to consider very dynamic aspects even due to client heterogeneity. Access control to resources is crucial to leverage the provision of ubiquitous services and calls for novel solutions based on various context information, e.g., user/device location, device properties, user needs, local resource visibility. This work presents a novel access control model built upon the concept of context as the first-class design principle to rule access to resources. As key features, this model allows to associate access control permissions with contexts where users operate and users acquire/lose their permissions when entering/leaving a specific context. Unlike traditional access control solutions where user identity/role triggers policy evaluation when requesting resource access, this model exploits the user context to fully determine the set of available permissions. In addition, the proposed model allows to express context-based access control policies at a high level of abstraction cleanly separate from service logic implementation, thus promoting dynamic policy modification with no impact on the service code. The paper shows the implementation of the proposed model in the UbiCOSM framework and presents a mobile office service provisioning scenario.