Smart spaces provide information about physical environments, shared with inherently dynamic applications. This chapter introduces a novel development approach with its focus on two key properties of smart space applications: the ability to interoperate and behave in a situation-sensitive manner. Sixteen principles are defined in order to guide the development of an interoperability platform for smart spaces and on how to create applications on top of it. The interoperability platform deals with information and is agnostic with respect to ontologies, programming languages, service frameworks, and communication technologies. The interoperability platform also supports extensibility, evolvability and context based adaptation, which allows new applications to be added and to behave in a situation based manner. Agile application development is based on scenario specifications, implemented by the means of the ontology and model driven development. The approach has been applied to the development of smart personal spaces, smart indoor spaces, and smart city applications.

With the increased prevalence of advanced mobile devices (the so-called "smart" phones), interest has grown in mobile social ecosystems, where users not only access traditional Web-based social networks using their mobile devices, but are also able to use the context information provided by these devices to further enrich their interactions. In complex mobile social ecosystems of the future the heterogeneity of software platforms on constituent nodes, combined with their intrinsic distributed nature and heterogeneity of representation of data and context raises the need for middleware support for the development of mobile social applications.In this paper, we propose Yarta, a novel middleware designed for mobile social ecosystems (MSE), which takes into account the heterogeneity of both deployment nodes and available data, the intrinsic decentralized nature of mobile social applications, as well as users' privacy concerns. To validate our approach, we show how we developed two mobile social applications over Yarta, and report on both its efficiency and ease-of use by way of extensive evaluation on smart phones and laptops.

Computational trust is a central paradigm in today’s Internet as our modern society is increasingly relying upon online transactions and social networks. This is indeed leading to the introduction of various trust management systems and associated trust models, which are customized according to their target applications. However, the heterogeneity of trust models prevents exploiting the trust knowledge acquired in one context in another context although this would be beneficial for the digital, ever-connected environment. This is such an issue that this paper addresses by introducing an approach to achieve interoperability between heterogeneous trust management systems. Specifically, we define a trust meta-model that allows the rigorous specification of trust models as well as their composition. The resulting composite trust models enable heterogeneous trust management systems to interoperate transparently through mediators.

The novel scenarios enabled by emerging mobile social applications raise serious concerns regarding access control of users' contextual and social data. Given the variety of existing and upcoming social applications, it is important to provide (i) generic yet flexible policy models that combine expressivity with personalization, (ii) actual running infrastructures to en-force policy-based access control on heterogenous devices with minimal development/deployment effort, and (iii) user-interfaces to allow the easy specification of policies without dealing with the complexity of the underlying policy and data models. Toward this goal, in this paper we make three contributions. First, we present a novel policy framework for controlling access to social data in mobile applications. The framework allows the representation of expressive policies based on users' social interactions, which can be easily extended with new domain data models, while keeping policy model compatibility intact. Secondly, we demonstrate how we integrated the policy framework as part of Yarta, a middleware for managing mobile users' social ecosystems, implemented and deployed on laptops and smart phones. Third, we show the graphical policy editor provided with the policy framework to allow non-technology savvy users to easily specify and manage their access control policies.

With the increased prevalence of advanced mobile devices (the so-called “smart” phones), interest has grown in mobile social ecosystems, where users not only access traditional Web-based social networks using their mobile devices, but are also able to use the context information provided by these devices to further enrich their interactions. Owing to the large variety of platforms available for smart phones, as well as the different ways that data and context information is represented, it is natural to think of middleware solutions that the developers of these systems can use while creating their applications. In this paper, we highlight the issues which should be addressed by middleware designed for mobile social ecosystems, taking into account the heterogeneity of both deployment nodes and available data, the intrinsic distributed nature of mobile social applications, as well as users' security concerns. As part of our ongoing effort to develop this middleware, we present a comprehensive model to represent mobile social ecosystems and the interactions possible in them, and show how to exploit it in a representative scenario.

A still open issue in pervasive systems is how to effectively support the development and run-time execution of smart applications in wide-scale and open deployment scenarios. That calls for i) easy and low-cost interoperability with legacy systems/services and ii) scalability in terms of both overhead and performance results for different classes of applications with different quality requirements. In this position paper, we report the research work we are doing within an ongoing project on the exploitation of context awareness for scalability in smart environments, where interoperability is achieved at the information level via semantic technologies. In particular, the paper shows how context-aware middleware facilities can help in dynamically determining personalized views on a shared information space, implemented as coordinated repositories of Resource Description Format triples. The advantages are relevant in terms of usability (automatic discarding of unsuitable resource/service components) and overhead reduction (limitation of quality monitoring space).

Advances in wireless networks, sensors, and portable devices offer unique chances to deliver novel anytime anywhere medical services and information, thus enabling a wide range of healthcare applications, from mobile telemedicine to remote patient monitoring, from location-based medical services to emergency response. Mobile e-health has great potential to extend enterprise hospital services beyond traditional boundaries, but faces many organizational and technological challenges. In pervasive healthcare environments, characterized by user/service mobility, device heterogeneity, and wide deployment scale, a crucial issue is to discover available healthcare services taking into account the dynamic operational and environmental context of patient-healthcare operator interactions. In particular, novel discovery solutions should support interoperability in healthcare service descriptions and ensure security during the discovery process by making services discoverable by authorized users only. This article proposes a semantic-based secure discovery framework for mobile healthcare enterprise networks that exploits semantic metadata (profiles and policies) to allow flexible and secure service search/retrieval. As a key feature, our approach integrates access control functionalities within the discovery framework to provide users with filtered views on available services based on service access requirements and user security credentials.

Smart phones pose new challenges to usable security. Current means of specifying security policies or preferences for resource sharing are either woefully inadequate or too hard to use. This article presents a policy model approach toward usable security for smart phones. In particular, the approach adopts a semantic-based policy representation to help users' understanding of security policies and to better reflect what users really want. Furthermore, given the special nature of smart phones' usage, social awareness plays an important role. In this regard, the authors present propose a socially-aware policy reasoning model based on the results of a user study.

The widespread diffusion of wireless-enabled portable devices creates novel opportunities for users to share resources anywhere and anytime, but makes access control a crucial issue. User/device mobility and heterogeneity, together with network topology and conditions variability, complicate access control and call for novel solutions to dynamically adapt access decisions to the different operating conditions. Several research efforts have emerged in recent years that propose to exploit context-awareness to control access to resources based on context visibility and changes. Context-based access control requires, however, to take into account the quality of context information used to drive access decisions (QoC). Quality of context has in fact a profound impact on the correct behavior of any context-aware access control framework. Using context information with insufficient quality might increase the risk of incorrect access control decisions, thus leading to dangerous security breaches in resource sharing. In this paper we propose a QoC-aware approach to access control for anywhere, anytime resource sharing. The paper describes the design, implementation and evaluation of the Proteus policy framework, which combines two design guidelines to enable dynamic adaptation of policies depending on context changes: context-awareness with QoC guarantees and semantic technologies to allow high-level description of context/policy specification and reasoning about context/policies.

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.

Mobile phones currently represent the most pervasive technology for enabling social networking. They collect a wide range of socially meaningful data, such as address book contacts, pictures, call logs and exchanged messages. This data, however, is highly underutilized as it is managed by separate applications which are typically unaware of the user’s social setting. This “unawareness” makes the user a slave of his device instead of helping him achieve his goals or manage his everyday activities. Enhancing next generation mobile phone with socially-aware features will provide significant benefits. In this paper, we present real data collected from a user study about mobile phone usage, with the aim of providing evidence for the need of socially-aware phone applications. As a relevant example of socially-aware capability, we analyze the case of interruption management, i.e., how and why users respond to an incoming call or message by interrupting their current activity. To automate interruption management on mobile phones, we suggest the adoption of a policy-based approach to express socially-aware policies based on Semantic Web technologies.

The increasing diffusion of portable devices with wireless connectivity enables new pervasive scenarios, where users require tailored service access according to their needs, position, and execution/environment conditions (context-aware services). A crucial requirement for the context-aware service provisioning is the dynamic retrieval and interaction with local resources, i.e., resource discovery. The high degree of dynamicity and heterogeneity of mobile environments requires to rethink and/or extend traditional discovery solutions to support more intelligent service search and retrieval, personalized to user context conditions. Several research efforts have recently emerged in the field of service discovery that, based on semantic data representation and technologies, allow flexible matching between user requirements and service capabilities in open and dynamic deployment scenarios. This paper proposes a middleware-level approach to support user-centric semantic service discovery. The presented middleware, called AIDAS, exploits context-awareness based on user/device/service profile metadata to provide personalized views on services of interest, and supports semantic-based matchmaking between requested and offered service capabilities. In addition, AIDAS addresses the crucial management issue of providing resource-constrained portable devices with needed semantic support features. Semantic support services, such as ontology repositories and inference engines, typically require a large amount of computational and memory resources that might not fit the properties of all mobile devices. AIDAS addresses this issue by transparently and dynamically adapting semantic-based discovery support to the properties of different access devices.

Anytime, anywhere social computing requires several support mechanisms and tools, including location and proximity systems, expressive representation models of physical place and user characteristics, and effective social-matching algorithms. Anytime, anywhere social-network computing also requires shared and interoperable vocabularies for modeling location and entity characteristics. Current solutions tend to address only a subset of these issues. We believe that the success of anytime, anywhere social computing depends on middleware solutions that separate social-network management concerns from application requirements. Our middleware solution, the socially aware and mobile architecture (SAMOA), integrates a set of common management facilities for personalizing location-dependent social networks, and for propagating social networks' visibility up to the application level.

Context-awareness is considered a key driving principle for the design and provisioning of adaptable pervasive services. Rightfully describing and interpreting context, however, is a challenging issue. Semantic technologies are emerging as effective means to describe and reason about context information and to allow unknown entities to have a common understanding of context. However, the exploitation of semantic technologies for the design/deployment of context-aware applications in pervasive environments replete with heterogeneous devices requires to address several issues. In particular, a crucial aspect is how to support semantic based service provisioning to mobile devices with limited capabilities. Novel solutions are required to transparently and dynamically adapt semantic-based service provisioning to the properties of different access devices. The paper proposes a middleware-level solution approach that exploits the visibility of two kinds of metadata (profiles and policies) to support the configurability of the semantic support functionalities depending on user/device properties, and that offers a wide set of mechanisms for making viable semantic based service provisioning even to resource-constrained portable devices.

The growing diffusion of portable devices enables users to benefit from anytime and anywhere impromptu collaboration. Appropriate policy models that take into account the dynamicity and heterogeneity of the new pervasive collaboration scenario are crucial to ensure secure sharing of information. Collaborating entities cannot be predetermined and resource availability frequently varies, even unpredictably, due to user/device mobility, thus complicating resource access control. Policies cannot be defined based on entity's identities/roles, as in traditional security solutions, or be specified a priori to face any operative run-time condition, and require continuous adjustments to adapt to the current situation. To address these issues this paper advocates the adoption of a semantic context-aware paradigm to policy specification. Context- awareness allows operations on resources to be controlled based on context visibility whereas semantic technologies allow the high-level description and reasoning about context/policies. The paper describes Proteus that, as a key feature, combines these two design guidelines to enable dynamic adaptation of policies depending on context changes. In particular, the paper shows how ontologies and logic programming rules can be used to leverage policy adaptation.

A mass market of users with differentiated preferences and heterogeneous wireless terminals will increasingly access services dynamically introduced by competitor providers. In next-generation mobile systems, novel solutions for user-centric service discovery are crucial to provide personalized views of only the services of potential interest. The service view personalization should be based on user context, for example, user preferences, access device capabilities, and environment conditions, and should exploit semantic technologies to allow flexible matching between requirements and capabilities in open and dynamic deployment scenarios. Our MIDAS middleware exemplifies how to exploit context awareness based on user/device/service profile metadata and semantic-based matchmaking.

Context-awareness is starting to emerge as a key driving principle for the design and provisioning of pervasive services in pervasive computing environments. Semantic languages seem to provide effective means to express, process and reason about context information and to facilitate knowledge sharing and interoperability among previously unknown entities. However, the exploitation of semantic languages for the design and deployment of context-aware applications requires to address several issues. In particular, semantic languages require complex and heavyweight support facilities, e.g., reasoning engines, ontology repositories and knowledge management tools, that may not fit the capabilities of portable devices, especially of resource-limited ones. Novel middleware-level solutions are required to transparently and dynamically adapt semantic-based service provisioning to the properties of different access devices. The paper proposes a novel middleware that exploits the visibility of two kinds of metadata, user/device/service profiles and policies, to tailor the configuration of the semantic support functionalities needed to access semantic-based services, and that offers a wide set of mechanisms for making viable semantic-based service provisioning to resource-constrained portable devices