Middleware for Pervasive and Ad Hoc Computing

Ian Wakeman , University of Sussex Dan Chalmers , University of Sussex Michael Fry , University of Sydney Abstract: In this paper, we outline an approach to the identification of entities for access control that is based on the membership of groups, rather than individuals. By using group membership as a level of indirection between the individual and the system, we can increase privacy and provide incentives for better behaviour. Privacy comes from the use of pseudonyms generated within the group and which can be authenticated as belonging to the group. The incentives for better behaviour come from the continuous nature of groups - members may come and go, but the group lives on, and groups are organised so as to ensure group-longevity, and prevent actions which may harm the group’s reputation. We present a novel pseudonym generation mechanism suitable for use in groups without a centralised administration. Finally, we argue that the use of group membership as the basis for formulatin...

Salman Taherian , University of Cambridge Jean Bacon , University of Cambridge Abstract: With the increased realisation of the benefits of studying environmental data, sensor networks are rapidly scaling in size, heterogeneity of data, and applications. In this paper, we present a State-based Publish/Subscribe (SPS) framework for sensor systems with many distributed and independent application clients. SPS provides a state-based information deduction model that is suited to many classes of sensor network applications. State Maintenance Components (SMCs) are introduced that are simple in operation, flexible in placement, and decomposable for distributed processing. Publish/Subscribe communication forms the core messaging component of the framework. SPS uses the decoupling feature of Pub/Sub and extends this across the SMCs to support a more flexible and dynamic system structure. Our evaluation, using real sensor data, shows that SPS is expressive in capturing conditions, and scalable in...

Clemens Holzmann, Johannes Kepler University Linz Abstract: This paper is about a novel rule-based approach for reasoning about qualitative spatiotemporal relations among technology- rich autonomous objects, to which we refer to as artifacts. The objective of our work is to provide means for defining spatiotemporal constraints – i.e. logical combinations of spatial relations to artifacts at certain time intervals – at a high level of abstraction, and to recognize relative situations therewith. Such constraints are defined with rules that infer high-level relationships for newly recognized situations, which in turn can be used in other constraints. At any time, the history of known relationships can be queried in order to trigger predefined actions. We decided for qualitative abstractions of both spatial and temporal relationships, as they reflect the semantics of natural language terms and thus facilitate dealing with relationships at the application programming level. The core concept...

Luiz Olavo Bonino da Silva Santos, University of Twente Remco Poortinga – van Wijnen, Telematica Instituut Peter Vink, Philips Research Abstract: Context awareness has emerged as an important element in distributed computing. It offers mechanisms that allow applications to be aware of their environment and enable these applications to adjust their behavior to the current context. Considering the dynamic nature of context, the data flow of relevant contextual information can be significant. In order to keep track of this information flow, a flexible service mechanism should be available for the client applications. In this document we present a service-oriented middleware for context-aware applications. This middleware provides support to leverage the development of context-aware applications by providing a scripting-like approach for context-aware application development; allowing the subscription of rules containing context-based events and conditions and a notification to be sent whe...

Jos´e Viterbo F., Markus Endler, Department of Informatics, PUC-Rio Vagner Sacramento, Institute of Informatics UFG Abstract In ubiquitous computing systems, the mobility of users and their devices results in recurring disconnections and reconnections with different networks, and the corresponding dynamic change of the network and domain-specific resources and services accessible from the user’s device. On the other hand, some services are available to be used only by users that are located in a well defined region. In this highly dynamic and heterogeneous scenario, applications must be capable of discovering the appropriate instances of the required services in each visited network or region. In order to support such spontaneous interaction, we propose a discovery service based on the notion of a (geographic) location scope. This discovery service is one of the core services of the MoCA architecture, a middleware that supports the development and deployment of location-aware ubiquitou...

Sudong Chen, Eindhoven University of Technology Johan Lukkien , Eindhoven University of Technology Abstract: The Service Oriented Architecture (SOA) is used extensively in ubiquitous computing environments. Using external service orchestration, services can be composed into applications. Since cooperation takes place between services that are scattered over the Internet and belong to different parties, there is a growing need to protect the ownership of service providers and keep the security of communication messages in service composition. This paper shows the details of a service-oriented virtual community overlay network designed for secure external service orchestration. It can also provide contracted QoS guarantees that will definitely affect the overall performance of ubiquitous applications. Further, it highlights the working principle of access control policies as well as a service behavior monitoring mechanism using an example scenario. ACM Copyright Notice Copyright © by the...