Abstract. The emergence of handheld devices associated with wireless technologies has introduced new challenges for middleware. First, mobility is becoming a key characteristic; mobile devices may move around different areas and have to interact with different types of networks and services, and may be exposed to new communication paradigms. Second, the increasing number and diversity of devices, as in particular witnessed in the home environment, lead to the advertisement of supported services according to different service discovery protocols as they come from various manufacturers. Thus, if networked services are advertised with protocols different than those supported by client devices, the latter are unable to discover their environment and are consequently isolated. This paper presents a system based on event-based parsing techniques to provide full service discovery interoperability to any existing middleware. Our system is transparent to applications, which are not aware of the existence of our interoperable system that adapts itself to both its environment across time and its host to offer interoperability anytime anywhere. A prototype implementation of our system is further presented, enabling us to demonstrate that our approach is both lightweight in terms of resource usage and efficient in terms of response time. 1

Today’s wireless networks and devices support the dynamic composition of mobile distributed systems, according to device connectivity. This has in particular led to the introduction of a number of supporting middleware. However, such solutions need to be complemented with adequate modeling and verification support towards enforcing the correctness of the dynamic mobile systems with respect to both functional and non-functional properties. Building on the elegant properties of software architecture modeling, this paper introduces base modeling of mobile software components, which integrates key features of the wireless infrastructure and allows for reasoning about the behavior of dynamically composed systems. 1.

Web services are todays preferred vehicle for creating service-oriented architectures (SOA). Due to the boom of personal networked devices, the Web also found its way to the mobile space. This gives rise to device hosted mobile services that deliver functionality over a wireless network. There is potential to unite these services in a collaborative service space and exploit them as building blocks for distributed applications. This paper concentrates on a light-weight middleware layer to facilitate the integration, accessibility and orchestration of Webbased services in heterogeneous environments. Leveraging Web technology, this layer allows to interconnect serverless, peer-to-peer services deployed across federations of devices. We present its value in a ubiquitous application. 1

Abstract. Incentive scheme for stimulating service provision in Mobile Ad hoc NETworks (MANET) has been under intensive investigation due to its significance to the operation of MANET. This paper applies distributed algorithmic mechanism design and utilizes Vickrey auction for service allocation in mobile ad hoc networks. We show that our method stimulates service provision and achieves desired system-wide service allocation in spite of each agent’s selfish behavior, while introducing challenges from the inherent shortcomings of Vickrey auction and characteristics of MANET. We discuss the challenges, the existing solutions for wireline networks and propose a system model for service allocation in MANET. 1

Mobile ad hoc networks (MANET) pave the way for pervasive computing due to inherent support for anytime, anywhere network access for mobile users. Nonetheless, the highly dynamic nature of mobile ad hoc networks poses tremendous challenges for the development of applications since the application’s context keeps changing over time. One approach to master this complexity lies in the management of groups over MANET, i.e., applications execute on top of groups that manage the dynamic execution context, including mobility-related failures. There has been extensive research on group maninria-00415906,

In this paper we present CoWSAMI, a middleware infrastructure that enables context awareness in open ambient intelligence environments, consisting of mobile users and context sources that become dynamically available as the users move from one location to another. A central requirement in such dynamic scenarios is to be able to integrate new context sources and users at run time. CoWSAMI exploits a novel approach towards this goal. The proposed approach is based on utilizing Web services as interfaces to context sources and dynamically updateable relational views for storing, aggregating and interpreting context. Context rules are employed to provide mappings that specify how to populate context relations, with respect to the different context sources that become dynamically available. An underlying context sources discovery mechanism is utilized to maintain context information up-to-date as context sources and users get dynamically involved. Key words: ambient intelligence environments, context-awareness, middleware, Web services PACS: ∗ Corresponding author.

Abstract. The computing and networking capacities of today’s wireless portable devices allow for pervasive services, which are seamlessly networked. Indeed, wireless handheld devices now embed the necessary resources to act as both service clients and providers. However, the seamless networking of services remains challenged by the inherent mobility and resource constraints of devices, which make services a priori highly volatile. This paper discusses the design, implementation and experimentation of the ubiSOAP service-oriented middleware, which leverages wireless networking capacities to effectively enable the seamless networking of services. ubiSOAP specifically defines a layered communication middleware that underlies standard SOAP-based middleware, hence supporting legacy services while exploiting nowadays pervasive connectivity. 1

Abstract. Wireless devices now hold multiple radio interfaces, allowing to switch from one network to another according to required connectivity and related quality. Still, the selection of the best radio interface for a specific connection is under the responsibility of the end-user in most cases. Integrated multi-radio network management so as to improve the overall performance of the network(s) has led to a number of research efforts over the last few years. However, several challenges remain due to the inherent complexity of the problem. This paper specifically concentrates on the comprehensive analysis of energy-efficient multi-radio networking for pervasive computing. Building upon the service oriented architectural style, we consider pervasive networks of services, which are deployed on the various networked nodes. The issue is then to optimize the energetic performance of the pervasive network through careful selection of the radio link over which service access should be realized for each such access. This leads us to examine first the energetic performance of service access for most common wireless interfaces in use today (Bluetooth, WiFi and GPRS) and then introduce a formal model of service-oriented multi-radio networks. The proposed model enables characterizing the optimal network configuration in terms of energetic performance, which is shown to be a NP-hard problem and thus requires adequate approximation. 1

Pervasive computing environments aim at providing users with advanced services, dynamically composed our of networked services. In these open environments, availability of specific networked service instances cannot be guaranteed over time as users move and services leave and join the network accordingly. A major challenge in pervasive environments is thus to maintain services functionalities despite the dynamics of the environment, which induces connectivity loss with service instances. In this paper, we analyse the requirements to make distributed composite services able to face connectivity loss, i.e., able to dynamically adapt their configuration according to the networking environment. We then discuss the adaptation of relevant techniques that originate in the fault tolerance domain to the specifics of pervasive computing. 1

Pervasive computing appears like a new computing era based on networks of objects and devices evolving in a real world, radically different from distributed computing, based on networks of computers and data storages. Contrary to most context-aware approaches, we work on the assumption that pervasive software must be able to deal with a dynamic software environment before processing contextual data. After demonstrating that SOA (Service oriented Architecture) and its numerous principles are well adapted for pervasive computing, we present our extended SOA model for pervasive computing, called Service Lightweight Component Architecture (SLCA). SLCA presents various additional principles to meet completely pervasive software constraints: software infrastructure based on services for devices, local orchestrations based on lightweight component architecture and finally encapsulation of those orchestrations into composite services to address distributed composition of services. We present a sample application of the overall approach as well as some relevant measures about SLCA performances. 1