Mobile and ubiquitous computing emphasize the need for highly adaptive delivery of Internet services. While several systems and even products exist that guarantee shallow or deep adaptation, they are usually based on profile information and customer relationship management modules stored and operating at the service provider. On the contrary, We assume that profile information, including user personal data and preferences, device capabilities, network bandwidth, location and other contextual information, as well as policy rules that can dynamically change this data, are provided by different sources. We describe a formal framework for aggregating this information and for solving conflicts between policy rules. We provide both a theoretical study of the properties of our techniques and a practical evaluation study obtained through a prototype implementation.

We present a novel technique to combine services, provided by mobile as well as fixed devices, on-the-fly and in a context-sensitive way within smart environments containing groups of people. The key intuition at the base of our approach is that, in those environments, similar functions are provided simultaneously by many agents on board of different devices; the issue becomes then of combining and coordinating their services in order to exploit their aggregated power or improve delivery. At the core of our work is the idea of implicit organizations, that is, teams of agents that continuously renegotiate how to provide services while the environment evolves. A concept demonstrator shows how implicit organizations can support a smart virtual meeting room. We foresee the application of our approach in assisting users and groups of users in active environments, such as an active museum. Here, our approach can enhance knowledge transfer and communication for groups visiting together cultural exhibits.

In a CDMA2000 network, a mobile node (MN) gets packet data service by establishing a PPP session with a packet data serving node (PDSN). The PDSN acts as the muter for the IP packets transported over the PPP session. A packet control function (PCF) sits between the radio access network and the packet network, selects the PDSN for the MN during session setup, and relays the PPP frames between the MN and the PDSN during the session. The PCF selects a PDSN based on the MN's device identity. Due to this, the data services that a mobile user subscribes become tightly coupled with the device that the user registers with the service provider. Because the PCF selects a PDSN based only on mobile device identity, it is unable to select the "best" PDSN to support the services subscribed by a specific user. This work presents the design and implementation of an entity called radio-packet session redirector (RPSR) that works within the current standard and alleviates this shortcoming. The RPSR intercepts a PPP session, parses the user identity, selects a PDSN based on the user identity, creates a PPP session with the selected PDSN and splices the sessions together so that PPP frames can be seamlessly forwarded between the MN and the PDSN with very little overhead. We identify a number of services that RPSR enables in the network. We describe a prototype stand-alone device implementation of the RPSR in the Linux kernel and present performance results.

We consider the problem of interconnecting hosts in spontaneous edge networks composed of various types of wired or wireless physical and link layer technologies. We argue that this kind of networks requires a more sophisticated approach than standard IP forwarding: communication paths should be managed on a per flow basis, multiple paths need to be maintained to cope with link failures or changing topologies, and the interconnection architecture should provide a means for acquiring the information on destination reachability. To experiment with our approach, we have designed and implemented Lilith, a prototype of an interconnection node for spontaneous edge networks. We handle network dynamics by establishing MPLS (multi protocol label switching) label switched paths (LSP) on demand with a reactive ad hoc routing protocol. We present some measurements that show good performance with respect to the standard IP forwarding and important performance gains when multiple paths are used.

Sensor readings in a wireless microsensor network are correlated both spatially and temporally. Various coding and storage schemes and also other applications have been developed to exploit these correlations; therefore it is crucial to efficiently track the correlations. In this paper, a linear prediction algorithm is developed to initially establish the correlations, and the order of linear prediction has been derived from the prediction error power distribution. A tracking algorithm uses discrete Kalman filter to track the correlation once it is initially obtained. This Kalman filter based algorithm uses the gradient computed at each step as the input control vector. This approach is suitable for quantifying geographical spatial correlation and multimodality correlation. Experimental results using various data sets have shown that the proposed scheme can accurately obtain the correlation and consumes much less energy as compared to known schemes.

This paper highlights intrusiveness as a key issue in the field of pervasive computing environments and presents a multiagent approach to tackling it. Specifically, we discuss how interruptions can impact on individual and group tasks and how they can be managed by taking into account user and group preferences through negotiation between software agents. The system we develop is implemented on the Jabber platform and is deployed in the context of a meeting room scenario.

This work presents an approach for the dynamic management of the content of several Universal Description, Discovery, and Integration (UDDI) registries. By content, it is meant the announcements of Web services that providers post on various distributed UDDI registries. Unlike other initiatives in the field of Web services, our concerns are the following: availability of several UDDI registries, no predefined communication infrastructure between the UDDI registries, and no centralized component to coordinate the UDDI registries. The solution presented in this paper integrates users and software agents into what we call messengers. When a user is in the vicinity of an UDDI registry, his software agent, which resides in his mobile device, interacts with that registry. The objective is to submit the details on Web services that are stored in the mobile device.

Tuple spaces offer a coordination infrastructure for communication between autonomous entities by providing a logically shared memory along with data persistence, transactional security as well as temporal and spatial decoupling - properties that make it desirable in distributed systems for e-commerce and pervasive computing applications. In most tuple space implementations, tuples are retrieved by employing type-value matching of ordered tuples, object-based polymorphic matching, or XML-style pattern matching. In a heterogeneous environment, this can pose several limitations. This paper discusses the architecture and implementation of a prototype semantic infrastructure, which uses semantic Web technologies to represent and retrieve tuples from a tuple space. Semantic tuple spaces (sTuples) overcomes limitations of the JavaSpaces tuple space implementation, by making use of a Web ontology language and RACER, a description-logic reasoning engine. The sTuples infrastructure extends and integrates with Vigil, a secure framework for communication and access of intelligent services in a pervasive environment. Specialized agents, such as the tuple-recommender agent, task-execution agent and publish-subscribe agent, which have a better understanding of the environment, reside on the tuple space and play an important role in providing user-centric reasoning.