Paddy Nixon

A survey of autonomic communications

Autonomic communications seek to improve the ability of network and services to cope with unpredicted change, including changes in topology, load, task, the physical and logical characteristics of the networks that can be accessed, and so forth. Broad-ranging autonomic solutions require designers to account for a range of end-to-end issues affecting programming models, network and contextual modeling and reasoning, decentralised algorithms, trust acquisition and maintenance---issues whose solutions may draw on approaches and results from a surprisingly broad range of disciplines. We survey the current state of autonomic communications research and identify significant emerging trends and techniques.

Using trust for secure collaboration in uncertain environments

The SECURE project investigates the design of security mechanisms for pervasive computing based on trust. It addresses how entities in unfamiliar pervasive computing environments can overcome initial suspicion to provide secure collaboration.

Ontology-based models in pervasive computing systems

Pervasive computing is by its nature open and extensible, and must integrate the information from a diverse range of sources. This leads to a problem of information exchange, so sub-systems must agree on shared representations. Ontologies potentially provide a well-founded mechanism for the representation and exchange of such structured information. A number of ontologies have been developed specifically for use in pervasive computing, none of which appears to cover adequately the space of concerns applicable to application designers. We compare and contrast the most popular ontologies, evaluating them against the system challenges generally recognized within the pervasive computing community. We identify a number of deficiencies that must be addressed in order to apply the ontological techniques successfully to next-generation pervasive systems.

Delivering real-world ubiquitous location systems

To be widely adopted, location-aware computing must be as effortless, familiar, and rewarding as searching the Web. There are many challenges to this quest, but recent progress has demonstrated accurate location estimation using available wireless networking.

Group recommender systems: a critiquing based approach

Group recommender systems introduce a whole set of new challenges for recommender systems research. The notion of generating a set of recommendations that will satisfy a group of users, with potentially competing interests, is challenging in itself. In addition to this we must consider how to record and combine the preferences of many different users as they engage in simultaneous recommendation dialogs. In this paper we introduce a group recommender system that is designed to provide assistance to a group of friends trying to plan a skiing vacation.

Trusting collaboration in global computing systems

A significant characteristic of global computing is the need for secure interactions between highly mobile entities and the services in their environment. Moreover, these decentralised systems are also characterised by partial views over the state of the global environment, implying that we cannot guarantee verification of the properties of the mobile entity entering an unfamiliar domain. Secure in this context encompasses both the need for cryptographic security and the need for trust, on the part of both parties, that the interaction will function as expected. In this paper, we explore an architecture for interaction/ collaboration in global computing systems. This architecture reflects the aspects of the trust lifecycle in three stages: trust formation, trust evolution and trust exploitation, forming a basis for risk assessment and interaction decisions.

Towards self-protecting ubiquitous systems: monitoring trust-based interactions

The requirement for spontaneous interaction in ubiquitous computing creates security issues over and above those present in other areas of computing, deeming traditional approaches ineffective. As a result, to support secure collaborations entities must implement self-protective measures. Trust management is a solution well suited to this task as reasoning about future interactions is based on the outcome of past ones. This requires monitoring of interactions as they take place. Such monitoring also allows us to take corrective action when interactions are proceeding unsatisfactorily. In this vein, we first present a trust-based model of interaction based on event structures. We then describe our ongoing work in the development of a monitor architecture which enables self-protective actions to be carried out at critical points during principal interaction. Finally, we discuss some potential directions for future work.

Ontonym: a collection of upper ontologies for developing pervasive systems

Pervasive systems present the need to interpret large quantities of data from many sources. Context models support developers working with such data by providing a shared representation of the environment on which to base this interpretation. This paper presents a set of requirements for a context model that addresses uncertainty, provenance, sensing and temporal properties of context. Based on these requirements, we describe Ontonym, a set of ontologies that represent core concepts in pervasive computing. We propose a framework for evaluating ontologies in the pervasive computing domain by combining recognised techniques from the literature, and present a preliminary evaluation of Ontonym using these criteria.

Cross-Layer Architectures for Autonomic Communications

Layered architectures are not flexible enough to cope with the dynamics of wireless dominated next generation communications. Cross-layer architectures may provide a more flexible solution: breaks the traditional structure by allowing interactions between two or more non-adjacent layers. This paper review the cross–layer approach to network architecture and compare the different cross-layering architectures, observing that most current approaches depend purely on local information and provide only poor and inaccurate information gathering at the global scale. This paper also explores the possible use of cross-layering architectures in autonomic communications and the potential importance of new cross-layer architectures with a hybrid local and global view for autonomic communications.

More principled design of pervasive computing systems

Pervasive computing systems are interactive systems in the large, whose behaviour must adapt to the users changing tasks and environment using different interface modalities and devices. Since the system adapts to its changing environment, it is vital that there are close links between the structure of the environment and the corresponding structured behavioural changes. We conjecture that predictability in pervasive computing arises from having a close, structured and easily-grasped relationship between the context and the behavioural change that context engenders. In current systems this relationship is not explicitly articulated but instead exists implicitly in the systems reaction to events. Our aim is to capture the relationship in a way that can be used to both analyse pervasive computing systems and aid their design. Moreover, some applications will have a wide range of behaviours; others will vary less, or more subtly. The point is not so much what a system does as how what it does varies with context. In this paper we address the principles and semantics that underpin truly pervasive systems.