Lynne Blair

Reflection, self-awareness and self-healing in OpenORB

There is a growing interest in the area of self-healing systems. Self-healing does however impose considerable demands on system infrastructures---especially in terms of openness and support for reconfigurability. This paper proposes that the self-awareness inherent in reflective technologies lends itself well to the construction of self-healing systems. In particular, the paper examines the support provided by the Open ORB reflective middleware technology for the construction of this increasingly important class of system.

Policy support for call control

The need for policies to control calls is justified by the changing face of communications. It is argued that call control requires distinctive capabilities in a policy system. A specialised policy language called APPEL (ACCENT Project Policy Environment/Language) has therefore been developed for this purpose. However, the policy language is cleanly separated into a core plus specialisations for various application domains. The paper describes both the foundation and the call control ontologies. Sample policy examples are provided to illustrate use for call control. The paper also presents the policy system architecture in which the policy language is interpreted. The components of the policy system are described, particularly the policy server and the policy wizard.

Exploring sustainability research in computing: where we are and where we go next

This paper develops a holistic framework of questions which seem to motivate sustainability research in computing in order to enable new opportunities for critique. Analysis of systematically selected corpora of computing publications demonstrates that several of these question areas are well covered, while others are ripe for further exploration. It also provides insight into which of these questions tend to be addressed by different communities within sustainable computing. The framework itself reveals discursive similarities between other existing environmental discourses, enabling reflection and participation with the broader sustainability debate. It is argued that the current computing discourse on sustainability is reformist and premised in a Triple Bottom Line construction of sustainability. A radical, Quadruple Bottom Line alternative is explored as a new vista for computing research.

Policies and conflicts in call control

Policy-based management is introduced and related to the specific needs of call control. It is explained how policies differ in important ways from features. Related work on policy-based management is reviewed, leading to the conclusion that a different approach is required for call control. A general architecture is presented for a policy system. This includes an overview of the major policy components, relating them to the system under control and to the context system that provides additional information. As a framework for explaining how policy conflicts are handled, the policy language for call control is briefly presented along with some sample policies. The paper then focuses on how policy conflicts are defined and resolved, using sample resolutions to illustrate the approach. Pointers are given to future enhancements to policy support, including new applications of policies to novel domains.

A framework for policy driven auto-adaptive systems using dynamic framed aspects

This paper describes and evaluates a framework that allows adaptive behaviour to be applied to systems by using a combination of dynamic Aspect-Oriented Programming (AOP), parameterisation and policies. Our approach allows the operator to create policies to define adaptive behaviour based on Event-Condition-Action rules. The combination of dynamic AOP with parameterisation aids reuse and allows aspects to be generated to suit the current system conditions; these aspects can then be woven at run time to adapt the application behaviour. This approach is evaluated in two ways; firstly performance measurements are presented to show that such behaviour does not add a substantial overhead to the target system. Secondly, Aspect-Oriented software metrics are applied to the adaptations applied to illustrate their reusability and flexibility.

Rethinking plan A for sustainable HCI

This paper challenges the sustainable HCI community to move away from a focus on demand and instead address climate change as a supply problem. We identify a new route to impact, namely addressing the psychological barriers that interfere with political mobilization toward limiting the use of fossil fuels. Five barriers are explored as a means of re-focusing research objectives for the community.

Patterns of persuasion for sustainability

Research into the values motivating unsustainable behavior has generated unique insight into how NGOs and environmental campaigns contribute toward successfully fostering significant and long-term behavior change, yet thus far this research has not been applied to the domain of sustainable HCI. We explore the implications of this research as it relates to the potential limitations of current approaches to persuasive technology, and what it means for designing higher impact interventions. As a means of communicating these implications to be readily understandable and implementable, we develop a set of antipatterns to describe persuasive technology approaches that values research suggests are unlikely to yield significant sustainability wins, and a complementary set of patterns to describe new guidelines for what may become persuasive technology best practice.

An adaptive run time manager for the dynamic integration and interaction resolution of features

With modern software systems, an important requirement is the ability to be auto adaptive, i.e. being able to adjust itself its changing environment. In line with this, a run time manager for dynamic feature integration of telecommunication systems, interaction detection and resolution is described in this paper with aspects being used to implement features. The manager manages the interaction of features/aspects by monitoring the managed program. The program is represented by a labelled transition system (LTS) model, stored in a flexible data structure, and executed by calling the action subroutine represented by the label of the LTS model, forming a reflective facility for the composition and analysis of features. It is the reflective mechanism that makes dynamic feature addition, run time model checking, as well as adaptive interaction resolution possible. Runtime model checking is possible because the checked program is stored within itself and the interaction resolution is done by selecting behaviour traces according to the resolution rules.

The role of reflection in supporting dynamic QoS management functions

In previous papers, the authors have reported on the design and implementation of reflective middleware platforms. The aim of this paper is to consider the implications of such an architecture for the area of quality of service (QoS) management. More specifically, the paper describes how critical QoS management functions can be incorporated into our reflective middleware platform, with particular emphasis on the dynamic QoS management functions of QoS monitoring and adaptation. It is argued that the reflective approach leads to a natural and highly flexible implementation of such QoS management functions (and indeed the approach offers considerable benefits over more conventional approaches).

COMPOSITION IN MULTI-PARADIGM SPECIFICATION TECHNIQUES

This paper addresses the issue of composition in a multi-paradigm environment. Our work focuses on the application domain of distributed multimedia systems and, in addition to considering quality of service properties, we also explore dynamic quality of service management functions based on the concepts of monitors and controllers. We advocate the use of a multi-paradigm specification technique which, to suit our chosen application domain, consists of LOTOS, real-time temporal logic and timed automata specifications. We illustrate our approach by giving an example of a simple phone system, extended with dynamic QoS management capabilities.