Kenneth J. Turner

Feature interaction in policies

Feature interaction is a problem mostly considered in the context of telephony features, but present in other domains. In this paper we consider policies (independent of the system that they control) as an application domain for feature interaction techniques. We present the feature interaction problem as it occurs in the policy context and show how it can be approached. We give a taxonomy for policy conflict, and introduce a generic architecture for handling policy conflict.

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.

Formalising web services

Despite the popularity of web services, creating them manually is an intricate task. Composite web services are defined using the evolving standard for Bpel (Business Process Execution Logic). It is explained how Cress (Chisel Representation Employing Systematic Specification) has been extended to meet the challenge of graphically and formally describing web services. Sample Cress descriptions are presented of web services. These are automatically translated into Lotos, permitting rigorous analysis and automated validation.

Protocol-Inspired Hardware Testing

The relevance of protocol conformance testing techniques to hardware testing is discussed. It is shown that the ioconf (input-output conformance) approach used in protocol testing can be applied to generate tests for a synchronous hardware design using its formal specification. The generated tests are automatically applied to a circuit by a VHDL testbench, thus giving confidence that the hardware design meets its high-level formal specification. Case studies illustrate how the ideas can be applied to standard hardware verification benchmarks such as the Single Pulser and Black-Jack Dealer.

Services and Policies for Care At Home

It is argued that various factors including the increasingly ageing population will require more care services to be delivered to users in their own homes. Desirable characteristics of such services are outlined. The Open Services Gateway initiative has been adopted as a widely accepted framework that is particularly suitable for developing home care services. Service discovery in this context is enhanced through ontologies that achieve greater flexibility and precision in service description. A service ontology stack allows common concepts to be extended for new services. The architecture of a policy system for home care is explained. This is used for flexible creation and control of new services. The core policy language and its extension for home care are introduced, and illustrated through typical examples. Future extensions of the approach are discussed.

Relating architecture and specification

Abstract The problems of multiple specification languages for multiple architectures are discussed. It is concluded that an architectural semantics is of practical value in ensuring consistent and effective development of specifications. The approach is discussed in general and by examples, concentrating mainly on an architectural semantics for Open Systems Interconnection in relation to Estelle, Lotos and SDL. It is shown how an architectural semantics can be realised using a library of specification templates, allowing the specifier to work at a higher, more architectural level. Some Lotos templates are discussed, mainly for Open Systems Interconnection.

Towards personalised home care systems

Home care is increasingly seen as a promising alternative to traditional care services. Programming home care systems remains a significant challenge considering the potentially large scale of deployment, the differences between individual care needs, and the progressive nature of ageing. In this paper, we present ongoing work on programming home care systems to support personalisation, adaptability over time, and dependability. A policy-based approach is used to build such systems. We present the technical details of our approach, including a policy language for home care and the corresponding system architecture. Policy examples are used to illustrate how the approach supports personalisation of home care services.

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.

An Ontology-Based Actuator Discovery and Invocation Framework in Home Care Systems

Home care systems need to be personalised to meet individual needs, and must be easily adjusted as the users symptoms develop. Care policies (i.e. Event-Condition-Action rules) can be used to specify care services, facilitating changes in the behaviour of a home care system. Context modelling allows a user to specify the trigger and conditions of a care policy, using high-level context rather than raw sensor data. The actions of a care policy are, however, still dependent on the implementations details of actuators. We propose a framework that allows the actions of a care policy to be specified abstractly using human-understandable concepts. The framework takes care of discovering and using specific actuators, hiding the low-level home networking details from ordinary users. It therefore makes personalisation and modification of home care systems more accessible to ordinary users, requiring very little technical knowledge.

Use of Logic to Describe Enhanced Communications Services

New functionality is added to telecommunications systems in the form of features or services. However, this is a very provider-centric approach, not giving much control to the user. We consider a logic that allows the user to express preferences as to how they wish calls to be handled. This logic is encapsulated in a user-friendly policy description language. The transferability of a policy description language (Ponder) developed for system management and access control is discussed.