Stephan Reiff-Marganiec

Feature interaction: a critical review and considered forecast

The state of the art of the field of feature interactions in telecommunications services is reviewed, concentrating on three major research trends: software engineering approaches, formal methods, and on line techniques. Then, the impact of the new, emerging architectures on the feature interaction problem is considered. A forecast is made about how research in feature interactions needs to readjust to address the new challenges posed by the emerging architectures.

Markov-HTN Planning Approach to Enhance Flexibility of Automatic Web Service Composition

Automatic Web services composition can be achieved by using AI planning techniques. HTN planning has been adopted to handle the OWL-S Web service composition problem. However, existing composition methods based on HTN planning have not considered the choice of decompositions available to a problem which can lead to a variety of valid solutions.In this paper, we propose a model of combining a Markov decision process model and HTN planning to address Web services composition. In the model, HTN planning is enhanced to decompose a task in multiple ways and hence be able to find more than one plan,taking both functional and non-functional properties into account. Furthermore, an evaluation method to choose the optimal plan and some experimental results illustrate that the proposed approach works effectively.

A Method for Automated Web Service Selection

Automated Web service selection is a key challenge in Service Oriented Architecture (SOA) research. With SOA becoming more popular in industry, and more Web services becoming available in the e-business market, the main issue changes from service discovery to service selection and ranking. In this paper, we propose a novel nonfunctional property-based service selection method by modifying the Logic Scoring Preference (LSP) method with Ordered Weighted Averaging (OWA) Operators. Moreover, the dynamic mechanism for evaluating metadata based QoS criteria of each service is presented for this method.

Service Selection Based on Non-functional Properties

Service-oriented Architecture supports software to be composed from services dynamically. Selecting and composing appropriate services according to business process, policies and non-functional constraints is an essential challenge. This paper proposes a method for automatic selection of the most relevant service for composition based on non-functional properties and the users context. In doing this we also propose a method of obtaining and evaluating non-functional aspects.

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.

Towards Heuristic Web Services Composition Using Immune Algorithm

One of the main benefits of web services is the dynamic composability, however how to achieve this is one of the current research challenges. Web service composition has been studied and, amongst other methods, the use of natural computing methods has been proposed previously. In this paper, we address the need for a fast response when computing the most suitable sequence of services. In particular, we propose a novel heuristic immune algorithm with an efficient encoding and mutation method. The algorithm involves two steps: an immune selection operation, which is maintaining antibody population diversity and a clonal selection. The use of a vaccine during the evolution provides heuristic information that accelerates the convergence. Our experimental results illustrate that the proposed heuristic immune algorithm is very effective in improving the convergence speed.

A Backwards Composition Context Based Service Selection Approach for Service Composition

In SOA applications are built from individual services offered by different providers. Typically an application comprises of several such services usually stemming from different providers leading to the question of which services to select and compose. We present the new concept of composition context together with a novel service selection algorithm. The approach has been evaluated in our test bed and shows good scalability.

inContext: A Pervasive and Collaborative Working Environment for Emerging Team Forms

Participants in current team collaborations belong to different organizations, work on multiple objectives at the same time, and frequently change locations. They use different devices and infrastructures in collaboration processes that can last from a few hours to several years. All these factors pose new challenges to the development of collaborative working environments (CWEs). Existing CWEs are unable to support emerging teams because diverse collaboration services are not well integrated or adapting to the team context. We present the inContext approach to providing a novel pervasive CWE infrastructure for emerging team forms. inContext aggregates disparate collaboration services using Web services and Semantic Web technologies and provides a platform that captures diverse dynamic aspects of team collaborations. By utilizing runtime and historical context and interaction information, adaptation techniques can be deployed to cope with the changes of emerging teams.

StPowla: SOA, Policies and Workflows

We introduce StPowla , a workflow based approach to business process modelling that integrates a simple graphical notation, to ease the presentation of the core business process, a user---friendly policy language, Appel , to provide the necessary adaptation to the varied expectations of the various business stakeholders, and the Service Oriented Architecture, to assemble and orchestrate available services in the business process. We illustrate the approach with a loan approval process.