QASBA 2013 – Proceedings

Foreword
The service-oriented computing paradigm has been widely adopted in enterprises as a means to implement distributed computing solutions. These solutions are realized as service-based applications (SBAs), by integrating heterogeneous software services, usually developed, controlled and owned by different organizations. Given the availability of mechanisms for run-time service discovery and binding, the service-oriented paradigm fosters a further level of dynamicity where service integration emerges at run time and evolves over time. Nevertheless the run-time integration of services owned and controlled by different organizations, as well as the unprecedented degree of change allowed in such systems, affects the notion of correctness, dependability, and quality of SBAs. This poses a challenge for the definition of new methodologies and techniques for the quality assurance process of this class of software. The consensus is that the quality assurance process has to span over the entire life cycle of a service-based application, integrating both design-time and run-time techniques; yet the approaches remain fragmented.

Quality Assurance at Design Time

Towards a Quality Modelling Language for Component-Based Systems (QML/CS)
Abdulrahman Alreshidi, Steffen Zschaler, and Peter McBurney
(King's College London, UK)
In the model-based development context, meta-model-based languages are dened and implemented, either in the general domain or for specic domains. Creating a new meta-model requires integration and the ability to maintain consistency throughout the various aspects of the models. QML/CS does not have a well-dened specication in terms of modelling non-functional properties of component-based software; in fact it provides an overview of what QML/CS could look like [12]. There is a recognised need for a re- ned quality modelling language for component-based systems (QML/CS); one way of achieving this is by dening a meta-model and its semantics. This research aims to dene and build a meta-model of QML/CS, which can be used to produce a well-dened specication that species the nonfunctional properties of component-based software. In this paper, the challenges QML/CS brings due to some special properties found in this type of language are discussed. In addition, the techniques that are available and can be applied to address the challenges are identied.

Verification of Variable Service Orchestrations using Model Checking
Selma Suloglu, Riza Aktunc, and Mustafa Yucefaydalı
(Middle East Technical University, Turkey; TÜBITAK Software Technologies Research Institute, Turkey)
Service orchestrations as architectural specifications specify collaborating services and the way they interoperate via information exchange. Some orchestration specifications, which describe the behavior of service-oriented systems, support variability in order to provide flexibility and to increase reusability of services. VxBPEL is one of these specifications, incorporating variability based on COVAMOF model by adaption of BPEL specification. In variable-intensive service systems such as VxBPEL orchestrations, verification is a costly and complex task due to having to check consistency of all possible orchestrations. To fulfill the need to formally verify variable orchestrations, a step by step transformation approach is proposed to apply model checking using Feature Transition Systems (FTS). This paper introduces transformation from VxBPEL to FTS model and produces required feature model of the variable orchestration and its fPromela specification.

Info

Quality Assurance at Run Time

Conformance Testing for Quality Assurance of Clustering Architectures
Afef Jmal Maâlej, Zeineb Ben Makhlouf, Moez Krichen, and Mohamed Jmaiel
(University of Sfax, Tunisia)
Given the scalability of load balancing based architectures, it is increasingly necessary to develop appropriate quality assurance methodologies and techniques, of which Testing is widely adopted and used one. This paper describes a distributed platform for checking the conformance between real functioning of a given load balancer and its specified requirements. Our solution is based on Timed Automata as model for testing supported load balancing algorithms. This paper also shows a novel prototype tool support, LBACT, implemented for quality assurance of load balancing based architectures. Finally, we illustrate our contribution in the context of BPEL clustering mechanisms.

Runtime Testing Framework for Improving Quality in Dynamic Service-Based Systems
Mariam Lahami, Moez Krichen, and Mohamed Jmaiel
(University of Sfax, Tunisia)
Service-based systems are operating in dynamic environments characterized by continual changes such as requirement evolution, service crash or service unavailability. In this context, improving the quality of these systems after such evolution is highly demanded. With the aim of checking their behaviors at runtime and detecting faults introduced after dynamic changes, a runtime testing approach is applied. An effective Runtime Testing Framework For Adaptable and Distributed Systems called RTF4ADS is then proposed. This framework is conceived in order to reduce runtime testing side effects as timing and resource usage costs, interference risks while improving its fault finding capabilities. To show the relevance of RTF4ADS prototype, a case study in the healthcare domain implemented in the OSGi platform is given.

Safe Substitution for Service-Based Applications
Shin Nakajima
(NII, Japan)
In order to have desired levels of flexibility, service-based applications (SBAs) are dynamically adapted to replace constituent software services at runtime. These services are owned, provided, and developed by third parties, which makes it difficult to know whether such service components introduce undesirable features into the SBA. It requires a new method to ensure that the replacement or substitution is safe. This paper proposes an integrity-based substitution checking method and uses an adaptive Web application as an example for demonstrating the effectiveness of the proposed approach.

QASBA 2013 – Proceedings

2013 2nd International Workshop on Quality Assurance for Service-Based Applications (QASBA)

Preface

Quality Assurance at Design Time

Quality Assurance at Run Time