The STRESS Method for Boundary-point Performance Analysis of End-to-end Multicast Timer-Suppression Mechanisms

Evaluation of Internet protocols usually uses random scenarios or scenarios based on designers' intuition. Such approach may be useful for average-case analysis but does not cover boundary-point (worst or best-case) scenarios. To synthesize boundary-point scenarios a more systematic approach is needed.In this paper, we present a method for automatic synthesis of worst and best case scenarios for protocol boundary-point evaluation. Our method uses a fault-oriented test generation (FOTG) algorithm for searching the protocol and system state space to synthesize these scenarios. The algorithm is based on a global finite state machine (FSM) model. We extend the algorithm with timing semantics to handle end-to-end delays and address performance criteria. We introduce the notion of a virtual LAN to represent delays of the underlying multicast distribution tree. The algorithms used in our method utilize implicit backward search using branch and bound techniques and start from given target events. This aims to reduce the search complexity drastically. As a case study, we use our method to evaluate variants of the timer suppression mechanism, used in various multicast protocols, with respect to two performance criteria: overhead of response messages and response time. Simulation results for reliable multicast protocols show that our method provides a scalable way for synthesizing worst-case scenarios automatically. Results obtained using stress scenarios differ dramatically from those obtained through average-case analyses. We hope for our method to serve as a model for applying systematic scenario generation to other multicast protocols.Comment: 24 pages, 10 figures, IEEE/ACM Transactions on Networking (ToN) [To appear

On the Automated Synthesis of Enterprise Integration Patterns to Adapt Choreography-based Distributed Systems

The Future Internet is becoming a reality, providing a large-scale computing environments where a virtually infinite number of available services can be composed so to fit users' needs. Modern service-oriented applications will be more and more often built by reusing and assembling distributed services. A key enabler for this vision is then the ability to automatically compose and dynamically coordinate software services. Service choreographies are an emergent Service Engineering (SE) approach to compose together and coordinate services in a distributed way. When mismatching third-party services are to be composed, obtaining the distributed coordination and adaptation logic required to suitably realize a choreography is a non-trivial and error prone task. Automatic support is then needed. In this direction, this paper leverages previous work on the automatic synthesis of choreography-based systems, and describes our preliminary steps towards exploiting Enterprise Integration Patterns to deal with a form of choreography adaptation.Comment: In Proceedings FOCLASA 2015, arXiv:1512.0694

Testing Mobile Web Applications for W3C Best Practice Compliance

Adherence to best practices and standards when developing mobile web applications is important to achieving a quality outcome. As smartphones and tablet PCs continue to proliferate in the consumer electronics market, businesses and individuals are increasingly turning from the native application paradigm to HTML 5-based web applications as a means of software development and distribution. With an everincreasing reliance by users on the correct functioning of such applications, the requirement for stringent and comprehensive quality assurance measures is also brought sharply into focus. This research investigates the increasing trend towards mobile web application development in the mobile software domain, and assesses the requirement for an automated approach to best practice validation testing for mobile web applications. Contemporary approaches to automated web application testing are examined, with particular emphasis on issues relating to mobile web application tests. The individual guidelines proposed by the W3C Mobile Web Application Best Practices are analysed and where applicable automated conformance tests are implemented in a customised testing tool. A range of mobile web applications are tested using this tool in order to examine the extent to which implementation of the tested-for guidelines is detected. Automated tests were successfully implemented in respect of nearly 60% of the best practices