Performance Testing of Distributed Component Architectures

Performance characteristics, such as response time, throughput andscalability, are key quality attributes of distributed applications. Current practice,however, rarely applies systematic techniques to evaluate performance characteristics.We argue that evaluation of performance is particularly crucial in early developmentstages, when important architectural choices are made. At first glance, thiscontradicts the use of testing techniques, which are usually applied towards the endof a project. In this chapter, we assume that many distributed systems are builtwith middleware technologies, such as the Java 2 Enterprise Edition (J2EE) or theCommon Object Request Broker Architecture (CORBA). These provide servicesand facilities whose implementations are available when architectures are defined.We also note that it is the middleware functionality, such as transaction and persistenceservices, remote communication primitives and threading policy primitives,that dominates distributed system performance. Drawing on these observations, thischapter presents a novel approach to performance testing of distributed applications.We propose to derive application-specific test cases from architecture designs so thatthe performance of a distributed application can be tested based on the middlewaresoftware at early stages of a development process. We report empirical results thatsupport the viability of the approach

Formální komponentový model pro mobilní architektury

Disertační práce se zabývá modelováním komponentových systémů a formálním popisem jejich chování. Řešení je založeno na vlastním komponentovém modelu, který je popsán meta-modelem, z logického pohledu, a popisem v pi-kalkulu, z procesního pohledu. Je ukázáno, že komponentový model pokrývá dynamické aspekty softwarových architektur včetně mobility jejich komponent. Dále je popsán způsob modelování chování v architekturách orientovaných na služby a přechod ke komponentovým systémům. Chování konkrétní architektury orientované na služby lze pak vyjádřit jako jediný proces v pi-kalkulu. V závěru práce je navržené řešení ověřeno na případové studii prostředí pro testování kritických aplikací. Přínosem disertační práce je zejména zmíněná podpora dynamických architektur a integrace s architekturami orientovanými na služby.In the thesis, we propose an approach to modelling of component-based systems and formal description of their behaviour. The approach is based on a novel component model defined by a metamodel in a logical view and by description in the pi-calculus in a process view. We show that the component model addresses the dynamic aspects of software architectures including the component mobility. Furthermore, we propose a method of behavioural modelling of service-oriented architectures to pass smoothly from service level to component level and to describe behaviour of a whole system, services and components, as a single pi-calculus process. Finally, we illustrate an application of our approach on a case study of an environment for functional testing of complex safety-critical systems. The support of dynamic architecture and the integration with service-oriented architecture compromise the main advantages of our approach.Katedra softwarového inženýrstvíDepartment of Software EngineeringFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult

Towards Identifying and closing Gaps in Assurance of autonomous Road vehicleS - a collection of Technical Notes Part 1

This report provides an introduction and overview of the Technical Topic Notes (TTNs) produced in the Towards Identifying and closing Gaps in Assurance of autonomous Road vehicleS (Tigars) project. These notes aim to support the development and evaluation of autonomous vehicles. Part 1 addresses: Assurance-overview and issues, Resilience and Safety Requirements, Open Systems Perspective and Formal Verification and Static Analysis of ML Systems. Part 2: Simulation and Dynamic Testing, Defence in Depth and Diversity, Security-Informed Safety Analysis, Standards and Guidelines