Proceedings Ninth Workshop on Quantitative Aspects of Programming Languages

Abstract: This volume contains the proceedings of the Ninth Workshop on Quantitative Aspects of Programming Languages (QAPL 2011), held in Saarbrucken, Germany, April 1--3, 2011. QAPL 2011 is a satellite event of the European Joint Conferences on Theory and Practice of Software (ETAPS 2011). The workshop theme is on quantitative aspects of computation. These aspects are related to the use of physical quantities (storage space, time, bandwidth, etc.) as well as mathematical quantities (e.g. probability and measures for reliability, security and trust), and play an important (sometimes essential) role in characterising the behavior and determining the properties of systems. Such quantities are central to the definition of both the model of systems (architecture, language design, semantics) and the methodologies and tools for the analysis and verification of the systems properties. The aim of this workshop is to discuss the explicit use of quantitative information such as time and probabilities either directly in the model or as a tool for the analysis of systems.