Preface

This volume contains the proceedings of the Eleventh Workshop on Quantitative Aspects of Programming Languages and Systems (QAPL 2013), held in Rome, Italy, on 23 and 24 March, 2013. QAPL 2013 was a satellite event of the European Joint Conferences on Theory and Practice of Software (ETAPS 2013).

The central theme of the workshop is that of 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 behaviour 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. In particular, the workshop focuses on:

• the design of probabilistic, real-time and quantum languages, and the definition of semantical models for such languages;
• the discussion of methodologies for the analysis of probabilistic and timing properties (e.g. se- curity, safety, scheduability) and of other quantifiable properties such as reliability (for hardware components), trustworthiness (in information security) and resource usage (e.g. worst-case mem- ory/stack/cache requirements);
• the probabilistic analysis of systems which do not explicitly incorporate quantitative aspects (e.g. performance, reliability and risk analysis);
• applications to safety-critical systems, communication protocols, control systems, asynchronous hardware, and to any other domain involving quantitative issues.

The history of QAPL starts in 2001, when its first edition was held in Florence, Italy, as a satellite event of the ACM Principles, Logics, and Implementations of high-level programming languages, PLI 2001. The second edition, QAPL 2004, was held in Barcelona, Spain, as a satellite event of ETAPS 2004. Since then, QAPL has become a yearly appointment with ETAPS. In the following years, QAPL was held in Edinburgh, Scotland (QAPL 2005), Vienna, Austria (QAPL 2006), Braga, Portugal (QAPL 2007), Budapest, Hungary (QAPL 2008), York, UK (QAPL 2009), Paphos, Cyprus (QAPL 2010), Saarbru _cken, Germany (QAPL 2011) and Tallinn, Estonia (QAPL 2012).
The proceedings of the workshops upto and including 2009 are published as volumes in Electronic Notes in Theoretical Computer Science (ENTCS). The editions of 2010, 2011 and 2012 are published as volume 28, volume 57, and volume 85, respectively, of the Electronic Proceedings in Theoretical Computer Science (EPTCS).
Three special issues of the journal of Theoretical Computer Science are dedicated to the QAPL 2004, QAPL 2006 and QAPL 2010 events, and are published in Volume 346(1), Volume 382(1) and Volume 413(1) respectively. A special issue of the journal of Theoretical Computer Science dedicated to QAPL 2011 and QAPL 2012 is in preparation.

The workshop programme included two QAPL keynote presentations: Alessandra Di Pierro (University of Verona, Italy): Probabilistic static analysis and security trade-offs, and Paolo Zuliani (University of Newcastle, UK): Statistical Model Checking for Cyber-Physical Systems as well as two keynotes shared with MLQA: Martin Franzle (University of Oldenburg, Germany): A tight integration of symbolic, numeric, and statistical methods for the analysis of cyber-physical systems, and Flemming Nielson (Technical University of Denmark): Guarding against Denial of Service Attacks.

Furthermore, the Program Committee of QAPL 2013 which comprised of:

• Alessandro Aldini, University of Urbino, Italy
• Christel Baier, Technical University of Dresden, Germany
• Ezio Bartocci, Technical University of Vienna, Austria
• Marco Bernardo, University of Urbino, Italy
• Nathalie Bertrand, INRIA Rennes Bretagne Atlantique, France
• Luca Bortolussi (Co-chair), University of Trieste, Italy
• Tomas Brazdil, Masaryk University, Czech Republic
• Kostas Chatzikokolakis, CNRS, France
• Pedro D'Argenio, University of Cordoba, Argentina
• Alessandra Di Pierro, University of Verona, Italy
• Vashti Galpin, University of Edinburgh, UK
• Joost-Pieter Katoen, RWTH Aachen, Germany
• Richard Hayden, Imperial College, London
• Holger Hermanns, Saarland University, Germany
• Mieke Massink, Italian National Research Council - ISTI, Pisa, Italy
• Annabelle McIver, Macquarie University, Australia
• Gethin Norman, University of Glasgow, UK
• David Parker, Oxford University, UK
• Anne Remke, University of Twente, the Netherlands
• Jeremy Sproston, University of Turin, Italy
• Mirco Tribastone, LMU Munich, Germany
• Franck van Breugel, York University, Canada
• Herbert Wiklicky (Co-chair), Imperial College London, UK
• Verena Wolf, Saarland University, Germany

We would like to thank the QAPL steering committee for its support, the ETAPS 2013 organisers and furthermore all the authors, the invited speakers, the programme committee and the external referees for their valuable contributions.

May 2013

Luca Bortolussi and Herbert Wiklicky
Program Co-chairs