It is with great pleasure that we present to you this tutorial volume entitled Validation of Stochastic Systems.ItisoneoftheresultsoftheDutch-German- lateral cooperation project "Validation of Stochastic Systems" (VOSS), ?nanced by NWO and DFG (the Dutch and German science foundations, respectively). In the early days of 2002, the idea emerged to organize a seminar at Schloss Dagstuhl, not the usual Dagstuhl seminar with primarily invited participants, but a seminar aimed at young(er) people, and for which the organizers assign themes to be worked upon and presented on. Following an open call announced via the Internet in the spring of 2002, we received many applications for part- ipation. After a selection procedure, we decided to assign (mostly) teams of two researchers to work on speci?c topics, roughly divided into the following four theme areas: "Modelling of Stochastic Systems," "Model Checking of Stochastic Systems," "Representing Large State Spaces," and "Deductive Veri?cation of Stochastic Systems." These are the titles of the four parts of this volume. TheseminarwasheldinSchlossDagstuhlduringDecember8-11,2002aspart of the so-called GI/Research Seminar series. This series of seminars is ?nancially supported by theGesellschaft fur ] Informatik, the German Computer Society. At that point in time the papers had already undergone a ?rst review round. Each of the tutorial papers was presented in a one-hour session, and on the basis of the presentations we decided to bring together a selection of them into a book."

In the design, implementation, and operational planning of computer and c- municationsystems, manyquestionsregardingthe desiredcapacityandspeed of (sub)systems have to be answered.At this point, performance anddependability evaluation techniques can be of great help. With these techniques, design de- sions can be prepared using advanced methods to construct appropriatemodels, toparameterisethesemodels, andtosolvethem.Theapplicationofabroadsp- trum of such methods and techniques is currently supported by tools (mostly software, but sometimes partly hardware as well). Such tools enable system - signers and engineers to construct their models in a ?exible and modular way using high-level application-oriented modelling languages, to solve their models with a variety of techniques and to exercise parametric studies at ease. The goal of the 11th International Conference on Modelling Tools and Techniques for Computer and Communication System Perf- mance Evaluation (\TOOLS 2000") was to further develop the theory and technologyfortool-basedperformanceanddependability evaluationofcomputer and communication systems. Important themes included software tools, eval- tion techniques, measurement-based tools and techniques, performance and - pendabilityevaluationtechniquesbasedonformalmethods, casestudiesshowing the role of evaluation in the design of systems, and application studies in the area of centralised and distributed computer systems. Previous conferences in this series were held over the past 15 years in Paris (1984), Sophia Antipolis (1985), Paris(1987), Palma de Mallorca (1988), Torino (1991), Edinburgh (1992), Wien (1994), Heidelberg (1995), Saint Malo (1997), and Palma de Mallorca (1998). The proceedings of the latter four conferences also appeared in the series Lecture Notes in Computer Science (Volumes 794, 977, 1245, and 1469, respectively).

This book constitutes the proceedings of the 12th International Conference on Quantitative Evaluation of Systems, QEST 2015, held in Madrid, Spain, in September 2015. The 19 papers presented were carefully reviewed and selected from 42 submissions. They are organized in topical sections named: modelling and applications; tools; petri nets, process algebra and fault trees; applications; and queuing systems and hybrid systems. The book also contains one full-paper invited talk.

This book constitutes the proceedings of the 18th International GI/ITG Conference on Measurement, Modelling and Evaluation of Computing Systems and Dependability and Fault Tolerance, MMB & DFT 2016, held in Munster, Germany, in April 2016. The 12 full papers and 3 short papers included in this volume were carefully reviewed and selected from 23 submissions. The papers deal with the fields of performance evaluation, dependability, and fault-tolerance of computer and communication systems. A relatively new topic of smart grids is also covered.