All deadlines are Anywhere on Earth.

The International Conference on Quantitative Evaluation of SysTems (QEST) is the leading forum on quantitative evaluation and verification of computer systems and networks. QEST 2021 is the 18th conference in the series.

Scientific areas of interest include:

• Quantitative specification methods.
• Stochastic and non-deterministic models and metrics for performance, reliability, safety, correctness, and security.
• New algorithms for the analysis or simulation of stochastic, probabilistic and non-deterministic models.
• As a recent emphasis, application of data-driven, machine learning techniques for the quantitative evaluation and verification of systems, in particular for safety-critical applications (learning for safety, as well as safe learning).
• Case studies that highlight the role of quantitative specification, modelling and evaluation in the design of systems. Systems of interest include computer hardware and software architectures, communication systems, cyber-physical systems, infrastructural systems, security systems and biological systems.
• Papers that describe novel tools to support the practical application of research results in all of the above areas are also welcome.

QEST 2021 will set up a repeatability evaluation process (details below).

QEST 2021 is open to both theoretical, experimental and applicative research. The conference welcomes a diversity of modelling formalisms, programming languages and methodologies that incorporate quantitative aspects such as probabilities, temporal properties, rewards and forms of non-determinism. Papers may advance empirical, simulation and analytic methods, and industrially-relevant case studies.

In QEST 2021, we plan to organize a special session under the topic "modelling and analysis in biology", comprising topics such as epidemiological systems, systems biology, biological networks, and computational biology. Contributions in this area are particularly welcome.

QEST 2021 considers three types of papers (authors will be able to specify the type of the contribution at the submission):

1. Theoretical/methodological: to advance the understanding on a topic or issue, or to describe the development and proposal of new analysis processes and techniques.
2. Application: to describe a novel application and compare it with previous results.
3. Tools: to develop new tools and the formalisms they support, with a focus on the software architecture and practical implementation and use. Tool papers must be accompanied by an artifact in the Repeatability/Artifact Evaluation.

Paper submission can be regular or short:

• Regular papers must not exceed 16 pages, excluding references, plus 4 pages for the appendix containing supporting material.
• Short papers should preferably be limited to 8 pages, also excluding references.

All submitted papers must be unpublished and not be submitted for publication elsewhere. Papers should be submitted electronically using EasyChair. Springer encourages authors to include their ORCIDs in their papers. Authors should consult Springer's authors' guidelines and use Springer's LaTeX templates for the preparation of their papers.

All accepted papers will be presented and discussed at the conference by one of the authors. The QEST 2021 proceedings will be published in the Springer LNCS series and indexed by ISI Web of Science, Scopus, ACM Digital Library, dblp, Google Scholar.

All submitted papers will be evaluated by at least three reviewers on the basis of their originality, technical quality, scientific or practical contribution to the state of the art, methodology, clarity, and adequacy of references.

Reproducibility of experimental results is crucial to foster an atmosphere of trustworthy, open, and reusable research. To improve and reward reproducibility, QEST 2021 for the first time includes a dedicated Repeatability/Artifact Evaluation (RAE). Submission of an artifact is mandatory for tool papers (both regular and short), and optional but encouraged for theoretical/methodological and application papers where it can support the results presented in the paper. Artifacts will be reviewed concurrently with the paper review process, and accepted papers with a successfully evaluated artifact will receive a badge to be shown on the published paper's title page.

Detailed guidelines for preparation and submission of artifacts will are available at this page. Exceptions to the submission guidelines may be granted by the PC chairs in cases where the tool cannot in any reasonable way be run by the RAE committee.

Please honor the suggestions received from the reviewers and submit the final paper (as a PDF and ZIP file with LaTeX sources) and a copyright form (signed by the corresponding author on behalf of all authors) on EasyChair by the deadline of July 5, 2021.

Appendices will be published as a part of the articles; the page limit is 16 pages + references + 4-page appendix for full papers, or 8 pages + references for short papers.

Please prepare the final version of your paper according to Springer's author guidelines. The guidelines and packages for LaTeX and Word can be downloaded here. Note that Springer encourages the inclusion of ORCIDs in the publication (more information).

A selection of the best full papers will be invited to submit an extended version of their work to a special issue in the ACM Transactions on Modelling and Computer Simulation (TOMACS).