This book constitutes the proceedings of the 12th International Symposium on NASA Formal Methods, NFM 2020, held in Moffett Field, CA, USA, in May 2020.*

The 20 full and 5 short papers presented in this volume were carefully reviewed and selected from 62 submissions. The papers are organized in the following topical sections: learning and formal synthesis; formal methods for DNNs; high assurance systems; requirement specification and testing; validation and solvers; solvers and program analysis; verification and times systems; autonomy and other applications; and hybrid and cyber-physical systems. *The conference was held virtually due to the COVID-19 pandemic. The chapter "Verifying a Solver for Linear Mixed Integer Arithmetic in Isabelle/HOL" is available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.

Inhalt

Learning and Formal Synthesis.- From Passive to Active: Learning Timed Automata Efficiently.- Generating Correct-by-Construction Distributed Implementations from Formal Maude Designs.- Parameter Synthesis and Robustness Analysis of Rule-Based Models.- Formal Methods for DNNs.- PaRoT: A Practical Framework for Robust Deep Neural Network Training.- Simplifying Neural Networks using Formal Verification.- High Assurance Systems.- Neural Simplex Architecture.- Strengthening Deterministic Policies for POMDPs.- Benchmarking Software Model Checkers on Automotive Code.- Requirement Specification and Testing.- Automated Requirements-Based Testing of Black-Box Reactive Systems.- Formal Verification of Parallel Prefix Sum.- Specification Quality Metrics Based on Mutation and Inductive Incremental Model Checking.- Validation and Solvers.- A Validation Methodology for OCaml-to-PVS Translation.- On the Usefulness of Clause Strengthening in Parallel SAT Solving.- Solvers and Program Analysis.- Verifying a Solver for Linear Mixed Integer Arithmetic in Isabelle/HOL*.- Constraint Caching Revisited.- Per-Location Simulation.- Verification and Timed Systems.- Sampling Distributed Schedules for Resilient Space Communication.- Model Checking Timed Hyperproperties in Discrete-Time Systems.- Verifying Band Convergence for Sampled Control Systems.- Autonomy and Other Applications.- Heterogeneous Verification of an Autonomous Curiosity Rover.- Run-Time Assurance for Learning-Enabled Systems.- hpnmg: A CC++ Tool for Model Checking Hybrid Petri Nets with General Transitions.- Hybrid and Cyber-Physical Systems.- A Transformation of Hybrid Petri Nets with Stochastic Firings into a Subclass of Stochastic Hybrid Automata.- Constraining Counterexamples in Hybrid System Falsification: Penalty-Based Approaches.- Falsification of Cyber-Physical Systems with Constrained Signal Spaces.