331 research outputs found
Model checking embedded system designs
We survey the basic principles behind the application of model checking to controller verification and synthesis. A promising development is the area of guided model checking, in which the state space search strategy of the model checking algorithm can be influenced to visit more interesting sets of states first. In particular, we discuss how model checking can be combined with heuristic cost functions to guide search strategies. Finally, we list a number of current research developments, especially in the area of reachability analysis for optimal control and related issues
A Novel SAT-Based Approach to the Task Graph Cost-Optimal Scheduling Problem
The Task Graph Cost-Optimal Scheduling Problem consists in scheduling a certain number of interdependent tasks onto a set of heterogeneous processors (characterized by idle and running rates per time unit), minimizing the cost of the entire process. This paper provides a novel formulation for this scheduling puzzle, in which an optimal solution is computed through a sequence of Binate Covering Problems, hinged within a Bounded Model Checking paradigm. In this approach, each covering instance, providing a min-cost trace for a given schedule depth, can be solved with several strategies, resorting to Minimum-Cost Satisfiability solvers or Pseudo-Boolean Optimization tools. Unfortunately, all direct resolution methods show very low efficiency and scalability. As a consequence, we introduce a specialized method to solve the same sequence of problems, based on a traditional all-solution SAT solver. This approach follows the "circuit cofactoring" strategy, as it exploits a powerful technique to capture a large set of solutions for any new SAT counter-example. The overall method is completed with a branch-and-bound heuristic which evaluates lower and upper bounds of the schedule length, to reduce the state space that has to be visited. Our results show that the proposed strategy significantly improves the blind binate covering schema, and it outperforms general purpose state-of-the-art tool
Constraint-Based Heuristic On-line Test Generation from Non-deterministic I/O EFSMs
We are investigating on-line model-based test generation from
non-deterministic output-observable Input/Output Extended Finite State Machine
(I/O EFSM) models of Systems Under Test (SUTs). We propose a novel
constraint-based heuristic approach (Heuristic Reactive Planning Tester (xRPT))
for on-line conformance testing non-deterministic SUTs. An indicative feature
of xRPT is the capability of making reasonable decisions for achieving the test
goals in the on-line testing process by using the results of off-line bounded
static reachability analysis based on the SUT model and test goal
specification. We present xRPT in detail and make performance comparison with
other existing search strategies and approaches on examples with varying
complexity.Comment: In Proceedings MBT 2012, arXiv:1202.582
Verification and Parameter Synthesis for Real-Time Programs using Refinement of Trace Abstraction
We address the safety verification and synthesis problems for real-time
systems. We introduce real-time programs that are made of instructions that can
perform assignments to discrete and real-valued variables. They are general
enough to capture interesting classes of timed systems such as timed automata,
stopwatch automata, time(d) Petri nets and hybrid automata.
We propose a semi-algorithm using refinement of trace abstractions to solve
both the reachability verification problem and the parameter synthesis problem
for real-time programs.
All of the algorithms proposed have been implemented and we have conducted a
series of experiments, comparing the performance of our new approach to
state-of-the-art tools in classical reachability, robustness analysis and
parameter synthesis for timed systems. We show that our new method provides
solutions to problems which are unsolvable by the current state-of-the-art
tools
TarTar: A Timed Automata Repair Tool
We present TarTar, an automatic repair analysis tool that, given a timed
diagnostic trace (TDT) obtained during the model checking of a timed automaton
model, suggests possible syntactic repairs of the analyzed model. The suggested
repairs include modified values for clock bounds in location invariants and
transition guards, adding or removing clock resets, etc. The proposed repairs
are guaranteed to eliminate executability of the given TDT, while preserving
the overall functional behavior of the system. We give insights into the design
and architecture of TarTar, and show that it can successfully repair 69% of the
seeded errors in system models taken from a diverse suite of case studies.Comment: 15 pages, 7 figure
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