298 research outputs found
10161 Abstracts Collection -- Decision Procedures in Software, Hardware and Bioware
From April 19th, 2010 to April 23rd, 2010, the Dagstuhl Seminar 10161
"Decision Procedures in Soft, Hard and Bio-ware"
was held in Schloss Dagstuhl Leibniz Center for Informatics.
During the seminar, several participants presented their current research,
and ongoing work and open problems were discussed. Abstracts of the
presentations given during the seminar as well as links to slides and links to
papers behind the presentations and papers produced as a result
of the seminar are put together in this paper. The first section describes
the seminar topics and goals in general. Links to extended abstracts or
full papers are provided, if available
Using ACL2 to Verify Loop Pipelining in Behavioral Synthesis
Behavioral synthesis involves compiling an Electronic System-Level (ESL)
design into its Register-Transfer Level (RTL) implementation. Loop pipelining
is one of the most critical and complex transformations employed in behavioral
synthesis. Certifying the loop pipelining algorithm is challenging because
there is a huge semantic gap between the input sequential design and the output
pipelined implementation making it infeasible to verify their equivalence with
automated sequential equivalence checking techniques. We discuss our ongoing
effort using ACL2 to certify loop pipelining transformation. The completion of
the proof is work in progress. However, some of the insights developed so far
may already be of value to the ACL2 community. In particular, we discuss the
key invariant we formalized, which is very different from that used in most
pipeline proofs. We discuss the needs for this invariant, its formalization in
ACL2, and our envisioned proof using the invariant. We also discuss some
trade-offs, challenges, and insights developed in course of the project.Comment: In Proceedings ACL2 2014, arXiv:1406.123
On the non-termination of MDG-based abstract state enumeration
AbstractMultiway decision graphs are a new class of decision graphs for representing abstract states machines. This yields a new verification technique that can deal with the data-width problem by using abstract sorts and uninterpreted functions to represent data value and data operations, respectively. However, in many cases, it may suffer from the non-termination of the state enumeration procedure. This paper presents a novel approach to solving the non-termination problem when the generated set of states, even infinite, represents a structured domain where terms (states) share certain repetitive patterns. The approach is based on the schematization method developed by Chen and Hsiang, namely ρ-terms. Schematization provides a suitable formalism for finitely manipulating infinite sets of terms. We illustrate the effectiveness of our method by several examples
Model checking for a first-order temporal logic using multiway decision graphs
Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal
PASDA: A Partition-based Semantic Differencing Approach with Best Effort Classification of Undecided Cases
Equivalence checking is used to verify whether two programs produce
equivalent outputs when given equivalent inputs. Research in this field mainly
focused on improving equivalence checking accuracy and runtime performance.
However, for program pairs that cannot be proven to be either equivalent or
non-equivalent, existing approaches only report a classification result of
"unknown", which provides no information regarding the programs'
non-/equivalence.
In this paper, we introduce PASDA, our partition-based semantic differencing
approach with best effort classification of undecided cases. While PASDA aims
to formally prove non-/equivalence of analyzed program pairs using a variant of
differential symbolic execution, its main novelty lies in its handling of cases
for which no formal non-/equivalence proof can be found. For such cases, PASDA
provides a best effort equivalence classification based on a set of
classification heuristics.
We evaluated PASDA with an existing benchmark consisting of 141
non-/equivalent program pairs. PASDA correctly classified 61-74% of these cases
at timeouts from 10 seconds to 3600 seconds. Thus, PASDA achieved equivalence
checking accuracies that are 3-7% higher than the best results achieved by
three existing tools. Furthermore, PASDA's best effort classifications were
correct for 70-75% of equivalent and 55-85% of non-equivalent cases across the
different timeouts
CBR and MBR techniques: review for an application in the emergencies domain
The purpose of this document is to provide an in-depth analysis of current reasoning engine practice and the integration strategies of Case Based Reasoning and Model Based Reasoning that will be used in the design and development of the RIMSAT system.
RIMSAT (Remote Intelligent Management Support and Training) is a European Commission funded project designed to:
a.. Provide an innovative, 'intelligent', knowledge based solution aimed at improving the quality of critical decisions
b.. Enhance the competencies and responsiveness of individuals and organisations involved in highly complex, safety critical incidents - irrespective of their location.
In other words, RIMSAT aims to design and implement a decision support system that using Case Base Reasoning as well as Model Base Reasoning technology is applied in the management of emergency situations.
This document is part of a deliverable for RIMSAT project, and although it has been done in close contact with the requirements of the project, it provides an overview wide enough for providing a state of the art in integration strategies between CBR and MBR technologies.Postprint (published version
Disproving in First-Order Logic with Definitions, Arithmetic and Finite Domains
This thesis explores several methods which enable a first-order
reasoner to conclude satisfiability of a formula modulo an
arithmetic theory. The most general method requires restricting
certain quantifiers to range over finite sets; such assumptions
are common in the software verification setting. In addition, the
use of first-order reasoning allows for an implicit
representation of those finite sets, which can avoid
scalability problems that affect other quantified reasoning
methods. These new techniques form a useful complement to
existing methods that are primarily aimed at proving validity.
The Superposition calculus for hierarchic theory combinations
provides a basis for reasoning modulo theories in a first-order
setting. The recent account of ‘weak abstraction’ and related
improvements make an mplementation of the calculus practical.
Also, for several logical theories of interest Superposition is
an effective decision procedure for the quantifier free fragment.
The first contribution is an implementation of that calculus
(Beagle), including an optimized implementation of Cooper’s
algorithm for quantifier elimination in the theory of linear
integer arithmetic. This includes a novel means of extracting
values
for quantified variables in satisfiable integer problems. Beagle
won an efficiency award at CADE Automated theorem prover System
Competition (CASC)-J7, and won the arithmetic non-theorem
category at CASC-25. This implementation is the start point for
solving the ‘disproving with theories’ problem.
Some hypotheses can be disproved by showing that, together with
axioms the hypothesis is unsatisfiable. Often this is relative to
other axioms that enrich a base theory by defining new functions.
In that case, the disproof is contingent on the satisfiability of
the enrichment.
Satisfiability in this context is undecidable. Instead, general
characterizations of definition formulas, which do not alter the
satisfiability status of the main axioms, are given. These
general criteria apply to recursive definitions, definitions over
lists, and to arrays. This allows proving some non-theorems which
are otherwise intractable, and justifies similar disproofs of
non-linear arithmetic formulas.
When the hypothesis is contingently true, disproof requires
proving existence of
a model. If the Superposition calculus saturates a clause set,
then a model exists,
but only when the clause set satisfies a completeness criterion.
This requires each
instance of an uninterpreted, theory-sorted term to have a
definition in terms of
theory symbols.
The second contribution is a procedure that creates such
definitions, given that a subset of quantifiers range over finite
sets. Definitions are produced in a counter-example driven way
via a sequence of over and under approximations to the clause
set. Two descriptions of the method are given: the first uses the
component solver modularly, but has an inefficient
counter-example heuristic. The second is more general, correcting
many of the inefficiencies of the first, yet it requires tracking
clauses through a proof. This latter method is shown to apply
also to lists and to problems with unbounded quantifiers.
Together, these tools give new ways for applying successful
first-order reasoning methods to problems involving interpreted
theories
Integrating MDG variable ordering in a VHDL-MDG design verification system
Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal
Proceedings of the 21st Conference on Formal Methods in Computer-Aided Design – FMCAD 2021
The Conference on Formal Methods in Computer-Aided Design (FMCAD) is an annual conference on the theory and applications of formal methods in hardware and system verification. FMCAD provides a leading forum to researchers in academia and industry for presenting and discussing groundbreaking methods, technologies, theoretical results, and tools for reasoning formally about computing systems. FMCAD covers formal aspects of computer-aided system design including verification, specification, synthesis, and testing
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