Exploiting Target Enlargement and Dynamic Abstraction within Mixed BDD and SAT Invariant Checking

In this paper, we propose a methodology to make Binary Decision Diagrams (BDDs) and Boolean Satisfiability (SAT) Solvers cooperate. The underlying idea is simple: We start a verification task with BDDs, we go on with them as long as the problem remains of manageable size, then we switch to SAT, without losing the work done on the BDD domain. We propose target enlargement as an attempt to bring some of the advantages of state set manipulation from BDDs to SAT-based verification. We first, "enlarge" initial and target state sets of a given verification problem by affordable BDD manipulations. This step is carried on with a few breadth-first steps of traversal, or with what we call high-density dynamic abstraction, i.e., a new technique to collect under-approximate reachable state sets. Then, we perform SAT-based verification with the newly computed "enlarged" sets. We experimentally test our methodology within an industrial environment, the Intel BOolean VErifier BOVE. Preliminary results on standard benchmarks (the ISCAS'89, ISCAS'89--addendum, and VIS suites), and industrial ones (the IBM Formal Verification Benchmark Library) are provided. Results show interesting improvements over state-of-the-art techniques: We could decrease CPU time up to a 5x factor, when performing verification with the same depth, or we could increase the verification depth up to 30%, when performing verification within the same time limi

Exploiting Target Enlargement and Dynamic Abstraction within Mixed BDD and SAT Invariant Checking

In this paper, we propose a methodology to make Binary Decision Diagrams (BDDs) and Boolean Satisfiability (SAT) Solvers cooperate. The underlying idea is simple: We start a verification task with BDDs, we go on with them as long as the problem remains of manageable size, then we switch to SAT, without losing the work done on the BDD domain. We propose target enlargement as an attempt to bring some of the advantages of state set manipulation from BDDs to SAT-based verification. We first, "enlarge" initial and target state sets of a given verification problem by affordable BDD manipulations. This step is carried on with a few breadth-first steps of traversal, or with what we call high-density dynamic abstraction, i.e., a new technique to collect under-approximate reachable state sets. Then, we perform SAT-based verification with the newly computed "enlarged" sets. We experimentally test our methodology within an industrial environment, the Intel BOolean VErifier BOVE. Preliminary results on standard benchmarks (the ISCAS'89, ISCAS'89--addendum, and VIS suites), and industrial ones (the IBM Formal Verification Benchmark Library) are provided. Results show interesting improvements over state-of-the-art techniques: We could decrease CPU time up to a 5x factor, when performing verification with the same depth, or we could increase the verification depth up to 30%, when performing verification within the same time limit

Multi-Agent Systems

A multi-agent system (MAS) is a system composed of multiple interacting intelligent agents. Multi-agent systems can be used to solve problems which are difficult or impossible for an individual agent or monolithic system to solve. Agent systems are open and extensible systems that allow for the deployment of autonomous and proactive software components. Multi-agent systems have been brought up and used in several application domains

Safety and Reliability - Safe Societies in a Changing World

The contributions cover a wide range of methodologies and application areas for safety and reliability that contribute to safe societies in a changing world. These methodologies and applications include: - foundations of risk and reliability assessment and management - mathematical methods in reliability and safety - risk assessment - risk management - system reliability - uncertainty analysis - digitalization and big data - prognostics and system health management - occupational safety - accident and incident modeling - maintenance modeling and applications - simulation for safety and reliability analysis - dynamic risk and barrier management - organizational factors and safety culture - human factors and human reliability - resilience engineering - structural reliability - natural hazards - security - economic analysis in risk managemen

The drivers of Corporate Social Responsibility in the supply chain. A case study.

Purpose: The paper studies the way in which a SME integrates CSR into its corporate strategy, the practices it puts in place and how its CSR strategies reflect on its suppliers and customers relations. Methodology/Research limitations: A qualitative case study methodology is used. The use of a single case study limits the generalizing capacity of these findings. Findings: The entrepreneur’s ethical beliefs and value system play a fundamental role in shaping sustainable corporate strategy. Furthermore, the type of competitive strategy selected based on innovation, quality and responsibility clearly emerges both in terms of well defined management procedures and supply chain relations as a whole aimed at involving partners in the process of sustainable innovation. Originality/value: The paper presents a SME that has devised an original innovative business model. The study pivots on the issues of innovation and eco-sustainability in a context of drivers for CRS and business ethics. These values are considered fundamental at International level; the United Nations has declared 2011 the “International Year of Forestry”