Title
An SMT-based approach to weak controllability for disjunctive temporal problems with uncertainty
Abstract
The framework of temporal problems with uncertainty (TPU) is useful to express temporal constraints over a set of activities subject to uncertain (and uncontrollable) duration. In this work, we focus on the most general class of TPU, namely disjunctive TPU (DTPU), and consider the case of weak controllability, that allows one to model problems arising in practical scenarios (e.g. on-line scheduling).We first tackle the decision problem, i.e. whether there exists a schedule of the activities that, depending on the uncertainty, satisfies all the constraints. We propose a logical approach, based on the reduction to a problem of Satisfiability Modulo Theories (SMT), in the theory of Linear Real Arithmetic with Quantifiers. This results in the first implemented solver for weak controllability of DTPUs.Then, we tackle the problem of synthesizing control strategies for scheduling the activities. We focus on strategies that are amenable for efficient execution. We prove that linear strategies are not always sufficient, even in the sub-case of simple TPU (STPU), while piecewise-linear strategies, that are multiple conditionally-applied linear strategies, are always sufficient. We present several algorithms for the synthesis of linear and piecewise-linear strategies, in case of STPU and of DTPU.All the algorithms are implemented on top of SMT solvers. We provide experimental evidence of the scalability of the proposed techniques, with dramatic speed-ups in strategy execution compared to on-line reasoning.
Year
DOI
Venue
2015
10.1016/j.artint.2015.03.002
Artif. Intell.
Keywords
Field
DocType
Weak controllability,Temporal problems,Satisfiability modulo theory,Strategy synthesis
Discrete mathematics,Decision problem,Logical approach,Mathematical optimization,Controllability,Existential quantification,Scheduling (computing),Solver,Mathematics,Scalability,Satisfiability modulo theories
Journal
Volume
Issue
ISSN
224
C
0004-3702
Citations 
PageRank 
References 
5
0.44
30
Authors
3
Name
Order
Citations
PageRank
Alessandro Cimatti15064323.15
Andrea Micheli219014.08
Marco Roveri3171.47