1,502 research outputs found
Formal and Informal Methods for Multi-Core Design Space Exploration
We propose a tool-supported methodology for design-space exploration for
embedded systems. It provides means to define high-level models of applications
and multi-processor architectures and evaluate the performance of different
deployment (mapping, scheduling) strategies while taking uncertainty into
account. We argue that this extension of the scope of formal verification is
important for the viability of the domain.Comment: In Proceedings QAPL 2014, arXiv:1406.156
Optimal Reachability in Divergent Weighted Timed Games
Weighted timed games are played by two players on a timed automaton equipped
with weights: one player wants to minimise the accumulated weight while
reaching a target, while the other has an opposite objective. Used in a
reactive synthesis perspective, this quantitative extension of timed games
allows one to measure the quality of controllers. Weighted timed games are
notoriously difficult and quickly undecidable, even when restricted to
non-negative weights. Decidability results exist for subclasses of one-clock
games, and for a subclass with non-negative weights defined by a semantical
restriction on the weights of cycles. In this work, we introduce the class of
divergent weighted timed games as a generalisation of this semantical
restriction to arbitrary weights. We show how to compute their optimal value,
yielding the first decidable class of weighted timed games with negative
weights and an arbitrary number of clocks. In addition, we prove that
divergence can be decided in polynomial space. Last, we prove that for untimed
games, this restriction yields a class of games for which the value can be
computed in polynomial time
The Reach-Avoid Problem for Constant-Rate Multi-Mode Systems
A constant-rate multi-mode system is a hybrid system that can switch freely
among a finite set of modes, and whose dynamics is specified by a finite number
of real-valued variables with mode-dependent constant rates. Alur, Wojtczak,
and Trivedi have shown that reachability problems for constant-rate multi-mode
systems for open and convex safety sets can be solved in polynomial time. In
this paper, we study the reachability problem for non-convex state spaces and
show that this problem is in general undecidable. We recover decidability by
making certain assumptions about the safety set. We present a new algorithm to
solve this problem and compare its performance with the popular sampling based
algorithm rapidly-exploring random tree (RRT) as implemented in the Open Motion
Planning Library (OMPL).Comment: 26 page
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