Marco Bakera

Test your Strategy: Graphical Construction of Strategies for Connect-Four

In this paper, we present the ConnectIT tool, which uses a graphical flow graph-based representation to express strategies for playing the connect-four game. The tool allows to transfer complex knowledge about theconnect-four game itself, simple algorithmic concepts, and modern high-level component-based modeling techniques from theoretical grounds into an inspiring and practical learning experience. For proving the feasibilityof this approach, we applied the tool in a project with pupils, who had no experience in computer sciences at all. We demonstrate that solely based on intuition and knowledge about the connect-four game, the pupils wereable to build really competitive strategies.

Solving μ-Calculus Parity Games by Symbolic Planning

This paper applies symbolic planning to solve parity games equivalent to μ-calculus model checking problems. Compared to explicit algorithms, state sets are compacted during the analysis. Given that \(\mbox{\it diam}(G)\) is the diameter of the parity game graph G with node set V, for the alternation-free model checking problem with at most one fixpoint operator, the algorithm computes at most \(O(\mbox{\it diam}(G))\) partitioned images. For d alternating fixpoint operators, \(O(d \cdot \mbox{\it diam}(G) \cdot (\frac{|V|+(d-1)}{d-1})^{d-1})\) partitioned images are required in the worst case.

Game-Based Model Checking for Reliable Autonomy in Space

Autonomy is an emerging paradigm for the design and implementation of managed services and systems. Self-managed aspects frequently concern the communication of systems with their environment. Self-management subsystems are critical, they should thus be designed and implemented as high-assurance components. Here, we propose to use GEAR, a game-based model checker for the full modal mu-calculus, and derived, more user-oriented logics, as a user friendly tool that can offer automatic proofs of critical properties of such systems. Designers and engineers can interactively investigate automatically generated winning strategies resulting from the games, this way exploring the connection between the property, the system, and the proof. The benefits of the approach are illustrated on a case study that concerns the ExoMars Rover.