Huang, Xiaowei
Model Checking Probabilistic Knowledge: A PSPACE Case
Huang, Xiaowei (University of Oxford) | Kwiatkowska, Marta (University of Oxford)
Model checking probabilistic knowledge of memoryful semantics is undecidable, even for a simple formula concerning the reachability of probabilistic knowledge of a single agent. This result suggests that the usual approach of tackling undecidable model checking problems, by finding syntactic restrictions over the logic language, may not suffice. In this paper, we propose to work with an additional restriction that agent's knowledge concerns a special class of atomic propositions. A PSPACE-complete case is identified with this additional restriction, for a logic language combining LTL with limit-sure knowledge of a single agent.
Strengthening Agents Strategic Ability with Communication
Huang, Xiaowei (University of Oxford and Jinan University) | Chen, Qingliang (Jinan University) | Su, Kaile (Griffith University and Jinan University)
The current frameworks of reasoning about agents' collective strategy are either too conservative or too liberal in terms of the sharing of local information between agents. In this paper, we argue that in many cases, a suitable amount of information is required to be communicated between agents to both enforce goals and keep privacy. Several communication operators are proposed to work with an epistemic strategy logic ATLK. The complexity of model checking resulting logics is studied, and surprisingly, we found that the additional expressiveness from the communication operators comes for free.
Symbolic Model Checking Epistemic Strategy Logic
Huang, Xiaowei (The University of New South Wales) | Meyden, Ron van der (The University of New South Wales)
This paper presents a symbolic BDD-based model checking algorithm for an epistemic strategy logic with observational semantics. The logic has been shown to be more expressive than several variants of ATELand therefore the algorithm can also be used for ATEL model checking. We implement the algorithm in a model checker and apply it to an application on train control system. The performance of the algorithm is also reported, with a comparison showing improved results over a previous partially symbolic approach for ATEL model checking.
Synthesizing Strategies for Epistemic Goals by Epistemic Model Checking: An Application to Pursuit Evasion Games
Huang, Xiaowei (University of New South Wales) | Meyden, Ron van der (University of New South Wales)
The paper identifies a special case in which the complex problem of synthesis from specifications in temporal-epistemic logic can be reduced to the simpler problem of model checking such specifications. An application is given of strategy synthesis in pursuit-evasion games, where one or more pursuers with incomplete information aim to discover theexistence of an evader. Experimental results are provided to evaluate the feasibility of the approach.
Probabilistic Alternating-Time Temporal Logic of Incomplete Information and Synchronous Perfect Recall
Huang, Xiaowei (The University of New South Wales) | Su, Kaile (Griffith University, Brisbane) | Zhang, Chenyi (University of Queensland)
A probabilistic variant of ATL* logic is proposed to work with multi-player games of incomplete information and synchronous perfect recall. The semantics of the logic is settled over probabilistic interpreted system and partially observed probabilistic concurrent game structure. While unexpectedly, the model checking problem is in general undecidable even for single-group fragment, we find a fragment whose complexity is in 2-EXPTIME. The usefulness of this fragment is shown over a land search scenario.