Sarah L. Hickmott

sarah.hickmott@rmit.edu.au

Intelligent Systems (Agents Group)
School of CS & IT
RMIT Univeristy, City Campus
Building 14 Level 8 Office 7C

GPO BOX 2476
Melbourne, VIC 3001
Australia

Current Research

BLOCKS for Climate Change Adaptation
- Bulding Large, Open, Complex, Knowledge-based Simulations (BLOCKS)
- Focus on using agent-based simulation to explore human adaptation to climate change and human response to extreme weather events
- e.g., See Project Page for ARC DP1093290: An Extensible Agent-Based Framework for Exploring Climate Change Adaptation
- For possible undergrad student projects see here. For honours and PhD possibilities related to this work contact me directly.
And still thinking about AI Planning and Petri net unfolding...

Papers

Optimality properties of planning via Petri net unfolding: A formal analysis. Sarah L. Hickmott, Sebastian Sardina. Alfonso Gerevini and Adele Howe, editors, Proceedings of the International Conference on Automated Planning and Scheduling (ICAPS), pages 170-177, Thessaloniki, Greece, September 2009. AAAI Press. [pdf]
An Optimality Principle for Concurrent Systems. Langford B. White, Sarah L. Hickmott. Australasian Conference on Artificial Intelligence 2008: 128-137 [pdf]
Directed Unfolding of Petri Nets. Blai Bonet, Patrik Haslum, Sarah Hickmott, Sylvie Thiebaux. LNCS Transactions on Petri Nets and other models of concurrency (ToPNoC). [pdf]
Planning via Petri Net Unfolding. Sarah L. Hickmott, Jussi Rintanen, Sylvie Thiebaux, and Langford B. White. In Proc. of the 20th Int. Joint Conf. on Aritifical Intelligence (IJCAI-07).[pdf]
Concurrent Planning using Petri Net Unfoldings. S. Hickmott In Proceedings of 16th International Conference on Automated Planning and Scheduling (ICAPS-06) Doctoral Consortium.
Reduced MDP Representation of a Logistical Planning Problem Using Petri-Nets. Sanjeev Naguleswaran, Sarah L. Hickmott, Langford B. White. In Proceedings of Australian Conference on Artificial Intelligence 2005.

Tutorials

Petri Nets and Their Relation to Planning, presented with Blai Bonet, Patrik Haslum, Sylvie Thiebaux and Stefan Edelkamp, at ICAPS 2009

PhD Thesis (University of Adelaide & National ICT Australia, 2008):

Directed Unfolding - Reachability Analysis of Concurrent Systems and Application to Automated Planning.[pdf]

This thesis exploits the relationship between the formal reachability problem for discrete event systems, and the automated planning problem, via Petri net unfolding, which is an attractive analysis method for highly concurrent systems as it facilitates reasoning about independent sub-problems. The first contribution of this thesis is the theory of directed unfolding: controlling the unfolding process with heuristically-informed strategies, for the purpose of optimality and increased efficiency. The second contribution is the application of directed unfolding to automated planning. Planning via directed unfolding offers a approach to planning which lies between state-space planning and traditional partial-order planning approaches, with respect to the level of commitment made during plan refinement. It facilitates forward partial order planning, guided by state-based heuristic. Our suite of planners based on directed unfolding can perform optimal and suboptimal classical planning subject to arbitrary action costs, optimal temporal planning with respect to arbitrary action durations, and address probabilistic planning via replanning for the most likely path. Empirical results reveal directed unfolding is competitive with current state of the art automated planning systems, and can solve Petri net reachability problems beyond the reach of the original "blind" unfolding technique.

Korla, Xinjiang, PRC. PHOTO BY TOM CLIFF