Planning & Scheduling
Planning with State Uncertainty via Contingency Planning and Execution Monitoring
Wang, Minlue (University of Birmingham) | Dearden, Richard (University of Birmingham)
An example is a Mars rover: The major problem with applying POMDP approaches to thanks to low-level control and obstacle avoidance, rovers realistic planning problems like the Mars rovers is the sheer can be expected to reach their destinations reliably, and can size of the problems. Using point-based approximations and collect and communicate data, but they do not know in advance structured representations similar to those used in classical which science targets are interesting and hence will planning (Poupart 2005), problems with tens of millions provide valuable data. Similarly, robots performing tasks of states can be solved approximately, but even that corresponds such as security or cognitive assistance are generally able to to a classical planning problem with only 25 binary navigate reliably, but use unreliable vision algorithms to detect variables, which is a quite small problem by the standards the people and objects with which they are supposed of classical deterministic planning. The alternative we propose to interact. Following Besse and Chaib-draa (2009), we in this paper is to construct a series of classical deterministic will refer to problems with deterministic actions but stochastic planning problems from the quasi-deterministic observations as quasi-deterministic problems, which differ problem. By solving each of these deterministic problems from Deterministic-POMDPs (DET-POMDPS) (Bonet we construct a contingent plan--one that contains branches 2009) by taking into account of uncertainty from observation to be chosen between at run-time.
Does Representation Matter in the Planning Competition?
Riddle, Patricia J. (University of Auckland) | Holte, Robert C. (University of Alberta) | Barley, Michael W. (University of Auckland)
This paper explores six different representations of the BlocksWorld Domain. It compares the results of seven planners run on these representations. It shows that the rankings for the International Planning Competition, using the non-satisficing scoring function, would change for every representation.
Automatic Synthesis of Temporal Invariants
Bernardini, Sara (London Knowledge Lab) | Smith, David E. (NASA Ames Research Center)
We present a technique for automatically extracting temporal mutual exclusion invariants from PDDL2.2 planning instances. Our technique builds on other approaches to invariant synthesis presented in the literature, but departs from their limited focus on instantaneous discrete actions by addressing temporal and numeric domains. To deal with time, we formulate invariance conditions that account for both the entire structure of the operators (including the conditions, rather than just the effects) and the possible interactions between operators.
Awareness in Mixed Initiative Planning
Gianni, Mario (Sapienza University of Rome) | Papadakis, Panagiotis (Sapienza University of Rome) | Pirri, Fiora (Sapienza University of Rome) | Pizzoli, Matia (Sapienza University of Rome)
For tasks that need to be accomplished in unconstrained environments, as in the case of Urban Search and Rescue (USAR), human-robot collaboration is considered as an indispensable component. Collaboration is based on accurate models of robot and human perception consistent with one another, so that exchange of information critical to the accomplishment of a task is performed efficiently and in a simplified fashion to minimize the interaction overhead. In this paper, we highlight the features of a human-robot team, i.e. how robot perception may be combined with human perception based on a task-driven direction for USAR. We elaborate on the design of the components of a mixed-initiative system wherein a task assigned to the robot is planned and executed jointly with the human operator as a result of their interaction. Our description is solidified by demonstrating the application of mixed-initiative planning in a number of examples related to the morphological adaptation of the rescue robot.
Tool Use Learning in Robots
Brown, Solly (University of New South Wales) | Sammut, Claude (University of New South Wales)
Learning to use an object as a tool requires understanding what goals it helps to achieve, the properties of the tool that make it useful and how the tool must be manipulated to achieve the goal. We present a method that allows a robot to learn about objects in this way and thereby employ them as tools. An initial hypothesis for an action model of tool use is created by observing another agent accomplishing a task using a tool. The robot then refines its hypothesis by active learning, generating new experiments and observing the outcomes. Hypotheses are updated using Inductive Logic Programming. One of the novel aspects of this work is the method used to select experiments so that the search through the hypothesis space is minimised.
Toward Resilient Human-Robot Interaction through Situation Projection for Effective Joint Action
Pearce, Adrian R. (The University of Melbourne) | Sonenberg, Liz (The University of Melbourne) | Nixon, Paddy (The University of Tasmania)
In this paper we address the design of robots that can be successful partners to humans in joint activity. The paper outlines an approach to achieving adjustable autonomy during execution- and hence to achieve resilient multi-actor joint action - based on both temporal and epistemic situation projection. The approach is based on non-deterministic planning techniques based on the situations calculus.
Improving Acquisition of Teleoreactive Logic Programs through Representation Change
Li, Nan (Carnegie Mellon University) | Stracuzzi, David J. (Sandia National Laboratories) | Langley, Pat (Arizona State University)
An important form of learning involves acquiring skills that let an agent achieve its goals. While there has been considerable work on learning in planning, most approaches have been sensitive to the representation of domain context, which hurts their generality. A learning mechanism that constructs skills effectively across different representations would suggest more robust behavior. In this paper, we present a novel approach to learning hierarchical task networks that acquires conceptual predicates as learning proceeds, making it less dependent on carefully crafted background knowledge. The representation acquisition procedure expands the system's knowledge about the world, and leads to more rapid learning. We show the effectiveness of the approach by comparing it with one that doesnot change domain representation.
Loosely Coupled Formulations for Automated Planning: An Integer Programming Perspective
Briel, Menkes Hector Louis van den, Vossen, Thomas, Kambhampati, Subbarao
We represent planning as a set of loosely coupled network flow problems, where each network corresponds to one of the state variables in the planning domain. The network nodes correspond to the state variable values and the network arcs correspond to the value transitions. The planning problem is to find a path (a sequence of actions) in each network such that, when merged, they constitute a feasible plan. In this paper we present a number of integer programming formulations that model these loosely coupled networks with varying degrees of flexibility. Since merging may introduce exponentially many ordering constraints we implement a so-called branch-and-cut algorithm, in which these constraints are dynamically generated and added to the formulation when needed. Our results are very promising, they improve upon previous planning as integer programming approaches and lay the foundation for integer programming approaches for cost optimal planning.
The Complexity of Planning Problems With Simple Causal Graphs
Giménez, Omer, Jonsson, Anders
We present three new complexity results for classes of planning problems with simple causal graphs. First, we describe a polynomial-time algorithm that uses macros to generate plans for the class 3S of planning problems with binary state variables and acyclic causal graphs. This implies that plan generation may be tractable even when a planning problem has an exponentially long minimal solution. We also prove that the problem of plan existence for planning problems with multi-valued variables and chain causal graphs is NP-hard. Finally, we show that plan existence for planning problems with binary state variables and polytree causal graphs is NP-complete.
Exploiting Subgraph Structure in Multi-Robot Path Planning
Multi-robot path planning is difficult due to the combinatorial explosion of the search space with every new robot added. Complete search of the combined state-space soon becomes intractable. In this paper we present a novel form of abstraction that allows us to plan much more efficiently. The key to this abstraction is the partitioning of the map into subgraphs of known structure with entry and exit restrictions which we can represent compactly. Planning then becomes a search in the much smaller space of subgraph configurations. Once an abstract plan is found, it can be quickly resolved into a correct (but possibly sub-optimal) concrete plan without the need for further search. We prove that this technique is sound and complete and demonstrate its practical effectiveness on a real map. A contending solution, prioritised planning, is also evaluated and shown to have similar performance albeit at the cost of completeness. The two approaches are not necessarily conflicting; we demonstrate how they can be combined into a single algorithm which outperforms either approach alone.