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Patrick W. Dymond

Possible papers associated with this exact author name in Arrow. This page groups case-insensitive exact name matches and is not a full identity disambiguation profile.

7 papers
2 author rows

Possible papers

7

IROS Conference 2014 Conference Paper

Integrating multiple soft constraints for planning practical paths

  • Jing Yang
  • Patrick W. Dymond
  • Michael Jenkin

Sampling-based algorithms are a common approach to high-dimensional real-world path planning problems. Unfortunately the solutions found using such planners are often not practical in that they do not take into account soft application-specific constraints. This paper formulates the practicality of paths based on the notion of soft constraints found in the Planning Domain Definition Language 3 (PDDL3) [21] and a range of optimization strategies are developed targeted towards user-preferred qualities by integrating soft constraints in the pre-processing, planning and post-processing phases of the sampling-based path planners. An auction-based resource allocation approach coordinates competing optimization strategies. This approach uses an adaptive bidding strategy for each optimizer and in each round the optimizer with the best predicted performance is selected. This general coordination system allows for flexibility in both the number and types of the optimizers used. Experimental validation demonstrates the effectiveness of the approach.

ICRA Conference 2011 Conference Paper

The relative power of immovable markers in topological mapping

  • Hui Wang 0068
  • Michael Jenkin
  • Patrick W. Dymond

The fundamental problem in robotic exploration and mapping of an unknown environment is answering the question 'have I been here before? ', which involves disambiguating the robot's current location from previously visited or known locations. One approach to answering this problem in embedded topological worlds is to resort to the use of an external aid that can help the robot disambiguate places. Here we investigate the power of different marker-based aids in exploring undirected topological graphs. We demonstrate that for undirected graphs, certain marker aids are insufficient, while others have powers that are sufficient to develop asymptotically optimal exploration algorithms.

IROS Conference 2010 Conference Paper

Using a string to map the world

  • Hui Wang 0068
  • Michael Jenkin
  • Patrick W. Dymond

Literature and folklore is rife with a range of oracles that have been used by explorers to explore unknown environments. But how effective are these various oracles? This paper considers the power of string and string-like oracles to map an unknown embedded topological environment. We demonstrate that for undirected graphs, even very short strings can be used to explore an unknown environment but that significant performance improvements can be found when longer strings are available.

I&C Journal 1989 Journal Article

Complexity theory of parallel time and hardware

  • Patrick W. Dymond
  • Stephen A. Cook

The parallel resources time and hardware and the complexity classes defined by them are studied using the aggregate model. The equivalence of complexity classes defined by sequential space and uniform aggregate hardware is established. Aggregate time is related to (bounded fanin) circuit depth and, similarly, aggregate hardware is related to circuit width. Interelationships between aggregate time and hardware follow as corollaries. Aggregate time is related to the sequential resource reversal. Simultaneous relationships from aggregate hardware and time to sequential space and reversal are shown (and conversely), and these are used as evidence for an “extended parallel computation thesis. ” These simultaneous relationships provide new characterizations for the simultaneous parallel complexity class NC and for the complementary class SC. The evaluation of monotone planar circuits is shown to be in NC, in fact in LOGCFL.

TCS Journal 1986 Journal Article

On nondeterminism in parallel computation

  • Patrick W. Dymond

Nondeterministic parallel complexity classes are investigated using two different nondeterministic versions of the hardware modification machine model. Differences in the effects of adding nondeterminism to parallel machines can be traced to the amount of nondeterminism available at each time step. Nondeterministic complexity classes defined by simultaneous bounds on both hardware and parallel time are also examined.

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