Publications by authors named "Ryan K Williams"

This article addresses a fundamental question of multiagent knowledge distribution: what information should be sent to whom and when with the limited resources available to each agent? Communication requirements for multiagent systems can be rather high when an accurate picture of the environment and the state of other agents must be maintained. To reduce the impact of multiagent coordination on networked systems, for example, power and bandwidth, this article introduces two concepts for the partially observable Markov decision processes (POMDPs): 1) action-based constraints that yield constrained-action POMDPs (CA-POMDPs) and 2) soft probabilistic constraint satisfaction for the resulting infinite-horizon controllers. To enable constraint analysis over an infinite horizon, an unconstrained policy is first represented as a finite-state controller (FSC) and optimized with policy iteration.

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Motivated by the strong influence network rigidity has on collaborative systems, in this paper, we consider the problem of partitioning a multiagent network into two sub-teams, a bipartition, such that the resulting sub-teams are topologically rigid. In this direction, we determine the existence conditions for rigidity-preserving bipartitions, and provide an iterative algorithm that identifies such partitions in polynomial time. In particular, the relationship between rigid graph partitions and the previously identified Z-link edge structure is given, yielding a feasible direction for graph search.

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Emissions from open detonation (OD), open burning (OB), and static firing (SF) of obsolete military munitions were collected using an aerostat-lofted sampling instrument maneuvered into the plumes with remotely controlled tether winches. PM2.5, PM10, metals, volatile organic compounds (VOCs), energetics, and polyaromatic hydrocarbons (PAHs) were characterized from 121 trials of three different munitions (Composition B (hereafter, "Comp B"), V453, V548), 152 trials of five different propellants (M31A1E1, M26, SPCF, Arc 451, 452A), and 12 trials with static firing of ammonium perchlorate-containing Sparrow rocket motors.

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Alcohol consumption, a larger history of childhood parental rejection, and high prenatal androgen exposure have been linked with facilitation and high risk of recidivism in intimate partner violence (IPV) perpetrators. Participants were distributed into two groups according to their alcohol consumption scores as high (HA) and low (LA). HA presented a higher history of childhood parental rejection, prenatal masculinization (smaller 2D:4D ratio), and violence-related scores than LA IPV perpetrators.

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