Model checking agent programming languages

In this paper we describe a verification system for multi-agent programs. This is the first comprehensive approach to the verification of programs developed using programming languages based on the BDI (belief-desire-intention) model of agency. In particular, we have developed a specific layer of abstraction, sitting between the underlying verification system and the agent programming language, that maps the semantics of agent programs into the relevant model-checking framework. Crucially, this abstraction layer is both flexible and extensible; not only can a variety of different agent programming languages be implemented and verified, but even heterogeneous multi-agent programs can be captured semantically. In addition to describing this layer, and the semantic mapping inherent within it, we describe how the underlying model-checker is driven and how agent properties are checked. We also present several examples showing how the system can be used. As this is the first system of its kind, it is relatively slow, so we also indicate further work that needs to be tackled to improve performance.     

The use of energy windowing to discriminate SNM from NORM in radiation portal monitors

Energy windowing is an algorithmic alarm method that can be applied to plastic scintillator-based radiation portal monitor (RPM) systems to improve operational sensitivity to certain threat sources while reducing the alarm rates from naturally occurring radioactive material. Various implementations of energy windowing have been tested and documented by industry and at Pacific Northwest National Laboratory, and are available in commercial RPMs built by several manufacturers. Moreover, energy windowing is being used in many deployed RPMs to reduce nuisance alarms and improve operational sensitivity during the screening of cargo. This paper describes energy windowing algorithms and demonstrates how these algorithms succeed when applied to “controlled” experimental measurements and “real world” vehicle traffic data.     

Explosions and impacts

This paper was prepared in response to being awarded the Hypervelocity Impact Society's Distinguished Scientist Award at HVIS 2003 held in Noordwijk, The Netherlands. It is traditional that the paper associated with the HVIS Distinguished Scientist Award is a retrospective on the recipient's career. This paper is in that tradition.     

Naive Beliefs in Baseball: Systematic Distortion in Perceived Time of Apex for Fly Balls.

When fielders catch fly balls they use geometric properties to optically maintain control over the ball. The strategy provides ongoing guidance without indicating precise positional information concerning where the ball is located in space. Here, the authors show that observers have striking misconceptions about what the motion of projectiles should look like from various perspectives and that they estimate when the physical apex of a fly ball occurs to be far later than actual, irrespective of baseball experience. Their estimations are consistent with the highest point they are looking at as the ball approaches, not with the physical apex. These findings introduce a new and robust effect in intuitive perception in which people confuse their perceptual perspective with the physical situation that they mentally represent. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparing Abstraction Refinement Algorithms

We present a generic algorithm that provides a unifying scheme for the comparison of abstraction refinement algorithms. It is centered around the notion of refinement cue which generalizes counterexamples. It is demonstrated how the essential features of several refinement algorithms can be captured as instances.We argue that the generic algorithm does not limit the completeness of instances, and show that the proposed generalization of counterexamples is necessary for completeness — thus addressing a shortcoming of more limited notions of counterexample-guided refinement.     

Robust and Rapid Generation of Animated Faces from Video Images: A Model-Based Modeling Approach

We have developed an easy-to-use and cost-effective system to construct textured 3D animated face models from videos with minimal user interaction. This is a particularly challenging task for faces due to a lack of prominent textures. We develop a robust system by following a model-based approach: we make full use of generic knowledge of faces in head motion determination, head tracking, model fitting, and multiple-view bundle adjustment. Our system first takes, with an ordinary video camera, images of a face of a person sitting in front of the camera turning their head from one side to the other. After five manual clicks on two images to indicate the position of the eye corners, nose tip and mouth corners, the system automatically generates a realistic looking 3D human head model that can be animated immediately (different poses, facial expressions and talking). A user, with a PC and a video camera, can use our system to generate his/her face model in a few minutes. The face model can then be imported in his/her favorite game, and the user sees themselves and their friends take part in the game they are playing. We have demonstrated the system on a laptop computer live at many events, and constructed face models for hundreds of people. It works robustly under various environment settings.     

Multiwavelength laser action of Nd:YAlO3 single crystals grown by the laser heated pedestal growth method

We describe the growth of high quality transparent fibers of pure and Nd-doped YAlO₃ from unreacted pedestals (green rods) by the laser heated pedestal growth technique. The X-ray diffraction analysis shows that the fibers are monocrystalline, with a distorted Pnma perovskite structure and grow along 0 1 0 direction (b axis). In this work, multi-wavelength laser action is demonstrated for these fibers in the two main laser channels of Nd³⁺ ions. In the ⁴F_3/2 → ⁴I_11/2 laser transition, low threshold multi-wavelength laser emission is obtained at wavelengths of 1065, 1073 and 1081 nm. Additionally, for the first time in LHPG grown YAlO₃ fibers, laser action in the ⁴F_3/2 → ⁴I_13/2 transition is demonstrated at a wavelength of 1341 nm.     

Oil Spill Dispersant Effectiveness Protocol. I: Impact of Operational Variables

The current U.S. Environmental Protection Agency protocol for testing the effectiveness of dispersants, the swirling flask test, has been found to give widely varying results in the hands of different testing laboratories. The sources of the ambiguities in the test were determined by considering several options in a rigorous systematic fashion. Options considered were variability among three operators and the variability and limitations of three analytical instruments in establishing a calibration curve for oil/dispersant mixtures. Other options included flask type, impact of operational variables (rotational speed, mixing time, settling time, and oil:dispersant ratio), development of a revised procedure for dispersant effectiveness, reproducibility and repeatability of the revised procedure, and development of selection criteria for screening of dispersants. A redesign of the test flask, which is characterized by having baffles with a stopcock at the bottom for sample collection, was deemed necessary to accomplish reproducibility within operator and between operators. The results indicated that the baffled flask provided a total coefficient of variation (variations within operator and between operators) less than 11% compared to above 100% in some cases for the swirling flask.     

Oil Spill Dispersant Effectiveness Protocol. II: Performance of Revised Protocol

The current U.S. Environmental Protection Agency (EPA) protocol for testing the effectiveness of dispersants for use in treating oil spills on the open water, the swirling flask test (SFT), has been found to give widely varying results in the hands of different testing laboratories. Part I addressed the sources of the ambiguities in the EPA SFT and the development of a new test referred to as the baffled flask test (BFT). In this part of the series, further experiments were conducted for estimating the repeatability of three operators in determining the effectiveness of 18 dispersants by both the EPA SFT and the BFT methods. Overall statistical analysis of the results indicated that the coefficient of variation by the BFT was only 7.8% compared to 21.9% for the EPA SFT. The mean percent effectiveness of the EPA SFT was only 19.7% as compared to 64.6% for the BFT. Proposed selection criteria for screening of dispersants for listing on the National Contingency Plan Product Schedule have been developed.     

Twelve-Week Outcomes From an Investigation of High-Dose Nicotine Patch Therapy for Heavy Smokers With a Past History of Alcohol Dependence.

This study reports findings from an investigation of the efficacy of high-dose nicotine patch (NP) therapy for heavy smokers with a past history of alcohol dependence. One hundred thirty participants were randomly assigned to 42 mg or 21 mg of transdermal nicotine for 4 weeks, followed by an 8-week dose titration. Follow-up assessments were conducted at 4 and 12 weeks. Differences between dose conditions were nonsignificant, although unexpectedly, outcomes favored participants in the 21-mg NP condition. Nicotine abstinence at follow-up was related to longer length of alcohol abstinence at time of enrollment. Future research should investigate ways to improve smoking quit rates in this population, including more frequent counseling sessions and/or other pharmacotherapies. These investigations should focus primarily on smokers in early alcohol recovery. (PsycINFO Database Record (c) 2010 APA, all rights reserved)