Steve Schaffer

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GameBots [1] is a virtual reality platform that allows the creation and evaluation of intelligent agents that interact with a rich 3D continuous dynamic environment. As opposed to previous test beds that focus on a single task and environment (such as soccer simulation [4]), GameBots does not define a single benchmark task. Instead, the GameBots platform(More)
Biomarkers of trans-fatty acid consumption have been associated with increased risks of breast and colon cancer, although no studies have examined their associations with prostate cancer risk. Using data from the beta-Carotene and Retinol Efficacy Trial, this nested case-control study examined the relationships between serum phospholipid trans-fatty acids(More)
To examine the association between breast cancer risk and the fatty acid composition of phospholipids in prediagnostic serum samples. We analyzed the fatty acid composition in 130 incident postmenopausal breast cancer cases and 257 matched controls nested within the β-Carotene and Retinol Efficacy Trial Cohort. The fatty acid composition was measured by gas(More)
This paper describes how continuous planning and execution techniques can be used to perform intelligent decision-making for an autonomous Mars rover. The resulting system coordinates low-level rover functionality to achieve science objectives while respecting rover resource and operation constraints. It provides capabilities for schedule generation,(More)
A method based on differential geometric control theory is presented intended to provide insight into how the nodes of a power network can affect each other. In this preliminary report, we consider a simple model of a power system derived from singular perturbation of the power flow equations. It is shown that such a model is accessible, and that for simple(More)
We are developing onboard planning and execution technologies to provide robust and opportunistic mission operations for a future Titan aerobot. Aerobot have the potential for collecting a vast amount of high priority science data. However, to be effective, an aerobot must address several challenges including communication constraints, extended periods(More)
Several viral transport experiments were conducted in a model aquifer 1 m long, using bacteriophages MS2 and phiX174 at various pH (4.6 to 8.3) conditions, to increase our understanding of virus behavior in ground water. The results indicate the existence of a critical pH at which the virus behavior changes abruptly. This is supported by data from field and(More)
This paper describes how continuous planning and execution techniques can be used to perform intelligent decision-making for an autonomous Mars rover. The resulting system coordinates low-level rover functionality to achieve science targets while respecting rover resource and operation constraints. Provided capabilities include initial schedule generation,(More)
Intelligent behavior for robotic agents requires a careful balance of fast reactions and deliberate consideration of long-term ramifications. The need for this balance is particularly acute in space applications, where hostile environments demand fast reactions, and remote locations dictate careful management of consumables that cannot be replenished.(More)