263 research outputs found
The Effectiveness of the Presentation and Removal of Money as Reward and Punishment in a Paired-Associate-Constant Order Learning Task
This type of research is believed to be important because of the implications it would seem to have for educational techniques. For example, a program could be instituted at the high school level whereby students would be rewarded with money for maintaining a certain academic standard but punished by the removal of a portion of this money for dropping below that standard. This technique might, in addition to facilitating their learning, act as a motivator in keeping them in school since many students drop out in order to make some money
Galileo\u27s Revenge: Junk Science in the Courtroom
A Review of Galileo\u27s Revenge: Junk Science in the Courtroom by Peter W. Hube
Balancing Commerce, History, and Geography: Defining the Navigable Waters of the United States
This Note develops a simple set of principles useful for defining navigable waters in a contemporary context. Part I considers why federal admiralty jurisdiction exists, and traces the evolution of the phrase navigable waters as a term of art. Part II analyzes the conflicting contemporary definitions of navigable waters. Part III resolves the conflict by proposing guidelines that address the major concerns of all competing definitions. The system advocated is consistent with the goals of admiralty, constitutionally sound, easy to apply, and focuses attention on the nexus test to resolve the issue of whether particular cases belong in admiralty
Nowcasting ETAS Earthquakes: Information Entropy of Earthquake Catalogs
Earthquake nowcasting has been proposed as a means of tracking the change in
large earthquake potential in a seismically active area. The method was
developed using observable seismic data, in which probabilities of future large
earthquakes can be computed using Receiver Operating Characteristic (ROC)
methods. Furthermore, analysis of the Shannon information content of the
earthquake catalogs has been used to show that there is information contained
in the catalogs, and that it can vary in time. So an important question
remains, where does the information originate? In this paper, we examine this
question using statistical simulations of earthquake catalogs computed using
Epidemic Type Aftershock Sequence (ETAS) simulations. ETAS earthquake
simulations are currently in widespread use for a variety of tasks, in
modeling, analysis and forecasting. After examining several of the standard
ETAS models, we propose a version of the ETAS model that conforms to the
standard ETAS statistical relations of magnitude-frequency scaling, aftershock
scaling, Bath's law, and the productivity relation, but with an additional
property. We modify the model to introduce variable non-Poisson aftershock
clustering, inasmuch as we test the hypothesis that the information in the
catalogs originates from aftershock clustering. We find that significant
information in the catalogs arises from the non-Poisson aftershock clustering,
implying that the common practice of de-clustering catalogs may remove
information that would otherwise be useful in forecasting and nowcasting. We
also show that the nowcasting method provides similar results with the the ETAS
models as it does with observed seismicity.Comment: 17 pages, 3 figures, 1 tabl
Experimental Investigation of the Effects of Support Interference on the Pressure Distribution of a Body of Revolution at a Mach Number of 3.12 and Reynolds Numbers from 2 x 10(exp 6) to 14 x 10(exp 6)
A compilation of available information on the problem of support interference at transonic and supersonic speeds is presented. (author
Investigation of Cracks Found in Helicopter Longerons
Four cracked longerons, containing a total of eight cracks, were provided for study. Cracked regions were cut from the longerons. Load was applied to open the cracks, enabling crack surface examination. Examination revealed that crack propagation was driven by fatigue loading in all eight cases. Fatigue crack initiation appears to have occurred on the top edge of the longerons near geometric changes that affect component bending stiffness. Additionally, metallurigical analysis has revealed a local depletion in alloying elements in the crack initiation regions that may be a contributing factor. Fatigue crack propagation appeared to be initially driven by opening-mode loading, but at a crack length of approximately 0.5 inches (12.7 mm), there is evidence of mixed-mode crack loading. For the longest cracks studied, shear-mode displacements destroyed crack-surface features of interest over significant portions of the crack surfaces
Investigation of Helicopter Longeron Cracks
Four cracked longerons, containing a total of eight cracks, were provided for study. Cracked regions were cut from the longerons. Load was applied to open the cracks, enabling crack surface examination. Examination revealed that crack propagation was driven by fatigue loading in all eight cases. Fatigue crack initiation appears to have occurred on the top edge of the longerons near geometric changes that affect component bending stiffness. Additionally, metallurgical analysis has revealed a local depletion in alloying elements in the crack initiation regions that may be a contributing factor. Fatigue crack propagation appeared to be initially driven by opening-mode loading, but at a crack length of approximately 0.5 inches (12.7 mm), there is evidence of mixed-mode crack loading. For the longest cracks studied, shear-mode displacements destroyed crack-surface features of interest over significant portions of the crack surfaces
Failure Analysis of Electrical Pin Connectors
A study was initiated to determine the root cause of failure for circuit board electrical connection pins that failed during vibRatory testing. The circuit board is part of an unmanned space probe, and the vibratory testing was performed to ensure component survival of launch loading conditions. The results of this study show that the pins failed as a result of fatigue loading
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