1,241 research outputs found

    Decision tree rating scales for workload estimation: Theme and variations

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    The Modified Cooper-Harper (MCH) scale which is a sensitive indicator of workload in several different types of aircrew tasks was examined. The study determined if variations of the scale might provide greater sensitivity and the reasons for the sensitivity of the scale. The MCH scale and five newly devised scales were examined in two different aircraft simulator experiments in which pilot loading was treated as an independent variable. It is indicated that while one of the new scales may be more sensitive in a given experiment, task dependency is a problem. The MCH scale exhibits consistent senstivity and remains the scale recommended for general use. The MCH scale results are consistent with earlier experiments. The rating scale experiments are reported and the questionnaire results which were directed to obtain a better understanding of the reasons for the relative sensitivity of the MCH scale and its variations are described

    Manipulating Underdetermination in Scientific Controversy: The Case of the Molecular Clock

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    Where there are cases of underdetermination in scientific controversies, such as the case of the molecular clock, scientists may direct the course and terms of dispute by playing off the multidimensional framework of theory evaluation. This is because assessment strategies themselves are underdetermined. Within the framework of assessment, there are a variety of trade-offs between different strategies as well as shifting emphases as specific strategies are given more or less weight in assessment situations. When a strategy is underdetermined, scientists can change the dynamics of a controversy by making assessments using different combinations of evaluation strategies and/or weighting whatever strategies are in play in different ways. Following an underdetermination strategy does not end or resolve a scientific dispute. Consequently, manipulating underdetermination is a feature of controversy dynamics and not controversy closure

    Sewall Wright\u27s Adaptive Landscape: Philosophical Reflections on Heuristic Value

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    This volume brings together prominent historians of science, philosophers, ecologists, and evolutionary biologists, with the aim of discussing the state of the art of the Adaptive Landscape from several different perspectives

    A Shifting Terrain: A Brief History of the Adaptive Landscape

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    This volume brings together prominent historians of science, philosophers, ecologists, and evolutionary biologists, with the aim of discussing the state of the art of the Adaptive Landscape from several different perspectives

    Particle characterisation of rail sands for understanding tribological behaviour

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    Low adhesion between a train’s wheel and the rail can cause performance and safety issues, costing the UK rail industry ~£345 m/annum. Sand is applied to the wheel/rail interface to increase traction when low adhesion conditions are present. In order to improve performance, an understanding of how particles are entrained into and act within the interface is needed. This paper outlines a particle characterisation framework and applies it to sands used in the rail industry: Leighton Buzzard (LB), Central European (CE), and Derbyshire Youlgreave (DY) sand. The largest difference found in this framework was between the sand’s particle size, LB being largest, then CE, then DY. A high pressure torsion rig measured traction when the sands were applied to dry, wet, and leaf extract contaminated conditions, the latter two representing low adhesion conditions. All sands had no impact on wheel/rail adhesion in dry conditions; in low adhesion conditions DY had little influence, whereas LB and CE were found to increase traction. Particles in dry conditions had no effect on test specimen surface roughness, whereas roughness increased when sand was applied in low adhesion conditions. The developed characterisation framework provides a platform for assessing prospective adhesion enhancing particles

    Finding core-periphery structures with node influences

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    Detecting core-periphery structures is one of the outstanding issues in complex network analysis. Various algorithms can identify core nodes and periphery nodes. Recent advances found that many networks from real-world data can be better modeled with multiple pairs of core-periphery nodes. In this study, we propose to use an influence propagation process to detect multiple pairs of core-periphery nodes. In this framework, we assume each node can emit a certain amount of influence and propagate it through the network. Then we identify nodes with large influences as core nodes, and we utilize a maximum influence chain to construct a node-pairing network to determine core-periphery pairs. This approach can take node interactions into consideration and can reduce noises in finding pairs. Experiments on randomly generated networks and real-world networks confirm the efficiency and accuracy of our algorithm

    Patterns of accelerometer-assessed physical activity patterns in adolescents.

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    Presented at: 8th Biennial Childhood Obesity Conference; June 29-July 2, 2015; San Diego, CA.https://digitalrepository.unm.edu/prc-posters-presentations/1042/thumbnail.jp

    Physical activity patterns of adolescents by wrist-worn Geneactiv accelerometer.

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    Presented at: American College of Sports Medicine Annual Meeting; May 26-30, 2015; San Diego, CA.https://digitalrepository.unm.edu/prc-posters-presentations/1046/thumbnail.jp

    Dihydrogen: Vs. hydrogen bonding in the solvation of ammonia borane by tetrahydrofuran and liquid ammonia

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    The solvation structures of two systems rich in hydrogen and dihydrogen bonding interactions have been studied in detail experimentally through neutron diffraction with hydrogen/deuterium isotopic substitution. The results were analysed by an atomistic Monte Carlo simulation employing refinement to the experimental scattering data. The systems studied were the hydrogen storage material ammonia borane (NH 3 BH 3 , AB) dissolved in tetrahydrofuran (THF), and liquid ammonia (NH 3 ), the latter in which AB shows unusually high solubility (260 g AB per 100 g NH 3 ) and potential regeneration properties. The full orientational and positional manner in which AB-AB, AB-THF and AB-NH 3 pairs interact with each other were successfully deciphered from the wide Q-range total neutro n scattering data. This provided an unprecedented level of detail into such highly (di)hydrogen bonding solute-solvent interactions. In particular this allowed insight into the way in which H-B acts as a hydrogen bond acceptor. The (di)hydrogen bonding was naturally determined to dictate the intermolecular interactions, at times negating the otherwise expected tendency for polar molecules to align themselves with anti-parallel dipole moments. Several causes for the extreme solubility of AB in ammonia were determined, including the ability of ammonia to (di)hydrogen bond to both ends of the AB molecule and the small size of the ammonia molecule relative to AB and THF. The AB B-H to ammonia H dihydrogen bond was found to dominate the intermolecular interactions, occurring almost three times more often than any other hydrogen or dihydrogen bond in the system. The favourability of this interaction was seen on the bulk scale by a large decrease in AB clustering in ammonia compared to in the dihydrogen bond-less THF
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