18,692 research outputs found
Not All Explanations Predict Satisfactorily, and Not All Good Predictions Explain
This short comment on Epstein's (2008) paper and on the response by Thompson and Derr argues that the symmetry between explanation and prediction cannot satisfactorily be discussed without making clear what prediction means - depending on which connotations the authors have with 'prediction' their arguments can or cannot be accepted.[No keywords]
Reply to the Comment of den Hartog and van Wees on "Conductance Fluctuations in Mesoscopic Normal-Metal/Superconductor Samples"
In their comment cond-mat/9710285 [Phys. Rev. Lett. 80, 5024 (1998)] den
Hartog and van Wees (HW) raise objections against our analysis of the
experimental data presented in cond-mat/9708162 [Phys. Rev. Lett. 79, 1547
(1997)]. According to HW, we did not account for the quantum phase incoherence
introduced by the Niobium compounds of the investigated Nb/Au hybrid samples.
Here we show that and why this criticism is not justified. Some difficulties
associated with a precise determination of the coherence lengths are discussed.
It is discussed why these uncertainties do not have a qualitative impact on the
results reported in our paper.Comment: Reply to the comment cond-mat/9710285 by den Hartog and van Wees; 1
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Three years of experience with the STELLA robotic observatory
Since May 2006, the two STELLA robotic telescopes at the Izana observatory in
Tenerife, Spain, delivered an almost uninterrupted stream of scientific data.
To achieve such a high level of autonomous operation, the replacement of all
troubleshooting skills of a regular observer in software was required. Care
must be taken on error handling issues and on robustness of the algorithms
used. In the current paper, we summarize the approaches we followed in the
STELLA observatory
Vertical Product Differentiation When Quality is Unobservable to Buyers
We analyze vertical product differentiation in a model where a good’s quality is unobservable to buyers before purchase, a continuum of quality levels is technologically feasible, and minimum quality is supplied under competitive conditions. After purchase the true quality of the good is revealed with positive probability. To provide firms with incentives to actually deliver promised quality, prices must exceed marginal cost. We derive sufficient conditions for these incentive constraints to determine equilibrium prices, and show that under certain conditions only one or both of the extreme levels of quality, minimum and maximum quality, are available in the market.experience goods, product differentiation, product quality, asymmetric information
Epistemological Perspectives on Simulation
This special section includes papers originally presented at a workshop on \'Epistemological Perspectives on Simulation\' in July 2004 at the University of Koblenz, in which some thirty colleagues participated. It had been our impression that there was (and still is) a small, but growing number of researchers who are interested in investigating the preconditions of successfully deploying simulation as a research tool. We were convinced that discussing the epistemological status of simulation in a cross-disciplinary setting could contribute to a deeper understanding of relevant issues and so it proved.Simulation, Epistemology, Methodology
A relative Hilbert-Mumford criterion
We generalize the classical Hilbert-Mumford criteria for GIT (semi-)stability
in terms of one parameter subgroups of a linearly reductive group G over a
field k, to the relative situation of an equivariant, projective morphism X ->
Spec A to a noetherian k-algebra A. We also extend the classical projectivity
result for GIT quotients: the induced morphism X^ss/G -> Spec A^G is
projective. As an example of applications to moduli problems, we consider
degenerations of Hilbert schemes of points.Comment: v4: minor correction
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