2,481 research outputs found
Bayesian and maximin optimal designs for heteroscedastic regression models
The problem of constructing standardized maximin D-optimal designs for weighted polynomial regression models is addressed. In particular it is shown that, by following the broad approach to the construction of maximin designs introduced recently by Dette, Haines and Imhof (2003), such designs can be obtained as weak limits of the corresponding Bayesian Φq-optimal designs. The approach is illustrated for two specific weighted polynomial models and also for a particular growth model. --
Strongly birefringent cut-wire pair structure as negative index wave plates at THz frequencies
We report a new approach for the design and fabrication of thin wave plates
with high transmission in the terahertz (THz) regime. The wave plates are based
on strongly birefringent cut-wire pair metamaterials that exhibit refractive
indices of opposite signs for two orthogonal polarization components of an
incident wave. As specific examples, we fabricated and investigated a quarter-
and a half-wave plate that revealed a peak intensity transmittance of 74% and
58% at 1.34 THz and 1.3 THz, respectively. Furthermore, the half wave plate
displayed a maximum figure of merit (FOM) of 23 at 1.3 THz where the refractive
index was -1.7. This corresponds to one of the highest FOMs reported at THz
frequencies so far. The presented results evidence that negative index
materials enter an application stage in terms of optical components for the THz
technology.Comment: 4 pages, 3 figures, submitted to Appl. Phys. Let
Maximin and Bayesian optimal designs for regression models
For many problems of statistical inference in regression modelling, the Fisher information matrix depends on certain nuisance parameters which are unknown and which enter the model nonlinearly. A common strategy to deal with this problem within the context of design is to construct maximin optimal designs as those designs which maximize the minimum value of a real valued (standardized) function of the Fisher information matrix, where the minimum is taken over a specified range of the unknown parameters. The maximin criterion is not differentiable and the construction of the associated optimal designs is therefore difficult to achieve in practice. In the present paper the relationship between maximin optimal designs and a class of Bayesian optimal designs for which the associated criteria are differentiable is explored. In particular, a general methodology for determining maximin optimal designs is introduced based on the fact that in many cases these designs can be obtained as weak limits of appropriate Bayesian optimal designs. --maximin optimal designs,Bayesian optimal designs,nonlinear regression models,parameter estimation,least favourable prior
Radiation Hardness and Linearity Studies of CVD Diamonds
We report on the behavior of CVD diamonds under intense electromagnetic
radiation and on the response of the detector to high density of deposited
energy. Diamonds have been found to remain unaffected after doses of 10 MGy of
MeV-range photons and the diamond response to energy depositions of up to 250
GeV/cm^3 has been found to be linear to better than 2 %. These observations
make diamond an attractive detector material for a calorimeter in the very
forward region of the detector proposed for TESLA.Comment: 4 pages, 5 figures; Proceeding for the topical Seminar on Innovative
Particle and Radiation Detectors Siena, 21-24 October 2002; to appear in
Nucl.Phys. B (Proceedings Supplement
Informed Systems at Pacific University Libraries: Information Exchange for Knowledge Creation
University of the Pacific Libraries initiated a workplace systems design initiative in 2016. The participatory action research project engaged co-workers in data collection, analysis, interpretation, and reflection. Results furthered understanding about using information to learn in job-related information use stories. These insights guided co-design of systems for information exchange and conditions for workplace learning. Now, information centered, technology enabled, and human mediated communication systems and professional practices support co-worker engagement in re-invention of library facilities, services, and resources.
Local results are presented within the theoretical framework of Informed Systems, in development for over a decade by a distributed international research team who aim to foster information exchange for knowledge creation through working together in contemporary organizations. Concluding reflections explore value added synergies created through information-centered, action-oriented, technology-enabled, and learning-focused systems design, which builds organizational capacity as colleagues use information to learn in ever expanding professional contexts
Detailed analysis of radiation data from the Gemini 4 and Gemini 7 proton-electron spectrometer experiments Final report, 13 Jun. 1967 - 30 Dec. 1968
Detailed analysis of radiation data from Gemini 4 and 7 proton-electron spectrometer experiment
The ARGUS Vertex Trigger
A fast second level trigger has been developed for the ARGUS experiment which
recognizes tracks originating from the interaction region. The processor
compares the hits in the ARGUS Micro Vertex Drift Chamber to 245760 masks
stored in random access memories. The masks which are fully defined in three
dimensions are able to reject tracks originating in the wall of the narrow
beampipe of 10.5\,mm radius.Comment: gzipped Postscript, 27 page
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