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61.
We propose a novel form of nonlinear stochastic filtering based on an iterative evaluation of a Kalman-like gain matrix computed within a Monte Carlo scheme as suggested by the form of the parent equation of nonlinear filtering (Kushner–Stratonovich equation) and retains the simplicity of implementation of an ensemble Kalman filter (EnKF). The numerical results, presently obtained via EnKF-like simulations with or without a reduced-rank unscented transformation, clearly indicate remarkably superior filter convergence and accuracy vis-à-vis most available filtering schemes and eminent applicability of the methods to higher dimensional dynamic system identification problems of engineering interest. 相似文献
62.
Dale Whittington 《Educational Measurement》1999,18(1):14-22
Can validity and reliability be taught from the perspective of the decisions classroom teachers make instead of from a more purely psychometric perspective? What aspects of validity and reliability are particularly relevant for classroom teachers? 相似文献
63.
This is a list of books that should be available in either the hospital emergency room or the medical library. The forty-nine books listed are divided into the following categories: General, Surgery and Trauma, Burns, Cardiology, Dentistry, Disaster Medicine, First Aid, Geriatrics, Obstetrics, Pediatrics, Psychiatry, Toxicology, and Transportation. An asterisk has been placed before twelve books that are particularly recommended for the hospital emergency room as well as the medical library. The latest edition is given for each book, and, unless otherwise noted, each has been annotated by one of the authors. 相似文献
65.
Analysis of academic administrators’ attitudes: annual evaluations and factors that improve teaching
Brian D. Cherry Nathan Grasse Dale Kapla Brad Hamel 《Journal of Higher Education Policy & Management》2017,39(3):296-306
This article examines academic administrators’ attitudes towards the academic evaluation process in the US and those factors that are utilised to improve teaching. We use path regressions to examine satisfaction with evaluation procedures, as well as the direct and indirect effects of these factors on perceptions of whether the evaluation process facilitates quality instruction. With increased pressure for accountability being placed on higher education, it is important to ensure that we are meeting both public and academic expectations. The evaluation process is an important tool to ensure the university’s goals and values are articulated and that academics can be successful in their individual career paths. The problem is most research finds flaws with the current method of evaluation, and academics and academic administrators are sceptical about the process and results. We find there are environmental factors that influence academic administrators’ perceptions of academic evaluations and the ability to improve classroom instruction. 相似文献
66.
AbstractThis article develops a conceptual model of users’ and designers’ knowledge roles in the information and communication technology design process. The “ideal” center at the intersection of the axes for division of knowledge work and privileging of knowledges represents a balanced distribution of knowledge work between users and designers and an avoidance of privileging either group over the other. The article then applies this model to analyses of the design process for six video games wherein the knowledges of Indigenous peoples in North America were mobilized. It concludes by discussing implications for research and design practice, particularly for broadening the participation and self-articulation of marginalized groups. 相似文献
67.
In 2003, donors combined together in Vietnam to support the provision of quality primary schooling for 226 disadvantaged districts (about a third of the country). US$160 million was invested in infrastructure, materials and training across the 226 districts. The programme has been commended by donors and received good press inside Vietnam. Comparison of achievement surveys in 2001 and 2007 showed, however, that there had been a decline in performance in the targeted districts. This article explores various hypotheses as to how this could have happened; and in particular the increasing amounts spent by better-off households on their children's education. 相似文献
68.
Motivated by the wide application of Markov-chain steady-state-probability estimation, we pursue a spectral and graph-theoretic performance analysis of a classical estimator for steady-state probabilities here. Specifically, we connect a performance measure to estimate the structure of the underlying graph defined on the Markov-chain's state transitions. To do so, (1) we present a series of upper bounds on the performance measure in terms of the subdominant eigenvalue of the state transition matrix, which is closely connected with the graph structure; (2) as an illustration of the graph-theoretic analysis, we then relate the subdominant eigenvalue to the connectivity of the graph, including for the strong-connectivity case and the weak-link case. We also apply the results to characterize estimation in Markov chains with rewards. 相似文献
69.
In this paper, we present a movement-based assay to observe adaptability in Caenorhabditis elegans locomotion behavior. The assay comprises a series of sinusoidal microchannels with a fixed wavelength and modulating (increasing or decreasing) amplitude. The channel width is comparable to the body diameter of the organism. Worms are allowed to enter the channel from the input port and migrate toward the output port. Within channel sections that closely match the worm's natural undulations, the worm movement is relatively quick and steady. As the channel amplitude increases or decreases along the device, the worm faces difficulty in generating the propulsive thrust, begins to slow down and eventually fails to move forward. A set of locomotion parameters (i.e., average forward velocity, number and duration of stops, range of contact angle, and cut-off region) is defined for worm locomotion in modulated sinusoidal channels and extracted from the recorded videos. The device is tested on wild-type C. elegans (N2) and two mutants (lev-8 and unc-38). We anticipate this passive, movement-based assay can be used to screen nematodes showing difference in locomotion phenotype. 相似文献
70.
Elizabeth Cay (1771–1831), the grandmother of the Scottish physicist James Clerk Maxwell (1831–1879), was a talented amateur pastellist; several of her pastel portraits survive as does her set of pastels. She studied with Archibald Skirving (1749–1819), a Scottish miniature painter who later in life turned to larger-scale portraiture in pastel and served as drawing master to the Edinburgh elite. Cay's pastels are not fabricated sticks but consist of powdered pigment housed in various glass and ceramic containers and were apparently applied by stumps, still in her workbox, or brushes. The Cay color samples were identified by spectrographic analysis, polarized light microscopy, and microchemical tests which, in addition, indicated that a number of pigment mixtures present gave specific hues in keeping with earlier treatise accounts of the preparation of a pastel gamut for practical use. Elizabeth Cay's pastel workbox may be rare surviving evidence of one way, more common that we appreciate today, in which amateurs, and perhaps professionals, practiced pastel painting. 相似文献