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111.
Stephen A. Stumpf Richard D. Freedman Kenneth M. Krieger 《Research in higher education》1979,11(1):13-22
The Course-Faculty Instrument (CFI) demonstrates similar measurement properties with student populations at four diverse institutions. These students agree about the nature and extent to which course and instructor attributes relate to their learning. The results suggest that: (1) a perceived learning criterion may have general relevance to students, and (2) validity extension research is an economically feasible alternative to full-scale instrument development and validation efforts. Since validity extension is practical and facilitates cross-institutional comparisons, it appears to be a more viable strategy for researching and instituting student evaluation systems than is suggested by its current usage. 相似文献
112.
The primary objective for modeling of machining processes is to develop a predictive capability of machining performance in order to facilitate effective planning of machining operations. This capability leads to faster implementation, higher performance, quality at a lower cost. This comes about due to improved selection of machining parameters, optimal fixture design and the avoidance of tool failure. The simulation system presented simultaneously considers the effect of cutter geometry, the cutter's initial position errors, workpiece geometry, machine tool dynamics, and workpiece/fixture system dynamics on the machining process.The integration of all of the above in one model provides an off-line tool to simulate and optimize the machining parameters and the fixture configuration cutting both lead and production time. The modular nature of the simulation system presented allows for the study of many different machining processes. The cutting forces in this system are modeled using a mechanistic approach. NURBS curves and surfaces are utilized for the geometric modeling and simulation of the machining process. While a finite element method is used to model and analyze the workpiece/fixture dynamics. Two case studies are presented to demonstrate the practical application of the presented simulation. The first case presents the optimization of the fixture configuration of a generic automotive component. While the second case presents the results of simulations performed on a novel mill/grind machining process. This process is a combination of face milling and grinding in one operation. Some simulated results are presented along with experimental validation. 相似文献
113.
Stephen Buck 《期刊图书馆员》2015,68(1-4):106-116
The article will outline the Core Competencies for Electronic Resources Librarians (NASIG Core Competencies Task Force [July 2013]) and intersect them with the practical everyday working experiences of an e-resources and periodicals librarian. The aim of the article is to convey an understanding of working in a practical library office environment, while being aware of the complexity of the theoretical competencies that are desirable and recommended. While it is aimed mainly at librarians, it should also be of interest to publishers and other vendors as they gain an understanding of what it is that librarians (their customers) do all day. 相似文献
114.
Michael J. Kurtz Guenther Eichhorn Alberto Accomazzi Carolyn Grant Markus Demleitner Edwin Henneken Stephen S. Murray 《Information processing & management》2005,41(6):1395-1402
It has been shown (Lawrence, S. (2001). Online or invisible? Nature, 411, 521) that journal articles which have been posted without charge on the internet are more heavily cited than those which have not been. Using data from the NASA Astrophysics Data System (ads.harvard.edu) and from the ArXiv e-print archive at Cornell University (arXiv.org) we examine the causes of this effect. 相似文献
115.
Stephen Marshall 《Distance Education》2014,35(2):250-262
Massive open online courses (MOOCs) represent a potentially exciting opportunity to use technology to realise many of the long-promised benefits of universal higher education. While there are many positive aspects to the MOOCs on offer and in development, there are also significant ethical concerns arising from various initiatives. These include the academic duties of care and integrity, commercial exploitation of learners, as well as research ethics concerns arising from the analytical and other work being done by academics and institutions. These issues are explored and a set of heuristics for individuals and institutions provided as a starting point for ethical analysis of MOOCs and associated activities. 相似文献
116.
Will our teacher certification testing program stand up to a court challenge? What are the critical issues the courts consider in examining teacher certification testing? What do we need to do to strengthen our program legally and psychometrically? 相似文献
117.
Speededness refers to the situation where the time limits on a standardized test do not allow substantial numbers of examinees to fully consider all test items. When tests are not intended to measure speed of responding, speededness introduces a severe threat to the validity of interpretations based on test scores. In this article, we describe test speededness, its potential threats to validity, and traditional and modern methods that can be used to assess the presence of speededness. We argue that more attention must be paid to this issue and that more research must be done to set appropriate time limits on power tests so that speed of responding does not interfere with the construct measured. 相似文献
118.
119.
AbstractA key element contributing to deteriorating exercise capacity during physically demanding sport appears to be reduced carbohydrate availability coupled with an inability to effectively utilize alternative lipid fuel sources. Paradoxically, cognitive and physical decline associated with glycogen depletion occurs in the presence of an over-abundance of fuel stored as body fat that the athlete is apparently unable to access effectively. Current fuelling tactics that emphasize high-carbohydrate intakes before and during exercise inhibit fat utilization. The most efficient approach to accelerate the body’s ability to oxidize fat is to lower dietary carbohydrate intake to a level that results in nutritional ketosis (i.e., circulating ketone levels >0.5 mmol/L) while increasing fat intake for a period of several weeks. The coordinated set of metabolic adaptations that ensures proper interorgan fuel supply in the face of low-carbohydrate availability is referred to as keto-adaptation. Beyond simply providing a stable source of fuel for the brain, the major circulating ketone body, beta-hydroxybutyrate, has recently been shown to act as a signalling molecule capable of altering gene expression, eliciting complementary effects of keto-adaptation that could extend human physical and mental performance beyond current expectation. In this paper, we review these new findings and propose that the shift to fatty acids and ketones as primary fuels when dietary carbohydrate is restricted could be of benefit for some athletes. 相似文献
120.
The tablet computer offers options for streaming TV programming that potentially alters viewing behaviors compared to the traditional television set, yet there is a dearth of research related to this viewing alternative. This study uses a national sample of adult iPad owners to investigate the tablet's role as a TV. The frameworks of continuity-discontinuity, use-diffusion, and attention and absorption to programming are applied to uncover where the tablet fits into the current repertoire of viewing devices, and how individuals are engaging with traditional TV programming through it. Results show that overall, the tablet's functionality as a TV can lead to experiential differences. 相似文献