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排序方式: 共有1600条查询结果,搜索用时 24 毫秒
61.
Fernandes A.L. Raginsky M. Coleman T.P. 《Signal Processing, IEEE Transactions on》2009,57(5):1731-1744
We propose a scheme for rate-constrained distributed nonparametric regression using a wireless sensor network. The scheme is universal across a wide range of sensor noise models, including unbounded and nonadditive noise; it has low complexity, requiring simple operations such as uniform scalar quantization with dither and message passing between neighboring nodes in the network, and attains minimax optimality for regression functions in common smoothness classes. We present theoretical results on the tradeoff between the compression rate, communication complexity of encoding, and the MSE and demonstrate empirical performance of the scheme using simulations. 相似文献
62.
We investigated, using questionnaires, different strategies for removing drivers’ overoptimism (Svenson et al., 2012a) about how fast their speed could be decreased when they were speeding compared with braking at the speed limit speed. Three different learning groups and a control group made collision speed judgments. The first learning group had the distance a car travels during a driver's reaction time for each problem. The second group had this information and also feedback after each judgment (correct speed). The third group judged collision speed but also braking distance and received correct facts after each problem. The control group had no information at all about reaction time and the distance traveled during that time. The results suggested the following rank order from poor to improved performance: control, group 1, group 3 and group 2 indicating that information about distance driven during a driver's reaction time improved collision speed judgments and that adding stopping distance information did not add to this improvement. 相似文献
63.
Preferences for ancient and modern art museums: Visitor experiences and personality characteristics.
Mastandrea Stefano; Bartoli Gabriella; Bove Giuseppe 《Canadian Metallurgical Quarterly》2009,3(3):164
This research has two main purposes. The first is to replicate and possibly to extend the results obtained in a previous study, where the authors found that visitors to the ancient art museum conducted their visit with the primary aim of acquiring understanding and knowledge, while modern art museum visitors conducted their visit with an approach that was primarily emotional and pleasure-seeking. The second purpose relates to studies showing that people who prefer abstract art present higher levels on personality traits like “Openness to Experience” and “Sensation Seeking,” compared to people who prefer realistic art. This study investigates these two personality traits for people who favor visiting museums of ancient rather than modern art. Results confirmed previous findings that emotional aspects related to the visit were relevant for modern art museum visitors, while a more cognitive approach based on learning characterized ancient art museum visitors. Concerning personality traits, no difference was found between the two museum groups on the “Openness to Experience” dimension; differences were found on the “Sensation Seeking” trait; modern art museum visitors attained higher scores as compared to ancient art museum visitors. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
64.
Scouring at Bed Sills as a Response to Flash Floods 总被引:1,自引:0,他引:1
Matteo Tregnaghi Andrea Marion Stephen Coleman 《Canadian Metallurgical Quarterly》2009,135(6):466-475
The temporal development of clear-water local scour depth at bed sills in uniform gravel beds is considered. Experiments are presented on the development of scour holes under unsteady hydraulic conditions, with the triangular-shaped hydrographs tested being of different durations and different rates of flow variation. Based on the experimental results and a theoretical framework, a method is given for the definition and prediction of the scouring process under unsteady flows in terms of a dimensionless temporal parameter. A “flash flood” is here defined as an event for which the scour doesn’t attain its potential magnitude, i.e., the equilibrium value for the peak hydrograph flow rate. This flood nature is dependent on both the characteristics of the flood event itself and the characteristics of the stream. A quantitative measure of what constitutes a flash flood is given in terms of the identified temporal parameter. Results show that the ratio between the final scour depth and the potential scour depth at a bed sill for a given hydrograph can be estimated as a function of the identified temporal parameter. 相似文献
65.
Univ.-Prof. DI Dr. Helmut Habersack DI Marlene Haimann Ass. Prof. Dr. Sándor Baranya Prof. Dr. János Józsa Mag. Angelika Riegler Dr Christine Sindelar DI Marcel Liedermann Johanna Ficsor Gabriella Mohácsiné Simon HR DI Dr. Michael Hengl 《?sterreichische Wasser- und Abfallwirtschaft》2014,66(9-10):340-347
The multiple uses of the Danube River for navigation, hydropower production and as a drinking water supply influence its ecological quality. Flow restrictions due to regulation as well as impacts on the sediment regime such as retention in the catchment area and interruption of the sediment continuum result in changes of the hydromorphological structures and can produce major problems in the context of sediment management. In light of these facts, cross-border investigations of sediment transport at the Danube River are called for. As there are no uniform research approaches shared by Austria and Hungary, the EU-funded project SEDDON (Sediment Research and Management at the Danube River) aims to compare different monitoring and modeling techniques used to determine sediment transport, and to develop mutual solutions. Further, the laboratory equipment currently used for hydraulic model experiments is evaluated and a research channel with a free flowing discharge of up to 10 m3/s without pumping will be constructed, allowing large-scale joint laboratory tests concerning sediment to be performed. 相似文献
66.
In a grain-boundary-engineered (GBE) microstructure, Σ9 boundaries are the second most abundant boundary type. This article
presents data showing that, in GBE copper, most Σ9s were special. Σ9 boundaries are also a geometrically necessary component
of a GBE microstructure. It is suggested that there are competing requirements for Σ9s; during iterative GBE processing, they
are required to be mobile, whereas afterward, it is desirable that they are special boundaries. 相似文献
67.
Gloria Bordogna Gabriella Pasi 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2010,14(8):799-809
In this paper, a flexible multi criteria information filtering model is presented. This model is flexible since it allows
choosing several distinct criteria, such as content
aboutness, coverage, novelty, trust, timeliness, and combining them by a soft aggregation to define a personalized filter. The personal filter is encoded into the user profile
that also contains the representations of the user interests that can evolve over time. An implementation of the system applying
a combination of the aboutness and coverage criteria has been evaluated and compared to other filtering systems, showing its superior effectiveness. Finally, the possible
use of the other criterion is discussed. 相似文献
68.
Sara Morandi Claudia Focardi Mila Nocentini Marta Puggelli Gabriella Caminati 《Food Analytical Methods》2009,2(4):271-281
The development of a fast and reliable screening method for the determination of tetracycline residues in milk is described
and compared to high-performance liquid chromatography. The method is based on europium-sensitized luminescence: The emissive
properties of the lanthanide cation are used as a fingerprint of europium (III) complexation with tetracycline. The optimization
of the extraction and purification procedures provided a simple and convenient route to prepare stable tetracycline samples
that can safely resist freezing cycles. The method is validated for the first time in milk matrix: The results show that accuracy
and precision of the method meet complaints with the criteria of the Commission Decision 2002/657/EC. The proposed method
has a false compliant rate (β error) lower than 5%. 相似文献
69.
Marisa Di Sabatino Mari Juel Lars Arnberg Martin Syvertsen Gabriella Tranell 《Transactions of the Indian Institute of Metals》2009,62(4-5):511-513
Two different cooling rates have been imposed during the early solidification of two multi-crystalline silicon ingots with 250mm diameter and 100mm height in a pilot scale directional solidification furnace. This has been done by opening a variable heat leak system below the crucible in order to achieve a high initial cooling rate in one of the ingots. The grain-structure and -orientation of these two ingots have been investigated by light microscopy (LM) and electron backscattered diffraction (EBSD), and their electrical properties by quasi-steady state photo-conductance (QSSPC) and surface photovoltage (SPV) method. The ingot with the high initial cooling rate shows predominantly grains which are significantly larger than what is usually found in mc-Si. The minority carrier diffusion lengths measured on the large grains in the ingot with high cooling rate show higher values than those measured on the ingot with smaller grains. These results indicate that principles of grain size and -orientation control in mc-Si ingots can be applied to a pilot scale furnace, and the potential for up-scaling to industrial ingots with improved electrical properties and, thus, higher solar cell conversion efficiency. 相似文献
70.
Mauro Epifani Marco Alvisi Luciana Mirenghi Gabriella Leo Pietro Siciliano Lorenzo Vasanelli 《Journal of the American Ceramic Society》2001,84(1):48-54
A chloride-based inorganic sol–gel route was used for preparing pure and metal (osmium, nickel, palladium, platinum)-doped SnO2 sol. SnCl4 was first reacted with propanol, then the resulting compound was hydrolyzed and subsequently mixed with solutions of the metal dopants. The obtained sols were used for depositing thin films by spin coating or for preparing powders by solvent evaporation at 110°C. FTIR spectroscopy and thermal analysis of the powders revealed that chlorine still bound to tin stabilized the sol against gelation by hindering the condensation reactions. Film characterizations showed that platinum and palladium, unlike nickel and osmium, were likely to form nanoparticles in the SnO2 lattice. This result was discussed with regard to the different ways that platinum and palladium, on one hand, and nickel and osmium, on the other, modified the growth of SnO2 grains and the film roughness and morphology. Dopants that formed nanoparticles (platinum, palladium) resulted in the roughest film, while dopants that did not form particles (nickel, osmium) resulted in SnO2 grain size very close to that of pure SnO2 . 相似文献