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排序方式: 共有106条查询结果,搜索用时 15 毫秒
1.
Yanhong Li Lopresti D. Nagy G. Tomkins A. 《IEEE transactions on pattern analysis and machine intelligence》1996,18(2):99-107
Considers the problem of evaluating character image generators that model distortions encountered in optical character recognition (OCR). While a number of such defect models have been proposed, the contention that they produce the desired result is typically argued in an ad hoc and informal way. The authors introduce a rigorous and more pragmatic definition of when a model is accurate: they say a defect model is validated if the OCR errors induced by the model are indistinguishable from the errors encountered when using real scanned documents. The authors describe four measures to quantify this similarity, and compare and contrast them using over ten million scanned and synthesized characters in three fonts. The measures differentiate effectively between different fonts and different scans of the same font regardless of the underlying text 相似文献
2.
Shimizu Toru; Bowers Alexia N.; Budzynski Cheri A.; Kahn Meghan C.; Bingman Verner P. 《Canadian Metallurgical Quarterly》2004,118(4):845
Lesion studies have shown that the avian hippocampus plays a crucial role in homing pigeon (Columba livia) navigation. Using the expression of the immediate early gene protein ZENK in intact pigeons, the authors found regional variation in hippocampal activation as a consequence of homing and, necessarily, the behavior and internal states that accompany it. Specifically, pigeons that homed displayed a significant increase in the number of ZENK-labeled cells in the lateral hippocampal formation compared with pigeons that did not home, whereas no difference was seen in the medial hippocampus. Significant changes in ZENK expression were also found in the medial striatum, which resembles the mammalian ventral striatum. The results identify portions of the hippocampal formation and the medial striatum as sites of plasticity associated with homing. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Magnetic Resonance Materials in Physics, Biology and Medicine - To show the relevance of a simple finite difference transmission line model to help design safe implanted cables in 1.5T MRI’s... 相似文献
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The theory of state-variable feedback decoupling in multivariable control systems is generalized to include the case where a subset of the output set is the candidate for decoupling. Systems in which such decoupling is employed will be termed "partially decoupled." Decoupling a selected set of outputs, when achieved by using a state feedback matrixF and a nousingular (m times m ) input matrixG , will be calledm -input decoupling (MID), to reflect the restriction on the input matrix. An algorithm, developed by Silverman for constructing inverse systems, is shown to play an essential role in the MID problem, and using matrices constructed in the algorithm, necessary, and sufficient conditions form -input decoupling the specified set of outputs are obtained. As would be expected, these necessary and sufficient conditions include the existing conditions for decoupling all system outputs as a special case. An example is given illustrating the results. 相似文献
5.
Freeze-Dried Fennel Oleoresin Products Formed by Biopolymers: Storage Stability and Characterization
Charikleia Chranioti Alexia Karamberi Lamprini-Areti Tsakanika Constantina Tzia 《Food and Bioprocess Technology》2016,9(12):2002-2011
In this work, fennel oleoresin (FO) was encapsulated through freeze drying of the so produced emulsions within different edible biopolymeric carriers. Specifically, modified starch, maltodextrin, chitosan, and gum arabic were used as carriers both individually and in blends (binary and ternary ones). The freeze-dried FO products were characterized in terms of structure (X-ray diffraction (XRD) analysis), whereas their stability was studied by means of sorption isotherm analysis under various a w. Moreover, the formation of complexes was evaluated through Fourier transform infrared spectroscopy (FTIR) technique and ζ-potential analysis. The verification of the encapsulation process was also conducted by applying FTIR technique. Results showed that the final products presented an amorphous character, whereas the sorption isotherms could be described adequately by the Guggenheim-Anderson-de Boer (GAB) model. FTIR technique proved to be effective to confirm both the formation of complexes and the presence of FO into the studied carriers, verifying thus the success of the process. 相似文献
6.
Emmanuel Hatzakis Alexia Agiomyrgianaki Photis Dais 《Journal of the American Oil Chemists' Society》2010,87(1):29-34
31P-Nuclear magnetic resonance (NMR) spectroscopy was employed to detect and quantify free glycerol in virgin olive oils originating from various regions of Greece. This analytical method was based on the derivatization of the hydroxyl groups of glycerol with the tagging reagent 2-chloro-4,4,5,5-tetramethyldioxaphospholane, and identification of the phosphitylated compound on the basis of 31P chemical shifts. Quantification of glycerol in olive oils was accomplished by integration of the appropriate signals in the 31P NMR spectrum and the use of the phosphitylated cyclohexanol as internal standard. A linear correlation was observed between the glycerol content and 1,3-diacylglycerols and free acidity indicating that glycerol is the final product of the partial hydrolysis of triacylglycerols. 相似文献
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Robert Lopresti 《Scientometrics》2010,85(3):647-655
Citations in five leading environmental science journals were examined for accuracy. 24.41% of the 2,650 citations checked were found to contain errors. The largest category of errors was in the author field. Of the five journals Conservation Biology had the lowest percentage of citations with errors and Climatic Change had the highest. Of the citations with errors that could be checked in Web of Science, 18.18% of the errors caused a search for the cited article to fail. Citations containing electronic links had fewer errors than those without. 相似文献
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This article suggests a novel method to retrieve a narrowband signal sent in a multipath environment with a delay spread considering ISI between symbols. The proposed method does not require any preamble nor known signal. Using the joint direction and time delay of arrivals estimation algorithm developed in prior work, the directions and time delays of arrival in the multipath channel are jointly estimated and associated while keeping a low computational cost. In this process, a MVDR beamformed copy of each arriving signal is created. The quality of these “pseudo copies” is evaluated and compared to the original direct and reflected signals in this work. Another beamforming method, the Moore–Penrose pseudoinverse, with better retrieval of the direct and reflected signals is also proposed. Using a simple delay-and-sum operation on the previously beamformed copies, it is possible to substantially improve the the system’s performance in terms of bit error rate. An approach using oversampling on the array antenna is introduced to improve performance. Numerical simulations are discussed to support theory. 相似文献