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11.
Detail preserving impulsive noise removal 总被引:8,自引:0,他引:8
Most image processing applications require noise elimination. For example, in applications where derivative operators are applied, any noise in the image can result in serious errors. Impulsive noise appears as a sprinkle of dark and bright spots. Transmission errors, corrupted pixel elements in the camera sensors, or faulty memory locations can cause impulsive noise. Linear filters fail to suppress impulsive noise. Thus, non-linear filters have been proposed. Windyga's peak-and-valley filter, introduced to remove impulsive noise, identifies noisy pixels and then replaces their values with the minimum or maximum value of their neighbors depending on the noise (dark or bright). Its main disadvantage is that it removes fine image details. In this work, a variation of the peak-and-valley filter is proposed to overcome this problem. It is based on a recursive minimum–maximum method, which replaces the noisy pixel with a value based on neighborhood information. This method preserves constant and edge areas even under high impulsive noise probability. Finally, a comparison study of the peak-and-valley filter, the median filter, and the proposed filter is carried-out using different types of images. The proposed filter outperforms other filters in the noise reduction and the image details preservation. However, it operates slightly slower than the peak-and-valley filter. 相似文献
12.
Four carbohydrate samples extracted from kraft pulps are used as model substrates for studying the mechanism by which xylanase enhances subsequent bleaching of kraft pulp. Fourier transform infrared spectroscopy confirms that small amounts of aromatic molecules, probably lignin, remain associated with these carbohydrate samples. When the extracts are hydrolyzed with xylanase or acid, size exclusion chromatography shows a decrease in the molecular mass of their UV-absorbing constituents, as well as their carbohydrate constituents as determined by pulsed amperometric detection. The results are consistent with the hypothesis that xylanase prebleaching hydrolyzes the xylan portion of lignin-carbohydrate complexes to leave smaller lignin-containing macromolecules in pulp fiber, thus facilitating the removal of lignin components by bleaching chemicals. 相似文献
13.
Monique van Scherpenzeel Ed E. Moret Dr. Lluis Ballell Dr. Rob M. J. Liskamp Prof. Dr. Ulf J. Nilsson Dr. Hakon Leffler Dr. Roland J. Pieters Dr. 《Chembiochem : a European journal of chemical biology》2009,10(10):1724-1733
Light up galectin: Photoprobes based on thiodigalactoside were prepared for galectin‐3, a lectin linked to cancer. The probes contained either benzophenone or acetophenone moieties as the photolabel for covalent attachment to the protein. One particular probe labeled galectin‐3 selectively, even in the presence of cell lysate.
14.
Hepatic and Adipose Tissue Depot-Specific Changes in Lipid Metabolism in Late-Onset Obese (LOB) Rats
Transgenic Late-onset OBesity (LOB) rats slowly develop a male-specific, autosomal dominant, obesity phenotype with a specific
increase in peri-renal white adipose tissue (WAT) depot and preserved insulin sensitivity (Bains et al. in Endocrinology 145:2666–2679,
2004). To better understand the remarkable phenotype of these rats, the lipid metabolism was investigated in male LOB and non-transgenic
(NT) littermates. Total plasma cholesterol (C) levels were normal but total plasma triacylglycerol (TAG) (2.8-fold) and hepatic
TAG content (25%) was elevated in LOB males. Plasma VLDL-C and VLDL-TAG levels were higher while plasma apoB levels were 60%
lower in LOB males. Increased hepatic TAG secretion explained the increased VLDL levels in LOB males. The hepatic gene expression
of FAS, SCD-1, mitochondrial (mt)GPAT, and DGAT2 was up-regulated in both old obese and young non-obese LOB rats. Lipoprotein
lipase (LPL) activity in heart and epididymal white adipose tissue (WAT) was unchanged, while LPL activity was increased in
peri-renal WAT (30%) and decreased in soleus muscle (40%). Moreover, FAS, SCD-1 and DGAT2 gene expression was increased in
peri-renal, but not in epididymal WAT. Basal lipolysis was reduced or unchanged and β-adrenergic stimulated lipolysis was
reduced in WAT from both old obese and young non-obese LOB rats. To summarize, the obese phenotype of LOB male rats is associated
with increased hepatic TAG production and secretion, a shift in LPL activity from skeletal muscle to WAT, reduced lipolytic
response in WAT depots and a specific increase in expression of genes responsible for fatty acid and TAG synthesis in the
peri-renal depot.
F. Frick and R. Hume contributed equally to this work. 相似文献
15.
16.
Nanofluids comprised of silicon dioxide (SiO2) nanoparticles suspended in a 60:40 (% by weight) ethylene glycol and water (EG/water) mixture were investigated for their heat transfer and fluid dynamic performance. First, the rheological properties of different volume percents of SiO2 nanofluids were investigated at varying temperatures. The effect of particle diameter (20 nm, 50 nm, 100 nm) on the viscosity of the fluid was investigated. Subsequent experiments were performed to investigate the convective heat transfer enhancement of nanofluids in the turbulent regime by using the viscosity values measured. The experimental system was first tested with EG/water mixture to establish agreement with the Dittus-Boelter equation for Nusselt number and with Blasius equation for friction factor. The increase in heat transfer coefficient due to nanofluids for various volume concentrations has been presented. Pressure loss was observed to increase with nanoparticle volume concentration. It was observed that an increase in particle diameter increased the heat transfer coefficient. Typical percentage increases of heat transfer coefficient and pressure loss at fixed Reynolds number are presented. 相似文献
17.
Bibliometric maps have the potential to become useful tools for science policy issues. The complexity of the structures, however,
makes it often very difficult to interpret the results. In this study, we present a case study in which we use the bibliometric
mapping results to address a high level science policy issue of research efficiency. By revealing the results in an alternative
way, we increased the utility of bibliometric mapping within the science policy context. Moreover, by including additional
information to the entities in the landscape, we provide useful input for the research potential. 相似文献
18.
Gump Brooks B.; Reihman Jacki; Stewart Paul; Lonky Ed; Granger Douglas A.; Matthews Karen A. 《Canadian Metallurgical Quarterly》2009,28(5):614
Objective: The authors recently reported that blood lead (Pb) was a significant mediator for the positive association between socioeconomic status (SES) and peripheral vascular responses to acute stress in children (B. B. Gump et al., 2007). The present study considers the possibility that Pb may also mediate an association between SES and cortisol responses to acute stress. Design: Early childhood Pb exposure was tested as a mediator for cross-sectional associations between SES and cortisol responses. Main Outcome Measures: The primary outcome was cortisol responses to acute stress in 9.5-year-old children (N = 108). Results: Lower family income was associated with significantly greater cortisol levels following an acute stress task. A mediational analysis confirmed that Pb was a significant mediator for this association. Conclusion: These results reaffirm the importance of considering the chemical environment as well as social and psychological environment when evaluating psychophysiological effects of low SES. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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20.
AbstractBig Data Analytics can be a fantastic business opportunity for many organizations. Already organizations are using advanced analytics to streamline production processes, optimize back office activities, market more effectively, and better satisfy customer demand. That said, it goes without saying (as recent headlines can attest) that sometimes enhanced analytics capabilities can introduce risks such as erosion of privacy, overly-intrusive knowledge about customers, etc.Given this dichotomy, making the decision about when, whether, how much, and how to invest in big data analytics initiatives can be a challenge. Invest too soon and you may obviate existing investments or disrupt business activities; invest too late and you may find that competitors gain advantages that make the market landscape asymmetric.This article outlines how and why applying “tried and true” governance principles can help make this decision easier. For those that have formalized governance structures in place, how they might inform the decision an organization makes in this regard – and for those that don’t have a formalized governance program – how they might co-opt some of those principles to help make this decision more approachable. 相似文献