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11.
At present, WLANs supporting broadband multimedia communications are being developed and deployed around the world. Standards include HIPERLAN/2 defined by ETSI BRAN and the 802.11 family defined by the IEEE. These systems provide channel adaptive data rates up to 54 Mb/s (in a 20 MHz channel spacing) over short ranges up to 200 m. The HIPERLAN/2 standard also specifies a flexible radio access network that can be used with a variety of core networks, including UMTS. It is likely that WLANs will become an important complementary technology to 3G cellular systems and will typically be used to provide hotspot coverage. In this article the complementary use of WLANs in conjunction with UMTS is presented. In order to quantify the capacity enhancement and benefits of cellular/hotspot interworking we have combined novel ray tracing, software-simulated physical layer performance results, and optimal base station deployment analysis. The study focuses on an example deployment using key lamppost mounted WLAN access points to increase the performance (in terms of capacity) of a cellular network. 相似文献
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Molina R. Mateos J. Katsaggelos A.K. Vega M. 《IEEE transactions on image processing》2003,12(12):1642-1654
We develop a multichannel image restoration algorithm using compound Gauss-Markov random fields (CGMRF) models. The line process in the CGMRF allows the channels to share important information regarding the objects present in the scene. In order to estimate the underlying multichannel image, two new iterative algorithms are presented and their convergence is established. They can be considered as extensions of the classical simulated annealing and iterative conditional methods. Experimental results with color images demonstrate the effectiveness of the proposed approaches. 相似文献
13.
Surveys the field of super resolution (SR) processing for compressed video. The introduction of motion vectors, compression noise, and additional redundancies within the image sequence makes this problem fertile ground for novel processing methods. In conducting this survey, though, we develop and present all techniques within the Bayesian framework. This adds consistency to the presentation and facilitates comparison between the different methods. The article is organized as follows. We define the acquisition system utilized by the surveyed procedures. Then we formulate the HR problem within the Bayesian framework and survey models for the acquisition and compression systems. This requires consideration of both the motion vectors and transform coefficients within the compressed bit stream. We survey models for the original HR image intensities and displacement values. We discuss solutions for the SR problem and provide examples of several approaches. 相似文献
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A combined diagnosis of maturity is described, which is harmless in a correct technique. The method can be carried out in each of obstetrical hospital together with a routine laboratory. By means of the combined diagnosis a "maturity-index" is performed, which permits a certain assessment of the survival-chance of the praemature delivered children. In connection with the ultrasound-cephalometrie also there is an exact evidence to the duration of pregnancy and the tendence of intrauterine growth of the fetus. 相似文献
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Influence of denervation on phospholipid metabolism in the vas deferens and effect of phospholipase C treatment on sensitivity of the vas deferens for noradrenaline were studied. The incorporation of 32P-orthophosphate into phosphatidylethanolamine and phosphatidylcholine was markedly increased by denervation. Incorporation of 32P-orthophosphate into proteolipid was accelerated more than that of 3H-leucine. Sensitivity of the denervated vas deferens for noradrenaline was strongly reduced by phospholipase C treatment. These data suggest that the supersensitivity of the denervated vas deferens for noradrenaline was mainly due to the increase in phospholipids. 相似文献
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Metallothionein (MTN), a low molecular weight cytoplasmic metalloprotein has previously been implicated in the metabolism of Zn. Experiments were conducted with rats to determine the effect of feeding varying levels of dietary Zn for short periods on the increase or decrease in MTN-bound Zn. The results indicated that MTN-Zn in both liver and intestinal mucosal cytosol responded rapidly to an altered dietary Zn level and that serum Zn was directly related to the appearance of MTN. 65Zn absorption also responded rapidly to a change in dietary Zn and was inversely correlated with intestinal mucosal MTN-Zn. Hepatic 65Zn uptake appeared to be directly correlated with liver MTN-Zn. A 24 hour fast increased MTN-Zn in rats fed two different levels of Zn except in those rats that were previously treated with actinomycin D. The antibiotic, which blocks DNA-dependent RNA synthesis, appeared to block Zn uptake from blood to the liver. These findings offer support for the involvement of MTN in zinc metabolism. 相似文献
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This paper reports a method for organochlorine pesticide determination in selected fruit species where pesticide residues were extracted and cleaned using a buffered QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method, followed by GC–MS analysis. The method results showed the matrix-matched calibration curve linearity was >0.99 for all target analytes. With pesticide recovery rates (spiked at 0.008 mg kg−1) ranging from 70% to 120%, and RSD values <17% for most compounds, the limit of quantification ranged from 0.001–0.013 mg kg−1. Finally, the method ruggedness was further demonstrated by analysis of actual commercial fruits and baby food samples. 相似文献