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排序方式: 共有1672条查询结果,搜索用时 18 毫秒
61.
Emad Abd‐Elrady Bernard Mulgrew 《International Journal of Communication Systems》2014,27(11):3266-3279
The main objective in distributed sensor networks is to reach agreement or consensus on values acquired by the sensors. A common methodology to approach this problem is using the iterative and weighted linear combination of those values to which each sensor has access. Different methods to compute appropriate weights have been extensively studied, but the resulting iterative algorithm still requires many iterations to provide a fairly good estimate of the consensus value. In this paper, different accelerating consensus approaches based on adaptive and non‐adaptive filtering techniques are studied and applied on the problem of acoustic source localization using the adaptive projected subgradient method. A comparative simulation study shows that the non‐adaptive polynomial filters based on Newton's interpolating polynomials and semi‐definite programming can provide more accelerated consensus and better estimation accuracy than adaptive filters evaluated using constrained affine projection algorithm or stochastic gradient algorithm provided that the network topology is known beforehand. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
62.
C. Yahaya M. S. Abd Latiff A. B. Mohamed 《International Journal of Communication Systems》2013,26(3):315-336
The exact contribution of this paper is a review of existing state‐of‐the‐art routing strategies for optical burst switched networks developed by researchers to deal with burst contention before it happens. Routing schemes are implemented in space domain, which make them simple and cost effective. Additionally, the paper points out the importance of routing as an effective way to deal with burst contention compared to other solutions. It also underlines the main differences between contention avoidance schemes and contention resolution techniques for optical burst switched networks. We believe that this review will help different optical burst switched researchers involved in the development of route optimization algorithms to control burst contention. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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65.
A. M. M. Abd El-Rahman M. El-Shafie S. A. El-Kholy 《Petroleum Science and Technology》2017,35(14):1473-1480
Asphalt emulsion produced from local asphalt 60/70 (Suez Co.) was modified with different types of polymers such as epoxy resin, latex styrene butadiene styrene (SBS), poly vinyl acetate (PVA), and with a mixture of two or more types of above mentioned polymers to produce a modified asphalt emulsion with high performance. This paper describes the method and technique for preparing asphalt emulsion as well as the tests, and evaluates several aspects concerning the prepared emulsion such as performance of evaporation residues, fuel and acid resistance, rheological properties, and durability. The results obtained revealed that all the modified asphalt emulsions gave better performance as compared with unmodified emulsion. Asphalt emulsion modified with a mixture of epoxy resin, latex SBR, and PVA showed the best road performance in terms of fuel and acid resistance. It was observed that the weight loss for unmodified binder, residue after evaporation of water, after immersion in kerosene for 120 min is 90% of its initial weight, while the binder improved with a mixture of SBS latex, epoxy resin, and PVA showed a weight loss of ?16% and 9% of its initial weight. Also, the admixture gives high acid resistance (weight loss ~ 9%) after immersing in 5% HCl. The dynamic viscosity test showed that asphalt emulsion modified with a mixture of SBS latex, epoxy resin, and PVA has the highest viscosity value which is a promising indication about the validity of its use for pavement in different applications. 相似文献
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67.
A. Hebeish A. A. Ragheb R. Refai M. A. Saad I. Abd El-Thalouth Dokki 《Starch - St?rke》1994,46(3):109-113
The structural changes brought about by introducing different nitrogen containing groups via cyanoethylation, carbamoylethylation and carbamation in the molecules of rice and maize starches and oxidized starches derived thereof and the onset of these changes on the technical properties of yarns sized with such starch products were investigated. It was found that the apparent viscosity of pastes prepared from those products depends on the nature of starch, the degree of oxidation prior to chemical modification, the nature of modification as well as the measuring conditions, i. e. the rate of shear and temperature. Cotton yarns sized using these starch derivatives were measured for yarn number, tensile strength, C.V.%, elongation at break and C.V.% in elongation. Besides, the weavability test expressed as the minimum number of cycles due to abrasion (St1) and average number of cycles due to abrasion (St6) were investigated. A comparison among modified starches prepared from rice starch would reveral that the highest value of St1 is obtained with yarns sized using carbamoylethylated sample derived from unoxidized starch. With maize starch, on the other hand, the highest value of St1 is obtained with cotton yarns sized using carbamoylethylated starch derived from starch oxidized by 1 g/l active chlorine. 相似文献
68.
Guar gum was isolated from the seeds and subjected to modification via non-aqueous carboxymethylation. Highly substituted carboxymethyl guaran derivatives could be obtained via repeating the reaction four times, where a product of degree of substitution (D.S.) 2.07 was obtained indicating that the free hydroxyl groups of both glucose and mannose (which form the main constituents of guaran) can react with monochloro acetic acid. The modification increases the solubility of the gum in cold water, and increases the stability of its pastes to microorganisms. Pastes of these derivatives are characterized by non-Newtonian pseudoplastic behaviour regardless of their D.S. or the measuring temperature, while their apparent viscosity decreases by increasing the D.S. and/or the measuring temperature. 相似文献
69.
Fifteen Baladi and 20 Angora intact males raised together from birth until 8 months of age were grown on a commercial concentrate mixture fed at the rate of 0·6 kg/head/day with chopped wheat straw fed at 0·5 kg/head/day for 14 weeks. Body measurements were taken before slaughter and carcass measurements and offal weights after it. The right sides of all carcasses were dissected into cuts, weighed and deboned. Fat was separated from the 9-10-11 rib joints and estimated. The two breeds did not significantly differ in birth weight, weaning weight, carcass weight, dressing percentage, most body measurements, all carcass measurements and most offal weights. Sigmificant differences were only found in body length, height at withers, weights of spleen and kidney fat. However, the Baladi had significant heavier loin and shoulder (P < 0·05) and breast and flank (P < 0·05) than the Angora which had heavier legs (P < 0·05). The carcasses of the two breeds had very similar percentage of edible meat (68·38 versus 68·65), lean (57·47 versus 57·38) and fat in the rib joint (10·91 versus 11·27). 相似文献
70.
Abdul Latif Ahmad Choe Peng Leo Syamsul Rizal Abd. Shukor 《Journal of Porous Materials》2009,16(1):33-40
Porous γ-alumina with well arranged secondary mesopores has been contrived using nanosized templating units. The pore size
of templated mesopores is precisely controlled as the pore shrinkage is insignificant. The primary pore diameter is ca. 4 nm
and the secondary pore diameter is ca. 50 nm. The porous material was characterized using N2 adsorption/desorption, TEM, XRD and FT-IR. γ-alumina with bimodal pore size distribution shows improved intra-particle diffusion
compared to γ-alumina with unimodal pore size distribution in a simple dye adsorption test. γ-alumina with different porous
structures were then impregnated with vanadium oxide for catalytic effect comparison. It was perceived that secondary pores
improve the styrene oxidation rate after the conversion of styrene reaches 30%. 相似文献