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101.
Hassan Artail Abdelkarim Ajami Tania Saouma Malak Charaf 《Wireless Communications and Mobile Computing》2016,16(14):1956-1971
This paper presents a faulty node detection approach for wireless sensor networks that aggregate measurement data on their way toward the sink (base station). The approach is based on the idea of commanding sensor nodes on the aggregation paths to temporarily stop including their readings in the received aggregated readings from their upstream neighbors. The scheme is dependent on the ability of the sink to detect faulty nodes through changes in the received aggregated readings at the sink using a Markov Chain Controller (MCC). The algorithm that is run in the sink uses the MCC to assign a state to each sensor node based on transitions that are triggered by receiving aggregated path readings, and accordingly deduces the nodes that may be faulty. The experimental results show at least 98% detection rate at the cost of reasonable detection delays and generated wireless network traffic. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
102.
This paper is concerned with the subjective perception of video coding artifacts in H.264/AVC encoded and decoded video. Our objective is to model the perceived annoyance of such low bit rate video sequences as a function of perceived artifact strength. We introduce a new method for determining this function and apply it to the data from two psychophysical experiments. Both experiments produced numerical judgments of the subjectively perceived annoyance of artifact combinations and the perceived strength of the respective coding artifacts. Our method produces a discrete multi-dimensional representation of the relationships in the data from which the function relating annoyance to artifact strength is derived. The method is applied to the data of the first experiment and the resulting function is shown to describe the data from the second experiment as well. 相似文献
103.
Renewable energy (RE) systems represent the most environmentally friendly and cost-effective means of providing electricity to those living in rural communities or regions in developing countries, however, this has been relatively slow and in many countries the proportion of the rural population supplied with electricity remains low and the proportion supplied with electricity from renewable energy systems is even lower. To understand the causes of this slow progress, a literatures review on renewable rural electrification programs was undertaken. The review suggested a need for better coordination at the national level between those institutions involved in the development and implementation of these programs. This paper compiles and analyse the issues associated with rural electrification in developing countries in Asia and the Pacific. Two case studies of programs are presented, one in Bangladesh and the other in Fiji. Based on the literature review and these two case studies, comments are provided on the policies and strategies required for renewable energy based rural electrification programs. 相似文献
104.
Thomas Erlebach Torben Hagerup Klaus Jansen Moritz Minzlaff Alexander Wolff 《Theory of Computing Systems》2010,47(3):613-636
For t>0 and g≥0, a vertex-weighted graph of total weight W is (t,g)-trimmable if it contains a vertex-induced subgraph of total weight at least (1−1/t)W and with no simple path of more than g edges. A family of graphs is trimmable if for every constant t>0, there is a constant g≥0 such that every vertex-weighted graph in the family is (t,g)-trimmable. We show that every family of graphs of bounded domino treewidth is trimmable. This implies that every family
of graphs of bounded degree is trimmable if the graphs in the family have bounded treewidth or are planar. We also show that
every family of directed graphs of bounded layer bandwidth (a less restrictive condition than bounded directed bandwidth)
is trimmable. As an application of these results, we derive polynomial-time approximation schemes for various forms of the
problem of labeling a subset of given weighted point features with nonoverlapping sliding axes-parallel rectangular labels
so as to maximize the total weight of the labeled features, provided that the ratios of label heights or the ratios of label
lengths are bounded by a constant. This settles one of the last major open questions in the theory of map labeling. 相似文献
105.
Pierre Blaise Veronique Tropini Marie Farines Robert L. Wolff 《Journal of the American Oil Chemists' Society》1997,74(2):165-168
The positional distribution of various Δ5-acids in the seed triacylglycerols from several conifer species has been established
after partial chemical degradation with Grignard reagent. The species studied were representative of four conifer families
and were specially selected for their particularly high Δ5-acid contents. These species were Taxus baccata (Taxaceae; 5,9-18:2 acid, 11.9%), Larix decidua (Pinaceae; 5,9,12-18:3 acid, 28.5%), Sciadopytis verticillata (Taxodiaceae; 5,11,14-20:3 acid, 16.7%), and Juniperus communis (Cupressaceae; 5,11,14,17-20:4 acid, 19.8%). Calculations from the fatty acid compositions of triacylglycerols and of the
mixture of 1,2- and 2,3-diacylglycerols generated by the Grignard reagent indicated that, for the four species, there was
a considerable enrichment of Δ5-acids (generally more than ten times) in the 1,3-positions as compared to the 2-position,
where Δ5-acids represented always less than 2% of total fatty acids esterified to triacylglycerols. This distribution was
practically independent from the species (four families studied), the chainlength (18 or 20 carbon atoms), and the number
of ethylenic bonds (two to four) in the Δ5-acids. Similar distributions were established for triacylglycerols from the seeds
of three pine species that are available on a ton-scale: Pinus pinea, P. koraiensis, and P. pinaster. These observations confirm and extend previous studies conducted with other conifer species by similar techniques or by
13C-nuclear magnetic resonance spectroscopy. Consequently, the almost exclusive location of Δ5-acids in the external positions
of triacylglycerols is now well established and appears to be a general feature of conifer seed oils. 相似文献
106.
A Schmidt CF N?ldechen W Mendling W Hatzmann MH Wolff 《Canadian Metallurgical Quarterly》1997,119(11):545-549
Fungal vaginal infections/colonisations can be divided into a symptomatic vaginal candidiasis and an asymptomatic vaginal Candida-carriage. The latter seems to be a predisposing factor for the development of a symptomatic vaginal candidiasis. The fungal organism isolated most frequently is Candida albicans, followed by Candida glabrata, which was previously also known as Torulopsis glabrata. To a lower extend, other Candida species such as Candida tropicalis and Candida krusei can be prevalent in the vulvovaginal region. Predisposing factors for vaginal candidiasis are gravidity, diabetes mellitus or a therapy with immunosuppressive agents. Also gestagenes showed to be a pre-disposing factor for vaginal candidiasis. Divergent results concerning the predisposition to vaginal candidiasis or colonisation due to oral contraception have so far been reported. Therefore we performed a study with two healthy collectives of female volunteers (n = 2 x 60) which were different concerning the taking of oral contraceptives. Overall, in 17% of the subjects (20/120) yeast could be cultured out of the vaginal secretions. There was no evidence for a higher rate of Candida-colonisation in subjects taking oral contraceptives. Further, there was no evidence for a relationship between the length of the taking of oral contraceptives and the rate of vaginal yeast-carriage. Also the type of oral contraceptive (combination or sequential contraceptive) had no influence on the frequency of Candida-carriage. Candida albicans was the most prevalent yeast (16/20), followed by Candida glabrata (4/20). 相似文献
107.
Berntgen J. Waffenschmidt E. Musolf J. Xiaoyin He Heuken M. Heime K. Hofschen S. Wolff I. 《Microwave Theory and Techniques》1996,44(2):318-325
The microwave properties of coplanar waveguides with line widths from 1 μm to 40 μm made of superconducting YBaCuO films with a thickness t=180 nm on LaAlO3 are investigated. The line impedance ZL and the normalized propagation coefficient β/β0 of these waveguides are measured between 45 MHz and 26.5 GHz at temperatures between 77.4 K and 92 K. The ratio of the line width w to the distance of the ground layers d is constant with w/d=0.2. Therefore, ZL and β/β0 are independent of w for perfectly conducting waveguides. For superconducting waveguides it is found that ZL and β/β0 differ from the values of perfectly conducting waveguides. They increase for smaller line widths at a constant temperature. At w=1 μm and T=80 K, ZL and β/β 0 are nearly twice as high as calculated for perfect conductors. Furthermore, ZL and β/β0 increase with the temperature. It is shown that these effects are attributed to an increase of the inductance per unit length L' due to the superconducting material, whereas the capacitance per unit length C' behaves like C' of perfectly conducting waveguides. Using these results, the dimensions of the superconducting waveguides, which are necessary to obtain a desired ZL at a given line width w, are calculated 相似文献
108.
Olivier Berdeaux Robert L. Wolff 《Journal of the American Oil Chemists' Society》1996,73(10):1323-1326
The fatty acids from the seed oils of three Conifer species (one Pinaceae,Pinus pinaster, and two Cupressaceae,Chamaecyparis lawsoniana andBiota orientalis) have been analyzed as their 4,4-dimethyloxazoline (DMOX) derivatives by gas-liquid chromatography coupled with mass spectrometry.
The structures of six Δ5-unsaturated polymethylene-interrupted fatty acids (Δ5-UPIFA) were established, confirming previous
studies in which they were identified by their equivalent chainlengths (ECL) and by comparison with related authentic standards.
These acids were:cis-5,cis-9 18∶2,cis-5,cis-9,cis-12 18∶3 (P. pinaster),cis-5,cis-9,cis-12,cis-15 18∶4 (C.lawsoniana),cis-5,cis-11 20∶2,cis-5,cis-11,cis-14 20∶3 (all species),cis-5,cis-11,cis-14,cis-17 20∶4 (B. orientalis) acids. In addition,cis-9 18∶1,cis-9,cis-12 18∶2 (all species) andcis-9,cis-12,cis-15 18∶3 (Cupressaceae) acids, together with their elongation products [cis-11 20∶1,cis-11,cis-14 20∶2 (all species) andcis-11,cis-14,cis-17 20∶3 (B. orientalis) acids] were also identified. In the mass spectra, DMOX derivatives of all Δ5-UPIFA showed an intense peak atm/z 153, which is a diagnostic ion of fatty acid derivatives with a Δ5-ethylenic bond. Other double bonds were localized by ion
pairs that differed by 12 atomic mass units. The present study fully justifies the use of ECL to identify Δ5-UPIFA in Conifer
seed oils, in which they are ordinary components. 相似文献
109.
JD Fritz I Danko SL Roberds KP Campbell JS Latendresse JA Wolff 《Canadian Metallurgical Quarterly》1995,37(6):693-700
The expression of full-length dystrophin and various dystrophin deletion mutants was monitored in mdx mouse muscle after intramuscular injection of dystrophin-encoding plasmid DNAs. Recombinant dystrophin proteins, including those lacking either the amino terminus, carboxyl terminus, or most of the central rod domain, showed localization to the plasma membrane. This suggests that there are multiple attachment sites for dystrophin to the plasma membrane. Only those constructs containing the carboxyl terminus were able to stabilize dystrophin-associated proteins (DAP) at the membrane, consistent with other studies that suggest that this domain is critical to DAP binding. Colocalization with DAP was not necessary for membrane localization of the various dystrophin molecules. However, stabilization and co-localization of the DAP did seem to be a prerequisite for expression and/or stabilization of mutant dystrophins beyond 1 wk and these same criteria seemed important for mitigating the histopathological consequences of dystrophin deficiency. 相似文献
110.
Carew Tania Giovannetti; Lamar Melissa; Cloud Blaine S.; Grossman Murray; Libon David J. 《Canadian Metallurgical Quarterly》1997,11(3):400
The underlying mechanisms for impaired output on letter (F, A, and S) and category (e.g., animal) word list generation (WLG) tasks in subcortical ischemic vascular dementia (IVD) were investigated. Normal control (NC) and Alzheimer's disease (AD) participants were also studied. IVD and NC participants performed better on category than letter WLG tasks, whereas the opposite was observed among AD participants. IVD participants produced fewer responses than AD participants on letter WLG tasks, but there was no difference between AD and IVD participants on the "animal" WLG task. AD participants scored lower than IVD and NC participants on animal WLG indexes measuring semantic knowledge. There were few differences between IVD and NC participants. The reduced output on the animal WLG task for IVD participants is consistent with search-retrieval deficits. The reduced output of AD participants may be caused by degraded semantic knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献