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排序方式: 共有1790条查询结果,搜索用时 218 毫秒
191.
Jeffrey Considine Matthias Fitzi Matthew Franklin Leonid A. Levin Ueli Maurer David Metcalf 《Journal of Cryptology》2005,18(3):191-217
This paper considers unconditionally secure protocols for reliable
broadcast among a set of n players, where up to t of the
players can be corrupted by a (Byzantine) adversary but the remaining
h = n - t players remain honest.
In the standard model with a complete, synchronous network of bilateral
authenticated communication channels among the players, broadcast
is achievable if and only if 2n/h < 3. We show that, by extending this model by the existence of partial broadcast channels among subsets of b players, global
broadcast can be achieved if and only if the number h of honest
players satisfies 2n/h < b + 1. Achievability is demonstrated
by protocols with communication and computation complexities
polynomial in the size of the network, i.e., in the number of
partial broadcast channels. A respective characterization for the
related consensus problem is also given. 相似文献
192.
193.
A Comparison of the Annular Phased Array to Helical Coil Applicators for Limb and Torso Hyperthermia
Hagmann Mark J. Levin Ronald L. Turner Paul F. 《IEEE transactions on bio-medical engineering》1985,(11):916-927
The BSD annular phased array (APA) and miniature annular phased array (MAPA) have been compared to helical coil applicators designed for the trunk and thigh, respectively. All four applicators were tested using both cylindrical saline phantoms and a phantom-filled mannequin. Patterns of deposition were determined using both an implantable electric field probe and local values of the rate of temperature increase. Scattered fields were measured when the APA and trunk helix were used with the phantom-filled mannequin. 相似文献
194.
SS Samaan HR Schumacher T Villanueva R Levin BF Atkinson 《Canadian Metallurgical Quarterly》1994,38(4):582-588
We present the first report in which cells in synovial fluid from a patient with multicentric reticulohistiocytosis (MRH) were studied by immunocytochemistry for correlation with routine light and electron microscopy. MRH cells stained predominantly for lymphocyte-related surface antigens and not for the monocyte marker LEU M3 (CD14). These findings suggest a lymphocytic origin of MRH cells and not a histiocytic origin, as previously suggested. In addition, large numbers of membrane-bound, electron-dense, secretory-type granules were found ultrastructurally in the cytoplasm of these cells. 相似文献
195.
Lawrence Levin Edward Fielding Kevin Ackhurst 《International Journal of Flexible Manufacturing Systems》1993,5(2):143-159
This article focuses on the development of a computer control system for a flexible manufacturing cell. The paper outlines the various modules that are required for a computer control system and elaborates on the development of some of these modules. This is part of an ongoing research project at the University of the Witwatersrand. The aim of the project is to demonstrate the viability of flexible manufacturing systems to South African industry. Thus the main constraints of the project were cost, ease of implementation, and ease of maintainability. This necessitated the use of existing machinery and of computer systems and software that were readily available and already familiar to industry. 相似文献
196.
197.
Martin K Kuhlmann Maki Yoshino Nathan W Levin 《Hemodialysis international. International Symposium on Home Hemodialysis》2004,8(4):394-399
Mortality rates among hemodialysis patients differ greatly among the United States, Europe, and Japan and it has been hypothesized that this is mainly due to differences in practice patterns. Results from the international DOPPS study, however, indicate that differences in practice patterns among the United States, Japan, and Europe are small and not alone explanatory for the differences in mortality rates. Ethnic variability in predisposition to atherosclerotic cardiovascular disease in the general population may lead to significant differences in background cardiovascular mortality in the United States, Japan, and Europe. It is our hypothesis that cardiovascular mortality in dialysis patients is to a great extent dependent on cardiovascular background mortality of the general population. We are currently studying the relationship between all‐cause and cardiovascular death rates in countries worldwide using the WHO database. Preliminary data from 35 countries show that all‐cause and cardiovascular death rates differ significantly among regions, with Eastern European countries reporting four‐ to sevenfold higher death rates than Asian countries. A strong linear relationship between cardiovascular and all‐cause death rates is observed among these countries. The next step of our study will be to compare country‐specific cardiovascular death rates of dialysis populations with those of the respective general populations. Ethnic differences in cardiovascular morbidity and mortality may be explained by genetic variability based upon polymorphism of genes involved in the pathogenesis of atherosclerosis and myocardial infarction. 相似文献
198.
Mammalian DNA ligases 总被引:1,自引:0,他引:1
DNA joining enzymes play an essential role in the maintenance of genomic integrity and stability. Three mammalian genes encoding DNA ligases, LIG1, LIG3 and LIG4, have been identified. Since DNA ligase II appears to be derived from DNA ligase III by a proteolytic mechanism, the three LIG genes can account for the four biochemically distinct DNA ligase activities, DNA ligases I, II, III and IV, that have been purified from mammalian cell extracts. It is probable that the specific cellular roles of these enzymes are determined by the proteins with which they interact. The specific involvement of DNA ligase I in DNA replication is mediated by the non-catalytic amino-terminal domain of this enzyme. Furthermore, DNA ligase I participates in DNA base excision repair as a component of a multiprotein complex. Two forms of DNA ligase III are produced by an alternative splicing mechanism. The ubiqitously expressed DNA ligase III-alpha forms a complex with the DNA single-strand break repair protein XRCC1. In contrast, DNA ligase III-beta, which does not interact with XRCC1, is only expressed in male meiotic germ cells, suggesting a role for this isoform in meiotic recombination. At present, there is very little information about the cellular functions of DNA ligase IV. 相似文献
199.
B. P. Yefimov G. Ya. Levin 《Journal of Infrared, Millimeter and Terahertz Waves》1997,18(11):2195-2203
Physical principles of designing continuous action BWT type vacuum generators radiating microwave energy simultaneously at several carrier frequencies in a MMD are described. The control of the output level and frequency in every band are considered. The resonance properties of the sections of periodical structures and the focusing of electron beams in an inhomogeneous magnetic field are used in the generators. The operating characteristics and output device parameters are given. 相似文献
200.
Selection of Universal Primers for PCR Quantification of Total Bacteria Associated With Fish Fillets
An optimal universal primer pair DG74/RW01 for quantitative PCR detection of the mixed bacterial flora from fish fillets was selected from five pairs of primers. The minimum detection limits with GelStar™ and ethidium bromide (EB) used as agarose stains for DNA bands with these primers were found to be 5 and 1 × 102 CFU/PCR, respectively. The liner range of DNA amplification was from 50 to 1 × 105 with GelStar™ and from 5 × 102 to 1 × 105 with EB. 相似文献