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11.
The discrimination problem for two normal populations with the same covariance matrix when additional information on the population is available is considered. A study of the robustness properties against training sample contamination of classification rules that incorporate this additional information is performed. These rules have received recently attention where their total misclassification probability (TMP) is proved to be lower than Fisher's linear discriminant rule. The results of a simulation study on the TMP which compares the behaviour of the new rules against Fisher's rule and some of its robustified versions under different types of contamination are presented. These results show that the rules that incorporate the additional information not only have lower TMP, but they also prevent against some types of contamination. In order to achieve prevention from all types of contamination a robustifed version of these rules is recommended. 相似文献
12.
This paper presents a summary of the mechanical features and the medium term operating experience from three small horizontal axis wind energy conversion systems covering a range of 500 to 5000 Watt, intented for rural and isolated communities. These turbines have a new regulator which reduces gyroscopic loads, is easy to adjust and could be manufactured stronger and in smaller sizes than the conventional tail vanes. It is concluded that is feasible to build cheaps and reliable wind turbine generators with an acceptable efficiency employing common-use elements, but is needed a careful and optimized design. 相似文献
13.
The use of drugs for common pregnancy complications like premature labor, hypertensive diseases, and premature rupture of membranes with chorioamnionitis is reviewed. In addition, new publications on antiviral drugs in HIV-positive pregnant patients are also discussed. Among the drugs, suppressing premature labor side-effects of beta-mimetics are of growing concern. The effectiveness of other agents like magnesium, indomethacin, and sulindac are addressed. The various mechanisms explaining the beneficial effect of magnesium in pre-eclampsia are reviewed and new data on antihypertensives, such as labetalol, calcium channel blockers, and methyldopa are presented. The evidence from various clinical trials on the value of low-dose aspirin as a prophylactic agent against pregnancy-induced hypertension, pre-eclampsia, and intrauterine growth retardation in high-risk and low-risk patients is compared. Pharmacokinetic data including transplacental transfer of antibiotics and anti-HIV nucleosides are part of this review. 相似文献
14.
Solution of temperature fields in hydrodynamics bearings by the numerical network method 总被引:1,自引:0,他引:1
Solution to the 2-D steady-state nonlinear heat conduction equation, involving cylindrical coordinates, applied to a plain bearing by a simple and versatile numerical technique based on network method is presented in this work. These advantages of the technique are necessary for the status evaluation of industrial machines during operation because time and computing resources are limited. The pressure field in the fluid is previously solved from the Reynolds equation by finite element method. The main difficulty is associated with the exponential dependency of the viscosity on temperature. The proposed model is very efficient and requires negligible computing times. Solutions are very close to the experimental and numerical results of other researchers. 相似文献
15.
Jos M. Moreno Maria A. Aramendía Alberto Marinas Jos M. Marinas Francisco J. Urbano 《Applied catalysis. B, Environmental》2005,59(3-4):275-283
The liquid-phase hydrodechlorination of 3-chloropyridine and chlorobenzene has been studied over alkali-modified zirconia-supported palladium catalysts. The modification of the ZrO2 with alkali metal carbonates improves the catalytic activity of the final palladium catalyst. Therefore, the larger the ionic radii (Li+ < Na+ < K+), the greater the catalytic activity (TOF) of the palladium catalyst. For 3-chloropyridine, hydrodechlorination proceeds without catalyst deactivation. This is explained as the result of the interaction of reaction products (pyridine and HCl) forming pyridinium chloride, thus avoiding the detrimental effect of HCl on the palladium particles. Catalytic hydrodechlorination of chlorobenzene over Pd catalysts exhibits an initial catalytic activity (TOF) much lower than that of 3-chloropyridine and the Pd catalysts deactivate as the reaction proceeds. Finally, chlorobenzene hydrodehalogenation has also been carried out in the presence of an equimolecular amount of pyridine resulting in a decrease in the initial reaction rate on the one hand, but also in an increase in final conversion on the other. 相似文献
16.
Sánchez-Meca Julio; Marín-Martínez Fulgencio; Chacón-Moscoso Salvador 《Canadian Metallurgical Quarterly》2003,8(4):448
It is very common to find meta-analyses in which some of the studies compare 2 groups on continuous dependent variables and others compare groups on dichotomized variables. Integrating all of them in a meta-analysis requires an effect-size index in the same metric that can be applied to both types of outcomes. In this article, the performance in terms of bias and sampling variance of 7 different effect-size indices for estimating the population standardized mean difference from a 2 × 2 table is examined by Monte Carlo simulation, assuming normal and nonnormal distributions. The results show good performance for 2 indices, one based on the probit transformation and the other based on the logistic distribution. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
17.
The reaction of LaNi5 with Cu powder during sintering at high temperature was examined in order to obtain better conductivity and ductility. Pressurized and forged copper-LaNi5 pellets were investigated by optical metallography, DTA, XRD and TEM. The need for heat treatment after pressing and/or forging is vital to obtain good diffusion bonding between the copper particles and to improve the material strength. No interaction between La, Ni and Cu were observed after heating at 1173 K but a very stable La2O3 phase was created around the LaNi5 particle. Rolling up to 85% reduction showed good ductility. 相似文献
18.
19.
JF Tomás E Rodriguez-I?igo J Bartolomé A Madejón M Fogeda H Oliva A Moreno JM Fernández-Ra?ada V Carre?o 《Canadian Metallurgical Quarterly》1997,19(10):1053-1057
Long-term effects after blood or bone marrow transplantation (BMT) are emerging as an important issue, as more patients are included in BMT programmes and as this procedure becomes more successful. Long-term liver dysfunction, mainly due to chronic graft-versus-host disease or hepatitis C virus infection, is a well-known complication. Nevertheless, the diagnosis of liver disease in this patient group is sometimes difficult and, despite adequate studies, it may remain undetected. A novel hepatitis-associated virus, hepatitis G virus (HGV), has recently been identified. The virus belongs to the Flaviviridae family and is known to be parenterally transmitted, although there is no clear evidence to implicate this agent in causing acute or chronic hepatitis. We report a patient who developed mild, but persistent, abnormalities in transaminases for 2 years after an autologous BMT. HGV RNA was detected in both serum and liver. HGV RNA persisted in serum for at least 8 months. No other known hepatitis virus was found. This report provides the first direct evidence of a patient with long-term liver abnormalities after a BMT in whom the only known hepatitis virus isolated was the HGV. 相似文献
20.
Vilar Moreno C. Amaris Duarte H. Usaola Garcia J. 《Energy Conversion, IEEE Transaction on》2002,17(2):267-272
Wind energy conversion systems (WECS) produce fluctuating output power, which may cause voltage fluctuations and flicker. Flicker assessment in networks may be difficult since its evaluation requires long computing time and special procedures to calculate the flicker severity index, Pst. In this paper, a frequency domain method to study flicker propagation is presented. This method is based on propagation of frequency components from WECS output currents throughout the grid. In this way, a fast flicker analysis in a network of any size can be performed. Also, an algorithm for flicker measurement in the frequency domain, which allows Pst calculation, is proposed. Several study cases have been performed, and results have been compared with time domain simulations, showing good agreement between them 相似文献