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排序方式: 共有264条查询结果,搜索用时 15 毫秒
1.
A fuzzy logic based-method for prognostic decision making in breast and prostate cancers 总被引:1,自引:0,他引:1
Seker H. Odetayo M.O. Petrovic D. Naguib R.N.G. 《IEEE transactions on information technology in biomedicine》2003,7(2):114-122
Accurate and reliable decision making in oncological prognosis can help in the planning of suitable surgery and therapy, and generally, improve patient management through the different stages of the disease. In recent years, several prognostic markers have been used as indicators of disease progression in oncology. However, the rapid increase in the discovery of novel prognostic markers resulting from the development in medical technology, has dictated the need for developing reliable methods for extracting clinically significant markers where complex and nonlinear interactions between these markers naturally exist. The aim of this paper is to investigate the fuzzy k-nearest neighbor (FK-NN) classifier as a fuzzy logic method that provides a certainty degree for prognostic decision and assessment of the markers, and to compare it with: 1) logistic regression as a statistical method and 2) multilayer feedforward backpropagation neural networks an artificial neural-network tool, the latter two techniques having been widely used for oncological prognosis. In order to achieve this aim, breast and prostate cancer data sets are considered as benchmarks for this analysis. The overall results obtained indicate that the FK-NN-based method yields the highest predictive accuracy, and that it has produced a more reliable prognostic marker model than both the statistical and artificial neural-network-based methods. 相似文献
2.
Unsaturated Polyester resins were prepared by the reaction of cinnamylsuccinic acid with saturated diols, namely, ethylene, diethylene, propylene, dipropylene, tetramethylene, and hexamethylene glycols, and the unsaturated diols, namely, 1,4-butene- and 1,4-butynediols. All the polyester resins obtained have been characterized and were found to cure with styrene, with relatively low conversions. The properties of the cured polyesters in the form of films were determined. IR and 1H-NMR spectroscopy were used for both qualitative and quantitative analyses of the polyesters and their hydrolyzate products, after curing with styrene. 相似文献
3.
N‐p‐Bromophenylmaleimide (BrPMI) does not polymerize in solution by conventional free radical mechanism. However, it readily polymerized in bulk when mixed with a free radical initiator and heated in a microwave oven for 7–8 min. Copolymerization of ethyl methacrylate or butyl methacrylate with BrPMI was conducted in dioxane. The copolymers were characterized by IR and 1H NMR spectroscopy and gel permeation chromatography. The monomer reactivity ratios were calculated by a non‐linear least‐square analysis. Thermal analysis indicated a great improvement in thermal stability of the copolymers compared with the methacrylate homopolymers. BrPMI was also polymerized in bulk in the DSC pan, which allowed the calculation of the activation energy of its polymerization. Copyright © 2003 Society of Chemical Industry 相似文献
4.
S. H. El-Hamouly N. N. Messiha K. N. Abd El Nour 《Journal of Materials Science》1994,29(10):2784-2788
The copolymerization of tri-n-butyl tin acrylate (TBTA) with methylmethacrylate (MMA) has been investigated in dioxane. The composition of these copolymers was determined quantitatively by 1H nuclear magnetic resonance (NMR) spectroscopy. The tin contents were estimated by gravimetric as well as thermogravimetric techniques (TGA). The reactivity ratio of such copolymers was estimated by application of the Kelen-Tudos method. The dielectric properties of the copolymers have been studied over a frequency range of 100–50 kHz at different temperatures from 20 to 70°C. The electrical conductivity for such copolymers was also measured. The results are interpreted in terms of the tin content of the copolymers. 相似文献
5.
Gesbert D. Shafi M. Da-shan Shiu Smith P.J. Naguib A. 《Selected Areas in Communications, IEEE Journal on》2003,21(3):281-302
This paper presents an overview of progress in the area of multiple input multiple output (MIMO) space-time coded wireless systems. After some background on the research leading to the discovery of the enormous potential of MIMO wireless links, we highlight the different classes of techniques and algorithms proposed which attempt to realize the various benefits of MIMO including spatial multiplexing and space-time coding schemes. These algorithms are often derived and analyzed under ideal independent fading conditions. We present the state of the art in channel modeling and measurements, leading to a better understanding of actual MIMO gains. Finally, the paper addresses current questions regarding the integration of MIMO links in practical wireless systems and standards. 相似文献
6.
BACKGROUND: Rocuronium bromide (ORG 9426) is a new nondepolarizing muscle relaxant with a rapid onset but an intermediate duration of action. The dose-response relationships for neostigmine and edrophonium were studied during antagonism of neuromuscular block induced by rocuronium bromide. METHODS: Sixty-four ASA physical status 1 or 2 adults were given 0.6 mg/kg rocuronium bromide during thiopental-fentanyl-nitrous oxide-isoflurane anesthesia. Train-of-four (TOF) stimulation was applied to the ulnar nerve every 10 s, and the force of contraction of the adductor pollicis muscle was recorded. When spontaneous recovery of first twitch height reached 10% of its initial control value, edrophonium (0.1, 0.2, 0.4, or 1 mg/kg) or neostigmine (0.005, 0.01, 0.02, or 0.05 mg/kg) was administered by random allocation. Neuromuscular function in another eight subjects was allowed to recover spontaneously. Assisted recovery was defined as actual recovery minus mean spontaneous recovery in patients who were not given antagonists. RESULTS: The dose-response curves for neostigmine- and edrophonium-assisted antagonism of rocuronium bromide neuromuscular blockade for the single twitch and TOF ratio were not parallel. The doses of neostigmine required to achieve 50% and 80% recovery (ED50 and ED80, respectively) of the first twitch after 10 min were 0.017 (0.001) and 0.033 (0.001) mg/kg (mean (standard error of estimate for the mean)), respectively. Corresponding ED50 and ED80 values for edrophonium were 0.161 (0.001) and 0.690 (0.001) mg/kg, respectively. These values corresponded to neostigmine:edrophonium potency ratios of 9.5 (0.56) and 21 (0.67) for first twitch ED50 and ED80 height, respectively. The calculated doses producing ED50 of the TOF ratio at 10 min were 0.017 (0.001) and 0.469 (0.001) mg/kg for neostigmine and edrophonium, respectively. These values corresponded to a potency ratio of 27.5 (1.66). CONCLUSIONS: Under the conditions described in this study, if reversal was attempted at 10% first twitch recovery, edrophonium was less capable than neostigmine of reversing fade (potency ratio of 19.2 and 27.5 at 5 and 10 min, respectively) than first twitch (potency ratio of 6.7 and 9.5 at 5 and 10 min, respectively) during antagonism of rocuronium bromide-induced blockade. Edrophonium was found to be less effective than neostigmine at reversing rocuronium bromide-induced TOF fade. 相似文献
7.
The single-particle excitation spectrum and the density of states (DOS) for a superconducting bilayer composite are calculated by solving the Bogoliubov equations. The bilayer consists of two different superconducting films in contact. The superconducting order parameters of the films 1 and 2 are assumed constant. For various film thicknesses the dependence of the DOS on the ratio 1/2 is shown. This dependence is most prominent for states with excitation energy less than 2. 相似文献
8.
The monomer reactivity ratios for the copolymerization of tributyltin acrylate with styrene and allyl methacrylate have been found to be r1 = 0.213, r2 = 1.910 and r1 = 0.195, r2 = 2.257, respectively. Also, the copolymerization parameters of tributyltin methacrylate with styrene and allyl methacrylate were as follows: r1 = 0.256, r2 = 1.104 and r1 = 2.306, r2 = 1.013. Copolymerization reactions were carried out in solution at 70°C using 1 mole % AIBN, and the copolymer compositions were determined by tin analysis. Ternary copolymerization of the three systems butyl methacrylate–tributyltin methacrylate–acrylonitrile, butyl acrylate–tributyltin methacrylate–acrylonitrile, and styrene–tributyltin acrylate–acrylonitrile have been studied, and the terpolymer composition of each system was determined through tin and nitrogen analyses. The variation of instantaneous and average terpolymer composition with conversion fit satisfactorily the experimental results over a wide range of conversion. 相似文献
9.
This article describes the fundamental foaming mechanisms that governed the volume expansion behavior of extruded polypropylene (PP) foams. A careful analysis of extended experimental results indicated that the final volume expansion ratio of the extruded PP foams blown with butane was governed by either the loss of the blowing agent or the crystallization of the polymer matrix. A charge coupling device (CCD) camera was installed at the die exit to carefully monitor the shape of the extruded PP foams. The CCD images were analyzed to illustrate both mechanisms, gas loss and crystallization, during foaming at various temperatures, and the maximum expansion ratio was achieved when the governing mechanism was changed from one to the other. In general, the gas loss mode was dominant at high temperatures and the crystallization mode was dominant at low temperatures. When the gas loss mode was dominant, the volume expansion ratio increased with decreasing temperature because of the reduced amount of gas lost. By contrast, when the crystallization mode was dominant, the expansion ratio increased with increasing temperature because of the delayed solidification of the polymer. The processing window variation with the butane concentration, the change in the temperature ranges for the two governing modes, and the sensitivity of melt temperature variations to the volume expansion ratio are discussed in detail on the basis of the obtained experimental results for both branched and linear PP materials. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2661–2668, 2004 相似文献
10.
Emira Nechadi Mohamed Naguib Harmas Najib Essounbouli Abdelaziz Hamzaoui 《国际自动化与计算杂志》2013,10(4):281-287
Power system stability is enhanced through a novel stabilizer developed around an adaptive fuzzy sliding mode approach which applies the Nussbaum gain to a nonlinear model of a single-machine infinite-bus (SMIB) and multi-machine power system stabilizer subjected to a three phase fault. The Nussbaum gain is used to avoid the positive sign constraint and the problem of controllability of the system. A comparative simulation study is presented to evaluate the achieved performance. 相似文献