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81.
82.
A genetic algorithm-based method for feature subset selection 总被引:5,自引:2,他引:3
Feng Tan Xuezheng Fu Yanqing Zhang Anu G. Bourgeois 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2008,12(2):111-120
As a commonly used technique in data preprocessing, feature selection selects a subset of informative attributes or variables
to build models describing data. By removing redundant and irrelevant or noise features, feature selection can improve the
predictive accuracy and the comprehensibility of the predictors or classifiers. Many feature selection algorithms with different
selection criteria has been introduced by researchers. However, it is discovered that no single criterion is best for all
applications. In this paper, we propose a framework based on a genetic algorithm (GA) for feature subset selection that combines
various existing feature selection methods. The advantages of this approach include the ability to accommodate multiple feature
selection criteria and find small subsets of features that perform well for a particular inductive learning algorithm of interest
to build the classifier. We conducted experiments using three data sets and three existing feature selection methods. The
experimental results demonstrate that our approach is a robust and effective approach to find subsets of features with higher
classification accuracy and/or smaller size compared to each individual feature selection algorithm. 相似文献
83.
Anu Disney Dhominic Jayapaul A. Merline 《International Journal of Communication Systems》2023,36(7):e5456
Cell planning in conventional networks has gained more attention as it directly affects the network performance and deployment cost. Existing cell planning methodologies are framed either with identical base stations or constructing a network without any infrastructure. But heterogeneous networks (HetNets) allow the service provider to deploy small cells over the region to enhance the network performance and signal coverage probability. Thus, a small-cell planning procedure is presented in this research work considering the low-powered base station and deployment cost to enhance the energy efficiency of the HetNet. An adaptive fuzzy expert system is used for cell dimensioning, and a nature-inspired ant colony optimization model is employed for automatic base station placement. Simulation analysis demonstrates that the proposed small-cell planning procedure attains better energy efficiency and user satisfaction ratio compared to conventional planning strategies. In the two cases of simulation analysis, the proposed model attains an average of 85% user satisfaction ratio for case 1 and 87% for case 2, which is better than existing strategies like density-based spatial clustering of applications with noise (DBSCAN), k-means, and number-based spatial clustering (NBSC) algorithms. 相似文献
84.
Wiley Jenny L.; LaVecchia Kari L.; Karp Natalie E.; Kulasegram Sanjitha; Mahadevan Anu; Razdan Raj K.; Martin Billy R. 《Canadian Metallurgical Quarterly》2004,12(3):173
Efforts to determine whether Δ?-tetrahydrocannabinol (Δ?-THC) and anandamide elicit similar discriminative stimulus effects have yielded conflicting results. The difficulty in establishing a discriminative cue to anandamide may be due to its metabolic instability. Rats were trained to discriminate either Δ?-THC or O-1812, a metabolically stable anandamide analog, from vehicle to avoid this issue. O-1812 and Δ?-THC substituted for each other; however, both drugs were more potent in the O-1812-trained rats. Further, O-1812 only substituted for Δ?-THC at response rate decreasing doses. The CB? antagonist, SR141716A, blocked the discriminative stimulus effects of both drugs but augmented their rate effects. O-1839, a VR? agonist, failed to substitute for either cannabinoid. These results suggest that the discriminative stimulus effects of Δ?-THC and O-1812 are similar, but subtle differences also exist. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
85.
The antioxidant activities of the flavonol aglycones, quercetin and myricetin, and their selected glycosides were compared
in bulk methyl linoleate oxidized at 40°C. Methyl linoleate hydroperoxide formation, hydroperoxide isomer distribution, and
ketodiene formation were followed by using high-performance liquid chromatography (HPLC) analysis. The aglycones, quercetin
and myricetin, were consistently more active in bulk methyl linoleate than their glycosides and more active than α-tocopherol
at 500 and 1000 μM. At 50 μM, the order of activity was myricetin > α-tocopherol > quercetin, and the order of activity of
quercetin and its derivatives was quercetin > quercitrin > isoquercitrin > rutin. Myricitrin was slightly less active than
myricetin. The sugar moiety was shown to have a marked effect on the antioxidant activity of flavonols. The rhamnoside derivatives,
quercitrin and myricitrin, both possessed activity close to that of their corresponding aglycones. The different activities
of glycosides could be partly explained by different solubilities and by differences in oxidizability of glycosides containing
a monosaccharide or disaccharide at the C3 position. The effect on hydroperoxide isomer distribution indicates that α-tocopherol was a more effective hydrogen donor
than flavonoids, although flavonoids were more effective in inhibiting oxidation of methyl linoleate. 相似文献
86.
Anu M. Turpeinen Georg Alfthan Liisa Valsta Eino Hietanen Jukka T. Salonen Hanna Schunk Kristiina Nyyssönen Marja Mutanen 《Lipids》1995,30(6):485-492
The effects of natural mixed diets on lipid peroxidation were investigated in humans. In the first study, 59 subjects were
fed a rapeseed oil-based diet rich in monounsaturated fatty acids (MUFA) and a sunflower oil-based diet rich in polyunsaturated
fatty acids (PUFA) in a cross-over manner for three and a half weeks. The lipid peroxidation products in plasma were determined
by measuring conjugated dienes and malondialdehyde (MDA). In a second study, plasma thiobarbituric acid reactive substances
(TBARS), lipid hydroperoxides, and the susceptibility of very low density lipoprotein + low-density lipoprotein (LDL) toin vitro oxidation were measured from subjects fed similar MUFA and PUFA diets for six week diets. No significant differences in plasma
MDA or conjugated diene concentrations were found after the rapeseed oil diet or the sunflower oil diet in Study 1. In the
second study, a small but significant decrease (P<0.05) in both lipid hydroperoxides and TBARS was observed in the LDL fraction after the sunflower oil diet. Thein vitro oxidation gave opposite results, showing increased oxidation after the sunflower oil diet. Despite a high intake of α-tocopherol
during the oil peroids, no increase in plasma α-tocopherol was noticed in either study. The results suggest that moderate
changes in the fatty acid composition in the Western-type diet may be adequate to affect lipoprotein susceptibility to oxidationin vitro, but there is considerable disparity with some indices ofin vivo lipid peroxidation. 相似文献
87.
Sunil Anu Sharma Pavan Kumar Bharti R.G. Shandil 《International Journal of Mechanical Sciences》2007,49(9):1047-1059
This paper deals with the theoretical investigation of the double-diffusive convection in a micropolar ferromagnetic fluid layer heated and soluted from below saturating a porous medium subjected to a transverse uniform magnetic field. For a flat fluid layer contained between two free boundaries, an exact solution is obtained. A linear stability analysis theory and normal mode analysis method have been carried out to study the onset of convection. The influence of various parameters like medium permeability, solute gradient, non-buoyancy magnetization and micropolar parameters (i.e. coupling parameter, spin diffusion parameter and micropolar heat conduction parameter) has been analyzed on the onset of stationary convection. The critical magnetic thermal Rayleigh number for the onset of instability is also determined numerically for sufficiently large values of buoyancy magnetization parameter M1 and results are depicted graphically. The principle of exchange of stabilities is found to hold true for the micropolar ferromagnetic fluid saturating a porous medium heated from below in the absence of micropolar viscous effect, microinertia and solute gradient. The oscillatory modes are introduced due to the presence of the micropolar viscous effect, microinertia and solute gradient, which were non-existent in their absence. In this paper, an attempt is also made to obtain the sufficient conditions for the non-existence of overstability. 相似文献
88.
The photoinduced polarization in 75 MeV oxygen ion irradiated (fluence: 1.8 × 1011, 1.8 × 1012 and 1.8 × 1013 ions/cm2) kapton-H polyimide has been investigated by analyzing charge decay characteristics for different polarizing parameters viz. electric fields (40 to 600 kV/cm), temperature (40 to 250 °C) and illumination intensity (1200 to 2800 1x). The fields induced as well as thermal ionization of excitons under illumination are the main causes which provide photopolarization. The charge decay spectra reveal the presence of both shallow and deep trapping sites in pristine and irradiated kapton-H polyimide. The variation in the photopolarization with fluence shows the occurrence of secondary radiation induced crystallinity (SRIC). The SRIC is also responsible for the increase in initial current (I0P) with intensity of illumination in low fluence irradiated samples. A decrease in I0P with intensity of illumination in high fluence irradiated samples has been associated to the conversion of trapping sites into recombination centers. 相似文献
89.
Jiantao Pu Yagnanarayanan Kalyanaraman Subramaniam Jayanti Karthik Ramani Zygmunt Pizlo 《Computer Graphics and Applications, IEEE》2007,27(4):38-47
Due to increasing product design complexities and the ever-expanding variety of product parts, the amount of information that designers must catalog has exploded. Accordingly, capable CAD tools to help designers create engineering artifacts are now pervasive. The volume of such engineering artifacts generated has increased exponentially and enterprises spend huge resources to organize and archive them into repositories. In these large design repositories, traditional text-based searches prove unwieldy and impractical, and are thus insufficient for individuals seeking 3D content. The paper explains that while traditional text-based searches are impractical for users seeking 3D content in large repositories, existing 3D search systems present search results in a 1D list, which is hard to search. A new interaction paradigm lets users navigate results in 2D and 3D spaces and easily find 3D models that are similar overall or in a single orientation. 相似文献
90.
An antibody-based solid-phase extraction method for filtered 384-well plates was developed for a medical drug candidate having two enantiomeric forms in order to demonstrate the potential of the use of recombinant antibody fragments as specific and efficient immunosorbents. An immobilization method using a six-histidine tag of the antibody fragment and mild oxidation was applied in order to immobilize antibody fragments in an oriented and kinetically stable way that ensured high capacity of the antibody support. Phosphate buffer or plasma spiked with enantiomers were used as samples. Selective solid-phase extraction was followed by liquid chromatography-mass spectrometry analysis. Average recoveries for buffer and plasma samples ranged from 79 to 122% and 80 to 108%, respectively. Good linearity was observed in the concentration range of 30-3000 ng/mL of the enantiomer. 相似文献