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排序方式: 共有2033条查询结果,搜索用时 15 毫秒
101.
Gao Xiao-Zhi Nalluri Madhu Sudana Rao Kannan K. Sinharoy Diptendu 《中国科学:技术科学(英文版)》2021,64(3):508-520
With the pervasive generation of information from a wide range of sensors and devices, there always exist a large number of input features in databases, thus complicating machine learning problem formulation. However, certain features are relatively impertinent to specific problems, which may degrade the performances of classifiers in terms of prediction accuracy, sensitivity,specificity, and recall rate. The main goal of a multi-objective optimization problem is to identify the subsets of the given features. To this end, a hybrid cat swarm optimization(HCSO) algorithm is proposed in our paper for performance improvement of the basic cat swarm optimization(CSO) that incorporates guided and competitive inherent characteristics into the original CSO. The performance of HCSO has been tested by finding the optimal feature subset for 15 benchmark datasets. The number of class labels for these datasets varies between 2 and 40. The time complexity analysis of both CSO and HCSO has also been evaluated. Moreover, the performance of the proposed algorithm has been compared with that of simple CSO and other state-ofthe-art techniques. The performances obtained by HCSO have an average 2.68% improvement with a standard deviation of 2.91.The maximum performance improvement is up to 10.09% in prediction accuracy. Tested on the same datasets, CSO has yielded improvements within the range of-7.27% to 8.51% with an average improvement 0.9% and standard deviation 3.96. The statistical tests carried out in the experiments prove that HCSO manifests a moderately better feature selection capacity than that of its counterparts. 相似文献
102.
Jiji Abraham Krishnan Sidhardhan Sisanth Ajesh Kulamamvila Zachariah Hanna Joseph Mariya Soney C. George Nandakumar Kalarikkal Sabu Thomas 《应用聚合物科学杂志》2020,137(46):49429
Obtaining strong interfacial interaction between filler and polymer matrix is very crucial for the fabrication of polymer nanocomposites with superior performance. Present study is aimed to fabricate high performance styrene butadiene rubber (SBR) nanocomposites with imidazolium type ionic liquid modified multiwalled carbon nanotube (MWCNT). Ionic liquid facilitates the dispersion of MWCNT in rubber matrix and it is obvious from transmission electron microscopy images. Diffusion of toluene through SBR nanocomposite membranes has been investigated as a function of surface modified MWCNT (f-MWCNT) content to analyze the chain dynamics and filler-polymer interactions. O2 gas barrier effect of nanocomposites with special reference to the filler loading is explored. The substantial improvement in the barrier effect in presence of filler interpreted on the grounds of a theoretical model describing permeability of heterogeneous systems. Finally solvent sensing characteristics of prepared nanocomposites are also analyzed and it is observed that prepared nanocomposites can be used as a flexible solvent sensor. 相似文献
103.
Based onin-situ Mössbauer and X-ray diffraction studies, it is shown that in the Fe/TiO2 catalyst, the anatase-rutile transformation of the TiO2 support is facilitated by the Fe2+ ions formed during the reduction. The transformation occurs at lower temperatures in Th/TiO2 and Cu/TiO2 compared to pure TiO2. In general, the transformation of anatase to rutile seems to occur at or below the temperature (770 K) at which strong-metal-support-interaction manifests itself.Contribution No. 718 from the Solid State and Structural Chemistry Unit. 相似文献
104.
Noriah Bidin Siti Radhiana Azni Shumaila Islam Mundzir Abdullah M. Fakaruddin Sidi Ahmad Ganesan Krishnan A. Rahman Johari M. Aizat A. Bakar Nur Syahirah Sahidan NurFatin Musa M. Farizuddin Salebi Naqiuddin Razali Mohd Marsin Sanagi 《International Journal of Hydrogen Energy》2017,42(26):16325-16332
Hydrogen production via water electrolysis was studied under the effect of magnetic and optical field. A diode solid state laser at blue, green and red were utilized as optical field source. Magnetic bar was employed as external magnetic field. The green laser has shown a greatest effect in hydrogen production due to its non-absorbance properties in the water. Thus its intensity of electrical field is high enough to dissociation of hydronium and hydroxide ions during orientation toward polarization of water. The potential to break the autoprotolysis and generate the auto-ionization is the mechanism of optical field to reveal the hydrogen production in water electrolysis. The magnetic field effect is more dominant to enhance the hydrogen production. The diamagnetic property of water has repelled the present of magnetic in water. Consequently the water splitting occurs due to the repulsive force induced by the external magnetic field. The magnetic distributed more homogenous in the water to involve more density of water molecule. As a result hydrogen production due to magnetic field is higher in comparison to optical field. However the combination both fields have generated superior effect whereby the hydrogen yields nine times higher in comparison to conventional water electrolysis. 相似文献
105.
Sorption of elemental mercury by activated carbons 总被引:1,自引:0,他引:1
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108.
Sree Hari Krishnan Parthasarathi R. Padmanabhan Hema A. Murthy 《International Journal of Speech Technology》2011,14(4):361-368
This paper demonstrates the robustness of group delay based features to additive noise. First, we analytically show the robustness
of group delay based representations. The analysis makes use of the fact that, for minimum-phase signals, the group delay
function can be represented in terms of the cepstral coefficients of the log-magnitude spectrum. Such a representation results
in the speech spectrum dominating over the noise spectrum, both at low and high SNRs. Further, we experimentally demonstrate
the robustness of the representation on a voice activity detection (VAD) task, comparing a group delay based VAD algorithm
with standard VAD methods as well as a magnitude-spectrum based method. 相似文献
109.
L. Satyanarayan Anish Kumar T. Jayakumar C. V. Krishnamurthy Krishnan Balasubramaniam Baldev Raj 《Journal of Nondestructive Evaluation》2009,28(3-4):111-124
New techniques developed using the array transducer, to image and size the bottom-surface and near-through-wall crack-like defects in thick carbon steel components are discussed. Three studies are reported here including (a) Optimal beam steering angle for focused and unfocused inspection using phased array method for bottom-surface crack sizing. (b) A front wall correction algorithm for sizing of near-through-wall crack-like defects. (c) A small aperture technique for sizing of near-through-wall crack-like defects. A Finite Difference Time Domain (FDTD) based simulation was used to study and verify the experimental observations. The application of time domain scheme relative arrival time technique (RATT), to measure the size of the near-through wall crack-like defects for the leak before break (LBB) criterion, was also investigated and found to be insufficient. A conventional SAFT algorithm was used for improving the sizing using the small aperture technique. 相似文献
110.
We present transmission electron microscopy observations of domain wall motion in thin freestanding KNbO 3 crystals under applied electric fields. Since there is no substrate, there is no elastic clamping of 90 domains. We observe that curved and tilted 90 domain walls are the most mobile, whereas untilted 90 domain walls are resistant to field-induced motion. We explain this result in terms of two factors. First, the switching pressure on a domain wall ( P 2 m P 1 ) E is determined by the relative electrostatic energies of the neighboring polarizations P 1 and P 2 . Consequently, some 90 domain walls are immobile under certain field directions, leading to domain interlocking. Second, domain walls experiencing a high switching pressure move by a ripple mechanism, and do not move as rigid sheets. The tilted wall region in such a ripple has a polarization charge, and an associated depolarization field, which reduces the local switching barrier. An accumulation of polarization charge can result in a tilted or curved wall, as occurs at the mobile tips of 90 domain needles. Any increase in density of immobile wall configurations with cycle time represents an inherent contribution to fatigue. Uniaxial ferroelectrics, with polarizations parallel to the field, should not experience such domain interlocking. 相似文献