Discrimination of confusing characters is very important in recognition of character sets containing a multitude of similar characters. Confusing characters have very similar shapes and are separated by only a small difference. For a successful discrimination, we need to focus on that difference. However, the small difference can be reduced or even lost during the feature extraction process. In such a case, further analysis after the feature extraction rarely succeeds. This paper proposes a discriminative nonlinear normalization algorithm to improve discrimination ability. The proposed method emphasizes the difference between confusing characters. It measures the importance of each region in the discrimination of confusing characters. Then, it resamples the image according to the regional importance measure. As a result, it expands important regions but shrinks less important regions. Since it emphasizes important regions in the preprocessing step, it does not suffer from the information loss during the feature extraction. In experiments, the proposed method successfully detected and expanded important regions. In handwritten Hangul recognition, the proposed method outperformed other two recently developed pair-wise discrimination methods. On SERI95a data set, it improved the recognition rate from 87.69 to 90.11 %, achieving a 19.66 % error reduction rate. 相似文献
K(Nb1?xMnx)O3 (KN1?xMx) ceramics with 0.005 ≤ x ≤ 0.015 were sintered at 1020°C through a normal sintering process without the formation of a liquid phase. They exhibited double polarization versus electric field (P–E) hysteresis and sprout‐shaped strain versus electric field (S–E) curves owing to the presence of a defect dipole (PD), which was formed between the acceptor Mn3+ ion and the oxygen vacancy. Moreover, the aging process was not required to develop the PD. The KN1?xMx ceramics exhibited a large strain of ~0.2% at 6.0 kV/mm. For the KN0.985M0.015 ceramic, this large strain was maintained after 104 cycles of an electric field of 6.0 kV/mm. This ceramic also maintained a double hysteresis curve at 200°C. Therefore, the KN0.985M0.015 ceramic has a large electric field‐induced strain, along with good thermal and fatigue properties for multilayer piezoelectric actuators. 相似文献
Isoflavonoids are a characteristic family of natural products in legumes known to mediate a range of plant-biotic interactions. For example, in soybean (Glycine max: Fabaceae) multiple isoflavones are induced and accumulate in leaves following attack by Spodoptera litura (Lepidoptera: Noctuidae) larvae. To quantitatively examine patterns of activated de novo biosynthesis, soybean (Var. Enrei) leaves were treated with a combination of plant defense elicitors present in S. litura gut content extracts and L-α-[13C9, 15N]phenylalanine as a traceable isoflavonoid precursor. Combined treatments promoted significant increases in 13C-labeled isoflavone aglycones (daidzein, formononetin, and genistein), 13C-labeled isoflavone 7-O-glucosides (daidzin, ononin, and genistin), and 13C-labeled isoflavone 7-O-(6″-O-malonyl-β-glucosides) (malonyldaidzin, malonylononin, and malonylgenistin). In contrast levels of 13C-labeled flavones and flavonol (4′,7-dihydroxyflavone, kaempferol, and apigenin) were not significantly altered. Curiously, application of fatty acid-amino acid conjugate (FAC) elicitors present in S. litura gut contents, namely N-linolenoyl-L-glutamine and N-linoleoyl-L-glutamine, both promoted the induced accumulation of isoflavone 7-O-glucosides and isoflavone 7-O-(6″-O-malonyl-β-glucosides), but not isoflavone aglycones in the leaves. These results demonstrate that at least two separate reactions are involved in elicitor-induced soybean leaf responses to the S. litura gut contents: one is the de novo biosynthesis of isoflavone conjugates induced by FACs, and the other is the hydrolysis of the isoflavone conjugates to yield isoflavone aglycones. Gut content extracts alone displayed no hydrolytic activity. The quantitative analysis of isoflavone de novo biosynthesis, with respect to both aglycones and conjugates, affords a useful bioassay system for the discovery of additional plant defense elicitor(s) in S. litura gut contents that specifically promote hydrolysis of isoflavone conjugates. 相似文献
The thermal expansion and ionic conduction of 15 mol% CaO‐stabilized zirconia (CSZ) with added Al2O3 were investigated. Specimens with 0.5 and 1 mol% Al2O3 maintained the cubic phase, and the thermal diffusivity increased from 0.499 to 0.661 mm2/s with a 1 mol% addition. The addition of 5 mol% caused a decrease in the thermal diffusivity (0.609 mm2/s) with the formation of the monoclinic phase. The thermal expansion coefficient of the CSZ decreased, and the thermal diffusivity increased with the addition of Al2O3. The ionic conductivity was increased up to the addition of 1 mol% due to scavenging of siliceous by Al2O3, while the 5 mol% addition showed a decrease in conductivity with the formation of the intergranular phase. 相似文献
This study aimed to evaluate the kinematics and kinetics of the lower limb in both the intact and amputated leg in individuals with transtibial amputations wearing Energy storage and return feet (ESRFs) with fixed ankles and Prosthetic feet with adaptive ankles (PFAAs) during level walking. Three individuals with transtibial amputations walked on level ground wearing their own ESRFs and PFAAs. Spatiotemporal parameters, kinematics, and kinetics of the lower-extremity joints were measured in the amputated and intact legs. There were differences in the kinematics of the joints in the amputated leg and of the ankle in the intact leg between ESRFs and PFAAs. Differences in joint moments, power, and stiffness in most joints in both legs and braking impulse were found between ESRFs and PFAAs. Thus, although it was a pilot study with three subjects, ankle angle control mechanisms (ESRFs: Fixed ankle vs. propriofoot: Mechanical motor vs. élan and echelon: Hydraulic actuator) might affect biomechanical features during level walking.
Efficient numerical method is developed for the prediction of aerodynamic noise generation and propagation in low Mach number
flows such as aeolian tone noise. The proposed numerical method is based on acoustic/viscous splitting techniques of which
acoustic solvers use simplified linearised Euler equations, full linearised Euler equations and nonlinear perturbation equations
as acoustic governing equations. All of acoustic equations are forced with immersed surface dipole model which is developed
for the efficient computation of aerodynamic noise generation and propagation in low Mach number flows in which dipole source,
originating from unsteady pressure fluctuation on a solid surface, is known to be more efficient than quadrupole sources.
Multi-scale overset grid technique is also utilized to resolve the complex geometries. Initially, aeolian tone from single
cylinder is considered to examine the effects that the immersed surface dipole models combined with the different acoustic
governing equations have on the overall accuracy of the method. Then, the current numerical method is applied to the simulation
of the aeolian tones from twin cylinders aligned perpendicularly to the mean flow and separated 3 diameters between their
centers. In this configuration, symmetric vortices are shed from twin cylinders, which leads to the anti-phase of the lift
dipoles and the in-phase of the drag dipoles. Due to these phase differences, the directivity of the fluctuating pressure
from the lift dipoles shows the comparable magnitude with that from the drag dipoles at 10 diameters apart from the origin.
However, the directivity at 100 diameters shows that the lift-dipole originated noise has larger magnitude than, but still
comparable to, that of the drag-dipole one. Comparison of the numerical results with and without mean flow effects on the
acoustic wave emphasizes the effects of the sheared background flows around the cylinders on the propagating acoustic waves,
which is not generally considered by the classic acoustic analogy methods. Through the comparison of the results using the
immersed surface dipole models with those using point sources, it is demonstrated that the current methods can allow for the
complex interactions between the acoustic wave and the solid wall and the effects of the mean flow on the acoustic waves. 相似文献
A femtosecond (fs) terahertz (THz) linac has been constructed to generate fs-THz radiation by using ultrashort electron beam at the Pohang Accelerator Laboratory. To generate an ultrashort electron beam with 60-MeV energy, a chicane bunch compressor has been adopted. Simulation studies have been conducted to design the linac. In this note, recent achievements at 60-MeV linac are presented. 相似文献
A three-dimensional numerical model for fluid flow was solved by computer for the continuous thin slab casting process with an electromagnetic brake system. The effects of the electromagnetic brake on the meniscus properties and solidified shell thickness were investigated along with the flow pattern. The electromagnetic brake reduced the jet stream velocities of the liquid steel but increased the amount of the upper stream. It contributed to the increase of the velocity and temperature on the meniscus. It eliminated the cold spot region that generally exists at the rear of the nozzle, the optimum required electromagnetic current for this effect being calculated to be 200 amperes. The average solidified shell thickness was improved by the application of the electromagnetic force. 相似文献