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11.
12.
Wen-Yao Chen Wen-Liang Hwang Tien-Ching Lin 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2006,36(3):649-659
A prototype is representative of a set of similar objects. This paper proposes an approach that formulates the problem of prototype generation as finding the mean from a given set of objects, where the prototype solution must satisfy certain constraints. These constraints describe the important perceptual features of the sample shapes that the proposed prototype must retain. The contour prototype generated from a set of planar objects was used as an example of the approach, and the corners were used as the perceptual features to be preserved in the proposed prototype shape. However, finding a prototype solution for more than two contours is computationally intractable. A tree-based approach is therefore proposed in which an efficient greedy random algorithm is used to obtain a good approximation of the proposed prototype and analyze the expected complexity of the algorithm. The proposed prototype-generation process for hand-drawn patterns is described and discussed in this paper. 相似文献
13.
Plastic deformation in a multifunctional Ti-Nb-Ta-Zr-O alloy 总被引:7,自引:0,他引:7
S. Kuramoto T. Furuta J. H. Hwang K. Nishino T. Saito 《Metallurgical and Materials Transactions A》2006,37(3):657-662
Mechanisms for plastic deformation in the newly developed Ti-24 at. pct (Ta + Nb + V)-(Zr,Hf)-O alloys (Gum Metal) were investigated
in relation to their unique properties. Transmission electron microscopy revealed that the microstructure after deformation
was characterized by highly distorted crystal images, which are accompanied by numerous “giant faults.” Such plastic behavior
implies that a large amount of elastic stain energy was stored discretely and hierarchically during cold working. Calculated
elastic constants of the Ti-X (Nb,Ta,Mo,V) binary systems predicted that Young’s modulus in 〈001〉 and shear moduli along some
directions including slip systems in a bcc crystal were extraordinary small. The low modulus not only well explains the highly
distorted microstructure observed in the cold-worked specimens, but also signifies that ideal shear strength of the developed
alloys is a very small value, which is close to the practical strength required for plastic deformation in the alloy. This
implies that the giant faults observed in the deformed specimen were formed without the aid of dislocation glide. 相似文献
14.
We propose a new service for digital mobile communication systems. The service enables two or more users to hold a secure conference. Two requirements must be considered: privacy and authentication. Privacy involves ensuring that an eavesdropper cannot intercept the conversations of the parties holding the conference. Authentication involves ensuring that service is not obtained fraudulently in order to avoid usage charges. We present two new conference key distribution schemes for digital mobile communication systems. In these schemes, a group of users can generate a common secret keg over a public channel so that they may hold a secure conference 相似文献
15.
The paper addresses the design of two-level power system stabilizers using an optimal reduced order model whose state variables are torque angles and speeds. The reduced order model retains their physical meaning and is used to design a two-level linear feedback controller that takes into account the realities and constraints of electrical power systems. The two-level control strategy is used, and a global control signal is generated from the output variables to minimize the effect of interactions. The effectiveness of this controller is evaluated and a multimachine system is given as an example to illustrate the advantages of the proposed method. Responses of the system with a two-level scheme and an optimal reduced order scheme are included for comparative analysis. 相似文献
16.
Mathews V.K. Maddox R.L. Fazan P.C. Rosato J. Hwang H. Lee J. 《Electron Device Letters, IEEE》1992,13(12):648-650
Nitrided gate oxides offer several electrical and reliability advantages over conventional oxides and also provide a good barrier against impurity diffusion. Oxidation in nitrous oxide (N2O) has been very successful in overcoming some of the problems associated with nitridation in ammonia. The authors have observed that the extent of N2O oxidation has a strong detrimental effect on the drain leakage current of MOS transistors in the off state. This phenomenon has been identified to be caused by an increase in the active area junction leakage current 相似文献
17.
Hwang H.-K. Lee L.-S. Chen S.-H. 《Selected Areas in Communications, IEEE Journal on》1989,7(9):1450-1461
Multi-H phase-coded modulation (MHPM) is a bandwidth-efficient modulation scheme which offers substantial coding gain over conventional digital modulation schemes. MHPM with asymmetric modulation indices corresponding to the bipolar data +1 and -1 is considered, and numerical results for the minimum Euclidean distances are provided. It is shown that performance improvements on the error probability over conventional MHPM are gained with essentially the same bandwidth and a very slight modification in implementation. The upper bounds on the error probabilities as functions of observation intervals and received E b/N 0 are also investigated in detail. It is concluded that the concept of asymmetric modulation indices for MHPM is attractive for bandwidth and power-efficient modulation 相似文献
18.
Keon Woo Kang Jaemin Ann Hwang Soo Lee 《Electronics letters》1994,30(25):2153-2154
The authors propose a method to estimate the synchronisation offset for orthogonal frequency division multiplexing (OFDM) frame alignment without resort to pilot tones. A decision-directed maximum-likelihood estimation of frame synchronisation offset is derived, and the performance of the proposed scheme is confirmed by computer simulation for QAM systems 相似文献
19.
本文基于弹塑性分叉理论研究单向纤维增强复合材料的压缩破坏模式和压缩强度对缺陷的敏感性问题。对于常见复合材料,所得结论是:无缺陷或者小缺陷情况的破坏模式为倾斜破坏带;大缺陷情况的破坏模式为水平破坏带;形成水平破坏带的压力值小于形成倾斜破坏带的压力。 相似文献
20.
Design of two-level system stabilizers is considered using an optimal reduced-order model whose state variables are torque angles and speeds. The reduced-order model retains their physical meaning and is used to design a two-level linear feedback controller that takes into account the realities and constraints of the electrical power systems. The two-level control strategy is used, and a global control signal is generated from the output variables to minimize the effect of interaction. The effectiveness of this controller is evaluated, and an example, the multimachine system, is given to illustrate the advantages of the proposed method. The responses of the system with the two-level scheme and optimal reduced order scheme are included for comparative analyses 相似文献