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121.
Fuzzy reasoning Petri nets 总被引:2,自引:0,他引:2
Meimei Gao MengChu Zhou Xiaoguang Huang Zhiming Wu 《IEEE transactions on systems, man, and cybernetics. Part A, Systems and humans : a publication of the IEEE Systems, Man, and Cybernetics Society》2003,33(3):314-324
This paper presents a fuzzy reasoning Petri net (FRPN) model to represent a fuzzy production rule-based system. The issues of how to represent and reason about rules containing negative literals are addressed in the proposed PN model. The execution rules based on the model are defined formally using the operators in max-algebra. Then, a fuzzy reasoning algorithm is proposed to perform fuzzy reasoning automatically. The algorithm is consistent with the matrix equation expression method in the traditional PNs and allows one to exploit the maximum parallel reasoning potential embedded in the model. The legitimacy and feasibility of the proposed approach are proved and validated through a turbine fault diagnosis expert system. 相似文献
122.
Shyi-Ming Chen Chung-Ming Huang 《Fuzzy Systems, IEEE Transactions on》2003,11(4):495-506
In recent years, some methods have been proposed to estimate values in relational database systems. However, the estimated accuracy of the existing methods are not good enough. In this paper, we present a new method to generate weighted fuzzy rules from relational database systems for estimating values using genetic algorithms (GAs), where the attributes appearing in the antecedent part of generated fuzzy rules have different weights. After a predefined number of evolutions of the GA, the best chromosome contains the optimal weights of the attributes, and they can be translated into a set of rules to be used for estimating values. The proposed method can get a higher average estimated accuracy rate than the methods we presented in two previous papers. 相似文献
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125.
An algorithm is introduced which labels formants from the peaks of pole-focused spectra. A clustering procedure is first used to produce line segments of possible formants. These can be considered as anchor traces for the later processing. Rule-based labelling is then applied to provide final formant trace estimates. Experimental results show that the proposed algorithm offers improved formant labelling accuracy. 相似文献
126.
The two-dimensional finite-element method is applied to analyze the shrinkage and splitting of microcracks regularly arranged
on or perpendicular to a grain boundary under pressure. Grain-boundary and surface diffusions are coupled by the boundary
conditions at the triple point of the microcrack surface and the grain boundary. The shrinkage and splitting processes for
the two kinds of microcracks are revealed by detailed finite-element analyses. For the microcrack lying on a grain boundary,
it first shrinks to a small void shape, then the void is split by the grain boundary and the two split voids assume a cylindrical
shape under the capillary force of the surface. For the microcrack perpendicular to the grain boundary, it is split into two
segments by the grain boundary during the early stage of shrinkage. Then, the split microcracks stop shrinking and evolve
into two cylindrical channels with a circular section by the capillary force of the surface. These evolution processes are
controlled by the applied pressure, microcrack spacing, ratio of grain-boundary diffusion to surface diffusion, and equilibrium
dihedral angle, defined by surface and grain-boundary tensions. The influences of these controlled parameters on the evolution
processes are numerically clarified based on a great number of finite-element analyses. 相似文献
127.
A sol-gel process has been successfully utilized to produce hybrid materials incorporating polymeric/oligomeric components of polydimethyl siloxane(PDMS) with silicon glasses. All the samples made were transparent and flexible. Dynamic mechanical studies indicate that a portion of the siloxane species is phase-separated while the remainder is well dispersed. The effect of acid content were proven to be significant on the dispersion of the siloxane components and on the structure and properties of final products. 相似文献
128.
A production learning system (PLS) based on the tool model was constructed as a decision support and real-time information update system to forecast the cycle time. A tool model includes a waiting model and a processing model. Each of the waiting and processing models uses a backpropagation neural network to establish the relationship between the input and output (time) of the model. Hence, cycle time estimation, tool group move and confirm line item performance (CLIP) value can be obtained based on the memory stored in the neural network. The result shows that the forecasting ability of the PLS has an error rate below 8% on average 相似文献
129.
A novel directional-coupler optical switch based on the concept of the field-induced guide is demonstrated for the first time. The device exhibits a good switching characteristic between two output ends with a crosstalk of -10 dB at a 1.15 mu m wavelength for a device with an 800 mu m coupling length.<> 相似文献
130.
热释电系数的测量方法 总被引:2,自引:0,他引:2
描述热释电系数的两种测量方法。其一为电荷积分法,测试系统简单,测量数据准确,且能满足零电场条件下的测量。其二为动态电流法,采用调制热源技术,研究在特定温度条件下热释电材料的动态热释电响应。 相似文献