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41.
基于粗糙集理论的知识约简及应用实例 总被引:5,自引:0,他引:5
在保持分类能力不变的前提下 ,通过利用粗糙集理论中的知识约简方法 ,在保护知识库分类不变的条件下 ,删除其中不相关或不重要的知识 ,从而导出问题的决策 .利用基于决策表的粗糙集模型算法 ,实例分析如何数字化表示决策表 ,并对其进行属性约简和属性值的约简 ,从而提取决策规则 . 相似文献
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Changes in thin zinc-sulfide films under the action of the γ-radiation of Co60 are studied by investigating electroluminescence spectra of terbium embedded in these films as a luminescent probe. It is
shown that changes in the relation of the intensities of bands, a decrease in their halfwidth and the background component,
and simplification of the spectrum are observed in a short-wave region of the Tb radiation spectrum that corresponds to5D3→7Fj transitions. The same modification of the radiation spectrum is characteristic of ZnS films whose crystalline structure is
ordered in the course of thermal annealing at a temperature of 350°C. Based on the analysis of the data obtained it is inferred
that irradiating the ZnS films with small radiation doses of 104–105 rad leads to the ordering of their crystalline structure due to the elimination of one of the types of structural defects.
Institute of Physics of Semiconductors, National Academy of Sciences of Ukraine, 45, Nauka Ave., Kiev-28, 252650. Translated
from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 3, pp. 338–341, May–June, 1997. 相似文献
46.
A. P. Prishivalko 《Journal of Applied Spectroscopy》1997,64(1):94-100
A method for finding the optimum sizes of pigment particles, their volume concentration, and the paint coating thickness that
provide the covering power and the required coloristic characteristics of reflected light for the minimum flow rate of pigments
is based on using a four-flow approximation of the solution to the equation of radiation transfer in dispersion media and
is extended to coatings of complex composition. The capabilities of the method are demonstrated by examples of coatings of
mixtures of hematite and rutile particles in a binder with n=1.5 for variations of the modal size and the half-width of the
size distribution of the pigment particles.
B. I. Stepanov Institute of Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated
from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 90–96, January–February, 1997. 相似文献
47.
本文研究将MCS-51型单片机用于普通数控机床,通过监控程序设计,进一步完善机床性能,使该系统具有显示功能,快速点动、自动四零、自动升降频率、自动换刀、自动齿隙补偿、刀具磨损补偿,暂停等多种功能. 相似文献
48.
本文简要介绍了计算机多媒体技术的发展及其主要产品;介绍了《维哈柯汉英多媒体触摸咨询系统制作工具平台PMJL》的开发过程和主要功能;应用该平台研制了《维哈柯汉英多文种多媒体触摸咨询系统》,并结合其制作过程介绍了各种多媒体资源在应用系统中的逻辑关系、组织处理及合成等方法. 相似文献
49.
A highly sensitive method for infrared radiation detection based on thermal resonance in an active bolometer is set forth. An active bolometer is a self-oscillating system consisting of an IR-sensitive cell in a feedback circuit of an adjustable proportional controller. The analysis of an active bolometer autonomous (dark) dynamics reveals that with a generalized gain factor A variation the system evolves from relaxation type towards oscillating and self-oscillating type. When A=Ac, where Ac is a critical value of the generalized gain factor A, the steady state loses stability through self-excited thermal oscillations. The resonance in a system weakly perturbed by IR radiation modulated at self-oscillation frequency q0[1+exp(iωct)] is considered. It is shown that in a small precritical vicinity =(A−Ac)/Ac of the gain factor the amplitude of forced thermal oscillations is proportional to q0/Ac. The D* calculation reveals that the detection power of a passive (A=0) bolometer increases with feedback introduction by a factor of 1/||. The detection powers of feasible versions of an active bolometer are compared. 相似文献
50.
Benjamin S. Hsiao Rong-Ming Ho Stephen Z. D. Cheng 《Journal of Polymer Science.Polymer Physics》1995,33(17):2439-2447
Unique crystallization and melting behavior in poly(aryl ether ketone ketone) containing alternated terephthalic and isophthalic moieties were studied by time-resolved synchrotron x-ray methods. Recently, this material has been shown to exhibit three polymorphs (forms I, II, and III). In this work, we further investigated their distinctive thermal properties and found that form I is the dominating and the most thermally stable phase while form II is favored by fast nucleation conditions and is the least stable phase. On the other hand, form III represents a minor intermediate phase that usually coexists with form I and can be transferred from form II and to form I. Structural and morphological changes in form I have been followed by simultaneous wide-angle x-ray diffraction (WAXD)/small-angle x-ray scattering (SAXS) measurements during cold- or melt-crystallization and subsequent melting. In all cases, a larger dimensional change was found in the crystallographic a-axis than the b-axis during heating and cooling. This may be due to the greater lateral stress variation with respect to temperature along the a direction of the primary lamellae which is induced by either the formation of secondary lamellae or the preferential chain-folding direction in poly(aryl ether ketone ketone)s. During the phase transitions of form II ← III in the cold-crystallized specimen and form III ← I in the melt-crystallized samples, lamellar variables (long period, lamellar thickness, and invariant) obtained from SAXS remain almost constant. This indicates that the density distribution in the long spacing is independent of the melting in form II or III. For melt-crystallization, the corresponding changes in unit-cell dimensions and lamellar morphology during the annealing-induced low endotherm are most consistent with the argument that these changes are due to the melting of thin lamellar population. © 1995 John Wiley & Sons, Inc. 相似文献