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991.
Summary It is shown that in systems like large aggregates of biological molecules, population inversion of charge carriers, for example
as produced by photoexcitation processes, may have competitive advantage beyond critical levels of excitation to produce ordered
spatial structures (morphological transitions). In our analysis electromagnetic radiation transfers electrons from bonding
states into a continuum of itinerant antibonding states in ap-type doped sample. In this system, in which energy is pumped continuously by an external source, the interplay of collective
and dissipative processes can be responsible for the condensation of a self-organized spatially ordered structure. The study
we present here is carried out resorting to the powerful nonequilibrium statistical operator method, thus showing that it
can be provide a mechano-statistical formalism at the microscopic level for the treatment of Prigogine's synergetic dissipative
structures.
The authors of this paper have agreed to not receive the proofs for correction 相似文献
992.
Summary We define and develop a novel process, related to stochastic resonance, in which a particle experiences three forces: a constant
drift, a zero-mean white noise, and a time-periodic modulation. Upon reaching a threshold, the particle immediately returns
to the starting point. The resulting process exhibits multiple maxima in the output power at the modulation frequency as a
function of the white-noise variance, multimodal first-passage-time densities, and evidence of phase locking. Our model is
an extension of the Gerstein-Mandelbrot model of neuron firing to the case of periodic stimuli, and therefore has applications
in neural modeling.
Paper presented at the International Workshop ?Fluctuations in Physics and Biology: Stochastic Resonance, Signal Processing
and Related Phenomena?, Elba, 5–10 June 1994. 相似文献
993.
The interpretation of factors constitutes a major problem in factor analysis. Until now the underlying semantic aspects of the question have been studied only occasionally. However, there are some indications that the mechanical interpretation of the results may constitute in the immediate future a real need in the realm of very large problems. On the other hand, the semantic study of multivariate statistical methods is the only way to warrant the validity of the mechanization procedures and the means to identify their limits. 相似文献
994.
本文概述了国内外大型智能仪器维修工作的现场在线测试方法,介绍了各种主要新技术及方法的特点,谈了实际工作中的一些体会和看法,强调了在维修工作中采用新技术、新设备的重要性。 相似文献
995.
Stack filters are more general and robust nonlinear filters than median filter, which possess threshold decomposition and stacking properties. Stack filters can be carried out one step using optical parallel fuzzy logic technique instead of three steps in threshold decomposition. All window, width 3 stack filters but two trivial stack filters are expressed in unified expression with coefficiencies to choose desired stack filter, so they are realized by an optical approach, window 3×3 separable stack filters can be realized by cascading the window width 3 stack filters. Window width 5 stack filters can be realized using the same method. 相似文献
996.
基于开关信号理论的三值IZL单变贵电路设计 总被引:1,自引:1,他引:0
本文应用开关信号理论的基本思想,分别用开关变量及三值信号变量来描写IZL电路!}?地开关晶体管的开关状态与三值电流信号·联结这两类变量的!}J比较运算和接地运算则用于描写电路内部开关元件与信号的相互作用过程,从而引入了适用于IzL电路的接地电流开关理论.基于该理论,本文对几类重要的三值IzL单变量电路进行了设计,结果表明,借助该理论能获得较简单的电路设计. 相似文献
997.
Using the beam fanning effect in a BaTiO3 crystal, we propose two simple set-ups to perform the function of an optical image combiner and an optical AND gate respectively. The optical image combiner combines two mutually coherent as well as mutually incoherent patterns transmitted to it separately into a single coherent pattern. This set-up can also be used as an optical OR gate. For the AND gate, the two input signals may also be mutually coherent or incoherent. Experimental results showed the response time of these two devices to range from 0.01 second to 2.5 seconds. 相似文献
998.
本文探讨了逻辑、面向对象、多层并发等方法的融合,介绍了一个较规范、较通用的面向对象多层分布并行逻辑语言MDP-PROLOG++,论述了该语言面向对象设施和并发执行设施的设计.该语言不仅可在多层分布并行系统上实现,也可在小规模粗粒度的并行系统上实现. 相似文献
999.
George Voutsadakis 《Mathematical Logic Quarterly》2003,49(4):347-352
Equivalent deductive systems were introduced in [4] with the goal of treating 1‐deductive systems and algebraic 2‐deductive systems in a uniform way. Results of [3], appropriately translated and strengthened, show that two deductive systems over the same language type are equivalent if and only if their lattices of theories are isomorphic via an isomorphism that commutes with substitutions. Deductive equivalence of π‐institutions [14, 15] generalizes the notion of equivalence of deductive systems. In [15, Theorem 10.26] this criterion for the equivalence of deductive systems was generalized to a criterion for the deductive equivalence of term π‐institutions, forming a subclass of all π‐institutions that contains those π‐institutions directly corresponding to deductive systems. This criterion is generalized here to cover the case of arbitrary π‐institutions. 相似文献
1000.
Giangiacomo Gerla 《Mathematical Logic Quarterly》1994,40(3):357-380
Let S be a set, P(S) the class of all subsets of S and F(S) the class of all fuzzy subsets of S. In this paper an “extension principle” for closure operators and, in particular, for deduction systems is proposed and examined. Namely we propose a way to extend any closure operator J defined in P(S) into a fuzzy closure operator J* defined in F(S). This enables us to give the notion of canonical extension of a deduction system and to give interesting examples of fuzzy logics. In particular, the canonical extension of the classical propositional calculus is defined and it is showed its connection with possibility and necessity measures. Also, the canonical extension of first order logic enables us to extend some basic notions of programming logic, namely to define the fuzzy Herbrand models of a fuzzy program. Finally, we show that the extension principle enables us to obtain fuzzy logics related to fuzzy subalgebra theory and graded consequence relation theory. Mathematics Subject Classification : 03B52. 相似文献