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101.
非平衡状态下双原子分子振动态的分布 总被引:1,自引:0,他引:1
为尝试修正Hammerling假设,在仔细分析了非平衡状态下双原子分子振动态的分布特征的基础上,提出了新的分布近似函数.该近似分布函数能很好地体现非平衡状态下双原子分子振动态分布的主要特征,其在离解反应速率的理论计算中的应用也证明是成功的.同时还部分证明了Park的双温模型具有其理论基础. 相似文献
102.
梁久祯 《北京航空航天大学学报》2001,27(4):421-424
将模糊Zadeh算子的定义域作了扩充,并重新定义为模糊极大极小算子,使其满足交换律、结合律和零元律.在此基础上提出一种模糊极大极小算子型神经元网络模型,符合一般模糊算子型神经元网络的定义.与传统的Zadeh算子型模糊神经网络相比具有较强的映射能力.详细证明了用该模糊极大极小算子神经元网络可以计算与图灵机等价的部分递归函数,从而表明模糊极大极小算子神经元网络的计算能力等价于图灵机.将传统神经元M-P模型神经网络的图灵等价性推广到模糊神经元网络. 相似文献
103.
李海桐 《北华航天工业学院学报》2011,21(6):33-35
近年来,廊坊市城市公共治理取得了一定的成效,主要呈现以下特征:一是治理主体逐步多元化;二是部门联动逐步完善化;三是城市管理日渐开放化。面对新的形势实现城市发展由传统治理向公共治理转变必须重塑政府,增强政府治理能力;实现政府理念再造;重新定位政府角色;增强政府回应性;激发城市主体参与意识。 相似文献
104.
本文给出了一类新的广义凸函数-(F,α,ρ,θ)-b-凸函数,讨论了多目标分式规划(MFP)的三种对偶模型:Mond-Weir型对偶、Lagrange型对偶、Schaible型对偶,并基于(F,α,ρ,θ)-b-凸性证明了各自相应的弱、强对偶定理。 相似文献
105.
《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2020,65(8):2036-2051
Research on empirical or physical models of ionospheric parameters is one of the important topics in the field of space weather and communication support services. To improve the accuracy of predicting the monthly median ionospheric propagating factor at 3000 km of the F2 layer (identified as M(3000)F2) for high frequency radio wave propagation, a model based on modified orthogonal temporal–spatial functions is proposed. The proposed model has three new characteristics: (1) The solar activity parameters of sunspot number and the 10.7-cm solar radio flux are together introduced into temporal reconstruction. (2) Both the geomagnetic dip and its modified value are chosen as features of the geographical spatial variation for spatial reconstruction. (3) A series of harmonic functions are used to represent the M(3000)F2, which reflects seasonal and solar cycle variations. The proposed model is established by combining nonlinear regression for three characteristics with harmonic analysis by using vertical sounding data over East Asia. Statistical results reveal that M(3000)F2 calculated by the proposed model is consistent with the trend of the monthly median observations. The proposed model is better than the International Reference Ionosphere (IRI) model by comparison between predictions and observations of six station, which illustrates that the proposed model outperforms the IRI model over East Asia. The proposed method can be further expanded for potentially providing more accurate predictions for other ionospheric parameters on the global scale. 相似文献
106.
Dempster-Shafer evidence theory, also called the theory of belief function, is widely used for uncertainty modeling and reasoning. However, when the size and number of focal elements are large, the evidence combination will bring a high computational complexity. To address this issue, various methods have been proposed including the implementation of more efficient combination rules and the simplifications or approximations of Basic Belief Assignments (BBAs). In this paper, a novel principle for approximating a BBA into a simpler one is proposed, which is based on the degree of non-redundancy for focal elements. More non-redundant focal elements are kept in the approximation while more redundant focal elements in the original BBA are removed first. Three types of degree of non-redundancy are defined based on three different definitions of focal element distance, respectively. Two different implementations of this principle for BBA approximations are proposed including a batch and an iterative type. Examples, experiments, comparisons and related analyses are provided to validate proposed approximation approaches. 相似文献
107.
108.
In practical applications, pieces of evidence originated from different sources might be modeled by different uncertainty theories. To implement the evidence combination under the Dempster–Shafer evidence theory(DST) framework, transformations from the other type of uncertainty representation into the basic belief assignment are needed. a-Cut is an important approach to transforming a fuzzy membership function into a basic belief assignment, which provides a bridge between the fuzzy set theory and the DST. Some drawbacks of the traditional a-cut approach caused by its normalization step are pointed out in this paper. An improved a-cut approach is proposed, which can counteract the drawbacks of the traditional a-cut approach and has good properties. Illustrative examples, experiments and related analyses are provided to show the rationality of the improved a-cut approach. 相似文献
109.
110.
为了提高主燃油控制装置的可靠性,在设计方案中增加了泵转换单元和计量转换活门。泵转换单元连接燃油计量子系统和导叶作动子系统,计量转换活门连接主燃油电液伺服阀与热计量电液伺服阀,实现了泵源备份和计量控制备份功能。通过AMESim建立的主燃油控制装置的数学模型对两个新增备份转换装置及功能进行了性能仿真,重点分析了备份切换过程中压力、流量等参数的波动情况。仿真结果表明:泵备份切换和计量备份切换过程引起的燃油波动都能在较短时间内恢复,分别为0.3s和1s。主燃油控制装置在单泵源状态工作时,导叶作动子系统工作正常,对计量燃油子系统的影响极小。 相似文献