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对覆盖广义Rough集中的隶属关系、隶属函数进行了定义,并利用隶属函数定义了集合的Rough包含与Rough相等,得到一些与Pawlak的Rough集不同的性质。 相似文献
3.
近些年来,许多处理近似问题的方法陆续被提出,其中利用Rough集理论计算两个集合的并和交的Rough隶属函数方法是被用较多的一种方法,但毕竟该方法精度较差。为此,介绍了一种精度较高的计算两个集合的并和交的Rough隶属函数方法,它克服了前者利用Rough集理论计算Rough隶属函数的复杂性,而迎来了简单和高精度的特点。 相似文献
4.
Huan Qing 《Entropy (Basel, Switzerland)》2022,24(8)
In network analysis, developing a unified theoretical framework that can compare methods under different models is an interesting problem. This paper proposes a partial solution to this problem. We summarize the idea of using a separation condition for a standard network and sharp threshold of the Erdös–Rényi random graph to study consistent estimation, and compare theoretical error rates and requirements on the network sparsity of spectral methods under models that can degenerate to a stochastic block model as a four-step criterion SCSTC. Using SCSTC, we find some inconsistent phenomena on separation condition and sharp threshold in community detection. In particular, we find that the original theoretical results of the SPACL algorithm introduced to estimate network memberships under the mixed membership stochastic blockmodel are sub-optimal. To find the formation mechanism of inconsistencies, we re-establish the theoretical convergence rate of this algorithm by applying recent techniques on row-wise eigenvector deviation. The results are further extended to the degree-corrected mixed membership model. By comparison, our results enjoy smaller error rates, lesser dependence on the number of communities, weaker requirements on network sparsity, and so forth. The separation condition and sharp threshold obtained from our theoretical results match the classical results, so the usefulness of this criterion on studying consistent estimation is guaranteed. Numerical results for computer-generated networks support our finding that spectral methods considered in this paper achieve the threshold of separation condition. 相似文献
5.
César R. García-Jacas Yovani Marrero-Ponce Ricardo Vivas-Reyes José Suárez-Lezcano Felix Martinez-Rios Julio E. Terán Longendri Aguilera-Mendoza 《Journal of computational chemistry》2020,41(12):1209-1227
Advances to the distributed, multi-core and fully cross-platform QuBiLS-MIDAS software v2.0 ( http://tomocomd.com/qubils-midas ) are reported in this article since the v1.0 release. The QuBiLS-MIDAS software is the only one that computes atom-pair and alignment-free geometrical MDs (3D-MDs) from several distance metrics other than the Euclidean distance, as well as alignment-free 3D-MDs that codify structural information regarding the relations among three and four atoms of a molecule. The most recent features added to the QuBiLS-MIDAS software v2.0 are related (a) to the calculation of atomic weightings from indices based on the vertex-degree invariant (e.g., Alikhanidi index); (b) to consider central chirality during the molecular encoding; (c) to use measures based on clustering methods and statistical functions to codify structural information among more than two atoms; (d) to the use of a novel method based on fuzzy membership functions to spherically truncate inter-atomic relations; and (e) to the use of weighted and fuzzy aggregation operators to compute global 3D-MDs according to the importance and/or interrelation of the atoms of a molecule during the molecular encoding. Moreover, a novel module to compute QuBiLS-MIDAS 3D-MDs from their headings was also developed. This module can be used either by the graphical user interface or by means of the software library. By using the library, both the predictive models built with the QuBiLS-MIDAS 3D-MDs and the QuBiLS-MIDAS 3D-MDs calculation can be embedded in other tools. A set of predefined QuBiLS-MIDAS 3D-MDs with high information content and low redundancy on a set comprised of 20,469 compounds is also provided to be employed in further cheminformatics tasks. This set of predefined 3D-MDs evidenced better performance than all the universe of Dragon (v5.5) and PaDEL 0D-to-3D MDs in variability studies, whereas a linear independence study proved that these QuBiLS-MIDAS 3D-MDs codify chemical information orthogonal to the Dragon 0D-to-3D MDs. This set of predefined 3D-MDs would be periodically updated as long as new results be achieved. In general, this report highlights our continued efforts to provide a better tool for a most suitable characterization of compounds, and in this way, to contribute to obtaining better outcomes in future applications. 相似文献
6.
M. V. Volkov 《Algebra Universalis》2001,46(1-2):97-103
No Abstract.
Received January 2, 2000; accepted in final form August 28, 2000. 相似文献
7.
《International Journal of Approximate Reasoning》2014,55(6):1357-1368
In literature, exact inversion methods for TSK fuzzy systems exist only for the systems with singleton consequents. These methods have binding limitations such as strong triangular partitioning, monotonic rule bases and/or invertibility check. These extra limitations lessen the modeling capabilities of the TSK fuzzy systems. In this study, an exact analytical inversion method for TSK fuzzy systems with singleton and linear consequents is presented. The only limitation of the proposed method is that the inversion variable should be represented by piecewise linear membership functions (PWL-MFs). In this case, the universe of discourse of the inversion variable is divided into specific regions in which only one linear piece exists for each PWL-MF at most. In the proposed method, the analytical formulation of TSK fuzzy system is expressed in terms of the inversion variable by using linear equations of PWL-MFs. Thus, the fuzzy system output in any region can be obtained by using the appropriate parameters of the linear equations of PWL-MFs defined within the related region. This expression provides a way to obtain linear and quadratic equations in terms of the inversion variable for TSK fuzzy systems with singleton and linear consequents, respectively. So, it becomes very easy to find exact inverse solutions for each region by using explicit analytical solutions for linear or quadratic equations. The proposed inversion method has been illustrated through simulation examples. 相似文献
8.
针对固体火箭发动机环境载荷的诸多不确定性,提出了环境载荷FHW量化评估算法.对比分析了火箭发动机的典型环境条件及其影响,采用熵值法确定了指标权重,基于FHW方法建立了火箭发动机的环境载荷评估模型,根据环境因素的分布特征给出评估指标的隶属函数,并获取其相应的灰色关联系数.算例验证了不同环境载荷因素对火箭发动机的影响程度,结果表明FHW评估策略和算法简单易行、精度高,在装备环境载荷量化评估中具有参考和应用价值. 相似文献
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10.
以某低渗透油藏为对象,首先在数据挖掘的基础上制定了低渗透油藏注CO_2驱筛选标准.基于模糊综合评价法,建立了适用于低渗透油藏CO_2驱适宜度评价的模糊综合评价模型,并运用该模型对目标油藏注CO_2的适宜度进行了评价.计算结果表明目标油藏注气驱开发适应性较好.评价过程有效地降低了直接进行注气开发的风险,为之后低渗透油藏注气开发提供了技术和经济上的指导. 相似文献