共查询到19条相似文献，搜索用时 187 毫秒
1.
采用Gröbner基方法,可以把一个在有限群作用下不变的多项式写成不变环的生成元的多项式.核心问题是如何有效地计算这个正维不变理想的Gröbner基.本文引入一个有效提升算法来计算这组Gröbner基.当用straight line program模型对整个计算过程进行复杂度分析时,可以把计算开销控制在多项式时间内. 相似文献
2.
在纽结理论上,为分辨不同的纽结,我们发现并研究了几种与纽结相关的不变量及多项式,如Alexander多项式△(t),Jones多项式V(t),Conway多项式V(t),Homfly多项式PL(1,m),BLM/Ho多项式Q(t),Kauffman多项式或F(a,z)等等.文章中主要探讨他们之间的关系,并由其中一个多项式推导出另外一种或几种多项式. 相似文献
3.
一、前言干燥作业失水量的计算,过去一直采用干基计算式。由于干基计算式是建立在干空气重量保持不变基础上的,而风机风量则是体积流量,风机输送的干空气重量随温湿度而变化,因而计算时需要进行换算。作者研究的湿基计算法,可以直接采用湿空气三要素(温度、相对湿度、体积流量)计 相似文献
4.
把K2(F2[C4×C4])的计算归结为计算截断多项式环F2C4[t]/(t4)的相对K2-群K2(F2C4[t]/(t4),(t)).运用Dennis-Stein符号及它们之间的关系进行细致的分析计算,给出了K2(F2[C4×C4])的一个极小生成元集并最终确定了K2(F2[C4×C4])=C34C92. 相似文献
5.
把K2(F2[C4×C4])的计算归结为计算截断多项式环F2C4[t]/(t4)的相对K2-群K2(F2C4[t]/(t4),(t)).运用Dennis-Stein符号及它们之间的关系进行细致的分析计算,给出了K2( F2[C4×C4])的一个极小生成元集并最终确定了K2(F2[C4×C4])=C34⊕C92. 相似文献
6.
7.
提出一种新的异构迁移学习方法.利用与目标数据集相关的异构特征数据集.通过把目标集和异构集的数据使用平移不变核(欧式距离核和径向基函数核),映射到一个新的再生核希尔伯特空间上.在新空间中2个数据集的特征相同,特征维度相等,分布接近,且保持数据的拓扑性质不变.实验证明,该方法特别是基于欧式距离核的方法取得了较好的效果,在目标训练集的标注数据较少时,有大于5%甚至超过10%的精度提高. 相似文献
8.
9.
研究了如下的拟线性椭圆型方程:△pu+uq+λup*-1=0,u∈W1o,p(Ω), (1λ)其中,Ω2是RN中具有光滑边界的有界区域,△pu=div( |▽u|p-2▽u),N≥3,2≤p＜N,0＜q＜1,p*=NP/N-P.设λ*(Ω,p,q)是拟线性椭圆型方程(1λ)可解的参数集的上确界.运用变分方法,在不要求具有对称性质的一般区域Ω上得到了λ*(Ω,p,q)的一个可以精确计算的下界. 相似文献
10.
在工程施工中经常会遇到软基地质,软基地质在建筑领域一直是个难题,备受建筑界的关注,通过软基处理水泥深层搅拌桩施工可以有效克服这一难题,我们所说的软基的概念就是将呈梅花桩型的水泥柱体支撑从而达到复合地基承载的效果,此文主要阐述在施工过程中如何能更有效的把控湿喷桩的成桩质量,从而确保软基达到预期的效果。 相似文献
11.
《Journal of The Franklin Institute》2019,356(8):4622-4647
The Region of Attraction of an equilibrium point is the set of initial conditions whose trajectories converge to it asymptotically. This article, building on a recent work on positively invariant sets, deals with inner estimates of the ROA of polynomial nonlinear dynamics. The problem is solved numerically by means of Sum Of Squares relaxations, which allow set containment conditions to be enforced. Numerical issues related to the ensuing optimization are discussed and strategies to tackle them are proposed. These range from the adoption of different iterative methods to the reduction of the polynomial variables involved in the optimization. The main contribution of the work is an algorithm to perform the ROA calculation for systems subject to modeling uncertainties, and its applicability is showcased with two case studies of increasing complexity. Results, for both nominal and uncertain systems, are compared with a standard algorithm from the literature based on Lyapunov function level sets. They confirm the advantages in adopting the invariant sets approach, and show that as the size of the system and the number of uncertainty increase, the proposed heuristics ameliorate the commented numerical issues. 相似文献
12.
Ｈａｍｍｅｒｓｔｅｉｎ模型基于神经网络的预测控制方法 总被引：1，自引：0，他引：1
Ｈａｍｍｅｒｓｔｅｉｎ模型是化工过程中最常用的模型之一,它由非线性静态环节和线性动态环节串连 组成,适合描述ｐＨ过程和具有幂函数、死区、开关等非线性特性的过程．这类模型的控制问题可以分解 为：线性模型的控制问题和非线性模型的求根问题．针对Ｈａｍｍｅｒｓｔｅｉｎ模型提出了一种基于神经网络的 模型预测控制策略,采用一组神经网络拟合非线性部分的逆映射．这种方法不需要假设Ｈａｍｍｅｒｓｔｅｉｎ模 型的非线性部分由多项式构成,并且避免已有研究在无根和重根情况下存在的问题．最后通过仿真试验证明了以上结论． 相似文献
13.
A method is presented in this paper to obtain an element of a transformation group, which takes a state space representation of a linear multivariable system to its semi-canonical Morse's form. The system under consideration is supposed to be right invertible, controllable and with no invariant zeros. The element of the transformation group involves state feedback, permutation of outputs and change of basis in states and inputs. 相似文献
14.
This paper is devoted to the robust stabilization problem for a class of MJLSs with mode transition probabilities taken to be partly known, unknown, and unknown but with known bounds. To meet the needs of less conservative stabilization conditions, this paper proposes a valuable approach that (1) can express the conditions in terms of matrix inequalities with homogeneous polynomial dependence on partly unknown transition probabilities and (2) can include all possible slack variables related to transition probability constraints in the relaxation process coupled with deriving a finite set of linear matrix inequalities (LMIs). Finally, two numerical examples are reported to illustrate the effectiveness of the derived stabilization conditions. 相似文献
15.
In this paper, a numerical method based on polynomial approximation, using Hermite polynomial basis, to obtain the approximate solution of generalized pantograph equations with variable coefficients is presented. The technique we have used is an improved collocation method. Some numerical examples, which consist of initial conditions, are given to illustrate the reality and efficiency of the method. In addition, some numerical examples are presented to show the properties of the given method; the present method has been compared with other methods and the results are discussed. 相似文献
16.
近40年来烟台地区气温与降水量变化的关系研究 总被引：9，自引：0，他引：9
利用烟台地区1960～1999年的气象资料,分析了近40年来该区气温与降水量之间的关系.结果表明,从20世纪60年代至90年代,气温呈上升趋势,而全年、夏季、秋季降水量则随温度上升而减少,二者之间表现出显著线性相关.春季降水量与气温相关性不明显,二者不达显著水平.冬季降水量与冬季平均气温之间相关性显著,降水量随温度升高而增加,可用二次多项式回归方程量化表示.这样,该区气温状况如何,为预测未来降水趋势提供了信息,对合理利用本地气候资源具有实际意义. 相似文献
17.
This paper addresses tacit-to-explicit knowledge externalization, arguably the most critical, and yet problematic, phase of Nonaka's knowledge creation theory. Specifically, we propose and describe instance-based cognitive mapping (ICM), a unique externalization process that analyzes multiple decision instances using the inductive learning algorithms of artificial intelligence to generate a polynomial representation of the knowledge worker's mental model, explicitly relating how the knowledge worker implicitly selects and weighs key factors in making decisions within a specific problem domain. After reviewing current externalization techniques, we describe the characteristics, and evaluate the advantages, of the ICM process. An exploratory test of the process suggests that inductive learning algorithms, such as the group method of data handling, can be used to discover a reasonable polynomial estimate of a knowledge worker's tacit mental model. This estimate can then be compared with other explicit models and standards, updated with new information and knowledge, and internalized by all interested knowledge workers. 相似文献
18.
Hugo T.M. Kussaba João Y. Ishihara Leonardo R.A.X. Menezes 《Journal of The Franklin Institute》2019,356(6):3797-3810
This paper proposes a robust version of the unscented transform (UT) for one-dimensional random variables. It is assumed that the moments are not exactly known, but are known to lie in intervals. In this scenario, the moment matching equations are reformulated as a system of polynomial equations and inequalities, and it is proposed to use the Chebychev center of the solution set as a robust UT. This method yields a parametrized polynomial optimization problem, which in spite of being NP-Hard, can be relaxed by some algorithms that are proposed in this paper. 相似文献
19.
《Journal of The Franklin Institute》2023,360(7):5082-5091
In this article, an adaptive tracking control approach using Bernstein polynomial approximation is firstly proposed for an unknown nonlinear dynamic system. Bernstein polynomial approximation aims to compensate the unknown nonlinear dynamic function. However, if Bernstein theorem is directly used, the Bernstein polynomial's coefficients need to be derived from the system dynamic function. Nevertheless, the dynamic function is presumed to be unknown, hence the polynomial approximation still cannot be used for designing this control. In order to obtain the available function approximation, adaptive strategy is considered to estimate these coefficients. Finally, by learning from the classical adaptive algorithm, the undetermined coefficient problem is addressed, so that the valid tracking control is found for the unknown nonlinear dynamic system. According to Lyapunov stability analysis and simulation experiment, it is concluded that the new adaptive scheme can realize the control objective. 相似文献