共查询到20条相似文献，搜索用时 234 毫秒
1.
运用李亚普诺夫函数,设计所需状态反馈控制器,研究了具有分布时滞的中立型随机时滞系统的H∞控制,给出了H∞控制器存在的充分条件,使所得到的闭环系统均方渐近稳定,且满足所需要的H∞性能指标. 相似文献
2.
针对一类T-S模糊模型描述的非线性网络控制系统在数据丢包与执行器故障情况下的稳定性问题进行研究。首先,针对数据传输时的丢包现象,采用满足伯努利随机分布的随机变量加以表示,并采用Markov过程表示执行器随机故障现象;其次,基于分段二次Lyapunov函数,给出一个H∞静态输出反馈控制器设计的充分条件;接着采用Finsler引理分离条件中的耦合项,基于线性矩阵不等式,给出闭环系统满足H∞性能随机稳定的充分条件;最后通过数值算例验证提出的可靠分段H∞控制器设计方法的有效性与可行性。 相似文献
3.
利用随机截尾寿命试验数据,给出了两参数Pareto分布参数．可靠度和换效率的Bayes点估计及其置信限． 相似文献
4.
对于复合函数的求导法则，给出一种令人信服的严格的完整证明(其它教材中的证明均不完整或证明不能令人满意)；明确了∞-∞型的未定式定义，并给出了该未定式化为0／0型或∞／∞型的未定式的理论依据；利用两个推广定理证明了弱条件下不定积分的分部积分公式及变上限的定积分所确定的函数的奇偶性。 相似文献
5.
研究一类具有匹配不确定性,且状态及输出都有多时滞的广义系统的非脆弱鲁棒H∞控制．文中主要用LMI方法和积分不等式,获得系统的非脆弱鲁棒H∞控制器使闭环系统渐近稳定,且满足H∞性能的约束条件γ的时滞相关条件．给出具有加法不确定性控制器的设计方法． 相似文献
6.
利用随机截尾寿命试验数据,给出了两参数Pareto分布参数,可靠度和换效率的Bayes点估计及其置信限． 相似文献
7.
仝云旭 《商洛师范专科学校学报》2010,(2):22-27
讨论了一类不确定随机时滞系统的鲁棒L2-L∞降维滤波器设计问题。目的是设计一个比原系统维数低的确定维数的稳定线性滤波器,使得滤波误差动态系统是随机渐近稳定的且满足给定的L2-L∞性能要求γ。给出了解决这个问题的充分条件,并以参数显式化的形式给出了所求的鲁棒L2-L∞降维滤波器,所有这些结果都只利用了原始系统的矩阵而没有分解,这就使得设计过程简便,直接。 相似文献
8.
在定时截尾取损失函数为熵损失函数情形下,给出了瑞利分布参数θ的Bayes估计的一般形式,在给出先验分布的条件下得出了参数θ的Bayes估计的精确形式,最后证明了Bayes的可容许性． 相似文献
9.
谢先闻 《浙江教育学院学报》2006,(5):58-63
基于张量形式的Collins衍射积分公式，导出了维格纳分布函数（WDF）通过一般非轴对称系统的传输公式．结果表明，维格纳分布函数通过非轴对称系统的传输不改变形式，只要通过坐标变换就可以由系统输入面处的WDF求出输出面的WDF．给出了用系统的ABCD矩阵元表示的用于进行此坐标变换的表达式和等价的张量形式的WDF的坐标变换矩阵（WCTM）．这些结果在直角坐标中的表示式也被给出并被进一步地讨论．作为应用例，讨论了一个含柱透镜的系统． 相似文献
10.
讨论了一类不确定随机时滞系统的鲁棒L2-L∞降维滤波器设计问题。目的是设计一个比原系统维数低的确定维数的稳定线性滤波器,使得滤波误差动态系统是随机渐近稳定的且满足给定的L2-L∞性能要求γ。给出了解决这个问题的充分条件,并以参数显式化的形式给出了所求的鲁棒L2-L∞降维滤波器,所有这些结果都只利用了原始系统的矩阵而没有分解,这就使得设计过程简便,直接。 相似文献
11.
This paper deals with the statistical modeling of latent topic hierarchies in text corpora. The height of the topic tree is assumed as fixed, while the number of topics on each level as unknown a priori and to be inferred from data. Taking a nonparametric Bayesian approach to this problem, we propose a new probabilistic generative model based on the nested hierarchical Dirichlet process （nHDP） and present a Markov chain Monte Carlo sampling algorithm for the inference of the topic tree structure as well as the word distribution of each topic and topic distribution of each document. Our theoretical analysis and experiment results show that this model can produce a more compact hierarchical topic structure and captures more fine-grained topic relationships compared to the hierarchical latent Dirichlet allocation model. 相似文献
12.
烟草物流配送中心部门绩效评价是衡量烟草物流中心各部门业务实施效果,促进物流配送中心持续改进的重要手段。文章针对烟草物流配送中心绩效评价现有研究的不足,在已有的烟草行业标准的基础上,对烟草物流配送中心各部门的绩效评价体系进行构建,并引入三角模糊数概念,提出了基于Fuzzy-AHP的烟草物流配送中心部门绩效评价的评价模型。案例分析表明,该方法科学合理且操作性强。 相似文献
13.
A general procedure is proposed to estimate the reliability of a dual-span rotor based on nonparametric modeling on random uncertainty. First, the vibration equation of the rotor with random uncertainty is constructed based on random matrices through the nonparametric modeling approach. Second, the reliability estimation is then performed by response spectral analysis and the moment method. By making full use of the advantages of nonparametric method and response spectral analysis, not only is the requirement on probability density function (PDF) avoided, but also the first and second moments are no longer needed to be estimated or assumed for calculating the reliability. Finally, the statistical index Z*-value based on short-term predictability is introduced to investigate the influence of random uncertainties on the reliability of the dual-span rotor. Illustrating examples show that the results obtained from the proposed procedure are consistent with those from short-term predictability, such that dangerous ranges can be well identified during the start-up process of the rotor. 相似文献
14.
Inspection of differential item functioning (DIF) in translated test items can be informed by graphical comparisons of item response functions (IRFs) across translated forms. Due to the many forms of DIF that can emerge in such analyses, it is important to develop statistical tests that can confirm various characteristics of DIF when present. Traditional nonparametric tests of DIF (Mantel-Haenszel, SIBTEST) are not designed to test for the presence of nonuniform or local DIF, while common probability difference (P-DIF) tests (e.g., SIBTEST) do not optimize power in testing for uniform DIF, and thus may be less useful in the context of graphical DIF analyses. In this article, modifications of three alternative nonparametric statistical tests for DIF, Fisher's χ 2 test, Cochran's Z test, and Goodman's U test ( Marascuilo & Slaughter, 1981 ), are investigated for these purposes. A simulation study demonstrates the effectiveness of a regression correction procedure in improving the statistical performance of the tests when using an internal test score as the matching criterion. Simulation power and real data analyses demonstrate the unique information provided by these alternative methods compared to SIBTEST and Mantel-Haenszel in confirming various forms of DIF in translated tests. 相似文献
15.
对于县级土地利用规划管理信息系统设计,绝大多数人集中在系统功能上,忽视了系统作为"国家—省—地—县"四级访问结构的底层结点的性质和数据交换与共享的要求。在综合考虑系统构建的成本、功能需求、数据交换和共享、未来系统扩展等多种因素的基础上,基于ArcGIS Engine平台进行了系统设计。主要包括系统的目标和设计原则,系统总体结构设计,系统组网方案(即县级服务器端如何配置、客户端如何配置、县级国土部门与其上一级国土部门之间如何实现数据交换与共享),系统功能设计(即基本功能设计、规划管理功能设计和统计分析功能设计),基于Geodatabase的数据库设计和其他设计等。 相似文献
16.
This paper presents a distribution free method for predicting the extreme wind velocity from wind monitoring data at the site
of the Runyang Suspension Bridge (RSB), China using the maximum entropy theory. The maximum entropy theory is a rational approach
for choosing the most unbiased probability distribution from a small sample, which is consistent with available data and contains
a minimum of spurious information. In this paper, the theory is used for estimating a joint probability density function considering
the combined action of wind speed and direction based on statistical analysis of wind monitoring data at the site of the RSB.
The joint probability distribution model is further used to estimate the extreme wind velocity at the deck level of the RSB.
The results of the analysis reveal that the probability density function of the maximum entropy method achieves a result that
fits well with the monitoring data. Hypothesis testing shows that the distributions of the wind velocity data collected during
the past three years do not obey the Gumbel distribution. Finally, our comparison shows that the wind predictions of the maximum
entropy method are higher than that of the Gumbel distribution, but much lower than the design wind speed. 相似文献
17.
Daniel McNeish 《Journal of Experimental Education》2018,86(2):308-324
Some IRT models can be equivalently modeled in alternative frameworks such as logistic regression. Logistic regression can also model time-to-event data, which concerns the probability of an event occurring over time. Using the relation between time-to-event models and logistic regression and the relation between logistic regression and IRT, this article outlines how the nonparametric Kaplan-Meier estimator for time-to-event data can be applied to IRT data. Established Kaplan-Meier computational formulas are shown to aid in better approximating “parametric-type” item difficulty compared to methods from existing nonparametric methods, particularly for the less-well-defined scenario wherein the response function is monotonic but invariant item ordering is unreasonable. Limitations and the potential for Kaplan-Meier within differential item functioning are also discussed. 相似文献
18.
Many heuristic search methods exhibit a remarkable variability in the time required to solve some particular problem instances. Their cost distributions are often heavy-tailed. It has been demonstrated that, in most cases, rapid restart (RR) method can prominently suppress the heavy-tailed nature of the instances and improve computation efficiency. However, it is usually time-consuming to check whether an algorithm on a specific instance is heavy-tailed or not. Moreover, if the heavy-tailed distribution is confirmed and the RR method is relevant, an optimal RR threshold should be chosen to facilitate the RR mechanism. In this paper, an approximate approach is proposed to quickly check whether an algorithm on a specific instance is heavy-tailed or not. The method is realized by means of calculating the maximal Lyapunov exponent of its generic running trace. Then a statistical formula to estimate the optimal RR threshold is educed. The method is based on common nonparametric estimation, e.g. , Kernel estimation. Two heuristic methods are selected to verify our method. The experimental results are consistent with the theoretical consideration perfectly. 相似文献
19.
Under the assumption of strictly stationary process, this paper proposes a nonparametric model to test the kurtosis and conditional kurtosis for risk time series. We apply this method to the daily returns of S&P500 index and the Shanghai Composite Index, and simulate GARCH data for verifying the efficiency of the presented model. Our results indicate that the risk series distribution is heavily tailed, but the historical information can make its future distribution light-tailed. However the far future distribution's tails are little affected by the historical data. 相似文献
20.
研究了误差为AANA序列时非参数回归模型未知函数g（·）估计量的相合性问题,而AANA序列比NA序列要弱．在-般的条件下,利用C,不等式、Jensen不等式、AANA序列的极大值不等式以及权函数的-些性质,给出了非参数回归模型未知函数g（·）估计量的P-阶平均相合性和-致P-阶平均相合性,推广了相关文献已获得的部分结果． 相似文献