共查询到20条相似文献，搜索用时 26 毫秒
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《Journal of The Franklin Institute》2023,360(3):1706-1732
One of the drawbacks of the controllability theory for nonlinear systems is that most existing controllability criteria are not algebraically verifiable, which makes them difficult to apply especially if the system dimension is high. Thus, it is a significant task to seek algebraically verifiable controllability criteria for nonlinear systems. In this paper, we study controllability of discrete-time inhomogeneous bilinear systems. In the classical results on controllability of such systems, a necessary condition is that the linear part has to be controllable. However, we will show that this condition is in fact not necessary for controllability. Specifically, we first define the spectrum for discrete-time inhomogeneous bilinear systems and reveal that the spectrum is a fundamental property which is very useful in investigating the controllability problems. We then present controllability criteria for the systems with real spectrum, which are algebraically verifiable. Furthermore, we also provide algorithms for the controllable systems to compute the exact or approximated control inputs to achieve the transition between any given pair of states. The presented controllability criteria and algorithms work for the systems in any finite dimension and are easy to implement. More importantly, through our controllability criteria, we reveal that controllability of the linear part is not necessary for discrete-time inhomogeneous bilinear systems to be controllable. Examples are given to illustrate the presented algebraic controllability criteria. 相似文献
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针对高新技术企业知识产权能力测度问题的指标关联性、定性定量相结合性以及总量指标与相对指标兼顾性，本文首先设计了研究方案，包括内涵界定、测度指标体系构建以及基于DEMATEL-VIKOR的指数模型设计；然后，以2013年~2015年615家样本企业的知识产权采集信息为基础进行了实证研究。研究表明：①测度结果有助于企业管理者洞悉自身知识产权能力的真实水平及年度发展态势、明晰优势和短板以及与同行的差距；②决策机制的选择对高新技术企业知识产权能力测度结果具有显著影响，由此验证了所给模型的有效性。 相似文献
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In this paper, the stability problem of discrete-time systems with time-varying delay is considered. Some new stability criteria are derived by using a switching technique. Compared with the Lyapunov–Krasovskii functional (LKF) approach, the method used in this paper has two features. First, a switched model, which is equivalent to the original system and contains more delay information, is introduced. It means that the criteria obtained by using the LKF method can be regarded as stability criteria for the switched system under arbitrary switching. Second, when the switching signal is known, the stability problem for the switched model under constrained switching is considered and piecewise LKFs are adopted to obtain stability criteria. Since constrained switching is less conservative than arbitrary switching if the switching signal is known, one can know that the obtained results in this paper are less conservative than some existing ones. Two examples are given to illustrate the effectiveness of the obtained results. 相似文献
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针对初学者对线性规划问题解的判定准则的困惑,本文用实例阐明了如何判定线性规划问题的求解结果。教学实践证明例析方法更能够加深学生对线性规划问题解的认识和理解。 相似文献
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The asymptotic stability of linear neutral systems with a single delay is investigated in this article. Based on the characteristic equation, new algebraic criteria for the stability of the system are derived in terms of the spectral radius of corresponding modulus matrices. The significance of our new criteria is that it takes into consideration the structure information of the system matrices, thus reducing the conservatism found in the literature. Numerical examples are given to demonstrate the new stability criteria and to compare them with the previous results in the literature. 相似文献
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Taotao Hu Zheng He Xiaojun Zhang Shouming Zhong Xueqi Yao 《Journal of The Franklin Institute》2021,358(7):3847-3867
In this paper, the problem of delay-dependent stability analysis of fractional-order systems with time-varying delay is investigated. First, a class of novel fractional-order integral inequalities for quadratic functions by constructing appropriate auxiliary functions is proposed, which has been proven to be useful in analyzing fractional-order systems with time-varying delay. Based on these proposed inequalities, the Lyapunov–Krasovskii functions are designed to deal with the time-varying delay terms, reducing the conservatism of the stability criteria. Furthermore, delay-dependent criteria are derived to achieve asymptotic stability of fractional-order systems with time-varying delay. Finally, two examples are provided to illustrate the effectiveness and feasibility of the proposed stability criteria. 相似文献
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This paper is concerned with the stability analysis of time-delay systems. Lyapunov–Krasovskii functional method is utilized to obtain stability criteria in the form of linear matrix inequalities. The main purpose is to obtain less conservative stability criteria by reducing the estimation gap of the time derivative of the constructed Lyapunov–Krasovskii functional. First, a generalized multiple-integral inequality is put forward based on Schur complement lemma. Then, some special cases of the proposed generalized multiple-integral inequality are given to estimate single and double integral terms in the derivative of Lyapunov–Krasovskii functional. Furthermore, less conservative stability criteria are derived. Finally, three examples are given to illustrate the improvement of the proposed criteria. 相似文献
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Xinli Yin Bailong Yang Jianxiang Xi Xiaojun Yang 《Journal of The Franklin Institute》2019,356(7):4061-4075
The current paper addresses leader-following guaranteed cost synchronization with the cost budget given previously for the second-order wireless sensor networks. The published researches on guaranteed cost synchronization design criteria usually are based on the linear matrix inequality (LMI) techniques and cannot take the cost budget given previously into consideration. Firstly, the current paper proposes a guaranteed cost synchronization protocol, which can realize the tradeoff design between the battery power consumption and the synchronization regulation performance. Secondly, for the case without the given cost budget, sufficient conditions for leader-following guaranteed cost synchronization are presented and an upper bound of the cost function is shown. Thirdly, for the case that the cost budget is given previously, the criterion for leader-following guaranteed cost synchronization is proposed. Especially, the value ranges of control gains in these criteria are determined, which means that the existence of control gains in synchronization criteria can be guaranteed, but the LMI techniques can only determine the gain matrix and cannot give the value ranges of control gains. Moreover, these criteria are only associated with the minimum nonzero eigenvalue and the maximum eigenvalue, which can ensure the scalability of the wireless sensor networks. Finally, numerical simulations are given to illustrate theoretical results. 相似文献
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国家就哪些技术应重点发展,哪些技术应限制发展作出正确决策,对于合理利用有限资源是至关重要的.本文基于对影响战略层次上的技术优先级的4个要素的分析,提出一种数学方法,可以有效地解决技术优先级的确定问题.本文采取的4个要素的度量方法,实质上是从定性思维向定量评估的合理转化.本方法既实用,又便于操作. 相似文献
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This paper is concerned with the stability and stabilization for systems with two additive time-varying input delays arising from networked control systems. A new Lyapunov functional is constructed and a tighter upper bound of the derivative of the Lyapunov functional is derived by applying a convex polyhedron method. The resulting stability criteria are of fewer matrix variables and less conservative than some existing ones. Based on the stability criteria, a state feedback controller is designed such that the closed-loop system is asymptotically stable. Numerical examples are given to show the less conservatism of the stability criteria and the effectiveness of the designed method. 相似文献
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耕地分等中土壤质量指标体系与分等方法 总被引：51，自引：3，他引：51
土壤质量指标是耕地分等指标的重要组成部分。耕地分等中土壤指标的选择应该遵循稳定性、空间变异性、主导性、生产性原则。主成分分析、相关分析、土壤特性响应时间、变异系数等方法是选取耕地分等指标的科学定量方法 ,但最有效的耕地分等指标体系选取方法应根据土壤学研究成果和生产实践经验。而指数和方法是综合评价耕地等级的有效方法。 相似文献
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PIO是飞行仿真软件分析的最重要的内容之一。飞行员诱发振荡（PIO）是一种人-机闭环系统的不稳定的动态运动,通常由飞行员试图执行精确的飞行操纵任务所致。目前,已经研发出了大量的PIO理论用于预测PIO的敏感性,本研究仅对3个PIO准则进行理论研究和预测命中率分析,即带宽/俯仰速率超调准则、Smith-Geddes准则和Gibson相位速率准则。 相似文献
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The problem of asymptotic stability of linear neutral systems with multiple delays is addressed in this article. Using the characteristic equation approach, new delay-independent stability criteria are derived in terms of the spectral radius of modulus matrices. The structure information of the system matrices are taken into consideration in the proposed stability criteria, thus the conservatism found in the literature can be significantly reduced. Simple examples are given to demonstrate the validity of the criteria proposed and to compare them with the existing ones. 相似文献
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本文首先从科学学的角度,提出了基础学科发展的衡量标准;然后,依据这些标准,从投入和产出两方面对我国十大基础学科的基础性研究状况进行多指标系统分析与估价。并得出了若干有意义的结论。 相似文献
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心理健康的标准是心理健康领域中一个基本的理论问题。近来,关于这方面的研究很多,各领域的专家提出了很多种标准,但是一直存在争议,也没有形成统一的标准。本文根据国内学者提出的标准,试着阐述心理健康标准研究中可能存在的问题、研究趋势,并在此基础上,提出一些建议。 相似文献
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Qing Wang Jin-Liang Wang Yan-Li Huang Shun-Yan Ren 《Journal of The Franklin Institute》2018,355(14):6597-6616
The generalized lag synchronization of multiple weighted complex dynamical networks with fixed and adaptive couplings is investigated in this paper, respectively. By designing appropriate controller, several synchronization criteria are presented for multiple weighted complex dynamical networks with and without time delay based on the selected Lyapunov functional and inequality techniques. Moreover, an adaptive scheme to update the coupling weights is also developed for ensuring the generalized lag synchronization of multiple weighted complex dynamical networks with and without time delay. Finally, two numerical examples are provided in order to validate effectiveness of the proposed generalized lag synchronization criteria. 相似文献
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Arthur Taylor Author Vitae 《Information processing & management》2012,48(1):136-153
Relevance judgments occur within an information search process, where time, context and situation can impact the judgments. The determination of relevance is dependent on a number of factors and variables which include the criteria used to determine relevance. The relevance judgment process and the criteria used to make those judgments are manifestations of the cognitive changes which occur during the information search process.Understanding why these relevance criteria choices are made, and how they vary over the information search process can provide important information about the dynamic relevance judgment process. This information can be used to guide the development of more adaptive information retrieval systems which respond to the cognitive changes of users during the information search process.The research data analyzed here was collected in two separate studies which examined a subject’s relevance judgment over an information search process. Statistical analysis was used to examine these results and determine if there were relationships between criteria selections, relevance judgments, and the subject’s progression through the information search process. Findings confirm and extend findings of previous studies, providing strong statistical evidence of an association between the information search process and the choices of relevance criteria by users, and identifying specific changes in the user preferences for specific criteria over the course of the information search process. 相似文献