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1.
This paper studies the stability of linear continuous-time systems with time-varying delay by employing new Lyapunov–Krasovskii functionals. Based on the new Lyapunov–Krasovskii functionals, more relaxed stability criteria are obtained. Firstly, in order to coordinate with the use of the third-order Bessel-Legendre inequality, a proper quadratic functional is constructed. Secondly, two couples of integral terms {∫t?htsx(s)ds,∫stx(s)ds} and {∫t?hMsx(s)ds,∫st?htx(s)ds} are involved in the integral functionals ∫t?htt(·)ds and ∫t?hMt?ht(·)ds, respectively, so that the coupling information between them can be fully utilized. Finally, two commonly-used numerical examples are given to demonstrate the effectiveness of the proposed method.  相似文献   

2.
根据实验研究了超声波照射对原油的降粘作用。比较了在不同含水率吓，经超声处理后原油粘度的变化情况。得出了当含水率为50％时，经超声处理后，原油可以形成水包油乳状液，其粘度能大幅度降低，但乳状液不稳定。在原油中掺入表面活性剂后，形成的乳状液稳定性增强，但其粘度有所增大。  相似文献   

3.
Given any finite family of real d-by-d nonsingular matrices {S1,…,Sl}, by extending the well-known Li–Yorke chaos of a deterministic nonlinear dynamical system to a discrete-time linear inclusion or hybrid or switched system:
xn∈{Skxn?1;1≤k≤l},x0∈Rdandn≥1,
we study the chaotic dynamics of the state trajectory (xn(x0, σ))n ≥ 1 with initial state x0∈Rd, governed by a switching law σ:N→{1,…,l}. Two sufficient conditions are given so that for a “large” set of switching laws σ, there exhibits the scrambled dynamics as follows: for all x0,y0∈Rd,x0≠y0,
lim infn→+∞∥xn(x0,σ)?xn(y0,σ)∥=0andlim supn→+∞∥xn(x0,σ)?xn(y0,σ)∥=∞.
This implies that there coexist positive, zero and negative Lyapunov exponents and that the trajectories (xn(x0, σ))n ≥ 1 are extremely sensitive to the initial states x0∈Rd. We also show that a periodically stable linear inclusion system, which may be product unbounded, does not exhibit any such chaotic behavior. An explicit simple example shows the discontinuity of Lyapunov exponents with respect to the switching laws.  相似文献   

4.
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5.
The present work proposes a relaxed gradient based iterative (RGI) algorithm to find the solutions of coupled Sylvester matrix equations AX+YB=C,DX+YE=F. It is proved that the proposed iterative method can obtain the solutions of the coupled Sylvester matrix equations for any initial matrices X0 and Y0. Next the RGI algorithm is extended to the generalized coupled Sylvester matrix equations of the form Ai1X1Bi1+Ai2X2Bi2+?+AipXpBip=Ci,(i=1,2,…,p). Then, we compare their convergence rate and find RGI is faster than GI, which has maximum convergence rate, under an appropriative positive number ω and the same convergence factor µ1 and µ2. Finally, a numerical example is included to demonstrate that the introduced iterative algorithm is more efficient than the gradient based iterative (GI) algorithm of (Ding and Chen 2006) in speed, elapsed time and iterative steps.  相似文献   

6.
信息优势与投资者地缘效应的关系研究   总被引：1，自引：0，他引：1       下载免费PDF全文
李延喜  高锐  杜瑞 《科研管理》2012,33(2):115-121
投资者偏爱地理位置近的上市公司的现象被称为地缘效应,其成因一直是资本市场中的一个未解之谜。本文以上海、天津、大连的3710名投资者为研究样本,从信息优势角度解释了地缘效应。研究发现,中国资本市场内部存在地缘效应;信息优势与地缘效应之间存在倒U型关系,即当信息优势小于临界值时,地缘效应随着信息优势的增强而增强;当信息优势大于临界值时,地缘效应随着信息优势的增强而减弱。研究认为随着信息优势强度的增加,信息目标由少到多,信息涉及的上市公司由近及远,由此使得投资者投资的分散程度不断提高,这是信息优势与地缘效应之间呈现倒U型关系的主要原因。  相似文献   

7.
This paper discusses the problem of synchronization for delayed neural networks using sampled-data control. We introduce a new Lyapunov functional, called complete sampling-interval-dependent discontinuous Lyapunov functional, which can adequately capture sampling information on both intervals from r(t?τ¯) to r(tk?τ¯) and from r(t?τ¯) to r(tk+1?τ¯). Based on this Lyapunov functional and an improved integral inequality, less conservative conditions are derived to ensure the stability of the synchronization error system, leading to the fact that the drive neural network is synchronized with the response neural network. The desired sampled-data controller is designed in terms of solutions to linear matrix inequalities. A numerical example is provided to demonstrate that the proposed approaches are effective and superior to some existing ones in the literature.  相似文献   

8.
《Journal of The Franklin Institute》2022,359(17):10231-10266
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9.
控制机制对创业能力与突变创新关系影响研究   总被引：1，自引：0，他引：1  
郭海  李垣  段熠 《科研管理》2007,28(5):25-30
通过建立一个概念模型论证了企业家创业能力、控制机制与突变创新之间的关系,并采用多行业的大样本数据验证了我们的模型。分析结果表明在需求不确定阻碍企业创新的转型时期,企业家创业能力促进突变创新开展,这一关系进一步受到不同控制机制的调节影响。具体地,行为控制增强创业能力与突变创新间的正相关关系,而结果控制削弱两者间关系。这反映出控制机制在企业突变创新过程中担当的重要角色。  相似文献   

10.
气井一点法试井工艺技术简单,施工成本低,施工周期短,已广泛应用于大牛地气田气井产能预测和评价,一点法试井只要求测取稳定的地层压力、一个工作制度下的稳定流压,但一点法对资料的分析带有一定的经验性和统计性,分析误差较大。特别是大牛地气田属于低渗透气藏,压力恢复缓慢,所测的地层静压值偏低,求产开井3天以上多数井测取不到稳定的流压,所取流压值偏高,计算的无阻流量均偏高。因而根据一点法所得到的产能方程来预测地层产能往往偏大,经验统计表明,开井时间越长,所求的无阻流量越低。  相似文献   

11.
钟亮环  林彬  李强 《科教文汇》2014,(15):184-184
人才培养工作作为高校工作的中心,高校要从五方面落实人才培养的中心地位：一要思想重视,要充分认识到大学的根本任务是进行人才培养;二要知行合一,贯彻执行好人才培养质量是大学的生命线的忧患意识;三要抓住重点,不断提高师资队伍素质;四要健全机制,切实保障校领导深入研究教学;五要重视精神,营造良好校风、学风。  相似文献   

12.
试验以紫薯为主要原料,研究澄清型紫薯汁的加工工艺。通过正交试验及验证实验,确定澄清型紫薯汁生产的工艺为:紫薯干片制备工艺参数为薯片厚度3mm,干制温度80℃,干制时间7h;澄清型紫薯汁生产配方为白砂糖4%,葡萄糖3%,海藻糖3%,柠檬酸0.1%,羧甲基纤维素钠0.1/%,食盐0.05%,山梨酸钾0.03%,红薯香精0.01%,紫薯干片5%。  相似文献   

13.
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14.
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15.
Consider the continuous-time matrix Riccati operator Ricc(Q)=AQ+QA′?QSQ+R. In this work, we consider the robustness of this operator to direct perturbations of the matrices (A, R, S) and, in particular, the flow robustness of the corresponding Riccati differential equation. For a given class of perturbation, we show that the corresponding differential equation is well defined in the sense it is bounded above and below, it has a well-defined fixed point, and it converges to this fixed point exponentially fast. Moreover, the flow of the perturbed Riccati flow is close to the nominal Riccati flow when the perturbation is small; i.e. we prove a continuity-type condition in the size of the perturbation.  相似文献   

16.
Let {Πτ(m, n): m?≥?n?≥?0} be the family of periodic discrete transition matrices generated by bounded valued square matrices Λτ(n), where τ:[0,1,2,?)→Ω is an arbitrary switching signal. We prove that the family {Πτ(m, n): m?≥?n?≥?0} of bounded linear operator is uniformly exponentially stable if and only if the sequence n?∑k=0neiαkΠτ(n,k)w(k):Z+→R is bounded.  相似文献   

17.
技术创新与广义需求圆锥体   总被引：1，自引：0，他引：1  
贾文毓 《科学学研究》2007,25(1):165-167
廖什的需求圆锥体可以泛化为一种更加普适的广义需求圆锥体。这是一个大中涵小的多个圆锥体的集合体,与廖什的单一形态的需求圆锥体有别。广义需求圆锥体的大中生小的孕育是由技术创新导致的,亦即其不断的“胎生”是由技术创新推动的。在一定时段内,影响广义需求圆锥体体积大小的主要因子是交通条件,而交通的发达程度是与科技进步紧密关联的。  相似文献   

18.
A novel method of noise variance measurement in the presence of strong sine burst interference with unknown parameters is presented. The measurement system is based on the Adaptive Sine Pulse Shortener (ASPS) which shorts each sine pulse from which the interfering burst is composed. After this a conventional noise variance measurement method is applied. A measurement accuracy is satisfactory when the interfering signal is strong and the number of periods of interfering sine-wave in each sine pulse is great. While a practical implementation of the proposed procedure is not simple in hardware, the microprocessor implementation is quite realizable.  相似文献   

19.
桂华明  马士华 《科研管理》2012,33(9):95-106
本文考虑了JIT环境下基于Supply-hub的供货模式,建立了制造商、Supply-hub和供应商的平均成本函数,并提出了分别由制造商和供应商负责Supply-hub营运及成本的生产与订货批量模型。结果表明,在Supply-hub适用的条件下,相比由制造商负责,供应商负责Supply-hub的运营及成本时,对供应商有利而不利于制造商,但整个供应链的总成本减少,通过供应商与制造商之间的协商和利益转移,可以使制造商和供应商的成本都有所减少,从而实现整个供应链的Pareto优化,此外,供应商距离Supply-hub越远,相比制造商负责,由供应商负责Supply-hub的营运及成本对整个供应链更有利。  相似文献   

20.
研究了一个同频四通道旋转关节,一路高功率通道作为雷达和通道,一路低功率通达作为雷达差通道,另两路低功率通道作为雷达对消信号通道。设计了旋转关节的结构,分析了其主要参数的选取以及设计方法,并给出了测试结果,结果表明:其带宽可达到13%,电压驻波比均小于1.27,插入损耗小于0.63dB,设计结果满足相关要求。该旋转关节已用于研制的某型号雷达,实际使用效果良好。  相似文献   

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