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1.
企业创新发展已成为企业可持续发展的关键,是国家经济发展的重要助推器。企业创新研发过程会出现知识溢出行为,而知识溢出行为一方面将打击创新企业的创新积极性,但另一方面会促进企业与其他合作成员的合作关系。从知识传播过程入手,运用信息粘滞性去控制知识溢出程度,根据企业创新进程构建企业创新策略演化模型。研究发现独立创新阶段,采取知识投入策略的企业短期内会通过增加信息粘滞性来避免知识溢出,当企业双方都进行知识投入时,合作逐渐向协同创新发展;协同创新阶段,企业双方同时采用知识投入策略时,知识转移促进企业形成“溢出-吸收-反吸收”合作回路,知识内化能力、知识投入水平与政府补贴正向激励合作,信息粘滞性影响被合作优势消除。  相似文献   

2.
A discrete model for computer simulations of the clustering dynamics of social amoebae is presented. This model incorporates the wavelike propagation of extracellular signaling of 3′–5′‐cyclic adenosine monophosphate (cAMP), the sporadic firing of cells at early stage of aggregation, the signal relaying as a response to stimulus, and the inertia and purposeful random walk of the cell movement. It is found that the sporadic firing below the threshold of cAMP concentration plays an important role because it allows time for the cells to form synchronous firing right before the stage of aggregation, and the synchronous firing is critical for the onset of clustering behavior of social amoebae. A Monte‐Carlo simulation was also run which showed the existence of potential equilibriums of mean and variance of aggregation time. The simulation result of this model could well reproduce many phenomena observed by actual experiments. © 2013 Wiley Periodicals, Inc. Complexity 20: 16–26, 2014  相似文献   

3.
Sequences of intervals between firing times (interspike interval (ISI)) from a pair of locus ceruleus (LC) neurons coupled by axon–dendrite synapse with stimulus of constant and chaos are investigated in this paper. We analyze how the dynamical properties of chaotic input determine those of the output ISI sequences, and assess how various strength of stimulus and coupling affects the input–output relationship. The attractors constructed from delay embeddings of ISIs and of chaotic input are compared from the points of view of geometry and nonlinear dynamics characteristics, i.e., Lyapunov exponent spectrum (LES), Kaplan–York fractal dimension (KYD) and unstable periodic orbit (UPO). For the coupled LC neurons system investigated, with the moderate strength of stimulus and coupling, the synchronous oscillation of the two neurons is well preserved even if the external stimulus is chaotic; the similarity between these attractors is high only when the afferent stimulus strength is smaller and rate is lower. When these conditions are satisfied, the output two ISI sequences are reciprocally related to input signals, and their oscillation wave shape in time course can be derived from that of the input signals variation, furthermore, the similar input sequence of order of UPOs, distribution of LES and value of KYD remain in attractors reconstructed from ISI sequences. But these phenomena will disappear in higher rate of stimulus activity or in changing of the strength of stimulus and coupling, for this situation, the ISIs shows bifurcate behavior. These results may be of vital importance for any kind of information processing based on the neurons and temporal coding.  相似文献   

4.
We present a neuro-mathematical model for geometrical optical illusions (GOIs), a class of illusory phenomena that consists in a mismatch of geometrical properties of the visual stimulus and its associated percept. They take place in the visual areas V1/V2 whose functional architecture have been modeled in previous works by Citti and Sarti as a Lie group equipped with a sub-Riemannian (SR) metric. Here we extend their model proposing that the metric responsible for the cortical connectivity is modulated by the modeled neuro-physiological response of simple cells to the visual stimulus, hence providing a more biologically plausible model that takes into account a presence of visual stimulus. Illusory contours in our model are described as geodesics in the new metric. The model is confirmed by numerical simulations, where we compute the geodesics via SR-Fast Marching.  相似文献   

5.
The dynamical behavior of spiral waves in a period-2 oscillatory medium is investigated under the influence of an external applied alternating current field. Open and closed transversal line defects which wiggle along the direction parallel to the wave fronts, are generated in the spiral-wave patterns when the stimulus frequency of the electric field is equal to one, three or five times of the local oscillatory frequency in the period-2 state. Their generations are directly related with the change in the spatial wavelength induced by the electric field. These wigglings proliferate along the transverse direction parallel to the wave fronts as the stimulus strength increases, and become denser when the stimulus frequency increases by multiples of the period-2 oscillatory frequency.  相似文献   

6.
Using a nonlinear circuit ruled by the FitzHugh–Nagumo equations, we experimentally investigate the combined effect of noise and a biharmonic driving of respective high and low frequency F and f. Without noise, we show that the response of the circuit to the low frequency can be maximized for a critical amplitude B1 of the high frequency via the effect of Vibrational Resonance (V.R.). We report that under certain conditions on the biharmonic stimulus, white noise can induce V.R. The effects of colored noise on V.R. are also discussed by considering an Ornstein–Uhlenbeck process. All experimental results are confirmed by numerical analysis of the system response.  相似文献   

7.
The goal of this article is to build an abstract mathematical theory rather than a computational one of the process of transmission of ideology. The basis of much of the argument is Patten's Environment Theory that characterizes a system with its double environment (input or stimulus and output or response) and the existing interactions among them. Ideological processes are semiotic processes, and if in Patten's theory, the two environments are physical, in this theory ideological processes are physical and semiotic, as are stimulus and response. © 2014 Wiley Periodicals, Inc. Complexity 21: 47–65, 2015  相似文献   

8.
This paper deals with the topological and measure theoretic probability foundations of metric multidimensional scaling. The first four sections develop minimal separation properties for a set of points or space to model a stimulus. The next three sections give measure theoretic probabilistic structure to random stimulus points and their random connecting paths.  相似文献   

9.
本文将Okada & Imaizumi等的模型加以推广,提出了一种用于处理非对称相异性矩阵的非度量多维尺度变换新方法.在模型中,我们假定每个研究对象可以表示为Minkowski度量空间中的一个点和一个超球面,超球面的半径揭示了相应研究对象的非对称性.文中我们给出了一种计算点坐标及球半径的算法.该算法使用了代数方法,比原来的方法收敛速度快,节省计算时间.最后给出了一个数值例子.  相似文献   

10.
The influence of interplay of external and internal noise on the detection of weak stimulus in a cell system was studied by using a mesoscopic stochastic model. When the stimulus was too weak to fire calcium spikes for the cell, separately, we found that calcium spikes could be induced by the external noise or internal noise, and internal signal stochastic resonance (ISSR) or internal noise stochastic resonance (INSR) occurred, respectively, so that the cell system could detect the weak stimulus through intracellular calcium spikes with the help of external noise or internal noise. When considering both of the noises, we found that internal noise could suppress ISSR, while external noise could enhance INSR in a certain range of external noise intensity. Interestingly, when the INSR occurs, the optimal size matched well with the real cell size, this was of significant biological meaning.  相似文献   

11.
研究外界场作用下,激发介质的波前曲率关系和波形变化· 理论分析波前曲率关系,得到外界场作用下,波前的法向速度与波前平均曲率、平面波速和外界场之间的线性关系· 数值分析外界场作用下,激发介质的Bar_Eiswirth模型,得到外界场作用下激发介质的波形图案· 这里的理论分析、数值结果与BZ反应的实验结果完全一致,从而解释了外界场作用下的BZ现象,且由数值结果可知激发介质包含丰富的波形图案·  相似文献   

12.
Strong economic growth and environmental regulation stimulus make Welsh small and medium enterprises' (SMEs) sustainability performance merit investigation in the context of European Union (EU) sustainability initiatives. This is due in part to strong economic growth and the stimulus provided by environmental regulation. We use stochastic frontier analysis, a parametric econometric technique to generate estimates of the technical efficiency of solid waste management by 299 Welsh SMEs in 2003. We demonstrate that the ranking and efficiency scores of the Welsh SMEs studied correlate significantly with non-parametric data envelopment analysis efficiency measures and are related to the use of environmental auditing practices and the use of local business support groups, but not to monitoring of waste expenditures and publication of environmental policies.  相似文献   

13.
Temporal organization of events can emerge in complex systems, like neural networks. Here, random graph and cellular automaton are used to represent coupled neural structures, in order to investigate the occurrence of synchronization. The connectivity pattern of this toy model of neural system is of Newman–Watts type, formed from a regular lattice with additional random connections. Two networks with this coupling topology are connected by extra random links and an impulse stimulus is either constantly or periodically applied to a unique neuron. Numerical simulations reveal that this model can exhibit a variety of dynamic behaviors. Usually, the whole system achieves synchronization; however, the oscillation frequencies of the stimulus and of each network can be different. The dynamics is evaluated in function of the network size, the amount of the randomly added edges and the number of time steps in which a neuron can remain firing. The biological relevance of these results is discussed.  相似文献   

14.
We focus on topological equisingularity of families of holomorphic function germs with 1-dimensional critical set. We introduce the notion of equisingularity at the critical set and prove that any family which is equisingular at the critical set is topologically equisingular. We show that if a family of germs with 1-dimensional critical set has constant generic Lê numbers then it is equisingular at the critical set, and hence topologically equisingular (answering a question of D. Massey [13]). It is worth to remark that this does not happen for higher dimensional critical set [5]. We use these topological triviality results to modify the definition of singularity stem present in the literature, introducing and characterising topological stems (being this concept closely related with Arnold?s series of singularities). We provide another sufficient condition for topological equisingularity for families whose reduced critical set is deformed flatly. Finally we study how the critical set can be deformed in a topologically equisingular family and provide examples of topologically equisingular families whose critical set is a non-flat deformation with singular special fibre and smooth generic fibre.  相似文献   

15.
S1 引言 Forcing方法假设存在ZFC的一个可数可传的模型M。记满足αM的最小序数α为,显然M中一切序数所成的集合即。由于M是ZFC的模型,故应具有某些性质。本文证明了它满足关系,故为ε数或1级关键数,进而证明了是H级关键数(H为任意自然数)。文中的记号等引用。  相似文献   

16.
研究一类具有非线性边界流的双重退化抛物方程组解的整体存在与爆破,通过构造自相似的上下解,得到了整体存在曲线.借助一些新的结果,获得了Fujita临界指数.其中一个有趣的现象是:整体存在曲线和Fujita临界曲线分别是由一个矩阵和线性方程组来决定.  相似文献   

17.
本文提出了一种确定重复性建设项目关键路线的新方法。借助约束线,首先给出了工序间存在各种约束条件(时间和距离约束)下潜在关键点的确定方法;为处理大规模项目,进一步提出了与图示法相对应的数值算法。以此为基础,提出了确定关键工序和关键路线的具体步骤,并定义和分析了三种不同类型的关键工序。与现有的方法相比,本文提出的确定关键路线的方法更为准确,适用性更强,而且有利于调度优化目标的实现。  相似文献   

18.
The critical point set plays a central role in the theory of Tchebyshev approximation.Generally,in multivariate Tchebyshev approximation,it is not a trivial task to determine whether a set is critical or not.In this paper,we study the characterization of the critical point set of S 0 1(△) in geometry,where is restricted to some special triangulations(bitriangular,single road and star triangulations).Such geometrical characterization is convenient to use in the determination of a critical point set.  相似文献   

19.
Markus Daub 《PAMM》2010,10(1):517-518
Apoptosis is an important physiological process since it enables organisms to remove unwanted or damaged cells. The stimulus of the extrinsic signalling pathway of apoptosis is the clustering of TNF-receptors on the cell membrane. We introduce a mathematical model for the clustering of TNF-receptors on the cell membrane. Numerical simulations yield a time evolution of the receptor clusters. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

20.
The mechanical vibrations have been perceived as unhealthy, although in some circunstances these may lead to a human body fortification. The trainings that use the vibrating stimulus have certain advantages to the classical trainings. Stabilizers and postural muscles are less visible, being hidden by large muscle groups and have little growth potential. For this reason most types of training does not focus on training and strengthening them. This article presents the advantages of training muscular groups of the vertebral column performed on vibrating plates. This type of training has the advantage that besides the requiring to all muscles in where the vibratory stimulus reaches, leads to an increase flexibility of joints. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

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