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1.
Dandan Yue Zhi-Hong Guan Juan Li Feng Liu Jiang-Wen Xiao Guang Ling 《Journal of The Franklin Institute》2019,356(5):2847-2869
In this paper, we study the local stability and bifurcation of a delay-coupled genetic regulatory networks consisting of two modes with the hub structure. By analyzing the equilibrium equation, the number of the positive equilibria is discussed in both the cases that there are inhibition coupling and activation coupling in the networks. It is revealed that multiple equilibria could exist in the developed genetic networks and the number of the equilibria could be distinct under the two cases of delayed-coupling. For the equilibrium, the conditions of the coupling-delay-independent stability and the saddle-node bifurcation are derived with respect to the biochemical parameters. The coupling-delay-dependent stability and the Hopf bifurcation criteria on the biological parameters and the coupling delay are also given. Moreover, the complexity of the algorithm used in this paper is analyzed. The numerical simulations are made to certify the obtained results. The multistability of the developed genetic regulatory networks is displayed. The different effects of the coupling delay on the stability of the genetic networks under different biochemical parameters are shown. 相似文献
2.
开放式创新要求企业跨越组织边界搜寻外部知识。为了识别“前瞻-反应型”二元搜寻平衡与企业发展阶段的动态匹配规律,基于我国中小企业调查样本进行实证分析,结果发现：平衡式搜寻对创新绩效具有显著的正向影响,但是企业在初创期和成长期的二元搜寻平衡模式存在差异。在初创期,前瞻型与反应型两类搜寻策略间不存在互补效应,且二元均衡程度过高或差异过大,均不利于企业创新;而在成长期,前瞻型与反应型两类搜寻策略间存在互补效应,且同时性平衡程度越高,创新绩效越好。据此探讨了企业在不同阶段的最佳平衡模式,即初创期的企业选择“间断性平衡”较为合适,进入成长期后,企业需要将平衡模式转换为“同时性平衡”。 相似文献
3.
M. Farshad 《Journal of The Franklin Institute》1978,305(3):125-135
A two-dimensional theory for the incremental deformations of an initially stressed continuum with couple stresses is established in this paper. As applications of theory, the problems of internal instability and wave propagation are studied. It is found that the otherwise non-dispersive waves become dispersive, and additional local modes of buckling and vibratory motion are observed. To complete the theory, a stress function formulation of equations is also presented. 相似文献
4.
概述了齿式联轴器的分类及特点,重点对鼓形齿式联轴器的特殊测绘部分作了介绍．强调了联轴器计算的反复性,同时也对鼓形齿式联轴器材料选用、热处理和润滑等作了大致的描述。 相似文献
5.
《Journal of The Franklin Institute》2023,360(2):964-984
As an important technology to improve network reliability, fault diagnosis has gained wide attention in complex dynamical networks. However, few studies focused on detecting the structure of broken edges when faults occur. In this paper, due to the natural sparsity of complex dynamical networks, a completely data-driven method based on compressive sensing is established to detect the structure of faulty edges from limited measurements. The least absolute shrinkage and selection operator algorithm is applied to solve the reconstruction problem. In addition, the method is also applicable to multilayer networks. The faulty edges in both the intralayer network and the interlayer network can be fully identified. Compared with other methods, the main advantages of the proposed method lie in two aspects. First, the structure of faulty edges can be obtained directly with limited measurements. Second, the proposed method is less time consuming and more efficient due to less data processing. Numerical simulations involving single-layer, multilayer and real-world complex dynamical networks are given to demonstrate the accuracy of detecting the structure of faulty edges from the proposed method. 相似文献
6.
Mario Porru Alessandro Serpi Ignazio Marongiu Alfonso Damiano 《Journal of The Franklin Institute》2018,355(2):728-752
Two different control approaches for suppressing DC-link voltage unbalance in Three-Level Neutral-Point Clamped Converters (NPCs) are presented in this paper. They both guarantee DC-link voltage equalization over any NPC operating conditions, i.e. when the NPC feeds or is supplied by the main AC grid at different active and/or reactive power rates. The proposed control approaches consist of either a hysteresis or a proportional regulator, each of which synthesizes the most suitable control action based on the actual DC-link voltage unbalance. Particularly, two different PWM techniques have been developed in order to achieve DC-link voltage equalization successfully, preserving NPC voltage and current waveforms at the same time. The performances achievable by means of both the proposed control approaches have been compared to each other through an extensive simulation study in order to highlight their most important advantages and drawbacks, as well as their effectiveness over any operating conditions. Particularly, both control approaches are validated in the Matlab-Simulink environment referring to DC-link voltage equalization of an NPC that represents the point of common coupling between a DC microgrid and the main AC grid. 相似文献
7.
责任承担是处理科研不端事件的落脚点。国际期刊规定不端责任人承担带有连带性质的共同责任,我国立法属意按份责任,两种承担方式各具优劣。科研不端中的责任是一套体系,但需要更多关注行政责任,兼顾民事责任,不同的责任性质对应不同的归责原则。根据研究结果,以外部责任和内部责任两分法构建适切的科研不端责任承担机制。 相似文献
8.
化妆与形体课程是当前普通高校传媒专业普遍开设的一门课程,它对学生的形象塑造和姿态的养成具有非常重要的意义。而当前高校化妆与形体课程教学中存在诸多乱象,教学模式、教学方法、教育理念和课程设置等方面没有统一的模式。本文作者结合自身多年来对播音主持专业学生的化妆与形体课程教学经验,对学生化妆与形体教学模式进行初探,以求建立一种规范化的教学模式,为播音主持专业发展做出贡献。 相似文献
9.
This paper explores trade-offs between knowledge exploitation and exploration activities. The study of exploitation and exploration activities is not new; however, rarely has past research perceived exploitation and exploration activities as two edges of one continuum. Furthermore, little evidence has been reported as to the actual trade-offs that firms face when launching either exploration or exploitation activities. This paper sets about filling this gap by addressing the following question: To what extent does an investment in one exploitation activity hinder the development of an exploration activity within the firm? A new process innovation targeting the exploitation of the firm's internal capabilities through an extensive component reuse and reconfiguration program is studied and the implications for inter-related exploration activities, such as the development of engineers' expertise is examined. To reveal the trade-offs between exploration and exploitation activities, both changes within and between these exploitation and exploration activities, over time, are studied. Based on data drawn from an in-depth study of several product development project teams in one high-tech company, we conclude that by investing in exploitation activities, a firm may limit some specific exploration activities. 相似文献
10.
在内向和外向开放式创新过程中,企业采取何种组织模式才能有效利用内部和外部的知识或技术是企业成功实施的关键所在。基于内向开放式创新和外向开放式创新的耦合关系,本文将内向开放式创新市场拉力路线图（MPRIOI）和外向开放式创新技术推力路线图（TPROOI）进行了整合。内向开放式创新企业在市场分析、产品分析和技术分析三个阶段,可分别采用非股权战略联盟、购买技术服务和购买技术授权的组织模式实现内向开放式创新;外向开放式创新企业在技术分析、产品分析和市场分析三个阶段,可分别采用非股权战略联盟、提供技术服务和提供技术授权的组织模式实现外向开放式创新。借助技术路线图方法帮助企业在在内部技术开发和外部技术开发之间进行决策,在内向开放式创新、外向开放式创新以及封闭式创新之间寻找到创新战略的最佳均衡点。 相似文献
11.
利用2006—2015年的统计数据,通过构建耦合协调模型,对广东各经济区域科技创新与经济发展两个子系统的耦合协调关系进行研究,结果表明:各区域的两子系统综合序参量值呈现较为一致的增长态势,且呈现较高的正相关,科技创新系统综合序参量值比经济发展系统综合序参量值增长得更快;各区域的科技创新、经济发展两子系统的耦合度和协调耦合度均呈现快速增长态势,且近年均达到高度耦合和高度协调耦合阶段,说明广东各区域科技创新和经济发展两者的交互作用较强。基于此提出建议:广东各经济区域坚持科技创新驱动发展战略,以产业为载体促进科技创新能力与经济效益双提升;珠三角地区深化机制体制创新,优化配置科技创新资源,培育经济增长的新动力;粤东西北地区注重提高科技创新在产业结构调整和升级过程中的支撑作用。 相似文献
12.
The cutoff wavenumbers knm and the field of surface wave modes of a circular cylindrical conductor eccentrically coated by a dielectric are determined analytically. The electromagnetic field is expressed in terms of circular cylindrical wave functions referred to both axes, in combination with related addition theorems. When the solutions are specialized to small eccentricities kd, where d is the distance between the two axes, exact closed-form expressions are obtained for the coefficients gnm in the resulting relation knm(d)=knm(0)[1+gnm(knmd)2+...] for the cutoff wavenumbers of the waveguide. Similar expressions are obtained for the field. Numerical results for all types of modes are given. For certain values of the parameters, it is possible to enhance the operating bandwidth of the basic hybrid mode HE11 over the conventional concentric guide. 相似文献
13.
Each graph may be associated with a certain function called its generic form. If one knows the generic forms of given graphs, then one can easily determine the number of spanning trees in graphs obtained from a complete multi-graph either (1) by adding, or (2) by deleting the edges of disjoint copies of the given graphs. Our obejective here is to give a proof of a simple and useful relation between the generic forms of graphs that are complementary with respect to a complete multi-graph. 相似文献
14.
基于2009-2017年中国东部沿海三大城市群34个城市面板数据,运用耦合协调度模型和障碍度模型, 厘清科技创新与绿色发展的耦合协调关系及其障碍因素的空间异质性特征。结果表明：三大城市群科技创新和绿色发展指数保持平稳增长状态,指数均值由大到小依次为珠三角、长三角和京津冀城市群,城市群内各城市发展存在显著不均衡;三大城市群科技创新与绿色发展耦合协调关系不断改善,珠三角和长三角城市群处于磨合阶段,京津冀城市群尚处于拮抗耦合阶段,三大城市群整体表现为失调型,协调关系仍需进一步改善;三大城市群各参数对科技创新与绿色发展协调发展的影响呈趋同性,创新投入、产出、储备及绿色生活建设是制约三大城市群科技创新与绿色发展的主要障碍因素。 相似文献
15.
从软件外包看中国软件企业的发展与创新 总被引：3，自引：0，他引：3
全球软件企业的发展模式主要有三种：美国模式、印度模式和日本模式。全球软件外包市场规模已达到1000亿美元，发包市场主要集中在北美、西欧和日本，接包市场主要是印度和爱尔兰。中国软件企业发展软件外包。需要注意国内国际市场并重，深化对日软件外包，借鉴印度模式拓展欧戋市场，重视CMM等业务流程管理，以文化为先导，加强教育培训和通过创新提升软件外包价值链。 相似文献
16.
Catalytic Janus particles rely on chemical decomposition to self-propel and have displayed enormous potential for targeted drug delivery and cellular penetration. Catalytic propulsion mechanisms are limiting, however, with fuel requirements and specialized fluid properties being necessary to achieve propulsion. We have improved the dynamic propulsion of catalytic Janus particles by functionalizing flagellar filaments to one of their hemispheres. Flagellated Janus particles, torqued by rotating magnetic fields, swim along their rotation axis using the explicit chirality and flexibility of flagella, mimicking flagellar rotation of live bacteria. Depending on the working fluid, flagellated Janus particles can propel using either catalytic or swimming propulsion. We demonstrate experimentally that flagellated Janus particles behave predictably under the two actuation modes and can precisely follow trajectories under closed-loop feedback control. Flagellated Janus particles were demonstrated to swim in both Newtonian and shear-thickening fluids. These are the first Janus particles developed that can be propelled interchangeably between catalytic and flagellar swimming propulsion, allowing two distinct propulsion mechanisms for future use within in vivo operations. 相似文献
17.
本文介绍了火力发电厂电气控制系统的两种控制模式,即电气现场总线控制系统（EFCS系统）和电气控制管理系统（ECMS系统）,并对这两种控制模式的主要设计模式和监控对象进行了分析比较。ECMS系统不与DCS系统通信,没有减少电气设备进入DCS系统的I/O硬接线。在EFCS系统方案中,小型电动机采用＂全通信＂监控方式进DCS系统,大型电动机及其他电气设备采用＂通信＋硬接线＂监控方式。E-FCS系统与DCS系统进行了网络互联,实现了信息共享,避免了信息重复采集,从而减少了设备和电缆成本及运行维护费用。 相似文献
18.
This paper analyzes synchronization in finite time for two types of coupled delayed Cohen–Grossberg neural networks (CDCGNNs). In the first type, linearly coupled Cohen–Grossberg neural networks with and without coupling delays are considered, respectively. In the second type, nonlinearly coupled Cohen–Grossberg neural networks both with and without coupling delays are discussed. By designing suitable controllers and using some inequality techniques, several criteria ensuring finite-time synchronization of the CDCGNNs with linear coupling and nonlinear coupling are derived, respectively. Moreover, the settling times of synchronization in finite time for the considered networks are also predicted. In the end, the availability for the acquired finite-time synchronization conditions is confirmed by two selected numerical examples. 相似文献
19.
Forms of knowledge and modes of innovation 总被引：5，自引：0，他引：5
This paper contrasts two modes of innovation. One, the Science, Technology and Innovation (STI) mode, is based on the production and use of codified scientific and technical knowledge. The other, the Doing, Using and Interacting (DUI) mode, relies on informal processes of learning and experience-based know-how. Drawing on the results of the 2001 Danish DISKO Survey, latent class analysis is used to identify groups of firms that practice the two modes with different intensities. Logit regression analysis is used to show that firms combining the two modes are more likely to innovate new products or services than those relying primarily on one mode or the other. The paper concludes by considering the implications for benchmarking innovation systems and for innovation policy. 相似文献
20.
在过去20年中,英国在创意产业领域推行了一系列校企合作计划,旨在弥补小微企业知识缺乏、促进其不断创新.以此为例进行分析可知,英国促进小微企业创新的校企合作政策,在知识服务内容上注重为小微企业提供创新所需的各类知识,在知识服务方式上根据不同的服务目的 和知识特性而运用相应的知识生产或转移规律,同时充分考虑小微企业作为知识服务对象的弱势与多样性,从而能充分、有效、个性化地促进小微企业创新.英国经验对我国以校企合作促进小微企业创新主要有3点值得加以借鉴:首先,加强对大学服务企业规律的研究;其次,建立各类大学与大型企业服务联盟;最后,发挥大学对地区行业的有针对性支撑作用. 相似文献