害虫种群尖点突变模型的几何分析

基于尖点突变的性质,对修改后的Logistic模型进行变换,并将其化为具有尖点突变的标准模型.利用微分方程定性理论,对模型进行分析,并根据突变理论,给出突变发生的条件.最后利用仿真验证结论的正确性.     

基于尖点突变的知识应用过程中溢出效应研究

本文引入“知识浓度”和“知识应用速度”两个概念,利用知识稀释效应的系统动力方程解释知识溢出机理。从突变视角分析了知识溢出的突变特性,借鉴尖点突变理论对系统动力方程进行换元变换,建立了知识溢出状态的尖点突变模型,讨论了知识稀释系统控制因子的变化与知识溢出状态间的判定规则,说明了知识应用过程中知识溢出特性如突跳、滞后效应等特性及知识溢出态和接受态之间转化的尖点突变机理。最后,利用我国31个省级行政区面板数据进行实证研究,揭示以省级行政区为对象的知识溢出状态、变化情况及发展趋势,为我国区域经济发展和知识战略提供理论指导。     

薄壁压力管道的突然破裂

用数学的突变理论研究薄壁圆形管道在内部爆炸力作用下的脆性破裂问题。在弹性能量准则基础上,建立了管道壳体破裂的尖点突变模型,给出了相应的破裂临界条件。     

不确定环境下基于交叉评价的模糊综合评价方法

由于环境的不确定性,多属性决策中客观数据和主观因素并存,决策者很难做出精准的评判.借鉴DEA交叉评价的思想,将量化数据用交叉评价方法进行处理,得出平均交叉效率值作为模糊综合评价的指标进行二次评价.建立了不确定环境下基于交叉评价的模糊综合评价模型,并通过评价实例验证了模型的客观、全面性.     

基于改进DEA——以复相关系数为基准的滞后期的我国产业结构演化效率评价

为了评价我国的产业结构演化效率,本文构建了我国产业结构演化评价指标体系。针对传统DEA方法的局限性,文中引入以复相关系数为基准的滞后期,解决了产业结构演化评价中投入和产出之间的滞后性问题,建立更加有效的DEA改进模型,对我国产业结构演化效率进行评价。结论表明,各产业技术效率大部分时间大于规模效率,而且投入要素出现不同程度的冗余情况,近年来,第一、二产业固定资产投资和就业人员冗余程度有减轻的趋势,第二产业能源和水资源消耗较大,同时第三产业各要素冗余程度均有所加深。针对这一现象,本文提出了相关对策建议。     

突发事件影响度的仿真研究

以突变理论为基础,给出了突发事件影响度的仿真评价方法.通过采用三角分布描述专家对子指标影响程度的估计,建立了突发事件影响度的仿真模型.通过对仿真模型进行独立重复仿真实验,获得突发事件影响度的评价值并进行统计分析.为克服评价结果偏高而区分度不高的缺陷,研究了评价值的转换方法,转换后的评价值能更好地体现人们对突发事件的认知程度.该方法可将定量、定性指标纳入同一模型中,并可避免人为确定权重的主观性.算例表明,在基于突变理论的评价模型中结合系统仿真的思想,是研究突发事件影响度的有效方法.该方法具有良好的可靠性,也可适用于其它综合评价问题.     

基于TOPSIS的网络舆情态势等级模糊多指标综合评价模型

网络舆情是社会舆情在网络空间中的映射,体现了社会稳定和谐程度.网络舆情态势分析对于有效预测和把握舆情导向具有重大的意义.文章主要研究构建基于TOPSIS的网络舆情态势等级模糊多指标综合评价模型.首先,根据网络舆情态势演化形成原因和发展规律,建立了网络舆情态势等级评价三级指标体系,提出了基于有序比值方法的网络舆情态势等级评价指标权重的确定方法.然后,构建了基于TOPSIS的网络舆情态势等级模糊多指标综合评价模型.最后,通过魏则西事件验证了该模型的有效性和适用性,并与线性加权综合评价模型进行对比分析,说明了文章模型的优越性.研究结果对政府和相关舆情监管人员及时有效的管理和引导网络舆情具有重要的指导意义与参考价值.     

基于相关性分析与DEA模型的寿险公司效率分析

选取国内较有影响力的八家寿险公司作为研究对象,提出了基于相关性分析的DEA组合评价方法,该方法综合了相关性分析和DEA两种方法的优点.利用相关性分析的方法设计出评价寿险公司经营效率的投入和产出指标.然后综合运用DEA模型对这八家公司的经营效率进行研究,分析影响效率有效性的因素.     

基于熵权法的农产品流通效率模糊综合评价研究——以河南省为例

为了解决因生产者、消费者与中间流通商的利益博弈而出现的农产品流通环节的卖难买贵问题.在考虑指标数据可获得性、评价方法科学性以及指标体系全面性的的情况下,基于2011-2017年河南省统计年鉴和中国统计年鉴数据,建立了一种基于熵权法和模糊综合评价方法的农产品流通效率组合评价模型,并对河南省2010-2016年农产品流通效率进行了实证研究.结果表明,2010-2016年河南省农产品流通效率最大隶属度逐年递增,趋势与熵权法中求得的河南省农产品流通效率综合得分变化相一致.体现了该组合模型在农产品流通效率评价中的适应性与准确性.     

非期望产出的DEA效率评价

将非期望产出作为投入应用到传统DEA模型上,解决了非期望产出生产活动的效率评价问题.结合生产可能集,将非期望产出直接反映到生产可能集中,建立了基于投入导向的径向和非径向两种DEA模型.并对两种DEA模型效率值的大小关系、相对有效性的等价性问题进行了证明,指出非径向DEA模型更能准确的实现效率定量评价.     

一种面向效率的系统多序参量识别方法

针对社会组织系统演化过程中效率性要求,基于系统演化有效性识别及评估,提出能够反映系统演化过程效率的多序参量识别方法,为提升系统演化过程效率提供可操作的技术参考。通过产出/投入视角分析多序参量形成过程,结合其对系统演化过程的影响,给出基于产出/投入的系统演化过程中多序参量效率原理;应用改进的数据包络分析方法和已有指标体系,建立面向效率的系统演化过程多序参量识别模型。最后,通过算例验证方法的科学有效性。     

Theoretical reconciliation of equilibrium and structural approaches

This paper shows that the solution space of Hamiltonian models of economic production and growth is intrinsically catastrophic (unless constrained by excessively stringent restrictions on technology and information). The paper explores cusp and fold deformations which are tied to organizational and informational processes. In turn, these processes are shown to be well represented by structural models in which cellular-automata simulate the reorganization of sequential machines.     

具有偏好锥的面向输出的超效率DEA模型分析

鉴于传统DEA模型无法区分有效决策单元,超效率DEA模型未考虑决策者的偏好,现提出面向输出的权重受限的综合超效率DEA模型及其投影概念,并讨论该模型与其他超效率DEA模型之间的关系.接着,分析模型的最优目标函数值与决策单元有效性之间的关系,并讨论面向输出的权重受限的综合超效投影与多目标规划问题的非支配解之间的关系.最后,通过对中国西部12个地区工业企业科技创新效率综合评价,并与原有方法进行比较研究,得出本文方法更具优势和合理性.     

Economic applications and statistical analysis of the cusp catastrophe model

The cusp catastrophe model provides a useful tool for the analysis of several interesting phenomena (e.g.,hysteresis, divergence, abrupt changes), which are usually assumed away in economic modelling. This paper surveys the applications of the cusp in economics and derives estimates for the parameters of the equilibrium and the disequilibrium model based an the method of moments and the maximum likelihood method. Moreover, we present a hypothesis test that enables us to compare the cusp (nonlinear) model with a traditional (linear) model by means of statistical data.An earlier version of this paper was presented at theX. Symposium on Operations Research (Munich 1985) and at the Annual Meeting of the Austrian Society of Operations Research (Vienna 1985). We are indebted to Loren Cobb for generously providing his cusp analysis program.     

LQR Control for Vibration Suppression of Piezoelectric Integrated Smart Structures

In the present paper, the equations of motion for piezoelectric integrated smart beams are derived by applying Hamilton's principle and the Finite Element (FE) method, based on the First-Order Shear Deformation (FOSD) theory. Then, a state space model is constructed from the equations of motion for control design. A Linear Quadratic Regulator (LQR) control for vibration suppression is implemented on the mathematical model of the piezoelectric bonded beam. Finally, a numerical application is performed to testify the applicability and effectiveness of the present method. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Interval differential evolution with dimension-reduction interval analysis method for uncertain optimization problems

A constrained nonlinear interval optimization method under the framework of differential evolution algorithm is developed to solve the uncertain structural optimization problems with interval uncertainties. The proposed method is a direct optimization method based on the interval differential evolution and dimension-reduction interval analysis. The interval preferential rule based on the satisfaction value of interval possibility degree model is used to realize the direct interval ranking of different design vectors. At each evolutionary generation, the outer optimizer by differential evolution optimizer searches for the best solution within the design space. The dimension-reduction interval analysis is employed to calculate the intervals of objective and constraints for each design vector in the inner layer. This operation transforms the original nesting optimization problem into a single loop one which improves the computational efficiency of the proposed method. Finally, the effectiveness of the presented direct method is verified by two numerical examples and an engineering application.     

Biodegradation of substitutable substrates in a continuous bioreactor with cell recycle: A study of static bifurcation

The static bifurcation of an unstructured model of a continuous bioreactor with cell recycle involving the biodegradation of mixed wastes is analyzed using the singularity theory. The biodegradation of the dissimilar substrates follows Andrew's inhibitory kinetic models. It is shown that the steady state locus of the model can be described by a polynomial of seven order. The stability analysis shows that the model exhibits a number of singularities, including hysteresis and pitchfork that occurs at clean feed conditions. It is also shown that the model cannot predict isola, mushroom, or winged cusp singularities. The effect of the model kinetic and operating parameters on its stability characteristics are also discussed.     

The time operator of the cusp map

We construct the natural time operator for the discrete dynamical system generated by the cusp map and give explicitly the age eigenfunctions which provide a shift representation of the evolution allowing for probabilistic prediction. In contradistinction, the construction of the spectral decomposition of the cusp map is not an easy problem.     

电信技术选择管制的突变模型

"追捧效应"、"市场锁定"一直是电信产业技术选择的奇特现象,突发性的变化后是持续性的稳定,电信技术市场突发性的变革令传统经济分析难以找到解释的途径.系统理论的最新研究成果同时表明,以均衡分析研究经济是不足以反映客观现实的.电信技术的迅猛发展,动态化特征加剧,更使均衡分析没有用武之地.以系统论的观点分析电信产业技术的市场化突变是本文的主要内容.通过建构电信技术选择管制的突变模型,得出电信技术选择突变产生的系统条件.     

The sliding mode control for an airfoil system driven by harmonic and colored Gaussian noise excitations

This paper addresses a sliding mode control (SMC) for an airfoil model excited by a combination of harmonic force and colored Gaussian noise. Firstly, to reveal effects of random factors, the airfoil model with colored Gaussian noise is established. Next, via a perturbation technique and the stochastic averaging method, an analytical expression for the time-averaging mean square response is derived, which agrees well with results by Monte Carlo simulations. Additionally, we uncover that colored noise can induce a stochastic jump phenomenon, which can cause a catastrophic structural failure of the airfoil or even a disintegration of the aircraft. Subsequently, the SMC strategy is employed to design an effective controller for suppressing such a jump phenomenon of the stochastic airfoil system. In the case of the proposed stochastic airfoil system, we introduce concepts of ultimately reachability with an arbitrary small bound and a mean square practical stability to realize the reachability of the sliding mode and the stability of the system state. Finally, several numerical results are presented to demonstrate the effectiveness of the proposed SMC algorithm. We show that the jump phenomenon can be suppressed efficiently to avoid a catastrophic failure of the wing structure due to large deformation/deflection, and the energy cost is discussed to analyze the SMC approach.