种间作用的二维非线性动力系统模型及其数值模拟试验研究

系统探讨了种间制约作用的二维非线性动力系统的机理与过程，从生物力学角度扩展了Lotka—Volterra模型，建立了包含种间作用与反作用的二维非线性自治、非自治动力系统新模型，分析了该动力系统平衡点的稳定性、周期解的存在性与稳定性，并对其动力学过程进行了数值模拟试验研究．结果表明两生物种群间作用效率的大小、作用系数与反作用系数变化的同向与异向性和作用力时变等对动力系统稳定性都有一定影响，种间作用效率变大或变小，以及作用系数与反作用系数的异向变化都导致动力系统的不稳定，致使两种生物难以生存，而相互作用力时变则对系统的稳定起促进作用．     

具两系统切换的脉冲阶段结构单种群动力学模型研究

建立具两系统切换脉冲阶段结构单种群动力学模型,利用离散动力系统频闪映射理论,得到系统种群灭绝与系统种群持续生存的控制阈值.结果表明脉冲收获与冬眠期对于系统种群持久起着重要作用,从而为现实的生物资源管理与生物多样性保护提供了可靠的策略依据.     

一类具有Lotka-Volterra竞争模型共存解的存在性与稳定性

该文讨论了在空间分布不均匀的环境下一类具有Lotka-Volterra二维竞争模型的共存解的存在性与稳定性.特别地,两个竞争物种被假设拥有不同的内禀增长率,不同的种内竞争系数和种间竞争系数.结果表明当扰动参数Υ充分小时,该模型的动力学行为被一些函数所刻画.该文使用的数学方法包含Lyapunov-Schmidt分解法,谱理论和单调动力系统理论.     

寄生调节的种内捕食特征变化对集团内捕食系统的影响

寄生可以通过直接或者间接的方式对物种间相互作用产生影响,进而影响集团内捕食系统的种群动态及物种共存.建立一个新的集团内捕食系统模型,考虑了种内捕食特征调节效应的影响结果,并探讨了易感染者和已感染者两种种内捕食强度变化对物种共存的调节机制.研究显示:两种不同特征调节下的种内捕食作用对物种延续和共存的影响也不尽相同,在一定范围内增大易感染种内捕食力度能够增大物种共存的区域,有利于提高物种多样性,保护濒危物种;而已感染种群种内捕食强度减弱则抑制物种共存,这一结论为解决有害生物入侵,保护本土生物提供了理论参考.综上所述,该研究在一定意义上充实了特征调节效应的影响机制.     

两种群竞争模型的定性分析

讨论两种群竞争系统解的渐进性态，其中两种群各自具有阶段结构和种内自食，在没有自食现象发生的条件下，分析了阶段结构的竞争系统的种群共存和灭绝，最后考虑自食的作用，得到了种内自食既可以维持种群共存，也可以挽救种群灭绝。     

生物数学——Ⅲ.数学与竞争排斥、竞争共存生态系统

<正> 研究竞争排斥与竞争共存生态系统的基本单位是在一个孤立的地理区域中由生活在一起的某些种群组成的理想化的生物群落.有趣的问题是种群之间为了争夺有限资源和生活空间而进行着斗争,斗争的结果必有某些种群趋于灭绝,这就是竞争排斥;或者,所有的种群保持某种相对的稳定性,这就是竞争共存.我们假定每一种种群在这区域上分布是均匀的,基本变量是每一种群的密度,这样就可以用微分方程来描述群落动力学.     

具有阶段结构的竞争系统中自食的稳定性作用

该文讨论了两种群竞争系统解的动力学行为，其中一种群分幼年，成年两阶段，当不考虑自食时，得到了阶段结构的竞争系统也可以出现三种典型的动力学行为，共存（coexietence)，双稳定（bistability),占优（dominance)，进一步，在没有自食时竞争系统是占优的情形下，考虑自食的影响，得到了所有种群永久持续生存的充分条件，这表明自食有稳定性的作用。     

一类具有离散时滞的非自治扩散的两种群模型的一致持续生存

持续生存概念是种群生态系统稳定性的一个重要描述,而研究竞争种群共存的问题是种群生态学的一个重要问题.进一步考虑具有离散时滞的非自治的两种群竞争扩散摸型,使模型更符合其生态意义,通过微分不等式获得了其一致持续生存的充分条件.     

具脉冲效应的阶段结构单种群动力学模型

讨论了生物资源管理中的具脉冲出生与脉冲收获的单种群阶段结构动力学模型.利用离散动力系统频闪映射理论,得到了脉冲投放幼体对整个种群持续生存的重要意义.为现实的生物资源管理提供了可靠的策略依据,也丰富了脉冲微分方程理论.     

基于Type-2模糊贴近度在生态上的应用

分析比较了Type-1模糊贴近度与Type-2贴近度的特点,并将Type-2模糊贴近度的概念和相应运算应用到生态系统中,给出了物种动态的生态位模型,计算了物种实际生态位与理想生态位的重叠,根据重叠的精确值和区间值分别研究了物种进化的动态行为和进化程度.     

基于系统动力学的地方政府与制造企业碳减排演化博弈分析

为探究中国在碳减排政策下地方政府与制造企业双方的博弈关系,在分析地方政府和制造企业不同策略下的成本和收益的基础上,采用系统动力学方法构建了地方政府和制造企业之间的静态混合策略演化博弈模型;进一步引入政府动态惩罚和补偿策略,剖析政企双方策略的互动机制。分析结果表明:地方政府对企业是否采取碳减排措施的奖惩力度、企业采取碳减排措施的成本与收益,会直接影响博弈结果;地方政府和制造企业两个群体在三种情况下存在演化稳定策略;在一定条件下,系统演化呈现周期性特征;当地方政府实施动态惩罚或补偿措施时,该博弈模型存在稳定的Nash均衡点。     

A mutualism-competition model characterizing competitors with mutualism at low density

A macroscopic model of two species is considered, in which mutualism is the dominant interaction when the species are at low density and competition is the dominant interaction when they are at high density. Our aim is to show that species using the same or similar resources can coexist without niche differentiation and that mutualism at low population density can lead to high production. The specific model is a novel combination of the Lotka–Volterra cooperative (mutualism) model and Lotka–Volterra competitive model. By comparing the dynamics of the specific system with those of the Lotka–Volterra competitive model, we demonstrate the mechanism by which the mutualism at low density promotes competitive coexistence by creating regions of mutualism that maintain coexistence. We also show situations in which high production occurs by (i) displaying regions of net mutualism in which the species with higher competitive ability (the superior) approaches a density larger than its carrying capacity when in isolation from the inferior species, and (ii) displaying regions of net mutualism in which both of the species approach densities larger than their carrying capacities, respectively. By comparing the dynamics of the specific system with those of the Lotka–Volterra mutualism model, we show that competition at high density promotes stability of the system.     

Effects of time-lagged niche construction on metapopulation dynamics and environmental heterogeneity

Time-delayed responses to environmental changes and disturbance can beget profound effects on the spatiotemporal dynamics of metapopulations. Here, we first examined the effect of three forms of time-lag (that is, equal-weight, recency and primacy effects) on population dynamics, using a spatially structured lattice model. The time-lag was incorporated in the niche construction process of the system (an organism–environment feedback). Using bifurcations diagrams and numerical simulations, we found that the time-lag can form a phase-locked oscillation. Three typical spatial patterns emerged: spiral wave, spiral-broken wave and circular wave. These spatial patterns gradually become immobile as a result of the self-organized ecological imprinting due to niche construction. Therefore, the phase-locked oscillation and the ecological imprinting process together determine the spatial structure of metapopulations and the environmental heterogeneity.     

供应链网络道德风险演化与仿真研究

针对目前供应链网络存在的越来越严重的道德风险问题,利用演化博弈和系统动力学理论,从供应链网络结构入手,对其演化过程进行了研究。首先基于供应商之间合作过程中的诚信和败德行为,建立供应链网络同级企业间道德风险的演化博弈模型,并分析了其演化路径。其次通过对制造商和供应商之间博弈的动态性分析,建立供应链网络上下游企业间道德风险演化的SD模型,并对其演化过程进行了仿真分析。研究结果表明:供应链网络道德风险的演化结果取决于网络内败德企业获得的超额收益、收益调整程度、惩罚力度和惩罚机制。另外,罚款力度大小与供应链网络道德风险演化的动态性密切相关;动态惩罚机制在其演化的波动性控制方面,具有明显效果。     

协同创新主体合作的演化博弈及政府干预的仿真

文章首先基于演化博弈理论,研究了无政府干预下协同创新主体采取合作策略的演化博弈规律;其次基于系统动力学理论,分析了政府干预下协同创新主体采取合作策略的演化博弈规律,并构建了系统动力学模型及运用Vensim软件作出了仿真分析。仿真发现,协同创新主体间的合作主要受政府惩罚力度、采取的惩罚机制以及创新主体采取投机行为所产生的生产成本的影响。因此,政府提高惩罚力度并采用动态惩罚机制,能促使协同创新主体更快地采取合作策略进行协同创新。     

Strong competition model with non-uniform dispersal in a heterogeneous environment

In this study, a strong competition model was considered between two species in a heterogeneous environment. For a system with two different constant diffusion rates for each competitor, the fast diffuser can be selected evolutionally under suitable assumptions if the competing interaction between the species is strong. We also claim that a strongly interacting competition leads to a more evolutionary selection than that with the same population dynamics if a species moves with a certain non-uniform dispersal. Furthermore, species with a certain non-uniform dispersal have a competitive advantage over linear random diffusers. In addition, a species with highly sensitive dispersal response to the environment may survive. These strongly competitive advantages were demonstrated by investigating the stability of semi-trivial solutions of the system with non-uniform dispersal and comparing it to the conditions of the model with constant diffusion.     

基于系统动力学的政府和废旧电子产品处理商演化博弈分析

文章为探究政府管制在废旧电子产品处理商实施生态拆解的作用,运用系统动力学方法构建了废旧电子产品处理问题中政府和处理商之间的一个混合策略演化博弈模型,并对政府管制策略选择与处理商实施生态拆解策略选择的互动机制进行了分析。演化博弈和系统仿真结果表明:处理商实施生态拆解和非生态拆解的收益、政府管制的有效性以及处理商实施非生态拆解受到惩罚等都直接影响系统的演化结果;政府和处理商两群体在3种情形下存在演化稳定策略;在一定的条件下,系统演化呈现周期性特征。最后从政府管制的角度出发,动态策略的演化博弈模型存在演化稳定的均衡点。     

基于演化博弈视角下的加盟式快递合作稳定性分析

针对我国加盟式快递企业逐渐暴露出的加盟商服务质量低下、各自为政、总部管理薄弱等引发的双方合作不稳定问题, 本研究以演化博弈模型为主要理论工具, 开发了不完全信息下快递公司总部和加盟商的行为交互演化博弈系统。通过雅克比矩阵求解, 揭示了博弈初始条件改变以及决策参数取值变动对演化稳定结果的影响;然后以申通公司为例, 采用MATLAB软件进行了数值仿真分析。研究表明, 当加盟商积极合作所增加的收益、快递公司总部的罚金、信息不对称程度和监督成本位于不同阈值区间时, 系统分别呈现出三种演化稳定结果和一种周期性的随机状态, 同时发现快递单价对促进博弈双方的合作稳定性具有积极作用。最后, ①降低快递加盟商服务成本, 提高服务质量;②建立适度的违约惩罚制度, 完善利润分配机制;③加强平台信息共享, 促进信息透明化;④营造良好的竞争氛围, 避免无谓的价格战, 有助于引导系统向理想状态演化。     

Approximate and Widespread Pareto Solutions in the Structure-Control Design of Mechatronic Systems

The structure-control design approach of mechatronic systems requires a different design formulation where the mechanical structure and control system are simultaneously designed. Optimization problems are commonly stated to confront the structure-control design formulation. Nevertheless, these problems are often very complex with a highly nonlinear dependence between the design variables and performance functions. This fact has made the use of evolutionary algorithms, a feasible alternative to solve the highly nonlinear optimization problem; the method to find the best solution is an open issue in the structure-control design approach. Hence, this paper presents a mechanism to exhaustively exploit the solutions in the differential evolution (DE) algorithm in order to find more non-dominated solutions with uniformly distributed Pareto front and better trade-offs in the structure-control design framework. The proposed approach adopts an external population to retain the non-dominated solutions found during the evolutionary process and includes a mechanism to mutate the individuals in their corresponding external population region. As a study case, the structure-control design of a serial-parallel manipulator with its control system is stated as a dynamic optimization problem and is solved by using the proposed approach. A comparative analysis shows that the multi-objective exhaustive exploitation differential evolution obtained a superior performance in the structure-control design framework than a DE algorithm which did not consider the proposal. Hence, the resulting designs provide better trade-offs between the structure-control performance functions.     

The distribution of wealth and the effect of extortion in structured populations

Despite that the heterogeneous distribution of wealth is widely observed in social, economical and biological system, few studies have been conducted to explore its influence on the evolutionary dynamics in populations. This paper discusses this problem by introducing a heterogeneous wealth allocation mechanism controlled by a tunable parameterα . Our study shows that there is a positive relationship between the level of cooperation and the extent of heterogeneity of wealth distribution. More importantly, we show that the catalytic effect of extortioners can be significantly strengthened if wealth is heterogeneously distributed among the whole population. Cooperators and extortioners can co-exist if the value of αis moderate. We explain this phenomenon by arguing that this heterogeneous allocation mechanism enables three types of strategists to form clusters around several rich cooperating neighbors initially. Clusters of defectors tend to be eliminated at early stages of evolution.