灰色GM(1,1)预测在病虫测报上的应用

前言 灰色预测是从过去或当今的信息预测未来信息,这些信息对未来事件预测可能是不充分的,称之为“灰色”。病虫发生受气候、天敌等生态条件及本身条件的制约,而且现有信息与未来信息的关系是不十分明确的,从而是“灰色”的,近年来,我们运用灰色预测对麦蚜、粘虫、玉米螟进行了预报,取得了较好的效果。 农业生态系统是由若干子系统组成,子系统相互独立又相互依存,病虫本身是一个子系统,受其它因素影响较大,每年发生差异较大,一般不成平稳序列。直接用GM(1,1,)建模,拟合率较差,所以,我们必须对历年数据进行处理,由于数据处理方法不同,可分为…     

R-fuzzy集的优势测度及其在人类感知领域中的应用研究

给出了一种新颖的R-fuzzy集优势测度的定义,实现了R-fuzzy粗糙近似集与描述符相关的隶属度重要性的量化表示.指出了优势测度是R-fuzzy集隶属度重要性的度量工具,并且具有传统Zadeh模糊集的本质属性.然后,针对不同标准子集对于隶属度集的优势测度序列,采用灰色绝对关联分析的方法对标准子集在隶属度评价方面的差异性进行了量化研究.最后,基于优势测度概念及灰色绝对关联分析方法对观音机场展开了噪声感知实验,讨论了不同年龄评价群体对噪声的理解在优势测度上的差异,证实了优势测度在人类感知辨识领域内的应用价值.     

交通流灰色RBF网络非线性组合预测方法

针对智能交通系统的开发,提出一种基于灰色GM(1,1)模型和RBF网络非线性组合的短时交通流预测方法.该方法采用三层结构的RBF网络将两种单一预测方法(灰色GM(1,1)模型和RBF网络)进行了非线性组合.利用实测数据对组合方法进行了仿真实验,结果表明:非线性组合模型的预测准确性高于单独的RBF网络预测的准确性;组合模型发挥了两种单一方法各自的优势,是短时交通流预测的有效方法.     

区间灰色对策的灰色核心和灰色稳定集

本文建立了一种新的包含有灰色信息的合作对策模型-区间灰色合作对策,研究了其区间灰色核心和区间灰色稳定集的结构,给出了这类核心及稳定集的一些特征和性质,并加以证明。灰色合作对策对研究具有灰色信息的合成对策具有一定的参考价值。     

关于粗糙集和灰色系统之间某些关系的探讨

首先介绍粗糙集与灰色系统两种理论,并对二者进行比较。接着介绍普通粗糙集、P-粗糙集以及灰色集的定义,并就灰色集、模糊集和经典集合三者进行对比分析。我们提出了点灰度和集灰度两种灰度概念用于描述灰色系统的信息不确定性。通过P粗糙集导出相应的灰色集,并研究相关的灰度、粗糙度与边界域的性质和关系。分析表明使用导出的灰色集对系统的信息不确定性的估计与相应的粗糙集是一致的,因此两种理论在描述和处理不确定性信息系统方面的一定的相关性,将两种理论相结合来处理某些不确定性信息系统可能更为有效。     

基于灰色白化权函数聚类的飞行员进近着陆操纵品质评估指标遴选

飞行员进近着陆操纵行为评估合理指标的确定是实施飞行品质监控与绩效评估关键.通过灰色聚类分析理论优势分析,构建了灰色白化权函数聚类分析模型.结合专家调查法确定指标重要程度评分标准以及评分矩阵,建立指标重要程度对应的灰类等级以及白化权函数,计算出指标重要程度灰色统计系数、灰色统计数以及权向量,设定指标阈值区间遴选出飞行员进近着陆操纵品质评估保留指标以及暂留指标,为实施飞行员进近着陆操纵品质评估提供基础.     

基于组合赋权灰色关联模型的职业技术类高校教师绩效评价

针对职业技术类高校教学特点,构建合理突出优势的教师绩效评价体系.首先结合职业技术类高校的人才培养基本要求,从师德师风、人才培养、科学研究、社会服务四个方面构建指标.采用专家打分法确定四方面的权重,再根据熵权法与变异系数法两种客观赋权法对细化的评价指标进行求权处理,并将主观赋权与客观赋权法相结合确定最终指标权重.本文对八位教师进行评价,符合灰色少数据贫信息的特征,利用灰色关联模型,构建组合赋权法灰色关联职业技术类高校教师绩效评价模型,既保证了评价体系的客观公平性也凸显了科学合理性.最终对江苏旅游职业学院的教师绩效水平进行评价,得出结论并分析原因.     

灰色非线性约束规划的改进引力搜索算法求解

灰色非线性约束规划是灰色系统中一个重要的优化问题.为求解灰色非线性约束规划,给出了一种改进引力搜索算法的求解方法.实验结果表明改进引力搜索算法对求解灰色非线性约束规划可行有效.     

灰色自记忆耦合模型在复杂装备费用测算中的应用

为了全面提高复杂装备费用的合理使用度,构建了复杂装备费用测算的灰色自记忆耦合模型,借助自记忆预测技术来提高其预测精度.模型通过有机耦合自记忆原理与传统灰色模型,综合了两者各自的优势.系统的自记忆方程包含多个时次初始场而不仅是单个时次初始场,从而克服了传统灰色预测模型对初值比较敏感的弱点.通过对复杂装备费用测算的两个案例...     

灰色GM(1,1,

将灰色理论用于人体药物代谢动力学的研究,建立了一种新的灰色模型GM(1,1,     

Models for determining how many natural enemies to release inoculatively in combinations of biological and chemical control with pesticide resistance

Combining biological and chemical control has been an efficient strategy to combat the evolution of pesticide resistance. Continuous releases of natural enemies could reduce the impact of a pesticide on them and the number to be released should be adapted to the development of pesticide resistance. To provide some insights towards this adaptation strategy, we developed a novel pest–natural enemy model considering both resistance development and inoculative releases of natural enemies. Three releasing functions which ensure the extinction of the pest population are proposed and their corresponding threshold conditions obtained. Aiming to eradicate the pest population, an analytic formula for the number of natural enemies to be released was obtained for each of the three different releasing functions, with emphasis on their biological implications. The results can assist in the design of appropriate control strategies and decision-making in pest management.     

The dynamics of pest control pollution model with age structure and time delay

In this paper, by using pollution model and impulsive delay differential equation, we investigate the dynamics of a pest control model with age structure for pest by introducing a constant periodic pesticide input and releasing natural enemies at different fixed moment. We assume only the pests are affected by pesticide. We show that there exists a global attractive pest-extinction periodic solution when the periodic natural enemies release amount μ₁ and pesticide input amount μ₂ are larger than some critical value. Further, the condition for the permanence of the system is also given. By numerical analyses, we also show that constant maturation time delay, pulse pesticide input and pulse releasing of the natural enemies can bring obvious effects on the dynamics of system. We believe that the results will provide reliable tactic basis for the practical pest management.     

Eco-epidemiology model with age structure and prey-dependent consumption for pest management

In this paper, a prey-dependent consumption predator–prey (natural enemy-pest) model with age structure for the predators and infectious disease in the prey, is considered. Infectious pests, immature natural enemies and mature natural enemies are released impulsively. By using Floquet’s theorem, small-amplitude perturbation skills and comparison theorem, we obtain both the sufficient conditions for the global asymptotical stability of the susceptible pest-eradication periodic solution and the permanence of the system. The results provide a reliable theoretical tactics for pest management.     

椰心叶甲虫综合防治脉冲动力学模型的周期解

椰心叶甲虫是棕榈科植物最主要的害虫之一.论文针对两类寄生蜂攻击椰心叶甲虫不同年龄阶段的特点,建立了阶段结构的脉冲定期喷洒药物和释放天敌的综合防治模型.通过重合度理论和分析工具,证明了该模型周期解的存在性,给出了周期解存在的充分条件,并通过数值模拟验证了理论结果的有效性.     

The effects of impulsive releasing methods of natural enemies on pest control and dynamical complexity

In the present paper the different releasing methods including constant releasing and proportional to the predator population are considered and analyzed. The effects of these releasing methods of natural enemies on dynamical behavior are investigated. We firstly take into account the model with an impulsive effect at fixed moments, and the results imply that under some conditions the pest may serve to extinction. Several types of attractors can coexist, with switch-like transitions among their attractors showing that varying dosages and frequencies of insecticide applications and the numbers of natural enemies released are crucial. Secondly, the model with unfixed moments is further investigated. Different periodic solutions also exist and the maximum amplitude of the host is always less than the economic threshold. Comparing the results obtained for the two models concludes that the proportional releasing predator has strong effects on the dynamical behavior.     

Hybrid approach for pest control with impulsive releasing of natural enemies and chemical pesticides: A plant–pest–natural enemy model

The agricultural pests can be controlled effectively by simultaneous use (i.e., hybrid approach) of biological and chemical control methods. Also, many insect natural enemies have two major life stages, immature and mature. According to this biological background, in this paper, we propose a three tropic level plant–pest–natural enemy food chain model with stage structure in natural enemy. Moreover, impulsive releasing of natural enemies and harvesting of pests are also considered. We obtain that the system has two types of periodic solutions: plant–pest-extinction and pest-extinction using stroboscopic maps. The local stability for both periodic solutions is studied using the Floquet theory of the impulsive equation and small amplitude perturbation techniques. The sufficient conditions for the global attractivity of a pest-extinction periodic solution are determined by the comparison technique of impulsive differential equations. We analyze that the global attractivity of a pest-extinction periodic solution and permanence of the system are evidenced by a threshold limit of an impulsive period depending on pulse releasing and harvesting amounts. Finally, numerical simulations are given in support of validation of the theoretical findings.     

An integrated pest management model with delayed responses to pesticide applications and its threshold dynamics

Pulse-like pest management actions such as spraying pesticides and killing a pest instantly and the release of natural enemies at critical times can be modelled with impulsive differential equations. In practice, many pesticides have long-term residual effects and, also, both pest and natural enemy populations may have delayed responses to pesticide applications. In order to evaluate the effects of the duration of the residual effectiveness of pesticides and of delayed responses to pesticides on a pest management strategy, we developed novel mathematical models. These combine piecewise-continuous periodic functions for chemical control with pulse actions for releasing natural enemies in terms of fixed pulse-type actions and unfixed pulse-type actions. For the fixed pulse-type model, the stability threshold conditions for the pest eradication periodic solution and permanence of the model are derived, and the effects of key parameters including killing efficiency rate, decay rate, delayed response rate, number of pesticide applications and number of natural enemy releases on the threshold values are discussed in detail. The results indicate that there exists an optimal releasing period or an optimal number of pesticide applications which maximizes the threshold value. For unfixed pulse-type models, the effects of the killing efficiency rate, decay rate and delayed response rate on the pest outbreak period, and the frequency of control actions are also investigated numerically.     

Effects of population dispersal and impulsive control tactics on pest management

In this paper, we firstly consider a Lotka–Volterra predator–prey model with impulsive constant releasing for natural enemies and a proportion of killing or catching pests at fixed moments, and we have proved that there exists a pest-eradication periodic solution which is globally asymptotically stable. Further, we extend the model for the population to move in a two-patch environment. The effects of population dispersal and impulsive control tactics are investigated, i.e. we chiefly address the question of whether population dispersal is beneficial or detrimental for pest persistence. To do this, some special cases are theoretically investigated and numerical investigations are done for general case. The results indicate that for some ranges of dispersal rates, population dispersal is beneficial to pest control, but for other ranges, it is harmful. These clarify that we can get some new effective pest control strategies by controlling the dispersal rates of pests and natural enemies.     

害虫治理的病毒感染模型

研究了食饵受病毒感染且捕食者具有Beddington-DeAngelis功能性反应的生态流行病模型,此模型考虑的是脉冲释放病毒颗粒和自然天敌. 利用Floquet乘子理论、小振幅扰动技巧和比较定理证明了害虫根除周期解的全局渐近稳定性以及系统持续生存的充分条件.结论为现实的害虫管理提供了有效的策略依据.     

Comment on “Existence and stability of periodic solution of a Lotka-Volterra predator-prey model with state dependent impulsive effects” [J. Comput. Appl. Math. 224 (2009) 544-555]

In this paper, according to integrated pest management principles, a class of Lotka-Volterra predator-prey model with state dependent impulsive effects is presented. In this model, the control strategies by releasing natural enemies and spraying pesticide at different thresholds are considered. The sufficient conditions for the existence and stability of the positive order-1 periodic solution are given by the Poincaré map and the properties of the LambertW function.