应用物元评判识别模型预测农业害虫种群动态

论述了物元评判识别模型的建模方法,并探讨了该模型在预测农业害虫种群动态方面的应用．结果表明,其历史拟合率高达 ９２．３１％,将 １９９５年作为独立样本进行试报,其预报结果与实际发生一致．并指出物元评判模型是预测农业害虫种群动态的一种优良模型．     

麦蚜复合种群动态预测的Fuzzy推理模式及应用

本研究利用了山东省曲阜地区１９８２－１９９４年共１３年的资料，选用了３月下旬至４月上旬平均气温（℃）和４月７上旬温湿系数作为预报因子，麦蚜蚜量始达５００（头／丰株）的日期作为预报对象组建Ｆｕｚｚｙ推理模式。对历史资料进行回代验证，其历史拟合率达１００％。将１９９５年的观测数据作为独立样本进行试报，预测结果与实际一致。为麦蚜复合种群动态预测提供了一种新的研究方法。     

闽北地区四代三化螟发生动态Fuzzy预测模型研究

根据Fuzzy数学原理和三化螟生物学特性,组建了四代三化螟发生动态综合预测模型经对福建省将乐县16年四代三化螟发生期、发生量回报及1995年的预报,拟合率及正确率均达100％。     

害虫种群动态的组合预测

单一的预测模型,由于丢弃了大量有用信息,因而影响预测效果。本文采用组合预测,不仅应用了一种新的统计预报方法;而且通过三化螟发生量预测实例,减少了预测误差,提高了准确度。     

特征展开模糊近似推理法在害虫发生趋势预报中的应用

<正> 害虫发生趋势受作物、天敌和气候等因子的综合影响,故其预报系统是一个复杂的、开放的大系统。大系统的一个显著特点是人参予其中,因人的思维过程具有模糊性这一固有特征,故人能发出、接受和处理模糊信息。对某个问题或专业(如测报)有过多年实践经历的人,头脑中对系统过程往往拥有大量的理性认识,这就是人对事物的经验。这种经验虽带有不同程     

重要经济害虫烟粉虱的发生

烟粉虱Ｂｅｍｉｓｉａｔａｂａｃｉａ(Ｇｅｎｎａｄｉｕｓ)是热带和亚热带地区的主要害虫之一 ,其广泛分布于南美洲、欧洲、非洲、大洋洲和亚洲的 56个国家和地区 ,寄主植物达 74科 50 0余种[1,2 ] 。该虫除直接危害植物 ,导致叶片枯黄脱落外 ,还可分泌蜜露 (诱发煤污病、使棉纤维带有粘性 )、传播病毒。已证明 ,烟粉虱可传播 1 5种病毒 ,引起40多种植物病害[2 ] 。80年代以前 ,烟粉虱主要在美国、前苏联、埃及、印度、巴西、伊朗和土耳其等国的棉花上为害。 80年代以后 ,又发现此虫对也门的西瓜、墨西哥的西红柿、印度的豆类、日本的花卉造…     

数学判别模型在预测害虫种群动态上的应用

根据两个总体的Fisher判别准则,建立了预测害虫种群动态的数学判别模型,对山东省惠民县1967～1977年共11年二代棉铃虫发生程度的两类资料进行了数量分析,建立了数学模型：y＝0．0127x1－0．023X2,对历史资料的回代验证与独立样本的预测,符合率在90％以上。     

黑龙江大兴安岭地区森林害虫发生面积与气象因子的关系

对黑龙江大兴安岭地区6个气象台站的气象资料进行整理和分析,从中筛选出影响虫害发生面积的7个气象因子,并分别对其做相关分析,研究了气象因子对种群数量的影响,模拟虫害发生面积预测方程.结果表明:与虫害发生面积密切相关的因子有年积温(≥10℃)、年降水量和干燥度;虫害发生面积同三者的Pearson相关系数分别为0.701、-0.814和0.937;通过分析极端气候现象对虫害面积的影响,发现春季阴雨和虫害面积存在显著的正相关关系,冬冻和春寒对虫害发生面积并没有直接的影响.     

旱直播水稻主要害虫发生的特点及其防治

通过1986～1988年的调查,旱直播水稻主要害虫的发生特点是:苗期稻蓟马、稻象甲为害突出,后期稻纵卷叶螟发生较重,褐稻虱的发生相对较轻。为了保护旱直播水稻的正常生长和稳产高产,应区别对待,因地制宜地掌握苗情和虫情,适期使用有效农药,开展综合防治。     

害虫预测预报的生态学基础和应用技术研究进展

概述害虫预测预报领域的最新动态,包括理论基础：非线性动力学、景观生态学、生物地理统计学、异质种群和生态系统链接理论,以及应用技术：地碉诱捕、雷达监测、地理信息系统、全球定位系统、遥感、可视化技术和决策支持系统,对于害虫不则报的基础理论研究和害虫管理的生产应用都具有重要的指导意义。     

一种天敌控制多种害虫作用的模糊数学评价方法

从生物防治的基本思想出发,利用模糊数学和生态经济的原理,探讨天敌的作用,建立了一种天敌控制多种害虫的模糊数学评判方法,文中给出了一种天敌对害虫的影响率和影响强度、一种天敌对害虫影响的大小以及天敌对害虫的控制能力,并进行了控制分析。     

生态控制茶园内害虫、天敌种类及数量的季节变化规律

对衡山生态控制茶园内害虫,天敌种类及数量季节变化的系统调查与排序分析表明,生态控制茶园由于生态环境优良,长期不使用化学农药,使得害虫,天敌种类多,数量少,群落间处于较好的平衡状态,群落的季节变化明显受到气候条件、茶树生育期和茶园采摘的影响,害虫、天敌的年消长规律与茶树的生长规律基本相同,即每年的11月份至翌年的3月份为茶树,害虫与天敌的越冬期;5至9月份为活动高峰期,茶树旺盛生长,害虫,天敌大量繁衍活动;4和10月份是过渡期,茶树,害虫与天敌均由越冬转入活动或由活动转入越冬,体现了天敌－害虫－茶树之间的追随与平衡状态,根据各个时期群落的特点可以采取相应的综合治理措施,因此,改善茶园生态环境,加强茶园管理,减少化学农药的使用是茶园害虫生态控制的基础和保护。     

多种天敌控制多种害虫的模糊数学模型

从生态经济学的原理出发，利用模糊集理论，探讨如何评价天敌控制多种害虫的为害作用，提出了多种天敌控制多种害虫的模糊数学模型。同时又得到了天敌对害虫的控制能力C，影响率G，影响强度H，及权数ω(x)的计算公式，以及在天敌作用下安全度的讨论与分析。     

A Mathematical Model of Uterine Dynamics and its Application to Human Parturition

We have developed a simple mathematical model with three physiologically significant states to describe the changes in intrauterine pressure associated with a contraction during human parturition. The myometrium is modelled as a set of smooth muscle cells, each of which is in one of three states (quiescent, contracted, refractory) at a given time. These states are occupied according to a cycle governed by three temporal parameters. The solutions of the equations describing the model show an oscillatory behavior for particular values of these parameters, which is very similar to the time dependant development of intrauterine pressure during labor. Due to its non-linear terms, our model could lead to chaotic oscillations (in the mathematical sense), whose clinical counterpart may occur in cases of dystocia. Despite its simplicity, this model appears to be a useful guide to further investigations of the oscillatory behavior of the myometrium, or other smooth muscles, in normal and pathological situations.     

A Model for Multi-site Pacing of Fibrillation Using Nonlinear Dynamics Feedback

Traditionally, cardiac defibrillation requires a strong electric shock. Many unwanted side effects of this shock could be eliminated if defibrillation were performed using weak stimuli applied to several locations throughout the heart. Such multi-site pacing algorithms have been shown to defibrillate both experimentally (Pak et al., Am J Physiol 285:H2704–H2711, 2003) and theoretically (Puwal and Roth, J Biol Systems 14:101–112, 2006). Gauthier et al. (Chaos, 12:952–961, 2002) proposed a method to pace the heart using an algorithm based on nonlinear dynamics feedback applied through a single electrode. Our study applies a related but simpler algorithm, which essentially configures each electrode as a demand pacemaker, to simulate the multi-site pacing of fibrillating cardiac tissue. We use the numerical model developed by Fenton et al. (Chaos, 12:852–892, 2002) as the reaction term in a reaction–diffusion equation that we solve over a two-dimensional sheet of tissue. The defibrillation rate after pacing for 3 s is about 30%, which is significantly higher than the spontaneous defibrillation rate and is higher than observed in previous experimental and theoretical studies. Tuning the algorithm period can increase this rate to 45%. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

A Stochastic Population Dynamics Model for Aedes Aegypti: Formulation and Application to a City with Temperate Climate

Aedes aegypti is the main vector for dengue and urban yellow fever. It is extended around the world not only in the tropical regions but also beyond them, reaching temperate climates. Because of its importance as a vector of deadly diseases, the significance of its distribution in urban areas and the possibility of breeding in laboratory facilities, Aedes aegypti is one of the best-known mosquitoes. In this work the biology of Aedes aegypti is incorporated into the framework of a stochastic population dynamics model able to handle seasonal and total extinction as well as endemic situations. The model incorporates explicitly the dependence with temperature. The ecological parameters of the model are tuned to the present populations of Aedes aegypti in Buenos Aires city, which is at the border of the present day geographical distribution in South America. Temperature thresholds for the mosquito survival are computed as a function of average yearly temperature and seasonal variation as well as breeding site availability. The stochastic analysis suggests that the southern limit of Aedes aegypti distribution in South America is close to the 15^∘C average yearly isotherm, which accounts for the historical and current distribution better than the traditional criterion of the winter (July) 10°C isotherm.     

一类灰色项时间序列模型及其应用

利用灰色系统理论与时间序列分析,提出了带灰色项的时间序列模型,对这类模型进行了分析,给出了建模与预报方法,并将其应用于我国农业产值问题的预报与研究之中,模型的正确性得到了检验．