8p阶群的类方程及其对群结构的影响

利用群的相关理论得到8p阶群G的类方程并且刻画了G的结构,通过类方程研究了其共轭类图的性质,利用这个结果讨论了连通分支数满足一定条件时关于G的结构.     

杉松人工林伐区调查设计中树高曲线图的绘制与应用

为提高罗源县杉、松人工林树高曲线图绘制的准确性,利用广泛拟合择优选取的方法确定了能很好描述罗源县杉、松人工林胸径(D)树高(H)的一元二次函数模型,同时利用Excel电子表格设计绘制树高曲线图的程序。研究结果具有较大的应用价值。     

Characterizing the importance of habitat patches and corridors in maintaining the landscape connectivity of a Pholidoptera transsylvanica (Orthoptera) metapopulation

Since the fragmentation of natural habitats is one of the most serious problems for many endangered species, it is highly interesting to study the properties of fragmented landscapes. As a basic property, landscape connectivity and its effects on various ecological processes are frequently in focus. First, we discuss the relevance of some graph properties in quantifying connectivity. Then, we propose a method how to quantify the relative importance of habitat patches and corridors in maintaining landscape connectivity. Our combined index explicitly considers pure topological properties and topographical measures, like the quality of both patches (local population size) and corridors (permeability). Finally, for illustration, we analyze the landscape graph of the endangered, brachypterous bush-cricket Pholidoptera transsylvanica. The landscape contains 11 patches and 13 corridors and is situated on the Aggtelek Karst, NE-Hungary. We characterize the importance of each node and link of the graph by local and global network indices. We show how different measures of connectivity may suggest different conservation preferences. We conclude, accordingly to our present index, by identifying one specific habitat patch and one specific corridor being in the most critical positions in maintaining connectivity.This revised version was published online in May 2005 with corrections to the Cover Date.     

变冲击系数的几何参数化变矩器特性模

为解决变矩器特性模型中因冲击损失造成理论预测误差偏大的问题,建立了变冲击损失系数的几何参数化变矩器特性模型.模型以键合图作为系统动力学工具,采用模块化建模方法,分析了各工作轮的工作特性与能量损失,实现了通过几何参数进行工作特性的预测,采用变冲击损失系数的方法来增加模型精度.与样机性能实验结果对比表明,在转速比0至1全区段内,变冲击损失系数方法得出的变矩比和效率百分比误差的波动变化更小,这说明在工况复杂的情况下采用变冲击损失系数方法有一定优势.     

基于分形维数和HHT的蚜虫刺吸电位波形机器识别

昆虫刺吸电位(electricalpenetrationgraph,EPG)技术在研究刺吸式昆虫取食行为、昆虫与植物的关系、昆虫传毒机制、作物抗虫机制等方面得到了广泛的应用,然而EPG信号的识别和分析一直是靠人工进行,亟需波形自动识别系统以提高分析效率。刺吸式昆虫取食植物时,产生的EPG波形跟昆虫和植物的种类有关,不同类别的刺吸式昆虫EPG波形差别很大,即使是同种类型的EPG波形其幅值和频率间也会有差异,这给EPG波形的机器识别带来了困难。该文以蚜虫的EPG信号为研究对象,对np波、pd波、E1波、E2波、G波、C波和F波的特征提取和分类识别进行了研究,提出了一种基于分形维数、希尔伯特-黄变换(hilbert-huang transform,HHT)和决策树的EPG波形识别方法。首先对EPG仪器采集得到的信号进行去噪预处理,分别提取分形维数和HHT共10维特征,组成不同维数的特征向量进入决策树分类器进行对比试验。试验结果表明,可采用分形盒维数、Hurst指数、前2层的谱质心和加权频率融合的6维特征向量获得较高的识别率。在EPG波形的机器识别中采用6维特征向量输入的决策树进行分类,通过对4组不同样本进行测试,得到了92.14%、89.29%、95%和89.29%的识别率,平均识别率为91.43%。研究结果表明该文提出的基于分形维数和HHT的特征提取方法以及构建的决策树分类器具有一定的可行性,可为研发EPG信号自动识别分析系统提供理论参考。     

窑窖滴灌系统输水管路的优化布置

窑窖集雨滴灌成为解决我国干旱半干旱地区水资源短缺的途径之一。该文分析了窑窖分散式水源特点：水量较小，零星分布，管道设计困难，系统管理繁杂。以在农作物缺水关键期进行灌溉为出发点，根据水窖和地块分散的特点，通过对水窖输水线路优化设计，降低灌溉的管理和工程造价，设计最佳滴灌输水路线，达到水源联合调度的目的，并与传统设计方法和图论优化设计法进行了比较。所提出的设计方法适合解决各种地形条件下分布水源的输水路线布置问题。     

柑橘衰退病毒株对两种橘蚜不同翅型取食行为的影响

为明确感染柑橘衰退病毒(Citrus tristeza virus,CTV)的柑橘对不同翅型橘蚜取食行为的影响,通过刺探电位图谱技术(electrical penetration graph,EPG)对褐色橘蚜和棉蚜在感染CTV植株上的取食行为进行持续记录,与健康植株进行比较分析。结果表明,褐色橘蚜无翅型在感病植株的参数均与有翅型无显著差异;棉蚜无翅型在感病植株上的非刺探波(no penetration,np波)和路径波(C波)的总持续时间、电势落差(potential drops,pd波)的次数均显著小于有翅型,C波和刺探的次数均极显著小于棉蚜有翅型。褐色橘蚜无翅型在感病植株上的pd波的次数和韧皮部分泌唾液波(E1波)的平均持续时间显著小于棉蚜无翅型;褐色橘蚜有翅型在感病植株上的C波的次数和总持续时间、刺探的次数、pd波的次数和总持续时间均极显著小于棉蚜有翅型,韧皮部被动吸食波(E2波)的总持续时间和平均持续时间均极显著大于棉蚜有翅型。褐色橘蚜无翅型在感病植株上的刺探和pd波的次数均显著高于健康植株,但总刺探时间相反,np波、C波和非韧皮部阶段的总持续时间极显著高于健康植株,E2波的总持续时间极显著短于健康植株。表明柑橘感病状态对无翅型和有翅型的影响是相似的;柑橘感染CTV对褐色橘蚜无翅型的取食行为影响明显,且偏好健康植株,从而促进病毒的传播。     

基于梅尔谱图和改进ResNet34模型的鸭蛋裂纹识别算法

针对鸭蛋裂纹人工检测受主观性影响造成精度波动大等问题,利用ResNet34网络模型,提出1种基于梅尔谱图的鸭蛋裂纹识别算法。首先利用敲蛋装置收集敲蛋声音数据,再将音频转化成梅尔谱图,构建梅尔谱图数据集,然后搭建ResNet34模型,引入迁移学习机制训练模型,再通过Adam优化算法更新梯度,增加注意力机制模块并将卷积结构替换为深度可分离卷积以对网络模型进行改进,并调整参数进行优化,最后利用模型对鸭蛋裂纹进行识别。结果显示：改进的ResNet34DP＿CA网络模型检测的平均准确率为92.4%,对比原始ResNet34网络模型,平均准确率提高5.5个百分点,参数量减少32%;对比其他网络模型VGG16、MobileNetv2和EfficientNet,平均准确率分别提高10.9、13.7、16.3个百分点,识别时间为21.5 ms。结果表明,所提出的基于梅尔谱图和改进ResNet34模型的鸭蛋裂纹识别算法,能够有效地对鸭蛋裂纹进行检测识别。     

基于加权Voronoi图的乡镇行政边界调整研究——以山东省商河县为例

以GIS为技术手段,通过综合应用基于GIS的Voronoi图分析方法和多层面复合等空间分析方法,得出了合理的商河县乡镇行政区划调整理论方案。     

Carabids (Coleoptera: Carabidae) in a forest patchwork: a connectivity analysis of the Bereg Plain landscape graph

For many species, one important key to persistence is maintaining connectivity among local populations that allow for dispersal and gene flow. This is probably true for carabid species (Coleoptera:Carabidae) living in the fragmented forests of the Bereg Plain (NE Hungary and W Ukraine). Based on field data, we have drafted a landscape graph of the area representing the habitat network of these species. Graph nodes and links represented two kinds of landscape elements: habitat (forest) patches and corridors, respectively. The quality of habitat patches and corridors were ranked (from low (1) to high (4)), reflecting local population sizes in the case of patches and estimated permeability in the case of corridors. We analysed (1) the positional importance of landscape elements in maintaining the connectivity of the intact network, (2) the effect of inserting hypothetical corridors into the network, (3) the effects of improving the quality of the existing corridors, and (4) how to connect every patch in a cost-effective way. Our results set quantitative priorities for conservation practice by identifying important corridors: what to protect, what to build and what to improve. Several network analytical techniques were used to account for the directed (source-sink) and highly fragmented nature of the landscape graph. We provide conservation priority ranks for the landscape elements and discuss the conditions for the use of particular network indices. Our study could be of extreme relevance, since a new highway is being planned through the area.