双车道公路弯道回旋线长度对行车特性的影响

基于驾驶模拟实验,采集了15名驾驶员在半径为100～500 m的72个弯道路段的车速、侧向偏移等数据,研究双车道公路弯道路段回旋线长度对车速及行车轨迹的影响.结果表明:在半径一定的条件下,随着回旋线长度增加,前后路段车速差呈上升趋势,而速度梯度随之下降;行车轨迹波动幅度随回旋线长度增加而增大,而波动频率随之降低;半径为...     

关于G/G/1排队模型中排队长度的积分

考虑了一个具有中度正则变化服务时间的G/G/1模型.假设Q(t)是排队长度,则在忙期[0,l]上,Q(t)下方所扫过的面积也具有中度正则变化的性质.     

A NAM Representation Method for Data Compression of Binary Images

A representation method using the non-symmetry and anti-packing model (NAM) for data compression of binary images is presented.The NAM representation algorithm is compared with the popular linear quadtree and run length encoding algorithms.Theoretical and experimental results show that the algorithm has a higher compression ratio for both lossy and lossless cases of binary images and better reconstructed quality for the lossy case.     

弧长公式成立的充要条件

连续曲线不一定可求长，连续曲线可求长当且仅当它的参数表示是有界变差的，但弧长未必能用公式表达，利用勒贝格积分的基本理论证明绝对连续是弧长可用公式计算的充要条件。     

须丛曲线理论研究

提出了一种测量纤维长度的新制样方法——纤维条梳夹取样法,理论研究了以此法制取试样(即须丛)的纤维长度分布规律,建立了须丛曲线(纤维根数随长度变化规律)理论方程,获得了原样品长度质量分布与须丛曲线的数学关系,并推导出由须丛曲线计算原样品长度质量分布参数(平均长度、主体长度、品质长度、变异系数)的计算公式.     

教师资源配置合理性分析与对策研究

阐述了教师资源合理配置的重要性,分析了教师资源配置不合理的表现,探讨了城乡教师资源配置均衡化的对策。     

The atyid shrimp (Crustacea: Decapoda: Atyidae) rostrum: phylogeny versus adaptation,taxonomy versus trophic ecology

Cave shrimps of the subgenus Troglocaris (Atyidae), exhibit high variability in rostral length and dentition. In shrimp populations that co-occur with the amphibian predator Proteus anguinus, longer rostra armed with more numerous teeth are recorded. These shrimps are also larger than those living in a presumably Proteus-free environment. Discrepancies between molecularly established phylogenetic relationships and distributions of rostral length, as well as body size, directed our search towards possible environmental influences. These discrepancies suggest that rostral shape is not a reliable taxonomic character in some generic and many specific diagnoses in Atyidae. We discuss some taxonomic consequences of sexual and ontogenetic rostral differences with regard to the molecular phylogenetic tree. In preliminary laboratory observations, no frontal attack by Proteus was successful on shrimps with long rostra. Proteus also needed more time to swallow shrimps with long rostra.     

一种可视队列随机网络仿真语言-VIML

可视编程语言是近几年讨论的热门话题，它正在渗透各科学技术领域。本文介绍一种可视队列随机网络仿真语言，讨论了这种语言的结构及实施的技术问题     

起停式角钢飞剪控制系统

作者根据起停式角钢飞剪的剪切工艺要求,研制出一种新型的起停式飞剪的直流控制系统。该系统能够逻辑控制剪刃的运行规律,保证剪刃线速度与轧件线速度同步,保证剪切产品长度的定尺精度。本文介绍这种新型的起停式角钢飞剪直流控制系统的结构及控制思想,重点论述了保证同步及定尺精度的措施。