二手车鉴定评估软件在教学中的应用

本文通过二手车鉴定评估教学软件的介绍,针对目前本课程教学内容单一,教学设备紧缺的情况,分析了软件在理论教学和实践教学中所起的积极作用,同时阐述了利用软件教学能大大提高了学生学习的主动性。     

交流传动系统三电平逆变器的实时仿真

本文对二极管箝位型三电平逆变器进行研究，分析了逆变器的电流电压关系和死区效应，利用开关函数建立了逆变器电压及电流的Simulink实时模型，给咄了基于dSPACE实时仿真环境的逆变器一异步电机实时仿真系统的实现方法。试验结果验证了模型和仿真方法的正确性。     

Variations in household transport expenditure within major Australian cities

A comparative analysis of intra‐urban variations in household transport expenditure in 1966–68 is undertaken for the two largest Australian cities, Sydney and Melbourne, and one of the smaller State capitals, Adelaide. Regional variations in transport expenditure are found to be greater the larger the city; however residents of small cities are more dependent upon the car for their motorised travel. In the larger cities car dependence is most evident among low‐to‐middle income groups at a relatively early stage in the life cycle, located in outer suburban areas. Consequently high levels of expenditure on transport typically coincide with relatively high levels of financial commitments to home purchase and/or operation. This has significant ramifications for the household budget, the most notable being deficit‐funding, and reduced outlays on other expenditure items such as recreation and education. The distribution of company vehicles and allowances is shown to be of relatively greater benefit to higher income groups, although is not confined to them. Although somewhat dated, the findings suggest that the social impacts of rising prices for energy will almost certainly be regressive.

Note: This paper was presented to the 7th PTRC Summer Annual Meeting held at the University of Warwick in July 1979. The authors gratefully acknowledge the contribution of the Australian Road Research Board in the preparation of the paper. Particular appreciation is expressed to Dr. M. R. Wigan, Mr. K. Sharp and Dr. M. G. Lay for their helpful comments.     

柴油-LNG内河散货船风险识别研究

文中在介绍危险识别的方法基础上，经过对柴油-LNG双燃料发动机改装船舶的系统综合分析，识别出各类潜在危险可能对船舶因改装为柴油-LNG双燃料船舶后所构成的安全威胁，运用故障树和事件树方法分别分析LNG储气罐和机舱火灾的风险后果，得出减少事故发生的措施     

加工过程中假废品成因与判识方法研究

结合机械零件的加工过程,从测量基准与设计基准不重合和定位基准与设计基准不重合2方面界定了假废品的科学含义.探讨了产生假废品的主要原因,分析了加工中工艺基准与设计基准不重合时,用极值法换算工序尺寸的方法及各组成环误差之间的补偿规律.基于工艺尺寸链理论,确定了合格品、假废品、废品在零件公差带上的分布区域,提出了假废品的判识...     

特征量对某交通流混沌实时判定系统的影响

为分析特征量对该系统判定结果的影响,以交通流微观仿真软件产生的交通流为对象进行了实验研究,讨论了在相同条件下,不同的特征量(功率谱、小波包系数、小波包能量)对此系统判定结果的影响.实验结果表明,特征量对该系统判定结果影响较大,选用基于小波包能量的特征提取判定效果更好.     

基于衰减因子的时变增益KALMAN滤波

常用的卡尔曼滤波器(KF,EKF)一般只适用于平稳的状态过程,当目标处于变化不大的过程时,目标状态突然变化时,KF和EKF将产生较大的估计偏差,甚至丢失目标.文中根据正交性原理,采用时变衰减因子,使得残差达到正交或近似正交,从而使滤波器在不确定模型下保持较好的鲁棒性.通过实时调节增益,促使测量残差近似正交,从而提高对机动目标的跟踪性能.仿真实验表明,应用该方法可以快速、稳定地完成目标运动要素的估计.     

钢结构安全鉴定与加固技术的探讨

针对当前许多钢结构建筑老化的现状,文章阐述了钢结构的加固程序和加固方法,并结合具体实例对钢结构的加固进行了探讨和研究,对当前钢结构建筑的加固具有一定的借鉴价值。     

基于CT技术沥青混合料集料的识别与分离

为了研究沥青混合料内部集料结构,利用CT断层扫描技术对沥青混合料内部集料进行三维重构,基于Matlab自行编制程序对集料进行识别与分离.很多情况下集料是互相接触的,这些相互接触的集料容易被程序错误地识别成是一个集料.为此首先用Gaussian过滤器使集料变得更光滑,再利用Hmax过滤器使集料变得更平滑,最后进行Wat...