基于LuGre摩擦模型的轮胎自振系统数值分析

为用多边形磨损理论研究汽车轮胎磨损,针对最简化的单自由度胎面-路面非线性系统,单独分析胎面侧向自激振动特性与车速的关系. 将LuGre摩擦模型引入胎面-路面单自由度振动系统,模拟轮胎与路面的实际摩擦情况. 利用Matlab仿真胎面在不同车速条件下的振动情况. 结果表明在一定的系统参数设置下,胎面在轮胎宽度方向上能产生硬自激,且车速范围与已知情况基本吻合,从而证明该理论模型正确.     

基于有限元的轮胎自激振动时频分析

研究汽车轮胎减少磨损,延长使用寿命的问题,轮胎多边形磨损与胎面质量块的侧向自激振动密切相关.了解产生自激振动的速度区间以及胎面与地面的摩擦状态就显得十分重要.因此建立了轮胎一地面系统的理论模型,引入符合轮胎橡胶摩擦规律的摩擦曲线.运用有限元软件,建立子轮胎与地面有限元模型,导入上述摩擦曲线,分析了位移时间历程和位移速度相平面图,发现了容易产生自激振动的速度区间.选择三种特征车速进行仿真.结果证明通过研究可以减少轮胎的磨损量,延长寿命,为今后轮胎多边形磨损正确建模有参考价值.     

胎面纠偏控制系统中图像处理技术的应用

介绍了实时胎面纠偏系统的原理和结构.整个系统主要由控制器、控制对象、图像采集和图像处理单元组成,重点对图像处理单元进行研究.根据对胎面图像特点进行的分析,提出了图像处理单元的实现过程和算法分析,包括图像去噪,阈值分割,边缘检测和特征提取,计算偏移角.从提取出的胎面骨架实验结果来看,提取效果比较理想.     

基于图像处理的胎面纠偏控制系统

轮胎生产过程中广泛采用纠偏系统防止半成品胶带发生跑偏。纠偏系统是一个实时或准实时的系统,其性能的好坏主要取决于图像处理模块。本文为了更好地保留图像信息,减少噪声对图像的影响,首先利用小波包对图像的低频和高频部分进行分解;然后,采用Birge-Massart惩罚函数确定的阈值对胎面图像进行有效去噪;接着,利用Robert算子进行边缘检测,提取出胎面边缘和机架边缘;最后,经过算法计算出胎面的偏移角度。     

基于压力和位移传感器的汽车节胎系统

针对大吨位的运输车辆(特别是半挂车)轮胎磨损严重,空载时造成轮胎无谓磨损及耗油等问题,介绍了基于压力和位移双传感器汽车智能节胎系统,通过机电一体化智能节胎的新方法,可以自适应调节汽车在重载时挂车三桥12轮工作,而当空载时挂车均为单桥4轮工作。从而减少了约30%的轮胎磨损,实现节胎、节能、延长车辆的使用寿命和保证安全行车目的。     

汽车轮胎号识别中的图像采集

图像采集是汽车胎号识别中的一个首要和重要的环节,介绍了胎号图像采集过程,胎号图像采集中的辅助光源和摄像硬件装置,以及用于调焦、调亮的镜头控制器的设计,最后编程实现胎号图像采集,并将其进行灰度化处理。     

基于机器视觉的轮胎表面缺陷检测系统的研究与应用

在传统的轮胎表面缺陷依靠人工检测,存在劳动强度高、受人的主观影响大以及效率低下的问题。针对这一现象,研究了一种基于机器视觉的轮胎表面缺陷3D检测系统。该系统依靠机器视觉系统获取检测轮胎的表面图像,然后创建3D模型、判定缺陷类型,最终实现实时自动预警,为轮胎生产商提供一种自动化检测方案。系统集成了先进的技术、软件和工具,配套的信息管控系统可以对轮胎型号和生产数据进行采集、存储、分析,以便在生产过程中实现更高效、更可靠的质量控制,具有较高的实际应用推广价值。     

基于B样条曲线的轮胎胎面缠绕算法

为了提高胎面缠绕生产线设备的缠绕质量以及胶条分布的稳定性,降低研发成本和废品率。通过研究工程机械轮胎胎面缠绕机缠绕时胶条的具体缠绕过程,基于B样条曲线理论,提出了胶条缠绕轮胎截面变化情况的算法,对当前的轮胎胎面缠绕过程进行精确的数学描述,实现了对轮胎胎面缠绕过程中轮胎胎面与胶条形状位置的精确控制。实验结果表明:所提方法可以有效提高轮胎胎面缠绕精度,可见所提方法能够增强轮胎生产工艺修改适用性、精确性和稳定性。     

基于NURBS曲线的轮胎胎面缠绕仿真算法

针对计算开环控制的胎面缠绕生产系统中配置的胎面缠绕系统算法性能差的问题, 本文提出了一种基于NURBS曲线的胎面缠绕仿真算法并进行了实例验证. 目前轮胎胎面缠绕开环控制系统配置的胎面缠绕仿真软件多使用直线与圆弧对缠绕过程中的曲线进行仿形, 软件内置算法存在缠绕出的胎面与理想胎面偏差较大且缠绕效率低的问题, 故本文改用NURBS曲线对缠绕过程中的曲线仿形, 提出了一种基于NURBS曲线的轮胎胎面缠绕仿真算法. 实例验证结果表明, 所设计的胎面缠绕仿真算法缠绕的胎面形状符合国家标准和企业要求, 具有一致性好, 生产效率高等优点.     

基于小波的人体图像边缘检测的研究及实现

针对人体图像边缘检测的问题,本文从工程应用的角度上分析小波变换的原理,利用Mallat方法对图像信息进行处理.通过C 编程,来实现人体图像的边缘检测.     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate