有关CAN FD的评论

CAN FD是CAN总线的升级换代设计,它继承了CAN总线的主要特性,CAN FD1．1版增加了可变速的传送方式、更长的数据域长度、新的CRC校验办法等。但是,若接收节点在读帧长时有局部错,接收节点会以低速读取发送帧的高速传送部分,因此可能读不到高速位流中的显位,从而读为EOF正常结束。这种残缺的帧被接收下来,成为新的错帧漏检。CAN FD对CAN总线原有的等效离线故障未加处理。所有这些都会影响到CAN FD在安全攸关系统中的应用。     

基于CAN总线的位定方法的优化研究

CAN总线中,如果位定有一点小错误就会导致总线性能严重下降.尽管位同步有时候会修补由于位定设置不当而产生的错误,但不能完全避免出错情况,并且在遇到两个或多个CAN节点同时发送的情况时,错误的采样点会使节点启动错误认可标志,使节点不能赢得总线上的任何活动.因此针对上面容易发生的错误,对CAN总线位定中的位同步和CAN节点的工作过程进行了深入的分析,并对CAN总线位同步的运行规则以及如何对位定参数设置进行了研究.     

车载CAN总线脱离攻击及其入侵检测算法

CAN总线脱离攻击作为一种新型的攻击方式,通过CAN总线通信的错误处理机制,可以使节点不断产生通信错误并从CAN总线上脱离。针对上述攻击所引发的车载CAN总线通信安全问题,提出了一种车载CAN总线脱离攻击入侵检测算法。首先,总结了车载CAN总线脱离攻击发生的条件与特点,指出正常报文与恶意报文的同步发送是实现总线脱离攻击的难点,并利用前置报文满足同步发送的条件来实现总线脱离攻击。其次,提取了CAN总线脱离攻击的特征,通过累计错误帧的发送数量,并根据报文发送频率的变化实现了对CAN总线脱离攻击的检测。最后,利用基于STM32F407ZGT6的CAN通信节点模拟车内电子控制单元（ECU）,实现了恶意报文和被攻击报文的同步发送。进行了CAN总线脱离攻击实验和入侵检测算法的验证。实验结果表明,检测算法对高优先级恶意报文的检测率在95%以上,因此可以有效保护车载CAN总线通信网络的安全。     

车载CAN总线脱离攻击及其入侵检测算法

CAN总线脱离攻击作为一种新型的攻击方式，通过CAN总线通信的错误处理机制，可以使节点不断产生通信错误并从CAN总线上脱离。针对上述攻击所引发的车载CAN总线通信安全问题，提出了一种车载CAN总线脱离攻击入侵检测算法。首先，总结了车载CAN总线脱离攻击发生的条件与特点，指出正常报文与恶意报文的同步发送是实现总线脱离攻击的难点，并利用前置报文满足同步发送的条件来实现总线脱离攻击。其次，提取了CAN总线脱离攻击的特征，通过累计错误帧的发送数量，并根据报文发送频率的变化实现了对CAN总线脱离攻击的检测。最后，利用基于STM32F407ZGT6的CAN通信节点模拟车内电子控制单元（ECU），实现了恶意报文和被攻击报文的同步发送。进行了CAN总线脱离攻击实验和入侵检测算法的验证。实验结果表明，检测算法对高优先级恶意报文的检测率在95%以上，因此可以有效保护车载CAN总线通信网络的安全。     

基于TTCAN协议的井下通信网络研究

针对煤矿井下CAN通信网络中低优先级数据延迟较大而存在实时性与确定性较差的问题,提出了一种基于时间触发机制的TTCAN协议;给出了由主站节点和多个从站节点构成的TTCAN网络系统硬件结构,详细介绍了基于Level 1同步方式的TTCAN调度算法的设计。实验结果表明,与标准的CAN网络相比,TTCAN网络的最大响应时间和最大发送周期抖动指标几乎不受信息量的增加与优先级减小的影响,具有更好的实时性与确定性。     

基于ISO15765协议的嵌入式系统升级

CAN分布式系统内节点应用软件升级代价高,针对此进行了研究,论述一种将ISO15765协议诊断服务功能运用于CAN总线之上,利用具有Cortex-M3内核的节点微控制器STM32F103VET6集成功能模块和在线应用编程技术(In Application Programming,IAP)。研究实现了嵌入式软件在线升级方案,实验证明该方案操作便捷,可靠性和稳定性好,对其他运用在无线网络中的嵌入式应用软件远程升级有参考意义。     

矿用新能源电机车CAN通信网络软件优化方法

针对矿用新能源电机车CAN节点发送错误造成关键信息丢失的隐患,在TTCAN协议的基础上提出了CAN总线发送容错方法,即对CAN节点发送失败的报文重新发送,当发送成功或者达到预设的最大重发次数后退出该报文的发送;给出了一种CAN总线高效接收、处理报文方法,在中断接收报文期间对报文进行缓存操作,同时修改接收到的报文数量,主程序以此为依据逐条对存放在缓冲区的报文进行后续处理,实现了报文接收与处理的分时操作。测试结果表明,该优化方法可有效提高CAN总线通信的实时性和可靠性,同时减小了各CAN节点CPU开销,提高了工作效率。     

车辆通用故障诊断协议的研究与开发

介绍通用诊断协议ISO14229和基于CAN总线的车辆故障诊断协议ISO15765,分析两者之间的关系及ISO15765的体系结构,在此基础上给出ISO15765协议栈总体设计,并描述协议每一层的软件实现。协议栈设计利用分层接口方式,下层向上层提供服务,协议内部功能采用模块化设计。实验结果表明,该协议栈能满足ISO15765规定的标准和一般的故障诊断功能需求。     

车载诊断系统OBDⅡ的汽车接口数据处理技术

通过车载诊断系统(OBD)连接汽车的CAN总线,进行车辆数据实时采集,同时将采集到的数据进行处理.本文采用TDA61芯片和WiFi无线传输单元搭建两个模块电路,一路发送汽车状态信息,另一路接收所有CAN总线上传输的数据信息.该系统扩展了车载诊断系统的外部应用,应用的汽车协议为支持OBD II的CAN总线的ISO15765协议,收发的数据通过外接串口显示.结果显示,系统实现了汽车接口数据的采集和处理.     

基于TMS320F2812的CAN总线通信的设计与实现

TMS320F2812是一种用于控制的32位定点DSP芯片，对其增强型控制器eCAN的增强特性进行了分析。重点介绍了CAN总线通信中利用eCAN构建CAN网络的硬件节点设计，并给出了CAN总线波特率位定时计算方法，CAN软件设计的流程和对应的C语言初始化，发送接收调试程序，总结了在实际项目应用中的调试技巧。这一设计基于电动汽车，已成功应用于混合动力汽车能量总成控制系统。     

Evaluation of whole-body vibration exposure experienced by operators of a compact wheel loader according to ISO 2631-1:1997 and ISO 2631-5:2004

Limited studies were carried out to evaluate the whole-body vibration (WBV) exposure experienced by operators of compact wheel loaders (CWLs) according to ISO 2631-1:1997. No study was carried out according to ISO 2631-5:2004. Therefore, evaluation of the WBV exposure using these two standards was carried out and the results were compared in this study. Tri-axial accelerations were measured at the seat/operator interface on a medium-sized CWL. The vibration measurements were carried out in ten different operations, such as the V-cycle and the driving over different road surfaces. In order to represent the daily work of the CWL, seven scenarios were proposed. These scenarios are comprised of V-cycle and driving over different distances. The evaluation result according to ISO 2631-1:1997 showed that the permitted daily exposure durations of six scenarios estimated using the vibration dose value (VDV) method did not exceed 8 h. For the pure V-cycle and the combination of V-cycle and slow driving, the permitted daily exposure durations estimated according to ISO 2631-1:1997 were shorter than those estimated according to ISO 2631-5:2004. However, for the combination of V-cycle and fast driving, the permitted daily exposure durations estimated according to ISO 2631-1:1997 were longer than those estimated according to ISO 2631-5:2004.Relevance to industryThis study evaluated the effect of WBV arising from a CWL on human health according to ISO 2631-1:1997 and ISO 2631-5:2004. Evaluation results show that boundaries of the health guidance caution zone in ISO 2631-5:2004 are higher than those in ISO 2631-1:1997.     

基于多进制搜索的RFID防碰撞算法

多标签碰撞问题严重影响射频识别系统的识别效率.确定性树形算法作为一种主流的RFID防碰撞算法可以确保读写器正确识别其工作范围内的标签.为了克服现有树形算法的不足,提出了一种标签ID比特编码机制的多进制搜索(QAS)算法.在算法的设计中引入了标签ID比特编码机制,通过这种编码机制读写器可以实现多比特碰撞仲裁,从而减少碰撞时隙,提高识别效率.理论分析和仿真结果表明.QAS算法降低了标签识别过程中的时间复杂度和通信负载,同参考算法相比具有良好的性能.     

结合ISO 9000品质管理系统与PZB缺口模式以达成顾客满意目标之整合方法

The aim of this study is to combine the designed structure of ISO 9001:2000 QMS and the analysis flow of PZB Gap Model. Related requirements of ISO 9001:2000 QMS were "build-in" into the five gaps of the PZB Gap Model, during 3 phases, for the achievement of service quality. In phase 1, to identify Gaps by using PZB Gap Model as an analysis tool; In phase 2, we fill Gaps by applying ISO 9001:2000 clauses requirements; In phase 3, action are taken to close or narrow Gaps by developing SOP which can be followed by employees in accordance with ISO requirements suggested in phase 2. The integrated model and 3-phase transformation could be utilized as an effective and efficient tool to achieve customer satisfaction objective. It can not only to help both the manufacturing and service industries to satisfy or exceed the ultimate customer needs, but also to improve the processes among enterprises' whole quality management system. To verify our suggested model, we helped a university's Extension Education Training Center in Taiwan to establish its ISO quality management system. A Quality Manual and some ISO procedures were assigned to improve related "Gap" which designed in accordance with our integrated model. From the help of such an ISO and PZB combined philosophy, not only its efficiency improved, the higher trainee satisfaction was also reached.     

A compression-gathering technique for improving the performance of ISO 11898 networks

ISO 11898 (CAN) networks suffer from serious limitations on both the maximum network extension and the allowable bit rate because of the particular arbitration technique they adopt.

In this paper, a modification of the basic ISO 11898 protocol is described which combines the content compression and data gathering techniques and provides high performance services for periodic data exchanges and message transmissions.

The new protocol yields, on the average, a 10-times performance improvement over conventional CAN without worsening neither the responsiveness nor the bus length, and also features a satisfactory degree of compatibility with the original standard protocol.     

RFID读写器发射通道Simulink建模分析

根据ISO18000-6C空中接口协议，提出一种射频识别(RFID)读写器发射通道模型。采用升余弦滤波器抑制带外频谱，减少相邻信道干扰，IQ正交混频架构使得系统可以在双边带调制、单边带调制和载波发送之间切换。在Simulink中构建该发射通道模型，模拟该RFID读写器发射通道的数据链路，获得双边带、单边带调制信号的时域波形及不同滚降因子下电平波纹幅度比。     

An assessment of the current state of product data technologies

Industrial organizations can benefit from the exchange or sharing of digital product data across the borders of disciplines, organizations and vendor-specific solutions. A number of international standards have been developed to make this possible. Of these, ISO 10303 (STEP), ISO/PAS 16739 (IAI/IFC) and ISO 15926 are the most prominent. The first release of STEP was published in 1994, the first release of IAI/IFC in 1997, and ISO 15926 in 2003. Today, many years after their introduction, it must be concluded that the industrial uptake of these standards has been poor. It must be concluded further that, with the current generation of PDT standards, the loss of data or meaning can hardly be avoided. Data exchange between heterogeneous applications is not really supported. In industrial practice, product data are still exchanged in native file formats, less ‘intelligent’ electronic standards, or-even worse-via paper media. The anticipated benefits of PDT standards are not yet reaped by industry. This article discusses the causes of poor performance and poor industrial uptake, with the aim to encourage the development of new strategies and technologies.     

Movement time to edge and non-edge targets

Time to capture a target at the edge of a screen is expected to be less than when the target is slightly away from the screen edge. This is due to the effective target width, in the direction of cursor movement, being large when the target is at the screen edge, allowing a user to control the movement only in a direction perpendicular to the direction of movement. An experiment with 71 participants and a range of Fitts’ Index of Difficulty (ID) showed a strong difference in the capture times of targets at the screen edge and targets placed one pixel from the screen edge. This advantage is typically 100 ms, independent of the ID of the movement.

Practitioner Summary: Movement time to icons placed at the screen edge (no space between icon and screen edge) is faster than when they are placed a short distance from the edge (as in Microsoft Windows).     

A page‐shift transformation format of ISO 10646

ISO 10646 Universal Character Set (UCS) or Unicode covers symbols in most of the World's written languages. There are various UCS transformation formats (UTF). UTF‐8 is compatible with systems that assume 8‐bit characters. One of the problems with UTF‐8 is its space efficiency. For files containing most Asian characters such as Han ideographs, the file sizes increase by about 50% by using UTF‐8. Although the Standard Compression Scheme for Unicode (SCSU) can compress Unicode strings to the size of a locale‐specific character set, it is complicated and is not intended to serve as a general purpose interchange format. This paper proposes a page‐shift transformation format of ISO 10646, called UTF‐S. There are four pages: 1‐byte, 2‐byte, 3‐byte and 4‐byte. Shift to page 0 uses a special code ; shift to page 1, 2, and 3 uses ISO 2022 shift codes SO, SS2, and SS3, respectively. We test several text files and compare these UTF with Big5, a locale‐specific character set. The result shows that the space efficiency of UTF‐S is better than that of UTF‐16 and UTF‐8 and is close to that of SCSU. UTF‐S is suitable for replacing locale‐specific character sets with ISO 10646 in Internet applications, such as the World Wide Web. Copyright © 2001 John Wiley & Sons, Ltd.     

基于模式串的快速标签识别算法

提出一种基于电子标签Tag的ID返回及模式串识别过程的RFID标签识别算法,解决了RFID仲裁过程中存在的零标签响应问题。实验结果表明,对5 000个标签样本进行处理时,该算法所需平均标签响应次数为经典算法Memoryless的48.74%,为Tree Split的33.89%。对标签ID的广播次数平均不超过上述2种算法的76.35%,缩短了标签识别时间,提高了标签识别效率。