基于关键特征相对位置关系的钣金零件检索算法

针对二维钣金类CAD零件相似性的检索,提出一种适用于钣金展开件的相似性检索算法.在分析钣金零件形状特点的基础上,选取设计过程中常用的36种关键特征,建立了关键特征的位置关系模型.该模型以构建关键特征之间的相对位置三角形为基础,具有坐标系无关和旋转无关的特性;以关系模型为依据,提出了钣金件关键特征的相对位置检索算法,并通过实例计算了不同钣金零件之间的相似度.实验结果表明,文中算法是有效的,可满足钣金零件的检索要求,具有实用价值.     

金属板材无模成形加工轨迹生成的研究

介绍了一种采用快速原型制造原理的金属板材无模成形技术．根据快速成形技术中分层制造的思想,从板材无模成形的技术特点出发,采用基于STL文件的金属板材无模成形的加工轨迹生成方法,通过构造STL文件的等距模型并对其进行切片,得到加工轨迹。     

Multiway Decision Graphs for Automated Hardware Verification

Traditional ROBDD-based methods of automated verification suffer from the drawback that they require a binary representation of the circuit. To overcome this limitation we propose a broader class of decision graphs, called Multiway Decision Graphs (MDGs), of which ROBDDs are a special case. With MDGs, a data value is represented by a single variable of abstract type, rather than by 32 or 64 boolean variables, and a data operation is represented by an uninterpreted function symbol. MDGs are thus much more compact than ROBDDs, and this greatly increases the range of circuits that can be verified. We give algorithms for MDG manipulation, and for implicit state enumeration using MDGs. We have implemented an MDG package and provide experimental results.     

钣金件轮廓线早期腐蚀和表面涂层早期剥落问题分析及解决方法

为了解决涂装钣金件轮廓线早期腐蚀和表面涂层早期剥落的问题,对某产品一批钣金外壳的生产全过程进行了跟踪,分析了毛刺去除工艺和涂装工艺对涂装质量的影响。分析结果表明,残留毛刺是轮廓线早期腐蚀的主要原因、氧化膜的存在是导致表面涂层早期剥落的根本原因。     

LS-DYNA在汽车板料成形中的应用

介绍LS-DYNA在汽车板料成型中的应用,其结果的合理性的优化为优化工艺参数和磨具结构提供极为有利的工具.     

系统芯片验证平台设计

使用验证平台可以提高验证效率,传统的验证平台是针对特定的待验证模块设计的,不同的设计需要开发不同的验证平台.验证平台的开发既浪费时间,又很难保证验证平台本身100%正确.文中提出了一种系统芯片验证平台开发方法,按该方法开发出的验证平台具有高可重用性、可扩展性、可升级性、可维护性和自动化等功能,提高了验证平台的开发效率,从而提高了验证效率.     

Verification Approach of Metropolis Design Framework for Embedded Systems

In this paper, we focus on the verification approach of Metropolis, an integrated design framework for heterogeneous embedded systems. The verification approach is based on the formal properties specified in Linear Temporal Logic (LTL) or Logic of Constraints (LOC). Designs may be refined due to synthesis or be abstracted for verification. An automatic abstraction propagation algorithm is used to simplify the design for specific properties. A user-defined starting point may also be used with automatic propagation. Two main verification techniques are implemented in Metropolis the formal verification utilizing the model checker Spin and the simulation trace checking with automatic generated checkers. Translation algorithms from specification models to verification models, as well as algorithms of generated checkers are discussed. We use several case studies to demonstrate our approach for verification of system level designs at multiple levels of abstraction.     

钣金件数控激光切割割嘴路径的优化

提出了分级规划的三步算法来解决优化问题．首先用改进的最近邻算法选择打孔点;然后用智能仿生算法——蚁群算法来求解最佳割嘴路径;最后根据Z轴随动功能约束情况,用路径调整算法来调整前两步算法确定的最佳路径,并获得最终割嘴最佳路径．给出了运行实例并指出进一步的研究工作．     

网络协议的一种构建性验证方法

论文提出了多层自动机映射的思想,并应用此方法构建了复杂协议的构建性验证方法,同时给出了协议构建性验证的逻辑基础和构建步骤。此法有效地避免了复杂协议验证中状态组合爆炸问题。     

模具CAD／CAM系统中弯曲零件的几何描述和数据结构

在模兵CAD/CAM系统中,描述被加工零件的几何特征是最重要的方面之一,它是后续毛坯展开、工艺方案设计、模具参数计算、模具结构设计和模具图绘制的基础。本文重点讨论了典型弯曲件的几何特征,采用“弯曲树”的方法表示弯曲件的基本结构,并用表面模型描述了弯曲件的几何信息和拓扑信息。     

单一尺寸矩形毛坯排样时长板的最优分割

讨论了存在剪刃长度约束时单一尺寸矩形毛坯的优化排样问题,将板材分割成多张子板,通过优化确定子板张数、各子板长度和毛坯在各子板上的排列,使事 板材中所含毛坯数达到最大;并对Agrawal提出的单一尺寸矩形毛了优化排样方法进行扩展,构造出一种分支定界方法,用于解决长板最优分割问题,实验计算结果表明,所述算法非常有效;最后给出了例题数据的排样结果,与企业的通常做法相比较,说明了采用本方法的节材潜力。     

A Formal Verification Environment for Railway Signaling System Design

A fundamental problem in the design and development of embedded control systems is the verification of safety requirements. Formal methods, offering a mathematical way to specify and analyze the behavior of a system, together with the related support tools can successfully be applied in the formal proof that a system is safe. However, the complexity of real systems is such that automated tools often fail to formally validate such systems.This paper outlines an experience on formal specification and verification carried out in a pilot project aiming at the validation of a railway computer based interlocking system. Both the specification and the verification phases were carried out in the JACK (Just Another Concurrency Kit) integrated environment. The formal specification of the system was done by means of process algebra terms. The formal verification of the safety requirements was done first by giving a logical specification of such safety requirements, and then by means of model checking algorithms. Abstraction techniques were defined to make the problem of safety requirements validation tractable by the JACK environment.     

A Design Phase Directed Formal Verification Process

The presence of an effective verification process at an earlier phase of the system development lifecycle will have a greater impact on productivity and product quality than a verification process at a later phase. The usual verification process at the later coding phases involves some form of testing. As high-level design cannot be tested in the same way as code, an option at that phase is some kind of formal verification. A process of verification is presented for the high-level design phase of an operating system development, where both rigorous and formal verification are used, and the rigorous directs the formal. The methodology is based on temporal logic. Formal proofs are manageable on an in-house theorem prover.     

基于Specman的嵌入式软件验证的设计流程

基于Specman的硬件验证环境,给出一个嵌入式软件验证的设计流程。利用该设计流程,对Linux下的USB驱动程序进行验证,并成功找到该程序旧版本中的一个缺陷。     

某型光电设备便携式自动检定系统设计

光电设备的检定一直存在自动化水平低、体积庞大、检测时间长等问题,为了提高检定效率,研制一套便携式光电设备自动检定系统十分必要。以某型光电设备的检定为例,详细介绍了系统的原理及其硬件结构。通过VB和汇编语言混合编程编制了一套软件包,实现检定数据的记录、处理,并具有数据库管理功能。此外,分析了系统误差来源及数据处理方法。实际运行结果显示．该系统有效提高了光电设备检定的效率和精度。     

A New Hybrid Approach to Handwritten Address Verification

The use of optical character recognition (OCR) has achieved considerable success in the sorting of machine-printed mail. The automatic reading of unconstrained handwritten addresses however, is less successful. This is due to the high error rate caused by the wide variability of handwriting styles and writing implements. This paper describes a strategy for automatic handwritten address reading which integrates a postcode recognition system with a hybrid verification stage. The hybrid verification system seeks to reduce the error rate by correlating the postcode against features extracted and words recognised from the remainder of the handwritten address. Novel use of syntactic features extracted from words has resulted in a significant reduction in the error rate while keeping the recognition rate high. Experimental results on a testset of 1,071 typical Singapore addresses showed a significant improvements from 24.0% error rate, 71.2% correct recognition rate, and 4.8% rejection rate using raw OCR postcode recognition to 0.4% error rate, 65.1% correct recognition rate, and 34.5% rejection rate using the hybrid verification approach. The performance of the approach compares favourably with the currently installed commercial system at Singapore Post, which achieved 0.7% error rate, 47.8% correct recognition rate, and 51.5% rejection rate for 6-digit postcode using the same test data.     

DMA控制器的一种硬件验证方法

在微处理器或SOC芯片设计过程中,DMA控制器的硬件仿真验证是难以解决的问题之一,因为DMA控制器与包括微处理器核和内存控制器在内的几乎所有部件都有数据通信,如将所有部件集成后进行仿真测试,则一旦发现错误后,定位错误会非常困难.本文为此提出了一种简化测试模型和验证方法,可以有效解决上述问题.     

专用经纬仪快速检定系统设计

为了提高经纬仪检定的效率和精度,设计了一种专用的经纬仪快速检定系统。文章介绍了其组成、工作原理和软件设计,着重介绍了独特的光学读数图像自动识别装置及各仪器与计算机的通讯,并对系统的测量不确定度进行了评定。实践证明,系统完全符合经纬仪检定的要求,大大降低了检定人员的劳动强度,为检定工作自动化程度的提高提供了一个有用的借鉴。     

输入数据校验设计与软件可靠性

由于数据检查机制的缺乏 ,软件可靠性难以得到保证。分析了人类常犯的几种数据输入错误后 ,从测试的角度 ,给出了两个软件开发的体会、经验和应对数据输入出错方案。     

电子天平辅助检定系统设计

介绍了一种适用于电子天平的辅助检定系统设计方法,系统具备辅助检定、数据计算、文档生成、台账管理等功能,在系统辅助下,只需根据提示放置相应砝码即可完成检定工作,大幅提高了检定工作的作业效率,设计方法通用性强,具有良好的推广应用前景。