STEP-NC译码器及其关键技术

为实现与产品模型数据交换标准兼容的数控数据接口在数控系统中的应用,开发了STEP-NC译码器.阐述了译码器的工作原理,将译码器按照逻辑关系分为六个功能模块,介绍了各个模块的功能和实现方法.详细论述了STEP-NC译码器实现中的三项关键技术:类库设计、刀轨规划参数读取方法和STEP-NC坐标系转换.最后,结合一个STEP-NC程序实例,利用所开发的STEP-NC译码器,规划出该程序实例的完整刀具轨迹,通过STEP-NC铣削仿真系统对刀具轨迹及零件模型进行切削仿真.仿真结果表明,所开发的STEP-NC译码器是正确可行的.     

弱对偶基下RS码译码方法的研究

讨论了高速RS码译码器的设计问题.研究了有限域元素在弱对偶基(WDB)下的表示,基于弱对偶基下的最优弱对偶基的计算方法,给出了有限域比特并行乘法器的设计;采用了一种可以避免求逆运算的修正BM迭代算法,并且利用这样的迭代算法和基于弱对偶基的比特并行乘法器构成了广泛应用的RS码的译码器.对译码器定量分析的结果表明:弱对偶基下比特并行乘法器设计复杂度降低,便于VLSI实现;修正BM迭代算法使得简单的硬件实现成为可能,且有利于On-The-Fly纠错.译码器的数据吞吐率可达较高值,有利于高速应用场合.     

FPGA中宽边译码器的测试方法研究

现有的关于FPGA的测试主要集中在可编程逻辑和互连线资源,而没有涉及FPGA中的宽边译码器的测试。本文提出了一种测试FPGA中宽边译码器的方法,该方法实现了FPGA中的宽边译码器的逻辑资源及其相连的长线资源的全覆盖测试。该实验采用Xilinx公司的XC4000E系列芯片,在基于SOC软硬件协同技术的FPGA自动测试系统中进行测试。实验结果表明,用本文提出的4次配置图形和测试向量能够完成全覆盖测试。     

基于FPGA的卫星导航信号viterbi译码方法研究

在介绍Xilinx公司FPGA的Viterbi译码器IP核译码模块设计的基础上,分析了广泛应用于卫星导航信号中的卷积编码及viterbi译码过程,重点分析了关键问题,提出了具体模块设计方案,并进行仿真和硬件验证。     

北京科仪厂两种新产品面市

<正> 北京科学仪器厂研制的TTY-1型通用台式译码器和BK—1型条码扫描光笔,于最近通过技术鉴定。 TTY-1型通用台式译码器主要适用于光笔条形码扫描器;BK-190型条码扫描光笔是一     

正交译码接口电路的原理与设计

介绍了正交译码接口电路的工作原理，分析了数字延迟噪声滤波器、四倍频正交译码器、抑制逻辑等单元逻辑状态，提出了正交译码接口电路在数字闭环运动控制系统和数字数据输入系统的设计方案。     

正确曝光与光敏电阻

本文以摄影技术为例,分析光敏电阻在实际应用中的一些具体技术问题,这些问题对于其它的光电自动控制器,指示器,检测器、显示器、译码器和发生器等也是有益的     

激光全角度扫描条码识读器研究

本文详细讨论了激光全角度扫描条码识读器的关键技术，对光学扫描图案的布局、扫描激光束的空间分布特性、扫描图案的产生、接收系统的渐晕特性和自动增益控制、高速ＤＳＰ芯片实现高速译码器的原理和方法等进行了详细的分析     

基于单片机的多路数据采集系统设计

本系统采用ADuC841单片机作为核心处理器,对32路模拟信号进行数据采集、分析和处理,通过数码管显示所有通道中最大、最小数据的数值和通道号。系统采用单片机、数据选择器、译码器及相关硬件电路进行设计,能对32路模拟数据进行采集,然后根据实际需要由单片机对数据进行实时分析和处理。     

条形码物流管理技术在制造自动化系统(MAS)中的应用

对条形码识别技术的基本概念、在制造自动化系统(MAS)中的应用与实施、编码方案以及条形码物流管理系统的工作原理及运作过程作了详细的论述，并介绍了该系统专用译码器的特点。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.