A novel method for automatic ultra-precision alignment is presented.This method relies on the modified Moiré technique,and alignment marks are used in the form of gratings.The modified Moiré technique can ef...A novel method for automatic ultra-precision alignment is presented.This method relies on the modified Moiré technique,and alignment marks are used in the form of gratings.The modified Moiré technique can effectively improve detecting sensitivity of signals and simplify the control system by using only one pair of laser-Moiré sensors.We present the mathematical model and simulation results of diffracting two gratings.The effect of various parameters on Moiré signals is studied theoretically and experimentally,and the results are found to be consistent.A computer controlled alignment device using one pair of Moiré sensors is designed.The device can achieve a fully automatic precision alignment by the modified Moiré signal.The experimental result shows that the alignment device can obtain the resolution of 5 nm and the positioning accuracy of ±0 5 μm.展开更多
Antiviral software systems (AVSs) have problems in identifying polymorphic variants of viruses without explicit signatures for such variants. Alignment-based techniques from bioinformatics may provide a novel way to g...Antiviral software systems (AVSs) have problems in identifying polymorphic variants of viruses without explicit signatures for such variants. Alignment-based techniques from bioinformatics may provide a novel way to generate signatures from consensuses found in polymorphic variant code. We demonstrate how multiple sequence alignment supplemented with gap penalties leads to viral code signatures that generalize successfully to previously known polymorphic variants of JS. Cassandra virus and previously unknown polymorphic variants of W32.CTX/W32.Cholera and W32.Kitti viruses. The implications are that future smart AVSs may be able to generate effective signatures automatically from actual viral code by varying gap penalties to cover for both known and unknown polymorphic variants.展开更多
Antiviral software systems (AVSs) have problems in detecting polymorphic variants of viruses without specific signatures for such variants. Previous alignment-based approaches for automatic signature extraction have s...Antiviral software systems (AVSs) have problems in detecting polymorphic variants of viruses without specific signatures for such variants. Previous alignment-based approaches for automatic signature extraction have shown how signatures can be generated from consensuses found in polymorphic variant code. Such sequence alignment approaches required variable length viral code to be extended through gap insertions into much longer equal length code for signature extraction through data mining of consensuses. Non-nested generalized exemplars (NNge) are used in this paper in an attempt to further improve the automatic detection of polymorphic variants. The important contribution of this paper is to compare a variable length data mining technique using viral source code to the previously used equal length data mining technique obtained through sequence alignment. This comparison was achieved by conducting three different experiments (i.e. Experiments I-III). Although Experiments I and II generated unique and effective syntactic signatures, Experiment III generated the most effective signatures with an average detection rate of over 93%. The implications are that future, syntactic-based smart AVSs may be able to generate effective signatures automatically from malware code by adopting data mining and alignment techniques to cover for both known and unknown polymorphic variants and without the need for semantic (run-time) analysis.展开更多
针对现有任意反射面速度干涉仪(velocity interferometer system for any reflector,VISAR)装置中依靠人工准直光路的现状,同时为满足未来对远程自动化控制的需求,提出一种新的光路自动准直的方法。该方法通过互补金属氧化物半导体(comp...针对现有任意反射面速度干涉仪(velocity interferometer system for any reflector,VISAR)装置中依靠人工准直光路的现状,同时为满足未来对远程自动化控制的需求,提出一种新的光路自动准直的方法。该方法通过互补金属氧化物半导体(complementary metal oxide semiconductor,CMOS)间接测量并以光斑的像素偏差为系统输入,通过系数矩阵转换和离散模糊反馈控制方法快速消除误差。基于Windows的控制和自动化技术(the Windows control and automation technology,TwinCAT)中视觉和运动等模块,将各模块分别运行在不同的实时内核中,消除了视觉与运动控制模块间的通信环节,实现了快速实时的闭环控制。经过冲击波速度测量实验验证,该系统实现了远程“一键式”自动准直,可将准直时间缩短到2 s,准直精度为4.5μm,解决了现有装置人工调节效率不高的问题,提高了系统的精度和稳定性。展开更多
为解决数控机床刀具无拆卸条件下,基于机械臂的刀具损伤视觉检测系统对准对焦调节耗时长、计算分析方法鲁棒性差等难题,提出了一种融合YOLOv5网络智能感兴趣区域(region of interest, ROI)的机器人视觉系统自动对准对焦方法。首先,利用...为解决数控机床刀具无拆卸条件下,基于机械臂的刀具损伤视觉检测系统对准对焦调节耗时长、计算分析方法鲁棒性差等难题,提出了一种融合YOLOv5网络智能感兴趣区域(region of interest, ROI)的机器人视觉系统自动对准对焦方法。首先,利用ROI模型检测并定位刀具中心,通过九点标定法计算机械臂末端对准坐标;然后自适应筛选ROI对焦窗口,采用改进的Laplacian函数计算清晰度评价值以确定最佳刀具图像。在实际设备上开展实验后结果表明,所提方法比一般方法灵敏度至少提高1.63倍,平均中心点误差为3.76像素,有效提升了刀具损伤视觉检测系统的准确度和灵活性。展开更多
文摘A novel method for automatic ultra-precision alignment is presented.This method relies on the modified Moiré technique,and alignment marks are used in the form of gratings.The modified Moiré technique can effectively improve detecting sensitivity of signals and simplify the control system by using only one pair of laser-Moiré sensors.We present the mathematical model and simulation results of diffracting two gratings.The effect of various parameters on Moiré signals is studied theoretically and experimentally,and the results are found to be consistent.A computer controlled alignment device using one pair of Moiré sensors is designed.The device can achieve a fully automatic precision alignment by the modified Moiré signal.The experimental result shows that the alignment device can obtain the resolution of 5 nm and the positioning accuracy of ±0 5 μm.
文摘Antiviral software systems (AVSs) have problems in identifying polymorphic variants of viruses without explicit signatures for such variants. Alignment-based techniques from bioinformatics may provide a novel way to generate signatures from consensuses found in polymorphic variant code. We demonstrate how multiple sequence alignment supplemented with gap penalties leads to viral code signatures that generalize successfully to previously known polymorphic variants of JS. Cassandra virus and previously unknown polymorphic variants of W32.CTX/W32.Cholera and W32.Kitti viruses. The implications are that future smart AVSs may be able to generate effective signatures automatically from actual viral code by varying gap penalties to cover for both known and unknown polymorphic variants.
文摘Antiviral software systems (AVSs) have problems in detecting polymorphic variants of viruses without specific signatures for such variants. Previous alignment-based approaches for automatic signature extraction have shown how signatures can be generated from consensuses found in polymorphic variant code. Such sequence alignment approaches required variable length viral code to be extended through gap insertions into much longer equal length code for signature extraction through data mining of consensuses. Non-nested generalized exemplars (NNge) are used in this paper in an attempt to further improve the automatic detection of polymorphic variants. The important contribution of this paper is to compare a variable length data mining technique using viral source code to the previously used equal length data mining technique obtained through sequence alignment. This comparison was achieved by conducting three different experiments (i.e. Experiments I-III). Although Experiments I and II generated unique and effective syntactic signatures, Experiment III generated the most effective signatures with an average detection rate of over 93%. The implications are that future, syntactic-based smart AVSs may be able to generate effective signatures automatically from malware code by adopting data mining and alignment techniques to cover for both known and unknown polymorphic variants and without the need for semantic (run-time) analysis.
文摘针对现有任意反射面速度干涉仪(velocity interferometer system for any reflector,VISAR)装置中依靠人工准直光路的现状,同时为满足未来对远程自动化控制的需求,提出一种新的光路自动准直的方法。该方法通过互补金属氧化物半导体(complementary metal oxide semiconductor,CMOS)间接测量并以光斑的像素偏差为系统输入,通过系数矩阵转换和离散模糊反馈控制方法快速消除误差。基于Windows的控制和自动化技术(the Windows control and automation technology,TwinCAT)中视觉和运动等模块,将各模块分别运行在不同的实时内核中,消除了视觉与运动控制模块间的通信环节,实现了快速实时的闭环控制。经过冲击波速度测量实验验证,该系统实现了远程“一键式”自动准直,可将准直时间缩短到2 s,准直精度为4.5μm,解决了现有装置人工调节效率不高的问题,提高了系统的精度和稳定性。
文摘为解决数控机床刀具无拆卸条件下,基于机械臂的刀具损伤视觉检测系统对准对焦调节耗时长、计算分析方法鲁棒性差等难题,提出了一种融合YOLOv5网络智能感兴趣区域(region of interest, ROI)的机器人视觉系统自动对准对焦方法。首先,利用ROI模型检测并定位刀具中心,通过九点标定法计算机械臂末端对准坐标;然后自适应筛选ROI对焦窗口,采用改进的Laplacian函数计算清晰度评价值以确定最佳刀具图像。在实际设备上开展实验后结果表明,所提方法比一般方法灵敏度至少提高1.63倍,平均中心点误差为3.76像素,有效提升了刀具损伤视觉检测系统的准确度和灵活性。
