Accelerated generation of holograms with ultra-low memory symmetrically high-compressed look-up table

Computer-generated holography technology has been widely applied,and as research in this field deepens,the demand for memory and computational power in small AR and VR devices continues to increase.This paper presents a hologram generation method,i.e.,a symmetrically high-compressed look-up table method,which can reduce memory usage by50%.In offline computing,half of the basic horizontal and vertical modulation factors are stored,halving the memory requirements without affecting inline speed.Currently,its potential extends to various holographic applications,including the production of optical diffraction elements.

A general purpose exact Rayleigh scattering look-up table for ocean color remote sensing

The current exact Rayleigh scattering calculation of ocean color remote sensing uses the look-up table （LUT）, which is usually created for a special remote sensor and cannot be applied to other sensors. For practical application, a general purpose Rayleigh scattering LUT which can be applied to all ocean color remote sensors is generated. An adding-doubling method to solve the vector radiative transfer equation in the plane-parallel atmosphere is deduced in detail. Compared with the exact Rayleigh scattering radiance derived from the MODIS exact Rayleigh scattering LUT, it is proved that the relative error of Rayleigh scattering calculation with the adding-doubling method is less than 0.25%, which meets the required accuracy of the atmospheric correction of ocean color remote sensing. Therefore, the adding-doubling method can be used to generate the exact Rayleigh scattering LUT for the ocean color remote sensors. Finally, the general purpose exact Rayleigh scattering LUT is generated using the adding-doubling method. On the basis of the general purpose LUT, the calculated Rayleigh scattering radiance is tested by comparing with the LUTs ofMODIS, SeaWiFS and the other ocean color sensors, showing that the relative errors are all less than 0.5%, and this general purpose LUT can be applied to all ocean color remote sensors.

Fine Doppler shift acquisition algorithm for BeiDou software receiver by a look-up table

The BeiDou software receiver uses the fast Fourier transform(FFT)to perform the acquisition.The Doppler shift estimation accuracy should be less than 500 Hz to ensure satellite signals to enter a locked state in the tracking loop.Since the frequency step is usually 500 Hz or larger,the Doppler shift estimation accuracy cannot guarantee that satellite signals are brought into a stable tracking state.The straightforward solutions consist in increasing the sampling time and using zero-padding to improve the frequency resolution of the FFT.However,these solutions intensify the complexity and amount of computation.The contradiction between the acquisition accuracy and the computational load leads us to research for a more simple and effective algorithm,which achieves fine acquisition by a look-up table.After coarse acquisition using the parallel frequency acquisition(PFA)algorithm,the proposed algorithm optimizes the Doppler shift estimation through the look-up table method based on the FFT results to improve the acquisition accuracy of the Doppler shift with a minimal additional computing load.When the Doppler shift is within the queryable range of the table,the proposed algorithm can improve the Doppler shift estimation accuracy to 50 Hz for the BeiDou B1I signal.

Performance of global look-up table strategy in digital image correlation with cubic B-spline interpolation and bicubic interpolation

Global look-up table strategy proposed recently has been proven to be an efficient method to accelerate the interpolation, which is the most time-consuming part in the iterative sub-pixel digital image correlation （DIC） algorithms. In this paper, a global look-up table strategy with cubic B-spline interpolation is developed for the DIC method based on the inverse compositional Gauss-Newton （IC-GN） algorithm. The performance of this strategy, including accuracy, precision, and computation efficiency, is evaluated through a theoretical and experimental study, using the one with widely employed bicubic interpolation as a benchmark. The global look-up table strategy with cubic B-spline interpolation improves significantly the accuracy of the IC-GN algorithm-based DIC method compared with the one using the bicubic interpolation, at a trivial price of computation efficiency.

Research of NO_(2) vertical profiles with look-up table method based on MAX-DOAS

Obtaining the vertical distribution profile of trace gas is of great significance for studying the diffusion procedure of air pollution.In this article,a look-up table method based on multi-axis differential optical absorption spectroscopy(MAX-DOAS)technology is established for retrieving the tropospheric NO_(2) vertical distribution profiles.This method retrieves the aerosol extinction profiles with minimum cost function.Then,the aerosol extinction profiles and the atmospheric radiation transfer model(RTM)are employed to establish the look-up table for retrieving the NO_(2) vertical column densities(VCDs)and profiles.The measured NO_(2) differential slant column densities(DSCDs)are compared with the NO_(2) DSCDs simulated by the atmospheric RTM,and the NO_(2) VCDs,the weight factor of NO_(2) in the boundary layer,and the boundary layer height are obtained by the minimization process.The look-up table is established to retrieve NO_(2) VCDs based on MAX-DOAS measurements in Huaibei area,and the results are compared with the data from Copernicus Atmospheric Monitoring Service(CAMS)model.It is found that there are nearly consistent and the correlation coefficient R2 is more than 0.86.The results show that this technology provides a more convenient and accurate retrieval method for the stereoscopic monitoring of atmospheric environment.

On-line Popularity Monitoring Method Based on Bloom Filters and Hash tables for Differentiated Traffic

Towards line speed and accurateness on-line content popularity monitoring on Content Centric Networking(CCN) routers, we propose a three-stage scheme based on Bloom filters and hash tables for differentiated traffic. At the first stage, we decide whether to deliver the content to the next stage depending on traffic types. The second stage consisting of Standard Bloom filters(SBF) and Counting Bloom filters(CBF) identifies the popular content. Meanwhile, a scalable sliding time window based monitoring scheme for different traffic types is proposed to implement frequent and real-time updates by the change of popularities. Hash tables according with sliding window are used to record the popularity at the third stage. Simulation results reveal that this method reaches a 40 Gbps processing speed at lower error probability with less memory, and it is more sensitive to the change of popularity. Additionally, the architecture which can be implemented in CCN router is flexible and scalable.

60t高速五线旋转式冷拔机组浅析

本文实现了一种具有竖直提升上料、多模式毛管横移布料、芯棒水平穿芯、双工位旋转式芯棒台为特征的高速无缝钢管冷拔机组。该机组实现了冷拔管生产过程散料、提升上料、下位拔制、下料等工序自动运行;可实现最多五支直径φ28~φ63.5mm、壁厚3.5~10mm、长度8~26m碳钢及低合金钢管同时拔制;机组公称拔制力最大60t,拔制速度最高50m/min。该设备提升了国内冷拔管材生产机组设计、制造水平以及企业生产技术水平,对促进我国钢管行业技术装备发展具有深远意义。

Area and Speed Efficient Implementation of Symmetric FIR Digital Filter through Reduced Parallel LUT Decomposed DA Approach

This brief proposes an area and speed efficient implementation of symmetric finite impulse response (FIR) digital filter using reduced parallel look-up table (LUT) distributed arithmetic (DA) based approach. The complexity lying in the realization of FIR filter is dominated by the multiplier structure. This complexity grows further with filter order, which results in increased area, power, and reduced speed of operation. The speed of operation is improved over multiply-accumulate approach using multiplier less conventional DA based design and decomposed DA based design. Both the structure requires B clock cycles to get the filter output for the input width of B, which limits the speed of DA structure. This limitation is addressed using parallel LUTs, called high speed DA FIR, at the expense of additional hardware cost. With large number of taps, the number of LUTs and its size also becomes large. In the proposed method, by exploiting coefficient symmetry property, the number of LUTs in the decomposed DA form is reduced by a factor of about 2. This proposed approach is applied in high speed DA based FIR design, to obtain area and speed efficient structure. The proposed design offers around 40% less area and 53.98% less slice-delay product (SDP) than the high throughput DA based structure when it’s implemented over Xilinx Virtex-5 FPGA device-XC5VSX95T-1FF1136 for 16-tap symmetric FIR filter. The proposed design on the same FPGA device, supports up to 607 MHz input sampling frequency, and offers 60.5% more speed and 67.71% less SDP than the systolic DA based design.

A High Speed Autofocusing System for Micro System Applications

In this paper,we present a high speed autofocus system for micro system applications and design a look-up-table based autofocusing algorithm for applications when a target object is always visible,e.g.,manufacturing parts with alignment fiducials.We perform an evaluation of 24 focus measures to verify that which focus measure is the best for the look-up-table based method.From the evaluation,we find that the Chebyshev moments-based focus measure（CHEB） is the most suitable.Furthermore,we also develop a look-up-table based autofocus system that uses CHEB as the focus measure.In training phase,we offline construct a table from training images of an object that are captured at several lens distances.Each entry of table consists of focus measure computed from image and lens distance.In working phase,given an input image,the algorithm first computes the focus measure and then finds the best match focus measure from the table and looks up the corresponding lens position for moving it into the in-focus position.Our algorithm can perform autofocusing within only 2 steps of lens moving.The experiment shows that the system can perform high speed autofocusing of micro objects.

面向对象的数控机床XY工作台动态定位误差分析与建模

为研究切削力和速度共同影响下对数控机床XY工作台动态定位误差的影响规律,全面分析了XY工作台在切削力影响下的动态误差特性。建立了由滚珠丝杆组件、导轨系统、工作台台面和摩擦力等误差源所引起的动态定位误差分量精确计算模型,推导了XY工作台动态定位误差理论模型。根据其理论模型可知,切削力、运动速度和摩擦力是导致XY工作台动态定位误差的主要来源。通过对切削力下动态定位误差理论模型计算和仿真分析,验证了该理论模型的有效性,证明了切削力对工作台的动态定位误差存在影响,且在不同切削力下工作台运动速度为4mm/s时动态定位误差最小,将该速度定义为最佳运动速度。其研究结果为建立数控机床的定位误差预测与补偿模型,提高加工精度奠定了良好基础。

基于高速视觉的乒乓球旋转速度实时测量方法

针对目前大多数乒乓球机器人视觉系统只能提供乒乓球的位置信息而未考虑旋转,难以对旋转球进行精准预测的问题,提出一种基于高速视觉的乒乓球旋转速度实时测量方法。为解决高速旋转乒乓球转速测量问题,提出一种全新视觉系统方案,满足高速旋转球的转速测量要求;针对商标识别过程中未考虑商标的完整性问题,提出一种基于轮廓拼接的商标中心三维位置求解方法,减小商标中心的计算误差,提高旋转测量精度;根据商标中心在空间中的运动对乒乓球旋转进行估计。最后利用自制的旋转验证平台对该方法进行验证,实验结果表明所提出的方法能够实现高速旋转球的精确转速估计,在乒乓球低速旋转下也具有高精度的旋转测量结果。

The establishment of crystal position look-up table for positron emission tomography with block detectors

A method has been developed to establish the crystal position look-up table for positron emission tomography with block detectors. It is based on the principle that the counts in crystal position histogram obey the Gaussian mixture model (GMM). This method has taken full consideration of the characteristics of the GMM and the detector itself. The experimental results have proved that it is simple, reliable, and universal.

CRC Look-up Table Optimization for Single-Bit Error Correction

Many communication systems use the cyclic redundancy code （CRC） technique for protecting key data fields from transmission errors by enabling both single-bit error correction and multi-bit error detection. The look-up table design is very important for the error-correction implementation. This paper presents a CRC look-up table optimization method for single-bit error correction. The optimization method minimizes the address length of the pre-designed look-up table while satisfying certain restrictions. The circuit implementation is also presented to show the feasibility of the method in the application specific integrated circuit design. An application of the optimization method in the generic framing procedure protocol is implemented using field programmable gatearrays. The result shows that the memory address length has been minimized, while keeping a very simple circuit implementation.

Study of the influences of rotary table speed on stick-slip vibration of the drilling system

Stick-slip vibration presents one of the major causes of drilling problems,such as premature tool failures,low drilling efficiency and poor wellbore quality.The objective of this work is to investigate the influences of rotary table speed(RTS)on stick-slip phenomenon of the drilling system.In this study,the drilling system is treated as a lumped torsional pendulum model of which the bit/rock interaction is regarded as Coulomb friction.By analyzing cases with different RTS,two types of vibrations on the bit are found:stick-slip vibration and uniform motion.With an increase in the RTS,the stick-slip vibration on the drill bit disappears once the RTS arrives at its critical value.For the cases that stick-slip vibrations occur,the phase trajectories converge toward a limit cycle.For the cases that stick-slip vibration does not appear,the drill bit tends to stabilize at a uniform motion and the phase trajectories correspond to contracting spirals observed in the phase plane.

ARJ21非标准条件下最大起飞重量修正方法研究

制定ARJ21机型非标准条件下重量修正逻辑,并结合空客机型最大起飞重量确定流程,从防冰修正、道面修正和QNH修正3种情况进行非标准条件下的最大起飞重量变化规律研究,并进行修正值的计算及合理性验证,得到完整的非标准条件下最大起飞重量的确定流程,为其他支线及干线国产民机起飞分析表修正项制定提供指导性参考,提高其适应性和竞争力。

高速铁路灾害监测系统故障诊断方法研究

作为高速铁路安全保障系统之一,高速铁路灾害监测系统(简称:灾害监测系统)的稳定运行是列车在灾害天气和突发异物侵限事件下安全运行的根本保障。针对灾害监测系统故障数据特点,构建了基于失效模式与影响分析(FMEA,Failure Mode and Effects Analysis)的灾害监测系统故障分析表,对该系统的故障表现、故障原因和影响进行分析。在此基础上,提出了基于随机森林算法的灾害监测系统故障诊断方法。通过对比分析可知,该方法优于传统的基于C4.5决策树的故障诊断方法,有助于灾害监测系统故障的快速诊断、定位和处置,减少人工排查设备故障的工作量,为灾害监测系统的运营维护提供技术支持。

Device and circuit analysis of a sub 20 nm double gate MOSFET with gate stack using a look-up-table-based approach

In this paper, we explore the possibility of mapping devices designed in TCAD environment to its modeled version developed in cadence virtuoso environment using a look-up table （LUT） approach. Circuit simu- lation of newly designed devices in TCAD environment is a very slow and tedious process involving complex scripting. Hence, the LUT based modeling approach has been proposed as a faster and easier alternative in ca- dence environment. The LUTs are prepared by extracting data from the device characteristics obtained from device simulation in TCAD. A comparative study is shown between the TCAD simulation and the LUT-based alternative to showcase the accuracy of modeled devices. Finally the look-up table approach is used to evaluate the perform- ance of circuits implemented using 14 nm nMOSFET.

Accurate and fast table look-up models for leakage current analysis in 65nm CMOS technology

Novel physical models for leakage current analysis in 65 nm technology are proposed. Taking into consideration the process variations and emerging effects in nano-scaled technology, the presented models are capable of accurately estimating the subthreshold leakage current and junction tunneling leakage current in 65 nm technology. Based on the physical models, new table look-up models are developed and first applied to leakage current analysis in pursuit of higher simulation speed. Simulation results show that the novel physical models are in excellent agreement with the data measured from the foundry in the 65 nm process, and the proposed table look-up models can provide great computational efficiency by using suitable interpolation techniques. Compared with the traditional physical-based models, the table look-up models can achieve 2.5X speedup on average on a variety of industry circuits.

多方向移动训练对青少年乒乓球运动员移动速度与灵敏性的影响研究

目的:探讨多方向移动训练对青少年乒乓球运动员移动速度与灵敏性的影响,旨在为提高我国乒乓球运动员的运动能力提供参考。方法:16名辽宁省青少年乒乓球运动员随机分为实验组和对照组,每组各8人。在为期8周的实验干预期间,实验组进行多方向移动训练,对照组进行传统体能训练,训练前后分别测试两组运动员的移动速度(30m冲刺跑、T字型跑、1min跳绳)、灵敏性(伊利诺斯跑、十字象限跳、左右横跨)以及专项指标(球台推挡侧身扑右、全台不定点摆速度),比较实验前后两组运动员各指标的变化。结果:实验前对照组和实验组移动速度与灵敏性各指标成绩均无显著性差异(P>0.05);实验后对照组移动速度与灵敏性各指标成绩与实验前相比均无显著性差异(P>0.05),实验组移动速度和灵敏性各指标成绩与实验前相比,除30m冲刺跑略有提高但差异不显著(P>0.05),其他指标成绩均有显著性提高(P<0.05);实验后实验组移动速度与灵敏性各指标成绩除30m冲刺跑之外其他指标成绩均显著高于对照组(P<0.05)。结论:多方向移动训练能够有效提高青少年乒乓球运动员的移动速度与灵敏性,且训练效果要好于传统体能训练方式。

基于话题标签的微博舆情热点挖掘系统设计

为在微博舆情信息高速转发时段内实现对热点数据的精准挖掘,文中设计一种基于话题标签的微博舆情热点挖掘系统。首先确定框架体系连接形式,并根据热点信息定义结果建立话题标签模型。以此为基础,对热点信息散列表进行排重处理,完成对微博舆情热点数据的处理。最后,联合采集到的目标信息样本对论坛结构进行分割处理,完成挖掘系统设计。实验结果表明,在话题标签模型作用下,系统主机对于热点数据的挖掘准确率较高,可以在微博舆情信息高速转发时段内实现对热点数据的精准挖掘,满足实际应用需求;与基于机器阅读理解的挖掘系统、基于跨语言神经主题模型的挖掘系统相比,这种新型挖掘系统能够在微博舆情信息高速转发时段内,对热点数据进行精准挖掘,与设计初衷相符合。