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 novel control strategy for reproducing the floor motions of high-rise buildings by earthquake-simulating shake tables

To enable the experimental assessment of the seismic performance of full-scale nonstructural elements with multiple engineering parameters(EDPs),a three-layer testbed named Nonstructural Element Simulator on Shake Table(NEST)has been developed.The testbed consists of three consecutive floors of steel structure.The bottom two floors provide a space to accommodate a full-scale room.To fully explore the flexibility of NEST,we propose a novel control strategy to generate the required shake table input time histories for the testbed to track the target floor motions of the buildings of interest with high accuracy.The control strategy contains two parts:an inverse dynamic compensation via simulation of feedback control systems(IDCS)algorithm and an offline iteration procedure based on a refined nonlinear numerical model of the testbed.The key aspects of the control strategy were introduced in this paper.Experimental tests were conducted to simulate the seismic responses of a full-scale office room on the 21^(st)floor of a 42-story high-rise building.The test results show that the proposed control strategy can reproduce the target floor motions of the building of interest with less than 20%errors within the specified frequency range.

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.

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.

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.

Study on An Absolute Non-Collision Hash and Jumping Table IP Classification Algorithms

In order to classify packet, we propose a novel IP classification based the non-collision hash and jumping table trie-tree (NHJTTT) algorithm, which is based on noncollision hash Trie-tree and Lakshman and Stiliadis proposing a 2-dimensional classification algorithm (LS algorithm). The core of algorithm consists of two parts: structure the non-collision hash function, which is constructed mainly based on destination/source port and protocol type field so that the hash function can avoid space explosion problem; introduce jumping table Trie-tree based LS algorithm in order to reduce time complexity. The test results show that the classification rate of NHJTTT algorithm is up to 1 million packets per second and the maximum memory consumed is 9 MB for 10 000 rules. Key words IP classification - lookup algorithm - trie-tree - non-collision hash - jumping table CLC number TN 393.06 Foundation item: Supported by the Chongqing of Posts and Telecommunications Younger Teacher Fundation (A2003-03).Biography: SHANG Feng-jun (1972-), male, Ph.D. candidate, lecture, research direction: the smart instrument and network.

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.

Visualizing Data Tree-Table Based on the Database

The data tree table is a type of data structure consisting of data tree and table, which has a wide field of applications. The visual and dynamic growing algorithm of data tree table and its software method are presented based on the theory of the data structure and visual technology of software. The method of the expression and management of data tree table with relational mode are explored.

VCA Direct-Drive High Speed and Precision XY Table

In order to compensate for the limitation of conventional XY table used in semiconductor integrated circuits(IC) packaging and improve its speed and accuracy, a voice coil actuator (VCA) direct-drive high-speed and precision positioning XY table used in wire bonder was proposed. Also, a novel flexible decoupling mechanism was used in the positioning table, and the small moving mass enabled the positioning table to move at high speed and precision. XY table deformation interference caused by assembly error and instant interference generated by dynamic load moving with high speed and acceleration can be eliminated through the flexible decoupling mechanism. Considering the positioning table as lumped mass spring system,the dynamic equations of the mechanical system and the VCA were built according to the Newton mechanics principle and electromagnetic theory. Then the electromechanical coupling control model of the system was created through Laplace transform. Based on displacement PID controller, the loop-locked controlling algorithm of the positioning system was investigated. The dynamic control algorithm effectively improved the system dynamic performance. The precision test of the prototype machine was carried out, and the results validated the correctness of the model and the theory. Compared with traditional XY table, the table has higher speed, acceleration and positioning accuracy.

基于路径相似表与个体迁移策略的多路径覆盖测试

将遗传算法用于多路径覆盖测试中是个研究热点,在新旧种群迭代过程中,旧种群中可能包含其他子种群的优秀个体,这部分个体未被充分利用,造成资源浪费;同时,种群中的个体数会远大于可达路径数,而每个个体都会经过某一条可达路径,这样会有多个个体经过同一条路径,导致重复计算个体与目标路径的相似度。基于此,提出结合路径相似表与个体迁移的多路径覆盖测试方法以提高测试效率。通过路径相似表存储已计算得到的路径相似度值,避免该值被重复计算,减少测试时间。在进化过程中,将个体路径与其他目标路径进行比较,若相似度达到阈值,则将此优秀个体迁移至该路径对应的子种群中,提高个体利用率并减少进化代数。由实验可知,该方法与其他六种同类经典方法在八个程序上的平均生成时间降低最高达44.64%,最低为2.64%,平均进化代数降低最高达35.08%,最低为6.13%,故该方法有效地提高了测试效率。

DWT算法在乒乓球动作识别分析中的应用

针对传统乒乓球动作识别未考虑动作的时序性和动态特性的问题,研究在二维DWT算法的基础上引入奇异值分解,设计出一种改进DWT算法,以获得乒乓球动作的局部特征,从而提升其识别准确率。实验结果显示:在识别准确率计算中,改进DWT算法的平均识别准确率为97.8%,优于其他算法,表明其识别精度较高;在识别时间计算中,改进DWT算法的识别时间与其他算法相比,均下降了50%左右,表明其识别效率较高。以上结果证明了改进DWT算法的优越性能,为乒乓球的动作识别提供了有效的技术支持。

基于邻接比特压缩表的频繁闭项集挖掘算法

频繁闭项集(Frequent Closed Items,FCI)是一种表示事物之间关联关系的有效方式,它能克服频繁项集(Frequent Items,FI)信息冗余的缺点。FCI挖掘算法研究旨在以更优的时空效率,在原始数据集中找到所有的FCI。相关研究成果重在关注时间效率的提升,但空间效率欠佳。提出一种高空间压缩率数据结构——邻接比特压缩表(Compressed Adjacency Byte table,Cab-table),将项集与交易集压缩到剔除全部0之后的比特表中,使空间高度压缩。基于此数据结构的频繁闭项集挖掘算法(Cab-Miner),采用运算栈与检索栈来实现非递归方式的频繁闭项集挖掘,相较于之前普遍采用递归方式的算法,在理论上可使空间占用率由O(L*N+M)降为O(3N)。基于公开数据集与真实数据集的实验表明,上述算法在原始数据集压缩,以及运算内存消耗上,都有较优的表现,尤其在处理真实数据集时,空间表现极佳。另外在某些属性的数据集上也表现出优越的时间效率。

转台运动误差分离与角度优化技术研究

为了解决测量转台运动误差时存在的多种误差耦合问题,提出了一种基于多点法的运动误差分离方法。首先,通过分析转台在回转过程中多自由度误差的运动特性,提出了一种端面四点误差分离方法,在分离出测量盘下表面的平面度误差的同时,可完成倾斜误差和轴向误差的解耦。然后,建立了该方法的误差传递函数,采用麻雀算法(SSA)进行优化,寻找不同阶次下受谐波抑制影响最小的最优布置角,提高了误差解耦精度。最后,通过仿真与实验的方式对该方法进行验证。仿真结果表明,端面四点误差分离方法对轴向、倾斜误差的分离精度(相对误差)分别为1.934%和9.177%。实验结果表明,分离的运动误差与转台标定误差相符合,验证了该方法能够精确获得转台运动误差。

一种求解等圆装箱问题的种群算法

针对等圆装箱问题,基于圆之间的连接表,论文为基于种群的盆地跳跃算法(Population Basin Hopping)提出了一个新的变种。基于连接表的概念,论文为等圆装箱问题提出了一种解之间的距离函数,并根据该距离函数提出了一种新的种群更新策略。通过在规模小于等于100的标准算例上进行优化实验,对所提算法的性能进行了评估。实验结果表明,该算法在解质量和计算速度方面均胜过了文献中已有的最好算法。

勘察报告表格和文本信息提取算法研究

当前,勘察报告作为重要的工程设计依据,其中有大量表格和文本信息未被有效识别利用,为进一步打通专业软件研发的数据壁垒,有效识别和提取勘察报告信息迫在眉睫。针对该现状,本文设计Word表格及文本信息提取算法,并提出信息提取、显示和利用的一整套解决方案。基于文件读写库遍历Word表格,计算每个单元格的行列合并数,进而实现Word表格精准识别至Excel;基于文档自动化技术,记录Word表格范围,反向搜索获取表格标题。基于栈数据结构和匹配算法,遍历Word段落进行大纲匹配和范围计算,实现Word文本大纲信息识别;通过程序后台模拟复制粘贴操作将数据呈现在软件界面上。引入多线程机制,防止勘察报告信息提取操作阻塞主线程,引入并行分析机制,加速文本分析效率,进而提升软件的综合用户体验。以某一实际工程勘察报告为案例进行分析,验证该算法的适用性和准确性。

FAST UPDATE ALGORITHM FOR TCAM-BASED ROUTING LOOKUPS

Routing technology has been forced to evolve towards higher capacity and per port packet processing speed. The ability to achieve high forwarding speed is due to either software or hardware technology. TCAM (Ternary Content Addressable Memory) provides a performance advantage over other software or hardware search algorithms, often resulting in an order of magnitude reduction of search time. But slow updates may affect the performance of TCAM based routing lookup. So the key is to design a table management algorithm, which supports high speed updates in TCAMs. This paper presented three table management algorithms, and then compared their performance. Finally, the optimal one after comparing was given.

A Plant Image Compression Algorithm Based on Wireless Sensor Network

This paper designs and implements an image transmission algorithm applied to plant information collection based on the wireless sensor network. It can effectively reduce the volume of transmitted data, low-energy, high-availability image compression algorithm. This algorithm mainly has two aspects of improvement measures: the first is to reduce the number of pixels that transmit images, from interlaced scanning to interlaced neighbor scanning;the second is to use JPEG image compression algorithm [1], changing the value of the quantization table in the algorithm [2]. After image compression, the image data volume is greatly reduced;the transmission efficiency is improved;and the problem of excessive data volume during image transmission is effectively solved.

Granularity of Knowledge Computed by Genetic Algorithms Based on Rough Sets Theory

Rough set philosophy hinges on the granularity of data, which is used to build all its basic concepts, like approximations, dependencies, reduction etc. Genetic Algorithms provides a general frame to optimize problem solution of complex system without depending on the domain of problem.It is robust to many kinds of problems.The paper combines Genetic Algorithms and rough sets theory to compute granular of knowledge through an example of information table. The combination enable us to compute granular of knowledge effectively.It is also useful for computer auto-computing and information processing.

Interference Cancellation Algorithm for 2×2 MIMO System without Pilot in LTE

Interference cancellation system (ICS) for 3GPP/LTE system is the broadband cancellation system, which receives forward signal through the donor antenna. We proposed new algorithm of received signal with pilot and non-pilot design. Although repeater design needs our project, so in this paper we discuss about interference cancellation algorithm for 2x2 MIMO systems without pilot in LTE. First explain the general principle structure of 3GPP/LTE, next determine our new design and algorithm. Finally, we simulated our mathematic extraction of proposed new algorithm on MATLAB.