Performance evaluation on field synergy and composite regeneration by coupling cerium-based additive and microwave for a diesel particulate filter

In order to reveal the mechanics of composite regeneration by coupling cerium-based additive and microwave for a diesel particulate filter, a composite regeneration model by coupling cerium-based additive and microwave for a diesel particulate filter was established based on field synergy theory. Performance evaluation on field synergy and composite regeneration of the diesel particulate filter was conducted by using the vortex crushing combustion and field synergy mathematical models. The results show that the peak temperature of the particulate filter body reaches 1180-1190 K when the regeneration time is 175 s, and there are optimal coordination degree between the velocity vector and temperature gradient of the filter body and the maximum ratio0.56-0.60 of the best burning regeneration region is obtained. Accordingly, the largest regeneration combustion rate inside the particulate filter body and the highest regeneration efficiency at the moment are achieved.

A New Design Method for Variable Digital Filter Based on Field Programmable Gate Array(FPGA)

In order to obtain variable characteristics,the digital filter's type,number of taps and coefficients should be changed constantly such that the desired frequency-domain characteristics can be obtained.This paper proposes a method for self-programmable variable digital filter(VDF) design based on field programmable gate array(FPGA).We implement a digital filter system by using custom embedded micro-processor,programmable finite impulse response(P-FIR) macro module,coefficient-loader,clock manager and analog/digital(A/D) or digital/analog(D/A) controller and other modules.The self-programmable VDF can provide the best solution for realization of digital filter algorithms,which are the low-pass,high-pass,band-pass and band-stop filter algorithms with variable frequency domain characteristics.The design examples with minimum 1 to maximum 32 taps FIR filter,based on Modelsim post-routed simulation and onboard running on XUPV5-LX110T,are provided to demonstrate the effectiveness of the proposed method.

Algorithm of far-field centre estimation based on phase-only matched filter

Estimation of the far-field centre is carried out in beam auto-alignment. In this paper, the features of the far-field of a square beam are presented. Based on these features, a phase-only matched filter is designed, and the algorithm of centre estimation is developed. Using the simulated images with different kinds of noise and the 40 test images that are taken in sequence, the accuracy of this algorithm is estimated. Results show that the error is no more than one pixel for simulated noise images with a 99% probability, and the stability is restricted within one pixel for test images. Using the improved algorithm, the consumed time is reduced to 0.049 s.

基于改进型Bloom Filter的网络流抽样算法

提出了一种基于改进型Bloom Filter的网络流等概率抽样算法,算法运用对两层位向量的判定结果取交集的方式对到来的数据分组进行判定,将不同位向量的装载因子上限动态设置,通过误差吸收模块和随机抽样模块最终实现对网络流的等概率抽样。实验表明:新算法可以有效减少对网络流的重复抽样,所得结果更加趋近于网络流真实值,节省了系统的存储资源,可以满足当前的高速网络环境。

Fieldline现场总线在袋式除尘器清灰控制系统中的应用

简要介绍工业企业烟气排放控制的重要性及除尘器的作用,详细描述袋式除尘器清灰系统工艺流程,分析现有清灰控制方式的劣势,有针对性地提出了基于Fieldline现场总线的清灰控制系统解决方案。

FPGA-Based Efficient Programmable Polyphase FIR Filter

The modelling, design and implementation of a high-speed programmable polyphase finite impulse response (FIR) filter with field programmable gate array (FPGA) technology are described. This FIR filter can run automatically according to the programmable configuration word including symmetry/asymmetry, odd/even taps, from 32 taps up to 256 taps. The filter with 12 bit signal and 12 bit coefficient word-length has been realized on a Xilinx VirtexⅡ-v1500 device and operates at the maximum sampling frequency of (160 MHz.)

Gabor Filter Optimization Design for Iris Texture Analysis

This paper deals with an optimization design method for the Gabor filters based on the analysis of an iris texture model. By means of analyzing the properties of an iris texture image, the energy distribution regularity of the iris texture image measured by the average power spectrum density is exploited, and the theoretical ranges of the efficient valued frequency and orientation parameters can also be deduced. The analysis shows that the energy distribution of the iris texture is generally centralized around lower frequencies in the spatial frequency domain. Accordingly, an iterative algorithm is designed to optimize the Gabor parameter field. The experimental results indicate the validity of the theory and efficiency of the algorithm.

Backscattering Light Model of Seawater for Modulated Lidar Based on the Stationarity of Light Field

The backscattering signal, which arises from the pulsed laser traveling through water, has limited the lidar system sensitivity and underwater target contrast. The transmitted optical carrier is modulated to be ultrashort pulsed laser and it is effective to suppress the backscattering to adopt the coherent detection technology by identifying the modulation envelope. A nonstationary light field is formed in seawater by the ultrashort pulsed laser. The inherent relationship between the nonstationary light field formed by modulated lidar and the stationary light field formed by conventional lidar was discussed and the backscattering light model of the stationary light field for the ultrashort pulsed laser was proposed. The backscattering signal in modulated lidar system was processed and analyzed in the frequency domain on the basis of the model.

J-Resolution Fields of Generalized Literals of L_(14)P(X)

To deal with automated reasoning of linguistic truth-valued lattice-valued logic system, a lattice implication algebra with 14 elements, L14, was defined, and the J-resolution fields of constants, propositional variables and some generalized literals of L14P（X）, which is a lattice-valued propositional logic system with truth-values in L14, were discussed. There are 4 filters in L14. For any constant a not belonging to J, a and g （generalized literal of L14P（X）） form a J-resolution pair. For a propositional variable x, if x belongs to J and g does not belong to J, then x and g form a J-resolution pair.

Optimized Implementation for Wave Digital Filter Based Circuit Emulation on FPGA

A binary tree representation is designed in this paper for optimization of wave digital filter（WDF）implementation.To achieve this,an equivalent WDF model of the original circuit is converted into abinary tree representation at first.This WDF binary tree can then be transformed to several topologies with the same implication,since the WDF adaptors have a symmetrical behavior on their ports.Because the WDF implementation is related to field programmable gate array（FPGA）resource usage and the cycle time of emulation,choosing aproper binary tree topology for WDF implementation can help balance the complexity and performance quality of an emulation system.Both WDF-FPGA emulation and HSpice simulation on the same circuit are tested.There is no significant difference between these two simulations.However,in terms of time consumption,the WDF-FPGA emulation has an advantage over the other.Our experiment also demonstrates that the optimized WDF-FPGA emulation has an acceptable accuracy and feasibility.

Local Orientation Field Based Nonlocal Means Method for Fingerprint Image De-Noising

The de-noising of the fingerprint image is one of the key tasks before the extraction of the minutiae in automatic fingerprint matching. When used for de-noising the fingerprint image, the nonlocal means method can not preserve the local minutiae in the fingerprint image very well. To address this problem, we propose a local orientation field based nonlocal means (NLM-LOF) method in this paper. Experimental results on the simulated and real images show that the proposed method can suppress noise effectively while preserving edges and details in the fingerprint image and it outperforms the state-of-art nonlocal means method in terms of qualitative metrics and visual comparisons.

Theoretical and Experimental Research on the Sound Field in A Finite Duct

Based upon the theoretical analysis of the sound field in a finite duct and the spatialsampling principle,this paper applies the adaptive filtering technique to the measurement of thesound field in the duct with the distribution patterns of standing waves in the direction of thewaveguide and high—order wavefront on the cross section of the duct measured and the acousticmode theory proved by experimental results.

A rapid and convenient experimental method of absolutely calibrating transmission of x-ray flat-response filter

We develop a rapid and convenient experimental method of absolutely calibrating the transmission of an x-ray flatresponse filter. The calibration experiment is performed on a small laser-target facility, and a set of high resolution holographic flat-field grating spectrometers is used as a discrimination system of the laser-produced x-ray source. Given that the holographic flat-field grating has a relatively large width, the grating is divided into two regions for use in that direction,where one region has the filter added and the other region does not. The filter transmission is determined by dividing the x-ray signal counts detected when the filter is in the line of sight by those detected when the filter is out of the line of sight.We find that the calibration results of this experiment agree with the calibration results using a synchrotron radiation source,as well as simulation results. Our method is not only highly reliable but also rapid and convenient.

Ear Field Adaptive Noise Control for Snoring:An Real-time Experimental Approach

In this paper, an active noise control(ANC) system is developed to provide an effective and non-intrusive solution for reducing loud snoring to provide a quiet environment for a snorer's bed partner. An adaptive least mean square(LMS)algorithm optimized for different kinds of snore signals is introduced and theoretically analyzed. Also, a residual noise masking approach is proposed to further reduce the effect of the snore noise without interfering with the LMS algorithm. Computer simulations followed by real-time experiments are conducted to demonstrate the feasibility of the snore ANC systems based on a pillow setup. For the optimum effect based on the characteristics of human hearing, the performance of the proposed approach is evaluated by using the multi-channel feedforward ANC systems based on the filtered-X least mean square(FXLMS) algorithm.Compared with a traditional headboard setup for snoring noise control, the proposed snore ANC systems optimized for ear field operation yield much higher noise reduction around the ears of the snorer's bed partner.

A High Precision Biorthogonal 9/7 Wavelet Filter Implemented in the FPGA

An efficient high precision biorthogonal 9/7 wavelet filter structure for image processing applications was proposed. This structure aimed at high precision applications. A precision improved distributed algorithms (DA) had been proposed. Comparing with traditional DA implementations, the new DA had higher precision while preserves smaller area. The proposed structure was verified in Spartan-6 field programmable gate array (FPGA) and achieved 200 MHz operation frequency. The peak signal to noise ratio (PSNR) of reconstructed image (Lena) achieves 74 dB which is very high comparing with other implementations.

An iterative Wiener filtering method based on the gravity gradient invariants

How to deal with colored noises of GOCE （Gravity field and steady - state Ocean Circulation Explorer） satellite has been the key to data processing. This paper focused on colored noises of GOCE gradient data and the frequency spectrum analysis. According to the analysis results, gravity field model of the optima] degrees 90-240 is given, which is recovered by COCE gradient data. This paper presents an iterative Wiener filtering method based on the gravity gradient invariants. By this method a degree-220 model was calculated from GOCE SGG （Satellite Gravity Gradient） data. The degrees above 90 of ITG2010 were taken as the prior gravity field model, replacing the low degree gravity field model calculated by GOCE orbit data. GOCE gradient colored noises was processed by Wiener filtering. Finally by Wiener filtering iterative calculation, the gravity field model was restored by space-wise harmonic analysis method. The results show that the model＇s accuracy matched well with the ESA＇s （European Space Agency） results by using the same data,

时序数据图像化:战术意图识别及可移植框架

通过将时序编码为图像,提出了一种结合曲线滤波技术和EfficientNetV2图像识别网络的鲁棒且可移植的战术意图识别框架。曲线滤波技术可以有效地减少大量时域特征、模型参数和训练时间的冗余,基于此,提出了一种改进的格拉姆角场方法将时序编码为图像,提高了卷积神经网络的特征提取能力。EfficientNetV2网络能够有效地处理意图图像,并成为预训练模型,使得在不同系统之间进行迁移学习成为可能。实验结果表明,所提框架相对于机器学习及深度学习等方法提高了0.99%以上的准确率,具有更好的性能、可扩展性、鲁棒性和可迁移性。

大视场白光干涉测量系统及性能研究

基于国产化的2倍迈克尔逊型干涉物镜组,优选配置0.5倍适配镜,对白光LED照明光源进行带通滤波参数的仿真估算和实验性能比较,构建了整套大视场白光干涉精密测量装置系统并进行了实验测试,通过白光干涉轴向响应实验曲线确定了中心波长。实验结果表明:通过光谱滤波获得了较为理想的白光干涉轴向响应曲线;系统的水平最大视场达到了14 mm;高度为2.04μm和20.43μm的标准台阶样品的测量结果分别为2.05μm和20.47μm,10次测量重复精度(标准差)分别为12 nm和16 nm。对粗糙度样板、微机电系统传感结构和半导体晶圆膜层进行了实测,表明所研制的系统装置在三维光学无损精密检测领域的应用具有可行性。

大尺度磁性目标跟踪方法研究

针对磁定位中由于目标尺度不可忽略导致的观测模型不匹配问题,提出一种仅需2个三轴磁传感器测量数据,且能够自适应目标尺度的滤波估值型实时磁定位算法。该方法基于最大似然选择思想,建立了不同个数磁偶极子构成的均匀线列阵模型作为候选观测模型;推导了一种适用于高维非线性动态参数估计的随机高斯流滤波算法,克服了大尺度目标模型高维度和强非线性导致的性能下降问题,提高了实时定位精度。同时,采用该算法对各个偶极子线阵模型分别进行滤波解算,选取最大似然值对应的滤波结果作为当前时刻估计值,实现了对目标尺度的自适应。通过双层壳体潜艇有限元磁场仿真模型数据对算法的有效性进行了验证,结果表明,相比现有方法,该算法估值更为准确,能够满足精确实时定位目标的需求,且具有更好的收敛性能。

地电场地铁干扰滤波算法适用性研究

地铁运行对应城地震监测站地电场观测造成显著干扰,其中最大干扰幅度可达33 mV/km,平均干扰幅度约14 mV/km。为改善观测数据质量,对比分析应城地震监测站地电场正常日变化和干扰数据的时频特征,分别采用均值滤波、经验模态分解和数学形态学滤波方法对干扰数据进行滤波处理,并对比分析几种方法的滤波效果,及形态学结构元素的尺度因子对滤波结构的影响。结果表明,使用均值滤波和广义形态学滤波方法,可有效去除地电场地铁干扰,建议受地铁干扰的地电场台站使用以上2种方法对观测数据进行处理,以提升其使用效能。