AC Line Filter Electrochemical Capacitors:Materials,Morphology,and Configuration

Recently,more and more supercapacitors(SCs)have been developed as AC line filter capacitors,which are generally named AC line filter electrochemical capacitors(FECs).Compared to traditional bulky aluminum electrolytic capacitors(AECs),FECs have higher capacity and lower space occupancy,which makes them a strong competitor.However,different from the common SCs for energy storage,it is necessary to consider the frequency response of the SCs for AC line filtering,where the contradiction between frequency response and specific capacitance is a challenge.The researchers have proposed different solutions from the perspective of materials,morphology,and configuration for this challenge.Based on the above background,in this review,we briefly introduce the principle and parameters of AC line filter electrochemical capacitors.We systematically summarize the state-of-the-art progresses of FECs and discuss their possible application and development in the future.The development of FECs can greatly promote the planarization,integration,and miniaturization of filter capacitors,and provide a new solution for the utilization of green and unstable energy.

A NEW ALGORITHM FOR ADAPTIVE LATTICE FILTERAND ITS APPLICATION IN THE SPEECH LINEARPREDICTIVE SYNTHESIS

In this paper, an adaptive line spectral pair filter is derived from an adaptive lattice filter. A least-mean-square(LMS) type adaptive algorithm used to calculate directly the line spectral pair(LSP) coefficients on a stage-by-stage basis is presented. Experimental results show that the algorithm has higher convergence rate and lower misadjustment as compared with the other algorithms. The LSP coefficients calculated by the algorithm have been used to carry out speech linear predictive synthesis, resulting in better results than PARCOR coefficients.

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.

On the Solution of the Eigenvalue Complementarity Problem by a Line Search Filter-SQP Algorithm

In this paper, the Eigenvalue Complementarity Problem (EiCP) with real symmetric matrices is addressed, which appears in the study of contact problem in mechanics. We discuss a quadratic programming formulation to the problem. The resulting problems are nonlinear programs that can be solved by a line search filter-SQP algorithm.

Design of Miniaturized Band-Pass Filter with Composite Right/Left-Handed Transmission Line

In this paper, a new miniaturized wide-pass-band filter at U band based on composite right/left- handed transmission line (CRLH TL) is implemented. The CRLH TL contributed to a broadband filter is a balanced structure with a small size of only 1.428 mm*0.5530 mm. The frequency characteristics are simulated and the results show that the 3 dB band width of the proposed filter is about 13.5 GHz from 45.8 GHz to 59.3 GHz. The insertion loss is quite flat through the pass-band and the return loss is relatively low.

The Line Shape of Double-Sided Tooth-Disk Waveguide Filters Based on Plasmon-Induced Transparency

We numerically investigate a coupled-resonator structure consisting of a stub resonator and a nanodisk resonator using a two-dimensional finite element method. Simulation results show that plasmon-induced transparency （PIT） occurs in the transmission spectra, and the sharp asymmetric Fano lines increase the sensitivity to 1.4 ×10^3 nm/RIU. We also analyze the properties of the structure with different radii of the nanodisk and the length of the tooth cavity. Moreover, we find that the PIP only happens when the staggered system is around a fixed location with different separate distances, which is not similar to the previous researches. Our model may be important to photonic-integrated circuits and the sensitivity in sensors.

Investigation on Suspended Stripline and End-Coupled Bandpass Filter

In this paper, the variational method combined with Green's function is used to analyze the characteristics of suspended, stripline. The result is in good agreement with references. The design of mm-wave end-coupled bandpass filter with suspended substrate is discussed. The computer programs for design of suspended stripline and bandpass filter are established.

基于粒子滤波的on-line boosting目标跟踪算法

基于Haar-like特征的on-line boosting跟踪算法(HBT)把目标跟踪看作是目标与背景的二分类问题,通过在候选区域搜索最大分类置信度的方法得到目标新的位置。但在获取最大置信度时选用的是区域穷举搜索法,当目标过大或者运动速度过快时,很难确保系统的实时性,且易造成跟踪丢失。本文将粒子滤波算法引入HBT目标跟踪框架中,通过建立目标运动模型,并把HBT目标分类置信度与粒子滤波的观测模型结合起来,提出了基于粒子滤波的on-line boosting目标跟踪算法(PFHBT)。与HBT算法相比,本文算法不仅加快了计算速度,而且很好地解决了目标速度过快造成跟踪丢失的问题,保证了系统的实时性和鲁棒性。

非线性方程组的一个不使用罚函数和filter的算法

给出了求解非线性方程组的一个新算法,首先将非线性方程组转化为一个非线性规划,再使用一个不使用罚函数和filter的算法求解这个非线性规划,在Jacobi矩阵一致列满秩的条件下证明由算法产生序列的极限点是非线性方程组的解.通过在算法中引进二阶校正技术来克服可能的Maratos效应,可以证明这个方法是局部超线性收敛的.

Mitigation of Transients in Capacitor Coupled Substations Using Traditional RLC Filter Techniques

This article presents an extensive examination and modeling of Capacitor Coupled Substations (CCS), noting some of their inherent constraints. The underlying implementation of a CCS is to supply electricity directly from high-voltage (HV) transmission lines to low-voltage (LV) consumers through coupling capacitors and is said to be cost-effective as compared to conventional distribution networks. However, the functionality of such substations is susceptible to various transient phenomena, including ferroresonance and overvoltage occurrences. To address these challenges, the study uses simulations to evaluate the effectiveness of conventional resistor-inductor-capacitor (RLC) filter in mitigating hazardous overvoltage resulting from transients. The proposed methodology entails using standard RLC filter to suppress transients and its associated overvoltage risks. Through a series of MATLAB/Simulink simulations, the research emphasizes the practical effectiveness of this technique. The study examines the impact of transients under varied operational scenarios, including no-load switching conditions, temporary short-circuits, and load on/off events. The primary aim of the article is to assess the viability of using an established technology to manage system instabilities upon the energization of a CCS under no-load circumstances or in case of a short-circuit fault occurring on the primary side of the CCS distribution transformer. The findings underscore the effectiveness of conventional RLC filters in suppressing transients induced by the CCS no-load switching.

微带交指带通滤波器小型化结构设计

文中提出在终端短路式交指带通滤波器的开路端引入一段微带加载线,使谐振器产生尺寸跳变。通过改变微带加载线的线宽,增加谐振器的等效电感值,从而实现降低该带通滤波器中心频率的目的,并且给出了在设计指标下,随加载线宽变化中心频率变化的经验公式。对X波段的微带交指带通滤波器和微带线尺寸跳变进行了研究,研究数据表明:谐振器越短,中心频率往高频偏移越多;微带线尺寸跳变越大,中心频率往低频偏移越多。通过合理减小谐振器长度和增加微带加载线线宽,滤波器整体长度减小而宽度不变,且改进前后滤波特性不发生改变,达到了滤波器小型化的目的。通过在HFSS中建立滤波器模型并进行仿真,改进后增加了传输零点,回波损耗更加稳定,谐振器长度减小10%,微带加载线线宽增加0.15 mm,整体滤波器尺寸减小10%,验证了所提出结构的可行性。

基于Guided Filter的地形图中线要素提取算法

针对彩色扫描地形图中线要素与背景要素难以分离,现有线要素提取算法提取的结果中存在边界不准确的问题,提出基于Guided Filter的地形图中线要素提取算法。利用基于能量密度和Shear变换相结合的线要素提取算法对线要素进行粗提取;引入Guided Filter,以源地形图图像作为Guided Filter的引导图像,以粗提取的线要素图像作为Guided Filter的输入图像,经过滤波处理获得的线要素信息更为显著;利用OTSU算法得到最终的线要素信息。实验结果表明:相对于现有的线要素提取算法,提出的算法能够更为准确地提取出地形图中的线要素,并具有更好的噪声抑制能力。

Performance evaluation of the backprojection filtered (BPF) algorithm in circular fan-beam and cone-beam CT

In this article we introduce an exact backprojection filtered (BPF) type reconstruction algorithm for cone-beam scans based on Zou and Pan’s work. The algorithm can reconstruct images using only the projection data passing through the parallel PI-line segments in reduced scans. Computer simulations and practical experiments are carried out to evaluate this algorithm. The BPF algorithm has a higher computational efficiency than the famous FDK algorithm. The BPF algorithm is evaluated using the practical CT projection data on a 450 keV X-ray CT system with a flat-panel detector (FPD). From the practical experiments, we get the spatial resolution of this CT system. The algo- rithm could achieve the spatial resolution of 2.4 lp/mm and satisfies the practical applications in industrial CT inspec- tion.

一种基于Edline线特征的车道线识别算法

为了提升车道线检测的准确性和实时性,改良车道偏离预警系统的性能,提出了一种新的车道线识别算法。首先应用投影法对采集到的图像设立感兴趣区域,以此来减少图像中存在的干扰信息;其次应用一种改进后的自适应高斯滤波算法对采集所得图像进行平滑处理,减少图像中不必要的细节;最后采用边缘绘制算法进行边缘检测,在此基础上,提出一种线段检测算法——Edline算法提取边缘线,对检测到的直线段进行筛选和聚类。利用引用计数法对车道线进行跟踪和预测。结果表明,新算法的平均处理时间为17.1 ms,准确率为96.19%,将其应用在车道偏离预警系统中可以有效地提高预警效率,提升预警的准确性和响应速度。研究结果丰富了车道线识别理论,可为车道偏离预警系统的应用及基础研究提供参考。

Doppler radar by using single multicarrier pulse based on optical fibre delay lines

The proposed Doppler measurement technique shows that the Doppler measurements can be accomplished by a single pulse with multiple frequency components through optical fibre delay lines.Range and velocity ambiguity can be removed,and the velocity resolution can be improved dramatically by using long optical fibre delay lines.Furthermore,the velocity resolution can be modified by adjusting the length of optical fibre delay lines.In addition,the proposed radar can achieve high range resolution by using a single wideband pulse.As a result,the new approach can improve radar performance significantly.

Novel Control Strategy for Multi-Level Active Power Filter without Phase-Locked-Loop

Active power filter (APF) using novel virtual line-flux-linkage oriented control strategy can not only realizes no phase-locked-loop (PLL) control, but also achieves a good inhibitory effect to interfere. However, there are some problems in the conventional method, such as the error of amplitude, the shift of phase angle and the non-determinacy of initial oriented angle. In this paper, two one-order low-pass filters are adopted instead of the pure integrator in the virtual line-flux-linkage observer, which can steady the phase and amplitude. Furthermore, an original scheme of harmonics detection under the rotating coordinate is advanced based on the simplified space vector pulse width modulation (SVPWM) strategy. Meanwhile, by using the new SVPWM algorithm, the voltage space vector diagram of the three-level inverter can be simplified and applied into that of two-level inverter, and this makes the control for Neutral Point potential easier.

Phase-Locked Loop Based Cancellation of ECG Power Line Interference

Power line(PL)interference is one significant artifact in electrocardiography(ECG)that needs to be reduced to ensure accurate recording of cardiac signals.Because PL interference is non-stationary and has varying frequency,phase,and amplitude in ECG measurement,adaptive techniques are often necessary to track and cancel the interference.In this paper we present a phase-locked loop(PLL)-based adaptive filter to cancel PL interference.The PLL obtains the reference signal that is fed into the adaptive filter to remove the PL interference at the central frequency of 50 Hz.It is found that the technique can effectively cancel PL interference in real ECG signals and,when compared with some existing techniques such as least mean squares(LMS)adaptive filter,the new technique produces better results in terms of signal-to-interference ratio(SIR).

基于直线段检测和LT描述符的矿井图像线特征匹配算法

图像匹配是同步定位与地图构建(SLAM)技术中极为重要的一环,用于根据图像之间的变换关系确定相机位姿。基于线特征的图像匹配方法具有较强的鲁棒性和抗噪能力,更加适用于井下图像匹配,基于深度学习的线描述符对线段遮挡等场景具有较高的鲁棒性,性能优于传统描述符,但卷积神经网络架构的描述符将可变长度线段抽象为固定维进行描述,不利于线段长度及视差变化较大图像的匹配。针对上述问题,提出一种基于直线段检测和线描述符的矿井图像线特征匹配算法。在频域利用单参数同态滤波降低图像的照射分量,并增强反射分量,提升亮度及对比度;在YUV空间利用对比度受限的自适应直方图均衡化(CLAHE)算法对亮度分量进行均衡,使亮度分布更加均匀;变换至RGB空间提取直线段检测(LSD)线,引入一种基于Transformer架构的LT描述符构建LSD线的特征向量,最后完成线特征匹配。实验结果表明:该算法结合了同态滤波和CLAHE算法的优点,增强后图像的亮度适中,对比度良好,灰度分布均匀,增强效果优于单参数同态滤波算法、EnlightenGAN算法;该算法提取的线特征数较原图平均提升了32.92%,在不同相似纹理占比、不同程度旋转与平移变化的井下图像匹配中鲁棒性好,平均正确匹配数为61.75对,平均精度为86.83%,优于线二进制描述符(LBD)算法、LBD_NNDR算法、LT算法,能够满足矿井图像稳健匹配的需求。

基于改进SHKF算法的UWB/IMU组合定位方法

针对复杂环境下超宽带(UWB)无线定位系统存在非视距(NLOS)及随机误差的问题,提出一种基于改进Sage-Husa卡尔曼滤波算法(SHKF)的UWB/IMU组合定位方法。首先,设计了一种基于概率密度的提升树,将UWB/IMU特征数据的概率分布密度引入提升树的损失函数中,鉴别出NLOS信号;然后,设计了一种改进SHKF算法,根据新息变化趋势定义自适应因子,实时调整对新息误差修正的策略以调节历史噪声对当前定位的影响,进而提升UWB/IMU组合定位的稳定性和精度。实验结果表明,所提方法将NLOS信号鉴别精度提升至99.12%,定位均方根误差降低至4.30 cm,提升了复杂环境下UWB/IMU组合系统定位精度。

基于倒L型匹配衰减器的宽带PLC信号阻抗匹配

针对窄带电力线通信(powerline communication, PLC)数据传输速率低、负载阻抗不匹配导致信号反射的问题,提出一种基于倒L型匹配衰减器的宽带PLC阻抗匹配方法。首先,基于归一化低通滤波器的频率变换、阻抗变换和电路变换方法,设计实现了三阶巴特沃斯T型宽带带通滤波模块。然后,采用倒L型结构的纯电阻匹配网络,通过确定不同频点的阻抗值调整主干匹配网络中可变电阻元件,实现了PLC耦合器与电力线之间的阻抗匹配。最后,根据提出的阻抗匹配方法设计制作了具有1~30 MHz带宽的PLC耦合电路。ADS仿真和实测验证均表明,所提阻抗匹配方法在更宽的频率范围内具备良好的匹配效果和电路参数易调节的特点,为PLC阻抗匹配的设计提供了新的理论和实践依据。