基于L_(2)灵敏度最小化的数字滤波器状态空间实现稀疏化方法

为解决传统数字滤波器在有限精度实现时因有限字长(Finite Word Length,FWL)效应导致滤波器性能下降的问题,提出一种L_(2)灵敏度最小化的数字滤波器状态空间实现稀疏化方法.推导前向差分算子数字滤波器结构传输函数及其等效状态空间实现,根据可控及可观格莱姆矩阵得到基于相似变换矩阵的L_(2)灵敏度表达式,并进行稀疏化校准,将L_(2)灵敏度最小化问题转换为凸函数求最值问题,求导得到L_(2)灵敏度最小化表达式,代回即得前向差分算子数字滤波器的稀疏化状态空间实现.仿真结果表明,所提方法设计的数字滤波器具有更好的抗FWL效应.

An Optimized Chinese Filtering Model Using Value Scale Extended Text Vector

With the development of Internet technology,the explosive growth of Internet information presentation has led to difficulty in filtering effective information.Finding a model with high accuracy for text classification has become a critical problem to be solved by text filtering,especially for Chinese texts.This paper selected the manually calibrated Douban movie website comment data for research.First,a text filtering model based on the BP neural network has been built;Second,based on the Term Frequency-Inverse Document Frequency(TF-IDF)vector space model and the doc2vec method,the text word frequency vector and the text semantic vector were obtained respectively,and the text word frequency vector was linearly reduced by the Principal Component Analysis(PCA)method.Third,the text word frequency vector after dimensionality reduction and the text semantic vector were combined,add the text value degree,and the text synthesis vector was constructed.Experiments show that the model combined with text word frequency vector degree after dimensionality reduction,text semantic vector,and text value has reached the highest accuracy of 84.67%.

Optical and electrical properties of BaSnO_(3) and In_2O_(3) mixed transparent conductive films deposited by filtered cathodic vacuum arc technique at room temperature

For the crystalline temperature of BaSnO_(3)(BTO)was above 650℃,the transparent conductive BTO-based films were always deposited above this temperature on epitaxy substrates by pulsed laser deposition or molecular beam epitaxy till now which limited there application in low temperature device process.In the article,the microstructure,optical and electrical of BTO and In_(2)O_(3) mixed transparent conductive BaInSnO_(x)(BITO)film deposited by filtered cathodic vacuum arc technique(FCVA)on glass substrate at room temperature were firstly reported.The BITO film with thickness of 300 nm had mainly In_(2)O_(3) polycrystalline phase,and minor polycrystalline BTO phase with(001),(011),(111),(002),(222)crystal faces which were first deposited at room temperature on amorphous glass.The transmittance was 70%–80%in the visible light region with linear refractive index of 1.94 and extinction coefficient of 0.004 at 550-nm wavelength.The basic optical properties included the real and imaginary parts,high frequency dielectric constants,the absorption coefficient,the Urbach energy,the indirect and direct band gaps,the oscillator and dispersion energies,the static refractive index and dielectric constant,the average oscillator wavelength,oscillator length strength,the linear and the third-order nonlinear optical susceptibilities,and the nonlinear refractive index were all calculated.The film was the n-type conductor with sheet resistance of 704.7Ω/□,resistivity of 0.02Ω⋅cm,mobility of 18.9 cm2/V⋅s,and carrier electron concentration of 1.6×10^(19) cm^(−3) at room temperature.The results suggested that the BITO film deposited by FCVA had potential application in transparent conductive films-based low temperature device process.

活性炭吸附低浓度SO_(2)和丙酮的分子模拟研究

随着集成电路线宽的减小,电子工业洁净室中的气态分子污染物呈现出浓度低、种类多的特点。极低分压条件下,气态分子污染物在活性炭基化学过滤器中的竞争吸附机理尚不清楚。本文基于巨正则蒙特卡罗(GCMC)和分子动力学(MD)方法,模拟了不同温度和相对湿度下活性炭对低浓度SO_(2)和丙酮的吸附过程。结果表明:活性炭对SO_(2)和丙酮的吸附量随温度的升高而降低,随相对湿度的增大变化不明显;SO_(2)和丙酮同时存在对活性炭的初始吸附能力没有明显影响。

基于A^(2)/O工艺污水厂改造与提标工程设计

南方某污水厂提标扩建工程,一期A^(2)/O好氧区采用MBBR工艺改造并增大缺氧区容积;二期提标采用高效沉淀池+纤维转盘滤池+紫外消毒工艺,强化脱氮除磷及SS去除,并对全厂进行除臭设计。提标扩建后总规模12×10^(4)m^(3)/d,直接运行成本约0.63元/m^(3),出水均值为COD 17.10 mg/L、BOD55.40 mg/L、SS 5.80 mg/L、NH_(4)^(+)-N 0.90 mg/L、TN 5.90 mg/L、TP 0.30 mg/L。均优于《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级A标准,其经验可供其他污水厂借鉴。

氮掺杂对环境空气中TiO_(2)纳米催化剂抗甲醛光催化矿化的影响

通过氮掺杂TiO_(2)(N-TiO_(2))浸渍蜂窝过滤器构建了一系列原型光催化空气净化器(AP(N_(x)-C_(y)))系统,并用于在UV-LED光(1 W)照射条件下光催化分解0.5-5 ppm甲醛(CH_(2)O)蒸汽.在上述催化过滤器系统中,Nx和Cy分别代表N/Ti摩尔比(0-20)和N-TiO_(2)浓度(2-20 mg mL^(-1)).光催化分解实验结果表明,AP(N_(10)-C_(10))的性能最好,其催化CH2O转化为CO_(2)的转化率最高,循环反应10次后CO_(2)产率仍达到89.2%,在干燥空气中的清洁空气输送速率为9.45 L min^(-1).N10-C10的电荷载流子寿命(τa:1.70 ns)优于其他样品(如纯TiO_(2)的电荷载流子寿命为1.37 ns),这表明N缺陷(No)有助于降低带隙(3.10 eV)和产生氧空位OVs-Ti^(3+),这与密度泛函理论(DFT)模拟结果一致.采用原位漫反射红外傅里叶变换、电子顺磁共振和DFT分析等多种方法研究了CH_(2)O的光催化氧化途径.结果表明,氧化过程涉及多个能量有利的中间步骤(例如CH2O以CH_(2)O_(2)的形式在TiO_(2)-OV{110}表面的桥连O/OH基团上发生放热共价吸附,随后通过催化脱氢/氧化反应直接生成CO_(2):CH_(2)O_(2)/HCOO^(-)+•OH→H_(2)O+CO_(2)).这些步骤与具有N杂质的{101}表面上化学活性Ti原子的态密度计算结果一致.预计No缺陷和OVs的存在将通过降低活化能垒来影响反应能量和中间产物,从而在加湿条件下实现有效的矿化.综上,本文为设计和构建先进的光催化系统,并用于环境空气中醛类挥发性有机物(VOCs)的有效矿化提供了新思路.

面向组合惯性导航系统的χ^(2)故障检测与诊断

文章主要对组合导航系统中的χ^(2)故障及其诊断进行研究。将该系统基本的误差模型作为依据,针对其故障诊断,提出了在联邦滤波结构中适用的故障监测技术,即通过联邦滤波结构中的残差检验技术来检测该系统里的硬故障,将没有故障情况下的最优全局估计信息构造滑动残差用作检验标准,来检测该系统中的软故障,并将软故障检测函数作为依据,自适应调节信息分配系数。经实验发现,本次所提出的算法在此类故障检测及其诊断中十分适用。

基于2D-Gabor与KLDA的特征提取

提出一种2D-Gabor小波与核线性鉴别分析(KLDA)相结合的特征提取方法。该方法对经过预处理的人脸图像进行多方向、多尺度的2D-Gabor滤波,将滤波后的图像看作独立样本加入原样本库中,对新样本利用KLDA方法进行二次特征提取,得到较理想的类内聚度和类间散度样本特征,再采用三阶近邻分类器进行特征分类处理。实验结果表明,该方法相比传统方法识别率更高,易于工程实现。

基于2D-Gabor滤波器的虹膜识别算法实现

利用虹膜图像中丰富的结构和纹理特征作为身份鉴别的依据,与其他生物特征识别相比,具有更高的可靠性。根据虹膜内外灰度差,采用二值化方法提取瞳孔,用Canny算子精确定位虹膜的内边缘,利用微分积分算子定位外边缘,并对虹膜进行归一化、校准、增强等预处理;再利用2D-Gabor滤波提取纹理特征,最后比较Hamming距离,进行匹配与识别。实验结果表明,该方法效果良好,识别率高。

基于Bloom Filter和概率分发队列的P2P网络快速查找算法

无结构化P2P网络资源定位过程中的响应时间、查准率及覆盖率难以同时被优化。提出一种面向有向无环随机网络的基于Bloom Filter和概率分发队列的快速查找算法BFPDQ(Bloom Filter and Probabilistic Distribution Queue),它用Bloom Filter表达和传递节点命中资源信息及查找请求信息,计算新查询消息与历史查询消息Bloom Filter语义向量相似度,并应用底层网络路径性能信息指导上层转发决策。概率分发队列(Probabilistic Distribution Queue,PDQ)把传统walkers表示成为查找消息分发队列,查找请求者协调各分发队列的查找方向和深度,并融合各队列查找过程中得到的定位消息。仿真实验表明,BFPDQ算法在保持较少冗余信息的同时有效缩短了响应时间。

基于自适应H_(2)/H_(∞)滤波的锂电池SOC和SOH联合估计

准确、实时地估计电池的荷电状态(state of charge,SOC)和健康状态(state of health,SOH)是现代电池管理系统的关键任务。通过自适应H_(2)/H_(∞)滤波器可对锂电池的SOC和SOH进行联合估计。该方法基于锂电池的二阶RC等效电路模型,采用AFFRLS法在线辨识锂电池的模型参数,并利用H_(2)/H_(∞)滤波器估计锂电池的SOC,AFFRLS辨识与H_(2)/H_(∞)滤波交替进行,得到一种自适应H_(2)/H_(∞)滤波器。SOH依据AFFRLS辨识的电池内阻进行估计,实现了锂电池SOC与SOH的联合估计。实验结果表明:自适应H_(2)/H_(∞)滤波算法的估计精度高且鲁棒性强,电池的SOC和SOH的平均估计误差始终保持在±0.19%以内,相比于EKF和H_(∞)滤波算法有更高的估计精度与稳定性。

Electrically triggered dual-band tunable terahertz metamaterial band-pass filter based on Si_3N_4–VO_2–Si_3N_4 sandwich

We experimentally demonstrate an electrically triggered terahertz(THz) dual-band tunable band-pass filter based on Si_3 N_4–VO_2–Si_3 N_4 sandwich-structured hybrid metamaterials. The insulator–metal phase transition of VO_2 film is induced by the Joule thermal effect of the top metal layer. The finite-integration-time-domain(FITD) method and finite element method(FEM) are used for numerical simulations. The sample is fabricated using a surface micromachining process,and characterized by a THz time-domain-spectrometer(TDS). When the bias current is 0.225 A, the intensity modulation depths at two central frequencies of 0.56 THz and 0.91 THz are about 81.7% and 81.3%, respectively. This novel design can achieve dynamically electric–thermo–optic modulation in the THz region, and has potential applications in the fields of THz communications, imaging, sensing, and astronomy exploration.

基于查询内容Bloom Filter的P2P网络路由机制

为减少洪泛路由的盲目性,提出并验证了一种根据查询请求内容的不同来选择不同节点,进行查询转发的路由改进机制。节点保存描述已知节点资源的Bloom filter,按查询内容的匹配程度选择转发查询的邻居节点。实验表明,该机制可以减少消息冗余,提高路由效率,提高P2P系统的可扩展性。

Filter badge SO_2捕集-离子色谱法测定空气中二氧化硫

用Filter badge SO2捕集空气中SO2。用双氧水将捕集到的SO2氧化成SO42-,再用离子色谱法测定SO42-的浓度,按公式f SO2=2082×103×(T/τ)X计算,即可得到捕集时间内的平均SO2浓度f SO2(ppb)。

Distributed H2/H∞ Filter Design for Discrete-Time Switched Systems

This paper addresses an infinite horizon distributed H2/H∞ filtering for discrete-time systems under conditions of bounded power and white stochastic signals. The filter algorithm is designed by computing a pair of gains namely the estimator and the coupling. Herein, we implement a filter to estimate unknown parameters such that the closed-loop multi-sensor accomplishes the desired performances of the proposed H2 and H∞ schemes over a finite horizon. A switched strategy is implemented to switch between the states once the operation conditions have changed due to disturbances. It is shown that the stability of the overall filtering-error system with H2/H∞ performance can be established if a piecewise-quadratic Lyapunov function is properly constructed. A simulation example is given to show the effectiveness of the proposed approach.

Effects of ZnCl2/H2O/C2H5OH Treatment on the Filter Paper Performance

Bleached softwood kraft pulp (BSKP) fibers were pretreated in a 5 mol/L NaOH aqueous solution at 35℃ for 90 min. The ZnCl2/H2O/ C2H5OH was used to treat the pretreated BSKP fibers, filter papers were then prepared. In the course of processing, the effects of various molar ratios of ZnCl2/H2O/C2H5OH on the filter paper performance were evaluated. SEMEDX was conducted to analyze the physical configuration of the filter papers. Moreover, FT-IR and XPS were performed to further characterize the BSKP, the pretreated BSKP and the filter paper fibers. The results indicated that the fibers treated by ZnCl2/H2O/C2H5OH were swollen and exhibited slight fibrillation, leading to a looser fiber structure and therefore, enhanced filter paper performance. Air permeability increased from 161.7 L/(m2·s) to 1450.4 L/(m2·s) for the filter papers when the molar ratio of ZnCl2/H2O/C2H5OH was 1:14:1. The optimum molar ratio of ZnCl2/H2O/C2H5OH was found to be 1:14:1, and no significant effect of ZnCl2/H2O/C2H5OH on fibers’ functional groups was detected. These results showed that filtration performance of filter papers was improved when treated with the ZnCl2/H2O/C2H5OH solution.

Kalman Filter for Generalized 2-D Roesser Models

The design problem of the state filter for the generalized stochastic 2-D Roesser models, which appears when both the state and measurement are simultaneously subjected to the interference from white noise, is discussed. The well-known Kalman filter design is extended to the generalized 2-D Roesser models. Based on the method of “scanning line by line”,the filtering problem of generalized 2-D Roesser models with mode-energy reconstruction is solved. The formula of the optimal filtering, which minimizes the variance of the estimation error of the state vectors, is derived. The validity of the designed filter is verified by the calculation steps and the examples are introduced.

亚像素图像ContourExtractor2DimageFilter算法研究

随着实时图像、超大图像处理的需求增加,图像的轮廓提取已成为计算机视觉处理中的重要环节。本文研究了一种亚象素轮廓高速提取算法,对其算法总则进行了概括,对算法方法进行了描述,并基于该算法进行了实验,对其算法效率进行了分析,取得良好的效果。

A^(2)/O-BAF工艺短程硝化模式下反硝化除磷效能

采用厌氧/缺氧/好氧-曝气生物滤池(A^(2)/O-BAF)工艺处理低C/N城市污水,研究硝化液回流比为0、50%、100%、150%和200%时该工艺脱氮除磷效能。结果表明,在A^(2)/O中控制污泥龄(SRT)为15d,水力停留时间(HRT)为10h,好氧段溶解氧(DO)为2.0mg/L;BAF中控制HRT为3h、好氧/缺氧曝停时间比为50min∶10min以及硝化液回流比R=200%的条件下,进水COD、TN、NH_(4)^(+)-N和PO_(4)^(3-)-P的浓度分别为232.61mg/L、53.99mg/L、52.20mg/L和5.54mg/L,系统出水中COD、TN、NH_(4)^(+)-N和PO_(4)^(3-)-P的浓度分别为34.11mg/L、12.44mg/L、1.01mg/L和0.34mg/L,亚硝积累率(Ni AR)高达95.20%。出水NO_(2)^(-)-N回流至A^(2)/O缺氧段后,缺氧段出水的PO_(4)^(3-)-P含量下降至2.68mg/L,反硝化除磷(DPR)对系统PO_(4)^(3-)-P的去除贡献达75.42%。批次试验表明,A^(2)/O反应器中的除磷菌在厌氧120min后释磷量达到36.35mg/L,缺氧条件下以NO_(2)^(-)-N为电子受体的反应中吸磷量为26.28mg/L,吸磷率为72.30%,以NO_(2)^(-)-N为电子受体的反硝化除磷菌(DPB)占总除磷菌的72.91%。

Nonstationary Filtering for Markov Jumping Systems with Fading Channel and Multiplicative Noises

This paper studies the nonstationary filtering problem of Markov jump system under l2 - l∞ performance. Due to the difference in propagation channels, signal strength and phase will inevitably change randomly and cause the waste of signals resources. In response to this problem, a channel fading model with multiplicative noise is introduced. And then a nonstationary filter, which receives signals more efficiently is designed. Meanwhile Lyapunov function is constructed for error analysis. Finally, the gain matrix for filtering is obtained by solving the matrix inequality, and the results showed that the nonstationary filter converges to the stable point more quickly than the traditional asynchronous filter, the stability of the designed filter is verified.