Error correction of digital signal processing devices using non-positional modular codes

The paper discusses an algorithm for correcting code errors of the residue number system using a positional characteristic. Application of parallel-pipeline computations of this positional characteristic allows us to reduce hardware costs by 7.2% for processing 2-byte data represented in a residue number system code. The main properties of codes allow us to provide the required fault-tolerance for multi-rate DSP devices. The results provided in the paper can be applied to hydroacoustic monitoring tasks.     

用MAX7000A实现多普勒信号数字信号处理的分析与线路设计

本文以连续波多普勒无线电引信为研究背景,建立目标信号数学模型,针对目前炸高控制方法及存在问题,提出了一种新的多普勒脉宽技术测高方法,在此基础上增加一个近表面炸的性能。并介绍了采用可编程逻辑器件实现的方法以及计算机仿真。实践证明,对Ｄｏｐｐｌｅｒ信号的数字信息处理,用一片ＣＰＬＤ实现,提高引信信号处理的速度,并极大提高了系统的可靠性。     

Order-configuration functions: Mathematical characterizations and applications to digital signal and image processing

We call a function f in n variables an order-configuration function if for any x₁,…, x_n such that x_i1 … x_in we have f(x₁,…, x_n) = x_t, where t is determined by the n-tuple (i₁,…, i_n) corresponding to that ordering. Equivalently, it is a function built as a minimum of maxima, or a maximum of minima. Well-known examples are the minimum, the maximum, the median, and more generally rank functions, or the composition of rank functions. Such types of functions are often used in nonlinear processing of digital signals or images (for example in the median or separable median filter, min-max filters, rank filters, etc.). In this paper we study the mathematical properties of order-configuration functions and of a wider class of functions that we call order-subconfiguration functions. We give several characterization theorems for them. We show through various examples how our concepts can be used in the design of digital signal filters or image transformations based on order-configuration functions.     

LabVIEW在数字信号处理教学中的应用

针对数字信号处理教学的现状和存在的问题及LabVIEW软件的功能,提出了将LabVIEW应用于数字信号处理的教学中。并以滤波器设计与帕塞瓦尔定理验证的LabVIEW辅助教学为例,指出将LabVIEW运用于数字信号处理教学中的优点和该方法的可行性。     

Design of MAC unit for digital filters in signal processing and communication

International Journal of Speech Technology - Digital signal processors (DSP) the endless requirement is the development of ability in processors to hold the difficulties resulted in the...     

HD-SDI数字视频信号处理及传输的FPGA设计与实现

设计了一种符合SMPTE292M标准的高清晰度数字电视信号采集传输用的HD-SDI卡,介绍了其电路结构,对HD-SDI中的视频数据、视频定时基准码、行号数据、校验码进行了分析,并就数字视频识别和提取模块、DMA传输模块和PLX9656局部总线到Avalon总线的转换模块进行了设计.FPGA采用Altera公司的Stratix EP1S25,实验调试结果表明,HD-SDI数字视频信号处理及传输工作稳定可靠.     

可编程FIR滤波器PDSP16256在数字信号处理中的应用

介绍高集成度、高速、高精度、可应用在高性能数字信号处理系统中的可编程ＦＩＲ滤波器ＰＤＳＰ１６２５６芯片的结构、特点、性能以及系数加载方式和控制寄存器的设置，并给出了ＰＤＳＰ１６２５６在雷达信号处理器数字脉冲压缩中的应用实例     

HD SDI数字视频信号处理及传输的FPGA设计与实现*

设计了一种符合SMPTE292M标准的高清晰度数字电视信号采集传输用的HDSDI卡,介绍了其电路结构,对HDSDI中的视频数据、视频定时基准码、行号数据、校验码进行了分析,并就数字视频识别和提取模块、DMA传输模块和PLX9656局部总线到Avalon总线的转换模块进行了设计。FPGA采用Altera公司的Stratix EP1S25,实验调试结果表明,HDSDI数字视频信号处理及传输工作稳定可靠。     

Applying linear interaction energy method for binding affinity calculations of podophyllotoxin analogues with tubulin using continuum solvent model and prediction of cytotoxic activity

Podophyllotoxin and its analogues have important therapeutic value in the treatment of cancer, due to their ability to induce apoptosis in cancer cells in a proliferation-independent manner. These ligands bind to colchicine binding site of tubulin near the α- and β-tubulin interface and interfere with tubulin polymerization. The binding free energies of podophyllotoxin-based inhibitors of tubulin were computed using a linear interaction energy (LIE) method with a surface generalized Born (SGB) continuum solvation model. A training set of 76 podophyllotoxin analogues was used to build a binding affinity model for estimating the free energy of binding for 36 inhibitors (test set) with diverse structural modifications. The average root mean square error (RMSE) between the experimental and predicted binding free energy values was 0.56 kcal/mol which is comparable to the level of accuracy achieved by the most accurate methods, such as free energy perturbation (FEP) or thermodynamic integration (TI). The squared correlation coefficient between experimental and SGB–LIE estimates for the free energy for the test set compounds is also significant (R² = 0.733). On the basis of the analysis of the binding energy, we propose that the three-dimensional conformation of the A, B, C and D rings is important for interaction with tubulin. On the basis of this insight, 12 analogues of varying ring modification were taken, tested with LIE methodology and then validated with their experimental potencies of tubulin polymerization inhibition. Low levels of RMSE for the majority of inhibitors establish the structure-based LIE method as an efficient tool for generating more potent and specific inhibitors of tubulin by testing rationally designed lead compounds based on podophyllotoxin derivatization.     

Applying linear interaction energy method for binding affinity calculations of podophyllotoxin analogues with tubulin using continuum solvent model and prediction of cytotoxic activity

Podophyllotoxin and its analogues have important therapeutic value in the treatment of cancer, due to their ability to induce apoptosis in cancer cells in a proliferation-independent manner. These ligands bind to colchicine binding site of tubulin near the α- and β-tubulin interface and interfere with tubulin polymerization. The binding free energies of podophyllotoxin-based inhibitors of tubulin were computed using a linear interaction energy (LIE) method with a surface generalized Born (SGB) continuum solvation model. A training set of 76 podophyllotoxin analogues was used to build a binding affinity model for estimating the free energy of binding for 36 inhibitors (test set) with diverse structural modifications. The average root mean square error (RMSE) between the experimental and predicted binding free energy values was 0.56 kcal/mol which is comparable to the level of accuracy achieved by the most accurate methods, such as free energy perturbation (FEP) or thermodynamic integration (TI). The squared correlation coefficient between experimental and SGB–LIE estimates for the free energy for the test set compounds is also significant (R² = 0.733). On the basis of the analysis of the binding energy, we propose that the three-dimensional conformation of the A, B, C and D rings is important for interaction with tubulin. On the basis of this insight, 12 analogues of varying ring modification were taken, tested with LIE methodology and then validated with their experimental potencies of tubulin polymerization inhibition. Low levels of RMSE for the majority of inhibitors establish the structure-based LIE method as an efficient tool for generating more potent and specific inhibitors of tubulin by testing rationally designed lead compounds based on podophyllotoxin derivatization.     

Identification of potent virtual leads and ADME prediction of isoxazolidine podophyllotoxin derivatives as topoisomerase II and tubulin inhibitors

Towards the design of new class of podophyllotoxin to target topoisomerase II and tubulin as substantial target in cancer therapy, a series of isoxazolidine podophyllotoxin derivatives were designed. Topoisomerase in complex with etoposide and four β-tubulin in complex with zampanolide, taxol, vinblastine or colchicine were used as targets using GOLD5.2.2 as a docking module. The revealed key structural features of the highest fitness into tubulin domain have been explained as follows: (1) trans orientation of the lactone (ring D) with 5a-β, 8a-α configuration; (2) dioxolane in ring A; (3) free rotation of ring E; (4) α (R) or β (S) configuration has equal fitness in position 5; (5) 4′-OMe; (6) phosphoramide linkage; (7) ethylene bridge between the phosphate and isoxazolidine ring; (8) benzyl moiety at N²-position of isoxazolidine ring; and (9) position 5 of isoxazolidine ring accommodated with 6-bromo-9H-purine, 2-amino-6H-purin-6-one, or N-(2-oxopyrimidin-4-yl) acetamide. All of these structural features are applicable for compounds to fit properly into topoisomerase II, except (1) β (S) configuration has a higher score fitness than α (R) in position 5; (2) 4′-OH; and (3) position 5 of isoxazolidine ring accommodated better with 6-bromo-9H-purine, 2-amino-6H-purin-6-one or 7H-purin-6-amine. Computational ADMET and toxicity studies were in consensus with the docking results. Compounds holding ethylene bridge between phosphate and benzyl moiety at N²-position of isoxazolidine ring have the optimal pharmacokinetic properties and were calculated to be non-toxic. The predicted solubility profile for most of 4′-OMe containing compounds was good. This accomplished our aim in identifying promising new hits as antitumor agent with improved activity and less toxicity.     

Compressed-sensing recovery of multiview image and video sequences using signal prediction

In the compressed sensing of multiview images and video sequences, signal prediction is incorporated into the reconstruction process in order to exploit the high degree of interview and temporal correlation common to multiview scenarios. Instead of recovering each individual frame independently, neighboring frames in both the view and temporal directions are used to calculate a prediction of a target frame, and the difference is used to drive a residual-based compressed-sensing reconstruction. The proposed approach demonstrates a significant gain in reconstruction quality relative to the straightforward compressed-sensing recovery of each frame independently of the others in the multiview set, as well as a significant performance advantage as compared to a pair of benchmark multiple-frame compressed-sensing reconstructions.     

InCa-SiteFinder: A method for structure-based prediction of inositol and carbohydrate binding sites on proteins

Carbohydrate binding sites are considered important for cellular recognition and adhesion and are important targets for drug design. In this paper we present a new method called InCa-SiteFinder for predicting non-covalent inositol and carbohydrate binding sites on the surface of protein structures. It uses the van der Waals energy of a protein–probe interaction and amino acid propensities to locate and predict carbohydrate binding sites. The protein surface is searched for continuous volume envelopes that correspond to a favorable protein–probe interaction. These volumes are subsequently analyzed to demarcate regions of high cumulative propensity for binding a carbohydrate moiety based on calculated amino acid propensity scores.InCa-SiteFinder¹ was tested on an independent test set of 80 protein–ligand complexes. It efficiently identifies carbohydrate binding sites with high specificity and sensitivity. It was also tested on a second test set of 80 protein–ligand complexes containing 40 known carbohydrate binders (having 40 carbohydrate binding sites) and 40 known drug-like compound binders (having 58 known drug-like compound binding sites) for the prediction of the location of the carbohydrate binding sites and to distinguish these from the drug-like compound binding sites. At 73% sensitivity the method showed 98% specificity. Almost all of the carbohydrate and drug-like compound binding sites were correctly identified with an overall error rate of 12%.     

Adaptation of group algebras to signal and image processing

Filtering techniques in digital signal and image processing typically use linear and/or cyclic convolutions, both of which are based on polynomial arithmetic. When the input data and the filter weights are treated as coefficients of polynomials, linear convolution is computed directly as a product of these polynomials. Cyclic convolution is used as an efficient means of computing the linear convolution. In this case, the input is organized into sections, each section treated as the coefficients of a polynomial. The output data are generated by selecting the last coefficients of the products of the section polynomials with the filter polynomial. We develop a more general methodology for filtering signals and images on the basis of the ideas of: (1) group algebras, a generalization of polynomials and polynomial arithmetic, and (2) value functions, a generalization of the coefficient selection used in generating the output data. Applications of these ideas to signal and image processing are given. Finally, the concepts are incorporated into the framework of image algebras.     

circ2CBA: prediction of circRNA-RBP binding sites combining deep learning and attention mechanism

Circular RNAs (circRNAs) are RNAs with closed circular structure involved in many biological processes by key interactions with RNA binding proteins (RBPs). Existing methods for predicting these interactions have limitations in feature learning. In view of this, we propose a method named circ2CBA, which uses only sequence information of circRNAs to predict circRNA-RBP binding sites. We have constructed a data set which includes eight sub-datasets. First, circ2CBA encodes circRNA sequences using the one-hot method. Next, a two-layer convolutional neural network (CNN) is used to initially extract the features. After CNN, circ2CBA uses a layer of bidirectional long and short-term memory network (BiLSTM) and the self-attention mechanism to learn the features. The AUC value of circ2CBA reaches 0.8987. Comparison of circ2CBA with other three methods on our data set and an ablation experiment confirm that circ2CBA is an effective method to predict the binding sites between circRNAs and RBPs.     

Identification of novel allosteric modulator binding sites in NMDA receptors: A molecular modeling study

The dysfunction of N-methyl-d-Aspartate receptors (NMDARs), a subtype of glutamate receptors, is correlated with schizophrenia, stroke, and many other neuropathological disorders. However, not all NMDAR subtypes equally contribute towards these disorders. Since NMDARs composed of different GluN2 subunits (GluN2A-D) confer varied physiological properties and have different distributions in the brain, pharmacological agents that target NMDARs with specific GluN2 subunits have significant potential for therapeutic applications. In our previous research, we have identified a family of novel allosteric modulators that differentially potentiate and/or inhibit NMDARs of differing GluN2 subunit composition. To further elucidate their molecular mechanisms, in the present study, we have identified four potential binding sites for novel allosteric modulators by performing molecular modeling, docking, and in silico mutations. The molecular determinants of the modulator binding sites (MBS), analysis of particular MBS electrostatics, and the specific loss or gain of binding after mutations have revealed modulators that have strong potential affinities for specific MBS on given subunits and the role of key amino acids in either promoting or obstructing modulator binding. These findings will help design higher affinity GluN2 subunit-selective pharmaceuticals, which are currently unavailable to treat psychiatric and neurological disorders.     

Investigation of structural requirements of anticancer activity at the paclitaxel/tubulin binding site using CoMFA and CoMSIA

CoMFA and CoMSIA analysis were utilized in this investigation to define the important interacting regions in paclitaxel/tubulin binding site and to develop selective paclitaxel-like active compounds. The starting geometry of paclitaxel analogs was taken from the crystal structure of docetaxel. A total of 28 derivatives of paclitaxel were divided into two groups-a training set comprising of 19 compounds and a test set comprising of nine compounds. They were constructed and geometrically optimized using SYBYL v6.6. CoMFA studies provided a good predictability (q(2)=0.699, r(2)=0.991, PC=6, S.E.E.=0.343 and F=185.910). They showed the steric and electrostatic properties as the major interacting forces whilst the lipophilic property contribution was a minor factor for recognition forces of the binding site. These results were in agreement with the experimental data of the binding activities of these compounds. Five fields in CoMSIA analysis (steric, electrostatic, hydrophobic, hydrogen-bond acceptor and donor properties) were considered contributors in the ligand-receptor interactions. The results obtained from the CoMSIA studies were: q(2)=0.535, r(2)=0.983, PC=5, S.E.E.=0.452 and F=127.884. The data obtained from both CoMFA and CoMSIA studies were interpreted with respect to the paclitaxel/tubulin binding site. This intuitively suggested where the most significant anchoring points for binding affinity are located. This information could be used for the development of new compounds having paclitaxel-like activity with new chemical entities to overcome the existing pharmaceutical barriers and the economical problem associated with the synthesis of the paclitaxel analogs. These will boost the wide use of this useful class of compounds, i.e. in brain tumors as the most of the present active compounds have poor blood-brain barrier crossing ratios and also, various tubulin isotypes has shown resistance to taxanes and other antimitotic agents.     

Influence of intermediate hydrogel layer and amount of binding sites on the signal response of surface acoustic wave biosensors

Surface acoustic wave (SAW) devices based on horizontally polarized surface shear waves allow direct and label-free detection of biomolecules in real time. Binding reactions on SAW sensor surfaces are detected by determining changes in surface wave velocity caused mainly by mass loading or viscoelasticity changes in the sensing layer. In many cases, analyte-specific capture molecules or ligands are covalently bound on the sensor surface via an intermediate hydrogel layer. It is a fact that the SAW signal response strongly depends on the nature of the hydrogel matrix due to different relative changes of its acousto-mechanical parameters such as density and viscoelasticity. We studied the effect of different hydrogels in two affinity assays. One assay used a low amount of immobilized capture molecules, the other a high amount of immobilized ligands as binding sites in the sensing layer. Significant variations of the SAW signal response were observed. However, performing the assay with immobilized capture molecules resulted in decreasing signal height with increasing molar mass of the hydrogel whereas a reverse signal behavior was obtained performing the assay with immobilized ligands. This means that each affinity system requires its specific hydrogel matrix to obtain maximal signal response.     

Aspects of dynamic programming in signal and image processing

The techniques peculiar to dynamic programming have found a variety of successful applications in the theory and practice of modern control. Successes in the theory and practice of signal and image processing are less numerous and prominent, but they do exist. In this paper, we sound a call for renewed attention to the potential of dynamic programming for solving knotty, nonlinear filtering problems in signal and image processing, and outline successes we have recently enjoyed in nonlinear frequency tracking and random boundary estimation in noisy black and white images. Two classical results, the fast Fourier transform and Levinson's recursion for determining autoregressive parameters, are treated in the context of dynamic programming simply to reinforce the point that many of the algorithms we take for granted, and which were derived without recourse to dynamic programming, can be nicely interpreted as dynamic programming algorithms.