Vibration parameter measurement using the temporal digital hologram sequence and windowed Fourier transform

Real time digital recording and numerical reconstruction of a temporal digital hologram sequence have become feasible in recent years.They provide a new measurement method which enjoys the valuable advantages of being full-field,noncontact and high precision.In this paper,a combined method of temporal digital hologram sequence and windowed Fourier transform is proposed to measure the kinematic parameters of random vibration.A series of holograms are recorded by CCD camera and the original phase can be reconstructed by Fresnel reconstruction algorithm.The three-dimensional windowed Fourier transform is used to filter noise in phase and extract the instantaneous kinematic parameters of the specimen,such as the displacement,velocity and acceleration.An experiment is conducted on a chloroprene rubber latex membrane.Results demonstrate that the proposed method determines the vibration parameters precisely and enjoys many merits.

Analysis of quaternary digital chaotic sequence performance based on chaotic matrix

With good randomness and high sensitivity to initial values,chaotic sequences have been extensively used in secure communication.Real chaotic sequences are highly sensitive to initial values.It is an analog quantity in the domain of attraction,which is not conducive to the transmission of digital signals.In order to improve the stability,real chaotic sequences can be quantized into digital chaotic sequences.According to the relationship between the information rate and the symbol rate,the symbol rate of binary sequence is the same as the information rate.The information rate can be doubled by quantizing a real-valued sequence into a quaternary sequence.The chaotic sequence has weak periodicity.Moreover,the periodicity of binary digital chaotic sequences is much weaker than that of quaternary chaotic sequences.Compared with the multi-dimensional chaotic map,the one-dimensional chaotic map has small key space and low security.In this paper,a new real-valued chaotic sequence is generated based on the chaotic matrix method constructed by Logistic map and Kent map.Two quantization methods are used to digitize the real-valued chaotic sequence to obtain the quaternary digital chaotic sequence.Moreover,the randomness,the time series complexity and the correlation of the new quaternary chaotic sequence are compared and studied.The simulation results demonstrate that the quaternary digital chaotic sequence obtained by the chaotic matrix has good randomness and correlation.

Design of Digital Hybrid Chaotic Sequence Generator

The feasibility of the hybrid chaotic sequences as the spreading codes in code divided multiple access(CDMA) system is analyzed. The design and realization of the digital hybrid chaotic sequence generator by very high speed integrated circuit hardware description language(VHDL) are described. A valid hazard canceledl method is presented. Computer simulations show that the stable digital sequence waveforms can be produced. The correlations of the digital hybrid chaotic sequences are compared with those of m-sequences. The results show that the correlations of the digital hybrid chaotic sequences are almost as good as those of m-sequences. The works in this paper explored a road for the practical applications of chaos.

Digital Karyotyping with Whole Genomic Sequencing for Complex Congenital Disorder

Complex congenital disorders may be caused by multiple genetic alterations and/or environmental hazards. Diagnosis and management of these diseases are usually difficult. Robust next-generation sequencing （NGS） technologies provide unprecedented opportunities to maximize mutation detection and improve genetic counseling and clinical management. Targeted or whole exome sequencing （WES） mainly detects protein-coding DNA sequence aberrations and is the major DNA sequencing technology that is entering clinical practice （Liu et al., 2014）.