LMS ADAPTIVE TIME DELAY ESTIMATION WITH TWO WINDOWS

An LMS adaptive time delay estimation method with two windows is presented. This method can reduce the superfluous calculation greatly when the time of correlation is long. It is suitable for the time delay estimation of white band-limited random signals. The feasibility and the performances of this method are also studied.     

ANALYSIS OF CLOSED DIELECTRIC WAVEGUIDES——MULTIMODE NETWORK APPPOACH

The dispersion characteristics of a class of closed dielectric waveguides are investigated by themethod which combines the building-block approach of multimode network theory with the rigorous modematching procedure.Several numerical examples for difrerent guiding structures have been given by the ap-proach.The same structures are also analyzed with the finite element method and the EDC method forcomparison.The calculations show that the present approach yields as highly accurate results as the finite ele-ment method while almost retaining the simplicity of the EDC method,and justify the utility of the presentmethod.     

DETECTION OF SHIP WAKES IN SAR IMAGE USING ROTATED WINDOWS RADON TRANSFORM

A novel method of rotated window Radon transform is developed for identifying the linear texture in SAR image.It is applied to automatic detection of the ship wakes of SEASAT SAR image.The location and direction of the traveling ship can be quickly and accurately detectec,In some cases, the ship velocity can also be obtained.     

Wide——angle Beam Propagation Method Based on Oblique Coordinate

A wide-angle beam propagation algorithm based on an oblique coordinate system is presented. A waveguide with tilted structure is simulated in terms of this method and the conventional wide-angle BPM. By comparing the results, it is found that this method is effective especially in tilted structure. The Y-junction has been also simulated in terms of this new method,and the good results are obtained.     

TWO-DIMENSION ITERATIVE METHOD——A UNIFIED APPROACH FOR SOLVING LINEAR EQUATIONS

In this paper,a unified approach of iterative methods,such as Jacobi method,Gauss-Seidel method,and SOR method,for solving linear equations is discussed and studied.For the reason stated in this paper,this approach is called the two-dimension iterative method.The convergence range and the rate ofconvergence of iteration process are improved by using this new approach.The theoretical analysis and thecomputing results demonstrate that this approach has many advantages over the generally used iterativemethods.It is useful in solving large scale electric circuits,such as VLSI.     

SUPPRESSING THE COHERENT SPECKLE OF SAR IMAGES WITH WAVELET ANALYSIS

This paper studies Synthetic Aperture Radar (SAR) images contaminated by the coherent speckle noise with the multiresolution analysis of wavelet transform. This study shows that the influences of the speckle on different frequency components of the SAR image are different, and that the SAR image and the speckle have different manners of singularity. So, this paper presents a denoising method of wavelet analysis to reduce the speckle. Some experiments approve that this method not only suppresses the speckle effectively, but also preserves as much target characteristics of the original image as possible. It shows that this denoising method of wavelet analysis offers a very attractive alternative to suppress the coherent speckle noise of the SAR image.     

Influence of ring-down cavity parameters on intensity transmission property in trace gas concentration measurement

In this paper, we describe the basic principles and system design of continuous wave cavity ring-down spectroscopy (CW-CRDS). We also particularly study the nature and the behavior of a novel method to detune a laser and apply it to a cavity ring-down spectroscopy experiment. Both simulations and experiments are completed on the relation between the transmission characteristic and different reflectivities, as well as scanning speed. Output electric field equation is deduced. It has been investigated that how photons are coupled to the cavity and how to accumulate the intensity and leak out of the cavity as a function of time. It is noted that both accumulation of intensity and decay times decrease, and the oscillation amplitude increases as the reflectivity increases. Relative intensity increases with decreasing scanning velocity. Additionally, the simulations show that a non-detuned cavity displays the transmitted signals which are highly dependent on the mirror reflectivity and piezoelectric translator (PZT) modulation speed. Simulations also display that the laser switching off is different from detuning.     

2—D Fourier Transform Method for Optical Measurement of 3—D Surface

A emthod of 2-D Fourier transform used in 3-D surface profilometry is proposed,analyzed and compared with 1-D Fourier transform method in theory and practical measuring result.It was proved that the 2-D Fourier transform method has more advantages over 1-D Fourier transform methodd in biggest crook-rate limits,accuracy and sensitivity of measuring.Styudy on measuring object surface details with large crook-rate changing accurately used new higher-power index low-pass filter of spatial frequency domain.A new method of automatic produced reference grating image and error-correcting is proposed.One undeform row of deform grating image is used to extend a complete reference grating image,and some error-correcting method is used to process the result to get accurate surface shape and the deflection of reference surface normal line deviated from the axle of camera.By this new method,one deform rectangle grating image is only used to get the 3-D shape accurately.     

Making a Higher Hit Ratio Cryptanalytic Time-Memory Trade-Off Attack on Passwords

Most of implementations of the cryptana- lyric time-memory trade-off attacks such as Hellman＇s orig- inal method, Rivest＇s distinguished points cracking and Oechslin＇s rainbow attack are also considered as an ex- haustive attack to passwords in a limited length range on a certain charset. However＇s the distributions of structures and strings making up real human memorable passwords do not appear random. Based upon these, we propose a method to generate passwords in those cryptanalytic time- memory trade-off methods. It achieves a higher hit ra- tio in attacking actual passwords and reduces search space drastically with requirement of only a little extra memory. It makes time-memory trade-off more practical. Even to attack long length passwords, the results of experiments show that our approach has a higher hit ratio compared with Oechslin＇s method. In addition, this method can be used in the distributed and parallel attack.     

A new objective stereoscopic image assessment model based on stereoscopic perception

In order to establish a stereoscopic image quality assessment method which is consistent with human visual perception, we propose an objective stereoscopic image quality assessment method. It takes into account the strong correlation and high degree of structural between pixels of image. This method contains two models. One is the quality synthetic assessment of left-right view images, which is based on human visual characteristics, we use the Singular Value Decomposition （SVD） that can represent the degree of the distortion, and combine the qualities of left and right images by the characteristics of binocular superposition. The other model is stereoscopic perception quality as- sessment, due to strong stability of image＇s singular value characteristics, we calculate the distance of the singular values and structural characteristic similarity of the absolute difference maps, and utilize the statistical value of the global error to evaluate stereoscopic perception. Finally, we combine two models to describe the stereoscopic image quality. Experimental results show that the correlation coefficients of the proposed assessment method and the human subjective perception are above 0.93, and the mean square errors are all less than 6.2, under JPEG, JP2K compression, Gaussian blurring, Gaussian white noise, H.264 coding distortion, and hybrid cross distortion. It indicates that the proposed stereoscopic objective method is consistent with human visual properties and also of availability.     

Outage Performance of Cognitive AF Relay Networks with Imperfect CSI Based on Geometrical Analysis

This paper studies the outage performance of a cognitive Amplify-and-forward (AF) relay network subject to Rayleigh fading.Under the condition of imperfect Channel state information (CSI) estimations of the links from the secondary system to the Primary user (PU),the closed-form upper and lower bounds of the outage probability are derived through a geometrical analysis method.An asymptotic analysis of the outage probability is also derived in the high Signal-to-noise ratio (SNR) regime to gain additional insights on the system.The simulation results corroborate our theoretical analysis,and the effectiveness of the geometrical analysis method is verified with the conventional approach as a benchmark.The asymptotic results are very tight with the analytical lower bound in the high SNR regime.It also can be observed from the simulation results that the impact of the number of relays as well as the imperfect CSI on the outage probability and the diversity order.     

Integrated intrusion detection model based on artificial immune

The author puts forward an integrated intrusion detection （ID） model based on artificial immune （IIDAI）, a vaccination strategy based on the significance degree of genes and a method to generate initial memory antibodies with rough set （RS）. IIDAI integrates two kinds of intrusion detection mode： misuse detection and anonymous detection. Misuse detection and anonymous detection are applied to detect the known and the unknown attacks, respectively. On the basis of IIDAI model, an ID algorithm is presented. Simulation shows that the IIDAI has better performance than traditional ID methods in feasibility and effectiveness. It is very prone to achieve a higher convergence rate by using the vaccination strategy. Moreover, RS can remove the redundancy attributes and increase the detection speed. It can also increase detection rate by applying the integrated method.     

A Novel Method for Analyzing the Noise Characteristic of Solar Cells with En-In Model

In this paper, a novel method for analyzing the noise characteristic of solar cells with En-In model was studied. The En-In noise model in two-port network was introduced to study the low-frequency noise characteristic of solar cells. According to the relationship between the output noise power spectrum and the two noise parameters in En-In noise model of the solar cell, known as En and In, an accurate method for extracting the two noise parame- ters was proposed. At the same time, the measurement method for the both parameters from 1Hz to 10kHz was studied. After 1/f noise curve fitting and characteristic frequency of G-R noise extraction on the noise spectrums of a large amount of solar ceils, the analyzing results of spectrum compositions proved the validity and significance of the En-In noise model for noise analysis of solar cells. It also provided the essential theoretical and experimental basis for the further research on noise characteristic and reliability estimation of solar cells and PV modules.     

MEMS压阻式三轴加速度传感器的双路循环电桥检测法

A cycle bridge detection method, which uses a piezoresistive triaxial accelerometer, has been described innovatively. This method just uses eight resistors to form a cycle detection bridge, which can detect the signal of the three directions for real time. It breaks the law of the ordinary independent Wheatstone bridge detection method, which uses at least 12 resistors and each four resistors connected as a Wheatstone bridge to detect the output signal from a specific direction. In order to verify the feasibility of this method, the modeling and simulating of the sensor structure have been conducted by ANSYS, then the dual cycle bridge detection method and independent Wheatstone bridge detection method are compared, the result shows that the former method can improve the sensitivity of the sensor effectively. The sensitivity of the x, y-axis used in the former method is two times that of the sensor used in the latter method, and the sensitivity of the z-axis is four times. At the same time, it can also reduce the cross-axis coupling degree of the sensor used in the dual cycle bridge detection method. In addition, a signal amplifier circuit and adder circuit have been provided, Finally, the test result of the ＂eight-beams/mass＂ triaxial accelerometer, which is based on the dual cycle bridge detection method and the related circuits, have been provided. The results of the test and the theoretical analysis are consistent, on the whole.     

A PARAMETER ESTIMATION FOR DETECTION AND IMAGING OF MOVING TARGETS WITH SAR BY WVD

Based on a joint time-frequency two dimensional processing, this paper proposes a method for the detection and imaging of moving targets SAR by using Wigner-Ville Distribution (WVD). It is a parameter estimation method to generate a high resolution image. The problem of WVD in dealing with multi-point targets and extended targets are also discussed. The computer simulation results illustrate its availability.     

PRIMARY SUBGRAPH METHOD FOR LINEAR ACTIVE NETWORK ANALYSIS

This paper introduces the concept of the primary subgraph of a composite graph associated with alinear active network,and presents a new and efficient topological method,called the primary subgraphmethod,for linear active network analysis.This method is an improvement and unification of the completetree method and directed tree method.It thoroughly solves the sign evaluation problem and cancellationterm problem.     

Two—color Optical Fiber Pyrometer

On the basis of thermal radiation from solid surface to measeure tem-perature,a new two-color optical fiber pyrometer is put forward.It gets two thermal radiation signals by the method of Y-type optical fiber and narrow band filter for indi-cation of the temperature,Si diode in used for photoelectric measurement and MCS-51 single-chip microcomputer for sampling and handling.The system can output in digital and can print out instantaneous value,peak value and valley,It has many advan-tages such as quick measurement,small objective,high precision,high sensitivity and non-emissivity compensation.in addition,the special circuit of this pyrometer and the es-tablishment of mathematics model are discussed.     

Research of Malicious Code Attack Effect Based on Synthetic Entropy Method

To resolve the problem of assessing the effect of a network attack, this paper combines cross entropy with network character entropy method and proposes scheme to evaluate the malicious code attack effect. It captures the related indicators in real time and normalizes the data so as to evaluate it at the same level. It adopts cross entropy method to pretreat the indicators adaptively. We calculate the weight coefficient and exploit network character entropy method to evaluate the attack with accuracy according to the importance of the indicators in the evaluation system. Experimental results and corresponding comparisons reveal that the proposed method can quantitatively determine the exact effect of the malicious code attack.     

Non—touch Fiber—optic Reflective Displacement Sensor for Roller Wear

By accurately measuring the displacement between the roller surface and the optical fiber probe relative to a null position, we can test the roller wear. The whole testing method and system were introduced.Each part of the testing system was illustrated. And also a novel fiber—optic sensor with three probes in equal transverse space is adopted. Using this sensor, the effects of fluctuations in the light source, reflectivity changing of target surface and the intensity losses in the fiber lines are automatically compensated. This method offers such advantages as non—contact, no electromagnetic interference, simplicity, low cost, high sensitivity, good accuracy and stability.     

Transmission spectra of coated phase shifted long-period fiber gratings

The transmission spectrum of the coated phase-shifted long-pcriod fiber gratings （LPFCrs） with single and multiple phase shifts is analyzed by the coupled-mode theory and the transfer matrix method, and the influences of the film parameters on the spectral characteristics are also studied. It is shown that these parameters will affect the LPFG filtering characteristics. The loss peak of Wansmission spectrum decreases with the increase of film thickness, and the peak position shifts with the film refractive index. Compared with the non-coated phase-shifted LPFG, the coated one has the similar desirable filtering characteristics, and it has a flexible ability to adjust the transmission properties.