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1.
In this paper,we present a simulation method to reconstruct the object’s imaging in a ghost-imaging system.We use Laguerre-Gaussian(LG) beam as the light source which will produce the Orbital Angular Momentum(OAM) states.In the signal arm,the object spatial information is encoded as phase,and added to the phase of the signal light.In the idler arm,the phase of the idler light is changed according to the maximum coincidence rate in the receiver.We get each pixel matched phase of the object and reconstruct the object’s imaging in the idle arm.We demostrate some examples of the reconstruction and compare with the other reported method.The results show that our method can improve the resoltuion of the image effectively.  相似文献   

2.
In view of the fact that complex signals are often used in the digital processing of certain systems such as digital communication and radar systems,a new complex Duffing equation is proposed.In addition,the dynamical behaviors are analyzed.By calculating the maximal Lyapunov exponent and power spectrum,we prove that the proposed complex differential equation has a chaotic solution or a large-scale periodic one depending on different parameters.Based on the proposed equation,we present a complex chaotic oscillator detection system of the Duffing type.Such a dynamic system is sensitive to the initial conditions and highly immune to complex white Gaussian noise,so it can be used to detect a weak complex signal against a background of strong noise.Results of the Monte-Carlo simulation show that the proposed detection system can effectively detect complex single frequency signals and linear frequency modulation signals with a guaranteed low false alarm rate.  相似文献   

3.
A detection scheme for line spectrum of ship-radiated noise is proposed using Duffing oscillator. The chaotic trajectory of Duffing oscillator is analyzed and the state equation of the system is improved to detect weak periodic signals in different frequencies. According to the simulation results, the phase transforms of Duffing oscillator are sensitive to periodic signals and immune to the random noise and the periodic interference signals which have larger angular frequency difference from the referential signal. By employing Lyapunov exponents in the field of detection as the criteria for chaos, the phase transforms of dynamic behaviors in quantity are successfully determined. Meanwhile, the threshold value in critical state has been evaluated more accurately. Based on the phase transforms of Duffing oscillator, a new method for detecting line spectrum of ship-radiated noise is given. Three types of ship-radiated noise signals are analyzed and the values of line spectrum are acquired successfully by this method. The experimental results show that this method has high sensitivity and high resolution.  相似文献   

4.
The design and measured results of a broad-band direct quadrature phase shift keying(QPSK) modulator and demodulator are described in this paper.The circuits are fabricated using 1-m GaAs HBT technology.To suppress the local oscillator(LO) leakage,the double-balanced mixer is selected as the core unit in the modulator/demodulator.An embedded four-way quadrature divider which includes a Lange coupler and two Baluns is utilized in the system to generate quadrature-phase LO signals.As results of a back-to-back test,the system can operate at data rates in excess of 2 Gb/s(1 Gb/s per I and Q channels) at 30 GHz.The supplies of the modulator and demodulator are 5.0 V and 4.5 V with size of 1.35 mm×3.5 mm and 1.36 mm×3.4 mm,respectively.  相似文献   

5.
After periodic signals pass through some nonlinear systems, they are usually transformed into noise-like and wide-band chaotic signals. The discrete spectrums of the original periodic signals are often covered by the chaotic spectrums. Recovering the periodic driving signals from the chaotic signals is important not only in theory but also in practical applications. Based on the modeling theory of nonlinear dynamic system, a "polynomial-simple harmonic drive" non-autonomous equation (P-S equation) to approximate the original system is proposed and the approximation error between P-S equation and the original system is obtained. By changing the drive frequency, we obtain the curve of the approximation error vs. drive frequency. Based on the relation between this curve and the spectrums of the original periodic signals, the spectrum of the original driving signal is extracted and the original signal is recovered.  相似文献   

6.
A method of controllable internal perturbation inside the chaotic map is proposed to solve the problem in chaotic systems caused by finite precision.A chaotic system can produce large amounts of initial-sensitive,non-cyclical pseudo-random sequences.However,the finite precision brings short period and odd points which obstruct application of chaos theory seriously in digital communication systems.Perturbation in chaotic systems is a possible efficient method for solving finite precision problems,but former researches are limited in uniform distribution maps.The proposed internal perturbation can work on both uniform and non-uniform distribution chaotic maps like Chebyshev map and Logistic map.By simulations,results show that the proposed internal perturbation extends sequence periods and eliminates the odd points,so as to improve chaotic performances of perturbed chaotic sequences.  相似文献   

7.
8.
Chaos synchronization has been applied in secure communication, chemical reaction, biological systems, and information processing. A new theorem to synchronization of unified chaotic systems via adaptive control is proposed. The consutructive theorem provides the design scheme for adaptive controller such that a respond system can synchronize with respect to an uncertain drive system. One example for discontinuous chaotic system is proposed to illustrate the effectiveness and feasibility.  相似文献   

9.
It has been shown that much dynamic information is hidden in the pressure fluctuation signals of a gas-solid fluidized bed. Unfortunately, due to the random and capricious nature of this signal, it is hard to realize reliable analysis using traditional signal processing methods such as statistical analysis or spectral analysis, which is done in Fourier domain. Information in different frequency band can be extracted by using wavelet analysis. On the evidence of the composition of the pressure fluctuation signals, energy of low frequency (ELF) is proposed to show the transition of fluidized regimes from bubbling fluidization to turbulent fluidization. Plots are presented to describe the fluidized bed‘s evolution to help identify the state of different flow regimes and provide a characteristic curve to identify the fluidized status effectively and reliably.  相似文献   

10.
This paper presents a method for the generation of satisfied strange attractor images, which is based on the idea of Genetic Algorithm and is realized by adding a controller to a chaotic system.The principle of the method is introduced. Some problems which exist in genetic algorithm's parameter optimization are discussed in detail. Finally, the effectiveness of the method for finding pretty strange attractors is verified. It is helpful to pattern design and works of arts and crafts.  相似文献   

11.
Control uncertain continuous-time chaotic dynamical system   总被引:4,自引:0,他引:4  
The new chaos control method presented in this paper is useful for taking advantage of chaos.Based on sliding mode control theory, this paper provides a switching manifold controlling strategy of chaoticsystem, and also gives a kind of adaptive parameters estimated method to estimate the unknown systems‘ pa-rameters by which chaotic dynamical system can be synchronized. Taking the Lorenz system as example, and with the help of this controlling strategy, we can synchronize chaotic systems with unknown parameters and different initial conditions.  相似文献   

12.
In this paper, a novel method for signal decomposition and denoising is proposed based on a nonuniform filter bank (NUFB), which is derived from a uniform filter bank. With this method, the signal is firstly decomposed into M subbands using a uniform filter bank. Then according to their energy distribution, the corresponding consecutive filters are merged to compose the nonuniform filters. With the resulting NUFB, the signal can be readily matched and flexibly decomposed according to its power spectrum distribution. As another advantage, this method can be used to detect and remove the narrow-band noise from the corrupted signal. To verify the proposed method, a simulation of extracting the main information of an audio signal and removing its glitch is given.  相似文献   

13.
With the progress of DNA computing, DNA- based cryptography becomes an emerging interdisciplinary research field. In this paper, we present a novel DNA cryptography that takes advantage of DNA self assembled structure. Making use of the toehold strands recognition and strand displacement, the bit-wise exclusive-or (XOR) operation is carried out to fulfill the information encryption and decryption in the form of a one-time-pad. The security of this system mainly comes from the physical isolation and specificity of DNA molecules. The system is con- structed by using complex DNA self-assembly, in which technique of fluorescent detection is utilized to implement the signal processing. In the proposed DNA cryptography, the XOR operation at each bit is carried out individually, thus the encryption and decryption process could be con- ducted in a massive, parallel way. This work may dem- onstrate that DNA cryptography has the great potential applications in the field of inRwmation security.  相似文献   

14.
Decision Support Systems(DSS)are man-machine interaction systems,which support the de-cision-makers to solve the unstructured and semi-structured decisions,this paper advances that thefunction of problem-oriented information retrieval DSS can meet the needs of enterprise's topmanagement effectively in comparison with other information retrieval functions,in accordancewith the features of supporting information for decision.An architecture of this system is presented,which dissolves a problem put forward or recognized by the user into the problem recognized by thecomputer,forming retrieval tactics and searching the data the user needs.Designed and developedaccording to the architecture of this system,a prototype system is introduced,which is CF Econom-ic Environment Information Retrieval DSS.  相似文献   

15.
Adaptive interactive genetic algorithms with individual interval fitness   总被引:1,自引:0,他引:1  
It is necessary to enhance the performance of interactive genetic algorithms in order to apply them to complicated optimization problems successfully. An adaptive interactive genetic algorithm with individual interval fitness is proposed in this paper in which an indi-vidual fitness is expressed by an interval. Through analyzing the fitness, information reflecting the distribution of an evolutionary population is picked up, namely, the difference of evaluating superior individuals and the difference of evaluating a population. Based on these, the adaptive probabilities of crossover and mutation operators of an individual are presented. The algorithm proposed in this paper is applied to a fashion evolutionary design system, and the results show that it can find many satisfactory solutions per generation. The achievement of the paper provides a new approach to enhance the t~erformance of interactive genetic algorithms.  相似文献   

16.
The three types of connections (Permanent Connection, Soft Permanent Connection and Switched Connection) provided by ASON can adapt the requirement of different network services. Management and maintenance of these three connections are the most important aspect of ASON management. The information models proposed in this paper are used for the purpose of ASON connection management. Firstly a new information model is proposed to meet the requirement for the control plane introduced by ASON. In this model, a new class ControlNE is given, and the relationship between the ControlNE and the transport NE (network element) is also defined. Then this paper proposes information models for the three types of connections for the first time, and analyzes the relationship between the three kinds of connections and the basic network transport entities. Finally, the paper defines some CORBA interfaces for the management of the three connections. In these interfaces, some operations such as create or release a connection are defined, and some other operations can manage the performance of the three kinds of connections, which is necessary for a distributed management system.  相似文献   

17.
The global characteristics of a fingerprint image such as the ridge shape and ridge topology are often ignored in most automatic fingerprint verification system.In this paper,a new representative method based on B-Spline curve is proposed to address this problem.The resultant B-Spline curves can represent the global characteristics completely and the curves are analyzable and precise.An algorithm is also proposed to extract the curves from the fingerprint image.In addition to preserve the most information of the fingerprint image,the knot-points number of the B-Spline curve is reduced to minimum in this algorithm. At the same time,the influence of the fingerprint image noise is discussed.In the end,an example is given to demonstrate the effectiveness of the representation method.  相似文献   

18.
Fault diagnosis for helicopter’s main gearbox based on vibration signals by experiments always requires high costs. To solve this problem,a helicopter’s planetary gear system is taken as an example. Firstly,a simulation model is established by McFadden,and analyzed under ideal condition. Then this model is developed and improved as the delay-time model of the vibration signal which determines the phase-change of sidebands when the system is running. The cause and change-rules of planetary gear system’s vibration signal are analyzed to establish the fault diagnosis model.At the same time,the vibration signal of fault condition is simulated and analyzed. This simulation method can provide a reference for fault monitoring and diagnosis for planetary gear system.  相似文献   

19.
If the measuring signals wore input to the chaotic dynamic system as initial parameters, the system outputs might be in steady state, periodic state or chaos state. If the chaotic dynamic system outputs controlled in the periodic states, the periodic numbers would be changed most with the signals. Our novel method is to add chaotic dynamic vibration to the measurement or sensor system. The sensor sensitivity and precision of a measurement system would be improved with this method. Chaotic dynamics measurement algorithms are given and their sensitivity to parameters are analyzed in this paper. The effects of noises on the system are discussed,  相似文献   

20.
Henon CSK Secure Communication system Using Chaotic Turbo Codes   总被引:1,自引:0,他引:1  
In this paper,the authors design a novel chaotic secure communication system,which has high security and good error-correcting capability,Firstly,the Henon Chaos Shift Keying (CSK) modulation block is presented.Secondly,Chaotic turbo encoder/decoder(hard-decision)is introduced.Thirdly,this chaotic secure communication system,which comprises the Henon CSK modulation block and chaotic turbo encoder in a serially concatenated form,is shown.Furthermore,a novel two-step encryption scheme is proposed.which is based on the chaotic turbo encoded Henon CSK secure communication system.  相似文献   

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