The Discrete Walsh Hadamard Transform(DWHT)has emerged as an efficient alternative to the Discrete Fourier Transform(DFT)for Orthogonal Frequency Division Multiplexing(OFDM)implementations,particularly in handling cha...The Discrete Walsh Hadamard Transform(DWHT)has emerged as an efficient alternative to the Discrete Fourier Transform(DFT)for Orthogonal Frequency Division Multiplexing(OFDM)implementations,particularly in handling channel impairments.In this article,we proposed an efficient Joint Low Complexity Regularized Zero Forcing-Wavelet Domain Equalizer(JLCRLZF-WDE)to replace the traditional Frequency Domain Equalizer(FDE)in DWHT-OFDM systems.Unlike FDE,which requires additional DFT and Inverse DFT(IDFT)computations,the proposed JLCRLZF-WDE directly operates in the Walsh domain,effectively mitigating the computational overhead.The derivation of the proposed JLCRLZF-WDE equations take the effect of the channel,Co-Carrier Frequency Offset(Co-CFO),as well as the noise into account.During the derivation of the system model equations,we assume a MultipleInput-Multiple-Output(MIMO)-OFDM communication system through a Rayleigh fading channel.The Bit Error Rate(BER)performance and computational complexity of the proposed and the conventional algorithms are compared,indicating the significance of the proposed algorithm.Simulation results confirm the superiority of the proposed equalizer,demonstrating a 23.68%±28.4%reduction in computational complexity compared to Minimum Mean Square Error(LMMSE)-FDE based on DFT,while maintaining comparable BER performance at various MIMO configuration.Furthermore,at a BER of 10^(-4),the JLCRLZF-WDE achieves performance parity with conventional Walsh domain LMMSE equalizers,whereas other equalizers require an additional Signal-to-Noise Ratio(SNR)of 3.06 d B to achieve the same performance.展开更多
A cued search algorithm with uncertain detection performance is proposed for phased array radars. Firstly, a target search model based on the information gain criterion is presented with known detection performance, a...A cued search algorithm with uncertain detection performance is proposed for phased array radars. Firstly, a target search model based on the information gain criterion is presented with known detection performance, and the statistical characteristic of the detection probability is calculated by using the fluctuant model of the target radar cross section （RCS）. Secondly, when the detection probability is completely unknown, its probability density function is modeled with a beta distribution, and its posterior probability distribution with the radar observation is derived based on the Bayesian theory. Finally simulation results show that the cued search algorithm with a known RCS fluctuant model can achieve the best performance, and the algorithm with the detection probability modeled as a beta distribution is better than that with a random selected detection probability because the model parameters can be updated by the radar observation to approach to the real value of the detection probability.展开更多
The key advantage of unmanned swarm operation is its autonomous cooperation. How to improve the proportion of cooperators is one of the key issues of autonomous collaboration in unmanned swarm operations. This work pr...The key advantage of unmanned swarm operation is its autonomous cooperation. How to improve the proportion of cooperators is one of the key issues of autonomous collaboration in unmanned swarm operations. This work proposes a strategy dominance mechanism of autonomous collaboration in unmanned swarm within the framework of public goods game. It starts with the requirement analysis of autonomous collaboration in unmanned swarm;and an aspiration-driven multiplayer evolutionary game model is established based on the requirement. Then the average abundance function and strategy dominance condition of the model are constructed by theoretical derivation. Furthermore, the evolutionary mechanism of parameter adjustment in swarm cooperation is revealed via simulation,and the influences of the multiplication factor r, aspiration levelα, threshold m and other parameters on the strategy dominance conditions were simulated for both linear and threshold public goods games(PGGs) to determine the strategy dominance characteristics;Finally, deliberate proposals are suggested to provide a meaningful exploration in the actual control of unmanned swarm cooperation.展开更多
A fiber-optic confocal microscope has been analyzed by Fourier optics.It is found that the detected light intensity has three parts,each of which is depennted on the coupled lens,the detective lens,and the part compri...A fiber-optic confocal microscope has been analyzed by Fourier optics.It is found that the detected light intensity has three parts,each of which is depennted on the coupled lens,the detective lens,and the part comprised of the fiber and the microprobe.The simulated results show that the less the value of the parameter A is,which is dependent on the fiber and microprobe,the higher the axial resolution of the system is. For the case,as A→∞, the axial resolution is zero,which is corresponding to the conventional microscope.as A≤1,the axial resolution changes slightly,and is close to the optimal value,which is corresponding to the perfect confocal microscope.when the reflective loss takes place at the end of fiber,the contrast of axial intensity will decrease.All that will help the design of endoscope with confocal microscope at cellular level.展开更多
Target echo detection in the presence of strong reverberation is investigated by means of singular value decomposition (SVD) method. Simulation results indicate that the method can efficiently separate the target echo...Target echo detection in the presence of strong reverberation is investigated by means of singular value decomposition (SVD) method. Simulation results indicate that the method can efficiently separate the target echo from the reverberation and can improve the detection of target echo.展开更多
There exists MUSIC (multiple signal classification) algorithm for direction of arrival (DOA) estimation. This paper is to present a different MUSIC algorithm for more accurate estimation of low altitude target. The po...There exists MUSIC (multiple signal classification) algorithm for direction of arrival (DOA) estimation. This paper is to present a different MUSIC algorithm for more accurate estimation of low altitude target. The possibility of better performance is analyzed using a void reference sensor (VRS) in MUSIC algorithm. The following two topics are discussed: 1) the time delay formula and VRS-MUSIC algorithm with VRS located on the minus of z-axes; 2) the DOA estimation results of VRS-MUSIC and MUSIC algorithms. The simulation results show VRS-MUSIC algorithm has three advantages compared with MUSIC: 1) When the signal to noise ratio (SNR) is more than-5 dB, the direction estimation error is 1/2 as much as that obtained by MUSIC; 2) The side lobe is more lower and the stability is better; 3) The size of array that the algorithm requires is smaller.展开更多
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(RS-2018-NR031063)in part by the Research Grant of Kwangwoon University in 2025.
文摘The Discrete Walsh Hadamard Transform(DWHT)has emerged as an efficient alternative to the Discrete Fourier Transform(DFT)for Orthogonal Frequency Division Multiplexing(OFDM)implementations,particularly in handling channel impairments.In this article,we proposed an efficient Joint Low Complexity Regularized Zero Forcing-Wavelet Domain Equalizer(JLCRLZF-WDE)to replace the traditional Frequency Domain Equalizer(FDE)in DWHT-OFDM systems.Unlike FDE,which requires additional DFT and Inverse DFT(IDFT)computations,the proposed JLCRLZF-WDE directly operates in the Walsh domain,effectively mitigating the computational overhead.The derivation of the proposed JLCRLZF-WDE equations take the effect of the channel,Co-Carrier Frequency Offset(Co-CFO),as well as the noise into account.During the derivation of the system model equations,we assume a MultipleInput-Multiple-Output(MIMO)-OFDM communication system through a Rayleigh fading channel.The Bit Error Rate(BER)performance and computational complexity of the proposed and the conventional algorithms are compared,indicating the significance of the proposed algorithm.Simulation results confirm the superiority of the proposed equalizer,demonstrating a 23.68%±28.4%reduction in computational complexity compared to Minimum Mean Square Error(LMMSE)-FDE based on DFT,while maintaining comparable BER performance at various MIMO configuration.Furthermore,at a BER of 10^(-4),the JLCRLZF-WDE achieves performance parity with conventional Walsh domain LMMSE equalizers,whereas other equalizers require an additional Signal-to-Noise Ratio(SNR)of 3.06 d B to achieve the same performance.
基金supported by the National Natural Science Foundation of China (61372165)the Postdoctoral Science Foundation of China (201150M15462012T50874)
文摘A cued search algorithm with uncertain detection performance is proposed for phased array radars. Firstly, a target search model based on the information gain criterion is presented with known detection performance, and the statistical characteristic of the detection probability is calculated by using the fluctuant model of the target radar cross section （RCS）. Secondly, when the detection probability is completely unknown, its probability density function is modeled with a beta distribution, and its posterior probability distribution with the radar observation is derived based on the Bayesian theory. Finally simulation results show that the cued search algorithm with a known RCS fluctuant model can achieve the best performance, and the algorithm with the detection probability modeled as a beta distribution is better than that with a random selected detection probability because the model parameters can be updated by the radar observation to approach to the real value of the detection probability.
基金supported by the National Natural Science Foundation of China(71901217)the National Key R&D Program of China(2018YFC0806900).
文摘The key advantage of unmanned swarm operation is its autonomous cooperation. How to improve the proportion of cooperators is one of the key issues of autonomous collaboration in unmanned swarm operations. This work proposes a strategy dominance mechanism of autonomous collaboration in unmanned swarm within the framework of public goods game. It starts with the requirement analysis of autonomous collaboration in unmanned swarm;and an aspiration-driven multiplayer evolutionary game model is established based on the requirement. Then the average abundance function and strategy dominance condition of the model are constructed by theoretical derivation. Furthermore, the evolutionary mechanism of parameter adjustment in swarm cooperation is revealed via simulation,and the influences of the multiplication factor r, aspiration levelα, threshold m and other parameters on the strategy dominance conditions were simulated for both linear and threshold public goods games(PGGs) to determine the strategy dominance characteristics;Finally, deliberate proposals are suggested to provide a meaningful exploration in the actual control of unmanned swarm cooperation.
文摘A fiber-optic confocal microscope has been analyzed by Fourier optics.It is found that the detected light intensity has three parts,each of which is depennted on the coupled lens,the detective lens,and the part comprised of the fiber and the microprobe.The simulated results show that the less the value of the parameter A is,which is dependent on the fiber and microprobe,the higher the axial resolution of the system is. For the case,as A→∞, the axial resolution is zero,which is corresponding to the conventional microscope.as A≤1,the axial resolution changes slightly,and is close to the optimal value,which is corresponding to the perfect confocal microscope.when the reflective loss takes place at the end of fiber,the contrast of axial intensity will decrease.All that will help the design of endoscope with confocal microscope at cellular level.
文摘Target echo detection in the presence of strong reverberation is investigated by means of singular value decomposition (SVD) method. Simulation results indicate that the method can efficiently separate the target echo from the reverberation and can improve the detection of target echo.
基金National Nature Science Foundation of China(60672136)
文摘There exists MUSIC (multiple signal classification) algorithm for direction of arrival (DOA) estimation. This paper is to present a different MUSIC algorithm for more accurate estimation of low altitude target. The possibility of better performance is analyzed using a void reference sensor (VRS) in MUSIC algorithm. The following two topics are discussed: 1) the time delay formula and VRS-MUSIC algorithm with VRS located on the minus of z-axes; 2) the DOA estimation results of VRS-MUSIC and MUSIC algorithms. The simulation results show VRS-MUSIC algorithm has three advantages compared with MUSIC: 1) When the signal to noise ratio (SNR) is more than-5 dB, the direction estimation error is 1/2 as much as that obtained by MUSIC; 2) The side lobe is more lower and the stability is better; 3) The size of array that the algorithm requires is smaller.
