We study the parameter estimation of a nonlinear chaotic system,which can be essentially formulated as a multidimensional optimization problem.In this paper,an orthogonal learning cuckoo search algorithm is used to es...We study the parameter estimation of a nonlinear chaotic system,which can be essentially formulated as a multidimensional optimization problem.In this paper,an orthogonal learning cuckoo search algorithm is used to estimate the parameters of chaotic systems.This algorithm can combine the stochastic exploration of the cuckoo search and the exploitation capability of the orthogonal learning strategy.Experiments are conducted on the Lorenz system and the Chen system.The proposed algorithm is used to estimate the parameters for these two systems.Simulation results and comparisons demonstrate that the proposed algorithm is better or at least comparable to the particle swarm optimization and the genetic algorithm when considering the quality of the solutions obtained.展开更多
An orthogonal wavelet transform fractionally spaced blind equalization algorithm based on the optimization of genetic algorithm(WTFSE-GA) is proposed in viewof the lowconvergence rate,large steady-state mean square er...An orthogonal wavelet transform fractionally spaced blind equalization algorithm based on the optimization of genetic algorithm(WTFSE-GA) is proposed in viewof the lowconvergence rate,large steady-state mean square error and local convergence of traditional constant modulus blind equalization algorithm(CMA).The proposed algorithm can reduce the signal autocorrelation through the orthogonal wavelet transform of input signal of fractionally spaced blind equalizer,and decrease the possibility of CMA local convergence by using the global random search characteristics of genetic algorithm to optimize the equalizer weight vector.The proposed algorithm has the faster convergence rate and smaller mean square error compared with FSE and WT-FSE.The efficiency of the proposed algorithm is proved by computer simulation of underwater acoustic channels.展开更多
Explicit structure-preserving geometric particle-in-cell(PIC)algorithm in curvilinear orthogonal coordinate systems is developed.The work reported represents a further development of the structure-preserving geometric...Explicit structure-preserving geometric particle-in-cell(PIC)algorithm in curvilinear orthogonal coordinate systems is developed.The work reported represents a further development of the structure-preserving geometric PIC algorithm achieving the goal of practical applications in magnetic fusion research.The algorithm is constructed by discretizing the field theory for the system of charged particles and electromagnetic field using Whitney forms,discrete exterior calculus,and explicit non-canonical symplectic integration.In addition to the truncated infinitely dimensional symplectic structure,the algorithm preserves exactly many important physical symmetries and conservation laws,such as local energy conservation,gauge symmetry and the corresponding local charge conservation.As a result,the algorithm possesses the long-term accuracy and fidelity required for first-principles-based simulations of the multiscale tokamak physics.The algorithm has been implemented in the Sym PIC code,which is designed for highefficiency massively-parallel PIC simulations in modern clusters.The code has been applied to carry out whole-device 6 D kinetic simulation studies of tokamak physics.A self-consistent kinetic steady state for fusion plasma in the tokamak geometry is numerically found with a predominately diagonal and anisotropic pressure tensor.The state also admits a steady-state subsonic ion flow in the range of 10 km s-1,agreeing with experimental observations and analytical calculations Kinetic ballooning instability in the self-consistent kinetic steady state is simulated.It is shown that high-n ballooning modes have larger growth rates than low-n global modes,and in the nonlinear phase the modes saturate approximately in 5 ion transit times at the 2%level by the E×B flow generated by the instability.These results are consistent with early and recent electromagnetic gyrokinetic simulations.展开更多
正交时频空(Orthogonal Time Frequency Space,OTFS)系统由于在面对高速移动通信场景下的时频双色散信道时的优异性能受到了广泛关注。为了准确获取信道状态信息,采用基于压缩感知的信道估计方法,并辅以特殊的导频序列完成信道估计。该...正交时频空(Orthogonal Time Frequency Space,OTFS)系统由于在面对高速移动通信场景下的时频双色散信道时的优异性能受到了广泛关注。为了准确获取信道状态信息,采用基于压缩感知的信道估计方法,并辅以特殊的导频序列完成信道估计。该文针对导频优化问题,提出了一种基于改进遗传算法的OTFS导频序列优化方法,该方法以互相关最小化为优化目标,采用遗传算法进行寻优,并能够自适应调整交叉和变异概率,在较少的迭代次数下即可实现比传统伪随机序列更优的互相关性,能够有效提高信道估计的准确性。此外,考虑到目标函数的计算量较大,该文分析了互相关的计算过程,并对其中的冗余计算进行了化简,与直接计算字典集的互相关值相比大大提高了算法的优化效率。展开更多
正交时频空(Orthogonal Time Frequency Space, OTFS)调制作为极具潜力的调制方案能够显著提升高移动场景下通信系统的鲁棒性。传统的OTFS同步消息传递(Message Passing, MP)检测算法及其变体每次迭代都需要更新并传递所有的信息,从而...正交时频空(Orthogonal Time Frequency Space, OTFS)调制作为极具潜力的调制方案能够显著提升高移动场景下通信系统的鲁棒性。传统的OTFS同步消息传递(Message Passing, MP)检测算法及其变体每次迭代都需要更新并传递所有的信息,从而导致收敛速度过慢。针对上述问题,提出基于残差的OTFS异步消息传递算法。该算法利用消息更新前后的差值作为知情调度信息来控制消息传递的顺序,从而实现迭代资源的非均匀分配。仿真结果表明,基于残差的OTFS异步消息传递算法相较于传统的同步消息传递算法,在信噪比为20 dB时,迭代次数减少了45%,误比特性能提高了7 dB。展开更多
a new strategy combining an expert system and improved genetic algorithms is presented for tuning proportional-integral-derivative （PID） parameters for petrochemical processes. This retains the advantages of genetic...a new strategy combining an expert system and improved genetic algorithms is presented for tuning proportional-integral-derivative （PID） parameters for petrochemical processes. This retains the advantages of genetic algorithms, namely rapid convergence and attainment of the global optimum. Utilization of an orthogonal experiment method solves the determination of the genetic factors. Combination with an expert system can make best use of the actual experience of the plant operators. Simulation results of typical process systems examples show a good control performance and robustness.展开更多
In order to minimize the transmitted power in the multi-user orthogonal frequency division multiplexing（OFDM） system, a scheme combining the improved particle swarm optimization（POS） algorithm with genetic algori...In order to minimize the transmitted power in the multi-user orthogonal frequency division multiplexing（OFDM） system, a scheme combining the improved particle swarm optimization（POS） algorithm with genetic algorithm（GA） is proposed to optimize the sub-carriers and bits allocation. In the algorithm, a random velocity between the maximum and minimum particle velocity is used as the updating velocity instead of maximum or minimum velocity when the updated particle velocity is higher than the maximum particle velocity or lower than the minimum particle velocity. Then, the convergence population is used as the initial population of the genetic algorithm to optimize the subcarriers and bits allocation further. Simulation results show that the transmitted power of the proposed algorithm is about 2 d B to 10 d B lower than that of the genetic algorithm, particle swarm optimization algorithm, and Zhang＇s algorithm.展开更多
To reconstruct the missing data of the total electron content （TEC） observations, a new method is proposed, which is based on the empirical orthogonal functions （EOF） decomposition and the value of eigenvalue itse...To reconstruct the missing data of the total electron content （TEC） observations, a new method is proposed, which is based on the empirical orthogonal functions （EOF） decomposition and the value of eigenvalue itself. It is a self-adaptive EOF decomposition without any prior information needed, and the error of reconstructed data can be estimated. The interval quartering algorithm and cross-validation algorithm are used to compute the optimal number of EOFs for reconstruction. The interval quartering algorithm can reduce the computation time. The application of the data interpolating empirical orthogonal functions （DINEOF） method to the real data have demonstrated that the method can reconstruct the TEC map with high accuracy, which can be employed on the real-time system in the future work.展开更多
The matrix inversion operation is needed in the MMSE decoding algorithm of orthogonal space-time block coding （OSTBC） proposed by Papadias and Foschini. In this paper, an minimum mean square error （MMSE） decoding ...The matrix inversion operation is needed in the MMSE decoding algorithm of orthogonal space-time block coding （OSTBC） proposed by Papadias and Foschini. In this paper, an minimum mean square error （MMSE） decoding algorithm without matrix inversion is proposed, by which the computational complexity can be reduced directly but the decoding performance is not affected.展开更多
非正交多址接入(Non-Orthogonal Multiple Access,NOMA)技术与设备到设备(Device-to-Device,D2D)通信技术相结合在实现高效频谱利用率和大规模接入上有着突出的优势。针对现有的NOMA-D2D系统存在的信道分配模式单一和D2D组内功率分配难...非正交多址接入(Non-Orthogonal Multiple Access,NOMA)技术与设备到设备(Device-to-Device,D2D)通信技术相结合在实现高效频谱利用率和大规模接入上有着突出的优势。针对现有的NOMA-D2D系统存在的信道分配模式单一和D2D组内功率分配难以获得最优解的问题,构建了以D2D组和速率为优化目标的联合资源分配算法的方案:首先,在子信道分配上,将问题转换为双边匹配问题,提出了一种基于多对一场景下的D2D组信道分配算法;然后运用基于逐次凸逼近的凸差分(Difference of two Convex functions,DC)编程方法求出接近最优的功率分配值。仿真结果表明,提出的多对一场景下信道匹配算法在和速率上明显优于一对一场景下的信道匹配算法,提出的功率分配算法相比起对偶迭代算法更接近最优功率分配。展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60473042,60573067 and 60803102)
文摘We study the parameter estimation of a nonlinear chaotic system,which can be essentially formulated as a multidimensional optimization problem.In this paper,an orthogonal learning cuckoo search algorithm is used to estimate the parameters of chaotic systems.This algorithm can combine the stochastic exploration of the cuckoo search and the exploitation capability of the orthogonal learning strategy.Experiments are conducted on the Lorenz system and the Chen system.The proposed algorithm is used to estimate the parameters for these two systems.Simulation results and comparisons demonstrate that the proposed algorithm is better or at least comparable to the particle swarm optimization and the genetic algorithm when considering the quality of the solutions obtained.
基金Sponsored by the Nature Science Foundation of Jiangsu(BK2009410)
文摘An orthogonal wavelet transform fractionally spaced blind equalization algorithm based on the optimization of genetic algorithm(WTFSE-GA) is proposed in viewof the lowconvergence rate,large steady-state mean square error and local convergence of traditional constant modulus blind equalization algorithm(CMA).The proposed algorithm can reduce the signal autocorrelation through the orthogonal wavelet transform of input signal of fractionally spaced blind equalizer,and decrease the possibility of CMA local convergence by using the global random search characteristics of genetic algorithm to optimize the equalizer weight vector.The proposed algorithm has the faster convergence rate and smaller mean square error compared with FSE and WT-FSE.The efficiency of the proposed algorithm is proved by computer simulation of underwater acoustic channels.
基金supported by the the National MCF Energy R&D Program(No.2018YFE0304100)National Key Research and Development Program(Nos.2016YFA0400600,2016YFA0400601 and 2016YFA0400602)+1 种基金National Natural Science Foundation of China(Nos.11905220 and 11805273)supported by the U.S.Department of Energy(DE-AC02-09CH11466)。
文摘Explicit structure-preserving geometric particle-in-cell(PIC)algorithm in curvilinear orthogonal coordinate systems is developed.The work reported represents a further development of the structure-preserving geometric PIC algorithm achieving the goal of practical applications in magnetic fusion research.The algorithm is constructed by discretizing the field theory for the system of charged particles and electromagnetic field using Whitney forms,discrete exterior calculus,and explicit non-canonical symplectic integration.In addition to the truncated infinitely dimensional symplectic structure,the algorithm preserves exactly many important physical symmetries and conservation laws,such as local energy conservation,gauge symmetry and the corresponding local charge conservation.As a result,the algorithm possesses the long-term accuracy and fidelity required for first-principles-based simulations of the multiscale tokamak physics.The algorithm has been implemented in the Sym PIC code,which is designed for highefficiency massively-parallel PIC simulations in modern clusters.The code has been applied to carry out whole-device 6 D kinetic simulation studies of tokamak physics.A self-consistent kinetic steady state for fusion plasma in the tokamak geometry is numerically found with a predominately diagonal and anisotropic pressure tensor.The state also admits a steady-state subsonic ion flow in the range of 10 km s-1,agreeing with experimental observations and analytical calculations Kinetic ballooning instability in the self-consistent kinetic steady state is simulated.It is shown that high-n ballooning modes have larger growth rates than low-n global modes,and in the nonlinear phase the modes saturate approximately in 5 ion transit times at the 2%level by the E×B flow generated by the instability.These results are consistent with early and recent electromagnetic gyrokinetic simulations.
文摘正交时频空(Orthogonal Time Frequency Space,OTFS)系统由于在面对高速移动通信场景下的时频双色散信道时的优异性能受到了广泛关注。为了准确获取信道状态信息,采用基于压缩感知的信道估计方法,并辅以特殊的导频序列完成信道估计。该文针对导频优化问题,提出了一种基于改进遗传算法的OTFS导频序列优化方法,该方法以互相关最小化为优化目标,采用遗传算法进行寻优,并能够自适应调整交叉和变异概率,在较少的迭代次数下即可实现比传统伪随机序列更优的互相关性,能够有效提高信道估计的准确性。此外,考虑到目标函数的计算量较大,该文分析了互相关的计算过程,并对其中的冗余计算进行了化简,与直接计算字典集的互相关值相比大大提高了算法的优化效率。
文摘正交时频空(Orthogonal Time Frequency Space, OTFS)调制作为极具潜力的调制方案能够显著提升高移动场景下通信系统的鲁棒性。传统的OTFS同步消息传递(Message Passing, MP)检测算法及其变体每次迭代都需要更新并传递所有的信息,从而导致收敛速度过慢。针对上述问题,提出基于残差的OTFS异步消息传递算法。该算法利用消息更新前后的差值作为知情调度信息来控制消息传递的顺序,从而实现迭代资源的非均匀分配。仿真结果表明,基于残差的OTFS异步消息传递算法相较于传统的同步消息传递算法,在信噪比为20 dB时,迭代次数减少了45%,误比特性能提高了7 dB。
文摘a new strategy combining an expert system and improved genetic algorithms is presented for tuning proportional-integral-derivative （PID） parameters for petrochemical processes. This retains the advantages of genetic algorithms, namely rapid convergence and attainment of the global optimum. Utilization of an orthogonal experiment method solves the determination of the genetic factors. Combination with an expert system can make best use of the actual experience of the plant operators. Simulation results of typical process systems examples show a good control performance and robustness.
基金supported by the National Natural Science Foundation of China under Grant No.61371112
文摘In order to minimize the transmitted power in the multi-user orthogonal frequency division multiplexing（OFDM） system, a scheme combining the improved particle swarm optimization（POS） algorithm with genetic algorithm（GA） is proposed to optimize the sub-carriers and bits allocation. In the algorithm, a random velocity between the maximum and minimum particle velocity is used as the updating velocity instead of maximum or minimum velocity when the updated particle velocity is higher than the maximum particle velocity or lower than the minimum particle velocity. Then, the convergence population is used as the initial population of the genetic algorithm to optimize the subcarriers and bits allocation further. Simulation results show that the transmitted power of the proposed algorithm is about 2 d B to 10 d B lower than that of the genetic algorithm, particle swarm optimization algorithm, and Zhang＇s algorithm.
基金supported by the National Natural Science Foundation of China(Grant No.41105013,41375028,and 61271106)the National Natural Science Foundation of Jiangsu Province,China(Grant No.BK2011122)the Key Laboratory of Meteorological Observation and Information Processing Scientific Research Fund of Jiangsu Province,China(Grant No.KDXS1205)
文摘To reconstruct the missing data of the total electron content （TEC） observations, a new method is proposed, which is based on the empirical orthogonal functions （EOF） decomposition and the value of eigenvalue itself. It is a self-adaptive EOF decomposition without any prior information needed, and the error of reconstructed data can be estimated. The interval quartering algorithm and cross-validation algorithm are used to compute the optimal number of EOFs for reconstruction. The interval quartering algorithm can reduce the computation time. The application of the data interpolating empirical orthogonal functions （DINEOF） method to the real data have demonstrated that the method can reconstruct the TEC map with high accuracy, which can be employed on the real-time system in the future work.
文摘The matrix inversion operation is needed in the MMSE decoding algorithm of orthogonal space-time block coding （OSTBC） proposed by Papadias and Foschini. In this paper, an minimum mean square error （MMSE） decoding algorithm without matrix inversion is proposed, by which the computational complexity can be reduced directly but the decoding performance is not affected.
文摘非正交多址接入(Non-Orthogonal Multiple Access,NOMA)技术与设备到设备(Device-to-Device,D2D)通信技术相结合在实现高效频谱利用率和大规模接入上有着突出的优势。针对现有的NOMA-D2D系统存在的信道分配模式单一和D2D组内功率分配难以获得最优解的问题,构建了以D2D组和速率为优化目标的联合资源分配算法的方案:首先,在子信道分配上,将问题转换为双边匹配问题,提出了一种基于多对一场景下的D2D组信道分配算法;然后运用基于逐次凸逼近的凸差分(Difference of two Convex functions,DC)编程方法求出接近最优的功率分配值。仿真结果表明,提出的多对一场景下信道匹配算法在和速率上明显优于一对一场景下的信道匹配算法,提出的功率分配算法相比起对偶迭代算法更接近最优功率分配。
