As a new-style stochastic algorithm, the electromagnetism-like mechanism（EM） method gains more and more attention from many researchers in recent years. A novel model based on EM（NMEM） for multiobjective optimizat...As a new-style stochastic algorithm, the electromagnetism-like mechanism（EM） method gains more and more attention from many researchers in recent years. A novel model based on EM（NMEM） for multiobjective optimization problems is proposed, which regards the charge of all particles as the constraints in the current population and the measure of the uniformity of non-dominated solutions as the objective function. The charge of the particle is evaluated based on the dominated concept, and its magnitude determines the direction of a force between two particles. Numerical studies are carried out on six complex test functions and the experimental results demonstrate that the proposed NMEM algorithm is a very robust method for solving the multiobjective optimization problems.展开更多
The electromagnetism-like(EM)algorithm is a meta-heuristic optimization algorithm,which uses a novel searching mechanism called attraction-repulsion between charged particles.It is worth pointing out that there are tw...The electromagnetism-like(EM)algorithm is a meta-heuristic optimization algorithm,which uses a novel searching mechanism called attraction-repulsion between charged particles.It is worth pointing out that there are two potential problems in the calculation of particle charge by the original EM algorithm.One of the problems is that the information utilization rate of the population is not high,and the other problem is the decline of population diversity when the population size is much greater than the dimension of the problem.In contrast,it is more fully to exploit the useful search information based on the proposed new quadratic formula for charge calculation in this paper.Furthermore,the population size was introduced as a new multiplier term to improve the population diversity.In the end,numerical experiments were used to verify the performance of the proposed method,including a comparison with the original EM algorithm and other well-known methods such as artificial bee colony(ABC),and particle swarm optimization(PSO).The results showed the effectiveness of the proposed algorithm.展开更多
The Trichel pulse stage is an unstable stage of negative corona discharge that can also involve electromagnetic(EM)radiation signals.In this paper,the discharge mechanism and radiation characteristics of the Trichel p...The Trichel pulse stage is an unstable stage of negative corona discharge that can also involve electromagnetic(EM)radiation signals.In this paper,the discharge mechanism and radiation characteristics of the Trichel pulse are studied in the needle-plate electrode configuration.The Trichel pulse currenl and its EM radiation signals are measured at different applied voltages.The results show that Trichel pulse discharge changes from the nindom pulse stage to the continuous pulse stage as the applied voltage increases.During these different stages,the normalized shape of the Trichel pulses remains unchanged,while the frequency of the EM radiation generated by the discharge remains unchanged.The discharge mechanism and EM radiation characteristics of the Trichel pulse are theoretically analyzed in the different stages.Both the positive ion sheath and the negative ion cloud play key roles in the formation of the Trichel pulse.The EM radiati on signal is generated by the rapidly changing Trichel pulse current,and the Trichel pulse current waveform determines the characteristics of the EM radiation signal.展开更多
文章将仿电磁学算法EM(electromagnetism-like mechanism)同SFLA算法的优点结合起来构造了一种新的智能算法EMMG(electromagnetism-like mechanism based on multi groups),它具有较好的全局搜索和局部搜索能力,以及较快的收敛速度,且...文章将仿电磁学算法EM(electromagnetism-like mechanism)同SFLA算法的优点结合起来构造了一种新的智能算法EMMG(electromagnetism-like mechanism based on multi groups),它具有较好的全局搜索和局部搜索能力,以及较快的收敛速度,且具有较高的容错性。通过算例分析和仿真验证了该算法在故障区间定位过程中的优化性能和优化效率优于EM和GA算法,对含有畸变的故障信息进行故障诊断,具有较好的故障区间定位效果。基于以上理论成果,结合沈阳和平区10kV配电网的网架结构,运用C#软件和Oracle 10g数据库开发工具开发了一款故障诊断软件,有效实现了配电网故障诊断可视化。展开更多
Realizing ultra-wideband absorption,desirable attenuation capability at high temperature and mechanical requirements for real-life applications remains a great challenge for microwave absorbing materials.Herein,we hav...Realizing ultra-wideband absorption,desirable attenuation capability at high temperature and mechanical requirements for real-life applications remains a great challenge for microwave absorbing materials.Herein,we have constructed a porous carbon fiber/polymethacrylimide(CP)structure for acquiring promising microwave absorption performance and withstanding both elevated temperature and high strength in a low density.Given the ability of porous structure to induce desirable impedance matching and multiple reflection,the absorption bandwidth of CP composite can reach ultra-wideband absorption of 14 GHz at room temperature and even cover the whole X-band at 473 K.Additionally,the presence of imide ring group in polymethacrylimide and hard bubble wall endows the composite with excellent heat and compressive behaviors.Besides,the lightweight of the CP composite with a density of only 110 mg cm^(−3) coupled with high compressive strength of 1.05 MPa even at 453 K also satisfies the requirements in engineering applica-tions.Compared with soft and compressible aerogel materials,we envision that the rigid porous foam absorbing material is particularly suitable for environmental extremes.展开更多
基金supported by the National Natural Science Foundation of China(60873099)the Fundamental Research Funds for the Central Universities(2011QNA29)
文摘As a new-style stochastic algorithm, the electromagnetism-like mechanism（EM） method gains more and more attention from many researchers in recent years. A novel model based on EM（NMEM） for multiobjective optimization problems is proposed, which regards the charge of all particles as the constraints in the current population and the measure of the uniformity of non-dominated solutions as the objective function. The charge of the particle is evaluated based on the dominated concept, and its magnitude determines the direction of a force between two particles. Numerical studies are carried out on six complex test functions and the experimental results demonstrate that the proposed NMEM algorithm is a very robust method for solving the multiobjective optimization problems.
基金National Natural Science Foundation of China(Nos.61602398 and U19A2083)Science and Technology Development of Hunan Province,China(No.2019GK4007)。
文摘The electromagnetism-like(EM)algorithm is a meta-heuristic optimization algorithm,which uses a novel searching mechanism called attraction-repulsion between charged particles.It is worth pointing out that there are two potential problems in the calculation of particle charge by the original EM algorithm.One of the problems is that the information utilization rate of the population is not high,and the other problem is the decline of population diversity when the population size is much greater than the dimension of the problem.In contrast,it is more fully to exploit the useful search information based on the proposed new quadratic formula for charge calculation in this paper.Furthermore,the population size was introduced as a new multiplier term to improve the population diversity.In the end,numerical experiments were used to verify the performance of the proposed method,including a comparison with the original EM algorithm and other well-known methods such as artificial bee colony(ABC),and particle swarm optimization(PSO).The results showed the effectiveness of the proposed algorithm.
基金supported by National Natural Science Foundation of China(No.U1630130)
文摘The Trichel pulse stage is an unstable stage of negative corona discharge that can also involve electromagnetic(EM)radiation signals.In this paper,the discharge mechanism and radiation characteristics of the Trichel pulse are studied in the needle-plate electrode configuration.The Trichel pulse currenl and its EM radiation signals are measured at different applied voltages.The results show that Trichel pulse discharge changes from the nindom pulse stage to the continuous pulse stage as the applied voltage increases.During these different stages,the normalized shape of the Trichel pulses remains unchanged,while the frequency of the EM radiation generated by the discharge remains unchanged.The discharge mechanism and EM radiation characteristics of the Trichel pulse are theoretically analyzed in the different stages.Both the positive ion sheath and the negative ion cloud play key roles in the formation of the Trichel pulse.The EM radiati on signal is generated by the rapidly changing Trichel pulse current,and the Trichel pulse current waveform determines the characteristics of the EM radiation signal.
文摘文章将仿电磁学算法EM(electromagnetism-like mechanism)同SFLA算法的优点结合起来构造了一种新的智能算法EMMG(electromagnetism-like mechanism based on multi groups),它具有较好的全局搜索和局部搜索能力,以及较快的收敛速度,且具有较高的容错性。通过算例分析和仿真验证了该算法在故障区间定位过程中的优化性能和优化效率优于EM和GA算法,对含有畸变的故障信息进行故障诊断,具有较好的故障区间定位效果。基于以上理论成果,结合沈阳和平区10kV配电网的网架结构,运用C#软件和Oracle 10g数据库开发工具开发了一款故障诊断软件,有效实现了配电网故障诊断可视化。
基金National Natural Science Foundation of China(No.61863024)Scientific Research Projects of Higher Institutions of Gansu Province(No.2018C-11)+1 种基金Natural Science Foundation of Gansu Province(No.18JR3RA107)Science and Technology Program of Gansu Province(No.18CX3ZA004)。
文摘针对MEMS陀螺仪测量精度低、随机噪声具有不确定性和非线性的问题,提出一种基于最大期望算法(Expectation maximum,EM)和极大后验估计(Maximum a posterion,MAP)的无迹卡尔曼滤波(Unscented Kalman filter,UKF)——EMMAP-UKF的陀螺噪声估计与滤波方法。根据极大后验估计原理,构造出一种次优无偏MAP噪声统计估计模型,并在此基础上引入最大期望算法将噪声估计问题转换为数学期望极大化问题,实现对观测噪声方差的动态调整,最终实现陀螺仪随机漂移误差的估计与滤波处理。最后通过Allan方差对陀螺噪声滤波方法的性能进行评估,通过半实物仿真验证了本方法的有效性。
基金supported by the National Natural Science Foundation of China(52172091 and 52172295)the Interdisciplinary Innovation Foundation for Graduates(Nanjing University of Aeronautics and Astronautics,No.KXKCXJJ202009).
文摘Realizing ultra-wideband absorption,desirable attenuation capability at high temperature and mechanical requirements for real-life applications remains a great challenge for microwave absorbing materials.Herein,we have constructed a porous carbon fiber/polymethacrylimide(CP)structure for acquiring promising microwave absorption performance and withstanding both elevated temperature and high strength in a low density.Given the ability of porous structure to induce desirable impedance matching and multiple reflection,the absorption bandwidth of CP composite can reach ultra-wideband absorption of 14 GHz at room temperature and even cover the whole X-band at 473 K.Additionally,the presence of imide ring group in polymethacrylimide and hard bubble wall endows the composite with excellent heat and compressive behaviors.Besides,the lightweight of the CP composite with a density of only 110 mg cm^(−3) coupled with high compressive strength of 1.05 MPa even at 453 K also satisfies the requirements in engineering applica-tions.Compared with soft and compressible aerogel materials,we envision that the rigid porous foam absorbing material is particularly suitable for environmental extremes.
