Real-time polarization medium-wave infrared(MIR)optical imaging systems enable the acquisition of infrared and polarization information for a target.At present,real-time polarization MIR devices face the following pro...Real-time polarization medium-wave infrared(MIR)optical imaging systems enable the acquisition of infrared and polarization information for a target.At present,real-time polarization MIR devices face the following problems:poor real-time performance,low transmission and high requirements for fabrication and integration.Herein,we aim to improve the performance of real-time polarization imaging systems in the MIR waveband and solve the above-mentioned defects.Therefore,we propose a MIR polarization imaging system to achieve real-time polarization-modulated imaging with high transmission as well as improved performance based on a pixel-wise metasurface micro-polarization array(PMMPA).The PMMPA element comprises several linear polarization(LP)filters with different polarization angles.The optimization results demonstrate that the transmittance of the center field of view for the LP filters is up to 77%at a wavelength of4.0μm and an extinction ratio of 88 d B.In addition,a near-diffraction-limited real-time MIR imaging optical system is designed with a field of view of 5°and an F-number of 2.The simulation results show that an MIR polarization imaging system with excellent real-time performance and high transmission is achieved by using the optimized PMMPA element.Therefore,the method is compatible with the available optical system design technologies and provides a way to realize real-time polarization imaging in MIR wavebands.展开更多
In order to prevent the attacker from breaking through the blockade of the interception,deploying multiple Unmanned Aerial Vehicle(UAV)swarms on the interception line is a new combat style.To solve the optimal deploym...In order to prevent the attacker from breaking through the blockade of the interception,deploying multiple Unmanned Aerial Vehicle(UAV)swarms on the interception line is a new combat style.To solve the optimal deployment of swarm positions in the cooperative interception,an optimal deployment optimization model is presented by minimizing the penetration zones'area and the analytical expression of the optimal deployment positions is deduced.Firstly,from the view of the attackers breaking through the interception line,the situations of vertical penetration and oblique penetration are analyzed respectively,and the mathematical models of penetration zones are obtained under the condition of a single UAV swarm and multiple UAV swarms.Secondly,based on the optimization goal of minimizing the penetration area,the optimal deployment optimization model for swarm positions is proposed,and the analytical solution of the optimal deployment is solved by using the convex programming theory.Finally,the proposed optimal deployment is compared with the uniform deployment and random deployment to verify the validity of the theoretical analysis.展开更多
We design and demonstrate a one-dimensional grating coupler with a low polarization-dependent loss(PDL)for large spatial light spots.Based on current fabrication conditions,we first utilize genetic algorithms to find ...We design and demonstrate a one-dimensional grating coupler with a low polarization-dependent loss(PDL)for large spatial light spots.Based on current fabrication conditions,we first utilize genetic algorithms to find the optimal grating structure including the distributions of duty and periods,making the effective refractive index of transverse electric mode the same as that of transverse magnetic mode.The designed grating coupler is fabricated on the common silicon-on-insulator platform and the PDL is measured to be within 0.41 d B covering the C-band.展开更多
With apparent size and weight advantages,on-chip spectrometer could be a good choice for the spectrum analysis application which has been widely used in numerous areas such as optical network performance monitoring,ma...With apparent size and weight advantages,on-chip spectrometer could be a good choice for the spectrum analysis application which has been widely used in numerous areas such as optical network performance monitoring,materials analysis and medical research.In order to realize the broadband and the high resolution simultaneously,we propose a new on-chip spectrometer structure,which is a two-stage structure.The coarse wavelength division is realized by the cascaded Mach-Zehnder interferometers,which is the first stage of the spectrometer.The output of the Mach-Zehnder interferometers are further dispersed by the second stage structure,which can be realized either by arrayed waveguide gratings or by digital Fourier transform spectrometer structure.We further implemented the thermo-optic modulation for the arrayed waveguide gratings to achieve a higher spectral resolution.The output channel wavelengths of the spectrometer are modulated by the embedded heater to obtain the first order derivative spectra of the input optical signal to obtain a 2nm resolution.With respect to the computer simulation and device characterization results,the 400nm spectral range and the nanoscale resolution have been demonstrated.展开更多
In order to study the optimization configuration problem of bistatic sonar system,the optimal configuration model of bistatic sonar system was established.The positioning accuracy of the dual-base sonar at different d...In order to study the optimization configuration problem of bistatic sonar system,the optimal configuration model of bistatic sonar system was established.The positioning accuracy of the dual-base sonar at different dual-base angles was obtained by calculating the Cramér-Rao lower bound(CRLB)accuracy based on the optimal configuration model.The effect of system time measurement error and angle measurement error on positioning accuracy was analyzed by simulation.The transmitting and receiving sonar are deployed on the same circle centered on the target in the simulation.The results showed that the positioning accuracy was the highest at the bistatic angle of 2π/3.This research had certain reference for the optimal configuration of bistatic/multistatic sonar system.展开更多
The H_(∞)control method is an effective approach for attenuating the effect of disturbances on practical systems, but it is difficult to obtain the H_(∞)controller due to the nonlinear Hamilton-Jacobi-Isaacs equatio...The H_(∞)control method is an effective approach for attenuating the effect of disturbances on practical systems, but it is difficult to obtain the H_(∞)controller due to the nonlinear Hamilton-Jacobi-Isaacs equation, even for linear systems. This study deals with the design of an H_(∞)controller for linear discrete-time systems. To solve the related game algebraic Riccati equation(GARE), a novel model-free minimax Q-learning method is developed, on the basis of an offline policy iteration algorithm, which is shown to be Newton’s method for solving the GARE. The proposed minimax Q-learning method, which employs off-policy reinforcement learning, learns the optimal control policies for the controller and the disturbance online, using only the state samples generated by the implemented behavior policies. Different from existing Q-learning methods, a novel gradient-based policy improvement scheme is proposed. We prove that the minimax Q-learning method converges to the saddle solution under initially admissible control policies and an appropriate positive learning rate, provided that certain persistence of excitation(PE)conditions are satisfied. In addition, the PE conditions can be easily met by choosing appropriate behavior policies containing certain excitation noises, without causing any excitation noise bias. In the simulation study, we apply the proposed minimax Q-learning method to design an H_(∞)load-frequency controller for an electrical power system generator that suffers from load disturbance, and the simulation results indicate that the obtained H_(∞)load-frequency controller has good disturbance rejection performance.展开更多
云操作系统(云 OS ) 被用于管理云资源以便他们能有效地并且高效地被使用。并且另外为用户和应用程序提供方便接口是云 OS 的责任。然而，因为方便抽象通常需要更多的计算资源，这二个目标经常正在冲突。因此，云 OS 有它为支持云应用...云操作系统(云 OS ) 被用于管理云资源以便他们能有效地并且高效地被使用。并且另外为用户和应用程序提供方便接口是云 OS 的责任。然而，因为方便抽象通常需要更多的计算资源，这二个目标经常正在冲突。因此，云 OS 有它为支持云应用程序的各种各样的类型安排的资源管理和任务的自己的特征。云 OS 的进化被这二个经常冲突的目标事实上驾驶并且发现权利在他们之间的折衷做进化的每个阶段发生。在这份报纸，我们从三个不同方面调查了云 OS 进化的方法：创新技术进化， OS 建筑学进化和云生态系统进化。我们表演那发现适当 API (应用程序编程接口) 为下一个是批评的云 OS 的阶段进化。方便接口需要到没有苛责，被提供效率 API 什么时候被选择。我们在场一驾驶 API 遮蔽 OS 实践，为开发更好的云 OS 并且帮助健康地造并且跑云生态系统显示出 API 的大能力。展开更多
基金Project supported by the National Key R&D Program of China(Grant No.SKLA02020001A05)。
文摘Real-time polarization medium-wave infrared(MIR)optical imaging systems enable the acquisition of infrared and polarization information for a target.At present,real-time polarization MIR devices face the following problems:poor real-time performance,low transmission and high requirements for fabrication and integration.Herein,we aim to improve the performance of real-time polarization imaging systems in the MIR waveband and solve the above-mentioned defects.Therefore,we propose a MIR polarization imaging system to achieve real-time polarization-modulated imaging with high transmission as well as improved performance based on a pixel-wise metasurface micro-polarization array(PMMPA).The PMMPA element comprises several linear polarization(LP)filters with different polarization angles.The optimization results demonstrate that the transmittance of the center field of view for the LP filters is up to 77%at a wavelength of4.0μm and an extinction ratio of 88 d B.In addition,a near-diffraction-limited real-time MIR imaging optical system is designed with a field of view of 5°and an F-number of 2.The simulation results show that an MIR polarization imaging system with excellent real-time performance and high transmission is achieved by using the optimized PMMPA element.Therefore,the method is compatible with the available optical system design technologies and provides a way to realize real-time polarization imaging in MIR wavebands.
文摘In order to prevent the attacker from breaking through the blockade of the interception,deploying multiple Unmanned Aerial Vehicle(UAV)swarms on the interception line is a new combat style.To solve the optimal deployment of swarm positions in the cooperative interception,an optimal deployment optimization model is presented by minimizing the penetration zones'area and the analytical expression of the optimal deployment positions is deduced.Firstly,from the view of the attackers breaking through the interception line,the situations of vertical penetration and oblique penetration are analyzed respectively,and the mathematical models of penetration zones are obtained under the condition of a single UAV swarm and multiple UAV swarms.Secondly,based on the optimization goal of minimizing the penetration area,the optimal deployment optimization model for swarm positions is proposed,and the analytical solution of the optimal deployment is solved by using the convex programming theory.Finally,the proposed optimal deployment is compared with the uniform deployment and random deployment to verify the validity of the theoretical analysis.
基金Project supported by the National High Technology Research and Development Program of China(Grant No.18-H863-04-ZD-006-007-01)。
文摘We design and demonstrate a one-dimensional grating coupler with a low polarization-dependent loss(PDL)for large spatial light spots.Based on current fabrication conditions,we first utilize genetic algorithms to find the optimal grating structure including the distributions of duty and periods,making the effective refractive index of transverse electric mode the same as that of transverse magnetic mode.The designed grating coupler is fabricated on the common silicon-on-insulator platform and the PDL is measured to be within 0.41 d B covering the C-band.
基金This work was supported by the Chinese national found,through the pre-research project‘Research on the silicon integrated on-chip spectrometer’.
文摘With apparent size and weight advantages,on-chip spectrometer could be a good choice for the spectrum analysis application which has been widely used in numerous areas such as optical network performance monitoring,materials analysis and medical research.In order to realize the broadband and the high resolution simultaneously,we propose a new on-chip spectrometer structure,which is a two-stage structure.The coarse wavelength division is realized by the cascaded Mach-Zehnder interferometers,which is the first stage of the spectrometer.The output of the Mach-Zehnder interferometers are further dispersed by the second stage structure,which can be realized either by arrayed waveguide gratings or by digital Fourier transform spectrometer structure.We further implemented the thermo-optic modulation for the arrayed waveguide gratings to achieve a higher spectral resolution.The output channel wavelengths of the spectrometer are modulated by the embedded heater to obtain the first order derivative spectra of the input optical signal to obtain a 2nm resolution.With respect to the computer simulation and device characterization results,the 400nm spectral range and the nanoscale resolution have been demonstrated.
基金supported by the National High Technology Research and Development Program of China(863 Program,18-H863-04-2T-003-019-01)。
文摘In order to study the optimization configuration problem of bistatic sonar system,the optimal configuration model of bistatic sonar system was established.The positioning accuracy of the dual-base sonar at different dual-base angles was obtained by calculating the Cramér-Rao lower bound(CRLB)accuracy based on the optimal configuration model.The effect of system time measurement error and angle measurement error on positioning accuracy was analyzed by simulation.The transmitting and receiving sonar are deployed on the same circle centered on the target in the simulation.The results showed that the positioning accuracy was the highest at the bistatic angle of 2π/3.This research had certain reference for the optimal configuration of bistatic/multistatic sonar system.
基金supported by the National Natural Science Foundation of China (No. U1613225)。
文摘The H_(∞)control method is an effective approach for attenuating the effect of disturbances on practical systems, but it is difficult to obtain the H_(∞)controller due to the nonlinear Hamilton-Jacobi-Isaacs equation, even for linear systems. This study deals with the design of an H_(∞)controller for linear discrete-time systems. To solve the related game algebraic Riccati equation(GARE), a novel model-free minimax Q-learning method is developed, on the basis of an offline policy iteration algorithm, which is shown to be Newton’s method for solving the GARE. The proposed minimax Q-learning method, which employs off-policy reinforcement learning, learns the optimal control policies for the controller and the disturbance online, using only the state samples generated by the implemented behavior policies. Different from existing Q-learning methods, a novel gradient-based policy improvement scheme is proposed. We prove that the minimax Q-learning method converges to the saddle solution under initially admissible control policies and an appropriate positive learning rate, provided that certain persistence of excitation(PE)conditions are satisfied. In addition, the PE conditions can be easily met by choosing appropriate behavior policies containing certain excitation noises, without causing any excitation noise bias. In the simulation study, we apply the proposed minimax Q-learning method to design an H_(∞)load-frequency controller for an electrical power system generator that suffers from load disturbance, and the simulation results indicate that the obtained H_(∞)load-frequency controller has good disturbance rejection performance.
文摘云操作系统(云 OS ) 被用于管理云资源以便他们能有效地并且高效地被使用。并且另外为用户和应用程序提供方便接口是云 OS 的责任。然而，因为方便抽象通常需要更多的计算资源，这二个目标经常正在冲突。因此，云 OS 有它为支持云应用程序的各种各样的类型安排的资源管理和任务的自己的特征。云 OS 的进化被这二个经常冲突的目标事实上驾驶并且发现权利在他们之间的折衷做进化的每个阶段发生。在这份报纸，我们从三个不同方面调查了云 OS 进化的方法：创新技术进化， OS 建筑学进化和云生态系统进化。我们表演那发现适当 API (应用程序编程接口) 为下一个是批评的云 OS 的阶段进化。方便接口需要到没有苛责，被提供效率 API 什么时候被选择。我们在场一驾驶 API 遮蔽 OS 实践，为开发更好的云 OS 并且帮助健康地造并且跑云生态系统显示出 API 的大能力。
