Adaptive Multi-Step Evaluation Design With Stability Guarantee for Discrete-Time Optimal Learning Control

This paper is concerned with a novel integrated multi-step heuristic dynamic programming(MsHDP)algorithm for solving optimal control problems.It is shown that,initialized by the zero cost function,MsHDP can converge to the optimal solution of the Hamilton-Jacobi-Bellman(HJB)equation.Then,the stability of the system is analyzed using control policies generated by MsHDP.Also,a general stability criterion is designed to determine the admissibility of the current control policy.That is,the criterion is applicable not only to traditional value iteration and policy iteration but also to MsHDP.Further,based on the convergence and the stability criterion,the integrated MsHDP algorithm using immature control policies is developed to accelerate learning efficiency greatly.Besides,actor-critic is utilized to implement the integrated MsHDP scheme,where neural networks are used to evaluate and improve the iterative policy as the parameter architecture.Finally,two simulation examples are given to demonstrate that the learning effectiveness of the integrated MsHDP scheme surpasses those of other fixed or integrated methods.

MBE:A Music Copyright Depository Framework Incorporating Blockchain and Edge Computing

Audio copyright is a crucial issue in the music industry,as it protects the rights and interests of creators and distributors.This paper studies the current situation of digital music copyright certification and proposes a music copyright certification framework based on“blockchain+edge computing mode,”abbreviated as MBE,by integrating edge computing into the Hyperledger Fabric system.MBE framework compresses and splits the audio into small chunks,performs Fast Fourier Transform(FFT)to extract the peak points of each frequency and combines them to obtain unique audio fingerprint information.After being confirmed by various nodes on the Fabric alliance chain,audio fingerprint information and copyright owner information are recorded on the chain and broadcast to all participants.Blockchain technology’s characteristics of being tamper-proof and traceable not only reform the trust mechanism of copyright protection but also endow edge computing with the ability to resist tampering and single-point attack,greatly enhancing the robustness of the music copyright certification system.Meanwhile,edge computing mode improves Fabric blockchain’s processing speed and transaction throughput.Experimental results show that MBE’s performance is better than traditional systems regarding efficiency,storage demand and security.Compared to the traditional Fabric system without edge computing mode,MBE exhibits a 53%higher deposition efficiency and a 48%lower storage space requirement.

Broadband high-efficiency polymerized liquid crystal metasurfaces with spin-multiplexed functionalities in the visible

Traditional optical components are usually designed for a single functionality and narrow operation band,leading to the limited practical applications.To date,it is still quite challenging to efficiently achieve multifunctional performances within broadband operating bandwidth via a single planar optical element.Here,a broadband high-efficiency polarization-multiplexing method based on a geometric phase polymerized liquid crystal metasurface is proposed to yield the polarization-switchable functionalities in the visible.As proofs of the concept,two broadband high-efficiency polymerized liquid crystal metalenses are designed to obtain the spin-controlled behavior from diffraction-limited focusing to sub-diffraction focusing or focusing vortex beams.The experimental results within a broadband range indicate the stable and excellent optical performance of the planar liquid crystal metalenses.In addition,low-cost polymerized liquid crystal metasurfaces possess unique superiority in large-scale patterning due to the straightforward processing technique rather than the point-by-point nanopatterning method with high cost and low throughput.The high-efficiency liquid crystal metasurfaces also have unrivalled advantages benefiting from the characteristic with low waveguide absorption.The proposed strategy paves the way toward multifunctional and high-integrity optical systems,showing great potential in mobile devices,optical imaging,robotics,chiral materials,and optical interconnections.

Intelligent reconfigurable metasurface for self-adaptively electromagnetic functionality switching

Reconfigurable metasurfaces have attracted a deal of attention owing to their multifunctional and dynamic electromagnetic(EM)manipulation properties.However,most of the previous reconfigurable metasurfaces rely on manual control for function switching,which has huge limitations in practical application.Here,an intelligent metasurface with the self-adaptively EM manipulation capability is proposed.It integrates the sensing-and-feedback components to construct a closed-loop system,which can automatically adjust EM functionalities for the different incident power information.The sensing module in this metasurface can first perceive the incident EM power intensity and then provide the feedback signal to the field programmable gate array controlling platform that can send the corresponding instruction to the executing material for switching the EM functionality among transmission,reflection,and tunable absorption.Good self-adaptive reaction capability and practicability of the proposed metasurface have been demonstrated by the experiment.It has the capability of making a real-time response with adaptive EM behavior to the varying incoming wave power without the aid of human beings.Our design provides an avenue toward intelligent and cognitive metasurfaces,which has extensive application prospects in smart skin,intelligent absorber,and the related EM fields.