Autonomous air combat decision-making of UAV based on parallel self-play reinforcement learning

Aiming at addressing the problem of manoeuvring decision-making in UAV air combat,this study establishes a one-to-one air combat model,defines missile attack areas,and uses the non-deterministic policy Soft-Actor-Critic(SAC)algorithm in deep reinforcement learning to construct a decision model to realize the manoeuvring process.At the same time,the complexity of the proposed algorithm is calculated,and the stability of the closed-loop system of air combat decision-making controlled by neural network is analysed by the Lyapunov function.This study defines the UAV air combat process as a gaming process and proposes a Parallel Self-Play training SAC algorithm(PSP-SAC)to improve the generalisation performance of UAV control decisions.Simulation results have shown that the proposed algorithm can realize sample sharing and policy sharing in multiple combat environments and can significantly improve the generalisation ability of the model compared to independent training.

Encrypted optical fiber tag based on encoded fiber Bragg grating array

Optical fibers are typically used in telecommunications services for data transmission,where the use of fiber tags is essential to distinguish between the different transmission fibers or channels and thus ensure the working functionality of the communication system.Traditional physical entity marking methods for fiber labeling are bulky,easily confused,and,most importantly,the label information can be accessed easily by all potential users.This work proposes an encrypted optical fiber tag based on an encoded fiber Bragg grating(FBG)array that is fabricated using a point-by-point femtosecond laser pulse chain inscription method.Gratings with different resonant wavelengths and reflectivities are realized by adjusting the grating period and the refractive index modulations.It is demonstrated that a binary data sequence carried by a fiber tag can be inscribed into the fiber core in the form of an FBG array,and the tag data can be encrypted through appropriate design of the spatial distributions of the FBGs with various reflection wavelengths and reflectivities.The proposed fiber tag technology can be used for applications in port identification,encrypted data storage,and transmission in fiber networks.

Manoeuvre decision-making of unmanned aerial vehicles in air combat based on an expert actor-based soft actor critic algorithm

The demand for autonomous motion control of unmanned aerial vehicles in air combat is boosted as taking the initiative in combat appears more and more crucial.Unmanned aerial vehicles inability to manoeuvre autonomously during air combat that features highly dynamic and uncertain manoeuvres of the enemy;however,limits their combat capabilities,which proves to be very challenging.To meet the challenge,this article proposes an autonomous manoeuvre decision model using an expert actor-based soft actor critic algorithm that reconstructs empirical replay buffer with expert experience.Specifically,the algorithm uses a small amount of expert experience to increase the diversity of the samples,which can largely improve the exploration and utilisation efficiency of deep reinforcement learning.And to simulate the complex battlefield environment,a one-toone air combat model is established and the concept of missile's attack region is introduced.The model enables the one-to-one air combat to be simulated under different initial battlefield situations.Simulation results show that the expert actor-based soft actor critic algorithm can find the most favourable policy for unmanned aerial vehicles to defeat the opponent faster,and converge more quickly,compared with the soft actor critic algorithm.

Distributed Optimization Algorithm for Multi-Robot Formation with Virtual Reference Center

Dear editor,In this letter,we use a distributed optimization approach to solve a class of multi-robot formation problem with virtual reference center.We investigate the design and analysis of the constrained consensus algorithm to solve the optimization problem with a sum of objective functions with some local constraints.In the multi-robot system with virtual reference center,each robot has messages on its own constraints and objective function,as well as the message about the formation that interacts with the virtual reference center.At the same time,all the robots collaborate to find the minimum value of the function defined by the formation.To find the optimal formation,we propose an algorithm with fixed step size with better performance.In addition,we use a combination of the Hungarian assignment algorithm and the proposed formation algorithm to get the optimal matching formation of the multi-robot system.

基于零价铁的地下水化学还原修复体系中的电子转移有效性和电子竞争机制

近年来,基于零价铁的化学还原技术因其高效性逐渐被应用于受污染地下水的原位修复。但是,该技术在实际应用中仍面临一些亟待解决的问题。零价铁作为一种高活性的电子供体,除了和目标污染物反应外,还可以与地下水中其他的氧化性物质(如O_2、H^+或NO_3^-等)反应。这些反应所造成的零价铁腐蚀,不仅会降低修复效率还会增加地下水修复成本。此外,同类或多类污染物间也存在对零价铁所释放电子的相互竞争,从而影响各自的去除效率。本文综述了基于零价铁的地下水修复体系中的电子传递过程和氧化物间的电子竞争机制,从零价铁的腐蚀和电子传递、零价铁电子选择性量化指标的提出和量化方法、地下水体中多种共存氧化物间电子竞争作用、电子效率的影响因素以及强化措施等方面进行详细介绍。最后,对该技术今后发展方向作出了展望,以期为其今后实际的地下水修复应用提供参考。

Preparation and application of a phosphorous free and non- nitrogen scale inhibitor in industrial cooling water systems

A novel environmentally friendly type of calcium carbonate, zinc （Ⅱ） and iron （Ⅲ） scale inhibitor Acrylic acidallylpolyethoxy carboxylate copolymer （AA- APEL） was synthesized. The anti-scale property of the AA-APEL toward CaCO3, zinc （Ⅱ） and iron （Ⅲ） in the artificial cooling water was studied through static scale inhibition tests. The observation shows that both calcium carbonate, zinc （Ⅱ） and iron （Ⅲ） inhibition increase with increasing the dosage of AA-APEL. The effect on formation of CaCO3 was investigated with combination of scanning electronic microscopy （SEM）, transmission electron microscopy （TEM）, X-ray powder diffraction （XRD） analysis and fourier transform infrared spectrometer, respectively. The results showed that the AA-APEL copolymer not only influenced calcium carbonate crystal morphology and crystal size but also the crystallinity. The crystallization of CaCO3 in the absence of inhibitor was rhombohedral calcite crystal, whereas a mixture of calcite with vaterite crystals was found in the presence of the AA- APEL copolymer. Inhibition mechanism is proposed that the interactions between calcium or iron ions and polyethylene glycol （PEG） are the fundamental impetus to restrain the formation of the scale in cooling water systems.

Particulate matter 2.5 induced hyperpigmentation in reconstructed human epidermis model(MelaKutis®)

To the Editor:Epidemiological studies have confirmed that fine particulate matter(PM2.5)is related to skin hyperpigmentation,but experimental evidence is lacking.[1]Here,we used normal human epidermal keratinocytes(NHEKs),melanocytes(NHEMs),and reconstructed human epidermis models(MelaKutis®)to investigate the impact of PM2.5 on skin melanogenesis.MelaKutis®is a 3D skin model with a stratified structure,which is composed of human keratinocytes and melanocytes.Its structure and metabolic features are highly similar to those of the natural human skin.Moreover,external factors can stimulate the melanocytes located in the basal layer to produce melanin,resulting in hyperpigmentation.In our study,to simulate the effect of PM2.5 on human skin,we utilized PM2.5 collected in Beijing,China.Zhang et al[2]previously analyzed the components of PM2.5(collected in Beijing)and revealed that benzo[a]pyrene(BAP)was one of the most abundant and toxic components of PM2.5.Thus,we chose BAP as positive control.

Fine particulate matter 2.5 upregulates melanogenesis in A375 human melanoma cells

To the Editor:Epidemiological studies have shown that fine particulate matter 2.5(PM2.5)exposure increases the risk of skin hyperpigmentation.[1]recent'study proved that PM2.5 could induce melanogenesis by regulating tyrosinase(TYR),and tyrosinase-relatedproteini(TYRP1)and 2(TYRP2)expression via aryl hydrocarbon receptor(AhR)/mitogen-activated protein kinase signaling activation.