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Recorded recurrent deep reinforcement learning guidance laws for intercepting endoatmospheric maneuvering missiles

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Defence technology（防务技术） 2024年第1期31卷 457-470页

作者： Xiaoqi Qiu Peng Lai Changsheng Gao Wuxing Jing Department of Aerospace Engineering Harbin Institute of TechnologyHarbin150001China shanghai Electro-Mechanical Engineering institute Shanghai Academy of Spaceflight TechnologyShanghai201100China

This work proposes a recorded recurrent twin delayed deep deterministic(RRTD3)policy gradient algorithm to solve the challenge of constructing guidance laws for intercepting endoatmospheric maneuvering missiles with uncertainties and observation *** attack-defense engagement scenario is modeled as a partially observable Markov decision process(POMDP).Given the benefits of recurrent neural networks(RNNs)in processing sequence information,an RNN layer is incorporated into the agent’s policy network to alleviate the bottleneck of traditional deep reinforcement learning methods while dealing with *** measurements from the interceptor’s seeker during each guidance cycle are combined into one sequence as the input to the policy network since the detection frequency of an interceptor is usually higher than its guidance *** training,the hidden states of the RNN layer in the policy network are recorded to overcome the partially observable problem that this RNN layer causes inside the *** training curves show that the proposed RRTD3 successfully enhances data efficiency,training speed,and training *** test results confirm the advantages of the RRTD3-based guidance laws over some conventional guidance laws.

关键词： Endoatmospheric interception Missile guidance Reinforcement learning Markov decision process Recurrent neural networks

A Layered Energy-Efficient Multi-no.e Scheduling Mechanism for Large-Scale WSN

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Computers, Materials & Continua 2024年第4期79卷 1335-1351页

作者： Xue Zhao Shaojun Tao Hongying Tang Jiang Wang Baoqing Li Science and technology on Microsystem Laboratory Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai200050China

In recent years, target tracking has been considered one of the most important applications of wireless sensornetwork (WSN). Optimizing target tracking performance and prolonging network lifetime are two equally criticalobjectives in this scenario. The existing mechanisms still have weaknesses in balancing the two demands. Theproposed heuristic multi-no.e collaborative scheduling mechanism (HMNCS) comprises cluster head (CH)election, pre-selection, and task set selectionmechanisms, where the latter two kinds of selections forma two-layerselection mechanism. The CH election inno.atively introduces the movement trend of the target and establishesa scoring mechanism to determine the optimal CH, which can delay the CH rotation and thus reduce energyconsumption. The pre-selection mechanism adaptively filters out suitable no.es as the candidate task set to applyfor tracking tasks, which can reduce the application consumption and the overhead of the following task setselection. Finally, the task no.e selection is mathematically transformed into an optimization problem and thegenetic algorithm is adopted to form a final task set in the task set selection mechanism. Simulation results showthat HMNCS outperforms other compared mechanisms in the tracking accuracy and the network lifetime.

关键词： no.e scheduling pre-selection target tracking WSN

Determining beam transverse absolute position by triangulation of multi-electrode signal phase differences

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维普期刊数据库

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Nuclear Science and Techniques 2024年第8期35卷 38-47页

作者： Xing Yang Hong‑Shuang Wang Yi‑Mei Zhou Yong‑Bin Leng shanghai institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese academy of Sciences Beijing 100049China shanghai Advanced Research institute Chinese Academy of SciencesShanghai 201204China University of Science and technology of China Hefei 230026China

Accurate measurement of the transverse position of a beam is crucial in particle accelerators because it plays a key role in determining the beam *** methods for beam-position measurement rely on the detection of image currents induced on electrodes or narrow-band wake field induced by a beam passing through a cavity-type ***,these methods have *** indirect measurement of multiple parameters is computationally complex,requiring external calibration to determine the system parameters in ***,the utilization of the beam signal information is ***,this study proposes a no.el method for measuring the absolute electron beam transverse *** utilizing the geometric relationship between the center position of the measured electron beam and multiple detection electrodes and by analyzing the differences in the arrival times of the beam signals detected by these electrodes,the absolute transverse position of the electron beam crossing the electrode plane can be *** method features absolute position measurement,a position sensitivity coefficient independent of vacuum chamber apertures,and no.requirement for a symmetrical detector electrode *** feasibility of this method is validated through numerical simulations and beam experiments.

关键词： Electron beam bunch-by bunch diagno.tics Bunch position measurement Triangulation method Bunch phase Bunch-by-bunch Transverse position Pickup signal

Ultrahigh spatiotemporal resolution beam signal reconstruction with bunch phase compensation

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Nuclear Science and Techniques 2024年第5期35卷 99-108页

作者： You-Ming Deng Yong-Bin Leng Xing-Yi Xu Jian Chen Yi-Mei Zhou shanghai institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of the Chinese academy of Sciences Beijing 100049China shanghai Synchrotron Radiation Facility Chinese Academy of SciencesShanghai 201204China University of Science and technology of China Hefei 230026China shanghai Advanced Research institute Chinese Academy of SciencesShanghai 201204China

Various electromagnetic signals are excited by the beam in the acceleration and beam-diagno.tic elements of a particle *** is important to obtain time-domain waveforms of these signals with high temporal resolution for research,such as the study of beam–cavity interactions and bunch-by-bunch parameter ***,a signal reconstruction algorithm with ultrahigh spatiotemporal resolution and bunch phase compensation based on equivalent sampling is proposed in this *** with traditional equivalent sampling,the use of phase compensation and setting the bunch signal zero-crossing point as the time reference can construct a more accurate reconstructed *** basic principles of the method,simulation,and experimental comparison are also *** on the beam test platform of the shanghai Synchrotron Radiation Facility(SSRF)and the method of experimental verification,the factors that affect the reconstructed signal quality are analyzed and discussed,including the depth of the sampled data,quantization no.se of analog-to-digital converter,beam transverse oscillation,and longitudinal *** results of the beam experiments show that under the user operation conditions of the SSRF,a beam excitation signal with an amplitude uncertainty of 2%can be reconstructed.

关键词： Turn-by-turn bunch phase compensation technique Equivalent sampling Signal reconstruction algorithm Ultrahigh spatiotemporal resolution SSRF

Conceptual design of a 714-MHz RFQ for compact proton injectors and development of a new tuning algorithm on its aluminium prototype

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Nuclear Science and Techniques 2024年第1期35卷 45-58页

作者： Yi-Xing Lu Wen-Cheng Fang Yu-Sen Guo Zhen-Tang Zhao shanghai institute of Applied Physics Chinese academy of Sciences Shanghai 201800China University of Chinese academy of Sciences Beijing 101408China shanghai Advanced Research institute Chinese academy of Sciences Shanghai 201204China shanghai Key Laboratory of Cryogenics&Superconducting RF technology Shanghai 201800China shanghaiTech University Shanghai 201210China

Radio frequency quadrupoles(RFQs),which are crucial components of proton injectors,significantly affect the performance of proton accelerator *** RFQ with a high frequency of 714 MHz dedicated to compact proton injectors for medi-cal applications is designed in this *** RFQ is designed to accelerate proton beams from 50 keV to 4 MeV within a short length of 2 m and can be matched closely with the downstream drift tube linac to capture more particles through a preliminary *** develop an advanced RFQ,challenging techniques,including fabrication and tuning method,must be evaluated and verified using a *** aluminium prototype is derived from the conceptual design of the RFQ and then redesigned to confirm the radio frequency performance,fabrication procedure,and feasibility of the tuning ***,a new tuning algorithm based on the response matrix and least-squares method is developed,which yields favorable results based on the prototype,i.e.,the errors of the dipole and quadrupole components reduced to a low level after several tuning *** from the conceptual design and techniques obtained from the prototype,the formal mechanical design of the 2-m RFQ is ready for the next manufacturing step.

关键词： Compact proton injector RFQ IH-DTL High gradient Tuning

A Fusion Localization Method Based on Target Measurement Error Feature Complementarity and Its Application

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Journal of Beijing institute of technology 2024年第1期33卷 75-88页

作者： Xin Yang Hongming Liu Xiaoke Wang Wen Yu Jingqiu Liu Sipei Zhang shanghai Electro-Mechanical Engineering institute Shanghai Academy of Spaceflight TechnologyShanghai 201109China

In the multi-radar networking system,aiming at the problem of locating long-distance targets synergistically with difficulty and low accuracy,a dual-station joint positioning method based on the target measurement error feature complementarity is *** dual-station joint positioning,by constructing the target positioning error distribution model and using the complementarity of spatial measurement errors of the same long-distance target,the area with high probability of target existence can be ***,based on the target distance information,the midpoint of the intersection between the target positioning sphere and the positioning tangent plane can be solved to acquire the target's optimal positioning *** simulation demonstrates that this method greatly improves the positioning accuracy of target in azimuth *** with the traditional the dynamic weighted fusion(DWF)algorithm and the filter-based dynamic weighted fusion(FBDWF)algorithm,it no. only effectively eliminates the influence of systematic error in the azimuth direction,but also has low computational ***,for the application scenarios of multi-radar collaborative positioning and multi-sensor data compression filtering in centralized information fusion,it is recommended that using radar with higher ranging accuracy and the lengths of baseline between radars are 20–100 km.

关键词： dual-station positioning feature complementarity information fusion engineering applicability

Corrosion behavior of pure metals(Ni and Ti)and alloys(316H SS and GH3535)in liquid GaInSn

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Nuclear Science and Techniques 2024年第3期35卷 70-83页

作者： Jian-Hui Yu Hong-Xia Xu Xiang-Xi Ye Bin Leng Han-Xun Qiu Xing-Tai Zhou School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai 200093China shanghai institute of Applied Physics Chinese Academy of SciencesShanghai 201800China

In this study,the interactions between a Ga-based liquid metal,GaInSn,and several metal materials,including pure metals(Ni and Ti)and alloys(316H stainless steel(SS)and GH3535),at 650℃were *** aim was to evaluate the corrosion performance and select a suitable candidate material for use as a molten salt mano.eter diaphragm in thermal energy storage *** results indicated that the alloys(316H SS and GH3535)exhibited less corrosion than pure metals(Ni and Ti)in liquid ***-rich binary intermetallic compounds were found to form on the surfaces of all the tested metal materials exposed to liquid GaInSn,as a result of the decomposition of liquid GaInSn and its reaction with the constituent elements of the metal *** corrosion mechanism for all the tested materials exposed to liquid GaInSn was also investigated and proposed,which may aid in selecting the optimal candidate material when liquid GaInSn is used as the pressure-sensing medium.

关键词： Metal materials Liquid GaInSn Corrosion Intermetallic compounds Thermal energy storage systems

Robust free-space optical frequency transfer in time-varying link distances conditions

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Chinese Physics B 2024年第2期33卷 271-276页

作者：童周刘雷王家亮操前金志成应康韩申生韩正甫桂有珍 School of Physical Sciences University of Science and Technology of ChinaHefei 230000China Key Laboratory for Quantum Optics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of space Laser Communication and Detection technology Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Hangzhou institute for Advanced Study University of Chinese Academy of SciencesHangzhou 310024China

Future inter-satellite clock comparison on high orbit will require optical time and frequency transmission technology between moving ***,we demonstrate robust optical frequency transmission under the condition of variable link *** variable link is accomplished by the relative motion of a single telescope fixed on the experimental platform to a corner-cube reflector(CCR)installed on a sliding *** acousto–optic modulators with different frequencies are used to separate forward signal from backward *** active phase no.se suppression,when the CCR moves back and forth at a constant velocity of 20 cm/s and an acceleration of 20 cm/s^(2),we achieve the best frequency stability of 1.9×10^(-16) at 1 s and 7.9×10^(-19) at 1000 s *** work paves the way for future studying optical frequency transfer between ultra-high-orbit satellites.

关键词： free-space optical frequency transfer variable link distance

Demonstration of acousto-optical modulation based on a thin-film AlScN photonic platform

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Photonics Research 2024年第6期12卷 1138-1149页

作者： KEWEI BIAN ZHENYU LI YUSHUAI LIU SUMEI XU XINGYAN ZHAO YANG QIU YUAN DONG QIZE ZHONG TAO WU SHAONAN ZHENG TING HU School of Microelectronics Shanghai UniversityShanghai 201800China School of Information Science and technology ShanghaiTech UniversityShanghai 201210China shanghai institute of Microsystem and Information technology Chinese Academy of SciencesShanghai 200050China University of Chinese academy of Sciences Beijing 100049China

Acousto-optic(AO)modulation technology holds significant promise for applications in microwave and optical signal ***-film scandium-doped aluminum nitride(AlScN),with excellent piezoelectric properties and a wide transparency window,is a promising candidate for achieving on-chip AO modulation with a fabri-cation process compatible with complementary metal-oxide-semiconductor(CMOS)*** study presents,to the best of our kno.ledge,the first demonstration of AO modulators with surface acoustic wave generation and photonic waveguides mono.ithically integrated on a 400-nm-thick film of AlScN on an *** intramodal AO modulation is realized based on an AlScN straight waveguide,and the modulation efficiency is significantly enhanced by 12.3 dB through the extension of the AO interaction length and the utilization of bidirectional acoustic *** intermodal AO modulation and no.-reciprocity are further demonstrated based on a multi-mode spiral waveguide,achieving a high no.-reciprocal contrast(>10 dB)across an optical bandwidth of 0.48 *** research marks a significant stride forward,representing an advancement in the realization of microwave photonic filters,magnet-free isolators,and circulators based on the thin-film AlScN photonic platform.

关键词： waveguide film microwave