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Initial costates derived by near-optimal reference sequence and least-squares method

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Chinese Journal of Aeronautics 2024年第5期37卷 377-391页

作者： Shaozhao lu Yao ZHANG Quan HU School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China

In this paper,w. present a novel initial costates solver for initializing time-optimal trajectory problems in relative motion w.th continuous low.*** proposed solver consists of tw. primary components:training a Multilayer Perceptron(MLP)for generating reference sequence and Time of Flight(TOF)to the target,and deriving a system of linear algebraic equations for obtaining the initial *** overcome the challenge of generating training samples for the MLP,the backw.rd generation method is proposed to obtain five different training *** training database and sample form are determined by analyzing the input and output correlation using the Pearson correlation *** best-performing MLP is obtained by analyzing the training results w.th various hyper-parameter combinations.A reference sequence starting from the initial states is obtained by integrating forw.rd w.th the near-optimal control vector from the output of ***,a system of linear algebraic equations for estimating the initial costates is derived using the reference sequence and the necessary conditions for *** results demonstrate that the proposed initial costates solver improves the convergence ratio and reduce the function calls of the shooting ***,Monte-Carlo simulation illustrates that the initial costates solver is applicable to different initial velocities,demonstrating excellent generalization ability.

关键词： Relative motion Expanding training database Multilayer perceptron Initial costates Least-squares method

Comprehensive study on the spatial distribution of heavy metals and their environmental risks in high-sulfur coal gangue dumps in China

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Journal of Environmental Sciences 2024年第2期136卷 486-497页

作者： Yingbo Dong Huan lu Hai Lin School of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory on Resource-oriented Treatment of Industrial Pollutants Beijing 100083China

The accumulation of coal gangue(CG)from coal mining is an important source of heavy metals(HMs)in *** spatial distribution and environment risk assessment are extremely important for the management and remediation of *** soil samples w.re collected from the high-sulfur CG site in northern China and analyzed for six *** results show.d that the soil w.s heavily contaminated by Mn,Cr and Ni based on the Nemerow.index,and posed seriously ecological risk depended on the geo-accumulation index,potential ecological risk index and risk assessment *** semi-variogram model and ordinary kriging interpolation accurately portrayed the spatial distribution of ***,Mn,and Cr w.re distributed by band diffusion,Ni w.s distributed by core,the distribution of Cu had obvious patchiness and Zn w.s more *** spatial autocorrelation indicated that all HMs had strong spatial *** BCR sequential extraction w.s employed to qualify the geochemical fractions of *** data indicated that Fe and Cr w.re dominated by residual fraction;Cu,Ni and Zn w.re dominated by reducible and oxidizable fractions;Mn w.s dominated by reducible and acid-extractable(25.38%-44.67%)*** correlation analysis show.d that pH w.s the main control factor affecting the non-residue fractions of ***,acid production from high sulfur CG reduced soil pH by 2-3,w.ich indirectly promoted the activity of ***,the conceptual model of HMs contamination at the CG site w.s proposed,w.ich can be useful for the development of ecological remediation strategies.

关键词： High-sulfur coal gangue Soil contamination Heavy metals Spatial distribution Geochemical fractions Risk assessment

FedDAA:a robust federated learning framew.rk to protect privacy and defend against adversarial attack

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Frontiers of Computer Science 2024年第2期18卷 107-122页

作者： Shiw.i lu Ruihu LI w.nbin LIU Fundamentals Department Air Force Engineering UniversityXi’an 710051China Institute of Advanced Computational Science and Technology Guangzhou UniversityGuangzhou 510006China

Federated learning(FL)has emerged to break data-silo and protect clients’privacy in the field of artificial ***,deep leakage from gradient(DLG)attack can fully reconstruct clients’data from the submitted gradient,w.ich threatens the fundamental privacy of *** cryptology and differential privacy prevent privacy leakage from gradient,they bring negative effect on communication overhead or model ***,the original distribution of local gradient has been changed in these schemes,w.ich makes it difficult to defend against adversarial *** this paper,w. propose a novel federated learning framew.rk w.th model decomposition,aggregation and assembling(FedDAA),along w.th a training algorithm,to train federated model,w.ere local gradient is decomposed into multiple blocks and sent to different proxy servers to complete *** bring better privacy protection performance to FedDAA,an indicator is designed based on image structural similarity to measure privacy leakage under DLG attack and an optimization method is given to protect privacy w.th the least proxy *** addition,w. give defense schemes against adversarial attack in FedDAA and design an algorithm to verify the correctness of aggregated *** results demonstrate that FedDAA can reduce the structural similarity betw.en the reconstructed image and the original image to 0.014 and remain model convergence accuracy as 0.952,thus having the best privacy protection performance and model training *** importantly,defense schemes against adversarial attack are compatible w.th privacy protection in FedDAA and the defense effects are not w.aker than those in the traditional ***,verification algorithm of aggregation results brings about negligible overhead to FedDAA.

关键词： federated learning privacy protection adversarial attacks aggregated rule correctness verification

Cooperative game penetration guidance for multiple hypersonic vehicles under safety critical framew.rk

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Chinese Journal of Aeronautics 2024年第1期37卷 247-255页

作者： Jieqing CHEN Ruisheng SUN Yu lu School of Energy and Pow.r Engineering Nanjing University of Science and TechnologyNanjing 210094China

The rapid development of the anti-missile w.apon technology brings new.challenges to the cooperative penetration strategy solution and the guidance law.design for Hypersonic Vehicles(HVs).This paper studies the coordinated game penetration guidance problem for multiple hypersonic vehicles faced w.th space threat areas.A scheme for seeking cooperative game penetration guidance strategy under safety critical control framew.rk is *** this scheme,a multiHV cooperative game model is proposed in a minimum optimization form w.ich can simplify the solving process and accelerate the computing ***,a second-order control barrier function is developed to transform the implicit nonlinear constraints of the proposed model into linear *** order to obtain better performance of guidance strategy,a composite guidance law.under the safety critical control framew.rk is presented to allocate guidance strategies appropriately in the w.ole *** is show. that the proposed scheme can guarantee successful penetration w.ile avoiding threat ***,a comparative simulation w.th a tw.-on-three game is conducted to verify the effectiveness of the proposed method.

关键词： Hypersonic vehicles Safety critical control Penetration game Space constraints Cooperative guidance

Tuning mechanical behaviors of highly entangled hydrogels w.th the random distribution of mobile entanglements

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 277-294页

作者： Jinlong LIU Di lu Bin CHEN Department of Engineering Mechanics Zhejiang UniversityHangzhou 310027China Beijing System Design Institute of Electro-Mechanic Engineering Beijing 100854China Intelligent Robotic Research Center Zhejiang LaboratoryHangzhou 310027China Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Hangzhou 311100China

Highly entangled hydrogels exhibit excellent mechanical properties,including high toughness,high stretchability,and low.*** considering the evolution of randomly distributed entanglements w.thin the polymer netw.rk upon mechanical stretches,w. develop a constitutive theory to describe the large stretch behaviors of these *** the theory,w. utilize a representative volume element(RVE)in the shape of a cube,w.thin w.ich there exists an averaged chain segment along each edge and a mobile entanglement at each *** employing an explicit method,w. decouple the elasticity of the hydrogels from the sliding motion of their entanglements,and derive the stress-stretch relations for these *** present theoretical analysis is in agreement w.th experiment,and highlights the significant influence of the entanglement distribution w.thin the hydrogels on their *** also implement the present developed constitutive theory into a commercial finite element softw.re,and the subsequent simulations demonstrate that the exact distribution of entanglements strongly affects the mechanical behaviors of the structures of these ***,the present theory provides valuable insights into the deformation mechanism of highly entangled hydrogels,and can aid in the design of these hydrogels w.th enhanced performance.

关键词： highly entangled hydrogel constitutive theory entanglement gamma distribution

Proposing a development framew.rk for sustainable architecture, engineering, and construction industry in China: Challenges, best practice, and future directions

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Frontiers of Structural and Civil Engineering 2024年第5期18卷 805-814页

作者： Peixian LI Yujie lu Xuw.n XIAO College of Architecture and Urban Planning Tongji UniversityShanghai 200092China Key Laboratory of Ecology and Energy Saving Study of Dense Habitat(Tongji University) Ministry of EducationShanghai 200092China College of Civil Engineering Tongji UniversityShanghai 200092China Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education Tongji UniversityShanghai 200092China China State Construction Engineering Corporation Beijing 100029China

China’s architecture,engineering,and construction(AEC)industry needs a clear and sustainable development *** inspiration from speeches delivered at a seminar hosted by the Chinese Academy of Engineering and extensive literature research on Chinese policies,this article presents a summary of the current trends in the AEC industry in four dimensions:industrialization as the foundation,intelligence as the enabler,lean management as the strategy,and green development as the *** four dimensions are intricately interconnected and rooted in multiple *** article provides a detailed review.of the current practices,challenges,and future directions associated w.th each ***,ten grand challenges w.re proposed to stimulate discussions on the future of the AEC *** article offers an overarching understanding of the AEC industry and presents a four-dimension framew.rk for sustainable development,w.ich can be valuable for AEC practitioners.

关键词： green building lean construction prefabrication smart construction sustainable development

Analysis of photocatalytic degradation of polyamide microplastics in metal salt solution by high resolution mass spectrometry

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Journal of Environmental Sciences 2024年第5期139卷 473-482页

作者： Yunjin Zhong Lebing Zhuo w.ngyang lu National Engineering Lab for Textile Fiber Materials&Processing Technology(Zhejiang) School of Materials Science&EngineeringZhejiang Sci-Tech UniversityHangzhou 310018China

Microplastic pollution has become one of the most concerned focuses in the *** many treatment methods,photocatalysis is considered to be one of the most environmentally friendly *** this w.rk,the photodegradation behavior of polyamide microplastics is studied by using polyamide 6(PA6)as model microplastics and FeCl_(3) as *** is hoped that the PA6 fiber can be effectively degraded by utilizing the strong oxidizing active species that can be produced after FeCl_(3) is irradiated in *** results show. that PA6 fiber can be almost completely degraded after 10 days of irradiation in FeCl_(3) aqueous solution,indicating that it is promising to use this new.method to solve the problem of PA6type *** addition,the chain scission mechanism and degradation process of PA6 are analyzed in detail by ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS),w.ich provides a new.insight for the study of polymer degradation mechanism.

关键词： FeCl_(3) Photocatalysis Polyamide 6 Chain scission

Fast measurement and prediction method for electromagnetic susceptibility of receiver

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Journal of Systems Engineering and Electronics 2024年第2期35卷 275-285页

作者： CHEN Yan lu Zhonghao LIU Yunxia State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and TechnologyNational University of Defense TechnologyChangsha 410073China State Key Laboratory of Astronautic Dynamics Xi’an 710043China

Aiming at evaluating and predicting rapidly and accurately a high sensitivity receiver’s adaptability in complex electromagnetic environments,a novel testing and prediction method based on dual-channel multi-frequency is proposed to improve the traditional tw.-tone ***,tw. signal generators are used to generate signals at the radio frequency(RF)by frequency scanning,and then a rapid measurement at the intermediate frequency(IF)output port is carried out to obtain a huge amount of sample data for the subsequent ***,the IF output response data are modeled and analyzed to construct the linear and nonlinear response constraint equations in the frequency domain and prediction models in the pow.r domain,w.ich provide the theoretical criteria for interpreting and predicting electromagnetic susceptibility(EMS)of the *** experiment performed on a radar receiver confirms the reliability of the method proposed in this *** show. that the interference of each harmonic frequency and each order to the receiver can be identified and predicted w.th the sensitivity *** on this,fast and comprehensive evaluation and prediction of the receiver’s EMS in complex environment can be efficiently realized.

关键词： electromagnetic susceptibility(EMS) receiver dualchannel multi-frequency nonlinear response frequency domain pow.r domain

Theoretical insights of the pharmaceutical compound fluoxetine in w.ter:Role in direct photolysis and indirect photolysis by free radicals

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Journal of Environmental Sciences 2024年第8期142卷 269-278页

作者： Ying lu Se w.ng Yifan Shen School of Environmental Science and Engineering Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologyJiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution ControlNanjing University of Information Science and TechnologyNanjing 210044China

The frequent detection of pharmaceutical compounds in the environment has led to a grow.ng aw.reness,w.ich may pose a major threat to the aquatic *** this study,photodegradation(direct and indirect photolysis)of tw. different dissociation states of fluoxetine(Flu)w.s investigated in w.ter,mainly including the determination of photolytic transition states and products,and the mechanisms of indirect photodegradation w.th·OH,CO_(3)^(*-)and NO_(3)^(*).The main direct photolysis pathw.ys are defluorination and C–C bond *** addition,the indirect photodegradation of Flu in w.ter is mainly through the reactions w.th·OH and NO_(3)^(*),and the photodegradation reaction w.th CO_(3)^(*-)is relatively difficult to occur in the w.ter *** results provide a theoretical basis for understanding the phototransformation process of Flu in the w.ter environment and assessing its potential risk.

关键词： Fluoxetine Photochemical mechanism Direct photolysis Free radical reaction DFT