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An Improved Reinforcement Learning-Based 6G UAV Communication for Smart Cities
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作者 Vi Hoai Nam Chu Thi Minh Hue Dang Van Anh 《Computers, Materials & Continua》 2026年第1期2030-2044,共15页
Unmanned Aerial Vehicles(UAVs)have become integral components in smart city infrastructures,supporting applications such as emergency response,surveillance,and data collection.However,the high mobility and dynamic top... Unmanned Aerial Vehicles(UAVs)have become integral components in smart city infrastructures,supporting applications such as emergency response,surveillance,and data collection.However,the high mobility and dynamic topology of Flying Ad Hoc Networks(FANETs)present significant challenges for maintaining reliable,low-latency communication.Conventional geographic routing protocols often struggle in situations where link quality varies and mobility patterns are unpredictable.To overcome these limitations,this paper proposes an improved routing protocol based on reinforcement learning.This new approach integrates Q-learning with mechanisms that are both link-aware and mobility-aware.The proposed method optimizes the selection of relay nodes by using an adaptive reward function that takes into account energy consumption,delay,and link quality.Additionally,a Kalman filter is integrated to predict UAV mobility,improving the stability of communication links under dynamic network conditions.Simulation experiments were conducted using realistic scenarios,varying the number of UAVs to assess scalability.An analysis was conducted on key performance metrics,including the packet delivery ratio,end-to-end delay,and total energy consumption.The results demonstrate that the proposed approach significantly improves the packet delivery ratio by 12%–15%and reduces delay by up to 25.5%when compared to conventional GEO and QGEO protocols.However,this improvement comes at the cost of higher energy consumption due to additional computations and control overhead.Despite this trade-off,the proposed solution ensures reliable and efficient communication,making it well-suited for large-scale UAV networks operating in complex urban environments. 展开更多
关键词 UAV FANET smart cities reinforcement learning Q-LEARNING
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Computer Modeling of Pipeline Repair Reinforcement with Composite Bandages
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作者 Maria Tanase Gennadiy Lvov 《Computer Modeling in Engineering & Sciences》 2026年第2期296-315,共20页
The increasing occurrence of corrosion-related damage in steel pipelines has led to the growing use of composite-based repair techniques as an efficient alternative to traditional replacement methods.Computer modeling... The increasing occurrence of corrosion-related damage in steel pipelines has led to the growing use of composite-based repair techniques as an efficient alternative to traditional replacement methods.Computer modeling and structural analysis were performed for the repair reinforcement of a steel pipeline with a composite bandage.A preliminary analysis of possible contact interaction schemes was implemented based on the theory of cylindrical shells,taking into account transverse shear deformations.The finite element method was used for a detailed study of the stress state of the composite bandage and the reinforced section of the pipeline.The limit state of the reinforced section was assessed based on the von Mises criterion for steel and the Tsai-Wu criterion for composites.The effectiveness of the repair was demonstrated on a pipeline whose wall thickness had decreased by 20%as a result of corrosion damage.At a nominal pressure of P=6 MPa,the maximum normal stress in the weakened area reached 381 MPa.The installation of a composite bandage reduced this stress to 312 MPa,making the repaired section virtually as strong as the undamaged pipeline.Due to the linearity of the problem,the results obtained can be easily used to find critical internal pressure values. 展开更多
关键词 Numerical analysis pipeline repair reinforceMENT composite bandages
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Research on UAV-MEC Cooperative Scheduling Algorithms Based on Multi-Agent Deep Reinforcement Learning
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作者 Yonghua Huo Ying Liu +1 位作者 Anni Jiang Yang Yang 《Computers, Materials & Continua》 2026年第3期1823-1850,共28页
With the advent of sixth-generation mobile communications(6G),space-air-ground integrated networks have become mainstream.This paper focuses on collaborative scheduling for mobile edge computing(MEC)under a three-tier... With the advent of sixth-generation mobile communications(6G),space-air-ground integrated networks have become mainstream.This paper focuses on collaborative scheduling for mobile edge computing(MEC)under a three-tier heterogeneous architecture composed of mobile devices,unmanned aerial vehicles(UAVs),and macro base stations(BSs).This scenario typically faces fast channel fading,dynamic computational loads,and energy constraints,whereas classical queuing-theoretic or convex-optimization approaches struggle to yield robust solutions in highly dynamic settings.To address this issue,we formulate a multi-agent Markov decision process(MDP)for an air-ground-fused MEC system,unify link selection,bandwidth/power allocation,and task offloading into a continuous action space and propose a joint scheduling strategy that is based on an improved MATD3 algorithm.The improvements include Alternating Layer Normalization(ALN)in the actor to suppress gradient variance,Residual Orthogonalization(RO)in the critic to reduce the correlation between the twin Q-value estimates,and a dynamic-temperature reward to enable adaptive trade-offs during training.On a multi-user,dual-link simulation platform,we conduct ablation and baseline comparisons.The results reveal that the proposed method has better convergence and stability.Compared with MADDPG,TD3,and DSAC,our algorithm achieves more robust performance across key metrics. 展开更多
关键词 UAV-MEC networks multi-agent deep reinforcement learning MATD3 task offloading
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Evaluation of Reinforcement Learning-Based Adaptive Modulation in Shallow Sea Acoustic Communication
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作者 Yifan Qiu Xiaoyu Yang +1 位作者 Feng Tong Dongsheng Chen 《哈尔滨工程大学学报(英文版)》 2026年第1期292-299,共8页
While reinforcement learning-based underwater acoustic adaptive modulation shows promise for enabling environment-adaptive communication as supported by extensive simulation-based research,its practical performance re... While reinforcement learning-based underwater acoustic adaptive modulation shows promise for enabling environment-adaptive communication as supported by extensive simulation-based research,its practical performance remains underexplored in field investigations.To evaluate the practical applicability of this emerging technique in adverse shallow sea channels,a field experiment was conducted using three communication modes:orthogonal frequency division multiplexing(OFDM),M-ary frequency-shift keying(MFSK),and direct sequence spread spectrum(DSSS)for reinforcement learning-driven adaptive modulation.Specifically,a Q-learning method is used to select the optimal modulation mode according to the channel quality quantified by signal-to-noise ratio,multipath spread length,and Doppler frequency offset.Experimental results demonstrate that the reinforcement learning-based adaptive modulation scheme outperformed fixed threshold detection in terms of total throughput and average bit error rate,surpassing conventional adaptive modulation strategies. 展开更多
关键词 Adaptive modulation Shallow sea underwater acoustic modulation reinforcement learning
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A Deep Reinforcement Learning-Based Partitioning Method for Power System Parallel Restoration
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作者 Changcheng Li Weimeng Chang +1 位作者 Dahai Zhang Jinghan He 《Energy Engineering》 2026年第1期243-264,共22页
Effective partitioning is crucial for enabling parallel restoration of power systems after blackouts.This paper proposes a novel partitioning method based on deep reinforcement learning.First,the partitioning decision... Effective partitioning is crucial for enabling parallel restoration of power systems after blackouts.This paper proposes a novel partitioning method based on deep reinforcement learning.First,the partitioning decision process is formulated as a Markov decision process(MDP)model to maximize the modularity.Corresponding key partitioning constraints on parallel restoration are considered.Second,based on the partitioning objective and constraints,the reward function of the partitioning MDP model is set by adopting a relative deviation normalization scheme to reduce mutual interference between the reward and penalty in the reward function.The soft bonus scaling mechanism is introduced to mitigate overestimation caused by abrupt jumps in the reward.Then,the deep Q network method is applied to solve the partitioning MDP model and generate partitioning schemes.Two experience replay buffers are employed to speed up the training process of the method.Finally,case studies on the IEEE 39-bus test system demonstrate that the proposed method can generate a high-modularity partitioning result that meets all key partitioning constraints,thereby improving the parallelism and reliability of the restoration process.Moreover,simulation results demonstrate that an appropriate discount factor is crucial for ensuring both the convergence speed and the stability of the partitioning training. 展开更多
关键词 Partitioning method parallel restoration deep reinforcement learning experience replay buffer partitioning modularity
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Effect of inertial and kinematic interaction on seismic behavior of cement-soil reinforced pile in liquefiable sites
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作者 YANG Song-song ZHANG Ding-wen +1 位作者 LI Hong-jiang WANG An-hui 《Journal of Central South University》 2026年第1期202-223,共22页
A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stre... A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stress−strain hysteresis curves of soil profiles on the pile side with and without cement-soil reinforced piles indicates that cement-soil reinforced piles not only bear more tremendous shear stress but also have smaller strains under the action of cyclic shear stress.Furthermore,the cement-soil on the pile side not only shares part of the shear stress and modifies the bending moment distribution but also significantly enhances the resistance of the pile-side soil,reducing the lateral displacement of the superstructure.Cement-soil reinforcement reduced shear strains,inhibited sand liquefaction,and reduced superstructure displacements by 27%−47%(instantaneous)and 40%−65%(permanent).The proportion of horizontal load sharing between cement-soil reinforcement and saturated sand is considered,along with the change pattern of the subgrade reaction after sand liquefaction.An equivalent subgrade reaction calculation method is proposed,which accounts for the horizontal load-sharing ratios of soils with two different strengths.The test results indicate that the pile stress and displacement,estimated using the equivalent subgrade reaction,are in good agreement with the observed results. 展开更多
关键词 LIQUEFACTION cement-soil reinforced piles inertial force kinematic force equivalent subgrade reaction pseudo-static analysis
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A Multi-Objective Deep Reinforcement Learning Algorithm for Computation Offloading in Internet of Vehicles
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作者 Junjun Ren Guoqiang Chen +1 位作者 Zheng-Yi Chai Dong Yuan 《Computers, Materials & Continua》 2026年第1期2111-2136,共26页
Vehicle Edge Computing(VEC)and Cloud Computing(CC)significantly enhance the processing efficiency of delay-sensitive and computation-intensive applications by offloading compute-intensive tasks from resource-constrain... Vehicle Edge Computing(VEC)and Cloud Computing(CC)significantly enhance the processing efficiency of delay-sensitive and computation-intensive applications by offloading compute-intensive tasks from resource-constrained onboard devices to nearby Roadside Unit(RSU),thereby achieving lower delay and energy consumption.However,due to the limited storage capacity and energy budget of RSUs,it is challenging to meet the demands of the highly dynamic Internet of Vehicles(IoV)environment.Therefore,determining reasonable service caching and computation offloading strategies is crucial.To address this,this paper proposes a joint service caching scheme for cloud-edge collaborative IoV computation offloading.By modeling the dynamic optimization problem using Markov Decision Processes(MDP),the scheme jointly optimizes task delay,energy consumption,load balancing,and privacy entropy to achieve better quality of service.Additionally,a dynamic adaptive multi-objective deep reinforcement learning algorithm is proposed.Each Double Deep Q-Network(DDQN)agent obtains rewards for different objectives based on distinct reward functions and dynamically updates the objective weights by learning the value changes between objectives using Radial Basis Function Networks(RBFN),thereby efficiently approximating the Pareto-optimal decisions for multiple objectives.Extensive experiments demonstrate that the proposed algorithm can better coordinate the three-tier computing resources of cloud,edge,and vehicles.Compared to existing algorithms,the proposed method reduces task delay and energy consumption by 10.64%and 5.1%,respectively. 展开更多
关键词 Deep reinforcement learning internet of vehicles multi-objective optimization cloud-edge computing computation offloading service caching
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Accurate closed-form flutter eigensolutions of three-dimensional composite laminates with shear deformation
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作者 Dezhuang PAN Yufeng XING 《Chinese Journal of Aeronautics》 2026年第1期230-246,共17页
According to the Mindlin plate theory and the first-order piston theory,this work obtains accurate closed-form eigensolutions for the flutter problem of three-dimensional(3D)rectangular laminated panels.The governing ... According to the Mindlin plate theory and the first-order piston theory,this work obtains accurate closed-form eigensolutions for the flutter problem of three-dimensional(3D)rectangular laminated panels.The governing differential equations are derived by the Hamilton's variational principle,and then solved by the iterative Separation-of-Variable(i SOV)method,which are applicable to arbitrary combinations of homogeneous Boundary Conditions(BCs).However,only the simply-support,clamped and cantilever panels are considered in this work for the sake of clarity.With the closed-form eigensolutions,the flutter frequency,flutter mode and flutter boundary are presented,and the effect of shear deformation and aerodynamic damping on flutter frequencies is investigated.Besides,the relation between panel energy and the work of aerodynamic load is discussed.The numerical comparisons reveal the following.(A)The flutter eigenvalues obtained by the present method are accurate,validated by the Finite Element Method(FEM)and the Galerkin method.(B)When the span-chord ratio is larger than 3,simplifying a 3D panel to 2D(two-dimensional)panel is reasonable and the relative differences of the flutter points predicted by the two models are less than one percent.(C)The reciprocal relationship between the mechanical energy of the panel and the work done by aerodynamic load is verified by using the present flutter eigenvalues and modes,further indicating the high accuracy of the present solutions.(D)The coupling of shear deformation and aerodynamic damping prevents frequency coalescing. 展开更多
关键词 Closed-form eigensolutions The first-order piston theory The Mindlin plate theory three-dimensional panel flutter Separation-of-variable method
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Beyond Wi-Fi 7:Enhanced Decentralized Wireless Local Area Networks with Federated Reinforcement Learning
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作者 Rashid Ali Alaa Omran Almagrabi 《Computers, Materials & Continua》 2026年第3期391-409,共19页
Wi-Fi technology has evolved significantly since its introduction in 1997,advancing to Wi-Fi 6 as the latest standard,with Wi-Fi 7 currently under development.Despite these advancements,integrating machine learning in... Wi-Fi technology has evolved significantly since its introduction in 1997,advancing to Wi-Fi 6 as the latest standard,with Wi-Fi 7 currently under development.Despite these advancements,integrating machine learning into Wi-Fi networks remains challenging,especially in decentralized environments with multiple access points(mAPs).This paper is a short review that summarizes the potential applications of federated reinforcement learning(FRL)across eight key areas of Wi-Fi functionality,including channel access,link adaptation,beamforming,multi-user transmissions,channel bonding,multi-link operation,spatial reuse,and multi-basic servic set(multi-BSS)coordination.FRL is highlighted as a promising framework for enabling decentralized training and decision-making while preserving data privacy.To illustrate its role in practice,we present a case study on link activation in a multi-link operation(MLO)environment with multiple APs.Through theoretical discussion and simulation results,the study demonstrates how FRL can improve performance and reliability,paving the way for more adaptive and collaborative Wi-Fi networks in the era of Wi-Fi 7 and beyond. 展开更多
关键词 Artificial intelligence reinforcement learning channels selection wireless local area networks 802.11ax 802.11be WI-FI
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Deep reinforcement learning-based adaptive collision avoidance method for UAV in joint operational airspace
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作者 Yan Shen Xuejun Zhang +1 位作者 Yan Li Weidong Zhang 《Defence Technology(防务技术)》 2026年第2期142-159,共18页
As joint operations have become a key trend in modern military development,unmanned aerial vehicles(UAVs)play an increasingly important role in enhancing the intelligence and responsiveness of combat systems.However,t... As joint operations have become a key trend in modern military development,unmanned aerial vehicles(UAVs)play an increasingly important role in enhancing the intelligence and responsiveness of combat systems.However,the heterogeneity of aircraft,partial observability,and dynamic uncertainty in operational airspace pose significant challenges to autonomous collision avoidance using traditional methods.To address these issues,this paper proposes an adaptive collision avoidance approach for UAVs based on deep reinforcement learning.First,a unified uncertainty model incorporating dynamic wind fields is constructed to capture the complexity of joint operational environments.Then,to effectively handle the heterogeneity between manned and unmanned aircraft and the limitations of dynamic observations,a sector-based partial observation mechanism is designed.A Dynamic Threat Prioritization Assessment algorithm is also proposed to evaluate potential collision threats from multiple dimensions,including time to closest approach,minimum separation distance,and aircraft type.Furthermore,a Hierarchical Prioritized Experience Replay(HPER)mechanism is introduced,which classifies experience samples into high,medium,and low priority levels to preferentially sample critical experiences,thereby improving learning efficiency and accelerating policy convergence.Simulation results show that the proposed HPER-D3QN algorithm outperforms existing methods in terms of learning speed,environmental adaptability,and robustness,significantly enhancing collision avoidance performance and convergence rate.Finally,transfer experiments on a high-fidelity battlefield airspace simulation platform validate the proposed method's deployment potential and practical applicability in complex,real-world joint operational scenarios. 展开更多
关键词 Unmanned aerial vehicle Collision avoidance Deep reinforcement learning Joint operational airspace Hierarchical prioritized experience replay
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Energy Optimization for Autonomous Mobile Robot Path Planning Based on Deep Reinforcement Learning
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作者 Longfei Gao Weidong Wang Dieyun Ke 《Computers, Materials & Continua》 2026年第1期984-998,共15页
At present,energy consumption is one of the main bottlenecks in autonomous mobile robot development.To address the challenge of high energy consumption in path planning for autonomous mobile robots navigating unknown ... At present,energy consumption is one of the main bottlenecks in autonomous mobile robot development.To address the challenge of high energy consumption in path planning for autonomous mobile robots navigating unknown and complex environments,this paper proposes an Attention-Enhanced Dueling Deep Q-Network(ADDueling DQN),which integrates a multi-head attention mechanism and a prioritized experience replay strategy into a Dueling-DQN reinforcement learning framework.A multi-objective reward function,centered on energy efficiency,is designed to comprehensively consider path length,terrain slope,motion smoothness,and obstacle avoidance,enabling optimal low-energy trajectory generation in 3D space from the source.The incorporation of a multihead attention mechanism allows the model to dynamically focus on energy-critical state features—such as slope gradients and obstacle density—thereby significantly improving its ability to recognize and avoid energy-intensive paths.Additionally,the prioritized experience replay mechanism accelerates learning from key decision-making experiences,suppressing inefficient exploration and guiding the policy toward low-energy solutions more rapidly.The effectiveness of the proposed path planning algorithm is validated through simulation experiments conducted in multiple off-road scenarios.Results demonstrate that AD-Dueling DQN consistently achieves the lowest average energy consumption across all tested environments.Moreover,the proposed method exhibits faster convergence and greater training stability compared to baseline algorithms,highlighting its global optimization capability under energy-aware objectives in complex terrains.This study offers an efficient and scalable intelligent control strategy for the development of energy-conscious autonomous navigation systems. 展开更多
关键词 Autonomous mobile robot deep reinforcement learning energy optimization multi-attention mechanism prioritized experience replay dueling deep Q-Network
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A State-of-the-Art Survey of Adversarial Reinforcement Learning for IoT Intrusion Detection
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作者 Qasem Abu Al-Haija Shahad Al Tamimi 《Computers, Materials & Continua》 2026年第4期26-94,共69页
Adversarial Reinforcement Learning(ARL)models for intelligent devices and Network Intrusion Detection Systems(NIDS)improve systemresilience against sophisticated cyber-attacks.As a core component of ARL,Adversarial Tr... Adversarial Reinforcement Learning(ARL)models for intelligent devices and Network Intrusion Detection Systems(NIDS)improve systemresilience against sophisticated cyber-attacks.As a core component of ARL,Adversarial Training(AT)enables NIDS agents to discover and prevent newattack paths by exposing them to competing examples,thereby increasing detection accuracy,reducing False Positives(FPs),and enhancing network security.To develop robust decision-making capabilities for real-world network disruptions and hostile activity,NIDS agents are trained in adversarial scenarios to monitor the current state and notify management of any abnormal or malicious activity.The accuracy and timeliness of the IDS were crucial to the network’s availability and reliability at this time.This paper analyzes ARL applications in NIDS,revealing State-of-The-Art(SoTA)methodology,issues,and future research prospects.This includes Reinforcement Machine Learning(RML)-based NIDS,which enables an agent to interact with the environment to achieve a goal,andDeep Reinforcement Learning(DRL)-based NIDS,which can solve complex decision-making problems.Additionally,this survey study addresses cybersecurity adversarial circumstances and their importance for ARL and NIDS.Architectural design,RL algorithms,feature representation,and training methodologies are examined in the ARL-NIDS study.This comprehensive study evaluates ARL for intelligent NIDS research,benefiting cybersecurity researchers,practitioners,and policymakers.The report promotes cybersecurity defense research and innovation. 展开更多
关键词 reinforcement learning network intrusion detection adversarial training deep learning cybersecurity defense intrusion detection system and machine learning
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Noise-driven enhancement for exploration:Deep reinforcement learning for UAV autonomous navigation in complex environments
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作者 Haotian ZHANG Yiyang LI +1 位作者 Lingquan CHENG Jianliang AI 《Chinese Journal of Aeronautics》 2026年第1期454-471,共18页
Unmanned Aerial Vehicle(UAV)plays a prominent role in various fields,and autonomous navigation is a crucial component of UAV intelligence.Deep Reinforcement Learning(DRL)has expanded the research avenues for addressin... Unmanned Aerial Vehicle(UAV)plays a prominent role in various fields,and autonomous navigation is a crucial component of UAV intelligence.Deep Reinforcement Learning(DRL)has expanded the research avenues for addressing challenges in autonomous navigation.Nonetheless,challenges persist,including getting stuck in local optima,consuming excessive computations during action space exploration,and neglecting deterministic experience.This paper proposes a noise-driven enhancement strategy.In accordance with the overall learning phases,a global noise control method is designed,while a differentiated local noise control method is developed by analyzing the exploration demands of four typical situations encountered by UAV during navigation.Both methods are integrated into a dual-model for noise control to regulate action space exploration.Furthermore,noise dual experience replay buffers are designed to optimize the rational utilization of both deterministic and noisy experience.In uncertain environments,based on the Twin Delay Deep Deterministic Policy Gradient(TD3)algorithm with Long Short-Term Memory(LSTM)network and Priority Experience Replay(PER),a Noise-Driven Enhancement Priority Memory TD3(NDE-PMTD3)is developed.We established a simulation environment to compare different algorithms,and the performance of the algorithms is analyzed in various scenarios.The training results indicate that the proposed algorithm accelerates the convergence speed and enhances the convergence stability.In test experiments,the proposed algorithm successfully and efficiently performs autonomous navigation tasks in diverse environments,demonstrating superior generalization results. 展开更多
关键词 Action space exploration Autonomous navigation Deep reinforcement learning Twin delay deep deterministic policy gradient Unmanned aerial vehicle
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AquaTree:Deep Reinforcement Learning-Driven Monte Carlo Tree Search for Underwater Image Enhancement
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作者 Chao Li Jianing Wang +1 位作者 Caichang Ding Zhiwei Ye 《Computers, Materials & Continua》 2026年第3期1444-1464,共21页
Underwater images frequently suffer from chromatic distortion,blurred details,and low contrast,posing significant challenges for enhancement.This paper introduces AquaTree,a novel underwater image enhancement(UIE)meth... Underwater images frequently suffer from chromatic distortion,blurred details,and low contrast,posing significant challenges for enhancement.This paper introduces AquaTree,a novel underwater image enhancement(UIE)method that reformulates the task as a Markov Decision Process(MDP)through the integration of Monte Carlo Tree Search(MCTS)and deep reinforcement learning(DRL).The framework employs an action space of 25 enhancement operators,strategically grouped for basic attribute adjustment,color component balance,correction,and deblurring.Exploration within MCTS is guided by a dual-branch convolutional network,enabling intelligent sequential operator selection.Our core contributions include:(1)a multimodal state representation combining CIELab color histograms with deep perceptual features,(2)a dual-objective reward mechanism optimizing chromatic fidelity and perceptual consistency,and(3)an alternating training strategy co-optimizing enhancement sequences and network parameters.We further propose two inference schemes:an MCTS-based approach prioritizing accuracy at higher computational cost,and an efficient network policy enabling real-time processing with minimal quality loss.Comprehensive evaluations on the UIEB Dataset and Color correction and haze removal comparisons on the U45 Dataset demonstrate AquaTree’s superiority,significantly outperforming nine state-of-the-art methods across five established underwater image quality metrics. 展开更多
关键词 Underwater image enhancement(UIE) Monte Carlo tree search(MCTS) deep reinforcement learning(DRL) Markov decision process(MDP)
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Fabrication and Properties of Three-dimensional Braided Carbon Fiber Reinforced SiO2-rich Mullite Composites 被引量:2
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作者 ZHANG Wei MA Qingsong MAO Weiguo 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2019年第4期798-803,共6页
In order to enhance the fracture toughness of mullite, three-dimensional braided carbon fiber reinforced mullite(C/mullite) composites were prepared using the Al2O3-SiO2 sol with a high solid content as raw material. ... In order to enhance the fracture toughness of mullite, three-dimensional braided carbon fiber reinforced mullite(C/mullite) composites were prepared using the Al2O3-SiO2 sol with a high solid content as raw material. Mullitization behavior of the sol was characterized. Then, the microstructure, mechanical properties and oxidation resistance of C/mullite composites were investigated. It is found that the SiO2-rich mullite with desirable sintering shrinkage can be synthesized at 1 300 ℃ from the sol with an Al2O3/SiO2 mass ratio of 1:1. The C/mullite composites with a total porosity of 21.5% were fabricated by repeating 18 cycles of vacuum impregnation-drying-heat treatment, showing a flexural strength of 234.5 MPa and a fracture toughness of 13.1 MPa·m1/2. Since carbon fibers were protected by compact matrix, the C/mullite composites show favorable oxidation resistance during 1 200 ℃-1 600 ℃ even if an open porosity of 10.3% was detected. 展开更多
关键词 MULLITE carbon fiber reinforceMENT SOL mechanical properties OXIDATION resistance
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Three-dimensional analysis of slopes reinforced with piles 被引量:11
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作者 高玉峰 叶茂 张飞 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第6期2322-2327,共6页
Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of... Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of the factor of safety. Parametric studies were carried out to explore the end effects of the slope failures and the effects of the pile location and diameter on the safety of the reinforced slopes. The results demonstrate that the end effects nearly have no effects on the most suitable location of the installed piles but have significant influence on the safety of the slopes. For a slope constrained to a narrow width, the slope becomes more stable owing to the contribution of the end effects. When the slope is reinforced with a row of piles in small space between piles, the effects of group piles are significant for evaluating the safety of slopes. The presented method is more appropriate for assessing the stability of slopes reinforced with piles and can be also utilized in the design of plies stabilizing the unstable slopes. 展开更多
关键词 three-dimensional rotational failure mechanism stability of slopes limit analysis LANDSLIDES PILES
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Preparation of Three-Dimensional Carbon Network Reinforced Epoxy Composites and Their Thermal Conductivity 被引量:1
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作者 Jing Li Kai Song +4 位作者 Hetong Zhang Yue Guo Fang He Naiqin Zhao Chunsheng Shi 《Transactions of Tianjin University》 EI CAS 2020年第5期399-408,共10页
As a thermosetting resin with excellent properties,epoxy resin is used in many areas such as electronics,transportation,aerospace,and other fields.However,its relatively low thermal conductivity limits its wide applic... As a thermosetting resin with excellent properties,epoxy resin is used in many areas such as electronics,transportation,aerospace,and other fields.However,its relatively low thermal conductivity limits its wide application in more demanding fields.Here,a three-dimensional carbon(3DC)network was prepared through NaCl template-assisted in situ chemical vapor deposition(CVD)and used to reinforce epoxy resin for enhancing its thermal conductivity.The 3DC was prepared with a molar ratio of sodium atom to carbon atom of 100:20,and argon atmosphere in CVD led to an optimal improvement in the thermal conductivity of epoxy resin.The thermal conductivity of epoxy resin increased by 18%when the filling content was 3 wt.%of 3DC network because of the high contact area,uniform dispersion,and enhanced formation of conductive paths with epoxy resin.As the amount of 3DC addition increases,the thermal conductivity of composites also increases.As an innovative exploration,the work presented in this paper is of great significance for the thermal conductivity application of epoxy resin in the future. 展开更多
关键词 three-dimensional carbon NaCl template Epoxy resin Composites Thermal conductivity
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Microstructure-based three-dimensional characterization of chip formation and surface generation in the machining of particulate-reinforced metal matrix composites 被引量:3
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作者 Qi Wu Liangchi Zhang 《International Journal of Extreme Manufacturing》 EI 2020年第4期74-85,共12页
Particulate-reinforced metal matrix composites(PRMMCs)are difficult to machine due to the inclusion of hard,brittle reinforcing particles.Existing experimental investigations rarely reveal the complex material removal... Particulate-reinforced metal matrix composites(PRMMCs)are difficult to machine due to the inclusion of hard,brittle reinforcing particles.Existing experimental investigations rarely reveal the complex material removal mechanisms(MRMs)involved in the machining of PRMMCs.This paper develops a three-dimensional(3D)microstructure-based model for investigating the MRM and surface integrity of machined PRMMCs.To accurately mimic the actual microstructure of a PRMMC,polyhedrons were randomly distributed inside the matrix to represent irregular SiC particles.Particle fracture and matrix deformation and failure were taken into account.For the model’s capability comparison,a two-dimensional(2D)analysis was also conducted.Relevant cutting experiments showed that the established 3D model accurately predicted the material removal,chip morphology,machined surface finish,and cutting forces.It was found that the matrix-particle-tool interactions led to particle fractures,mainly in the primary shear and secondary deformation zones along the cutting path and beneath the machined surface.Particle fracture and dilodegment greatly influences the quality of a machined surface.It was also found that although a 2D model can reflect certain material removal features,its ability to predict microstructural variation is limited. 展开更多
关键词 particulate-reinforced metal-matrix composites MMCS finite element three-dimensional modelling particle fracture material removal surface integrity
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Preparation of three-dimensional braided carbon fiber reinforced mullite composites from a sol with high solid content 被引量:1
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作者 Wei ZHANG Qing-song MA +1 位作者 Ke-wei DAI Wei-guo MAO 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第11期2249-2255,共7页
To prepare the three-dimensional braided carbon fiber reinforced mullite (3D C/mullite) composites, an Al2O3-SiO2 solwith a solid content of 20% (mass fraction) and an Al2O3/SiO2 mass ratio of 2:1 was selected as... To prepare the three-dimensional braided carbon fiber reinforced mullite (3D C/mullite) composites, an Al2O3-SiO2 solwith a solid content of 20% (mass fraction) and an Al2O3/SiO2 mass ratio of 2:1 was selected as the raw material. Characteristics andmullitization of the sol were analyzed throughly. It is found that the formation of mullite is basically completed at 1300℃ and thegel powders exhibit favorable sintering shrinkage. The 3D C/mullite composites without interfacial coating were fabricated throughthe route of vacuum impregnation-drying-heat treatment. Satisfied mechanical properties with a flexural strength of 241.2 MPa anda fracture toughness of 10.9 MPa·m1/2are obtained although the total porosity reaches 26.0%. Oxidation resistances of the compositesat 1200, 1400 and 1600 ℃ were investigated. Due to the further densification of matrix, the 3D C/mullite composites show tiny massloss and their mechanical properties are well retained after oxidation at 1600 ℃ for 30 min. 展开更多
关键词 carbon fiber reinforced mullite composites Al2O3-SiO2 sol mechanical properties oxidation resistance
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Approximate error correction scheme for three-dimensional surface codes based reinforcement learning
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作者 曲英杰 陈钊 +1 位作者 王伟杰 马鸿洋 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第10期229-240,共12页
Quantum error correction technology is an important method to eliminate errors during the operation of quantum computers.In order to solve the problem of influence of errors on physical qubits,we propose an approximat... Quantum error correction technology is an important method to eliminate errors during the operation of quantum computers.In order to solve the problem of influence of errors on physical qubits,we propose an approximate error correction scheme that performs dimension mapping operations on surface codes.This error correction scheme utilizes the topological properties of error correction codes to map the surface code dimension to three dimensions.Compared to previous error correction schemes,the present three-dimensional surface code exhibits good scalability due to its higher redundancy and more efficient error correction capabilities.By reducing the number of ancilla qubits required for error correction,this approach achieves savings in measurement space and reduces resource consumption costs.In order to improve the decoding efficiency and solve the problem of the correlation between the surface code stabilizer and the 3D space after dimension mapping,we employ a reinforcement learning(RL)decoder based on deep Q-learning,which enables faster identification of the optimal syndrome and achieves better thresholds through conditional optimization.Compared to the minimum weight perfect matching decoding,the threshold of the RL trained model reaches 0.78%,which is 56%higher and enables large-scale fault-tolerant quantum computation. 展开更多
关键词 fault-tolerant quantum computing surface code approximate error correction reinforcement learning
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