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Resource Allocation in Multi-User Cellular Networks:A Transformer-Based Deep Reinforcement Learning Approach

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China Communications 2024年第5期21卷 77-96页

作者： Zhao Di Zheng Zhong qin Pengfei qin Hao song Bin State Key Laboratory of Integrated Services Networks Xidian University710071China China Academy of Space Technology Beijing 100081China

To meet the communication services with diverse requirements,dynamic resource allocation has shown increasing *** this paper,we consider the multi-slot and multi-user resource allocation(MSMU-RA)in a downlink cellular scenario with the aim of maximizing system spectral efficiency while guaranteeing user *** first model the MSMURA problem as a dual-sequence decision-making process,and then solve it by a novel Transformerbased deep reinforcement learning(TDRL)***,the proposed TDRL approach can be achieved based on two aspects:1)To adapt to the dynamic wireless environment,the proximal policy optimization(PPO)algorithm is used to optimize the multi-slot RA strategy.2)To avoid co-channel interference,the Transformer-based PPO algorithm is presented to obtain the optimal multi-user RA scheme by exploring the mapping between user sequence and resource *** results show that:i)the proposed approach outperforms both the traditional and DRL methods in spectral efficiency and user fairness,ii)the proposed algorithm is superior to DRL approaches in terms of convergence speed and generalization performance.

关键词： dynamic resource allocation multi-user cellular network spectrum efficiency user fairness

Random Forest-Based Fatigue Reliability-Based Design Optimization for Aeroengine Structures

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 665-684页

作者： Xue-qin Li Lu-Kai song School of Energy and Power Engineering Beihang UniversityBeijing100191China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityKowloonHong Kong999077China Research Institute of Aero-Engine Beihang UniversityBeijing100191China

Fatigue reliability-based design optimization of aeroengine structures involves multiple repeated calculations of reliability degree and large-scale calls of implicit high-nonlinearity limit state function,leading to the traditional direct Monte Claro and surrogate methods prone to unacceptable computing efficiency and *** this case,by fusing the random subspace strategy and weight allocation technology into bagging ensemble theory,a random forest(RF)model is presented to enhance the computing efficiency of reliability degree;moreover,by embedding the RF model into multilevel optimization model,an efficient RF-assisted fatigue reliability-based design optimization framework is *** the low-cycle fatigue reliability-based design optimization of aeroengine turbine disc as a case,the effectiveness of the presented framework is *** reliabilitybased design optimization results exhibit that the proposed framework holds high computing accuracy and computing *** current efforts shed a light on the theory/method development of reliability-based design optimization of complex engineering structures.

关键词： Random forest reliability-based design optimization ensemble learning machine learning

Reproductive biology of Hemitripterus villosus in the Bohai Strait,China

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Journal of Oceanology and Limnology 2024年第3期42卷 881-892页

作者： Ping SUN song qin Zhengyi LIU Longchuan ZHUANG Key Laboratory of Coastal Biology and Biological Resource Utilization Yantai Institute of Coastal Zone ResearchChinese Academy of SciencesYantai 264003China University of Chinese Academy of Sciences Beijing 100049China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

To understand the reproductive biology of Hemitripterus villosus in the Bohai Strait,and fill the key knowledge gap in verifying reproductive seasonality and documenting gonadotropin dependent reproductive cycle of this species,a year-round detail study was conducted for the first *** total,263 individuals were randomly sampled off the coasts of the Bohai *** show that and the overall female-to-male ratio(1.35:1)did not differ significantly from the 1:1 sex *** length and weight relationship for females and males were regressed,depicting an isometric growth for both *** reproductive phases of the complete gonadotropin dependent reproductive cycle in both sexes were *** monthly variations in the gonadosomatic and hepatosomatic indexes for both sexes further indicated that this species spawns a single batch of eggs per year and the peak spawning period is from October to *** average diameter of eggs ranged from 2.10 to 3.57 *** length at first sexual maturity was 224.87 mm for females and 241.26 mm for *** positive relationships between absolute fecundity and fish size,and also gonadal weight were *** from the Bohai Strait exhibited smaller body size,smaller egg diameter,lower gonadosomatic index,lower absolute fecundity,and higher population extinction risk than the other populations’studied *** findings contribute to understanding the status of this isolated westernmost population,and we emphasize that more efficient protection measures for the species and control measures are urgently required to improve the coastal environment in the Bohai Strait.

关键词： Hemitripterus villosus Bohai Strait fecundity length at first maturity reproductive seasonality

Empirical likelihood for spatial cross-sectional data models with matrix exponential spatial specification

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 125-139页

作者： LIU Yan RONG Jian-rong qin Yong-song Nanning University Nanning 530200China Center for Applied Mathematics of Guangxi and College of Mathematics and Statistics Guangxi Normal UniversityGuilin 541004China

In this paper,we study spatial cross-sectional data models in the form of matrix exponential spatial specification(MESS),where MESS appears in both dependent and error *** empirical likelihood(EL)ratio statistics are established for the parameters of the MESS *** is shown that the limiting distributions of EL ratio statistics follow chi-square distributions,which are used to construct the confidence regions of model *** experiments are conducted to compare the performances of confidence regions based on EL method and normal approximation method.

关键词： MESS empirical likelihood con dence region

Tetrabromobisphenol A exerts thyroid disrupting effects but has little overt impact on postnatal brain development and neurobehaviors in mice

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Journal of Environmental Sciences 2024年第8期142卷 1-10页

作者： Shilin song Yuanyuan Li Lin Lv Mengqi Dong Zhanfen qin State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China School of Environment Tsinghua UniversityBeijing 100084China

Tetrabromobisphenol A(TBBPA)is a widely used brominated flame *** is evidence showing that TBBPA can exert thyroid disrupting effects in mammals,but different results were also reported,along with inconsistent reports regarding its ***,we investigated thyroid disrupting effects and neurotoxicity of TBBPA(5,50,500μg/(kg·day))to male mice following maternal and direct exposure through drinking water,with the antithyroid drug propylthiouracil(PTU)as the positive *** postnatal day(PND)15,we expectedly observed severe thyroid compensatory hyperplasia and cerebellar developmental retardation in PTU-treated *** highest dose of TBBPA also caused thyroid histological alteration but had no effects on cerebellar development in terms of Purkinje cell morphology and the thickness of the internal granular layer and the molecular layer of the *** puberty and adulthood,the thyroid morphological alterations became more pronounced in the TBBPA-treated animals,accompanied by decreased serum thyroid hormone ***,the 50 and 500μg/(kg·day)TBBPA groups showed a significant decrease in the serum level of serotonin,a neurotransmitter associated with anxiety ***,the highest dose group displayed anxiety-like behaviors in the elevated plus-maze test on PND 35,but this neurobehavioral alteration disappeared on PND ***,no changes in neurobehavioral parameters tested were found in TBBPAtreated animals at puberty and ***,all observations show that TBBPA can exert thyroid disrupting effects but has little overt impact on brain development and neurobehaviors in mice,suggesting that thyroid disruption does not necessarily cause overtly adverse neurodevelopmental outcomes.

关键词： Tetrabromobisphenol A Thyroid disruption Brain development Neurobehavior Cerebellum

Ultrathin ternary PtNiGa nanowires for enhanced oxygen reduction reaction

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Chinese Chemical Letters 2024年第2期35卷 599-603页

作者： Giday Fisseha Yiping Hu Yanan Yu Shaojie Lu Dongsheng Ma Pei nian Zheng Wang qin Yue Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering School of Chemistry and Chemical EngineeringNingxia UniversityYinchuan 750021China

Achieving high activity and durability for the oxygen reduction reaction(ORR)with an ultra-low amount of platinum is significant to promote the widespread application of proton exchange membrane fuel cells(PEMFCs).Here we report a new ultrathin(∼1 nm)ternary PtNiGa alloy nanowires(PtNiGa NWs)electrocatalyst,in which the presence of gallium(Ga)enhances the oxidation resistance of platinum(Pt)and nickel(Ni)and suppresses the dissolution of *** mass and specific activities of PtNiGa NWs are about 11.2 and 7.6 times higher than those of commercial Pt/C catalysts for ***,the mass activity of PtNiGa/C NWs nanocatalyst decreased only by 12.8%and largely retained its electrochemical surface area(ECSA)after 10,000 potential cycles,compared with 38%loss of ECSA for commercial Pt/C ***,this work provides a general guideline for preparing ternary alloy electrocatalysts and enhancing the activity and stability of the cathode ORR reaction of PEMFCs.

关键词： Ultrathin nanowires Gallium Oxygen reduction reaction Ternary alloy Durability

Dynamic Coupling Analysis of Semisubmersible Platform Float-over Method for Docking Case

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Journal of Ocean University of China 2024年第2期23卷 345-357页

作者： DING Hongyan qin Licheng ZHANG Puyang song Zhengrong XIE Weiwei State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China Offshore Oil Engineering Co. Ltd.Tianjin 300461China

In this paper,the multi-body coupled dynamic characteristics of a semisubmersible platform and an HYSY 229 barge were ***,coupled hydrodynamic analysis of the HYSY 229 barge and the semisubmersible platform was *** hydrodynamic parameters were obtained using the retardation function method of three-dimensional frequency-domain potential flow *** results of the hydrodynamic analysis were highly consistent with the test findings,verifying the accuracy of the multifloating hydrodynamic coupling analysis,and key hydrodynamic parameters were solved for different water depths and the coupling *** to the obtained results,the hydrodynamic influence was the largest in shallow waters when the coupling effect was ***,the coupled motion equation combined with viscous damping,fender system,and mooring system was established,and the hydrodynamics,floating body motion,and dynamic response of the fender system were *** analysis revealed good agreement among the surge,sway,and yaw motions of the two floating ***,when the wave period reached 10 s,the motion of the two floating bodies showed severe shock,and a relative motion was also ***,excessive constraints should be added between the two floating bodies during construction to ensure construction *** numerical analysis and model test results of the semisubmersible platform and HYSY 229 barge at a water depth of 42 m and sea conditions of 0°,45°,and 90° were in good agreement,and the error was less than 5%.The maximum movement of the HYSY 229 barge reached 2.61 m in the sway direction,whereas that of the semisubmersible platform was 2.11 *** construction,excessive constraints should be added between the two floating bodies to limit their relative movement and ensure construction safety.

关键词： float-over method semisubmersible platform coupling hydrodynamic fender system time-domain analysis

Experimental and numerical investigation of the impacts of rotor tip-rake on excitation forces of pump-jet propulsors

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Journal of Hydrodynamics 2024年第1期36卷 142-157页

作者： Xue-qin Ji Xiao-song Zhang Chen-jun Yang Xiao-qian Dong State Key Laboratory of Ocean Engineering Marine Numerical Experiment CentreSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China CSSC Shanghai Marine Energy Saving Technology Co. Ltd.Shanghai200011China China Ship Scientific Research Center Shanghai Branch Shanghai200011China

The tip-clearance flow in a pump-jet propulsor exerts great impacts on the fluctuating pressures and resultant unsteady forces,which are important sources of structural vibrations and radiated noise *** blade geometry close to the tip is an important factor determining the vortex strength in the tip-clearance *** the open-water condition,the effects of raking the rotor tips on the duct-surface fluctuating pressures and the resultant unsteady forces acting on different components of the propulsor are investigated via physical model experiments and the numerical solution of Reynolds-averaged Navier-Stokes(RANS)equations coupled with the SST k-ωturbulence *** measured and simulated results of hydrodynamic pressures are consistent to each other,and the simulated flows help better understand why the fluctuating pressures change with the tip *** strong fluctuations of duct-surface pressures are caused by intensive tip separation *** duct-surface pressure fluctuations are effectively reduced by using the rake distribution near the tip towards blade back side and,for the combination of the five-bladed rotor and the seven-bladed stator,the resultant unsteady horizontal(and vertical)forces acting on the duct and stator are also reduced;while increasing rake leads to negative effect on pressure fluctuations and unsteady horizontal(and vertical)forces acting on all the components of the propulsor.

关键词： Pump-jet tip-clearance tip-rake fluctuating pressures excitation forces

Research on Evacuation Path Planning Based on Improved Sparrow Search Algorithm

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1295-1316页

作者： Xiaoge Wei Yuming Zhang Huaitao song Hengjie qin Guanjun Zhao The School of Building Environment Engineering Zhengzhou University of Light IndustryZhengzhou450001China Zhengzhou Key Laboratory of Electric Power Fire Safety Zhengzhou University of Light IndustryZhengzhou450001China Eccom Network System Shanghai201103China

Reducing casualties and property losses through effective evacuation route planning has been a key focus for researchers in recent *** part of this effort,an enhanced sparrow search algorithm(MSSA)was ***,the Golden Sine algorithm and a nonlinear weight factor optimization strategy were added in the discoverer position update stage of the SSA ***,the Cauchy-Gaussian perturbation was applied to the optimal position of the SSA algorithm to improve its ability to jump out of local ***,the local search mechanism based on the mountain climbing method was incorporated into the local search stage of the SSA algorithm,improving its local search *** evaluate the effectiveness of the proposed algorithm,the Whale Algorithm,Gray Wolf Algorithm,Improved Gray Wolf Algorithm,Sparrow Search Algorithm,and MSSA Algorithm were employed to solve various test *** accuracy and convergence speed of each algorithm were then compared and *** results indicate that the MSSA algorithm has superior solving ability and stability compared to other *** further validate the enhanced algorithm’s capabilities for path planning,evacuation experiments were conducted using different maps featuring various obstacle ***,a multi-exit evacuation scenario was constructed according to the actual building environment of a teaching *** the sparrow search algorithm and MSSA algorithm were employed in the simulation experiment for multiexit evacuation path *** findings demonstrate that the MSSA algorithm outperforms the comparison algorithm,showcasing its greater advantages and higher application potential.

关键词： Sparrow search algorithm optimization and improvement function test set evacuation path planning