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A regime-switching stochastic SIR epidemic model with a saturated incidence and limited medical resources

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生物数学学报:英文版 2023年第7期16卷 91-110页

作者： wei wei wei Xu Jiankang Liu Department of Applied Mathematics Northwestern Polytechnical University Xi'an 710072 ShaanciP.R.China

The stochastic switching SIR epidemic model with saturated incidence and limited medical treatment is investigated in this paper.By using Lyapunov methods and Ito formula,we first prove that the system has a unique global positive solution with any positive initial value.Then combining inequality technique and the ergodic property of Markov switching,the suficient conditions for extinction and persistence in the mean of the disease are established.The results demonstrate that increasing medical resources and improving supply efficiency can accelerate the transition from the persistent state to the extinct state.Meanwhile,the high incidence rate will slow down the extinction of the disease.Specially,the switching noise can induce the system to toggle between the extinct and persistent states.Finally,some numerical simulations are carried out to confirm the analytical results.

关键词： Epidemic model extinction persistence Markov switching saturated incidence

Super solutions of the model RB

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Frontiers of Computer Science 2022年第6期16卷 191-193页

作者： Guangyan ZHOU wei Xu Department of Mathematics Beijing Technology and Business UniversityBeijing 100048China School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China

1 Introduction Constraint satisfaction problems(CSPs)have come to play a prominent role in the area of computer science,statistical physics and information theory.A CSP instance involves a set of variables and a set of constraints,and the task is to find a solution(an assignment of variables that satisfies all the constraints)or to prove the unsolvability.Model RB[1]is a CSP model proposed to overcome the trivial unsatisfiability of standard Model B[2].

关键词： theory. constraints trivial

Interactions between water and organic molecules or inorganic salts on surfaces

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Aggregate 2022年第4期3卷 61-72页

作者： Chi Zhang wei Xu Interdisciplinary Materials Research Center College of Materials Science and EngineeringTongji UniversityShanghaiPeople’s Republic of China

Water,as a ubiquitous and relatively inert medium,plays a vital role in nature.The interactions between water and organic molecules or inorganic salts are of fundamental interest in understanding hydration processes in chemistry.The combination of scanning probe microscopy and theoretical calculations provides a versatile tool to directly visualize and further rationalize such interactions as well as influences of water on organic molecules and inorganic salts.In this review,we provide a brief overview of the recent exciting progress in revealing the interactions between water and organic molecules as well as inorganic salts(including ions)on surfaces.Herein,we describe first steps of hydration of organic molecules followed by a microsolvation process on surfaces.Subsequently,water-induced tautomerization and chiral separation of small biomolecules on surfaces are discussed for understanding the roles of water in driving biological self-assembly processes.Moreover,water is also able to assist structural transformation globally by selectively interrupting the relatively weak hydrogen bonds within nanostructures.Based on the water-incorporated molecular nanostructures,dissolution of sodium halides on wet surfaces is achievable using confined water,while hydrates of halide ions desorb from the surface.More interestingly,ion hydrates are also demonstrated to be artificially accessible,which enables atomic-scale investigation into local ion hydration and transport at interfaces.This review provides new insights into the role of water in the hydrationrelated molecular and ionic systems,with implications for hydration and solvent effects down to the single-molecule level.

关键词： density functional theory hydration hydrogen bonds scanning probe microscopy water

A New Method for Estimating Lithium‑Ion Battery State‑of‑Energy Based on Multi‑timescale Filter

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Automotive Innovation 2023年第4期6卷 611-621页

作者： Guangming Zhao wei Xu Yifan Wang Road Traffic Safety Research Center of the Ministry of Public Security Beijing 100068China China Automotive Engineering Research Institute Co. LtdChongqing 401120China

Accurate estimation of the state-of-energy(SOE)in lithium-ion batteries is critical for optimal energy management and energy optimization in electric vehicles.However,the conventional recursive least squares(RLS)algorithm struggle to track changes in battery model parameters under dynamic conditions.To address this,a multi-timescale estimator is proposed.A variable forgetting factor RLS approach is used to determine the model parameters at a macro timescale,and the H infinity filter is utilized to estimate the SOE at a micro timescale.The proposed algorithm is verified and analyzed and shown to have accurate and robust identification of battery model parameters.Finally,experiments under dynamic cycles demonstrate that the proposed algorithm has a high level of accuracy for SOE estimation.

关键词： Forgetting factor State-of-energy Multi-timescale Lithium-ion battery

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体外膜肺氧合期间儿童脑功能监测与预后评估

中国实用儿科杂志 2022年第3期37卷 189-194页

作者：文广富许巍中国医科大学附属盛京医院儿科辽宁沈阳110004

近年来,体外膜肺氧合(extracorporeal membrane oxygenation, ECMO)患儿脑部并发症相关报道增多,除出血、梗死、癫痫发作和脑灌注不足等常见并发症,还有其他尚不明确但相关的损伤和临床表现,并在短期内影响ECMO患儿的预后乃至决定ECMO... 详细信息

近年来,体外膜肺氧合(extracorporeal membrane oxygenation, ECMO)患儿脑部并发症相关报道增多,除出血、梗死、癫痫发作和脑灌注不足等常见并发症,还有其他尚不明确但相关的损伤和临床表现,并在短期内影响ECMO患儿的预后乃至决定ECMO治疗是否成功,因此脑功能监测显得尤为重要,已成为ECMO患者管理的要素之一。此外,人们逐渐认识到,神经系统并发症可能不只发生在早期阶段,ECMO患儿也易并发长期神经认知功能不良事件,如学习、工作障碍。但目前在ECMO患儿脑功能监测方面还未形成统一的临床管理策略和方案,尤其患儿出院后的神经认知功能和神经心理随访,需要更系统更科学的管理流程。

关键词：体外膜肺氧合脑功能监测脑梗死颅内出血儿童

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CES Transactions on Electrical Machines and Systems 2022年第2期6卷 111-112页

作者： wei Xu State Key Laboratory of Advanced Electromagnetic Engineering in Huazhong University of Science and Technology Hefei University of Technology Southwest Jiaotong University Tanta University University of Sydney Jiangsu University Nanjing University of Aeronautics and Astronautics Beijing Jiaotong University Harbin Institute of Technology Politehnica University Timisoara the Institute of Engineering and Technology (IET) Southeast University Zhejiang University Naval University of Engineering Tongji University

COMPARED with the rotary machines,the linear machines can get linear motion independent on the intermediate transmission device,which can benefit from advantages of higher acceleration/deceleration,faster dynamic response,higher precision,lower maintenance,lower noise,smaller volume or size,and so on.Till now,the linear machines have been widely adopted to industrial applications requiring linear movement,such as linear metros,MAGLEVs,servo systems,wave-energy generators,conveyors,linear compressor,fast action solenoids,loudspeakers,microphones,etc.,which have great potentiality and huge market in future.

关键词： faster acceleration action

Control of epileptic activities in a cortex network of multiple coupled neural populations under electromagnetic induction

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Applied Mathematics and Mechanics(English Edition) 2023年第3期44卷 499-514页

作者： Zhongkui SUN Yuanyuan LIU Xiaoli YANG wei Xu School of Mathematics and Statistics Northwestern Polytechnical UniversityXi’an 710129China School of Mathematics and Statistics Shaanxi Normal UniversityXi’an 710062China

Epilepsy is believed to be associated with the abnormal synchronous neuronal activity in the brain,which results from large groups or circuits of neurons.In this paper,we choose to focus on the temporal lobe epilepsy,and establish a cortex network of multiple coupled neural populations to explore the epileptic activities under electromagnetic induction.We demonstrate that the epileptic activities can be controlled and modulated by electromagnetic induction and coupling among regions.In certain regions,these two types of control are observed to show exactly reverse effects.The results show that the strong electromagnetic induction is conducive to eliminating the epileptic seizures.The coupling among regions has a conduction effect that the previous normal background activity of the region gives way to the epileptic discharge,owing to coupling with spike wave discharge regions.Overall,these results highlight the role of electromagnetic induction and coupling among the regions in controlling and modulating epileptic activities,and might provide novel insights into the treatments of epilepsy.

关键词： epilepsy electromagnetic induction multiple coupled neural population dynamical transition

Significance of two different ranking methods for studying fish fauna:a case study on the fish fauna from upper and middle portions from Mekong River

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Integrative Zoology 2023年第2期18卷 316-332页

作者： wei ZHOU xu LI Key Laboratory for Conserving Wildlife with Small Populations in Yunnan Southwest Forestry UniversityKunmingChina

Studies onﬁsh fauna should not only focus onﬁsh composition and the comparison ofﬁsh composition among the study region and adjacent regions,but should also explore the origin and uniqueness of different taxa as well as the substitution of genera and species.In this study,the value ofﬂoristic presence method was modiﬁed and renamed the value ofﬁsh fauna presence(VFFP)method.The speciﬁc steps of the VFFP method and the traditionalﬁsh fauna analysis(TFFA)method were reﬁned and standardized.Then,the VFFP and TFFA methods were applied to study theﬁsh fauna of the upper and middle portions of the Mekong River basin.The results indicate that the TFFA method reﬂects the families(subfamilies)and genera that constitute the main body ofﬁsh in the studied river basin.The results of the VFFP method show which families(subfamilies)and genera are representative for the basin.Therefore,combining the TFFA and VFFP methods to analyze the composition ofﬁsh fauna can reﬂect the characteristics ofﬁsh fauna from different perspectives.The case study shows that theﬁsh fauna of the Mekong River is a part of theﬁsh fauna of Southeast Asia.Although it shows some similarities to the composition of South Asianﬁsh fauna,it does not belong to the South Asianﬁsh fauna as a whole,and is essentially different from the East Asianﬁsh fauna.This study provides an objective,quantitative,and veriﬁable method for studyingﬁsh fauna.

关键词： ﬁsh composition ranking Southeast Asia traditionalﬁsh fauna analysis value ofﬁsh fauna presence

A Dynamic Resource Allocation Strategy with Reinforcement Learning for Multimodal Multi-objective Optimization

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Machine Intelligence Research 2022年第2期19卷 138-152页

作者： Qian-Long Dang wei Xu Yang-Fei Yuan School of Mathematics and Statistics Xidian UniversityXi’an 710126China

Many isolation approaches, such as zoning search, have been proposed to preserve the diversity in the decision space of multimodal multi-objective optimization(MMO). However, these approaches allocate the same computing resources for subspaces with different difficulties and evolution states. In order to solve this issue, this paper proposes a dynamic resource allocation strategy(DRAS)with reinforcement learning for multimodal multi-objective optimization problems(MMOPs). In DRAS, relative contribution and improvement are utilized to define the aptitude of subspaces, which can capture the potentials of subspaces accurately. Moreover, the reinforcement learning method is used to dynamically allocate computing resources for each subspace. In addition, the proposed DRAS is applied to zoning searches. Experimental results demonstrate that DRAS can effectively assist zoning search in finding more and better distributed equivalent Pareto optimal solutions in the decision space.

关键词： Multimodal multi-objective optimization(MMO) dynamic resource allocating strategy(DRAS) reinforcement learning(RL) decision space partition zoning search