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Autonomous Vehicles Testing Considering Utility-Based Operable Tasks 被引量:1
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作者 Jingwei Ge Jiawei Zhang +3 位作者 Yi Zhang Danya Yao Zuo Zhang Rui Zhou 《Tsinghua Science and Technology》 SCIE EI CAS CSCD 2023年第5期965-975,共11页
Virtual simulation testing of Autonomous Vehicles(AVs)is gradually being accepted as a mandatory way to test the feasibility of driving strategies for AVs.Mainstream methods focus on improving testing efficiency by ex... Virtual simulation testing of Autonomous Vehicles(AVs)is gradually being accepted as a mandatory way to test the feasibility of driving strategies for AVs.Mainstream methods focus on improving testing efficiency by extracting critical scenarios from naturalistic driving datasets.However,the criticalities defined in their testing tasks are based on fixed assumptions,the obtained scenarios cannot pose a challenge to AVs with different strategies.To fill this gap,we propose an intelligent testing method based on operable testing tasks.We found that the driving behavior of Surrounding Vehicles(SVs)has a critical impact on AV,which can be used to adjust the testing task difficulty to find more challenging scenarios.To model different driving behaviors,we utilize behavioral utility functions with binary driving strategies.Further,we construct a vehicle interaction model,based on which we theoretically analyze the impact of changing the driving behaviors on the testing task difficulty.Finally,by adjusting SV’s strategies,we can generate more corner cases when testing different AVs in a finite number of simulations. 展开更多
关键词 Autonomous Vehicle(AV) intelligence testing operable tasks
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Hyponormal Block Toeplitz Operators on the Weighted Bergman Space with Circulant Symbols
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作者 FU Guangyang ZHOU Jiang 《数学进展》 北大核心 2026年第1期183-191,共9页
In this paper,we present a necessary and sufficient condition for hyponormal block Toeplitz operators T on the vector-valued weighted Bergman space with symbolsΦ(z)=G^(*)(z)+F(z),where F(z)=∑^(N)_(i)=1 A_(i)z^(i)and... In this paper,we present a necessary and sufficient condition for hyponormal block Toeplitz operators T on the vector-valued weighted Bergman space with symbolsΦ(z)=G^(*)(z)+F(z),where F(z)=∑^(N)_(i)=1 A_(i)z^(i)and G(z)=∑^(N)_(i)=1 A_(−i)z^(i),A_(i)ae culants. 展开更多
关键词 block Toeplitz operator hyponormal weighted Bergman space CIRCULANT COMMUTATOR
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Statistics and Development Analysis of Urban Rail Transit in China by the End of 2025
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作者 WANG Fuwen LIANG Shuaiwen FENG Aijun 《隧道建设(中英文)》 北大核心 2026年第2期437-444,I0005-I0012,共16页
First,statistics on the operational lines and mileage of urban rail transit in China are conducted.The results show that,as of Dec.31,2025,there were 60 cities with urban rail transit in operation nationwide,with a to... First,statistics on the operational lines and mileage of urban rail transit in China are conducted.The results show that,as of Dec.31,2025,there were 60 cities with urban rail transit in operation nationwide,with a total operational mileage of approximately 12837.8 km(excluding the electronic guideway rubber-tired system,there were 57 cities,with a total operational mileage of 12651.6 km).The metro system dominates,while low-capacity systems exhibit a multi-modal development pattern.Subsequently,the characteristics of China′s urban rail transit industry development are analyzed,indicating that:(1)It should closely align with the theme of urban intensive development,promote quality improvement and efficiency enhancement of existing lines,and focus on the supporting role of initial passenger flow for new line construction,multi-network integration,and economic and financial sustainability.(2)Significant innovative achievements have been made in safety resilience,green and low-carbon development,intelligent construction,and digital transformation.Finally,development recommendations for the"15th Five-Year Plan"period are proposed:promoting cost reduction and efficiency improvement in the rail transit industry,enhancing the operational efficiency of existing networks,continuously exploring railway services for urban commuting,strengthening external exchanges,and driving the"going global"strategy of the urban rail transit industry. 展开更多
关键词 rail transit operational lines data statistics development analysis
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Hybrid Controller for Steady Speed of Agricultural Machinery on Slopes
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作者 WU Caicong XU Haisong GAO Xingyu 《农业机械学报》 北大核心 2026年第2期416-426,共11页
Steady speed control of agricultural machinery can improve operating quality and efficiency.To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery,a hybr... Steady speed control of agricultural machinery can improve operating quality and efficiency.To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery,a hybrid control method was proposed.This method included a hybrid controller composed of a slope-based controller and a proportional-integral-derivative(PID)controller.The speed of agricultural machinery was influenced by longitudinal forces,which were divided into two parts:one part was slope-related forces and conventional resistance,and the other was hard-to-estimate forces,such as sliding friction.For the first part,a slope-based controller was designed;for the second part,a PID controller was implemented.By combining these two controllers,the system can dynamically adjust the throttle opening and the brake master cylinder pressure,ensuring steady speed travel on sloping farmland.Simulation tests at a target speed of 7 km/h demonstrated that the proposed controller maintained a stable speed,achieving a root mean square error of 0.13 km/h and a mean absolute percentage error of 1.6%.Field tests on a practical experimental platform validated the method’s effectiveness,with results showing consistent control performance across varying slope conditions.The proposed controller demonstrated superior control performance.Experimental data verified that this method can achieve precise control of the agricultural machinery’s movement speed,meeting the stability requirements for agricultural operations. 展开更多
关键词 farmland slope PID controller steady speed control agricultural machinery unmanned operation
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Cooperative robust parallel operation of multiple actuators
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作者 XU Liang XU Xiang LIU Tao 《控制理论与应用》 北大核心 2026年第1期3-11,共9页
This paper studies cooperative robust parallel operation of multiple actuators over an undirected communication graph.The plant is modeled as an uncertain linear system,and the actuators are linear and identical.Based... This paper studies cooperative robust parallel operation of multiple actuators over an undirected communication graph.The plant is modeled as an uncertain linear system,and the actuators are linear and identical.Based on the internal model principle,a distributed dynamic output feedback control law is proposed to achieve both robust output regulation of the closed-loop system and plant input sharing among the actuators.A practical example of five motors cooperatively driving an uncertain shaft under an external load torque is presented to show the effectiveness of the proposed control law. 展开更多
关键词 cooperative parallel operation multiple actuators robust output regulation CONSENSUS
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Mixed Quasi-martingale Hardy Spaces
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作者 ZHANG Chuanzhou LI Shimeng HE Zhibin 《应用数学》 北大核心 2026年第1期221-231,共11页
In this article,we conduct a study on mixed quasi-martingale Hardy spaces that are defined by means of the mixed L_(p)-norm.By utilizing Doob’s inequalities,we explore the atomic decomposition and quasi-martingale in... In this article,we conduct a study on mixed quasi-martingale Hardy spaces that are defined by means of the mixed L_(p)-norm.By utilizing Doob’s inequalities,we explore the atomic decomposition and quasi-martingale inequalities of mixed quasi-martingale Hardy spaces.Moreover,we furnish sufficient conditions for the boundedness ofσ-sublinear operators in these spaces.These findings extend the existing conclusions regarding mixed quasi-martingale Hardy spaces defined with the help of the mixed L_(p)-norm. 展开更多
关键词 Mixed quasi-martingale Hardy space Atomic Decomposition σ-sublinear operator
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Evaluation of molecular residual disease in operable non-small cell lung cancer with gene fusions,MET exon skipping or de novo MET amplification
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作者 Rui Fu Yuanyuan Xiong +4 位作者 Miao Cai Fang Li Rongrong Chen Yilong Wu Wenzhao Zhong 《Frontiers of Medicine》 SCIE CSCD 2024年第4期735-743,共9页
Gene fusions and MET alterations are rare and difficult to detect in plasma samples.The clinical detection efficacy of molecular residual disease(MRD)based on circulating tumor DNA(ctDNA)in patients with non-small cel... Gene fusions and MET alterations are rare and difficult to detect in plasma samples.The clinical detection efficacy of molecular residual disease(MRD)based on circulating tumor DNA(ctDNA)in patients with non-small cell lung cancer(NSCLC)with these mutations remains unknown.This prospective,non-intervention study recruited 49 patients with operable NSCLC with actionable gene fusions(ALK,ROS1,RET,and FGFR1),MET exon 14 skipping or de novo MET amplification.We analyzed 43 tumor tissues and 111 serial perioperative plasma samples using 1021-and 338-gene panels,respectively.Detectable MRD correlated with a significantly higher recurrence rate(P<0.001),yielding positive predictive values of 100%and 90.9%,and negative predictive values of 82.4%and 86.4%at landmark and longitudinal time points,respectively.Patients with detectable MRD showed reduced disease-free survival(DFS)compared to those with undetectable MRD(P<0.001).Patients who harbored tissue-derived fusion/MET alterations in their MRD had reduced DFS compared to those who did not(P=0.05).To our knowledge,this is the first comprehensive study on ctDNA-MRD clinical detection efficacy in operable NSCLC patients with gene fusions and MET alterations.Patients with detectable tissue-derived fusion/MET alterations in postoperative MRD had worse clinical outcomes. 展开更多
关键词 CTDNA molecular residual disease operable NSCLC gene fusion MET exon skipping MET amplification
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A hierarchical and role-driven digital twin system with applications to complex chemical process operation
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作者 Xinyu Tao Runjie Yao +3 位作者 Lingyu Zhu Changrui Xie Muqian Zhang Xi Chen 《Chinese Journal of Chemical Engineering》 2026年第1期302-313,共12页
Digital twin technology brings more opportunities and challenges to chemical engineering in both academic and industry.A complex process could have multiple digitalization needs,including simulation,monitoring,operato... Digital twin technology brings more opportunities and challenges to chemical engineering in both academic and industry.A complex process could have multiple digitalization needs,including simulation,monitoring,operator training,etc.;thus,a hierarchical digital twin would be a comprehensive solution to that.In this study,a novel and general framework of the digital twin is proposed for operations in process industry.With the hierarchical structure,the framework can handle various tasks driven by different roles in process industry,including managers,engineers,and operators.To complete these tasks,the framework consists of three modules:OAS(Operation Analysis System),OMS(Operation Monitoring System),and OTS(Operator Training System).Each module focuses on one unique type of demand from the staff,as well as interactions among them enabling efficient data sharing.Based on the hierarchical framework,a digital twin system is applied for one complex industrial nitration process,which successfully enhances the operation efficiency and safety in several industrial scenarios with different demands. 展开更多
关键词 Digital twin Hierarchical framework Role-driven Process operation Process modeling&optimization Operator training system
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A Testing Ground
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作者 LI NAN 《China Today》 2026年第2期44-47,共4页
Hainan’s special customs operations are expected to significantly reduce the institutional costs of foreign goods flowing into Hainan,enabling the island to function as a gateway for global goods.DAVID Adrian Janke,a... Hainan’s special customs operations are expected to significantly reduce the institutional costs of foreign goods flowing into Hainan,enabling the island to function as a gateway for global goods.DAVID Adrian Janke,a British citizen operating a translation company in Haikou,capital of Hainan Province in south China,witnessed surging orders as special customs operations got underway in the island province on December 18. 展开更多
关键词 reduce institutional costs global goods foreign goods special customs operations HAINAN customs operations institutional costs translation company
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Hainan FTP:A New Step to Align with International Rules in Opening-Up
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作者 YU YUNQUAN 《China Today》 2026年第3期32-33,共2页
The Hainan Free Trade Port’s implementation of special customs operations marks a significant stride in China’s institutional opening-up,spurring global trade and investment flows.THE Hainan Free Trade Port(FTP)repr... The Hainan Free Trade Port’s implementation of special customs operations marks a significant stride in China’s institutional opening-up,spurring global trade and investment flows.THE Hainan Free Trade Port(FTP)represents a significant step forward in China’s pursuit of high-standard opening-up and greater engagement in economic globalization. 展开更多
关键词 implementation special customs operations Special Customs Operations free trade port s Global Trade Hainan Free Trade Port free trade port ftp represents Institutional Opening Up Investment Flows
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Dexamethasone for prevention of AMS,HACE,and HAPE and for limiting impairment of performance after rapid ascent to high altitude:a narrative review
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作者 Johannes Burtscher Hannes Gatterer +1 位作者 Beth A.Beidleman Martin Burtscher 《Military Medical Research》 2026年第1期159-168,共10页
Acute exposure to high altitude can cause acute altitude illnesses and is associated with impaired cognitive and physical performance.The most effective preventive strategies currently recommended include environmenta... Acute exposure to high altitude can cause acute altitude illnesses and is associated with impaired cognitive and physical performance.The most effective preventive strategies currently recommended include environmental acclimatization(slow ascent and/or pre-acclimatization)or pharmacological support of acclimatization using acetazolamide.However,these strategies are not practical for high-altitude exposures that require rapid and unplanned ascent,high physical and mental performance,such as rescue missions or military operations.Dexamethasone and other modulators of the glucocorticoid system take effect quickly and are effective alternatives for preventing acute altitude illnesses when rapidly ascending to high altitudes.As the efficacy of dexamethasone in preventing acute mountain illnesses remains controversial,a review of existing studies on the use of dexamethasone for the prevention of acute mountain sickness was conducted,aiming to determine the best strategy.Possible mechanisms of protection against acute altitude illnesses are discussed based on the results of clinical trials.The data indicate that dexamethasone is most effective at altitudes above 4000 m at doses of 8–16 mg/d.Appropriately designed and powered trials are needed to obtain more evidence-based results on the dosage and timing of dexamethasone administration,and to provide optimized recommendations for the application of this powerful pharmacological tool. 展开更多
关键词 Altitude illnesses PREVENTION DEXAMETHASONE Emergency Rescue mission Military operation
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A GENERALIZED HILBERT OPERATOR ACTING ON HARDY SPACES
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作者 Huiling CHEN Shanli YE 《Acta Mathematica Scientia》 2026年第1期145-163,共19页
Letα>0 and letμbe a positive Borel measure on the interval[0,1).The Hankel matrix■with entries■induces,formally,the generalized-Hilbert operator■where f(z)■is an analytic function in D.This article is devoted... Letα>0 and letμbe a positive Borel measure on the interval[0,1).The Hankel matrix■with entries■induces,formally,the generalized-Hilbert operator■where f(z)■is an analytic function in D.This article is devoted to study the measuresμfor which Hμ,αis a bounded(resp.,compact)operator from Hp(0<p≤1)into H^(p)(1≤q<∞).We also study the analogous problem in the Hardy spaces H^(p)(1≤p≤2).Finally,we obtain the essential norm of H_(μ,α)from H^(p)(0<p≤1)into H^(p)(1≤q<∞). 展开更多
关键词 Hilbert operator Hardy space Carleson measure essential norm
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A Fractional-Order Study for Bicomplex Haemorrhagic Infection in Several Populations Conditions
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作者 Muhammad Farman Muhammad Hashir Zubair +2 位作者 Hua Li Kottakkaran Sooppy Nisar Mohamad Hafez 《Computer Modeling in Engineering & Sciences》 2026年第1期926-953,共28页
Lassa Fever(LF)is a viral hemorrhagic illness transmitted via rodents and is endemic in West Africa,causing thousands of deaths annually.This study develops a dynamic model of Lassa virus transmission,capturing the pr... Lassa Fever(LF)is a viral hemorrhagic illness transmitted via rodents and is endemic in West Africa,causing thousands of deaths annually.This study develops a dynamic model of Lassa virus transmission,capturing the progression of the disease through susceptible,exposed,infected,and recovered populations.The focus is on simulating this model using the fractional Caputo derivative,allowing both qualitative and quantitative analyses of boundedness,positivity,and solution uniqueness.Fixed-point theory and Lipschitz conditions are employed to confirm the existence and uniqueness of solutions,while Lyapunov functions establish the global stability of both disease-free and endemic equilibria.The study further examines the role of the Caputo operator by solving the generalized power-law kernel via a two-step Lagrange polynomial method.This approach offers practical advantages in handling additional data points in integral forms,though Newton polynomial-based schemes are generally more accurate and can outperform Lagrange-based Adams-Bashforth methods.Graphical simulations validate the proposed numerical approach for different fractional orders(ν)and illustrate the influence of model parameters on disease dynamics.Results indicate that increasing the fractional order accelerates the decline of Lassa fever in both human and rodent populations.Moreover,fractional-order modeling provides more nuanced insights than traditional integer-order models,suggesting potential improvements for medical intervention strategies.The study demonstrates that carefully chosen fractional orders can optimize convergence and enhance the predictive capacity of Lassa fever models,offering a promising direction for future research in epidemiological modeling. 展开更多
关键词 Lassa fever mathematical model caputo fractional operator lyapunov stability
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Control strategies for alkaline water electrolysis hydrogen production:a comprehensive review and future perspectives
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作者 Zihang Dong Xiaojun Shen +2 位作者 Li Wei Alfredo Iranzo Jose I.Leon 《Global Energy Interconnection》 2026年第1期1-28,共28页
Driven by the global energy transition and carbon neutrality targets,alkaline water electrolysis has emerged as a key technology for coupling variable renewable generation with clean hydrogen production,offering consi... Driven by the global energy transition and carbon neutrality targets,alkaline water electrolysis has emerged as a key technology for coupling variable renewable generation with clean hydrogen production,offering considerable potential for absorbing surplus power and enhancing grid flexibility.However,conventional control architectures typically treat the power converter and electrolyzer as independent units,neglecting their dynamic interactions and thereby limiting overall system performance under practical operating conditions.This review critically examines existing control approaches,ranging from classical proportional-integral schemes to model predictive control,fuzzy-logic algorithms,and data-driven methods,evaluating their effectiveness in managing dynamic response,multivariable coupling,and operational constraints as well as their inherent limitations.Attention is then focused on the performance requirements of the hydrogen-production converter,including current ripple suppression,rapid transient response,adaptive thermal regulation,and stable power delivery.An integrated co‑control framework is proposed,aligning converter output with electrolyzer demand across steady-state operation,variable renewable input,and emergency shutdown scenarios to achieve higher efficiency,extended equipment lifetime,and enhanced operational safety.Finally,prospects for advancing unified control methodologies are outlined,with emphasis on constraint-aware predictive control,machine-learning-enhanced modeling,and real‑time co‑optimization for future alkaline electrolyzer systems. 展开更多
关键词 Renewable energy Alkaline water electrolyzer Power electronics Hydrogen production Operational control
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A Q-Learning Improved Particle Swarm Optimization for Aircraft Pulsating Assembly Line Scheduling Problem Considering Skilled Operator Allocation
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作者 Xiaoyu Wen Haohao Liu +6 位作者 Xinyu Zhang Haoqi Wang Yuyan Zhang Guoyong Ye Hongwen Xing Siren Liu Hao Li 《Computers, Materials & Continua》 2026年第1期1503-1529,共27页
Aircraft assembly is characterized by stringent precedence constraints,limited resource availability,spatial restrictions,and a high degree of manual intervention.These factors lead to considerable variability in oper... Aircraft assembly is characterized by stringent precedence constraints,limited resource availability,spatial restrictions,and a high degree of manual intervention.These factors lead to considerable variability in operator workloads and significantly increase the complexity of scheduling.To address this challenge,this study investigates the Aircraft Pulsating Assembly Line Scheduling Problem(APALSP)under skilled operator allocation,with the objective of minimizing assembly completion time.A mathematical model considering skilled operator allocation is developed,and a Q-Learning improved Particle Swarm Optimization algorithm(QLPSO)is proposed.In the algorithm design,a reverse scheduling strategy is adopted to effectively manage large-scale precedence constraints.Moreover,a reverse sequence encoding method is introduced to generate operation sequences,while a time decoding mechanism is employed to determine completion times.The problem is further reformulated as a Markov Decision Process(MDP)with explicitly defined state and action spaces.Within QLPSO,the Q-learning mechanism adaptively adjusts inertia weights and learning factors,thereby achieving a balance between exploration capability and convergence performance.To validate the effectiveness of the proposed approach,extensive computational experiments are conducted on benchmark instances of different scales,including small,medium,large,and ultra-large cases.The results demonstrate that QLPSO consistently delivers stable and high-quality solutions across all scenarios.In ultra-large-scale instances,it improves the best solution by 25.2%compared with the Genetic Algorithm(GA)and enhances the average solution by 16.9%over the Q-learning algorithm,showing clear advantages over the comparative methods.These findings not only confirm the effectiveness of the proposed algorithm but also provide valuable theoretical references and practical guidance for the intelligent scheduling optimization of aircraft pulsating assembly lines. 展开更多
关键词 Aircraft pulsating assembly lines skilled operator reinforcement learning PSO reverse scheduling
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Existence,Uniqueness and Stability of Bounded Solutions for Minkowski-Curvature Problems with Asymptotic Boundary Conditions
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作者 Tianlan CHEN Xuying TANG 《Journal of Mathematical Research with Applications》 2026年第1期57-70,共14页
In this article,we show the existence,uniqueness and stability of bounded solutions to the following quasilinear problems with mean curvature operator(φ'(x′(t)))′=f(t,x),t≥t_(0),lim_(t→∞)x(t)=ψ_(0),lim_(t→... In this article,we show the existence,uniqueness and stability of bounded solutions to the following quasilinear problems with mean curvature operator(φ'(x′(t)))′=f(t,x),t≥t_(0),lim_(t→∞)x(t)=ψ_(0),lim_(t→∞)x′(t)e^(t)=0,where t_(0) and ψ_(0) are real constants,φ(s)=s/√1−s^(2),s∈R with s∈(−1,1),f:[t_(0),∞)×R→R satisfies the Lipschitz or Osgood-type conditions. 展开更多
关键词 mean curvature operator UNIQUENESS asymptotic boundary conditions bounded solution
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λ-BIHARMONIC HYPERSURFACES IN 6-DIMENSIONAL PSEUDO-RIEMANNIAN SPACE FORMS
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作者 DUAN Zhen-ping YANG Chao +1 位作者 LIU Jian-cheng CHEN Jia-rui 《数学杂志》 2026年第1期1-19,共19页
In this paper,we studyλ-biharmonic hypersurfaces M_(r)^(5) of 6-dimensional pseudo Riemannian space form N_(p)^(6)(c)with the indexs 0≤p≤6,r=p−1 or p,and constant curvature c.It was proved that if the shape operato... In this paper,we studyλ-biharmonic hypersurfaces M_(r)^(5) of 6-dimensional pseudo Riemannian space form N_(p)^(6)(c)with the indexs 0≤p≤6,r=p−1 or p,and constant curvature c.It was proved that if the shape operator of M_(r)^(5) is diagonalizable,then the mean curvature is a constant.As an application,we find some types of biharmonic hypersurfaces of N_(p)^(6)(c)are minimal. 展开更多
关键词 λ-biharmonic hypersurface pseudo-Riemannian space form constant mean curvature shape operator minimal
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Automated Pipe Defect Identification in Underwater Robot Imagery with Deep Learning
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作者 Mansour Taheri Andani Farhad Ameri 《哈尔滨工程大学学报(英文版)》 2026年第1期197-215,共19页
Underwater pipeline inspection plays a vital role in the proactive maintenance and management of critical marine infrastructure and subaquatic systems.However,the inspection of underwater pipelines presents a challeng... Underwater pipeline inspection plays a vital role in the proactive maintenance and management of critical marine infrastructure and subaquatic systems.However,the inspection of underwater pipelines presents a challenge due to factors such as light scattering,absorption,restricted visibility,and ambient noise.The advancement of deep learning has introduced powerful techniques for processing large amounts of unstructured and imperfect data collected from underwater environments.This study evaluated the efficacy of the You Only Look Once(YOLO)algorithm,a real-time object detection and localization model based on convolutional neural networks,in identifying and classifying various types of pipeline defects in underwater settings.YOLOv8,the latest evolution in the YOLO family,integrates advanced capabilities,such as anchor-free detection,a cross-stage partial network backbone for efficient feature extraction,and a feature pyramid network+path aggregation network neck for robust multi-scale object detection,which make it particularly well-suited for complex underwater environments.Due to the lack of suitable open-access datasets for underwater pipeline defects,a custom dataset was captured using a remotely operated vehicle in a controlled environment.This application has the following assets available for use.Extensive experimentation demonstrated that YOLOv8 X-Large consistently outperformed other models in terms of pipe defect detection and classification and achieved a strong balance between precision and recall in identifying pipeline cracks,rust,corners,defective welds,flanges,tapes,and holes.This research establishes the baseline performance of YOLOv8 for underwater defect detection and showcases its potential to enhance the reliability and efficiency of pipeline inspection tasks in challenging underwater environments. 展开更多
关键词 YOLO8 Underwater robot Object detection Underwater pipelines Remotely operated vehicle Deep learning
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Splitting of Operations for Di-Associative Algebras and Tri-Associative Algebras
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作者 Wen TENG Xiansheng DAI 《Journal of Mathematical Research with Applications》 2026年第1期21-32,共12页
Loday introduced di-associative algebras and tri-associative algebras motivated by periodicity phenomena in algebraic K-theory.The purpose of this paper is to study the splittings of operations on di-associative algeb... Loday introduced di-associative algebras and tri-associative algebras motivated by periodicity phenomena in algebraic K-theory.The purpose of this paper is to study the splittings of operations on di-associative algebras and tri-associative algebras.We introduce the notion of a quad-dendriform algebra,which is a splitting of a di-associative algebra.We show that a relative averaging operator on dendriform algebras gives rise to a quad-dendriform algebra.Furthermore,we introduce the notion of six-dendriform algebras,which are splittings of the tri-associative algebras,and demonstrate that homomorphic relative averaging operators induce six-dendriform algebras. 展开更多
关键词 dendriform algebra di-associative algebra quad-dendriform algebra tri-associative algebra six-dendriform algebra relative averaging operator
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Performance assessment of long-distance timber extraction in environmentally sensitive areas
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作者 Antonio Zumbo Stanimir Stoilov +3 位作者 Iliya Nenov Georgi Angelov Salvatore F.Papandrea Andrea R.Proto 《Journal of Forestry Research》 2026年第1期329-343,共15页
Sustainable forest management practices frequently confront the tension between economic viability and conservation objectives,particularly where forests occur in environmentally sensitive zones.The use of skidders in... Sustainable forest management practices frequently confront the tension between economic viability and conservation objectives,particularly where forests occur in environmentally sensitive zones.The use of skidders in protected areas is an essential solution for enabling timber harvesting in environments where the establishment of new skidding trails is either prohibited or highly restricted.These machines are the most used timber extraction machines in Central and Eastern Europe,and cable/adapted skidders are used to increase productivity and to reduce labor.This study compared the work cycles,productivity and costs of four types of skidders working in similar coniferous stands:a dedicated cable skidder,a dedicated cable-grapple skidder,a dedicated grapple skidder and an adapted skidder.The comparison of delay-free work cycles of the four skidders showed the largest share is occupied by travel loaded.The cable-grapple skidder had the highest average speed of 5.6 km h^(-1),followed by the grapple skidder at 3.97 km h^(-1),the cable skidder at 3.79 km h^(-1),and the adapted skidder with an average speed of 3.31 km h^(-1).The average delay-free productivity of the study skidders is highest for the adapted skidder,followed by the grapple skidder with a slightly lower rate,the cable-grapple skidder,and the cable skidder.In conclusion,the average payload of the grapple skidder and the cable grapple skidder is less than the maximum payload of the machine.This is due to the narrow skidding roads and because these skidders are not suitable for the specific site-selective felling with marked single and small groups of trees.The dedicated cable skidders and the adapted cable skidder are very close in productivity.The average productivity of dedicated cable skidders was 17.7 m^(3) h^(-1),while the productivity of the adapted skidder is 14.5 m^(3) h^(-1).Considering this,adapted skidders could be a good solution for improving economic productivity in sensitive forests. 展开更多
关键词 Natura 2000 Sustainable forest management Forest operations Productivity and costs
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