期刊文献+
共找到3,222篇文章
< 1 2 162 >
每页显示 20 50 100
Beyond origin:multimodal AI synthesis to resolve cancers of unknown primary
1
作者 Hongru Shen Xiangchun Li 《Cancer Biology & Medicine》 2026年第1期21-29,共9页
For decades,the central dogma of oncology has been that a cancer’s identity is inextricably linked to its anatomical origin.This principle underpins the entire diagnostic and therapeutic framework,from histology-base... For decades,the central dogma of oncology has been that a cancer’s identity is inextricably linked to its anatomical origin.This principle underpins the entire diagnostic and therapeutic framework,from histology-based classification to site-specific treatment guidelines.Yet,this framework catastrophically fails for a substantial population of patients diagnosed with cancer of unknown primary(CUP).These patients present metastatic disease,yet their primary tumors remain elusive despite exhaustive clinical workup1.CUP,accounting for 1%-3%of all cancer diagnoses,is an enigma with devastating consequences;the median overall survival is only 2-12 months2-4.The inability to pinpoint an origin forces clinicians to rely on broad-spectrum empirical chemotherapy,such as taxane-carboplatin regimens,which have limited efficacy and exclude patients from the promise of targeted therapies and clinical trials5.CUP is not only a diagnostic challenge but also an indictment of the siloed approach to understanding malignancy:this cancer highlights the limitations of origin-based diagnostic frameworks.However,the confluence of high-dimensional biological data and advanced artificial intelligence(AI)is now poised to address this long-standing diagnostic limitation and to herald a new era for not only CUP but also oncology as a whole(Figure 1). 展开更多
关键词 central dogma oncology cancer unknown primary high dimensional biological data clinical trials diagnostic framework artificial intelligence targeted therapies multimodal AI synthesis
暂未订购
Compensation for Heterogeneous Unknowns and Performance-Prescribed Consensus
2
作者 Linzhen Yu Yungang Liu 《IEEE/CAA Journal of Automatica Sinica》 2025年第1期173-182,共10页
In this paper, the multi-agent systems(MASs) typically with heterogeneous unknown nonlinearities and nonidentical unknown control coefficients are studied. Although the model information of MASs is coarse, the leader-... In this paper, the multi-agent systems(MASs) typically with heterogeneous unknown nonlinearities and nonidentical unknown control coefficients are studied. Although the model information of MASs is coarse, the leader-following consensus is still pursued, with a prescribed performance and zero consensus errors. Leveraging a powerful funnel control strategy, a fully distributed and completely relative-state-dependent protocol is designed. Distinctively, the time-varying function characterizing the performance boundary is introduced, not only to construct the funnel gains but also as an indispensable part of the protocol,enhancing the control ability and enabling the consensus errors to converge to zero(rather than a residual set). Remark that when control directions are unknown, coexisting with inherent system nonlinearities, it is essential to incorporate an additional compensation mechanism while imposing a hierarchical structure of communication topology for the control design and analysis. Simulation examples are given to illustrate the effectiveness of the theoretical results. 展开更多
关键词 Fully distributed protocol funnel control nonidentical unknown control directions performance-prescribed consensus unknown heterogeneous nonlinearities
在线阅读 下载PDF
Evaluating fever of unknown origin definitions in a tertiary care setting:Implications for diagnostic criteria revision
3
作者 Pathik Dhangar Prasan Kumar Panda +6 位作者 Ravi Kant Rohit Gupta Ruchi Dua Ashutosh Tiwari Sandeep Saini Kavita Khoiwal Yogesh Bahurupi 《World Journal of Experimental Medicine》 2025年第2期103-108,共6页
BACKGROUND Fever of unknown origin(FUO)remains a diagnostic challenge and was originally defined in 1961.Its classic criteria include fever≥38.3°C(≥101°F)on multiple occasions,fever lasting three weeks or ... BACKGROUND Fever of unknown origin(FUO)remains a diagnostic challenge and was originally defined in 1961.Its classic criteria include fever≥38.3°C(≥101°F)on multiple occasions,fever lasting three weeks or longer,and a diagnosis after one week of inpatient evaluation.However,these criteria may not fully encompass the varied clinical presentations seen in resource-limited settings such as India.The adaptation of FUO definitions to local healthcare contexts is crucial for enhancing diagnostic accuracy and optimizing patient outcomes.AIM To investigate the applicability of revised FUO criteria in a tertiary care setting in India.METHODS This longitudinal-exploratory study at All India Institute of Medical Sciences Rishikesh(January 2018–December 2022)analyzed 228 adult patients with fever≥99.1°F lasting over three days.Patients diagnosed within three days of admission were excluded.Data were collected retrospectively and prospectively using predefined FUO definitions based on durations of nondiagnosis(3-21 days,>21 days),temperature ranges(99.1°F-100.9°F,≥101°F),and hospitalization durations(3-7 days,>7 days).Descriptive statistics and comparative tests(Fisher's exact test,χ2 test)evaluated outcomes across definitions.RESULTS Among the proposed FUO definitions,Definition B(fever lasting 3-21 days,temperatures between 99.1°F-100.9°F,hospitalization>7 days)predominated(40.8%),while only 2.2%met the classical criteria.Notably,36.5%of Definition B patients remained undiagnosed after 7-10 days,despite 94%undergoing diagnostic workups within 21 days.Infection emerged as the leading etiology across definitions,without significant variation in outcomes or mortality during hospitalization(χ2=27.937,P=0.142).CONCLUSION Adapting FUO criteria to local contexts improves diagnostic accuracy and treatment.Definition B(40.8%prevalence)showed practical utility,with higher mortality in patients discharged on empirical'Anti-tuberculosis therapy'. 展开更多
关键词 Empirical therapy New definition Pyrexia of unknown origin TUBERCULOSIS
暂未订购
Monocular visual estimation for autonomous aircraft landing guidance in unknown structured scenes
4
作者 Zhuo ZHANG Quanrui CHEN +2 位作者 Qiufu WANG Xiaoliang SUN Qifeng YU 《Chinese Journal of Aeronautics》 2025年第9期365-382,共18页
The autonomous landing guidance of fixed-wing aircraft in unknown structured scenes presents a substantial technological challenge,particularly regarding the effectiveness of solutions for monocular visual relative po... The autonomous landing guidance of fixed-wing aircraft in unknown structured scenes presents a substantial technological challenge,particularly regarding the effectiveness of solutions for monocular visual relative pose estimation.This study proposes a novel airborne monocular visual estimation method based on structured scene features to address this challenge.First,a multitask neural network model is established for segmentation,depth estimation,and slope estimation on monocular images.And a monocular image comprehensive three-dimensional information metric is designed,encompassing length,span,flatness,and slope information.Subsequently,structured edge features are leveraged to filter candidate landing regions adaptively.By leveraging the three-dimensional information metric,the optimal landing region is accurately and efficiently identified.Finally,sparse two-dimensional key point is used to parameterize the optimal landing region for the first time and a high-precision relative pose estimation is achieved.Additional measurement information is introduced to provide the autonomous landing guidance information between the aircraft and the optimal landing region.Experimental results obtained from both synthetic and real data demonstrate the effectiveness of the proposed method in monocular pose estimation for autonomous aircraft landing guidance in unknown structured scenes. 展开更多
关键词 Automatic landing Image processing Monocular camera Pose measurement unknown structured scene
原文传递
Diagnostic utility of sepsis screening tools,procalcitonin,and Creactive protein in nosocomial fever of unknown origin
5
作者 Shashikant Saini Sapna Pahil +3 位作者 Ritin Mohindra Naresh Sachdeva Navneet Sharma Ashok K Pannu 《World Journal of Critical Care Medicine》 2025年第3期251-262,共12页
BACKGROUND Nosocomial fever of unknown origin(nFUO)is a frequent and challenging diagnostic entity,encompassing diverse infectious and non-infectious etiologies.Timely identification is crucial,yet evidence on the dia... BACKGROUND Nosocomial fever of unknown origin(nFUO)is a frequent and challenging diagnostic entity,encompassing diverse infectious and non-infectious etiologies.Timely identification is crucial,yet evidence on the diagnostic accuracy of commonly employed sepsis screening tools and biomarkers remains sparse.We hypothesized that these tools and biomarkers measured at fever onset could distinguish infectious from non-infectious causes of nFUO in critically ill adults.AIM To evaluate the diagnostic utility of sepsis tools and biomarkers in identifying infectious causes of nFUO.METHODS This prospective observational study included patients admitted to the Acute Care Emergency Medicine Unit,Postgraduate Institute of Medical Education and Research,Chandigarh,India(July 2023 to December 2024).nFUO was defined by Durack and Street criteria.Diagnostic performance of sepsis screening tools(systemic inflammatory response syndrome,Sequential Organ Failure Assessment,quick Sequential Organ Failure Assessment,National Early Warning Score,and Modified Early Warning Score)and biomarkers[procalcitonin(PCT),C-reactive protein(CRP)]at fever onset was assessed using receiver operating characteristic curve analysis.RESULTS Of 80 cases(mean age 42.9±16.5 years;80% male),42.5% had infectious causes,38.7% non-infectious,and 18.8% remained undiagnosed.Pneumonia(26.2%)and bloodstream infections(11.2%)were the most common infectious etiologies,while central fever and thrombophlebitis(each 7.5%)were predominant among non-infectious causes.Sepsis tools showed poor diagnostic accuracy,with area under the receiver operating characteristic curve(AUC)values close to 0.5.PCT demonstrated modest performance(AUC=0.61;optimal cut-off:0.85μg/L),while CRP was paradoxically higher in non-infectious cases(AUC=0.45).Overall mortality was 20% and was highest among undiagnosed patients(33.3%).Fever duration and hospitalization length were significantly greater in infectious cases.CONCLUSION Sepsis tools,PCT,and CRP have limited utility in identifying infectious causes of nFUO in critically ill adults and should not solely guide initial decision-making. 展开更多
关键词 Critical care Fever of unknown origin NOSOCOMIAL SEPSIS Screening tools PROCALCITONIN C-reactive protein
暂未订购
Decentralised adaptive learning-based control of robot manipulators with unknown parameters
6
作者 Emil Mühlbradt Sveen Jing Zhou +1 位作者 Morten Kjeld Ebbesen Mohammad Poursina 《Journal of Automation and Intelligence》 2025年第2期136-144,共9页
This paper studies motor joint control of a 4-degree-of-freedom(DoF)robotic manipulator using learning-based Adaptive Dynamic Programming(ADP)approach.The manipulator’s dynamics are modelled as an open-loop 4-link se... This paper studies motor joint control of a 4-degree-of-freedom(DoF)robotic manipulator using learning-based Adaptive Dynamic Programming(ADP)approach.The manipulator’s dynamics are modelled as an open-loop 4-link serial kinematic chain with 4 Degrees of Freedom(DoF).Decentralised optimal controllers are designed for each link using ADP approach based on a set of cost matrices and data collected from exploration trajectories.The proposed control strategy employs an off-line,off-policy iterative approach to derive four optimal control policies,one for each joint,under exploration strategies.The objective of the controller is to control the position of each joint.Simulation and experimental results show that four independent optimal controllers are found,each under similar exploration strategies,and the proposed ADP approach successfully yields optimal linear control policies despite the presence of these complexities.The experimental results conducted on the Quanser Qarm robotic platform demonstrate the effectiveness of the proposed ADP controllers in handling significant dynamic nonlinearities,such as actuation limitations,output saturation,and filter delays. 展开更多
关键词 Adaptive dynamic programming Optimal control Robot manipulator 4-DoF unknown dynamics
在线阅读 下载PDF
A Compact Manifold Mixup Feature-Based Open-Set Recognition Approach for Unknown Signals
7
作者 Yang Ying Zhu Lidong +1 位作者 Li Chengjie Sun Hong 《China Communications》 2025年第4期322-338,共17页
There are all kinds of unknown and known signals in the actual electromagnetic environment,which hinders the development of practical cognitive radio applications.However,most existing signal recognition models are di... There are all kinds of unknown and known signals in the actual electromagnetic environment,which hinders the development of practical cognitive radio applications.However,most existing signal recognition models are difficult to discover unknown signals while recognizing known ones.In this paper,a compact manifold mixup feature-based open-set recognition approach(OR-CMMF)is proposed to address the above problem.First,the proposed approach utilizes the center loss to constrain decision boundaries so that it obtains the compact latent signal feature representations and extends the low-confidence feature space.Second,the latent signal feature representations are used to construct synthetic representations as substitutes for unknown categories of signals.Then,these constructed representations can occupy the extended low-confidence space.Finally,the proposed approach applies the distillation loss to adjust the decision boundaries between the known categories signals and the constructed unknown categories substitutes so that it accurately discovers unknown signals.The OR-CMMF approach outperformed other state-of-the-art open-set recognition methods in comprehensive recognition performance and running time,as demonstrated by simulation experiments on two public datasets RML2016.10a and ORACLE. 展开更多
关键词 manifold mixup open-set recognition synthetic representation unknown signal recognition
在线阅读 下载PDF
Event-triggered control for a class of large-scale nonlinear systems with neutral delays and unknown backlash-like hysteresis
8
作者 Yiyu Feng Weihao Pan +1 位作者 Yanan Qi Xianfu Zhang 《Control Theory and Technology》 2025年第2期253-265,共13页
This paper investigates the problem of dynamic event-triggered control for a class of large-scale nonlinear systems.In particular,both neutral delays and unknown backlash-like hysteresis are considered.This requires t... This paper investigates the problem of dynamic event-triggered control for a class of large-scale nonlinear systems.In particular,both neutral delays and unknown backlash-like hysteresis are considered.This requires to integrate a compensation mechanism into the event-triggered control architecture.To this end,dynamic gain and adaptive control techniques are introduced to address the effects of neutral delays,unknown hysteresis and parameter uncertainties simultaneously.By introducing a non-negative internal dynamic variable,a dynamic event-triggered controller is designed using the hyperbolic tangent function to reduce the communication burden.By means of the Lyapunov–Krasovskii method,it is demonstrated that all signals of the closed-loop system are globally bounded and eventually converge to a tunable bounded region.Moreover,the Zeno behavior is avoided.Finally,a simulation example is presented to verify the validity of the control scheme. 展开更多
关键词 Large-scale nonlinear systems Neutral delays unknown backlash-like hysteresis Event-triggered control
原文传递
Prescribed Performance Control of Nonlinear Systems With Unknown Sign-Switching Virtual Control Coefficients
9
作者 Jin-Zi Yang Jin-Xi Zhang Tianyou Chai 《IEEE/CAA Journal of Automatica Sinica》 2025年第7期1381-1390,共10页
The problem of high-performance tracking controlfor the lower-triangular systems with unknown sign-switchingvirtual control coefficients as well as unmatched disturbances isinvestigated in this paper.Instead of the on... The problem of high-performance tracking controlfor the lower-triangular systems with unknown sign-switchingvirtual control coefficients as well as unmatched disturbances isinvestigated in this paper.Instead of the online estimation algorithm,the sliding mode method and the Nussbaum gain technique,a group of orientation functions are employed to handlethe unknown sign-switching virtual control coefficients.The controllaw is combined with the orientation functions and the barrierfunctions lumped in a recursive manner.It achieves outputtracking with the preassigned rate,overshoot,and accuracy.Incontrast with the existing solutions,it is effective for the nearlymodel-free case,with the requirement for information of neitherthe system nonlinearities nor their bounding functions of theplant,nor the bounds of the disturbances.In addition,our controllerexhibits significant simplicity,without parameter identification,disturbance estimation,function approximation,derivativecalculation,dynamic surfaces,or command filtering.Twosimulation examples are conducted to substantiate the efficacyand advantages of our approach. 展开更多
关键词 High-performance control lower-triangular systems reference tracking unknown sign-switching virtual control coefficients
在线阅读 下载PDF
Observed-based adaptive neural tracking control for nonlinear systems with unknown control directions and input delay
10
作者 DENG Yuxuan WANG Qingling 《Journal of Systems Engineering and Electronics》 2025年第1期269-279,共11页
Enhancing the stability and performance of practical control systems in the presence of nonlinearity,time delay,and uncertainty remains a significant challenge.Particularly,a class of strict-feedback nonlinear uncerta... Enhancing the stability and performance of practical control systems in the presence of nonlinearity,time delay,and uncertainty remains a significant challenge.Particularly,a class of strict-feedback nonlinear uncertain systems characterized by unknown control directions and time-varying input delay lacks comprehensive solutions.In this paper,we propose an observerbased adaptive tracking controller to address this gap.Neural networks are utilized to handle uncertainty,and a unique coordinate transformation is employed to untangle the coupling between input delay and unknown control directions.Subsequently,a new auxiliary signal counters the impact of time-varying input delay,while a Nussbaum function is introduced to solve the problem of unknown control directions.The leverage of an advanced dynamic surface control technique avoids the“complexity explosion”and reduces boundary layer errors.Synthesizing these techniques ensures that all the closed-loop signals are semi-globally uniformly ultimately bounded(SGUUB),and the tracking error converges to a small region around the origin by selecting suitable parameters.Simulation examples are provided to demonstrate the feasibility of the proposed approach. 展开更多
关键词 adaptive neural network dynamic surface control unknown control direction input delay
在线阅读 下载PDF
Squamous cell carcinoma of unknown primary in the pelvis after complete remission following chemoradiotherapy:A case report
11
作者 Anupam K Gupta Harsha Polavarapu 《World Journal of Clinical Cases》 2025年第33期71-75,共5页
BACKGROUND Pelvic squamous cell carcinoma of unknown primary(CUP)is extremely rare,accounting for less than one percent of all CUP cases,and its infrequency has lim-ited the development of standardized diagnostic and ... BACKGROUND Pelvic squamous cell carcinoma of unknown primary(CUP)is extremely rare,accounting for less than one percent of all CUP cases,and its infrequency has lim-ited the development of standardized diagnostic and treatment guidelines.CASE SUMMARY A 77-year-old female with a history of resected lung adenocarcinoma presented with worsening constipation.Imaging revealed a 2.5 cm mass adjacent to the right levator ani muscle.Biopsy confirmed poorly differentiated squamous cell carcinoma,positive for pancytokeratin and p40,and negative for p16,cytokeratin 7,cytokeratin 20,and neuroendocrine markers.No primary lesion was identified despite extensive evaluation.She underwent five cycles of 5-fluorouracil(1000 mg/m^(2) continuous infusion,days 1-4)and mitomycin-C(10 mg/m^(2) on day 1)with concurrent pelvic radiotherapy(50.4 Gy in 28 fractions).Follow-up imaging demonstrated complete remission sustained for 12 months.Electrocorticography performance status improved from 2 at diagnosis to 1 during follow-up.CONCLUSION This case highlights the potential role of chemoradiotherapy in managing pelvic squamous cell CUP,achieving durable remission in selected patients. 展开更多
关键词 Squamous cell carcinoma Cancer of unknown primary Pelvic malignancy CHEMORADIOTHERAPY Human papillomavirus negative p40 positive Pelvic floor tumor Case report
暂未订购
Non-line-of-sight target localization in unknown L-shaped corridor based UWB MIMO radar
12
作者 JIA Chao SONG Caiping +4 位作者 WANG Lingyu CUI Guolong GUO Shisheng GU Jie JIA Yong 《Journal of Systems Engineering and Electronics》 2025年第3期681-693,共13页
Most of the existing non-line-of-sight(NLOS)localization methods depend on the layout information of the scene which is difficult to be obtained in advance in the practical application scenarios.To solve the problem,a... Most of the existing non-line-of-sight(NLOS)localization methods depend on the layout information of the scene which is difficult to be obtained in advance in the practical application scenarios.To solve the problem,an NLOS target localization method in unknown L-shaped corridor based ultra-wideband(UWB)multiple-input multiple-output(MIMO)radar is proposed in this paper.Firstly,the multipath propagation model of Lshaped corridor is established.Then,the localization process is analyzed by the propagation characteristics of diffraction and reflection.Specifically,two different back-projection imaging processes are performed on the radar echo,and the positions of focus regions in the two images are extracted to generate candidate targets.Furthermore,the distances of propagation paths corresponding to each candidate target are calculated,and then the similarity between each candidate target and the target is evaluated by employing two matching factors.The locations of the targets and the width of the corridor are determined based on the matching rules.Finally,two experiments are carried out to demonstrate that the method can effectively obtain the target positions and unknown scene information even when partial paths are lost. 展开更多
关键词 non-line-of-sight(NLOS)localization unknown Lshaped corridor multiple-input multiple-output(MIMO)radar back-projection imaging multipath propagation
在线阅读 下载PDF
Adaptive Fault-Tolerant Control for Unknown Affine Nonlinear Systems Based on Self-Organizing RBF Neural Network
13
作者 Ran Chen Donghua Zhou Li Sheng 《IEEE/CAA Journal of Automatica Sinica》 2025年第9期1788-1800,共13页
This article presents an adaptive fault-tolerant tracking control strategy for unknown affine nonlinear systems subject to actuator faults and external disturbances.To address the hyperparameter initialization challen... This article presents an adaptive fault-tolerant tracking control strategy for unknown affine nonlinear systems subject to actuator faults and external disturbances.To address the hyperparameter initialization challenges inherent in conventional neural network training,an improved self-organizing radial basis function neural network(SRBFNN)with an input-dependent variable structure is developed.Furthermore,a novel selforganizing RBFNN-based observer is introduced to estimate system states across all dimensions.Leveraging the reconstructed states,the proposed adaptive controller effectively compensates for all uncertainties,including estimation errors in the observer,ensuring accurate state tracking with reduced control effort.The uniform ultimate boundedness of all closed-loop signals and tracking errors is rigorously established via Lyapunov stability analysis.Finally,simulations on two different nonlinear systems comprehensively validate the effectiveness and superiority of the proposed control approach. 展开更多
关键词 Adaptive tracking control fault-tolerant control self-organizing radial basis function neural network(SRBFNN) unknown affine nonlinear system
在线阅读 下载PDF
Case Study and Literature Review on Diagnosis and Treatment of Advanced Metastasis of Tumor with Unknown Primary Origin
14
作者 Leting Dong Shi Yue +2 位作者 Yungui Gao Yaqi Yin Shengli Huang 《Proceedings of Anticancer Research》 2025年第4期114-120,共7页
Primary of Unknown Origin Cancer(CUP)is a metastatic tumor whose origin remains undetermined.The reason for this ambiguity in identifying the primary site remains unclear,possibly due to the tumor being too small or g... Primary of Unknown Origin Cancer(CUP)is a metastatic tumor whose origin remains undetermined.The reason for this ambiguity in identifying the primary site remains unclear,possibly due to the tumor being too small or growing too slowly,or because the immune system has destroyed the tiny primary lesion.Most CUP patients receive only localized treatment or empirical systemic chemotherapy,leading to poor prognosis and shorter average overall survival.There is currently insufficient evidence-based medical support for the diagnosis and treatment of CUP.This study retrospectively analyzed clinical characteristics,diagnostic methods,treatment approaches,and prognostic outcomes of newly diagnosed CUP patients treated in our department.The findings aim to provide clinical guidance for diagnosis and treatment of CUP,with the goal of reducing diagnostic delays and improving patient outcomes. 展开更多
关键词 Primary of unknown Origin Cancer Case report Literature analysis diagnosis Cervical lymph nodes Online publication:August 6 2025
暂未订购
Data-Driven Iterative Learning Consensus Tracking Based on Robust Neural Models for Unknown Heterogeneous Nonlinear Multiagent Systems With Input Constraints
15
作者 Chong Zhang Yunfeng Hu +2 位作者 TingTing Wang Xun Gong Hong Chen 《IEEE/CAA Journal of Automatica Sinica》 2025年第10期2153-2155,共3页
Dear Editor,Aiming at the consensus tracking problem of a class of unknown heterogeneous nonlinear multiagent systems(MASs)with input constraints,a novel data-driven iterative learning consensus control(ILCC)protocol ... Dear Editor,Aiming at the consensus tracking problem of a class of unknown heterogeneous nonlinear multiagent systems(MASs)with input constraints,a novel data-driven iterative learning consensus control(ILCC)protocol based on zeroing neural networks(ZNNs)is proposed.First,a dynamic linearization data model(DLDM)is acquired via dynamic linearization technology(DLT). 展开更多
关键词 dynamic linearization data model dldm consensus tracking problem input constraints consensus tracking unknown heterogeneous nonlinear multiagent systems robust neural models data driven iterative learning zeroing neural networks znns
在线阅读 下载PDF
Global Stabilization via Adaptive Event-Triggered Output Feedback for Nonlinear Systems With Unknown Measurement Sensitivity
16
作者 Yupin Wang Hui Li 《IEEE/CAA Journal of Automatica Sinica》 2025年第4期833-835,共3页
Dear Editor,This letter investigates global stabilization of uncertain nonlinear systems via adaptive event-triggered output feedback.Uncertainties lie in both system nonlinearities and measurement sensitivity.To this... Dear Editor,This letter investigates global stabilization of uncertain nonlinear systems via adaptive event-triggered output feedback.Uncertainties lie in both system nonlinearities and measurement sensitivity.To this end,a dynamic high gain is introduced to cope with the influence of large uncertainties,the unknown measurement sensitivity and the execution error,while a time-varying threshold event-triggering mechanism is constructed to effectively exclude the Zeno phenomenon.As such,the adaptive event-triggered control ensures globally bounded and convergent of system states.The design method is demonstrated using a controlled pendulum example. 展开更多
关键词 nonlinear systems global stabilization dynamic high gain zeno phenomenonas unknown measurement sensitivity adaptive event triggered output feedback time varying threshold event triggering mechanism
在线阅读 下载PDF
Production of unknown neutron-deficient isotopes with Z=99-106 in multinucleon transfer reaction^(124)Xe+^(249)Cf
17
作者 Na Tang Si-Ying Ma +2 位作者 Rong An Jing-Jing Li Feng-Shou Zhang 《Nuclear Science and Techniques》 2025年第3期95-104,共10页
The dinuclear system approach,coupled with the statistical decay model GEMINI++,was used to investigate multinucleon transfer reactions.Experimental production cross-sections in the reaction^(129)Xe+^(248)Cm were repr... The dinuclear system approach,coupled with the statistical decay model GEMINI++,was used to investigate multinucleon transfer reactions.Experimental production cross-sections in the reaction^(129)Xe+^(248)Cm were reproduced to assess the reliability of these theoretical models.The production of neutron-deficient transcalifornium nuclei with Z=99-106 was examined in multinucleon transfer reactions,including^(124)Xe+^(248)Cm,^(124)Xe+^(249)Cf,and^(129)Xe+^(249)Cf.Both the driving potential and the neutron-to-proton equilibration ratio were found to dominate the nucleon transfer process.The reaction^(124)Xe+^(249)Cf is proposed as a promising projectile-target combination for producing neutron-deficient isotopes with Z=99-106,with the optimal incident energy identified as E_(c.m.)=533.64 MeV.Production cross-sections of 25 unknown neutron-deficient trancalifornium isotopes with cross-sections greater than 1 pb were predicted. 展开更多
关键词 Multinucleon transfer reaction Dinuclear system unknown neutron-deficient isotopes with Z=99-106
在线阅读 下载PDF
基于新型贪心-D^(*)算法的无人机全覆盖路径规划
18
作者 周映江 谢明慧 +2 位作者 蒋国平 徐丰羽 高辉 《南京邮电大学学报(自然科学版)》 北大核心 2026年第1期111-123,共13页
针对动态未知环境中全覆盖路径规划面临的路径冗余率高和环境适应性差等难题,提出一种基于新型贪心-D^(*)算法(Novel Greedy-D^(*)Algorithm,NG-D^(*))的无人机全覆盖路径规划。首先,构建动态增量式环境建模系统,实现障碍物分布实时更... 针对动态未知环境中全覆盖路径规划面临的路径冗余率高和环境适应性差等难题,提出一种基于新型贪心-D^(*)算法(Novel Greedy-D^(*)Algorithm,NG-D^(*))的无人机全覆盖路径规划。首先,构建动态增量式环境建模系统,实现障碍物分布实时更新与矩阵化栅格状态精准映射,增强系统环境感知能力。其次,设计最小值优先三元组贪心决策函数,通过评估曼哈顿距离、横向优先级与纵向优先级,生成结构化有序覆盖路径。最后,引入关键节点导向D^(*)逃离算法,在检测到局部死区时高效规划平滑脱离路径。实验结果表明,相较于传统方法,NG-D^(*)算法在保持覆盖完整性的前提下,将路径冗余率降低至3.0%以下。 展开更多
关键词 D^(*)算法 贪心策略 全覆盖路径规划 未知环境 无人机
在线阅读 下载PDF
基于安全强化学习的多无人机编队与避障控制
19
作者 陈众楷 周晗 +3 位作者 孙懿豪 闫超 相晓嘉 陈谋 《中国科学:信息科学》 北大核心 2026年第2期409-424,共16页
多无人机编队作为无人机技术的重要发展方向,展现出强大的应用潜力和研究价值.近年来,基于深度强化学习算法训练多无人机编队控制策略得到了愈发广泛的关注.然而,在编队策略学习中,环境的未知性和传感器误差等因素可能导致无人机采取不... 多无人机编队作为无人机技术的重要发展方向,展现出强大的应用潜力和研究价值.近年来,基于深度强化学习算法训练多无人机编队控制策略得到了愈发广泛的关注.然而,在编队策略学习中,环境的未知性和传感器误差等因素可能导致无人机采取不安全或不合理的动作,影响策略学习的安全性和稳定性.针对这一问题,提出了一种基于安全强化学习的多无人机编队与避障控制方法.首先,考虑环境扰动、传感器误差等因素的影响,基于部分观测马尔可夫(Markov)决策过程建立多无人机编队控制模型.在此基础上,设计最大池化多智能体深度确定性策略梯度算法,训练编队控制的标称策略;同时构建基于控制障碍函数的安全过滤器,用于修正标称策略输出的不安全动作,确保编队飞行过程的安全性.最后,通过数值仿真和实物飞行实验,验证了所提多无人机编队避障方法的安全性和有效性. 展开更多
关键词 安全强化学习 多无人机系统 编队控制 控制障碍函数 未知环境
原文传递
广义未知扰动下多模型最小上限滤波
20
作者 秦月梅 张荣华 +1 位作者 杨衍波 潘泉 《北京航空航天大学学报》 北大核心 2026年第1期129-139,共11页
针对现有机动目标跟踪算法在广义未知扰动下跟踪峰值误差过大的问题,提出一种多模型最小上限滤波(MMUBF)算法。在多模型框架下利用最小上限滤波对不同模式下状态进行递推估计,根据滤波结果及模型后验概率估计加权在线辨识扰动分量,将其... 针对现有机动目标跟踪算法在广义未知扰动下跟踪峰值误差过大的问题,提出一种多模型最小上限滤波(MMUBF)算法。在多模型框架下利用最小上限滤波对不同模式下状态进行递推估计,根据滤波结果及模型后验概率估计加权在线辨识扰动分量,将其引入各模式下似然概率计算以减弱其对模型概率更新的影响。同时,为进一步提升模式匹配精度,利用修正因子自适应调整马尔可夫转移概率矩阵。此外,通过计算每个步骤的浮点运算数量,分析所提算法的计算复杂度。具有时变未知扰动的机动目标跟踪仿真结果表明:相比于现有交互式多模型滤波、自适应交互式多模型滤波、灰狼优化算法改进后的自适应交互式多模型滤波和基于单模型的最小上限滤波算法,所提算法在不同量测噪声、过程噪声、调整系数及概率修正阈值水平下皆具有更小峰值误差和更高估计精度。 展开更多
关键词 最小上限滤波 广义未知扰动 多模型 修正因子 转移概率矩阵
原文传递
上一页 1 2 162 下一页 到第
使用帮助 返回顶部