BACKGROUND Electromagnetic navigational bronchoscopy(ENB)is an emerging diagnostic tool that enables practitioners to biopsy peripheral lung tissues that were previously only accessible under computed tomography(CT)gu...BACKGROUND Electromagnetic navigational bronchoscopy(ENB)is an emerging diagnostic tool that enables practitioners to biopsy peripheral lung tissues that were previously only accessible under computed tomography(CT)guidance.However,few studies have investigated ENB use in children.Here,we report a case of a 10-yearold girl with peripheral lung lesions who complained of a 7-d persistent fever.She was diagnosed with Streptococcus parasanguinis infection based on findings obtained using ENB-guided transbronchial lung biopsy(TBLB).CASE SUMMARY A 10-year-old girl presented with constitutional symptoms of cough and fever of 7 days’duration.Chest CT scans detected peripheral lung lesions and no endobronchial lesions.TBLB performed under the guidance of an ENB Lungpro navigation system was safe,well-tolerated,and effective for biopsying peripheral lung lesions.Examination of biopsied samples indicated the patient had a pulmonary Streptococcus parasanguinis infection,which was treated with antibiotics instead of more invasive treatment interventions.The patient’s symptoms resolved after she received a 3-wk course of oral linezolid.Comparisons of pretreatment and post-treatment CT scans revealed absorption of some lung lesions within 7 mo of hospital discharge.CONCLUSION ENB-guided TBLB biopsying of peripheral lung lesions in this child is a safe,well-tolerated,and effective alternative to conventional interventions.展开更多
By use of bathymetric chart, recent change of the riverbed in the North Passage of the Yangtze Estuary has been studied in this paper. The main channel of the upper, middle and lower （section） in the North Passage h...By use of bathymetric chart, recent change of the riverbed in the North Passage of the Yangtze Estuary has been studied in this paper. The main channel of the upper, middle and lower （section） in the North Passage has been successively eroded and its groin field significantly deposited. At the same time, sediment has been deposited on the entrance region. Erosion and deposition had responded rapidly to the construction of the regulation engineering. There was about one year duration of lagging between erosion in the deep channel and the construction of the regulation engineering. The siltation lag of time in the groin field varied with the initial depth, but the average deposited thickness was about 0.5 m per year. Volumetric analysis demonstrates that there is a increasing trend of siltation in the North Passage after 2002, because of the difference in duration and quantity between erosion in the deep channel and deposition in the groin field. The water volume of the North Passage was reduced by =9% （280 million m^3） between 2002 and 2006. Sediment budget reveals that the main sediment deposited in the North Passage takes its source from the river and the ocean. The decreasing water volume was attributable to shoaling in the groin field. Its triggering factors for increased sedimentation are the navigational improvements（jetties and groins） after 1998, which altered the passage boundary and destroyed the equilibrium state on the average ebb and flood sediment fluxes. The establishment of a stable estuary is attributed to a reduction in depth of the groin field. The forecast on the sediment deposition quantity and continuous infilling time in the groin system is about 325 × 10^6m^3 and 6 - 7 years, respectively.展开更多
Purpose: Professional high speed sea navigational procedures are based on turn points, courses, dangers and steering cues in the environment. Since navigational aids have become less expensive and due to the fact that...Purpose: Professional high speed sea navigational procedures are based on turn points, courses, dangers and steering cues in the environment. Since navigational aids have become less expensive and due to the fact that electronic sea charts can be integrated with both radar and transponder information, it may be assumed that traditional navigation by using paper based charts and radar will play a less significant role in the future, especially among less experienced navigators. Possible navigational differences between experienced and non-experienced boat drivers is thus of interest with regards to their use of navigational aids. It may be assumed that less experienced navigators rely too much on the information given by the electronic sea chart, despite the fact that it is based on GPS information that can be questioned, especially in littoral waters close to land. Method: This eye tracking study investigates gaze behaviour from 16 ex perienced and novice boat drivers during high speed navigation at sea. Results: The results show that the novice drivers look at objects that are close to themselves, like instrumentation, while the experienced look more at objects far away from the boat. This is in accordance with previous research on car drivers. Further, novice boat drivers used the electronic navigational aids to a larger extent than the experienced, especially during high speed conditions. The experienced drivers focused much of their attention on objects outside the boat. Conclusions: The findings verify that novice boat drivers tend to rely on electronic navigational aids. Experienced drivers presumably use the navigational aids to verify what they have observed in the surrounding environment and further use the paper based sea chart to a larger extent than the novice drivers.展开更多
Due to the flammability and explosive nature of liquefied natural gas(LNG),an extremely strict process is followed for the transporta-tion of LNG carriers in China.Particularly,no LNG carriers are operating in inland ...Due to the flammability and explosive nature of liquefied natural gas(LNG),an extremely strict process is followed for the transporta-tion of LNG carriers in China.Particularly,no LNG carriers are operating in inland rivers within the country.Therefore,to ensure the future navigation safety of LNG carriers entering the Yangtze River,the risk sources of LNG carriers’navigation safety must be identi-fied and evaluated.Based on the Delphi and expert experience method,this paper analyses and discusses the navigation risk factors of LNG carriers in the lower reaches of the Yangtze River from four aspects(human,ship,environment and management),identifies 12 risk indicators affecting the navigation of LNG carriers and establishes a risk evaluation index system.Further,an entropy weight fuzzy model is utilized to reduce the influence of subjective judgement on the index weight as well as to conduct a segmented and overall evaluation of LNG navigation risks in the Baimaosha Channel.Finally,the cloud model is applied to validate the consistent feasibility of the entropy weight fuzzy model.The research results indicate that the method provides effective technical support for further study on the navigation security of LNG carriers in inland rivers.展开更多
An M6.2 earthquake struck Jishishan County,Gansu,on December 18,2023,with its epicenter located in the arc-shaped tectonic belt formed by the Lajishan-Jishishan Fault.Continuous high-rate global navigational satellite...An M6.2 earthquake struck Jishishan County,Gansu,on December 18,2023,with its epicenter located in the arc-shaped tectonic belt formed by the Lajishan-Jishishan Fault.Continuous high-rate global navigational satellite system(GNSS)data were utilized to simulate real-time data resolution,enabling the rapid determination of coseismic static and dynamic deformation caused by the earthquake and the estimation of empirical magnitude.Far-field body waves served as constraints for the source rupture process,facilitating the analysis of potential seismogenic fault structures.GNSS stations within 30 km of the epicenter exhibited significant coseismic responses:horizontal peak displacement and velocity reached approximately 6.3 cm and 6.1 cm/s,respectively.Additionally,quasi-real-time differential positioning and post-event precise point positioning results were consistent throughout the source process.Vertical velocity,calculated via epoch-by-epoch differential velocity determination,showed clear coseismic signals,with peak values increasing to 2.6 cm/s.The empirical magnitude,based on displacement,was 5.99,while the magnitude derived from the velocity waveform amplitude was 6.05,both consistent with the moment magnitude.The dynamic displacement distribution preliminarily suggests directional effects of northward rupture propagation,aligning with subsequent aftershock occurrences.Finite fault inversion results,based on the two nodal planes of the focal mechanism,indicate that asperity ruptures concentrated at the hypocenter played a major role.These ruptures propagated from the hypocenter to shallow regions and northward,lasting approximately 10 s.Although the coseismic deformation determined by sparse high-rate GNSS cannot constrain the specific fault dip angle,the relationship between rupture propagation direction from the seismic source model and aftershock distribution suggests a northeast-dipping fault.Moreover,seismic source models representing single faults as geometric structures can only simulate permanent formations.In contrast,the conjugate fault model,which aligns with aftershock distributions,more accurately explains high-rate GNSS displacement waveforms.Considering both regional tectonics and geological survey results,the seismogenic fault is believed to be a local northeast-dipping blind thrust fault.Northward rupture propagation may have caused the movement of conjugate faults.This study is an effective case of using high-rate GNSS for rapid earthquake response,providing a reference basis for understanding the seismic activity patterns and earthquake disaster prevention in the region.展开更多
This paper proposes a safety evaluation model of inland waterway ship navigation based on the fuzzy theory and evidential reasoning(ER)approach.The proposed model is a three-level hierarchical system consisting of 18 ...This paper proposes a safety evaluation model of inland waterway ship navigation based on the fuzzy theory and evidential reasoning(ER)approach.The proposed model is a three-level hierarchical system consisting of 18 indicators that are identified and determined through literature review and expert surveys.By using fuzzy theory,the factors of the index level are converted into belief distributions,and the information of indicators within each level is merged by using the ER approach so that the evaluation of the ship’s navigation safety can be realized.This model can deal with multi-source information and both qualitative and quantitative indicators in an integrated framework.Some case studies on the safety status of ships navigating in the middle reaches of the Yangtze River during dry season are conducted to validate the feasibility and practicability of the proposed model.The results show that the risk levels obtained from the proposed model are consistent with the real-life situation to a large extent.The novel model proposed in this study provides a useful reference for maritime safety management and will help managers and decision-makers in the risk prevention and early warning of inland waterway transportation accidents.展开更多
Background and Objective Electromagnetic navigation technology has demonstrated significant potential in enhancing the accuracy and safety of neurosurgical procedures.However,traditional electromagnetic navigation sys...Background and Objective Electromagnetic navigation technology has demonstrated significant potential in enhancing the accuracy and safety of neurosurgical procedures.However,traditional electromagnetic navigation systems face challenges such as high equipment costs,complex operation,bulky size,and insufficient anti-interference performance.To address these limitations,our study developed and validated a novel portable electromagnetic neuronavigation system designed to improve the precision,accessibility,and clinical applicability of electromagnetic navigation technology in cranial surgery.Methods The software and hardware architecture of a portable neural magnetic navigation system was designed.The key technologies of the system were analysed,including electromagnetic positioning algorithms,miniaturized sensor design,optimization of electromagnetic positioning and navigation algorithms,anti-interference signal processing methods,and fast three-dimensional reconstruction algorithms.A prototype was developed,and its accuracy was tested.Finally,a preliminary clinical application evaluation was conducted.Results This study successfully developed a comprehensive portable electromagnetic neuronavigation system capable of achieving preoperative planning,intraoperative real-time positioning and navigation,and postoperative evaluation of navigation outcomes.Through rigorous collaborative testing of the system’s software and hardware,the accuracy of electromagnetic neuronavigation has been validated to meet clinical requirements.Conclusions This study developed a portable neuroelectromagnetic navigation system and validated its effectiveness and safety through rigorous model testing and preliminary clinical applications.The system is characterized by its compact size,high precision,excellent portability,and user-friendly operation,making it highly valuable for promoting navigation technology and advancing the precision and minimally invasive nature of neurosurgical procedures.展开更多
Nonlinear variations in the coordinate time series of global navigation satellite system(GNSS) reference stations are strongly correlated with surface displacements caused by environmental loading effects,including at...Nonlinear variations in the coordinate time series of global navigation satellite system(GNSS) reference stations are strongly correlated with surface displacements caused by environmental loading effects,including atmospheric, hydrological, and nontidal ocean loading. Continuous improvements in the accuracy of surface mass loading products, performance of Earth models, and precise data-processing technologies have significantly advanced research on the effects of environmental loading on nonlinear variations in GNSS coordinate time series. However, owing to theoretical limitations, the lack of high spatiotemporal resolution surface mass observations, and the coupling of GNSS technology-related systematic errors, environmental loading and nonlinear GNSS reference station displacements remain inconsistent. The applicability and capability of these loading products across different regions also require further evaluation. This paper outlines methods for modeling environmental loading, surface mass loading products, and service organizations. In addition, it summarizes recent advances in applying environmental loading to address nonlinear variations in global and regional GNSS coordinate time series. Moreover, the scientific questions of existing studies are summarized, and insights into future research directions are provided. The complex nonlinear motion of reference stations is a major factor limiting the accuracy of the current terrestrial reference frame. Further refining the environmental load modeling method, establishing a surface mass distribution model with high spatiotemporal resolution and reliability, exploring other environmental load factors such as ice sheet and artificial mass-change effects, and developing an optimal data-processing model and strategy for reprocessing global reference station data consistently could contribute to the development of a millimeter-level nonlinear motion model for GNSS reference stations with actual physical significance and provide theoretical support for establishing a terrestrial reference frame with 1 mm accuracy by 2050.展开更多
Terrain Aided Navigation(TAN)technology has become increasingly important due to its effectiveness in environments where Global Positioning System(GPS)is unavailable.In recent years,TAN systems have been extensively r...Terrain Aided Navigation(TAN)technology has become increasingly important due to its effectiveness in environments where Global Positioning System(GPS)is unavailable.In recent years,TAN systems have been extensively researched for both aerial and underwater navigation applications.However,many TAN systems that rely on recursive Unmanned Aerial Vehicle(UAV)position estimation methods,such as Extended Kalman Filters(EKF),often face challenges with divergence and instability,particularly in highly non-linear systems.To address these issues,this paper proposes and investigates a hybrid two-stage TAN positioning system for UAVs that utilizes Particle Filter.To enhance the system’s robustness against uncertainties caused by noise and to estimate additional system states,a Fuzzy Particle Filter(FPF)is employed in the first stage.This approach introduces a novel terrain composite feature that enables a fuzzy expert system to analyze terrain non-linearities and dynamically adjust the number of particles in real-time.This design allows the UAV to be efficiently localized in GPS-denied environments while also reducing the computational complexity of the particle filter in real-time applications.In the second stage,an Error State Kalman Filter(ESKF)is implemented to estimate the UAV’s altitude.The ESKF is chosen over the conventional EKF method because it is more suitable for non-linear systems.Simulation results demonstrate that the proposed fuzzy-based terrain composite method achieves high positional accuracy while reducing computational time and memory usage.展开更多
Fluorescence imaging in the second near-infrared window(NIR-II,900-1880 nm)offers high signalto-background ratio(SBR),enhanced definition,and superior tissue penetration,making it ideal for real-time surgical navigati...Fluorescence imaging in the second near-infrared window(NIR-II,900-1880 nm)offers high signalto-background ratio(SBR),enhanced definition,and superior tissue penetration,making it ideal for real-time surgical navigation.However,with single-channel imaging,surgeons must frequently switch between the surgi⁃cal field and the NIR-II images on the monitor.To address this,a coaxial dual-channel imaging system that com⁃bines visible light and 1100 nm longpass(1100LP)fluorescence was developed.The system features a custom⁃ized coaxial dual-channel lens with optimized distortion,achieving precise alignment with an error of less than±0.15 mm.Additionally,the shared focusing mechanism simplifies operation.Using FDA-approved indocya⁃nine green(ICG),the system was successfully applied in dual-channel guided rat lymph node excision,and blood supply assessment of reconstructed human flap.This approach enhances surgical precision,improves opera⁃tional efficiency,and provides a valuable reference for further clinical translation of NIR-II fluorescence imaging.展开更多
With the increase of international trade activities and the gradual melting of the polar ice cap,the importance of the Arctic route for marine transportation has been emphasized.Prediction of the polar navigation wind...With the increase of international trade activities and the gradual melting of the polar ice cap,the importance of the Arctic route for marine transportation has been emphasized.Prediction of the polar navigation window period is crucial for navigating in the Arctic route,which is of great significance to the selection of the route and the optimization of navigation.This paper introduces the establishment of a risk index system,determination of risk index weight,establishment of a risk evaluation model,and prediction algorithm for the window period.In addition,data sources of both environmental factors and ship factors are introducted,and their shortcomings are analyzed,followed by introduction of various methods involved in window prediction and analysis of their advantages and disadvantages.The quantitative risk evaluation and window period algorithm can provide a reference for the research of polar navigation window period prediction.展开更多
1. Introduction Celestial navigation is a kind of navigation with a long history.With the increasing demand for intelligent autonomy and antielectromagnetic interference in spacecraft, celestial navigation has become ...1. Introduction Celestial navigation is a kind of navigation with a long history.With the increasing demand for intelligent autonomy and antielectromagnetic interference in spacecraft, celestial navigation has become one of the current research hotspots in spacecraft autonomous navigation. Spacecraft face complex electromagnetic interference in orbit. The time-varying, non-Gaussian interference from internal devices and external environment can lead to measurement distortion.展开更多
In order to address the challenges encountered in visual navigation for asteroid landing using traditional point features,such as significant recognition and extraction errors,low computational efficiency,and limited ...In order to address the challenges encountered in visual navigation for asteroid landing using traditional point features,such as significant recognition and extraction errors,low computational efficiency,and limited navigation accuracy,a novel approach for multi-type fusion visual navigation is proposed.This method aims to overcome the limitations of single-type features and enhance navigation accuracy.Analytical criteria for selecting multi-type features are introduced,which simultaneously improve computational efficiency and system navigation accuracy.Concerning pose estimation,both absolute and relative pose estimation methods based on multi-type feature fusion are proposed,and multi-type feature normalization is established,which significantly improves system navigation accuracy and lays the groundwork for flexible application of joint absolute-relative estimation.The feasibility and effectiveness of the proposed method are validated through simulation experiments through 4769 Castalia.展开更多
As the core information infrastructure of modern information warfare,the offensive and defensive confrontations of satellite navigation systems have given rise to navigation warfare,which focuses on seizing control of...As the core information infrastructure of modern information warfare,the offensive and defensive confrontations of satellite navigation systems have given rise to navigation warfare,which focuses on seizing control of navigation resources.Based on the space segment,control segment,and user segment of satellite navigation systems,this paper systematically constructs an offensive-defensive technology system for navigation warfare,and deeply analyzes core measures such as signal enhancement and suppression,autonomous navigation and link jamming,anti-jamming reception,and integrated navigation.It extracts key technologies including adaptive nulling antennas,joint filtering,and multi-dimensional combined jamming,and discusses the technical effectiveness of these technologies by incorporating relevant cases.The advantages of navigation warfare stem from multi-segment coordination and technological inte-gration.In the future,the development directions of navigation warfare will focus on three aspects:enhancing satellite capabilities,tackling core technical challenges,and building a multi-dimensional system.展开更多
This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification metho...This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification methodology for practical implementation of vision-based navigation technology on the microsatellite platform.Firstly,a low power consumption,light weight,and high performance vision-based relative navigation optical sensor is designed.Subsequently,a set of ground verification system is designed for the hardware-in-the-loop testing of the vision-based relative navigation systems.Finally,the designed vision-based relative navigation optical sensor and the proposed angles-only navigation algorithms are tested on the ground verification system.The results verify that the optical simulator after geometrical calibration can meet the requirements of the hardware-in-the-loop testing of vision-based relative navigation systems.Based on experimental results,the relative position accuracy of the angles-only navigation filter at terminal time is increased by 25.5%,and the relative speed accuracy is increased by 31.3% compared with those of optical simulator before geometrical calibration.展开更多
The Global Navigation Satellite System(GNSS)has been widely adopted in numerous fields,including intelligent transportation,remote sensing,and aeronautical and astronautical engineering.As new navigation approaches,te...The Global Navigation Satellite System(GNSS)has been widely adopted in numerous fields,including intelligent transportation,remote sensing,and aeronautical and astronautical engineering.As new navigation approaches,technologies,and applications continue to emerge,they attract significant global attention.Ensuring reliable positioning solutions with high accuracy,strong anti-interference capabilities,high availability and low integrity risks has become increasingly critical.展开更多
Objective:To observe the guiding role of image navigation technology in the treatment of patients with tuberculosis.Methods:A total of 188 patients with multidrug-resistant tuberculosis(MDR-TB)and rifampin-resistant t...Objective:To observe the guiding role of image navigation technology in the treatment of patients with tuberculosis.Methods:A total of 188 patients with multidrug-resistant tuberculosis(MDR-TB)and rifampin-resistant tuberculosis(RR-TB)who were hospitalized in the hospital from September 2023 to September 2024 were included.After random equal division,94 patients were included in the control group and received systemic anti-tuberculosis chemotherapy;94 patients were included in the treatment group.Based on systemic anti-tuberculosis treatment,digital subtraction angiography(DSA)technology was used to inject targeted drugs into the bronchial lumen through bronchoscopy to complete anti-tuberculosis treatment.The changes in sputum bacteria and imaging were observed in the two groups.Results:The sputum negative conversion rate in the treatment group was significantly higher than that in the control group(86.2%;70.2%)(u=2.74,P<0.01).The absorption rate of CT imaging lesions(significant absorption)was significantly higher than that of the control group(83.0%;50%)(u=2.45,P<0.05).The closure rate of chest CT cavities was significantly higher than that of the control group(74.2%;39.1%)(u=2.20,P<0.05).During the treatment process,the improvement of clinical symptoms was significantly higher than that of the control group,and the difference was statistically significant.There was no statistically significant difference in the incidence of adverse reactions between the two groups(x^(2)=0.434,P>0.05).Conclusion:Based on DSA,targeted drug infusion within the bronchoscope can significantly improve the efficacy of the disease,with mild adverse reactions that patients can tolerate.It is worthy of promotion and application.展开更多
In multiple Unmanned Aerial Vehicles(UAV)systems,achieving efficient navigation is essential for executing complex tasks and enhancing autonomy.Traditional navigation methods depend on predefined control strategies an...In multiple Unmanned Aerial Vehicles(UAV)systems,achieving efficient navigation is essential for executing complex tasks and enhancing autonomy.Traditional navigation methods depend on predefined control strategies and trajectory planning and often perform poorly in complex environments.To improve the UAV-environment interaction efficiency,this study proposes a multi-UAV integrated navigation algorithm based on Deep Reinforcement Learning(DRL).This algorithm integrates the Inertial Navigation System(INS),Global Navigation Satellite System(GNSS),and Visual Navigation System(VNS)for comprehensive information fusion.Specifically,an improved multi-UAV integrated navigation algorithm called Information Fusion with MultiAgent Deep Deterministic Policy Gradient(IF-MADDPG)was developed.This algorithm enables UAVs to learn collaboratively and optimize their flight trajectories in real time.Through simulations and experiments,test scenarios in GNSS-denied environments were constructed to evaluate the effectiveness of the algorithm.The experimental results demonstrate that the IF-MADDPG algorithm significantly enhances the collaborative navigation capabilities of multiple UAVs in formation maintenance and GNSS-denied environments.Additionally,it has advantages in terms of mission completion time.This study provides a novel approach for efficient collaboration in multi-UAV systems,which significantly improves the robustness and adaptability of navigation systems.展开更多
Since its inception in the 1960s,light detection and ranging(LiDAR)technology has demonstrated great potential in various fields such as autonomous driving,robot navigation,and environmental monitoring due to its high...Since its inception in the 1960s,light detection and ranging(LiDAR)technology has demonstrated great potential in various fields such as autonomous driving,robot navigation,and environmental monitoring due to its high precision,high resolution,and strong anti-interference capability.This paper reviews the development history,technical principles,application fields,and future development trends of LiDAR technology.It introduces the technical applications of LiDAR technology in autonomous driving,robot navigation,and environmental monitoring,and explores the development direction of SLAM algorithms in multi-sensor fusion and real-time map construction,providing a reference basis for the development and research of LiDAR.展开更多
Robot navigation in complex crowd service scenarios,such as medical logistics and commercial guidance,requires a dynamic balance between safety and efficiency,while the traditional fixed reward mechanism lacks environ...Robot navigation in complex crowd service scenarios,such as medical logistics and commercial guidance,requires a dynamic balance between safety and efficiency,while the traditional fixed reward mechanism lacks environmental adaptability and struggles to adapt to the variability of crowd density and pedestrian motion patterns.This paper proposes a navigation method that integrates spatiotemporal risk field modeling and adaptive reward optimization,aiming to improve the robot’s decision-making ability in diverse crowd scenarios through dynamic risk assessment and nonlinear weight adjustment.We construct a spatiotemporal risk field model based on a Gaussian kernel function by combining crowd density,relative distance,andmotion speed to quantify environmental complexity and realize crowd-density-sensitive risk assessment dynamically.We apply an exponential decay function to reward design to address the linear conflict problem of fixed weights in multi-objective optimization.We adaptively adjust weight allocation between safety constraints and navigation efficiency based on real-time risk values,prioritizing safety in highly dense areas and navigation efficiency in sparse areas.Experimental results show that our method improves the navigation success rate by 9.0%over state-of-the-art models in high-density scenarios,with a 10.7%reduction in intrusion time ratio.Simulation comparisons validate the risk field model’s ability to capture risk superposition effects in dense scenarios and the suppression of near-field dangerous behaviors by the exponential decay mechanism.Our parametric optimization paradigm establishes an explicit mapping between navigation objectives and risk parameters through rigorous mathematical formalization,providing an interpretable approach for safe deployment of service robots in dynamic environments.展开更多
基金Supported by The Natural Science Foundation of Jilin Province,No.20200201475JC.
文摘BACKGROUND Electromagnetic navigational bronchoscopy(ENB)is an emerging diagnostic tool that enables practitioners to biopsy peripheral lung tissues that were previously only accessible under computed tomography(CT)guidance.However,few studies have investigated ENB use in children.Here,we report a case of a 10-yearold girl with peripheral lung lesions who complained of a 7-d persistent fever.She was diagnosed with Streptococcus parasanguinis infection based on findings obtained using ENB-guided transbronchial lung biopsy(TBLB).CASE SUMMARY A 10-year-old girl presented with constitutional symptoms of cough and fever of 7 days’duration.Chest CT scans detected peripheral lung lesions and no endobronchial lesions.TBLB performed under the guidance of an ENB Lungpro navigation system was safe,well-tolerated,and effective for biopsying peripheral lung lesions.Examination of biopsied samples indicated the patient had a pulmonary Streptococcus parasanguinis infection,which was treated with antibiotics instead of more invasive treatment interventions.The patient’s symptoms resolved after she received a 3-wk course of oral linezolid.Comparisons of pretreatment and post-treatment CT scans revealed absorption of some lung lesions within 7 mo of hospital discharge.CONCLUSION ENB-guided TBLB biopsying of peripheral lung lesions in this child is a safe,well-tolerated,and effective alternative to conventional interventions.
基金The workis supported bythe Open Foundation of State Key Laboratory of Hydrology-Water Resources Hydraulic Engineering,Hohai University(Grant No.2005409111)
文摘By use of bathymetric chart, recent change of the riverbed in the North Passage of the Yangtze Estuary has been studied in this paper. The main channel of the upper, middle and lower （section） in the North Passage has been successively eroded and its groin field significantly deposited. At the same time, sediment has been deposited on the entrance region. Erosion and deposition had responded rapidly to the construction of the regulation engineering. There was about one year duration of lagging between erosion in the deep channel and the construction of the regulation engineering. The siltation lag of time in the groin field varied with the initial depth, but the average deposited thickness was about 0.5 m per year. Volumetric analysis demonstrates that there is a increasing trend of siltation in the North Passage after 2002, because of the difference in duration and quantity between erosion in the deep channel and deposition in the groin field. The water volume of the North Passage was reduced by =9% （280 million m^3） between 2002 and 2006. Sediment budget reveals that the main sediment deposited in the North Passage takes its source from the river and the ocean. The decreasing water volume was attributable to shoaling in the groin field. Its triggering factors for increased sedimentation are the navigational improvements（jetties and groins） after 1998, which altered the passage boundary and destroyed the equilibrium state on the average ebb and flood sediment fluxes. The establishment of a stable estuary is attributed to a reduction in depth of the groin field. The forecast on the sediment deposition quantity and continuous infilling time in the groin system is about 325 × 10^6m^3 and 6 - 7 years, respectively.
文摘Purpose: Professional high speed sea navigational procedures are based on turn points, courses, dangers and steering cues in the environment. Since navigational aids have become less expensive and due to the fact that electronic sea charts can be integrated with both radar and transponder information, it may be assumed that traditional navigation by using paper based charts and radar will play a less significant role in the future, especially among less experienced navigators. Possible navigational differences between experienced and non-experienced boat drivers is thus of interest with regards to their use of navigational aids. It may be assumed that less experienced navigators rely too much on the information given by the electronic sea chart, despite the fact that it is based on GPS information that can be questioned, especially in littoral waters close to land. Method: This eye tracking study investigates gaze behaviour from 16 ex perienced and novice boat drivers during high speed navigation at sea. Results: The results show that the novice drivers look at objects that are close to themselves, like instrumentation, while the experienced look more at objects far away from the boat. This is in accordance with previous research on car drivers. Further, novice boat drivers used the electronic navigational aids to a larger extent than the experienced, especially during high speed conditions. The experienced drivers focused much of their attention on objects outside the boat. Conclusions: The findings verify that novice boat drivers tend to rely on electronic navigational aids. Experienced drivers presumably use the navigational aids to verify what they have observed in the surrounding environment and further use the paper based sea chart to a larger extent than the novice drivers.
基金sponsor from the National Natural Science Foundation of China(NSFC)(Grant No.51809207).
文摘Due to the flammability and explosive nature of liquefied natural gas(LNG),an extremely strict process is followed for the transporta-tion of LNG carriers in China.Particularly,no LNG carriers are operating in inland rivers within the country.Therefore,to ensure the future navigation safety of LNG carriers entering the Yangtze River,the risk sources of LNG carriers’navigation safety must be identi-fied and evaluated.Based on the Delphi and expert experience method,this paper analyses and discusses the navigation risk factors of LNG carriers in the lower reaches of the Yangtze River from four aspects(human,ship,environment and management),identifies 12 risk indicators affecting the navigation of LNG carriers and establishes a risk evaluation index system.Further,an entropy weight fuzzy model is utilized to reduce the influence of subjective judgement on the index weight as well as to conduct a segmented and overall evaluation of LNG navigation risks in the Baimaosha Channel.Finally,the cloud model is applied to validate the consistent feasibility of the entropy weight fuzzy model.The research results indicate that the method provides effective technical support for further study on the navigation security of LNG carriers in inland rivers.
基金funded by the Science for earthquake Resilience(No.XH24014YC)the Sixth Phase“169 Project”Scientific Research Project of Zhenjiang City(No.25)+1 种基金the Scientific Research Fund from Institute of Seismology,CEA and National Institute of Natural Hazards,Ministry of Emergency Management of China(No.IS202216316)the Open Research Fund of the National Field Observation and Research Station for Gravity and Solid Tides,Wuhan(Nos.WHYMZ202113 and WHYWZ202301)。
文摘An M6.2 earthquake struck Jishishan County,Gansu,on December 18,2023,with its epicenter located in the arc-shaped tectonic belt formed by the Lajishan-Jishishan Fault.Continuous high-rate global navigational satellite system(GNSS)data were utilized to simulate real-time data resolution,enabling the rapid determination of coseismic static and dynamic deformation caused by the earthquake and the estimation of empirical magnitude.Far-field body waves served as constraints for the source rupture process,facilitating the analysis of potential seismogenic fault structures.GNSS stations within 30 km of the epicenter exhibited significant coseismic responses:horizontal peak displacement and velocity reached approximately 6.3 cm and 6.1 cm/s,respectively.Additionally,quasi-real-time differential positioning and post-event precise point positioning results were consistent throughout the source process.Vertical velocity,calculated via epoch-by-epoch differential velocity determination,showed clear coseismic signals,with peak values increasing to 2.6 cm/s.The empirical magnitude,based on displacement,was 5.99,while the magnitude derived from the velocity waveform amplitude was 6.05,both consistent with the moment magnitude.The dynamic displacement distribution preliminarily suggests directional effects of northward rupture propagation,aligning with subsequent aftershock occurrences.Finite fault inversion results,based on the two nodal planes of the focal mechanism,indicate that asperity ruptures concentrated at the hypocenter played a major role.These ruptures propagated from the hypocenter to shallow regions and northward,lasting approximately 10 s.Although the coseismic deformation determined by sparse high-rate GNSS cannot constrain the specific fault dip angle,the relationship between rupture propagation direction from the seismic source model and aftershock distribution suggests a northeast-dipping fault.Moreover,seismic source models representing single faults as geometric structures can only simulate permanent formations.In contrast,the conjugate fault model,which aligns with aftershock distributions,more accurately explains high-rate GNSS displacement waveforms.Considering both regional tectonics and geological survey results,the seismogenic fault is believed to be a local northeast-dipping blind thrust fault.Northward rupture propagation may have caused the movement of conjugate faults.This study is an effective case of using high-rate GNSS for rapid earthquake response,providing a reference basis for understanding the seismic activity patterns and earthquake disaster prevention in the region.
基金supported by the National Key Research and De-velopment Project (2019YFB1600600)the Natural Science Foun-dation of Hubei Province (2020CFB691)+2 种基金the National Natu-ral Science Foundation of China (51609228)the research project of Hubei Vocational and Technical Education Association (ZJGA201928)supported by the European Union’s Horizon 2020 Research and Innovation Programme RISE under grant agreement No.823759 (REMESH).
文摘This paper proposes a safety evaluation model of inland waterway ship navigation based on the fuzzy theory and evidential reasoning(ER)approach.The proposed model is a three-level hierarchical system consisting of 18 indicators that are identified and determined through literature review and expert surveys.By using fuzzy theory,the factors of the index level are converted into belief distributions,and the information of indicators within each level is merged by using the ER approach so that the evaluation of the ship’s navigation safety can be realized.This model can deal with multi-source information and both qualitative and quantitative indicators in an integrated framework.Some case studies on the safety status of ships navigating in the middle reaches of the Yangtze River during dry season are conducted to validate the feasibility and practicability of the proposed model.The results show that the risk levels obtained from the proposed model are consistent with the real-life situation to a large extent.The novel model proposed in this study provides a useful reference for maritime safety management and will help managers and decision-makers in the risk prevention and early warning of inland waterway transportation accidents.
基金funded by National Natural Science Foundation of China(No.82272134)Innovative Research Group Project of the National Natural Science Foundation of China(No.82272134,Xiao-lei Chen).
文摘Background and Objective Electromagnetic navigation technology has demonstrated significant potential in enhancing the accuracy and safety of neurosurgical procedures.However,traditional electromagnetic navigation systems face challenges such as high equipment costs,complex operation,bulky size,and insufficient anti-interference performance.To address these limitations,our study developed and validated a novel portable electromagnetic neuronavigation system designed to improve the precision,accessibility,and clinical applicability of electromagnetic navigation technology in cranial surgery.Methods The software and hardware architecture of a portable neural magnetic navigation system was designed.The key technologies of the system were analysed,including electromagnetic positioning algorithms,miniaturized sensor design,optimization of electromagnetic positioning and navigation algorithms,anti-interference signal processing methods,and fast three-dimensional reconstruction algorithms.A prototype was developed,and its accuracy was tested.Finally,a preliminary clinical application evaluation was conducted.Results This study successfully developed a comprehensive portable electromagnetic neuronavigation system capable of achieving preoperative planning,intraoperative real-time positioning and navigation,and postoperative evaluation of navigation outcomes.Through rigorous collaborative testing of the system’s software and hardware,the accuracy of electromagnetic neuronavigation has been validated to meet clinical requirements.Conclusions This study developed a portable neuroelectromagnetic navigation system and validated its effectiveness and safety through rigorous model testing and preliminary clinical applications.The system is characterized by its compact size,high precision,excellent portability,and user-friendly operation,making it highly valuable for promoting navigation technology and advancing the precision and minimally invasive nature of neurosurgical procedures.
基金supported by the Basic Science Center Project of the National Natural Science Foundation of China(42388102)the National Natural Science Foundation of China(42174030)+2 种基金the Special Fund of Hubei Luojia Laboratory(220100020)the Major Science and Technology Program for Hubei Province(2022AAA002)the Fundamental Research Funds for the Central Universities of China(2042022dx0001 and 2042023kfyq01)。
文摘Nonlinear variations in the coordinate time series of global navigation satellite system(GNSS) reference stations are strongly correlated with surface displacements caused by environmental loading effects,including atmospheric, hydrological, and nontidal ocean loading. Continuous improvements in the accuracy of surface mass loading products, performance of Earth models, and precise data-processing technologies have significantly advanced research on the effects of environmental loading on nonlinear variations in GNSS coordinate time series. However, owing to theoretical limitations, the lack of high spatiotemporal resolution surface mass observations, and the coupling of GNSS technology-related systematic errors, environmental loading and nonlinear GNSS reference station displacements remain inconsistent. The applicability and capability of these loading products across different regions also require further evaluation. This paper outlines methods for modeling environmental loading, surface mass loading products, and service organizations. In addition, it summarizes recent advances in applying environmental loading to address nonlinear variations in global and regional GNSS coordinate time series. Moreover, the scientific questions of existing studies are summarized, and insights into future research directions are provided. The complex nonlinear motion of reference stations is a major factor limiting the accuracy of the current terrestrial reference frame. Further refining the environmental load modeling method, establishing a surface mass distribution model with high spatiotemporal resolution and reliability, exploring other environmental load factors such as ice sheet and artificial mass-change effects, and developing an optimal data-processing model and strategy for reprocessing global reference station data consistently could contribute to the development of a millimeter-level nonlinear motion model for GNSS reference stations with actual physical significance and provide theoretical support for establishing a terrestrial reference frame with 1 mm accuracy by 2050.
文摘Terrain Aided Navigation(TAN)technology has become increasingly important due to its effectiveness in environments where Global Positioning System(GPS)is unavailable.In recent years,TAN systems have been extensively researched for both aerial and underwater navigation applications.However,many TAN systems that rely on recursive Unmanned Aerial Vehicle(UAV)position estimation methods,such as Extended Kalman Filters(EKF),often face challenges with divergence and instability,particularly in highly non-linear systems.To address these issues,this paper proposes and investigates a hybrid two-stage TAN positioning system for UAVs that utilizes Particle Filter.To enhance the system’s robustness against uncertainties caused by noise and to estimate additional system states,a Fuzzy Particle Filter(FPF)is employed in the first stage.This approach introduces a novel terrain composite feature that enables a fuzzy expert system to analyze terrain non-linearities and dynamically adjust the number of particles in real-time.This design allows the UAV to be efficiently localized in GPS-denied environments while also reducing the computational complexity of the particle filter in real-time applications.In the second stage,an Error State Kalman Filter(ESKF)is implemented to estimate the UAV’s altitude.The ESKF is chosen over the conventional EKF method because it is more suitable for non-linear systems.Simulation results demonstrate that the proposed fuzzy-based terrain composite method achieves high positional accuracy while reducing computational time and memory usage.
基金Supported by the National Natural Science Foundation of China(U23A20487)the National Key R&D Program of China(2022YFB3206000)+1 种基金Dr.Li Dak Sum&Yip Yio Chin Development Fund for Regenerative Medicine,Zhejiang Universitythe National Natural Science Foundation of China(61975172).
文摘Fluorescence imaging in the second near-infrared window(NIR-II,900-1880 nm)offers high signalto-background ratio(SBR),enhanced definition,and superior tissue penetration,making it ideal for real-time surgical navigation.However,with single-channel imaging,surgeons must frequently switch between the surgi⁃cal field and the NIR-II images on the monitor.To address this,a coaxial dual-channel imaging system that com⁃bines visible light and 1100 nm longpass(1100LP)fluorescence was developed.The system features a custom⁃ized coaxial dual-channel lens with optimized distortion,achieving precise alignment with an error of less than±0.15 mm.Additionally,the shared focusing mechanism simplifies operation.Using FDA-approved indocya⁃nine green(ICG),the system was successfully applied in dual-channel guided rat lymph node excision,and blood supply assessment of reconstructed human flap.This approach enhances surgical precision,improves opera⁃tional efficiency,and provides a valuable reference for further clinical translation of NIR-II fluorescence imaging.
文摘With the increase of international trade activities and the gradual melting of the polar ice cap,the importance of the Arctic route for marine transportation has been emphasized.Prediction of the polar navigation window period is crucial for navigating in the Arctic route,which is of great significance to the selection of the route and the optimization of navigation.This paper introduces the establishment of a risk index system,determination of risk index weight,establishment of a risk evaluation model,and prediction algorithm for the window period.In addition,data sources of both environmental factors and ship factors are introducted,and their shortcomings are analyzed,followed by introduction of various methods involved in window prediction and analysis of their advantages and disadvantages.The quantitative risk evaluation and window period algorithm can provide a reference for the research of polar navigation window period prediction.
基金supported by the National Level Project of China (No. 2020-JCJQ-ZQ-059)。
文摘1. Introduction Celestial navigation is a kind of navigation with a long history.With the increasing demand for intelligent autonomy and antielectromagnetic interference in spacecraft, celestial navigation has become one of the current research hotspots in spacecraft autonomous navigation. Spacecraft face complex electromagnetic interference in orbit. The time-varying, non-Gaussian interference from internal devices and external environment can lead to measurement distortion.
基金supported by the National Natural Science Foundation of China(No.U2037602)。
文摘In order to address the challenges encountered in visual navigation for asteroid landing using traditional point features,such as significant recognition and extraction errors,low computational efficiency,and limited navigation accuracy,a novel approach for multi-type fusion visual navigation is proposed.This method aims to overcome the limitations of single-type features and enhance navigation accuracy.Analytical criteria for selecting multi-type features are introduced,which simultaneously improve computational efficiency and system navigation accuracy.Concerning pose estimation,both absolute and relative pose estimation methods based on multi-type feature fusion are proposed,and multi-type feature normalization is established,which significantly improves system navigation accuracy and lays the groundwork for flexible application of joint absolute-relative estimation.The feasibility and effectiveness of the proposed method are validated through simulation experiments through 4769 Castalia.
文摘As the core information infrastructure of modern information warfare,the offensive and defensive confrontations of satellite navigation systems have given rise to navigation warfare,which focuses on seizing control of navigation resources.Based on the space segment,control segment,and user segment of satellite navigation systems,this paper systematically constructs an offensive-defensive technology system for navigation warfare,and deeply analyzes core measures such as signal enhancement and suppression,autonomous navigation and link jamming,anti-jamming reception,and integrated navigation.It extracts key technologies including adaptive nulling antennas,joint filtering,and multi-dimensional combined jamming,and discusses the technical effectiveness of these technologies by incorporating relevant cases.The advantages of navigation warfare stem from multi-segment coordination and technological inte-gration.In the future,the development directions of navigation warfare will focus on three aspects:enhancing satellite capabilities,tackling core technical challenges,and building a multi-dimensional system.
基金supported in part by the Doctoral Initiation Fund of Nanchang Hangkong University(No.EA202403107)Jiangxi Province Early Career Youth Science and Technology Talent Training Project(No.CK202403509).
文摘This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification methodology for practical implementation of vision-based navigation technology on the microsatellite platform.Firstly,a low power consumption,light weight,and high performance vision-based relative navigation optical sensor is designed.Subsequently,a set of ground verification system is designed for the hardware-in-the-loop testing of the vision-based relative navigation systems.Finally,the designed vision-based relative navigation optical sensor and the proposed angles-only navigation algorithms are tested on the ground verification system.The results verify that the optical simulator after geometrical calibration can meet the requirements of the hardware-in-the-loop testing of vision-based relative navigation systems.Based on experimental results,the relative position accuracy of the angles-only navigation filter at terminal time is increased by 25.5%,and the relative speed accuracy is increased by 31.3% compared with those of optical simulator before geometrical calibration.
文摘The Global Navigation Satellite System(GNSS)has been widely adopted in numerous fields,including intelligent transportation,remote sensing,and aeronautical and astronautical engineering.As new navigation approaches,technologies,and applications continue to emerge,they attract significant global attention.Ensuring reliable positioning solutions with high accuracy,strong anti-interference capabilities,high availability and low integrity risks has become increasingly critical.
基金Science and Education Department Harbin Health Committee Project。
文摘Objective:To observe the guiding role of image navigation technology in the treatment of patients with tuberculosis.Methods:A total of 188 patients with multidrug-resistant tuberculosis(MDR-TB)and rifampin-resistant tuberculosis(RR-TB)who were hospitalized in the hospital from September 2023 to September 2024 were included.After random equal division,94 patients were included in the control group and received systemic anti-tuberculosis chemotherapy;94 patients were included in the treatment group.Based on systemic anti-tuberculosis treatment,digital subtraction angiography(DSA)technology was used to inject targeted drugs into the bronchial lumen through bronchoscopy to complete anti-tuberculosis treatment.The changes in sputum bacteria and imaging were observed in the two groups.Results:The sputum negative conversion rate in the treatment group was significantly higher than that in the control group(86.2%;70.2%)(u=2.74,P<0.01).The absorption rate of CT imaging lesions(significant absorption)was significantly higher than that of the control group(83.0%;50%)(u=2.45,P<0.05).The closure rate of chest CT cavities was significantly higher than that of the control group(74.2%;39.1%)(u=2.20,P<0.05).During the treatment process,the improvement of clinical symptoms was significantly higher than that of the control group,and the difference was statistically significant.There was no statistically significant difference in the incidence of adverse reactions between the two groups(x^(2)=0.434,P>0.05).Conclusion:Based on DSA,targeted drug infusion within the bronchoscope can significantly improve the efficacy of the disease,with mild adverse reactions that patients can tolerate.It is worthy of promotion and application.
基金co-supported by the National Natural Science Foundation of China(Nos.92371201 and 52192633)the Natural Science Foundation of Shaanxi Province of China(No.2022JC-03)the Aeronautical Science Foundation of China(No.ASFC-20220019070002)。
文摘In multiple Unmanned Aerial Vehicles(UAV)systems,achieving efficient navigation is essential for executing complex tasks and enhancing autonomy.Traditional navigation methods depend on predefined control strategies and trajectory planning and often perform poorly in complex environments.To improve the UAV-environment interaction efficiency,this study proposes a multi-UAV integrated navigation algorithm based on Deep Reinforcement Learning(DRL).This algorithm integrates the Inertial Navigation System(INS),Global Navigation Satellite System(GNSS),and Visual Navigation System(VNS)for comprehensive information fusion.Specifically,an improved multi-UAV integrated navigation algorithm called Information Fusion with MultiAgent Deep Deterministic Policy Gradient(IF-MADDPG)was developed.This algorithm enables UAVs to learn collaboratively and optimize their flight trajectories in real time.Through simulations and experiments,test scenarios in GNSS-denied environments were constructed to evaluate the effectiveness of the algorithm.The experimental results demonstrate that the IF-MADDPG algorithm significantly enhances the collaborative navigation capabilities of multiple UAVs in formation maintenance and GNSS-denied environments.Additionally,it has advantages in terms of mission completion time.This study provides a novel approach for efficient collaboration in multi-UAV systems,which significantly improves the robustness and adaptability of navigation systems.
文摘Since its inception in the 1960s,light detection and ranging(LiDAR)technology has demonstrated great potential in various fields such as autonomous driving,robot navigation,and environmental monitoring due to its high precision,high resolution,and strong anti-interference capability.This paper reviews the development history,technical principles,application fields,and future development trends of LiDAR technology.It introduces the technical applications of LiDAR technology in autonomous driving,robot navigation,and environmental monitoring,and explores the development direction of SLAM algorithms in multi-sensor fusion and real-time map construction,providing a reference basis for the development and research of LiDAR.
基金supported by the Sichuan Science and Technology Program(2025ZNSFSC0005).
文摘Robot navigation in complex crowd service scenarios,such as medical logistics and commercial guidance,requires a dynamic balance between safety and efficiency,while the traditional fixed reward mechanism lacks environmental adaptability and struggles to adapt to the variability of crowd density and pedestrian motion patterns.This paper proposes a navigation method that integrates spatiotemporal risk field modeling and adaptive reward optimization,aiming to improve the robot’s decision-making ability in diverse crowd scenarios through dynamic risk assessment and nonlinear weight adjustment.We construct a spatiotemporal risk field model based on a Gaussian kernel function by combining crowd density,relative distance,andmotion speed to quantify environmental complexity and realize crowd-density-sensitive risk assessment dynamically.We apply an exponential decay function to reward design to address the linear conflict problem of fixed weights in multi-objective optimization.We adaptively adjust weight allocation between safety constraints and navigation efficiency based on real-time risk values,prioritizing safety in highly dense areas and navigation efficiency in sparse areas.Experimental results show that our method improves the navigation success rate by 9.0%over state-of-the-art models in high-density scenarios,with a 10.7%reduction in intrusion time ratio.Simulation comparisons validate the risk field model’s ability to capture risk superposition effects in dense scenarios and the suppression of near-field dangerous behaviors by the exponential decay mechanism.Our parametric optimization paradigm establishes an explicit mapping between navigation objectives and risk parameters through rigorous mathematical formalization,providing an interpretable approach for safe deployment of service robots in dynamic environments.
