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
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
Unmanned aerial vehicles(UAVs),especially quadcopters,have become indispensable in numerous industrial and scientific applications due to their flexibility,lowcost,and capability to operate in dynamic environments.Thi...Unmanned aerial vehicles(UAVs),especially quadcopters,have become indispensable in numerous industrial and scientific applications due to their flexibility,lowcost,and capability to operate in dynamic environments.This paper presents a complete design and implementation of a compact autonomous quadcopter capable of trajectory tracking,object detection,precision landing,and real-time telemetry via long-range communication protocols.The system integrates an onboard flight controller running real-time sensor fusion algorithms,a vision-based detection system on a companion single-board computer,and a telemetry unit using Long Range(LoRa)communication.Extensive flight tests were conducted to validate the system’s stability,communication range,and autonomous capabilities.Potential applications in law enforcement,agriculture,search and rescue,and environmental monitoring are also discussed.展开更多
The satellite-based augmentation system(SBAS)provides differential and integrity augmentation services for life safety fields of aviation and navigation.However,the signal structure of SBAS is public,which incurs a ri...The satellite-based augmentation system(SBAS)provides differential and integrity augmentation services for life safety fields of aviation and navigation.However,the signal structure of SBAS is public,which incurs a risk of spoofing attacks.To improve the anti-spoofing capability of the SBAS,European Union and the United States conduct research on navigation message authentication,and promote the standardization of SBAS message authentication.For the development of Beidou satellite-based augmentation system(BDSBAS),this paper proposes navigation message authentication based on the Chinese commercial cryptographic standards.Firstly,this paper expounds the architecture and principles of the SBAS message authentication,and then carries out the design of timed efficient streaming losstolerant authentication scheme(TESLA)and elliptic curve digital signature algorithm(ECDSA)authentication schemes based on Chinese commercial cryptographic standards,message arrangement and the design of over-the-air rekeying(OTAR)message.Finally,this paper conducts a theoretical analysis of the time between authentications(TBA)and maximum authentication latency(MAL)for L5 TESLA-I and L5 ECDSA-Q,and further simulates the reception time of OTAR message,TBA and MAL from the aspects of OTAR message weight and demodulation error rate.The simulation results can provide theoretical supports for the standardization of BDSBAS message authentication.展开更多
The thoracic duct(TD),the largest lymphatic vessel in the human body,plays a critical role in returning lymph to the circulatory system.However,its dynamic,distensible nature and concealed anatomical location make int...The thoracic duct(TD),the largest lymphatic vessel in the human body,plays a critical role in returning lymph to the circulatory system.However,its dynamic,distensible nature and concealed anatomical location make intraoperative visualization critically challenging and increase the risk of injury.Real-time,high-resolution assessment of TD leaks remains an urgent clinical need.Here,we present a breakthrough molecular engineering strategy that leverages an intestinally lipophilic fluorescent formulation for dynamic in vivo TD imaging.Our rationally designed cyanine derivative IR790+,known for its rapid membrane permeability and endoplasmic reticulum(ER)targeting localization,demonstrates unprecedented chylomicron affinity,which subsequently transports the dye through the lymphatic system to the TD.Notably,dynamic,high-contrast intraoperative TD imaging is achieved from rat models to swine models.Administered orally as near-infrared(NIR)fluorescent contrast agent,this ultra-stable IR790+@oil formulation,engineered via flash nanoprecipitation,surpasses conventional counterparts by enabling non-invasive,real-time identification of TD.Intriguingly,this first-reported ER-targeting NIR formulation,delivered orally,represents a paradigm shift in fluorescence-guided surgery,significantly improving intraoperative accuracy.展开更多
Objectives:One of the most notable challenges in endoscopic procedures is maintaining correct orientation.Mental rotation exercise(MRE)has been suggested as a potential aid for improving orientation.However,there is a...Objectives:One of the most notable challenges in endoscopic procedures is maintaining correct orientation.Mental rotation exercise(MRE)has been suggested as a potential aid for improving orientation.However,there is a lack of research on designing MREs with varying difficultylevels for training purposes.Furthermore,few studies provide solid evidence linking MRE difficultylevels with cognitive load measurements.This study aims to address this gap by investigating the correlation between the MRE difficultylevels and participants’cognitive load,as measured by pupil dilation.Method:We recruited 33 participants to perform MREs on a computer equipped with a screen-mounted eye-tracker.The test consisted of 15 MREs,with the first10 relatively easy(traditional cube)and the next 5 more complex(invented molecule).The participants’eye movements during MREs were recorded.The participants’MRE scores and pupil dilation were obtained and compared between two MRE difficultylevels.Results:The participants who performed traditional cube MREs achieved significantlybetter MRE scores(0.77±0.11 vs.0.58±0.03,p<0.001)and lower pupil dilation(0.27±0.04 pixels vs.0.47±0.09 pixels,p<0.001)than did those who performed the invented molecule MREs.Moreover,there were significant negative correlations(r=0.62,p=0.015)between pupil dilation and MRE scores.Conclusions:The results revealed a significantnegative correlation between MRE scores and pupil dilation.The more challenging MRE questions led to worse MRE scores but increased pupil dilation.The MRE difficultylevels can be evaluated not only by the degrees or dimensions with which the objects were rotated but also by the participants’MRE scores and pupil dilation.The results of this study provide a basis for training orientation skills in endoscopy using MREs.By incorporating MREs with varying difficultylevels,customized training programs can be developed to enhance camera navigation in endoscopic and laparoscopic procedures.展开更多
Surgical navigation has evolved significantly through advances in augmented reality,virtual reality,and mixed reality,improving precision and safety across many clinical applications,including neurosurgery,maxillofaci...Surgical navigation has evolved significantly through advances in augmented reality,virtual reality,and mixed reality,improving precision and safety across many clinical applications,including neurosurgery,maxillofacial,spinal,and arthroplasty procedures.By integrating preoperative imaging with real-time intraoperative data,these systems provide dynamic guidance,reduce radiation exposure,and minimize tissue damage.Key challenges persist,including intraoperative registration accuracy,flexible tissue deformation,respiratory compensation,and real-time imaging quality.Emerging solutions include artificial intelligence-driven segmentation,deformation-field modeling,and hybrid registration techniques.Future developments will include lightweight,portable systems,improved non-rigid registration algorithms,and greater clinical adoption.Despite advances in rigid-tissue applications,soft-tissue navigation requires additional innovation to address motion variability and registration reliability,ultimately advancing minimally invasive surgery and precision medicine.展开更多
Background:Artificial intelligence(AI)-assisted threedimensional(3D)surgical platforms,integrated with augmented reality,have the potential to improve intraoperative anatomical recognition and provide surgeons with an...Background:Artificial intelligence(AI)-assisted threedimensional(3D)surgical platforms,integrated with augmented reality,have the potential to improve intraoperative anatomical recognition and provide surgeons with an immersive,dynamic operating environment during urooncological procedures.This review aims to examine the current applications of AI in robotic uro-oncology,with a particular focus on its role in facilitating intraoperative navigation during complex surgeries.Methods:A systematic literature search was performed across PubMed,the National Library of Medicine,MEDLINE,the Cochrane Central Register of Controlled Trials(CENTRAL),ClinicalTrials.gov,and Google Scholar to identify relevant studies published up to July 2025.The search strategy incorporated a predefined set of keywords,including AI,machine learning,radical prostatectomy(RP),robotic-assisted radical prostatectomy(RARP),robotassisted partial nephrectomy(RAPN),and robot-assisted radical cystectomy(RARC).Only clinical trials,full-text peer-reviewed publications,and original research articles were included.Studies were eligible for inclusion if they evaluated or described applications of AI in RARP,RAPN,or RARC.Results:Technological advancements have substantially transformed the field of uro-oncologic surgery.In particular,AI and AI-assisted intraoperative navigation in RARP demonstrate considerable potential to objectively assess surgical performance and predict clinical outcomes.In RAPN,the adoption of preoperative,interactive 3D virtualmodels for surgical planning has influenced surgical decisions,thus,enhanced precision in resection planning correlates with superior nephron-sparing outcomes and optimized selective clamping.AI applications in RARC,techniques such as augmented reality(AR)can overlay critical information on the surgical field,by facilitating navigation through complex anatomical planes and enhancing identification of critical structures.Conclusion:AI appears to enhance robotic uro-oncologic procedures by increasing operative precision and supporting individualised surgical treatment strategies.展开更多
Autonomous navigation is a key technology for unmanned motion platforms to perform their tasks smoothly.The current approaches for daytime polarization navigation have been extensively researched.However,the polarizat...Autonomous navigation is a key technology for unmanned motion platforms to perform their tasks smoothly.The current approaches for daytime polarization navigation have been extensively researched.However,the polarization light intensity is the fundamental information within the polarization image,and the light intensity at night is 6-8 orders of magnitude lower than that during the day,which increase the noise and the loss of local polarization information due to occlusion,resulting in a significant decrease in the polarization orientation accuracy.Aimed at the problem,a bio-inspired model is introduced to denoise and enhance weak nighttime polarization patterns.Further,to address the issue of outlier interference in the occluded environment during practical application,a fast-fitting method of the solar meridian based on the anti-symmetric distribution of the polarization angle adjusted by Proportional and Differential(PD)control is proposed.The experimental results show that the method proposed in this paper achieves a dynamic orientation error Root Mean Square Error(RMSE)of 0.7°in the weak polarization mode at night and in the presence of local occlusion.The proposed method has strong robustness under weak polarization occlusion at night,and the orientation accuracy is improved by 97%and 80%in comparison to the least squares method,which provides a new method for polarization navigation at night.This effectively improves the robustness and environmental applicability of the bionic polarization compass for nighttime applications.展开更多
Microelectromechanical systems(MEMS)technology has gained significant attention over the past decade for measuring inertial angular velocity.However,due to inherent complexity,MEMS gyroscopes typically feature up to t...Microelectromechanical systems(MEMS)technology has gained significant attention over the past decade for measuring inertial angular velocity.However,due to inherent complexity,MEMS gyroscopes typically feature up to ten times more parameters than traditional sensors,making selection a challenging task even for experts.This study addresses this challenge,focusing on defensive guidance,navigation,and control(GNC)systems where precise and reliable angular velocity measurement is critical to overall performance.A comprehensive mathematical model is introduced to encapsulate all key MEMS parameters,accompanied by discussions on calibration and Allan variance interpretation.For six leading MEMS gyroscope applications,namely inertial navigation,integrated navigation,autopilot systems,rotating projectiles,homing guidance,and north finding,the most critical parameters are identified,distinguishing suitable and unsuitable sensor choices.Special emphasis is placed on inertial navigation systems,where practical rules of thumb for error evaluation are derived using six degrees of freedom motion equations.Rigorous simulations demonstrate the influence of various sensor parameters through real-world case studies,including static navigation,multi-rotor attitude estimation,gimbal stabilization,and north finding via a turntable.This work aims to be a beacon for practitioners across diverse fields,empowering them to make more informed design decisions.展开更多
Unmanned Aerial Vehicle(UAV)plays a prominent role in various fields,and autonomous navigation is a crucial component of UAV intelligence.Deep Reinforcement Learning(DRL)has expanded the research avenues for addressin...Unmanned Aerial Vehicle(UAV)plays a prominent role in various fields,and autonomous navigation is a crucial component of UAV intelligence.Deep Reinforcement Learning(DRL)has expanded the research avenues for addressing challenges in autonomous navigation.Nonetheless,challenges persist,including getting stuck in local optima,consuming excessive computations during action space exploration,and neglecting deterministic experience.This paper proposes a noise-driven enhancement strategy.In accordance with the overall learning phases,a global noise control method is designed,while a differentiated local noise control method is developed by analyzing the exploration demands of four typical situations encountered by UAV during navigation.Both methods are integrated into a dual-model for noise control to regulate action space exploration.Furthermore,noise dual experience replay buffers are designed to optimize the rational utilization of both deterministic and noisy experience.In uncertain environments,based on the Twin Delay Deep Deterministic Policy Gradient(TD3)algorithm with Long Short-Term Memory(LSTM)network and Priority Experience Replay(PER),a Noise-Driven Enhancement Priority Memory TD3(NDE-PMTD3)is developed.We established a simulation environment to compare different algorithms,and the performance of the algorithms is analyzed in various scenarios.The training results indicate that the proposed algorithm accelerates the convergence speed and enhances the convergence stability.In test experiments,the proposed algorithm successfully and efficiently performs autonomous navigation tasks in diverse environments,demonstrating superior generalization results.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
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
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.
文摘Unmanned aerial vehicles(UAVs),especially quadcopters,have become indispensable in numerous industrial and scientific applications due to their flexibility,lowcost,and capability to operate in dynamic environments.This paper presents a complete design and implementation of a compact autonomous quadcopter capable of trajectory tracking,object detection,precision landing,and real-time telemetry via long-range communication protocols.The system integrates an onboard flight controller running real-time sensor fusion algorithms,a vision-based detection system on a companion single-board computer,and a telemetry unit using Long Range(LoRa)communication.Extensive flight tests were conducted to validate the system’s stability,communication range,and autonomous capabilities.Potential applications in law enforcement,agriculture,search and rescue,and environmental monitoring are also discussed.
基金supported by National Natural Science Foundation of China:Space-based occultation detection with ground-based GNSS atmospheric horizontal gradient model(41904033).
文摘The satellite-based augmentation system(SBAS)provides differential and integrity augmentation services for life safety fields of aviation and navigation.However,the signal structure of SBAS is public,which incurs a risk of spoofing attacks.To improve the anti-spoofing capability of the SBAS,European Union and the United States conduct research on navigation message authentication,and promote the standardization of SBAS message authentication.For the development of Beidou satellite-based augmentation system(BDSBAS),this paper proposes navigation message authentication based on the Chinese commercial cryptographic standards.Firstly,this paper expounds the architecture and principles of the SBAS message authentication,and then carries out the design of timed efficient streaming losstolerant authentication scheme(TESLA)and elliptic curve digital signature algorithm(ECDSA)authentication schemes based on Chinese commercial cryptographic standards,message arrangement and the design of over-the-air rekeying(OTAR)message.Finally,this paper conducts a theoretical analysis of the time between authentications(TBA)and maximum authentication latency(MAL)for L5 TESLA-I and L5 ECDSA-Q,and further simulates the reception time of OTAR message,TBA and MAL from the aspects of OTAR message weight and demodulation error rate.The simulation results can provide theoretical supports for the standardization of BDSBAS message authentication.
基金supported by the National Natural Science Foundation of China(22225805,81400681,32394001,32121005)the Shanghai Science and Technology Innovation Action Plan(22Y11907200,23J21901600)the Innovation Program of Shanghai Municipal Education Commission,Shanghai Municipal Health Commission(2024ZZ2025)。
文摘The thoracic duct(TD),the largest lymphatic vessel in the human body,plays a critical role in returning lymph to the circulatory system.However,its dynamic,distensible nature and concealed anatomical location make intraoperative visualization critically challenging and increase the risk of injury.Real-time,high-resolution assessment of TD leaks remains an urgent clinical need.Here,we present a breakthrough molecular engineering strategy that leverages an intestinally lipophilic fluorescent formulation for dynamic in vivo TD imaging.Our rationally designed cyanine derivative IR790+,known for its rapid membrane permeability and endoplasmic reticulum(ER)targeting localization,demonstrates unprecedented chylomicron affinity,which subsequently transports the dye through the lymphatic system to the TD.Notably,dynamic,high-contrast intraoperative TD imaging is achieved from rat models to swine models.Administered orally as near-infrared(NIR)fluorescent contrast agent,this ultra-stable IR790+@oil formulation,engineered via flash nanoprecipitation,surpasses conventional counterparts by enabling non-invasive,real-time identification of TD.Intriguingly,this first-reported ER-targeting NIR formulation,delivered orally,represents a paradigm shift in fluorescence-guided surgery,significantly improving intraoperative accuracy.
文摘Objectives:One of the most notable challenges in endoscopic procedures is maintaining correct orientation.Mental rotation exercise(MRE)has been suggested as a potential aid for improving orientation.However,there is a lack of research on designing MREs with varying difficultylevels for training purposes.Furthermore,few studies provide solid evidence linking MRE difficultylevels with cognitive load measurements.This study aims to address this gap by investigating the correlation between the MRE difficultylevels and participants’cognitive load,as measured by pupil dilation.Method:We recruited 33 participants to perform MREs on a computer equipped with a screen-mounted eye-tracker.The test consisted of 15 MREs,with the first10 relatively easy(traditional cube)and the next 5 more complex(invented molecule).The participants’eye movements during MREs were recorded.The participants’MRE scores and pupil dilation were obtained and compared between two MRE difficultylevels.Results:The participants who performed traditional cube MREs achieved significantlybetter MRE scores(0.77±0.11 vs.0.58±0.03,p<0.001)and lower pupil dilation(0.27±0.04 pixels vs.0.47±0.09 pixels,p<0.001)than did those who performed the invented molecule MREs.Moreover,there were significant negative correlations(r=0.62,p=0.015)between pupil dilation and MRE scores.Conclusions:The results revealed a significantnegative correlation between MRE scores and pupil dilation.The more challenging MRE questions led to worse MRE scores but increased pupil dilation.The MRE difficultylevels can be evaluated not only by the degrees or dimensions with which the objects were rotated but also by the participants’MRE scores and pupil dilation.The results of this study provide a basis for training orientation skills in endoscopy using MREs.By incorporating MREs with varying difficultylevels,customized training programs can be developed to enhance camera navigation in endoscopic and laparoscopic procedures.
基金Supported by the National Natural Science Foundation of China(NSFC)under Grants 62025104,62422102,62331005,62301034,and U22A2052the Beijing Natural Science Foundation-Daxing Innovation Joint Fund(L256040).
文摘Surgical navigation has evolved significantly through advances in augmented reality,virtual reality,and mixed reality,improving precision and safety across many clinical applications,including neurosurgery,maxillofacial,spinal,and arthroplasty procedures.By integrating preoperative imaging with real-time intraoperative data,these systems provide dynamic guidance,reduce radiation exposure,and minimize tissue damage.Key challenges persist,including intraoperative registration accuracy,flexible tissue deformation,respiratory compensation,and real-time imaging quality.Emerging solutions include artificial intelligence-driven segmentation,deformation-field modeling,and hybrid registration techniques.Future developments will include lightweight,portable systems,improved non-rigid registration algorithms,and greater clinical adoption.Despite advances in rigid-tissue applications,soft-tissue navigation requires additional innovation to address motion variability and registration reliability,ultimately advancing minimally invasive surgery and precision medicine.
文摘Background:Artificial intelligence(AI)-assisted threedimensional(3D)surgical platforms,integrated with augmented reality,have the potential to improve intraoperative anatomical recognition and provide surgeons with an immersive,dynamic operating environment during urooncological procedures.This review aims to examine the current applications of AI in robotic uro-oncology,with a particular focus on its role in facilitating intraoperative navigation during complex surgeries.Methods:A systematic literature search was performed across PubMed,the National Library of Medicine,MEDLINE,the Cochrane Central Register of Controlled Trials(CENTRAL),ClinicalTrials.gov,and Google Scholar to identify relevant studies published up to July 2025.The search strategy incorporated a predefined set of keywords,including AI,machine learning,radical prostatectomy(RP),robotic-assisted radical prostatectomy(RARP),robotassisted partial nephrectomy(RAPN),and robot-assisted radical cystectomy(RARC).Only clinical trials,full-text peer-reviewed publications,and original research articles were included.Studies were eligible for inclusion if they evaluated or described applications of AI in RARP,RAPN,or RARC.Results:Technological advancements have substantially transformed the field of uro-oncologic surgery.In particular,AI and AI-assisted intraoperative navigation in RARP demonstrate considerable potential to objectively assess surgical performance and predict clinical outcomes.In RAPN,the adoption of preoperative,interactive 3D virtualmodels for surgical planning has influenced surgical decisions,thus,enhanced precision in resection planning correlates with superior nephron-sparing outcomes and optimized selective clamping.AI applications in RARC,techniques such as augmented reality(AR)can overlay critical information on the surgical field,by facilitating navigation through complex anatomical planes and enhancing identification of critical structures.Conclusion:AI appears to enhance robotic uro-oncologic procedures by increasing operative precision and supporting individualised surgical treatment strategies.
基金co-supported by the Excellent Youth Foundation of Shanxi Province,China(No.202103021222011)the Key Research and Development project of Shanxi Province of China(No.202202020101002)+3 种基金the Fundamental Research Program of Shanxi Province of China(No.202303021211150)the Aviation Science Foundation of China(No.2022Z0220U0002)the Graduate Education Innovation Plan Project of Shanxi Province,China(No.2023KY588)the Shanxi Province Key Laboratory of Quantum Sensing and Precision Measurement,China(No.201905D121001).
文摘Autonomous navigation is a key technology for unmanned motion platforms to perform their tasks smoothly.The current approaches for daytime polarization navigation have been extensively researched.However,the polarization light intensity is the fundamental information within the polarization image,and the light intensity at night is 6-8 orders of magnitude lower than that during the day,which increase the noise and the loss of local polarization information due to occlusion,resulting in a significant decrease in the polarization orientation accuracy.Aimed at the problem,a bio-inspired model is introduced to denoise and enhance weak nighttime polarization patterns.Further,to address the issue of outlier interference in the occluded environment during practical application,a fast-fitting method of the solar meridian based on the anti-symmetric distribution of the polarization angle adjusted by Proportional and Differential(PD)control is proposed.The experimental results show that the method proposed in this paper achieves a dynamic orientation error Root Mean Square Error(RMSE)of 0.7°in the weak polarization mode at night and in the presence of local occlusion.The proposed method has strong robustness under weak polarization occlusion at night,and the orientation accuracy is improved by 97%and 80%in comparison to the least squares method,which provides a new method for polarization navigation at night.This effectively improves the robustness and environmental applicability of the bionic polarization compass for nighttime applications.
文摘Microelectromechanical systems(MEMS)technology has gained significant attention over the past decade for measuring inertial angular velocity.However,due to inherent complexity,MEMS gyroscopes typically feature up to ten times more parameters than traditional sensors,making selection a challenging task even for experts.This study addresses this challenge,focusing on defensive guidance,navigation,and control(GNC)systems where precise and reliable angular velocity measurement is critical to overall performance.A comprehensive mathematical model is introduced to encapsulate all key MEMS parameters,accompanied by discussions on calibration and Allan variance interpretation.For six leading MEMS gyroscope applications,namely inertial navigation,integrated navigation,autopilot systems,rotating projectiles,homing guidance,and north finding,the most critical parameters are identified,distinguishing suitable and unsuitable sensor choices.Special emphasis is placed on inertial navigation systems,where practical rules of thumb for error evaluation are derived using six degrees of freedom motion equations.Rigorous simulations demonstrate the influence of various sensor parameters through real-world case studies,including static navigation,multi-rotor attitude estimation,gimbal stabilization,and north finding via a turntable.This work aims to be a beacon for practitioners across diverse fields,empowering them to make more informed design decisions.
基金the Collaborative Innovation Project of Shanghai,China for the financial support。
文摘Unmanned Aerial Vehicle(UAV)plays a prominent role in various fields,and autonomous navigation is a crucial component of UAV intelligence.Deep Reinforcement Learning(DRL)has expanded the research avenues for addressing challenges in autonomous navigation.Nonetheless,challenges persist,including getting stuck in local optima,consuming excessive computations during action space exploration,and neglecting deterministic experience.This paper proposes a noise-driven enhancement strategy.In accordance with the overall learning phases,a global noise control method is designed,while a differentiated local noise control method is developed by analyzing the exploration demands of four typical situations encountered by UAV during navigation.Both methods are integrated into a dual-model for noise control to regulate action space exploration.Furthermore,noise dual experience replay buffers are designed to optimize the rational utilization of both deterministic and noisy experience.In uncertain environments,based on the Twin Delay Deep Deterministic Policy Gradient(TD3)algorithm with Long Short-Term Memory(LSTM)network and Priority Experience Replay(PER),a Noise-Driven Enhancement Priority Memory TD3(NDE-PMTD3)is developed.We established a simulation environment to compare different algorithms,and the performance of the algorithms is analyzed in various scenarios.The training results indicate that the proposed algorithm accelerates the convergence speed and enhances the convergence stability.In test experiments,the proposed algorithm successfully and efficiently performs autonomous navigation tasks in diverse environments,demonstrating superior generalization results.
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.
