Shallow landslides are strongly controlled by near-surface lithological variability,yet conventional geological maps are often too generalized to support accurate susceptibility assessment in complex terrains.This rev...Shallow landslides are strongly controlled by near-surface lithological variability,yet conventional geological maps are often too generalized to support accurate susceptibility assessment in complex terrains.This review synthesizes recent advances in remote sensing–based lithological mapping and evaluates their integration into landslide susceptibility modeling.Evidence from the literature indicates that remote sensing-derived lithological products,particularly those incorporating mineralogical information and higher spatial resolution,consistently outperform traditional geological maps in improving model accuracy and spatial detail,especially in heterogeneous environments.However,key challenges remain,including scale mismatches between surface observations and subsurface controls,limited ground validation,uncertainty propagation,and restricted model transferability across regions.The review identifies multi-sensor data fusion and explainable machine learning as the most promising directions for advancing lithological discrimination and model reliability.Future progress depends on integrating remote sensing with process-based understanding,improving validation strategies,and standardizing uncertainty reporting.These developments are essential for enabling more robust,scalable,and operationally relevant landslide susceptibility assessments in complex terrains.Lastly,we describe the directions of research that focus on multi-sensor fusion,explainable machine learning,UAV(Unmanned Aerial Vehicle)-enabled validation,and standardized uncertainty reporting that can help articulate landslide susceptibility assessment,making them even more robust and operationally significant.展开更多
Aerial surveys are dynamic and continuous processes,and there are different height distributions of the ground in the measurement area,which leads to problems such as overlapping measurement areas and inaccurate altit...Aerial surveys are dynamic and continuous processes,and there are different height distributions of the ground in the measurement area,which leads to problems such as overlapping measurement areas and inaccurate altitude correction during the survey process.Commonly used terrain correction methods are based on the concept of finite elementization of ground surface radioactive sources,using GPS coordinates,radar altitude,and ground elevation distribution information from aerial surveys,combined with the sourceless efficiency calibration method to construct a response matrix,which is then inverted for surface nuclide content.However,most of the sourceless efficiency calibration methods used are numerical calculations that consider the body detector as a point detector and do not consider the changes in intrinsic detection efficiency under different incident directions of gamma rays.Therefore,when the altitude of the measurement area varies significantly or the flight altitude of the aerial survey is relatively low,such sourceless efficiency calibration method calculations tend to have a large bias,which affects the accuracy of the terrain correction.To address the above problems,this study employs a novel sourceless efficiency calibration method based on the Boolean operation of the ray deposition process and simplifies the traditional body source measurement model to a surface source measurement model to achieve fast and accurate efficiency calibration.Then,through the discretization of the measurement process,the static measurement process is superposed as equivalent to the dynamic measurement process,and the dynamic measurement response matrix is built and optimized based on the calibration method.Finally,the PSO-MLEM algorithm was used to solve the dynamic measurement response matrix to achieve dynamic terrain correction of aerial survey data.Analysis of the Baiyun'ebo test area revealed that,after applying dynamic terrain correction,the inverted anomalies in uranium(eU),thorium(eTh),and potassium(K)concentrations were closer to ground measurements(within 5.72%-30.79%)and exhibited clearer anomaly boundaries compared to traditional height-based corrections.However,owing to the inherent statistical fluctuations and characteristics of matrix inversion,higher measurement values tend to absorb lower ones,potentially enlarging the anomalous regions.Nevertheless,the highanomaly regions after inversion largely coincided with the ground truth validation,demonstrating that the proposed method can effectively correct airborne gamma spectrometry data.展开更多
In 2025,I had the honor of delivering keynote speeches at the conferences of the International Society for Diet and Activity Methods in Toronto,Canada,and the International Society of Behavioural Nutrition and Physica...In 2025,I had the honor of delivering keynote speeches at the conferences of the International Society for Diet and Activity Methods in Toronto,Canada,and the International Society of Behavioural Nutrition and Physical Activity in Auckland,Aotearoa,New Zealand.These opportunities prompted deep reflection on scientific research in general,and on physical activity and health research specifically.展开更多
To improve the navigation accuracy of an autonomous underwater vehicle （AUV）, a novel terrain passive integrated navigation system （TPINS） is presented. According to the characteristics of the underwater environme...To improve the navigation accuracy of an autonomous underwater vehicle （AUV）, a novel terrain passive integrated navigation system （TPINS） is presented. According to the characteristics of the underwater environment and AUV navigation requirements of low cost and high accuracy, a novel TPINS is designed with a configuration of the strapdown inertial navigation system （SINS）, the terrain reference navigation system （TRNS）, the Doppler velocity sonar （DVS）, the magnetic compass and the navigation computer utilizing the unscented Kalman filter （UKF） to fuse the navigation information from various navigation sensors. Linear filter equations for the extended Kalman filter （EKF）, nonlinear filter equations for the UKF and measurement equations of navigation sensors are addressed. It is indicated from the comparable simulation experiments of the EKF and the UKF that AUV navigation precision is improved substantially with the proposed sensors and the UKF when compared to the EKF. The TPINS designed with the proposed sensors and the UKF is effective in reducing AUV navigation position errors and improving the stability and precision of the AUV underwater integrated navigation.展开更多
The results from a hybrid approach that combines a mesoscale meteorological model with a diagnostic model to produce high-resolution wind fields in complex coastal topography are evaluated.The diagnostic wind model(Ca...The results from a hybrid approach that combines a mesoscale meteorological model with a diagnostic model to produce high-resolution wind fields in complex coastal topography are evaluated.The diagnostic wind model(California Meteorological Model,CALMET) with 100-m horizontal spacing was driven with outputs from the Weather Research and Forecasting(WRF) model to obtain near-surface winds for the 1-year period from 12 September 2003 to 11 September 2004.Results were compared with wind observations at four sites.Traditional statistical scores,including correlation coefficients,standard deviations(SDs) and mean absolute errors(MAEs),indicate that the wind estimates from the WRF/CALMET modeling system are produced reasonably well.The correlation coefficients are relatively large,ranging from 0.5 to 0.7 for the zonal wind component and from 0.75 to 0.85 for the meridional wind component.MAEs for wind speed range from 1.5 to 2.0 m s-1 at 10 meters above ground level(AGL) and from 2.0 to 2.5 m s-1 at 60 m AGL.MAEs for wind direction range from 30 to 40 degrees at both levels.A spectral decomposition of the time series of wind speed shows positive impacts of CALMET in improving the mesoscale winds.Moreover,combining the CALMET model with WRF significantly improves the spatial variability of the simulated wind fields.It can be concluded that the WRF/CALMET modeling system is capable of providing a detailed near-surface wind field,but the physics in the diagnostic CALMET model needs to be further improved.展开更多
Virtual simulation technology is of great importance for the teleoperation of lunar rovers during the exploration phase,as well as the design of locomotion systems,performance evaluation,and control strategy verificat...Virtual simulation technology is of great importance for the teleoperation of lunar rovers during the exploration phase,as well as the design of locomotion systems,performance evaluation,and control strategy verification during the R&D phase.The currently used simulation methods for lunar rovers have several disadvantages such as poor fidelity for wheel-soil interaction mechanics,difficulty in simulating rough terrains,and high complexity making it difficult to realize mobility control in simulation systems.This paper presents an approach for the construction of a virtual simulation system that integrates the features of 3D modeling,wheel-soil interaction mechanics,dynamics analysis,mobility control,and visualization for lunar rovers.Wheel-soil interaction experiments are carried out to test the forces and moments acted on a lunar rover’s wheel by the soil with a vertical load of 80 N and slip ratios of 0,0.03,0.05,0.1,0.2,0.3,0.4,and 0.6.The experimental results are referenced in order to set the parameters’values for the PAC2002 tire model of the ADAMS/Tire module.In addition,the rough lunar terrain is simulated with 3DS Max software after analyzing its characteristics,and a data-transfer program is developed with Matlab to simulate the 3D reappearance of a lunar environment in ADAMS.The 3D model of a lunar rover is developed by using Pro/E software and is then imported into ADAMS.Finally,a virtual simulation system for lunar rovers is developed.A path-following control strategy based on slip compensation for a six-wheeled lunar rover prototype is researched.The controller is implemented by using Matlab/Simulink to carry out joint simulations with ADAMS.The designed virtual lunar rover could follow the planned path on a rough terrain.This paper can also provide a reference scheme for virtual simulation and performance analysis of rovers moving on rough lunar terrains.展开更多
Based on the previous statistical analysis of mesoscale convective systems(MCSs)over the second-step terrain along Yangtze-Huaihe River Valley,eight representative long-lived eastward-propagating MCSs are selected for...Based on the previous statistical analysis of mesoscale convective systems(MCSs)over the second-step terrain along Yangtze-Huaihe River Valley,eight representative long-lived eastward-propagating MCSs are selected for model-based sensitivity testing to investigate the initiation and evolution of these types of MCSs as well as their impact on downstream areas.We subject each MCS to a semi-idealized(CNTL)simulation and a sensitivity(NOLH)simulation that neglects condensational heating in the formation region.The CNTL experiment reveals convection forms in the region downstream of a shortwave trough typified by persistent southwesterly winds in the low-to midtroposphere.Upon merging with other convective systems,moist convection develops into an MCS,which propagates eastward under the influence of mid-tropospheric westerlies,and moves out of the second-step terrain.The MCS then merges with pre-existing local convection over the plains;the merged convection reinforces the cyclonic wind perturbation into a mesoscale vortex at 850 hPa.While this vortex moves eastward to regions with local vortex at 850 hPa,another vortex at 925 hPa is also intensified.Finally,the vortices at 850 and 925 hPa merge together and develop into a mesoscale convective vortex(MCV).In contrast,MCSs fail to form and move eastward in the NOLH experiment.In the absence of eastward-propagating MCSs,moist convection and mesoscale vortices still appear in the plains,but the vortex strength and precipitation intensity are significantly weakened.It is suggested the eastward-propagating MCSs over the second-step terrain significantly impact the development and enhancement of moist convection and vortices in the downstream areas.展开更多
In this paper output predictive algorithm is applied to the design of predictive controller for an optimal path terrain following system. In this way, the error of path tracking is decreased to a minimum degree simply...In this paper output predictive algorithm is applied to the design of predictive controller for an optimal path terrain following system. In this way, the error of path tracking is decreased to a minimum degree simply and efficiently and the computation time for the optimal path is shortened greatly. Therefore, the real-time processing of the optimal path terrain following system is made to be very helpful.展开更多
With the acceleration of marine construction in China,the exploitation and utilization of resources from islands and reefs are necessary.To prevent and dissipate waves in the process of resource exploitation and utili...With the acceleration of marine construction in China,the exploitation and utilization of resources from islands and reefs are necessary.To prevent and dissipate waves in the process of resource exploitation and utilization,a more effective method is to install floating breakwaters near the terrain of islands and reefs.The terrain around islands and reefs is complex,and waves undergo a series of changes due to the impact of the complex terrain in transmission.It is important to find a suitable location for floating breakwater systems on islands and reefs and investigate how the terrain affects the system’s hydrodynamic performance.This paper introduces a three-cylinder floating breakwater design.The breakwater system consists of 8 units connected by elastic structures and secured by a slack mooring system.To evaluate its effectiveness,a 3D model experiment was conducted in a wave basin.During the experiment,a model resembling the islands and reefs terrain was created on the basis of the water depth map of a specific region in the East China Sea.The transmission coefficients and motion responses of the three-cylinder floating breakwater system were then measured.This was done both in the middle of and behind the islands and reefs terrain.According to the experimental results,the three-cylinder floating breakwater system performs better in terms of hydrodynamics when it is placed behind the terrain of islands and reefs than in the middle of the same terrain.展开更多
state space algorithms are proposed for the three degree of freedom (3DOF) optimal Wiener Hopf controller for a class of systems with time delay feedback sensors and employed in the design of a terrain following ...state space algorithms are proposed for the three degree of freedom (3DOF) optimal Wiener Hopf controller for a class of systems with time delay feedback sensors and employed in the design of a terrain following control system, with the influence caused by the delay of baric altimeter successfully eliminated.展开更多
An optimal preview method is applied to the design of terrain following controller for cruise missile. In this method, tracking errors and control increments are both considered in the quadratic cost function. Integra...An optimal preview method is applied to the design of terrain following controller for cruise missile. In this method, tracking errors and control increments are both considered in the quadratic cost function. Integrating the general optimal servo system with a preview feedforward compensation that feeds forward future command and future disturbance produces an optimal preview servo system. In the terrain following system, the flight altitude of the cruise missile is a command signal, and its future information can be known apriori. Hence, we have designed a terrain following controller with a basic state feedback and a feedforward compensation for future altitude information. Simulation results show that the performance of the terrain following system with such an optimal preview controller has been improved dramatically.展开更多
Unmanned aerial vehicle light detection and ranging(UAV–LiDAR)is a new method for collecting understory terrain data.The high estimation accuracy of understory terrain is crucial for accurate tree height measurement ...Unmanned aerial vehicle light detection and ranging(UAV–LiDAR)is a new method for collecting understory terrain data.The high estimation accuracy of understory terrain is crucial for accurate tree height measurement and forest resource surveys.The UAV–LiDAR flight altitude and forest canopy cover significantly impact the accuracy of understory terrain estimation.However,since no research examined their combined effects,we aimed to investigate this relationship.This will help optimize UAV–LiDAR flight parameters for understory terrain estimation and forest surveys across various canopy cover.This study analyzed the impacts of three flight altitudes and three canopy cover on the estimation accuracy of understory terrain.The results showed that when canopy cover exceeded a specific value,UAV–LiDAR flight altitudes significantly affected understory terrain estimation.Given a forest canopy cover,the reduction in ground point coverage increased significantly as the flight altitude increased;given a flight altitude,the higher the canopy cover,the more significant the reduction in ground point coverage.In forests with a canopy cover≥0.9,there were substantial differences in the accuracies of understory digital elevation models(DEMs)generated using UAV–LiDAR at different flight altitudes.For forests with a canopy cover<0.9,the mean absolute error(MAE)of understory DEMs from UAV–LiDAR at different flight altitudes was≤0.17 m and the root mean square error(RMSE)was≤0.24 m.However,for forests with a canopy cover≥0.9,the UAV–LiDAR flight altitude significantly affected the accuracy of understory DEMs.At the same flight altitude,the MAE and RMSE of the estimated elevation for forests with a canopy cover≥0.9 were approximately twice those of the estimated elevation for forests with a canopy cover<0.9.In forests with low canopy cover,it is possible to improve data collection efficiency by selecting a higher flight altitude.However,UAV–LiDAR flight altitudes significantly affected understory terrain estimation in forests with high canopy cover,it is essential to adopt terrain-following flight modes,reduce flight altitudes,and maintain a consistent flight altitude during longterm monitoring in high canopy cover forests.展开更多
Hilly terrain pipeline is a common form of pipeline in oil and gas storage and transportation industry.Due to the hilly terrain influence, the liquid at the elbow of the gathering pipeline is easy to flow back and acc...Hilly terrain pipeline is a common form of pipeline in oil and gas storage and transportation industry.Due to the hilly terrain influence, the liquid at the elbow of the gathering pipeline is easy to flow back and accumulate to form slug flow, so it is necessary to remove the accumulated liquid by gas purging. In this paper, experiment is carried out in hilly terrain pipelines. Three flow patterns of stratified flow, slug flow and stratified entrained flow are observed. The process of gas purging accumulated liquid is divided into four stages, namely liquid accumulation, liquid rising, continuous outflow and tail outflow. At the same time, the flow pattern maps of each stage are drawn. The pressure drop signal is analyzed in time domain and frequency domain, and the contour map of pressure drop distribution is drawn. It is found that the ratio of range to average value can well distinguish the occurrence range of each flow pattern.Based on visualization, the transition process of slug flow to stratified flow and stratified entrained flow is studied, and the transition boundary prediction model is established. An image processing method is proposed to convert the image signal into a similarity curve, and PSD analysis is performed to calculate the slug frequency. The normal distribution is used to fit the slug frequency, and the predicted correlation is in good agreement with the experimental data.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
In view of the airborne application characteristics such as flexible flight, large error of altimeter, large initial error of inertial navigation system, etc., a new terrain matching system architecture which is suita...In view of the airborne application characteristics such as flexible flight, large error of altimeter, large initial error of inertial navigation system, etc., a new terrain matching system architecture which is suitable for airborne application is presented. The key techniques in terrain matching system realizing process including system workflow, terrain matching algorithm and selection criterion of matching region are expatiated. The experimental results prove the rationality and feasibility of the proposed solution.展开更多
Accurate estimation of understory terrain has significant scientific importance for maintaining ecosystem balance and biodiversity conservation.Addressing the issue of inadequate representation of spatial heterogeneit...Accurate estimation of understory terrain has significant scientific importance for maintaining ecosystem balance and biodiversity conservation.Addressing the issue of inadequate representation of spatial heterogeneity when traditional forest topographic inversion methods consider the entire forest as the inversion unit,this study pro⁃poses a differentiated modeling approach to forest types based on refined land cover classification.Taking Puerto Ri⁃co and Maryland as study areas,a multi-dimensional feature system is constructed by integrating multi-source re⁃mote sensing data:ICESat-2 spaceborne LiDAR is used to obtain benchmark values for understory terrain,topo⁃graphic factors such as slope and aspect are extracted based on SRTM data,and vegetation cover characteristics are analyzed using Landsat-8 multispectral imagery.This study incorporates forest type as a classification modeling con⁃dition and applies the random forest algorithm to build differentiated topographic inversion models.Experimental re⁃sults indicate that,compared to traditional whole-area modeling methods(RMSE=5.06 m),forest type-based classi⁃fication modeling significantly improves the accuracy of understory terrain estimation(RMSE=2.94 m),validating the effectiveness of spatial heterogeneity modeling.Further sensitivity analysis reveals that canopy structure parame⁃ters(with RMSE variation reaching 4.11 m)exert a stronger regulatory effect on estimation accuracy compared to forest cover,providing important theoretical support for optimizing remote sensing models of forest topography.展开更多
The relevance of the work lies in its relation to the sustainability of mountain ecosystems of Kyrgyzstan in the context of growing tourist activity.The study area belongs to mountain ecosystems,which are highly sensi...The relevance of the work lies in its relation to the sustainability of mountain ecosystems of Kyrgyzstan in the context of growing tourist activity.The study area belongs to mountain ecosystems,which are highly sensitive to anthropogenic loads,and with the increase in this impact,the main tourism resources can be lost.The main objective of the work is to create a scientific basis for sustainable development of the studied region with minimal impact on the natural environment.The sustainability of the underlying surface was analyzed considering altitude,orography,climatic and seasonal changes,terrain slope,and other factors.Dominant plant species characteristic of different altitudinal levels were taken into account.An assessment of the level of degradation of the studied ecosystems was provided,based on field methods,by creating“transects,”which allow the identification of different levels of sustainability under anthropogenic influences.Based on the degree of degradation,the sites were ranked into six degrees of degradation.For this purpose,plant and soil samples were collected to assess the tourist load.To determine the potential for the development of tourist flows,their one-time throughput capacity was calculated,based on the total number in a specific area.Measures were proposed to regulate the flow of vacationers throughout the mountainous region.For these purposes,the maximum number of tourists per daily flow was determined.A methodology was developed for assessing mountain tourist zones,which is important for further regulation of the flow of vacationers,and will allow for the sustainable development of these zones in the future.展开更多
Background Three-dimensional terrain models are essential in domains such as video game development and film production.Because surface color is often correlated with terrain geometry,capturing this relationship is cr...Background Three-dimensional terrain models are essential in domains such as video game development and film production.Because surface color is often correlated with terrain geometry,capturing this relationship is critical for generating realistic results.However,most existing methods synthesize either a heightmap or a texture without adequately modeling their inherent correlation.Methods We propose a method that jointly generates terrain heightmaps and textures using a latent diffusion model.First,we train the model in an unsupervised manner to randomly generate paired heightmaps and textures.Then,we perform supervised learning on an external adapter to enable user control via hand-drawn sketches.Results Experiments demonstrate that our approach supports intuitive terrain generation while preserving the correlation between heightmaps and textures.Conclusion Our method outperforms the two-stage and GAN-based baselines by ensuring structural coherence,in which textures naturally align with geometry,successfully accommodating both realistic landscapes and extreme user-defined shapes.展开更多
The Light Detection and Ranging(LiDAR)data analysis method has emerged as a powerful and versatile tool for characterizing atmospheric conditions and modeling light propagation through various media.In the context of ...The Light Detection and Ranging(LiDAR)data analysis method has emerged as a powerful and versatile tool for characterizing atmospheric conditions and modeling light propagation through various media.In the context of renewable energy,particularly wind energy,LiDAR is increasingly utilized to analyze wind flow,turbine wake effects,and turbulence in complex terrains.This study focuses on advancing LiDAR data interpretation through the development and application of the LiDAR Statistical Barnes Objective Analysis(LiSBOA)method.LiSBOA enhances the capacity of scanning LiDAR systems by enabling more precise optimization of scan configurations and improving the retrieval of wind statistics across Cartesian grids.Unlike conventional approaches,LiSBOA offers fine-grained control over azimuthal resolution and spatial filtering,which allows for the detailed reconstruction of wind fields and turbulence structures.These capabilities are crucial for accurately simulating wind turbine wakes and power capture,particularly in environments with variable atmospheric stability and complex topography.Field deployments and comparative assessments against traditional meteorological mast data demonstrate the effectiveness of LiSBOA.The method reduces wind velocity estimation errors to within 3%and increases the accuracy of turbulence intensity measurements by over 4%.Such improvements are significant for enhancing wind resource assessment,optimizing turbine placement,and refining control strategies for operational turbines.LiSBOA represents a robust advancement in LiDAR data processing for wind energy applications.By addressing limitations in spatial resolution and measurement uncertainty,it supports more reliable modeling of wake interactions and flow variability.This work contributes to improving the efficiency and reliability of wind energy systems through advanced remote sensing and statistical analysis techniques.展开更多
Agricultural terraces are significant for food provision,environmental stability and sustainable resource management.However,the spatiotemporal evolution of terraces and their influence on food productivity in mountai...Agricultural terraces are significant for food provision,environmental stability and sustainable resource management.However,the spatiotemporal evolution of terraces and their influence on food productivity in mountainous landscapes remain poorly understood.Taking the Chinese Loess Plateau(LP)as an example,this study conducted multitemporal mapping of terraces and sloping croplands over three decades(1990-2020),systematically assessing their impacts on food output through terrain gradient analysis.The results indicated that:(1)the terraced area expanded in the past 30 years,particularly across steeper terrain gradients(third to fifth gradients);(2)sloping croplands predominantly occupied gentle slopes(first to second gradients),exhibiting area reduction correlating with urbanization processes;(3)the food provision increased extensively,with yield decreasing from southeast to northwest and regions of high yielding mainly in terraced fields;(4)over time,the variation of food provision correlated positively with the area of sloping cropland at low gradients,while at higher gradients,the expansion of terraces dominated the increase in food provision;(5)spatial clustering analysis revealed significant food productivity associated with high-density terrace distribution across steeper slope gradients.Low yields could be attributed to improper terrace management.This study clarified the impact of long-term terrace patterns on food provision and offered large-scale perspectives for terrace-based agriculture to enhance food security.Furthermore,the findings underscore the imperative of integrated land management in topographically complex regions,informing evidence-based policymaking for rational allocation and optimal utilization of terrace resources.展开更多
文摘Shallow landslides are strongly controlled by near-surface lithological variability,yet conventional geological maps are often too generalized to support accurate susceptibility assessment in complex terrains.This review synthesizes recent advances in remote sensing–based lithological mapping and evaluates their integration into landslide susceptibility modeling.Evidence from the literature indicates that remote sensing-derived lithological products,particularly those incorporating mineralogical information and higher spatial resolution,consistently outperform traditional geological maps in improving model accuracy and spatial detail,especially in heterogeneous environments.However,key challenges remain,including scale mismatches between surface observations and subsurface controls,limited ground validation,uncertainty propagation,and restricted model transferability across regions.The review identifies multi-sensor data fusion and explainable machine learning as the most promising directions for advancing lithological discrimination and model reliability.Future progress depends on integrating remote sensing with process-based understanding,improving validation strategies,and standardizing uncertainty reporting.These developments are essential for enabling more robust,scalable,and operationally relevant landslide susceptibility assessments in complex terrains.Lastly,we describe the directions of research that focus on multi-sensor fusion,explainable machine learning,UAV(Unmanned Aerial Vehicle)-enabled validation,and standardized uncertainty reporting that can help articulate landslide susceptibility assessment,making them even more robust and operationally significant.
基金supported by the National Key Research and Development Program(No.2022YFC2807400)the National Natural Science Foundation of China(Nos.12265003 and 12205044)。
文摘Aerial surveys are dynamic and continuous processes,and there are different height distributions of the ground in the measurement area,which leads to problems such as overlapping measurement areas and inaccurate altitude correction during the survey process.Commonly used terrain correction methods are based on the concept of finite elementization of ground surface radioactive sources,using GPS coordinates,radar altitude,and ground elevation distribution information from aerial surveys,combined with the sourceless efficiency calibration method to construct a response matrix,which is then inverted for surface nuclide content.However,most of the sourceless efficiency calibration methods used are numerical calculations that consider the body detector as a point detector and do not consider the changes in intrinsic detection efficiency under different incident directions of gamma rays.Therefore,when the altitude of the measurement area varies significantly or the flight altitude of the aerial survey is relatively low,such sourceless efficiency calibration method calculations tend to have a large bias,which affects the accuracy of the terrain correction.To address the above problems,this study employs a novel sourceless efficiency calibration method based on the Boolean operation of the ray deposition process and simplifies the traditional body source measurement model to a surface source measurement model to achieve fast and accurate efficiency calibration.Then,through the discretization of the measurement process,the static measurement process is superposed as equivalent to the dynamic measurement process,and the dynamic measurement response matrix is built and optimized based on the calibration method.Finally,the PSO-MLEM algorithm was used to solve the dynamic measurement response matrix to achieve dynamic terrain correction of aerial survey data.Analysis of the Baiyun'ebo test area revealed that,after applying dynamic terrain correction,the inverted anomalies in uranium(eU),thorium(eTh),and potassium(K)concentrations were closer to ground measurements(within 5.72%-30.79%)and exhibited clearer anomaly boundaries compared to traditional height-based corrections.However,owing to the inherent statistical fluctuations and characteristics of matrix inversion,higher measurement values tend to absorb lower ones,potentially enlarging the anomalous regions.Nevertheless,the highanomaly regions after inversion largely coincided with the ground truth validation,demonstrating that the proposed method can effectively correct airborne gamma spectrometry data.
文摘In 2025,I had the honor of delivering keynote speeches at the conferences of the International Society for Diet and Activity Methods in Toronto,Canada,and the International Society of Behavioural Nutrition and Physical Activity in Auckland,Aotearoa,New Zealand.These opportunities prompted deep reflection on scientific research in general,and on physical activity and health research specifically.
基金Pre-Research Program of General Armament Department during the11th Five-Year Plan Period (No51309020503)the National Defense Basic Research Program of China (973Program)(No973-61334)+1 种基金the National Natural Science Foundation of China(No50575042)Specialized Research Fund for the Doctoral Program of Higher Education (No20050286026)
文摘To improve the navigation accuracy of an autonomous underwater vehicle （AUV）, a novel terrain passive integrated navigation system （TPINS） is presented. According to the characteristics of the underwater environment and AUV navigation requirements of low cost and high accuracy, a novel TPINS is designed with a configuration of the strapdown inertial navigation system （SINS）, the terrain reference navigation system （TRNS）, the Doppler velocity sonar （DVS）, the magnetic compass and the navigation computer utilizing the unscented Kalman filter （UKF） to fuse the navigation information from various navigation sensors. Linear filter equations for the extended Kalman filter （EKF）, nonlinear filter equations for the UKF and measurement equations of navigation sensors are addressed. It is indicated from the comparable simulation experiments of the EKF and the UKF that AUV navigation precision is improved substantially with the proposed sensors and the UKF when compared to the EKF. The TPINS designed with the proposed sensors and the UKF is effective in reducing AUV navigation position errors and improving the stability and precision of the AUV underwater integrated navigation.
基金National Public Benefit Research Foundation of China (2008416048GYHY201006035)
文摘The results from a hybrid approach that combines a mesoscale meteorological model with a diagnostic model to produce high-resolution wind fields in complex coastal topography are evaluated.The diagnostic wind model(California Meteorological Model,CALMET) with 100-m horizontal spacing was driven with outputs from the Weather Research and Forecasting(WRF) model to obtain near-surface winds for the 1-year period from 12 September 2003 to 11 September 2004.Results were compared with wind observations at four sites.Traditional statistical scores,including correlation coefficients,standard deviations(SDs) and mean absolute errors(MAEs),indicate that the wind estimates from the WRF/CALMET modeling system are produced reasonably well.The correlation coefficients are relatively large,ranging from 0.5 to 0.7 for the zonal wind component and from 0.75 to 0.85 for the meridional wind component.MAEs for wind speed range from 1.5 to 2.0 m s-1 at 10 meters above ground level(AGL) and from 2.0 to 2.5 m s-1 at 60 m AGL.MAEs for wind direction range from 30 to 40 degrees at both levels.A spectral decomposition of the time series of wind speed shows positive impacts of CALMET in improving the mesoscale winds.Moreover,combining the CALMET model with WRF significantly improves the spatial variability of the simulated wind fields.It can be concluded that the WRF/CALMET modeling system is capable of providing a detailed near-surface wind field,but the physics in the diagnostic CALMET model needs to be further improved.
基金supported by National Natural Science Foundation of China(Grant No.50975059,Grant No.61005080)Postdoctoral Foundation of China(Grant No.20100480994)+1 种基金Postdoctoral Foundation of Heilongjiang Province,Foundation of Chinese State Key Laboratory of Robotics and Systems(Grant No.SKLRS200801A02)College Discipline Innovation Wisdom Plan of China(111 Project,Grant No.B07018)
文摘Virtual simulation technology is of great importance for the teleoperation of lunar rovers during the exploration phase,as well as the design of locomotion systems,performance evaluation,and control strategy verification during the R&D phase.The currently used simulation methods for lunar rovers have several disadvantages such as poor fidelity for wheel-soil interaction mechanics,difficulty in simulating rough terrains,and high complexity making it difficult to realize mobility control in simulation systems.This paper presents an approach for the construction of a virtual simulation system that integrates the features of 3D modeling,wheel-soil interaction mechanics,dynamics analysis,mobility control,and visualization for lunar rovers.Wheel-soil interaction experiments are carried out to test the forces and moments acted on a lunar rover’s wheel by the soil with a vertical load of 80 N and slip ratios of 0,0.03,0.05,0.1,0.2,0.3,0.4,and 0.6.The experimental results are referenced in order to set the parameters’values for the PAC2002 tire model of the ADAMS/Tire module.In addition,the rough lunar terrain is simulated with 3DS Max software after analyzing its characteristics,and a data-transfer program is developed with Matlab to simulate the 3D reappearance of a lunar environment in ADAMS.The 3D model of a lunar rover is developed by using Pro/E software and is then imported into ADAMS.Finally,a virtual simulation system for lunar rovers is developed.A path-following control strategy based on slip compensation for a six-wheeled lunar rover prototype is researched.The controller is implemented by using Matlab/Simulink to carry out joint simulations with ADAMS.The designed virtual lunar rover could follow the planned path on a rough terrain.This paper can also provide a reference scheme for virtual simulation and performance analysis of rovers moving on rough lunar terrains.
基金supported by the National Key R&D Program of China(Grant No.2018YFC1507200)the National Natural Science Foundation of China(Grant No.41975057).
文摘Based on the previous statistical analysis of mesoscale convective systems(MCSs)over the second-step terrain along Yangtze-Huaihe River Valley,eight representative long-lived eastward-propagating MCSs are selected for model-based sensitivity testing to investigate the initiation and evolution of these types of MCSs as well as their impact on downstream areas.We subject each MCS to a semi-idealized(CNTL)simulation and a sensitivity(NOLH)simulation that neglects condensational heating in the formation region.The CNTL experiment reveals convection forms in the region downstream of a shortwave trough typified by persistent southwesterly winds in the low-to midtroposphere.Upon merging with other convective systems,moist convection develops into an MCS,which propagates eastward under the influence of mid-tropospheric westerlies,and moves out of the second-step terrain.The MCS then merges with pre-existing local convection over the plains;the merged convection reinforces the cyclonic wind perturbation into a mesoscale vortex at 850 hPa.While this vortex moves eastward to regions with local vortex at 850 hPa,another vortex at 925 hPa is also intensified.Finally,the vortices at 850 and 925 hPa merge together and develop into a mesoscale convective vortex(MCV).In contrast,MCSs fail to form and move eastward in the NOLH experiment.In the absence of eastward-propagating MCSs,moist convection and mesoscale vortices still appear in the plains,but the vortex strength and precipitation intensity are significantly weakened.It is suggested the eastward-propagating MCSs over the second-step terrain significantly impact the development and enhancement of moist convection and vortices in the downstream areas.
文摘In this paper output predictive algorithm is applied to the design of predictive controller for an optimal path terrain following system. In this way, the error of path tracking is decreased to a minimum degree simply and efficiently and the computation time for the optimal path is shortened greatly. Therefore, the real-time processing of the optimal path terrain following system is made to be very helpful.
基金financially supported by the China National Funds for Distinguished Young Scientists(Grant No.52025112).
文摘With the acceleration of marine construction in China,the exploitation and utilization of resources from islands and reefs are necessary.To prevent and dissipate waves in the process of resource exploitation and utilization,a more effective method is to install floating breakwaters near the terrain of islands and reefs.The terrain around islands and reefs is complex,and waves undergo a series of changes due to the impact of the complex terrain in transmission.It is important to find a suitable location for floating breakwater systems on islands and reefs and investigate how the terrain affects the system’s hydrodynamic performance.This paper introduces a three-cylinder floating breakwater design.The breakwater system consists of 8 units connected by elastic structures and secured by a slack mooring system.To evaluate its effectiveness,a 3D model experiment was conducted in a wave basin.During the experiment,a model resembling the islands and reefs terrain was created on the basis of the water depth map of a specific region in the East China Sea.The transmission coefficients and motion responses of the three-cylinder floating breakwater system were then measured.This was done both in the middle of and behind the islands and reefs terrain.According to the experimental results,the three-cylinder floating breakwater system performs better in terms of hydrodynamics when it is placed behind the terrain of islands and reefs than in the middle of the same terrain.
文摘state space algorithms are proposed for the three degree of freedom (3DOF) optimal Wiener Hopf controller for a class of systems with time delay feedback sensors and employed in the design of a terrain following control system, with the influence caused by the delay of baric altimeter successfully eliminated.
文摘An optimal preview method is applied to the design of terrain following controller for cruise missile. In this method, tracking errors and control increments are both considered in the quadratic cost function. Integrating the general optimal servo system with a preview feedforward compensation that feeds forward future command and future disturbance produces an optimal preview servo system. In the terrain following system, the flight altitude of the cruise missile is a command signal, and its future information can be known apriori. Hence, we have designed a terrain following controller with a basic state feedback and a feedforward compensation for future altitude information. Simulation results show that the performance of the terrain following system with such an optimal preview controller has been improved dramatically.
基金supported by the National Natural Science Foundation of China(No.32271876)the Research on Key Technologies of Intelligent Monitoring and Carbon Sink Metering of Forest Resources in Fujian Province(No.2022FKJ03)the Science and Technology Innovation Project of Fujian Agriculture and Forestry University(No.KFB23172A,KFB23173A).
文摘Unmanned aerial vehicle light detection and ranging(UAV–LiDAR)is a new method for collecting understory terrain data.The high estimation accuracy of understory terrain is crucial for accurate tree height measurement and forest resource surveys.The UAV–LiDAR flight altitude and forest canopy cover significantly impact the accuracy of understory terrain estimation.However,since no research examined their combined effects,we aimed to investigate this relationship.This will help optimize UAV–LiDAR flight parameters for understory terrain estimation and forest surveys across various canopy cover.This study analyzed the impacts of three flight altitudes and three canopy cover on the estimation accuracy of understory terrain.The results showed that when canopy cover exceeded a specific value,UAV–LiDAR flight altitudes significantly affected understory terrain estimation.Given a forest canopy cover,the reduction in ground point coverage increased significantly as the flight altitude increased;given a flight altitude,the higher the canopy cover,the more significant the reduction in ground point coverage.In forests with a canopy cover≥0.9,there were substantial differences in the accuracies of understory digital elevation models(DEMs)generated using UAV–LiDAR at different flight altitudes.For forests with a canopy cover<0.9,the mean absolute error(MAE)of understory DEMs from UAV–LiDAR at different flight altitudes was≤0.17 m and the root mean square error(RMSE)was≤0.24 m.However,for forests with a canopy cover≥0.9,the UAV–LiDAR flight altitude significantly affected the accuracy of understory DEMs.At the same flight altitude,the MAE and RMSE of the estimated elevation for forests with a canopy cover≥0.9 were approximately twice those of the estimated elevation for forests with a canopy cover<0.9.In forests with low canopy cover,it is possible to improve data collection efficiency by selecting a higher flight altitude.However,UAV–LiDAR flight altitudes significantly affected understory terrain estimation in forests with high canopy cover,it is essential to adopt terrain-following flight modes,reduce flight altitudes,and maintain a consistent flight altitude during longterm monitoring in high canopy cover forests.
基金supported by the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(No.52488201)the National Natural Science Foundation of China(No.52422606).
文摘Hilly terrain pipeline is a common form of pipeline in oil and gas storage and transportation industry.Due to the hilly terrain influence, the liquid at the elbow of the gathering pipeline is easy to flow back and accumulate to form slug flow, so it is necessary to remove the accumulated liquid by gas purging. In this paper, experiment is carried out in hilly terrain pipelines. Three flow patterns of stratified flow, slug flow and stratified entrained flow are observed. The process of gas purging accumulated liquid is divided into four stages, namely liquid accumulation, liquid rising, continuous outflow and tail outflow. At the same time, the flow pattern maps of each stage are drawn. The pressure drop signal is analyzed in time domain and frequency domain, and the contour map of pressure drop distribution is drawn. It is found that the ratio of range to average value can well distinguish the occurrence range of each flow pattern.Based on visualization, the transition process of slug flow to stratified flow and stratified entrained flow is studied, and the transition boundary prediction model is established. An image processing method is proposed to convert the image signal into a similarity curve, and PSD analysis is performed to calculate the slug frequency. The normal distribution is used to fit the slug frequency, and the predicted correlation is in good agreement with the experimental data.
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This work was supported by the National Key Basic Research and Development （973） Program of China （Grant No. 2010CB731806） and Aeronautical Science Foundation of China （Grant No. 20100818018）.
文摘In view of the airborne application characteristics such as flexible flight, large error of altimeter, large initial error of inertial navigation system, etc., a new terrain matching system architecture which is suitable for airborne application is presented. The key techniques in terrain matching system realizing process including system workflow, terrain matching algorithm and selection criterion of matching region are expatiated. The experimental results prove the rationality and feasibility of the proposed solution.
基金Supported by the National Natural Science Foundation of China(42401488,42071351)the National Key Research and Development Program of China(2020YFA0608501,2017YFB0504204)+4 种基金the Liaoning Revitalization Talents Program(XLYC1802027)the Talent Recruited Program of the Chinese Academy of Science(Y938091)the Project Supported Discipline Innovation Team of the Liaoning Technical University(LNTU20TD-23)the Liaoning Province Doctoral Research Initiation Fund Program(2023-BS-202)the Basic Research Projects of Liaoning Department of Education(JYTQN2023202)。
文摘Accurate estimation of understory terrain has significant scientific importance for maintaining ecosystem balance and biodiversity conservation.Addressing the issue of inadequate representation of spatial heterogeneity when traditional forest topographic inversion methods consider the entire forest as the inversion unit,this study pro⁃poses a differentiated modeling approach to forest types based on refined land cover classification.Taking Puerto Ri⁃co and Maryland as study areas,a multi-dimensional feature system is constructed by integrating multi-source re⁃mote sensing data:ICESat-2 spaceborne LiDAR is used to obtain benchmark values for understory terrain,topo⁃graphic factors such as slope and aspect are extracted based on SRTM data,and vegetation cover characteristics are analyzed using Landsat-8 multispectral imagery.This study incorporates forest type as a classification modeling con⁃dition and applies the random forest algorithm to build differentiated topographic inversion models.Experimental re⁃sults indicate that,compared to traditional whole-area modeling methods(RMSE=5.06 m),forest type-based classi⁃fication modeling significantly improves the accuracy of understory terrain estimation(RMSE=2.94 m),validating the effectiveness of spatial heterogeneity modeling.Further sensitivity analysis reveals that canopy structure parame⁃ters(with RMSE variation reaching 4.11 m)exert a stronger regulatory effect on estimation accuracy compared to forest cover,providing important theoretical support for optimizing remote sensing models of forest topography.
文摘The relevance of the work lies in its relation to the sustainability of mountain ecosystems of Kyrgyzstan in the context of growing tourist activity.The study area belongs to mountain ecosystems,which are highly sensitive to anthropogenic loads,and with the increase in this impact,the main tourism resources can be lost.The main objective of the work is to create a scientific basis for sustainable development of the studied region with minimal impact on the natural environment.The sustainability of the underlying surface was analyzed considering altitude,orography,climatic and seasonal changes,terrain slope,and other factors.Dominant plant species characteristic of different altitudinal levels were taken into account.An assessment of the level of degradation of the studied ecosystems was provided,based on field methods,by creating“transects,”which allow the identification of different levels of sustainability under anthropogenic influences.Based on the degree of degradation,the sites were ranked into six degrees of degradation.For this purpose,plant and soil samples were collected to assess the tourist load.To determine the potential for the development of tourist flows,their one-time throughput capacity was calculated,based on the total number in a specific area.Measures were proposed to regulate the flow of vacationers throughout the mountainous region.For these purposes,the maximum number of tourists per daily flow was determined.A methodology was developed for assessing mountain tourist zones,which is important for further regulation of the flow of vacationers,and will allow for the sustainable development of these zones in the future.
文摘Background Three-dimensional terrain models are essential in domains such as video game development and film production.Because surface color is often correlated with terrain geometry,capturing this relationship is critical for generating realistic results.However,most existing methods synthesize either a heightmap or a texture without adequately modeling their inherent correlation.Methods We propose a method that jointly generates terrain heightmaps and textures using a latent diffusion model.First,we train the model in an unsupervised manner to randomly generate paired heightmaps and textures.Then,we perform supervised learning on an external adapter to enable user control via hand-drawn sketches.Results Experiments demonstrate that our approach supports intuitive terrain generation while preserving the correlation between heightmaps and textures.Conclusion Our method outperforms the two-stage and GAN-based baselines by ensuring structural coherence,in which textures naturally align with geometry,successfully accommodating both realistic landscapes and extreme user-defined shapes.
文摘The Light Detection and Ranging(LiDAR)data analysis method has emerged as a powerful and versatile tool for characterizing atmospheric conditions and modeling light propagation through various media.In the context of renewable energy,particularly wind energy,LiDAR is increasingly utilized to analyze wind flow,turbine wake effects,and turbulence in complex terrains.This study focuses on advancing LiDAR data interpretation through the development and application of the LiDAR Statistical Barnes Objective Analysis(LiSBOA)method.LiSBOA enhances the capacity of scanning LiDAR systems by enabling more precise optimization of scan configurations and improving the retrieval of wind statistics across Cartesian grids.Unlike conventional approaches,LiSBOA offers fine-grained control over azimuthal resolution and spatial filtering,which allows for the detailed reconstruction of wind fields and turbulence structures.These capabilities are crucial for accurately simulating wind turbine wakes and power capture,particularly in environments with variable atmospheric stability and complex topography.Field deployments and comparative assessments against traditional meteorological mast data demonstrate the effectiveness of LiSBOA.The method reduces wind velocity estimation errors to within 3%and increases the accuracy of turbulence intensity measurements by over 4%.Such improvements are significant for enhancing wind resource assessment,optimizing turbine placement,and refining control strategies for operational turbines.LiSBOA represents a robust advancement in LiDAR data processing for wind energy applications.By addressing limitations in spatial resolution and measurement uncertainty,it supports more reliable modeling of wake interactions and flow variability.This work contributes to improving the efficiency and reliability of wind energy systems through advanced remote sensing and statistical analysis techniques.
基金supported by the National Natural Science Foundation of China(Grants No.U21A2011,41971129)the National Key Research and Development Program of China(Grant No.2022YFF1300403)the Distinguished Membership Project of the Youth Innovation Promotion Association of CAS(Grant No.Y201812)。
文摘Agricultural terraces are significant for food provision,environmental stability and sustainable resource management.However,the spatiotemporal evolution of terraces and their influence on food productivity in mountainous landscapes remain poorly understood.Taking the Chinese Loess Plateau(LP)as an example,this study conducted multitemporal mapping of terraces and sloping croplands over three decades(1990-2020),systematically assessing their impacts on food output through terrain gradient analysis.The results indicated that:(1)the terraced area expanded in the past 30 years,particularly across steeper terrain gradients(third to fifth gradients);(2)sloping croplands predominantly occupied gentle slopes(first to second gradients),exhibiting area reduction correlating with urbanization processes;(3)the food provision increased extensively,with yield decreasing from southeast to northwest and regions of high yielding mainly in terraced fields;(4)over time,the variation of food provision correlated positively with the area of sloping cropland at low gradients,while at higher gradients,the expansion of terraces dominated the increase in food provision;(5)spatial clustering analysis revealed significant food productivity associated with high-density terrace distribution across steeper slope gradients.Low yields could be attributed to improper terrace management.This study clarified the impact of long-term terrace patterns on food provision and offered large-scale perspectives for terrace-based agriculture to enhance food security.Furthermore,the findings underscore the imperative of integrated land management in topographically complex regions,informing evidence-based policymaking for rational allocation and optimal utilization of terrace resources.
