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In this paper, the application is investigated of fast Fourier transform filtering (FFT-FR) to high spatial resolution digital terrain models (HR-DTM) derived from LiDAR sensors, assessing its efficacy in identifying genuine relief elements, including both natural geological features and anthropogenic landforms. The suitability of the derived filtered geomorphic references (FGRs) is evaluated through spatial correlation with ground truths (GTs) extracted from the topographical and geological geodatabases of Santander Bay, Northern Spain. In this study, it is revealed that existing artefacts, derived from vegetation or human infrastructures, pose challenges in the units' construction, and large physiographic units are better represented using low-pass filters, whereas detailed units are more accurately depicted with high-pass filters. The results indicate a propensity of high-frequency filters to detect anthropogenic elements within the DTM. The quality of GTs used for validation proves more critical than the geodatabase scale. Additionally, in this study, it is demonstrated that the footprint of buildings remains uneliminated, indicating that the model is a poorly refined digital surface model (DSM) rather than a true digital terrain model (DTM). Experiments validate the DTM's capability to highlight contacts and constructions, with water detection showing high precision (≥60%) and varying precision for buildings. Large units are better captured with low filters, whilst high filters effectively detect anthropogenic elements and more detailed units. This facilitates the design of validation and correction procedures for DEMs derived from LiDAR point clouds, enhancing the potential for more accurate and objective Earth surface representation. [ABSTRACT FROM AUTHOR]

In hydrogeology, equations describing exchange flux in sedimentary systems mainly focus on the geometry of the streambed–aquifer system and parameters. However, groundwater flow in fractured crystalline basement and volcanic rocks, which are mainly characterized by restricted flow, receives little attention in groundwater flow equations, possibly due to a lack of appropriate data. This study develops an analytical equation to estimate groundwater inflow into mine pits in volcanic rock, addressing a significant knowledge gap in the literature. The equation was validated through a case study evaluation at the Nsuta Mine, where it accurately estimated groundwater inflow into the pit. Results indicate that estimated inflow at the current pit floor level (−60 MSL) is 38 710 m3/day, which is close to the actual dewatering rate of 39 794 m3/day (error percentage of 2.8%). The study also projects groundwater inflow at a deeper pit level (−200 MSL) to be 82 400 m3/day with a corresponding flux of 0.331 m/day. [ABSTRACT FROM AUTHOR]

Semi-numerical methods hold significant value due to their efficiency in time-consuming calculations. Accordingly, this article proposes an effective strategy to derive the vibration parameters of cylindrical shells (CSs) with cutout utilizing a semi-analytical approach entitled differential transform method (DTM). To achieve this, the governing equations of motion are first introduced based on Sander's theory of shells. These equations give rise to a coupled system of linear ordinary differential equations, which pose a challenge in solving the eigenvalue problem. It should be emphasized that the classical version of the differential transform method could not be directly applied to solve the eigenvalue problem related to the above-mentioned coupled differential equation. An innovative technique is employed and discussed in the paper to remedy these difficulties, which could be widely used in similar problems. As a result, the natural frequencies and mode shapes of some CSs with cutouts, various internal angles, and diverse material characteristics are attained. The outcomes undergo validation through the hybrid finite element method, and the proposed method's accuracy is rigorously proved. In conclusion, the proposed DTM provides an efficient solution to the eigenvalue problem of coupled differential equations and offers a valuable tool for obtaining accurate vibration parameters of CSs. [ABSTRACT FROM AUTHOR]

Improving machinability of various difficult-to-cut materials has become essential in recent years. Out of several parameters, enhancing the delivery method of cutting fluids enhances machinability. Several researchers have previously found that utilising the Minimum Quantity Lubrication technique for cutting fluid delivery has had beneficial effects. Nevertheless, a significantly persisting problem is the ineffective penetration of cutting fluid in certain zones in the chip-tool interface. Microchannel fabrication on cutting tools may help cutting fluids penetrate the chip-tool heat generation zone effectively. However, micro-channelling may also increase the stress concentration on the cutting tool, thus it may promote catastrophic failure. This article aims to discuss the effect of creating a single microchannel on tool rake surfaces to improve the penetrability of the cutting fluid while also determining the change in the tool’s stability. Diversifying the shape of the microchannel by keeping its width unwavering, and changing its nearness from the principle cutting edge, simulations were performed. Further investigations reveal that incorporating microchannels can have a positive impact on cutting fluid delivery without sabotaging the tool’s strength. This inadvertently may help in effective cooling, lubrication and protection of the cutting tool. [ABSTRACT FROM AUTHOR]

The Troesch problem is a well-known and important problem; the ability to solve it is important due to the practical applications of this problem. In this paper, we propose a method to solve this problem using a combination of two useful algorithms: Different Transform Method (DTM) and Adomian Decomposition Method (ADM). The combination of these two methods resulted in a continuous approximate solution to this problem and eliminated the problems that occur when trying to use each of these methods separately. The great advantages of the DTM method are the continuous form of the solution and the fact that it easy to implement error control. However, in too-complex tasks, this method becomes difficult to use. By using a hybrid of ADM and DTM, we obtain a relatively simple-to-implement method that retains the advantages of the DTM approach. [ABSTRACT FROM AUTHOR]

Based on the two-dimensional resistive magnetohydrodynamics (MHD) model, this study explores the impact of shear flow on the resonant magnetic perturbation (RMP)-induced double tearing mode (DTM). The results indicate that the effectiveness of shear flow in suppressing the double tearing mode is primarily dependent on the flow velocity at the outer rational surface. A notable finding is that, with higher flow velocities, the double tearing mode is effectively suppressed. However, in cases of very weak flow velocities, the shear flow still exerts an influence, but with a limited suppression effect. Specifically, it can only inhibit the inner island, while the outer island continues to grow under the influence of the resonant magnetic perturbation. [ABSTRACT FROM AUTHOR]

The aim of the paper is to describe an integrated methodological approach of photogrammetric survey from UAVs (Unmanned Aerial Vehicles) that can be used in the field of engineering planning and design. In particular, a process is described in which the outputs from photogrammetric processing are implemented in different analysis or 3D modelling platforms to support all design activities in the field of engineering and in particular in the field of civil and environmental design. This approach was applied to an area of considerable landscape-environmental interest characterised by the presence of an estuary and a masonry bridge. The outputs of the photogrammetric processing have therefore constituted a valid support at cartographic level and for the production of two-dimensional CAD (Computer-Aided Design) drawings, as well as in the design of a cycle path, in the assessment of hydraulic risk or in the BIM (Building Information Modeling) design of the road infrastructure. The adopted methodology made it possible to obtain a high-performance and geometrically accurate dataset, characterised by high resolution, quickly and with low investment costs. In addition, by using UAV platforms, it was possible to reach inaccessible areas, limiting the risk of the operators specialised in surveying and optimising the time of operations, while still guaranteeing a complete product without loss of information necessary for BIM, GIS (Geographical Information System) and CAD procedures. [ABSTRACT FROM AUTHOR]

Quantitative research on the evolution and transformation of topics in China's energy policy can enhance the theoretical and methodological framework of policy document analysis. Utilizing dynamic topic modeling (DTM) and social network analysis, this study examined 1872 energy policy documents issued in China between 1980 and 2023, focusing on detecting hot topics and analyzing trend evolution. DTM identified five core topics: State Grid and new energy, comprehensive energy conservation and emission reduction, intelligent building energy management, promotion of energy-saving products and new energy vehicles, and standardization of energy industry management. Temporal analysis of these core topics reveals a shift in policy focus over time, moving from infrastructure development and standardization management to new energy development and modernization of the energy system. The co-occurrence network of thematic terms transitions from an "independent and loose" structure to a "concentrated and balanced" one, with increasing network scale and frequency. The conclusions of this study offer valuable insights for establishing a dynamic monitoring and real-time updating mechanism for energy policies, enhancing the integration and coordination of energy policy topics, and effectively supporting national energy strategies in response to global energy market challenges. [ABSTRACT FROM AUTHOR]

Due to the numerous practices of non-Newtonian fluids in technological and industrial fields, the attention towards such fluids increases incredibly. The highly nonlinear equations emerge in the modeling of the non-Newtonian fluids. The differential transform method is one of the analytical methods which is used to acquire the solution to these complicated nonlinear equations in the series form. The current analysis comprises the squeeze flow of non-Newtonian fluid in two dimensions. Two infinite parallel plates are considered in which the time-dependent fluid is squeezed. The heat transfer mechanism is deliberated with the significance of heat absorption/generation. The nonlinear setup of ordinary differential equations is acquired by practicing the appropriate similarity variables on the governing equations of the concerned flow mechanism. The nonlinear setup is analytically resolved with the help of an analytical differential transform method. For the authenticity of the differential transform method, the analytical outcomes are compared with the numerical results. Graphical illustrations of fluid temperature and velocity profiles relative to the pertinent parameters are briefly explicated numerically and analytically. The fluid velocity demonstrates the descending behavior and the temperature field exhibits the expanding nature relative to the squeezing parameter. [ABSTRACT FROM AUTHOR]

In this paper, solutions of some differential equations are found using alpha parametrized differential transform method (α-PDTM). The results are compared with the exact solution and the results found from the classical differential transform method (DTM). The optimal values of a are found for which the error at some particular domain point is minimal. It is found that the alpha parametrized differential transform method is more accurate and precise method. [ABSTRACT FROM AUTHOR]

This work presents the possibilities of joint use of UAV and GIS in the study of morphodynamical processes. A comparison of the results of direct field measurements with remote sensing using UAV is presented here. Point clouds and DTMs were studied to establish the degree of reliability of remote sensing when comparing periodically collected data and the terrain changes, they reflect. The goal is to prepare a working model that can be useful for scientific research and monitoring of infrastructure facilities. [ABSTRACT FROM AUTHOR]

Drawing on data from 133 Chinese New Energy Vehicle (NEV) policy documents from 2007 to 2023, this study utilizes Dynamic Topic Modelling (DTM), social network analysis and a quantitative model to investigate the evolutionary path of policy themes and the coordination effects. The following results were obtained. (1) A thematic cross-sectional analysis identified six core policy themes, namely, coordinated promotion of technology and finance, industry development and safety standardisation, market service and technical support systems, promotion strategy and urban cluster development, industrial capital and safety supervision mechanisms, and policy support and market expansion. The analysis also mapped the distribution of hot spots within these themes. (2) The keyword co-occurrence network of the NEV policy indicated that the network structure evolved from an initial 'overall dispersion–theme concentration', comprising 16 policy themes, to an 'overall stability–theme coordination', consisting of 14 policy themes. (3) The coordination degrees across the three types of policies exhibited a consistent upward spiral, with the comprehensive coordination index surging from 30 in 2007 to 951 in 2023, underscoring the complementary effects among policy instruments. These conclusions offer valuable insights for government departments to understand NEV development trends and dynamically adjust policy themes accordingly. [ABSTRACT FROM AUTHOR]

Copyright of Mesopotamian Journal of CyberSecurity is the property of Mesopotamian Academic Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coatings & Protection / Tuceng yu Fanghu is the property of Coating & Protection Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The thermoelastic time-dependent creep progress of a rotating annular plate with nonuniform thickness made of functionally graded piezoelectric material considering convection heat transfer and solar radiation was investigated. The nonlinear differential equation of heat transfer considering conduction, convection, and solar radiation was solved using the differential transformation method. Then, the differential equation of equilibrium for the annular plate containing creep strains was derived. Firstly, the differential equation was solved analytically for the zero time. Then, the stress and strain rates were achieved using Norton's law with Prandtl–Reuss equations. Finally, the time-dependent creep stresses and deformation redistributions were obtained employing an iterative method. [ABSTRACT FROM AUTHOR]

The Malé Karpaty Mountains in southwestern Slovakia contain more than 650 dolines, mostly arranged along tectonic and lithological boundaries. These dolines serve as important indicators of geological structures and provide valuable insights into the underlying bedrock and rock formations. This study focuses on the spatial distribution and formation processes of dolines in the Malé Karpaty Mts. using advanced methods, such as Digital Terrain Models (DTM) derived from airborne LiDAR data. By combining DTM with field measurements and GIS analysis, the study identifies the tectonic and lithological controls on doline formation and demonstrates their value in interpreting the geological and geomorphological evolution of the area. The results highlight the importance of dolines as markers of subsurface structures and their critical role in understanding karst landscapes. [ABSTRACT FROM AUTHOR]

Digital Elevation Models (DEMs) are a necessity for modelling many large-scale environmental processes. In this study, we investigate the potential of data from two spaceborne lidar altimetry missions, ICESat-2 and GEDI—with respect to their vertical accuracies and planimetric data collection patterns—as sources for rasterisation towards creating global DEMs. We validate the terrain measurements of both missions against airborne lidar datasets over three areas in the Netherlands, Switzerland, and New Zealand and differentiate them using land-cover classes. For our experiments, we use five years of ICESat-2 ATL03 data and four years of GEDI L2A data for a total of 252 million measurements. The datasets are filtered using parameter flags provided by the higher-level products ICESat-2 ATL08 and GEDI L3A. For all areas and land-cover classes combined, ICESat-2 achieves a bias of −0.11 m, an MAE of 0.43 m, and an RMSE of 0.93 m. From our experiments, we find that GEDI is less accurate, with a bias of 0.09 m, an MAE of 0.98 m, and an RMSE of 2.96 m. Measurements in open land-cover classes, such as "Cropland" and "Grassland", result in the best accuracy for both missions. We also find that the slope of the terrain has a major influence on vertical accuracy, more so for GEDI than ICESat-2 because of its larger horizontal geolocation error. In contrast, we find little effect of either beam power or background solar radiation, nor do we find noticeable seasonal effects on accuracy. Furthermore, we investigate the spatial coverage of ICESat-2 and GEDI by deriving a DEM at different horizontal resolutions and latitudes. GEDI has higher spatial coverage than ICESat-2 at lower latitudes due to its beam pattern and lower inclination angle, and a derived DEM can achieve a resolution of 500 m. ICESat-2 only reaches a DEM resolution of 700 m at the equator, but it increases to almost 200 m at higher latitudes. When combined, a 500 m resolution lidar-based DEM can be achieved globally. Our results indicate that both ICESat-2 and GEDI enable accurate terrain measurements anywhere in the world. Especially in data-poor areas—such as the tropics—this has potential for new applications and insights. [ABSTRACT FROM AUTHOR]

ABSTRACTFlood models rely on accurate topographic data representing the bare earth ground surface. In many parts of the world, the only topographic data available are the free, satellite-derived global Digital Elevation Models (DEMs). However, these have well-known inaccuracies due to limitations of the sensors used to generate them (such as a failure to fully penetrate vegetation canopies and buildings). We assess five contemporary, 1 arc-second (≈30 m) DEMs -- FABDEM, Copernicus DEM, NASADEM, AW3D30 and SRTM -- using a diverse reference dataset comprised of 65 airborne-LiDAR surveys, selected to represent biophysical variations in flood-prone areas globally. While vertical accuracy is nuanced, contingent on the specific metrics used and the biophysical character of the site being assessed, we found that the recently-released FABDEM consistently ranked first, improving on the second-place Copernicus DEM by reducing large positive errors associated with forests and buildings. Our results suggest that land cover is the main factor explaining vertical errors (especially forests), steep slopes are associated with wider error spreads (although DEMs resampled from higher-resolution products are less sensitive), and variable error dependency on terrain aspect is likely a function of horizontal geolocation errors (especially problematic for AW3D30 and Copernicus DEM).

Abstract. This article provides an overview of modern remote sensing techniques in archaeology and their practical applications. The widespread use of GIS technologies and remote sensing methods such as photogrammetry and laser scanning is a distinguishing characteristic of contemporary archaeology. Remote sensing data is employed not only for the analysis of 3D archaeological objects and territories but also in the digital terrain models (DTMs) analysis to search for and identify potential archaeological excavation sites. The introduction of remote sensing methods in archaeology has brought about a change in the approach to conducting archaeological studies. In the field of international research, a distinct stage known as predictive archaeology, which involves preliminary reconnaissance of an area before excavation, has emerged. The study is focused on the archaeological sites of Stantsiya Krasavka and Akhmatskoe Gorodishche, located in the Atkarsky and Krasnoarmeysky municipal districts of the Saratov region. The selected study areas applied the DTM analysis, specifically using the “Hillshade” technique (analytical shading relief), which allows for the detection of previously overlooked terrain features. Based on the results, the potential of this technology for identifying individual archaeological objects using contemporary open DTMs and field geodetic survey data was analyzed. Experimental determination of the optimal DTM resolution for the identification and analysis of objects was conducted in areas previously subject to archaeological research. The experiments and comparative analysis of various laser scanning technologies led to the identification of optimal methods and filtering parameters to “exclude” vegetation and generate DTMs.

Drone photogrammetry is a swift, inexpensive, accurate, and detailed procedure that makes it possible to obtain pictures for the creation of a high spatial resolution Digital Terrain Model (DTM) with enhanced planimetric and altimetric precision. It also provides the possibility of cartographic land use. Study site: the experiment was carried out in a mountain area using a Phantom 4 RTK drone over the road connecting Demnate to Aït Bouguemez in the province of Azilal. The results were processed with Agisoft software running a TIN (Triangulated Irregular Network) based algorithm for a geometric classification (ground vs above ground). This was followed by manual intervention to increase the accuracy of the desired output. Image processing and classification helped to build a Digital Terrain Model with an altimetric RMSE of 5 cm - just 3 cm for planimetric error. This extreme accuracy is valuable when performing tasks that demand great precision, like building a detailed road development plan.Drone photogrammetry excels in the development of roads, highway, and many other tasks mainly thanks to its speed, cost-effectiveness and detail. In this paper, the results show that this technique produces high- fidelity images and can make a DTM with high precision. This higher accuracy leads to informed decisions in the planning and implementation of road work.

The existing results indicate that in the large Lundquist number regime, plasmoids play an important role in the growth and saturation of the double tearing mode (DTM). In this paper, the effect of plasma beta on the nonlinear evolution of the m / n = 2/1 DTM in large Lundquist number regime is numerically investigated in a cylinder geometry. The results demonstrate that the impact of plasma beta on plasmoid dynamics varies significantly with the separation distance between rational surfaces. In the small separation regime ( $\Delta r = 0.1$ ), no plasmoids are observed, regardless of plasma beta and resistivity. However, when the separation is relatively large ( $\Delta r = 0.2$ or $\Delta r = 0.3$ ), plasmoids exhibit highly complex behavior under different plasma beta and resistivity conditions. For the medium separation $\Delta r = 0.2$ , the resistivity threshold for the emergence of plasmoids is approximately $2.5 \times {10^{ - 6}}$ and is not affected by plasma beta. Conversely, when the separation increases to $\Delta r = 0.3$ , the resistivity threshold is significantly influenced by plasma beta. Under certain conditions, this threshold can reach as high as $1.0 \times {10^{ - 5}}$ , which is much higher than the typical value of around ${10^{ - 7}}$ . Furthermore, a preliminary case study shows that the tokamak plasma rotation shear has a significant impact on plasmoid dynamic.

Modern technologies, such as airborne laser scanning (ALS) and advanced data analysis algorithms, allow for the efficient and safe use of resources to protect infrastructure from potential threats. This publication presents a study to identify trees that may fall on highways. The study used free measurement data from airborne laser scanning and wind speed and direction data from the Institute of Meteorology and Water Management in Poland. Two methods were used to determine the crown tops of trees: PyCrown and OPALS. The effect of wind direction on potential hazards was then analyzed. The OPALS method showed the best performance in terms of detecting trees, with an accuracy of 74%. The analysis showed that the most common winds clustered between 260° and 290°. Potential threats, i.e., trees that could fall on the road, were selected. As a result of the analysis, OPALS detected between 140 and 577 trees, depending on the chosen strategy. The presented research shows that combining ALS technology with advanced algorithms and wind data can be an effective tool for identifying potential hazards associated with falling trees on highways. [ABSTRACT FROM AUTHOR]

Mapping the terrain and the Earth's surface can be performed through non-contact methoYes, that is correct.ds such as laser scanning. This is one of the most dynamic and effective data collection methods. This case study aims to analyze the usability of spatial data from available sources and to choose the appropriate solutions and procedures for processing the point cloud of the area of interest obtained from available web applications. The processing of the point cloud obtained by airborne laser scanning results in digital terrain models created in selected software. The study also included modeling of different types of residential development, and the results were evaluated. Different data sources may have compatibility issues, which means that the position of the same object from different spatial data databases may not be identical. To address this, deviations of the corresponding points were determined from various data sources such as Real Estate Cadaster, ZBGIS Buildings, LiDAR point cloud, orthophoto mosaic, and geodetic measurements. These deviations were analyzed according to their size and orientation, with the average deviations ranging from 0.22 to 0.34 m and standard deviations from 0.11 to 0.20 m. The Real Estate Cadaster was used as the correct basis for comparison. The area of the building was also compared, with the slightest difference being present between the Real Estate Cadaster and geodetic measurement. The difference was zero after rounding the area to whole numbers. The maximum area difference was +5 m2 for ZBGIS Buildings. [ABSTRACT FROM AUTHOR]

High-resolution topographic data are crucial for delta water management, such as hydrological modeling, inland flood routing, etc. Nevertheless, the availability of high-resolution topographic data is often lacking, particularly in low-lying regions in developing countries. This data scarcity poses a significant obstacle to inland flood modeling. However, collecting detailed topographic data is demanding, time-consuming, and costly, making remote sensing techniques a promising solution for developing flood inundation analysis models worldwide. This study presents a novel understanding for utilizing topographical elevations obtained using remote sensing techniques to create a flood inundation analysis model. In a study of three watersheds, Kameda, Niitsu, and Shirone (Japan), the assessment of digital terrain models (DTMs) showed that remote sensing-based DTMs (RS-DTMs) exhibited high reliability of coefficient of determination (R2) and root-mean-square errors, compared with the airborne LiDAR-based topography from the Geospatial Information Authority of Japan. Comparing the flood modeling results from LiDAR data and RS-DTM, with Kameda and Niitsu performing favorable outcomes, Shirone exhibited less accurate results. We hypothesized that this was caused by the topographic distortions due to lack of evenly distributed reference points. Hence, we revised the topography by adjusting both the slope and intercept from the regression equation. This verification successfully showed that the flood inundation volume correlation improved, achieving R2 results for the three watersheds ranging from 0.975 to 0.997 and Nash–Sutcliffe Efficiencies ranging from 0.938 to 0.986 between the resulting flood models based on the LiDAR data and RS-DTM. Based on these findings, we recognized the significance of uniformly distributed geodetic height points. In areas lacking height references, high-precision survey instruments can be employed for achieving uniform distribution. [ABSTRACT FROM AUTHOR]

Introduction: Sports Global Navigation Satellite Systems' receivers have been providing athletes, coaches, and scientists with valuable information on movement for over two decades. As these receivers are specific measuring instruments, there is a need to determine their accuracy. This paper presents a relatively simple methodology for assessing sports receivers of this type regarding their elevation determination. Material and methods: The methodology was based on the Digital Terrain Model of Poland, a discrete representation of the topographic elevation of the land surface. Three wearable devices from different years of manufacture were selected for the preliminary study by calculating the Root Mean Square (RMS), mean elevation error, and Total Elevation Gain (TEG) measures. The testing was conducted on two sections of varying length and elevation differences. Results: During the first trial, an instrument from 2019 came closest to the actual elevation (RMS = 7.0 m; mean error = -6.5 m), while during the second trial, it was an instrument from 2014 (2.5, -1.6 m, respectively). All the receivers overestimated the TEG factor during both trials. Conclusions: The applied methodology allowed the receivers to be distinguished. Due to the preliminary, pilot nature of the study, it is subject to certain limitations and recommendations listed at the end of the article. [ABSTRACT FROM AUTHOR]

In this paper, a model has been created for the automated generation of DTM (Digital Terrain Models) using a hybrid data structure based on LiDAR (Light Detection and Ranging) data. The automated process facilitates the creation and implementation of both simplified and complex DTMs using hybrid data structure. The classification of terrain into various classes is achieved through the application of the slope parameter. This model can be applied to the entire area or a specific area of interest by loading the boundaries and offers the optional capability to implement structural terrain lines in the form of watersheds. The proposed model addresses the challenge of generating DTMs in rapidly changing terrain and areas with complex landscapes, providing solutions to enhance DTM generation performance. Alongside the hybrid DTM structure, the developed model introduces a hierarchical grid with three different spatial resolutions, allowing users to adjust them based on specific requirements. The model is designed to adapt to the terrain, creating a hybrid data structure that combines the benefits of the GRID and TIN (Triangulated Irregular Network) approaches. The development and implementation of the model were carried out in ModelBuilder, within the ArcMap software environment.

Introduction: Sports Global Navigation Satellite Systems’ receivers have been providing athletes, coaches, and scientists with valuable information on movement for over two decades. As these receivers are specific measuring instruments, there is a need to determine their accuracy. This paper presents a relatively simple methodology for assessing sports receivers of this type regarding their elevation determination. Material and methods: The methodology was based on the Digital Terrain Model of Poland, a discrete representation of the topographic elevation of the land surface. Three wearable devices from different years of manufacture were selected for the preliminary study by calculating the Root Mean Square (RMS), mean elevation error, and Total Elevation Gain (TEG) measures. The testing was conducted on two sections of varying length and elevation differences. Results: During the first trial, an instrument from 2019 came closest to the actual elevation (RMS = 7.0 m; mean error = -6.5 m), while during the second trial, it was an instrument from 2014 (2.5, -1.6 m, respectively). All the receivers overestimated the TEG factor during both trials. Conclusions: The applied methodology allowed the receivers to be distinguished. Due to the preliminary, pilot nature of the study, it is subject to certain limitations and recommendations listed at the end of the article.

Copyright of Journal of Water Resources / Recursos Hídricos is the property of Associacao Portuguesa dos Recursos Hidricos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, a semi-analytical technique based on Taylor's series method namely DTM has been used to solve the differential equation which governs the motion of three types of annular FGM plates. The differential equation has been obtained using Hamilton principle and classical plate theory. The mechanical properties of the plate (Young's modulus and density) are considered to be graded in thickness direction and vary following the power-law. The behaviour of volume fraction index and radii ratio has been investigated onto first three modes of frequency parameter for all three plates. Moreover, the novelty of this paper is the application of the versatile technique DTM to study the effect of radii ratio and volume fraction index on three different types of annular FGM plates. A comparison has been made between the obtained numerical results and the results are available in the literature. A good agreement of the results verifies the accuracy of the present technique. Three-dimensional mode shapes for all three plates are also presented. [ABSTRACT FROM AUTHOR]

In this study, GIS technology was used for modelization and quantification research on historical geographic issues to provide a new research approach and technical route for the study on various crop transmission pathways and historical geographic issues such as material and cultural diffusion. In order to explore the transmission path and diffusion process of corn after its entry into China, a digital ground model of corn transmission in China was established based on the earliest recorded literature and time in various parts of China. Quantitative and model analysis methods were used to study the starting point, direction, main line, and expansion speed of corn transmission in China, and explore the relationship between its diffusion area and population growth since the late Ming Dynasty. The results showed that during the Jiajing period of the Ming Dynasty, corn was introduced to China and formed four independent sources of transmission in western Gansu(1522), southeastern Yunnan (1563), southeastern Guangxi(1564), and eastern Fujian(1545), spreading along eight routes to the whole country. The spread of corn in China was mainly along land transportation routes, and the promotion of corn dissemination by official roads and highways in the Qing Dynasty was significant. However, in the southwestern region of China, due to complex terrain and inconvenient land transportation, the spread of corn mainly extended along river valleys. Since the Qing Dynasty, corn had been rapidly spread and cultivated in China, and the population in China had grown rapidly. The two had shown a significant positive correlation. The widespread introduction of corn was one of the reasons for the rapid population growth in China from the early Qing Dynasty to 1950. [ABSTRACT FROM AUTHOR]

Remote sensing (RS) techniques are essential for studying hazardous landslide events because they capture information and monitor sites at scale. They enable analyzing causes and impacts of ongoing events for disaster management. There has been a plethora of work in the literature mostly discussing (1) applications to detect, monitor, and predict landslides using various instruments and image analysis techniques, (2) methodological mechanics in using optical and microwave sensing, and (3) quantification of surface geological and geotechnical changes using 2D images. Recently, studies have shown that the degree of hazard is mostly influenced by speed, type, and volume of surface deformation. Despite available techniques to process lidar and image/radar-derived 3D geometry, prior works mostly focus on using 2D images, which generally lack details on the 3D aspects of assessment. Thus, assessing the 3D geometry of terrain using elevation/depth information is crucial to determine its cover, geometry, and 3D displacements. In this review, we focus on 3D landslide analysis using RS data. We include (1) a discussion on sources, types, benefits, and limitations of 3D data, (2) the recent processing methods, including conventional, fusion-based, and artificial intelligence (AI)-based methods, and (3) the latest applications. [ABSTRACT FROM AUTHOR]

Airborne Laser Scanning (ALS) point cloud classification in ground and non-ground points can be accurately performed using various algorithms, which rely on a range of information, including signal analysis, intensity, amplitude, echo width, and return number, often focusing on the last return. With its high point density and the vast majority of points (approximately 99%) measured with the first return, filtering LiDAR-UAS data proves to be a more challenging task when compared to ALS point clouds. Various algorithms have been proposed in the scientific literature to differentiate ground points from non-ground points. Each of these algorithms has advantages and disadvantages, depending on the specific terrain characteristics. The aim of this research is to obtain an enhanced Digital Terrain Model (DTM) based on LiDAR-UAS data and to qualitatively and quantitatively compare three filtering approaches, i.e., hierarchical robust, volume-based, and cloth simulation, on a complex terrain study area. For this purpose, two flights over a residential area of about 7.2 ha were taken at 60 m and 100 m, with a DJI Matrice 300 RTK UAS, equipped with a Geosun GS-130X LiDAR sensor. The vertical and horizontal accuracy of the LiDAR-UAS point cloud, obtained via PPK trajectory processing, was tested using Check Points (ChPs) and manually extracted features. A combined approach for ground point classification is proposed, using the results from a hierarchic robust filter and applying an 80% slope condition for the volume-based filtering result. The proposed method has the advantage of representing with accuracy man-made structures and sudden slope changes, improving the overall accuracy of the DTMs by 40% with respect to the hierarchical robust filtering algorithm in the case of a 60 m flight height and by 28% in the case of a 100 m flight height when validated against 985 ChPs. [ABSTRACT FROM AUTHOR]

This research was carried out to investigate the application of unmanned aerial photography in estimating the respective tonnages of extracted rocks at Beautiful Rock Quarry, Lokoja, Nigeria. To attain the aim of the research, the aerial views of the 2D images captured were used to generate aerial views in the form of 3D models, namely, Digital Terrain Models (DTMs) and Digital Surface Models (DSMs). ImageJ and Regard3D components of Image Processing Software, were used for the processing of the images. Owing to the tilted aerial photograph, correction checks were conducted for the sensor coordinates, and the ground coordinates were established. Images of the extracted pits and stockpiles were analyzed by applying image processing software, which identified elevation spots and generated Z-plots for these feature. With the results generated from the image processing software, the extracted rocks from the pit were calculated to weigh 1,027,204.512tons, while the total production of aggregates sold from the quarry between 2012 and 2020 was documented to weigh 1,715,800tons. The difference between the tonnage of extracted rocks from the pit and the total production of aggregates sold was due to the swell factor of the rock (1.70), the fly rock issuing from the blasting operations and the loss of aggregates during the loading and haulage phases of the mining operation. The stockpile calculated from the 3D images weighed 44,695.39tons. The expected tonnage of the extracted rocks from the pit after excavation and crushing into aggregates was expected to be 1,746,247.670tons, which is about two percent higher than the total aggregate weighing 30,447.67 tons produced from the quarry. Therefore, approximately two percent should be allowed for the extracted tonnage expected from the pit after excavation and crushing into aggregates, as well as for the total aggregate produced from the quarry. [ABSTRACT FROM AUTHOR]

Fo r smaller locations, the traditional aerial photogrammetry techniques utilizing helicopters or airplanes are expensive and difficult. A new competitive strategy is necessary for quick spatial data collecting at a low cost and in a short amount of time for a developing nation like Nepal where geospatial data is in great demand. Currently, the Unmanned Aerial Vehicle (UAV) has become an alternative for different engineering applications, especially in surveying, one of these applications is for making a topographical map. This study demonstrates how this can be achieved using one of the evolving remote sensing technologies, Unmanned Aerial Vehicles (UAV). Besides, this study also involves image processing and topographic map production using Pix4D and GIS environments. For this study, the DJI Mavic Air-2 Advanced quadcopter collected about 207 images at a flying height of 80 m above the Kathmandu University area. An orthophoto of 2.4 cm GSD covering 127064 sq. Meter of the area was produced. The RMSE of 5.37 cm in X 4.94 cm in Y and 6.1 cm in Z was achieved with appropriate checkpoints. The measurements in the orthophoto replicated the field measurements to an error of less than 0.5% of the actual dimensions. [ABSTRACT FROM AUTHOR]

Flood models rely on accurate topographic data representing the bare earth ground surface. In many parts of the world, the only topographic data available are the free, satellite-derived global Digital Elevation Models (DEMs). However, these have well-known inaccuracies due to limitations of the sensors used to generate them (such as a failure to fully penetrate vegetation canopies and buildings). We assess five contemporary, 1 arcsecond (≈30 m) DEMs -- FABDEM, Copernicus DEM, NASADEM, AW3D30 and SRTM -- using a diverse reference dataset comprised of 65 airborne-LiDAR surveys, selected to represent biophysical variations in flood-prone areas globally. While vertical accuracy is nuanced, contingent on the specific metrics used and the biophysical character of the site being assessed, we found that the recently-released FABDEM consistently ranked first, improving on the second-place Copernicus DEM by reducing large positive errors associated with forests and buildings. Our results suggest that land cover is the main factor explaining vertical errors (especially forests), steep slopes are associated with wider error spreads (although DEMs resampled from higher-resolution products are less sensitive), and variable error dependency on terrain aspect is likely a function of horizontal geolocation errors (especially problematic for AW3D30 and Copernicus DEM). [ABSTRACT FROM AUTHOR]

Relative forest accessibility percent of accessible forest area by forest roads in comparison with total forest area is the most important indicator of the quality of primary forest accessibility. The accessible forest area by forest roads is determined by the bounded area around forest roads. Today, in the area with steep and variable slopes of terrain, a double targeted geometrical extraction distance of timber is used for the width of the bounded area around forest roads, and the forest road spacing is used in the area with a mild and uniform slope of the terrain. Both parameters depend on the targeted density of forest roads. Modern information technologies (IT) like geographical information systems (GIS) enable the quality spatial and statistical analysis of different kinds of data whose result is not accessible forest areas by current primary forest traffic infrastructure only, but also an insight into the spatial distribution of insufficient accessible areas into the forest area. The spatial distribution of these areas is significant for spatial distribution of the new routes of forest roads. The research is done in the area of Forest Management Unit (FMU) Prosara, for which the spatial analysis of a digital terrain model (DTM) determined the mostly hilly relief area. The average relative forest accessibility, based on double targeted geometrical extraction distance of timber, is 35% for the actual network of forest roads, and targeted forest road spacing is 60% for the upgraded network of forest roads.

The popularity of sports and recreational receivers of the global navigation satellite systems is steadily increasing and provides athletes, coaches, and scientists with a wealth of information on movement occurring both horizontally and vertically. Under mountainous conditions, considering the effort put in by the athlete as well as their safety, the elevation parameter appears to be particularly relevant. The aim of the study was to propose a methodology for assessing sports receivers in terms of their determination of the elevation component based on digital elevation models while paying attention to the appropriate measures for testing these devices. The methodology was applied for wrist-worn global navigation satellite systems' receivers used by the participants of an uphill running event. In terms of elevation determination, the most accurate three receivers (same model) were those supported by the barometric altimeter, in which the Root Mean Square result obtained ranged from 3.6 to 4.1 m. The majority of receivers underestimated the total elevation gain, the mean value of which was −3.8%, which does not appear to be affected by the reception of two global navigation satellite systems or the use of a barometric altimeter. The error characteristics were common within the group of receivers of a particular manufacturer. [ABSTRACT FROM AUTHOR]

Significant increase of numerous applications in engineering, biological and industrial purpose as metallic extrusion motivated this communication. This paper proposes unique computational procedure is Method of Differential Transforms (DTM) to get an exact solution for electrified conducting fluid over a semi-porous cylinder in an impermeable cylinder with effects of Joule heating and convection term. A key finding of study reports the different dimensionless parameters influences the variations in velocity and heat transport on the fluid flow are presented graphically. The graph reveals an interesting result of Nusselt number, Skin-friction and stream lines elucidates the flow characteristics. A qualitative agreement is found in the present paper and are well matched with earlier work. [ABSTRACT FROM AUTHOR]