Cloud Creation Research Articles

Development of Learning Management Model of Collaborative Learning and Positive Coaching on Cloud Computing System

This study aims to systematically review the learning management model on cloud computing system using collaborative learning and positive coaching. The author uses the literature review to synthesize research as the main process to study related documents, books, research studies, and articles both domestically and internationally. They are selected by purposive sampling for 69 topics. The documents are analyzed by systematic review. This study is a qualitative study and uses content analysis by using keywords to discover three issues as follows: Cloud computing, Collaborative learning, and Positive coaching. From the results of this study, Cloud computing comprises six components: Cloud learning content, Cloud collaboration, Cloud communication, Cloud creation, Cloud presentation, and Cloud evaluation. The collaborative learning process has five steps as follows: Engagement phase, Exploration phase, Transformation phase, Presentation phase, and Reflection phase. Positive coaching comprises five process as follows: Construct the positive relation, Set a clear and challenging goal, Implement a challenging goal to smooth practice, Set a more challenging goal and practice smoothly, and Evaluate and expand the experience, reward the outcome and discovery.

Automatic tunnel point cloud creation using photogrammetry and deviation analysis of excavation and shotcrete surfaces

AbstractDuring new Austrian tunnelling method excavation, it is necessary to carry out an analysis of the compliance of the actual surfaces with the theoretical lines prescribed in the support types for each tunnel excavation step. With our own software solutions, we created point clouds of the excavation and shotcrete of the primary tunnel support through the automated process of photogrammetric data. Together with the tunnel axis and theoretical profiles, the georeferenced and filtered point clouds were then used in the analysis of the deviation from the theoretical lines of excavation and primary support shotcrete and shotcrete thickness. The final products of the independent analysis are deviation profiles and unwrapped extrados views with numerical results and a color legend.

BIMBot for Autonomous Laser Scanning in Built Environments

Accurate and complete 3D point clouds are essential in creating as-built building information modeling (BIM) models, although there are challenges in automating the process for 3D point cloud creation in complex environments. In this paper, an autonomous scanning system named BIMBot is introduced, which integrates advanced light detection and ranging (LiDAR) technology with robotics to create 3D point clouds. Using our specially developed algorithmic pipeline for point cloud processing, iterative registration refinement, and next best view (NBV) calculation, this system facilitates an efficient, accurate, and fully autonomous scanning process. The BIMBot’s performance was validated using a case study in a campus laboratory, featuring complex structural and mechanical, electrical, and plumbing (MEP) elements. The experimental results showed that the autonomous scanning system produced 3D point cloud mappings in fewer scans than the manual method while maintaining comparable detail and accuracy, demonstrating its potential for wider application in complex built environments.

DIGITIZATION APPROACHES FOR URBAN CULTURAL HERITAGE: LAST GENERATION MMS WITHIN VENICE OUTDOOR SCENARIOS

Abstract. This paper explores the use of Mobile Mapping Systems (MMSs) for urban Cultural Heritage (CH) documentation, which has become an increasingly important tool in surveying for rapid and accurate mapping of both internal and external environments. The study evaluates the performance of the STONEX® X120GO SLAM Laser Scanner, a recent commercial MMS, in documenting CH in various outdoor applications, including urban environments and inaccessible places. The methodology was applied to three test fields in the historic centre of Venice, which include Piazza San Marco, Santa Marta area, and the Venetian canal called Rio de le Toresele. The STONEX® X120GO SLAM Laser Scanner is composed of a 360° rotating head LiDAR scanner, three 5MP cameras, and an Inertial Measurement Unit (IMU) and Global Navigation Satellite System (GNSS) for geospatial 3D point cloud creation. The MMS was evaluated in terms of time, accuracy, and point cloud resolution against other active sensors such as Terrestrial Laser Scanners (TLSs) and spherical photogrammetry. The results suggest that the tested MMS has reached optimal levels of development, enabling high-speed data collection and providing good accuracy for significant urban CH sites. Overall, the paper highlights the importance and potential of MMSs for CH documentation and emphasizes the need for ongoing development to optimize the management process.

Can a Symbolic Mega-Unit of Radiative Forcing (RF) Improve Understanding and Assessment of Global Warming and of Mitigation Methods Using Albedo Enhancement from Algae, Cloud, and Land (AEfACL)?

By expressing radiative forcing (RF) in a symbolic mega-unit we better communicate, to governing organizations and the public, the extent of global warming (GW) and the potency of mitigation methods while also ‘translating’ different GW measures to better explain their interrelationship. An easily visualized symbol that has been suggested is the net shading, or mega-unit, of RF of a “standard 1 km2 cumulus cloud over one day of −25 W/m2” (ScCd). As defined, ScCd is equal to 600,000 kWh and equivalent to Temporary heat radiation Equivalent Carbon (ThrEC) of 18,400 tons of carbon heat effect, or 67,300 tons of CO2 and an approximately 0.136 albedo increase, over 1 km2. Shading over the whole earth caused by clouds is estimated by NASA as −13 W/m2. The excess of solar radiation or Earth Energy Imbalance (EEI) striking the earth was + 1.12 W/m2 in mid-2019 and has been continually increasing. Offsetting this requires the creation of additional reflective surfaces equivalent to 22.848 million square kilometers of ScCd. Such an increase could be provided by albedo enhancement from algae on the ocean surface, marine cloud brightening (MCB) or new marine cloud creation, or land area use that rejuvenates salt flats and similar locations (AEfACL). These are potentially politically acceptable and eventually could be achieved at large enough scale to be effective globally.

Creation of the Point Cloud and the 3D Model for the Above-Ground Infrastructure in the City of Chisinau by Modern Geodetic Methods

This study proves the effectiveness of laser scanning and the importance of its application in the point cloud creation and 3D model building, designing thus a model aiming to reorganize the above-ground infrastructure of the "Petrom" Oil Base in Chisinau. A comparative study of combined terrestrial laser scanning and aerial laser scanning methods will be presented, managing to offer a high-quality final product, ensuring a certain level of precision for the redevelopment and reconstruction of municipal networks. The terrestrial laser scan of the entire object was performed from 53 stations, and 604 photogrammetric images were taken during the airborne laser scan. Following the data processing through certain specialized software, the 3D model was created, with an accurate estimate of 0.0015 m - 0.002 m.

Thermal instability and multiphase gas in the simulated interstellar medium with conduction, viscosity, and magnetic fields

ABSTRACT Thermal instability plays a crucial role in the formation of multiphase structures and their dynamics in the interstellar medium, and is a leading theory for cold cloud creation in various astrophysical environments. In this paper, we use 2D simulations to investigate thermal instability under the influence of various initial conditions and physical processes. We experiment with Gaussian random field (GRF) density perturbations of different initial power spectra. We also enrol thermal conduction and physical viscosity in isotropic hydrodynamic and anisotropic magnetohydrodynamic (MHD) simulations. We find that the initial GRF spectral index α has a dramatic impact on the pure hydrodynamic development of thermal instability, influencing the size, number, and motions of clouds. Cloud fragmentation happens due to two mechanisms: tearing and contraction rebound. In the runs with isotropic conduction and viscosity, the structures and dynamics of the clouds are dominated by evaporation and condensation flows in the non-linear regime, and the flow speed is regulated by viscosity. Cloud disruptions happen as a result of the Darrieus–Landau instability. However, at very late times, all individual clouds merge into one cold structure in all hydrodynamic runs. In the MHD case, the cloud structure is determined by both the initial perturbations and the initial magnetic field strength. In high-β runs, anisotropic conduction causes dense filaments to align with the local magnetic fields and the field direction can become reoriented. Strong magnetic fields suppress cross-field contraction and cold filaments can form along or perpendicular to the initial fields.

Geometry accuracy analysis of the three-dimensional model using the close-range photogrammetry method for conservation object of culture (case study: Cow Statue, Faculty Of Livestock, Diponegoro University)

Conservation of cultural objects in the form of maintenance and protection to keep objects from damage and authenticity important. Documentation using a three-dimensional model (3D model) is a cheap, effective and relatively fast solution. The documentation results in the form of a three-dimensional model, which itself must have a good fit of visuals and geometry. The purpose of this study was to analyze the geometry accuracy level and the suitability of the three-dimensional model of physical objects using the close-range photogrammetric method (CRP). This study, using a non-metric camera, namely a DSLR camera to take photos of objects simultaneously and thoroughly according to the CRP concept. The results of the photos are processed based on near-range photogrammetric methods using the VisualSfM technique in point cloud creation followed by Meshlab in making three-dimensional models. The results showed that the shape and color of the model were quite good but still had some rough areas due to a lack of point cloud data. The level of color suitability of the digital model is quite good with several colors in coarse-textured areas that look less suitable for physical objects. The suitability of the geometry of the model through the difference in distance between the test points has an average of 3.524 mm and a standard deviation of 2.989 mm.

Investigating the feasibility of artificial convective cloud creation

In this paper, we study the physical justification and experimental possibility of stimulating convection in the atmosphere to create artificial convective clouds and precipitation. A prerequisite for creation of artificial convective clouds is the presence of water vapor in the atmosphere; this is an encouraging factor as water vapor is present even in regions with an arid climate. Furthermore, numerous cases of convective cloud development under the influence of powerful heat sources are known, even for days lacking conditions for natural cloud development. In this paper, we analyze the results and failure causes of worldwide experiments with meteotrons, which are stationary installations designed to initiate powerful updrafts. To enhance meteotron jet buoyancy, a combined method based on use of a turbojet engine is proposed; the jet output by the engine creates an aerosol cloud that absorbs shortwave solar radiation. An overview of mathematical models of convective jets is given and the assumptions made during mathematical formulation of the problem are analyzed. Theoretical and laboratory results are compared. A mathematical model of a convective jet is proposed and an analytical solution is obtained in cylindrical coordinates. It is shown that the upward flow velocity decreases to a minimum at an altitude where the jet and environment temperatures are aligned. In contrast, the jet radius increases and, at the temperature equalization height, the jet adopts an umbrella form. We conclude that, for an artificially created stream to contribute to development of cloud convection, the temperature equalization height should be equal to or greater than the condensation level. The results obtained in this study can be used in the trials on creation of artificial updrafts and clouds.

Nature and Origins of Rich Complexes of C iv Associated Absorption Lines

Abstract Rich complexes of associated absorption lines (AALs) in quasar spectra provide unique information about gaseous infall, outflows, and feedback processes in quasar environments. We study five quasars at redshifts z ~ 3.1–4.4 with AAL complexes containing from 7 to 18 C iv λ1548, 1551 systems in high-resolution spectra. These complexes span velocity ranges ≲3600 km s−1 within ≲8200 km s−1 of the quasar redshifts. All are highly ionized with no measurable low-ionization ions like Si ii or C ii, and all appear to form in the quasar/host galaxy environments based on evidence for line locking, partial covering of the background light source, strong N v absorption, and/or roughly solar metallicities, and on the implausibility of such complexes forming in unrelated intervening galaxies. Most of the lines in all five complexes identify high-speed quasar-driven outflows at velocity shifts v ≲ − 1000 km s−1. Four of the complexes also have lines at smaller blueshifted velocities that might form in ambient interstellar clouds, low-speed outflows, or at feedback interfaces in the host galaxies where high-speed winds impact and shred interstellar clouds. The partial covering we measure in some of the high-speed outflow lines require small absorbing clouds with characteristic sizes ≲1 pc or ≲0.01 pc. The short survival times of these clouds require locations very close to the quasars, or cloud creation in situ at larger distances perhaps via feedback/cloud-shredding processes. The AAL complex in one quasar, J1008+3623, includes unusually narrow C iv systems at redshifted velocities 350 ≲ v ≲ 640 km s−1 that are excellent candidates for gaseous infall toward the quasar, e.g., “cold-mode” accretion or a gravitationally bound galactic fountain.

Geometric Modeling and 3D Printing Using Recursively Generated Point Cloud

Previous studies have reported that a recursive process called the point cloud creation algorithm (PCA) that generates a point cloud is useful for reverse engineering a planner shape. This study elucidates the characteristics of the parameters used in the recursive process as well as its ability in geometric modeling and 3D printing of 3D shapes. In the recursive process, three constants (center point, initial distance, and initial angle) and two variables (instantaneous distance and instantaneous rotational angle) are employed. The shape-modeling characteristics of the constants and variables are elucidated using some commonly used shapes (straight-line, circle, ellipses, spiral, astroid, S-shape, and leaf-shape). In addition, the shape-modeling capability of the recursive process as a whole is quantified using two parameters called the radius of curvature and aesthetic value. Moreover, an illustrative example that shows the efficacy of the recursive process in virtual and physical prototyping of a relatively complex 3D object is presented. The results show that reverse engineering performed by the recursive-process-created point cloud is free from computational complexity compared to reverse engineering performed by the 3D-scanner-created point cloud. As such, the outcomes of this study enrich the field of reverse engineering.

Morpho–Sedimentary Monitoring in a Coastal Area, from 1D to 2.5D, Using Airborne Drone Imagery

Coastal areas are among the most endangered places in the world, due to their exposure to both marine and terrestrial hazards. Coastal areas host more than two-thirds of the world’s population, and will become increasingly affected by global changes, in particular, rising sea levels. Monitoring and protecting the coastlines have impelled scientists to develop adequate tools and methods to spatially monitor morpho-sedimentary coastal areas. This paper presents the capabilities of the aerial drone, as an “all-in-one” technology, to drive accurate morpho-sedimentary investigations in 1D, 2D and 2.5D at very high resolution. Our results show that drone-related fine-resolution, high accuracies and point density outperform the state-of-the-science manned airborne passive and active methods for shoreline position tracking, digital elevation model as well as point cloud creation. We further discuss the reduced costs per acquisition campaign, the increased spatial and temporal resolution, and demonstrate the potentialities to carry out diachronic and volumetric analyses, bringing new perspectives for coastal scientists and managers.

GEOREFERENCING AND REPROJECTION ERROR INVESTIGATION ON IMAGE BASED 3D DIGITIZATION AND MAPPING OF HISTORICAL BUILDINGS

Abstract. Image based dense point cloud creation is easy and low-cost application for three dimensional digitization of small and large scale objects and surfaces. It is especially attractive method for cultural heritage documentation. Reprojection error on conjugate keypoints indicates accuracy of the model and keypoint localisation in this method. In addition, sequential registration of the images from large scale historical buildings creates big cumulative registration error. Thus, accuracy of the model should be increased with the control points or loop close imaging. The registration of point point cloud model into the georeference system is performed using control points. In this study historical Sultan Selim Mosque that was built in sixteen century by Great Architect Sinan was modelled via photogrammetric dense point cloud. The reprojection error and number of keypoints were evaluated for different base/length ratio. In addition, georeferencing accuracy was evaluated with many configuration of control points with loop and without loop closure imaging.

ANALYZING OF THE TERRESTRIAL LASER SCANNER GEOREFERENCING USING GNSS

Recent years have witnessed emerging the cutting-edge method for point cloud creation using terrestrial laser scanner (TLS). The TLS manufacturers declare accuracies of their instruments up to the millimeter level. However, different constraints could degrade the accuracy of point cloud created by TLS. One of the obvious factors that may directly affect the accuracy of the results is a method of registration and georeferencing. In this paper, the indirect georeferencing using GNSS has been researched. The real time kinematic (RTK) technique has been suggested to measure GNSS points. The conducted test shows that average of 30 minutes data RTK-GNSS is enough to coincide with TLS data. Also, test reveals no improvements when adding more GNSS points. Nevertheless, there is an improvement in accuracy when more scans are conducted.

Reconstruction of stented coronary arteries from optical coherence tomography images: Feasibility, validation, and repeatability of a segmentation method.

Optical coherence tomography (OCT) is an established catheter-based imaging modality for the assessment of coronary artery disease and the guidance of stent placement during percutaneous coronary intervention. Manual analysis of large OCT datasets for vessel contours or stent struts detection is time-consuming and unsuitable for real-time applications. In this study, a fully automatic method was developed for detection of both vessel contours and stent struts. The method was applied to in vitro OCT scans of eight stented silicone bifurcation phantoms for validation purposes. The proposed algorithm comprised four main steps, namely pre-processing, lumen border detection, stent strut detection, and three-dimensional point cloud creation. The algorithm was validated against manual segmentation performed by two independent image readers. Linear regression showed good agreement between automatic and manual segmentations in terms of lumen area (r>0.99). No statistically significant differences in the number of detected struts were found between the segmentations. Mean values of similarity indexes were >95% and >85% for the lumen and stent detection, respectively. Stent point clouds of two selected cases, obtained after OCT image processing, were compared to the centerline points of the corresponding stent reconstructions from micro computed tomography, used as ground-truth. Quantitative comparison between the corresponding stent points resulted in median values of ~150 μm and ~40 μm for the total and radial distances of both cases, respectively. The repeatability of the detection method was investigated by calculating the lumen volume and the mean number of detected struts per frame for seven repeated OCT scans of one selected case. Results showed low deviation of values from the median for both analyzed quantities. In conclusion, this study presents a robust automatic method for detection of lumen contours and stent struts from OCT as supported by focused validation against both manual segmentation and micro computed tomography and by good repeatability.

Fast and scalable 3D cyber-physical modeling for high-precision mobile augmented reality systems

Mobile augmented reality is an emerging technique which allows users to use a mobile device's camera to capture real-world imagery and view real-world physical objects and their associated cyber-information overlaid on top of imagery of them. One key challenge for mobile augmented reality is the fast and precisely localization of a user in order to determine what is visible in their camera view. Recent advances in Structure-from-Motion (SfM) enable the creation of 3D point clouds of physical objects from an unordered set of photographs taken by commodity digital cameras. The generated 3D point cloud can be used to identify the location and orientation of the camera relative to the point cloud. While this SfM-based approach provides complete pixel-accurate camera pose estimation in 3D without relying on external GPS or geomagnetic sensors, the preparation of initial 3D point cloud typically takes from hours to a day, making it difficult to use in mobile augmented reality applications. Furthermore, creating 3D cyber-information and associating it with the 3D point cloud is also a challenge of using SfM-based approach for mobile augmented reality. To overcome these challenges in 3D point cloud creation and cyber-physical content authoring, the paper presents a new SfM framework that is optimized for mobile augmented reality and rapidly generates a complete 3D point cloud of a target scene up to 28 times faster than prior approaches. Key improvements in the proposed SfM framework stem from the use of (1) state-of-the-art binary feature descriptors, (2) new filtering approach for accurate 3D modeling, (3) optimized point cloud structure for augmented reality, and (4) hardware/software parallelism. The paper also provides a new image-based 3D content authoring method designed specifically for the limited user interfaces of mobile devices. The proposed content authoring method generates 3D cyber-information from a single 2D image and automatically associates it with the 3D point cloud.

Automatic BIM component extraction from point clouds of existing buildings for sustainability applications

Abstract Building information models (BIMs) are increasingly being applied throughout a building's lifecycle for various applications, such as progressive construction monitoring and defect detection, building renovation, energy simulation, and building system analysis in the Architectural, Engineering, Construction, and Facility Management (AEC/FM) domains. In conventional approaches, as-is BIM is primarily manually created from point clouds, which is labor-intensive, costly, and time consuming. This paper proposes a method for automatically extracting building geometries from unorganized point clouds. The collected raw data undergo data downsizing, boundary detection, and building component categorization, resulting in the building components being recognized as individual objects and their visualization as polygons. The results of tests conducted on three collected as-is building data to validate the technical feasibility and evaluate the performance of the proposed method indicate that it can simplify and accelerate the as-is building model from the point cloud creation process.

Influence of solar elevation in radiometric and geometric performance of multispectral photogrammetry

Solar elevation is an important factor in passive, airborne data collection. The minimum solar elevation allowed in missions for topographic mapping is typically 30° from the horizon. A general hypothesis is that the new, high dynamic range, digital large-format photogrammetric sensors allow for high data quality, even with lower solar elevations, which would improve the feasibility and cost-efficiency of photogrammetric technology in various applications. Objectives of this study were to investigate theoretically and empirically the impacts of solar elevation in modern photogrammetric processes. Two cutting-edge aspects of novel photogrammetric technology were considered: point cloud creation by automatic image matching and reflectance calibration of image data. For the empirical study, we used image data collected by a large-format photogrammetric camera, Intergraph DMC, with low (25–28°) and medium (44–48°) solar elevations from 2, 3 and 4 km heights. We did not detect negative influences of decreasing solar elevation during our general evaluations: an analysis of image histograms showed that the ranges of digital numbers could be tuned to similar levels with exposure settings, and evaluations of density and the accuracy of point clouds did not show any reduction of quality. We carried out detailed evaluations in forests, roads and fields. Our results did not indicate deterioration of the quality in sun-illuminated areas with decreasing solar elevation. In shadowed areas, we observed that the variation of image signal was reduced in comparison to sun-illuminated areas and emphasized the issue of complication of reflectance calibration. Artefacts appeared in automatically generated point clouds in areas shadowed by trees, which we observed in flat objects as up to 3 times increased random height variation and decreased success in measuring the terrain surface. Our results also showed that the overall performance of point cloud generation was high. Typically, point clouds could be derived even from a single stereo model with the point density corresponding to the GSD, but some expected and unexpected failures also appeared. The height accuracy was dependent on the object properties and the intersection geometry; the height accuracy was 0.5–2 times GSD at well defined objects. Our conclusions were that in the future it is of increasing importance to quantify the sensitivity of different methods on the radiometric properties of the image data. It is also important to develop interpretation methods that are not sensitive to shadows, in order to enable optimal use of photogrammetric technology in normal to rapid response applications.

Stochastic Billboard Clouds for Interactive Foliage Rendering

We render tree foliage levels of detail (LODs) using a new adaptation of billboard clouds. Our contributions are a simple and efficient billboard cloud creation algorithm designed specifically for tree foliage, and a method for smooth transitions between LODs. The cloud creation algorithm performs stochastic search to find a set of billboards that approximate the base mesh. Billboard clouds offer an alternative to traditional triangle reduction methods, which break down for foliage with its small, disconnected pieces of geometry. By projecting foliage geometry onto large precomputed textures, our method shifts the bulk of the runtime rendering to the fragment processing stage. This results in higher frame rates for most viewing distances, with adjustable visual accuracy. We give results for foliage from two fully detailed tree models and discuss implementation issues.