Engineering-Oriented Geometry Methods for Modeling and Analyzing Scanned Data

2011 ◽  
Vol 11 (2) ◽  
Author(s):  
Anath Fischer
Keyword(s):  
Geometric Modeling ◽  
Multiscale Analysis ◽  
Large Scale ◽  
Mechanical Analysis ◽  
Shape Reconstruction ◽  
Engineering Problem ◽  
Design Analysis ◽  
New Paradigm ◽  
Reconstruction Methods ◽  
Geometric Reconstruction

The emerging field of Engineering Oriented Geometry (EOG) comprises new and extended geometric modeling methods that are directly related to the shared inherent engineering attributes of design, analysis, and manufacturing. This paper describes EOG methods that can be applied to scanned data, focusing on two main sub-areas: (a) shape reconstruction from scanned data; and (b) geometric modeling for analysis. The paper describes the main developments in geometric shape reconstruction methods for scanned data and in geometric modeling for analysis. In the field of geometric reconstruction efficient algorithms have been developed to cope with the open engineering problem of reconstruction from large scale, noisy, and incomplete data. Taken together, these solutions provide a comprehensive methodology that is fundamental to advancing the field of shape reconstruction. They constitute a new EOG model philosophy that can be implemented in CAD engineering for further processing, such as design, analysis, and manufacturing. Integrating CAD and multiscale analysis into one module creates a new paradigm that affects both fields and had the potential to lead to new areas of mechanical analysis.

Extraction of Surfaces Using Section Curves for Engineering Plants

2018 ◽  
Author(s):  
Yoshitaka Midorikawa ◽  
Hiroshi Masuda
Keyword(s):  
Large Scale ◽  
Laser Scanner ◽  
Point Clouds ◽  
3D Models ◽  
Shape Reconstruction ◽  
General Purpose ◽  
Industrial Facilities ◽  
3D Data ◽  
Reconstruction Methods ◽  
Generalized Cylinders

For simulating renovation of industrial facilities, 3D models are very useful. However, it is time-consuming to create 3D models. The terrestrial laser scanner is effective for easily capturing 3D data of large-scale facilities. So far, many researchers have proposed methods for reconstructing pipe structures in industrial plants using point-clouds. In those methods, planes and cylinders are extracted from point-clouds, but they are not enough for creating various types of equipment. Especially, in manufacturing plants for liquids and gases, rotating surfaces and generalized cylinders are typically used as well as planes and cylinders. In this paper, this paper proposes methods for extracting rotating surfaces and generalized cylinders from noisy and incomplete point-clouds. Since the section shapes of rotating surfaces and generalized cylinders are approximately ellipses, this method detects elliptic section shapes from point-clouds. Then rotating surfaces and generalized cylinders are reconstructed by extracting the center curves and section circles. Then the authors combine this method with general-purpose voxel-based shape reconstruction methods. Since this method is robust to missing points caused by occlusion, the quality of shape reconstruction can be improved even if points are partly missing due to occlusion.

The sugar and alcohol industry in the biofuels and cogeneration era: a paradigm change (part II)

2014 ◽  
pp. 97-104 ◽  
Author(s):  
Electo Eduardo Silv Lora ◽  
Mateus Henrique Rocha ◽  
José Carlos Escobar Palacio ◽  
Osvaldo José Venturini ◽  
Maria Luiza Grillo Renó ◽  
...  
Keyword(s):  
Large Scale ◽  
New Technologies ◽  
Process Integration ◽  
Animal Feed ◽  
Raw Materials ◽  
Biofuel Production ◽  
New Paradigm ◽  
Alcohol Industry ◽  
Feed Production ◽  
Steam Parameters

The aim of this paper is to discuss the major technological changes related to the implementation of large-scale cogeneration and biofuel production in the sugar and alcohol industry. The reduction of the process steam consumption, implementation of new alternatives in driving mills, the widespread practice of high steam parameters use in cogeneration facilities, the insertion of new technologies for biofuels production (hydrolysis and gasification), the energy conversion of sugarcane trash and vinasse, animal feed production, process integration and implementation of the biorefinery concept are considered. Another new paradigm consists in the wide spreading of sustainability studies of products and processes using the Life Cycle Assessment (LCA) and the implementation of sustainability indexes. Every approach to this issue has as an objective to increase the economic efficiency and the possibilities of the sugarcane as a main source of two basic raw materials: fibres and sugar. The paper briefly presents the concepts, indicators, state-of-the-art and perspectives of each of the referred issues.

scholarly journals Higher order Hamiltonian Monte Carlo sampling for cosmological large-scale structure analysis

2021 ◽  
Vol 502 (3) ◽  
pp. 3976-3992
Author(s):  
Mónica Hernández-Sánchez ◽  
Francisco-Shu Kitaura ◽  
Metin Ata ◽  
Claudio Dalla Vecchia
Keyword(s):  
Fourth Order ◽  
Large Scale ◽  
Equations Of Motion ◽  
Large Scale Structure ◽  
Real Space ◽  
Higher Order ◽  
Second Order ◽  
Scale Structure ◽  
Integration Schemes ◽  
Reconstruction Methods

ABSTRACT We investigate higher order symplectic integration strategies within Bayesian cosmic density field reconstruction methods. In particular, we study the fourth-order discretization of Hamiltonian equations of motion (EoM). This is achieved by recursively applying the basic second-order leap-frog scheme (considering the single evaluation of the EoM) in a combination of even numbers of forward time integration steps with a single intermediate backward step. This largely reduces the number of evaluations and random gradient computations, as required in the usual second-order case for high-dimensional cases. We restrict this study to the lognormal-Poisson model, applied to a full volume halo catalogue in real space on a cubical mesh of 1250 h−1 Mpc side and 2563 cells. Hence, we neglect selection effects, redshift space distortions, and displacements. We note that those observational and cosmic evolution effects can be accounted for in subsequent Gibbs-sampling steps within the COSMIC BIRTH algorithm. We find that going from the usual second to fourth order in the leap-frog scheme shortens the burn-in phase by a factor of at least ∼30. This implies that 75–90 independent samples are obtained while the fastest second-order method converges. After convergence, the correlation lengths indicate an improvement factor of about 3.0 fewer gradient computations for meshes of 2563 cells. In the considered cosmological scenario, the traditional leap-frog scheme turns out to outperform higher order integration schemes only when considering lower dimensional problems, e.g. meshes with 643 cells. This gain in computational efficiency can help to go towards a full Bayesian analysis of the cosmological large-scale structure for upcoming galaxy surveys.

Design of a Magnetic Wall-Climbing Car

2014 ◽  
Vol 526 ◽  
pp. 211-216
Author(s):  
Qiong Ying Lv ◽  
Yu Shi Mei ◽  
Xi Jia Tao
Keyword(s):  
Renewable Energy ◽  
Wind Energy ◽  
Wind Power ◽  
Large Scale ◽  
Magnetic Force ◽  
Mechanical Analysis ◽  
Heavy Duty ◽  
Magnetic Wall ◽  
Force Curves

As the trend of large-scale wind Power, People pay more attention to wind energy, which as a clean, renewable energy. Traditional unarmed climbing and crane lifting has been unable to meet the requirements of the equipment maintenance. Magnetic climb car can automatically crawl along the wall of the steel tower, the maintenance equipment and personnel can be sent to any height of the tower. The quality of the magnetic wall-climbing car is 550kg, which can carry 1.3 tons load. In this paper completed the magnetic wall-climbing car design and modeling, mechanical analysis in static and dynamic, obtained with the air gap and Magnetic Force curves. The application shows that the magnetic wall-climbing car meets the reliable adsorption, heavy-duty operation, simple operation etc..

Extended Geometric Filter for Reconstruction as a Basis for Computational Inspection

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Alexander Miropolsky ◽  
Anath Fischer
Keyword(s):  
Quality Control ◽  
Computer Model ◽  
Large Scale ◽  
Manufacturing Industry ◽  
Digital Design ◽  
Reconstruction Methods ◽  
Object Based ◽  
Inspection Process ◽  
Important Quality ◽  
Scan Data

The inspection of machined objects is one of the most important quality control tasks in the manufacturing industry. Contemporary scanning technologies have provided the impetus for the development of computational inspection methods, where the computer model of the manufactured object is reconstructed from the scan data, and then verified against its digital design model. Scan data, however, are typically very large scale (i.e., many points), unorganized, noisy, and incomplete. Therefore, reconstruction is problematic. To overcome the above problems the reconstruction methods may exploit diverse feature data, that is, diverse information about the properties of the scanned object. Based on this concept, the paper proposes a new method for denoising and reduction in scan data by extended geometric filter. The proposed method is applied directly on the scanned points and is automatic, fast, and straightforward to implement. The paper demonstrates the integration of the proposed method into the framework of the computational inspection process.

Preparation and characterization of acrylic polymer titania hybrid. A study of organicinorganic interactions in hybrid materials by micro-hardness Vickers

2002 ◽  
Vol 726 ◽  
Author(s):  
Van Nhan Nguyen ◽  
François Xavier Perrin ◽  
Jean-Louis Vernet
Keyword(s):  
Mechanical Properties ◽  
Large Scale ◽  
Sol Gel ◽  
Mechanical Analysis ◽  
Polymer Chains ◽  
Segmental Motion ◽  
Acrylic Polymer ◽  
Titania Content ◽  
Mineral Constituent ◽  
Free Films

AbstractMetal-oxide ceramer films have been developed using an acrylic polymer bearing a low amount of methacrylic acid units (ca. 4%mol) as the organic phase with titanium tetrabutoxide as the inorganic sol-gel precursor. The characterisation of free films was realized by various experimental methods. The formation of COOTi bonds prevents large scale phase separation between the organic component and the mineral network. Mechanical properties of the hybrid films have been investigated through dynamic mechanical analysis. The influence of the titania content on the damping peak amplitude suggests that titania is molecularly dispersed in the polymer matrix and that it significantly hinders the segmental motion of the polymer chains. However, the low content in potential carboxylic crosslinking sites explains why the glass transition temperature remains relatively unchanged when titania content increases. Vickers microhardness measurements used in this study allowed us to understand the contribution of the inorganic part (phase TiO2) to the mechanical properties of the polymer. The creep of hybrids has been studied carrying out hardness measurements under various indentation times. The mineral constituent leads to an important increase of the hardness and limits, in a significant way, the creep of polymer.

scholarly journals Order Reduction based on Coulomb’s and Franklin’s laws Algorithm

2021 ◽  
Author(s):  
Ram Kumar ◽  
Afzal Sikander
Keyword(s):  
Large Scale ◽  
Linear Time ◽  
Order Reduction ◽  
Absolute Error ◽  
Search Space ◽  
Engineering Problem ◽  
Reduced Order Model ◽  
Order Model ◽  
Reduced Order ◽  
Linear Time Invariant

Abstract The Coulomb and Franklin laws (CFL) algorithm is used to construct a lower order model of higher-order continuous time linear time-invariant (LTI) systems in this study. CFL is quite easy to implement in obtaining reduced order model of large scale system in control engineering problem as it employs the combined effect of Coulomb’s and Franklin’s laws to find the best values in search space. The unknown coefficients are obtained using the CFLA methodology, which minimises the integral square error (ISE) between the original and proposed ROMs. To achieve the reduced order model, five practical systems of different orders are considered. Finally, multiple performance indicators such as the ISE, integral of absolute error (IAE), and integral of time multiplied by absolute error were calculated to determine the efficacy of the proposed methodology. The simulation results were compared to previously published well-known research.

scholarly journals Reconstruction of three-dimensional maps based on closed-form solutions of the variational problem of multisensor data registration

2019 ◽  
Vol 484 (6) ◽  
pp. 672-677
Author(s):  
A. V. Vokhmintcev ◽  
A. V. Melnikov ◽  
K. V. Mironov ◽  
V. V. Burlutskiy
Keyword(s):  
Closed Form ◽  
Large Scale ◽  
Three Dimensional ◽  
Dynamic Environment ◽  
Closed Form Solution ◽  
Point Clouds ◽  
Accurate Method ◽  
Form Solution ◽  
Closed Form Solutions ◽  
Reconstruction Methods

A closed-form solution is proposed for the problem of minimizing a functional consisting of two terms measuring mean-square distances for visually associated characteristic points on an image and meansquare distances for point clouds in terms of a point-to-plane metric. An accurate method for reconstructing three-dimensional dynamic environment is presented, and the properties of closed-form solutions are described. The proposed approach improves the accuracy and convergence of reconstruction methods for complex and large-scale scenes.

Efficient 3D elastic full-waveform inversion using wavefield reconstruction methods

Geophysics ◽  
2016 ◽  
Vol 81 (2) ◽  
pp. R45-R55 ◽  
Author(s):  
Espen Birger Raknes ◽  
Wiktor Weibull
Keyword(s):  
Particle Velocity ◽  
Large Scale ◽  
Waveform Inversion ◽  
Transversely Isotropic ◽  
Reconstruction Method ◽  
Full Waveform Inversion ◽  
Reverse Time ◽  
Full Waveform ◽  
Time Migration ◽  
Reconstruction Methods

In reverse time migration (RTM) or full-waveform inversion (FWI), forward and reverse time propagating wavefields are crosscorrelated in time to form either the image condition in RTM or the misfit gradient in FWI. The crosscorrelation condition requires both fields to be available at the same time instants. For large-scale 3D problems, it is not possible, in practice, to store snapshots of the wavefields during forward modeling due to extreme storage requirements. We have developed an approximate wavefield reconstruction method that uses particle velocity field recordings on the boundaries to reconstruct the forward wavefields during the computation of the reverse time wavefields. The method is computationally effective and requires less storage than similar methods. We have compared the reconstruction method to a boundary reconstruction method that uses particle velocity and stress fields at the boundaries and to the optimal checkpointing method. We have tested the methods on a 2D vertical transversely isotropic model and a large-scale 3D elastic FWI problem. Our results revealed that there are small differences in the results for the three methods.

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