Automatic Reconstruction of 3D Building Models from Terrestrial Laser Scanner Data

With modern 3D laser scanners we can acquire a large amount of 3D data in only a few minutes. This technology results in a growing number of applications ranging from the digitalization of historical artifacts to facial authentication. The modeling process demands a lot of time and work (Tim Volodine, 2007). In comparison with the other two stages, the acquisition and the registration, the degree of automation of the modeling stage is almost zero. In this paper, we propose a new surface reconstruction technique for buildings to process the data obtained by a 3D laser scanner. These data are called a point cloud which is a collection of points sampled from the surface of a 3D object. Such a point cloud can consist of millions of points. In order to work more efficiently, we worked with simplified models which contain less points and so less details than a point cloud obtained in situ. The goal of this study was to facilitate the modeling process of a building starting from 3D laser scanner data. In order to do this, we wrote two scripts for Rhinoceros 5.0 based on intelligent algorithms. The first script finds the exterior outline of a building. With a minimum of human interaction, there is a thin box drawn around the surface of a wall. This box is able to rotate 360° around an axis in a corner of the wall in search for the points of other walls. In this way we can eliminate noise points. These are unwanted or irrelevant points. If there is an angled roof, the box can also turn around the edge of the wall and the roof. With the different positions of the box we can calculate the exterior outline. The second script draws the interior outline in a surface of a building. By interior outline we mean the outline of the openings like windows or doors. This script is based on the distances between the points and vector characteristics. Two consecutive points with a relative big distance will form the outline of an opening. Once those points are found, the interior outline can be drawn. The designed scripts are able to ensure for simple point clouds: the elimination of almost all noise points and the reconstruction of a CAD model

INTEGRATING AND MANAGING BIM IN GIS, SOFTWARE REVIEW

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Importance of the surface size distribution of erodible material: an improvement on the Dust Entrainment And Deposition (DEAD) Model

International audienceThis paper is based on dust aerosol cycle modelling in the atmospheric model ALADIN (Aire Limitée Adaptation dynamique Développement InterNational) coupled with the EXternalised SURFace scheme SURFEX. Its main goal is to create an appropriate mineral dust emission parameterization compatible with the global database of land surface parameters ECOCLIMAP, and the Food and Agriculture Organization (FAO) soil type database in SURFEX. An improvement on the Dust Entrainment And Deposition scheme (DEAD) is proposed in this paper by introducing the geographical variation of surface soil size distribution, the Marticorena and Bergametti (1995) formulation of horizontal saltation flux and the Shao et al. (1996) formulation of sandblasting efficiency α. To show the importance of the modifications introduced in the DEAD, both sensitivity and comparative studies are conducted in 0 dimensions (0-D) and then in 3 dimensions (3-D) between the old DEAD and the new DEAD. The results of the 0-D simulations indicate that the revised DEAD scheme represents the dust source emission better, particularly in the Bodélé depression, and provides a reasonable friction threshold velocity. In 3-D simulations, small differences are found between the DEAD and the revised DEAD for the simulated Aerosol Optical Depth (AOD) compared with the AErosol RObotic NETwork (AERONET) photometer measurements available in the African Monsoon Multidisciplinary Analyses (AMMA) databases. For the surface concentration, a remarkable improvement is noted for the revised DEAD scheme

Fuzzy logic controller for a pneumatic artificial muscle robot based on sliding mode control

Fuzzy Logic Control (FLC) has been successfully established in control systems engineering in the recent years, in other hand, Sliding Mode Control (SMC) is an active area in control research. The combination of this tow fields called Fuzzy Sliding Mode Control (FSMC) techniques to exploit the superior sides of these two controllers have drawn the attention of the scientific community. In this work, we proposed fuzzy logic controller based on the sliding mode theory to control the robot arm actuated by the pneumatics artificial muscles. Using bang-bang motion generation law, the objective of the control is the position and the velocity tracking by the robot. Simulations results demonstrate the feasibility and the advantages of our proposed research work

Neutralisation of electrically-charged insulating granular materials

International audienceDuring certain electrostatic process, diverse insulating granular materials acquire large amounts of charge, and retain it longer than necessary. The aim of this work was to model and optimize the elimination of the residual static charge of such materials. The triboelectric charging was assured by a propeller-type device. The neutralisation was carried out using a commercial-type air-assisted ionizer, located at various distances above a conveyor belt that transported the charged particles. The charge of the particles was measured before and after neutralisation using a Faraday cage. Neutralisation rates close to 100% could be achieved under optimal conditions

UAV PHOTOGRAMMETRY IMPLEMENTATION TO ENHANCE LAND SURVEYING, COMPARISONS AND POSSIBILITIES

The use of Unmanned Aerial Vehicles (UAVs) for surveying is now widespread and operational for several applications – quarry monitoring, archeological site surveys, forest management and 3D modeling for buildings, for instance. UAV is increasingly used by land surveyors especially for those kinds of projects. It is still ambiguous whether UAV can be applicable for smaller sites and property division. Therefore, the objective of this research is to extract a vectorized plan utilizing a UAV for a small site and investigate the possibility of an official land surveyor exploiting and certificating it. To do that, two plans were created, one using a UAV and another utilizing classical land surveyor instruments (Total Station). A comparison was conducted between the two plans to evaluate the accuracy of the UAV technique compared to the classical one. Moreover, other parameters were also considered such as execution time and the surface covered. The main problems associated with using a UAV are the level of precision and the visualization of the whole area. The results indicated that the precision is quite satisfactory with a maximum error of 1.0 cm on ground control points, and 4 cm for the rest of the model. On the other hand, the results showed that it is not possible to represent the whole area of interest utilizing a UAV, due to vegetation

Optimal Modeling Study of Flooding Phenomenon in Urban Area (Dam break case)

In this paper a numerical study of urban flooding caused by dam break has been undertaken. Problem statement: This study illustrated the influence of the different versions of K-epsilon turbulence model on the water flow behavior, predicted by Computational Fluid Dynamic (CFD) and validated through experiment. Approach: The water velocity, free surface profile and also secondary circulation flow along with the pressure through the city are simulated and proved. Results: Results are obtained with numerical simulation using standard k-epsilon, are relatively good agreement with the experimental results. Conclusion/Recommendations: In the present study, the velocity and the water depth are investigated to check the real capabilities of a 3D numerical code ANSYS-CFX and especially to define the optimal parameters (Mesh, boundary conditions, turbulence model,) able to simulate the flow behavior through the complex urban area, with the best accuracy

Multiobjective optimization on urban flooding using RSM and GA

International audienceUrban flooding due to climate changes, dam breaking and drainage systems being overwhelmed by rainfall causes a huge loss to mankind civilization every year all over the world. This work aims to minimize the flooding damage by optimally design the building location and interspace. The velocity, water pressure and the height of water are considered as the main factors to reduce the flooding damage. The multi-objective optimization is implemented by combing several techniques, including Design of Experiment (DOE), Response Surface Method (RSM) and the Genetic Algorithm (GA). The proposed methodology is validated with a case study on the topography of ESTP Cachan