Generation Of An Accurate, Metric Spatial Database Of A Large Multi Storied Building

This thesis presents the development of a novel method to generate an accurate, metric spatial database of a large multi storied building during construction. The algorithm uses the 3D CAD model of the building and the video of the structure captured by an Unmanned Aircraft System (UAS). The spatial database is then used to perform several inspection procedures such as, metric data analysis, spatial query for images, visualization through 3D textured model. The video is processed using a simultaneous localization and mapping (SLAM) system. SLAM generates a sparse 3D map of the environment. Our algorithm registers the 3D map with the 3D CAD model to generate the accurate metric spatial database. The user can click on the desired part of the CAD model for inspection and the image of that part will be shown by using the spatial indexing between the CAD model and the spatially distributed images. The image returned by the spatial query can be used to extract metric information. The spatial database is also used to generate a 3D textured model which provides a visual as-built documentation. The metric data calculation and textured model reconstruction methods have been compared to the state of the art Pix4D software (Latest Release (Version 3.1)). The proposed method has a mean squared error (MSE) of 31.9 cm2 and standard deviation of 4.28 cm where Pix4D had a higher MSE of 45.6 cm2 and standard deviation of 4.91 cm. Using statistical t-test and ANOVA tests we have shown that we are statistically 99% confident that the proposed algorithm has performed better than Pix4D

Seismic vulnerability assessment of the old city centre of Seixal, Portugal

The seismic vulnerability assessment of old traditional masonry building stocks, in a seismic risk mitigation perspective, is truly essential not only for buildings with recognized historical and patrimonial value, but also, in relation to regular buildings. In this sense, this paper approaches the issue of the seismic vulnerability assessment of masonry buildings through the application of a simplified methodology to building stock of the old city centre of Seixal, Portugal. This methodology is based on a vulnerability index, suitable in the evaluation of damage and in the creation of large scale loss scenarios (economical and human). Over 500 buildings were evaluated in accordance with the referred methodology and the results obtained were then integrated into a Geographical Information System tool. The integration of this kind of vulnerability and loss results into a GIS tool allows that city councils or regional authorities make their decisions based on a global view of the site under analysis, which led to more accurate and faster decisions either in terms of risk mitigation strategies or rehabilitation plans. This tool can also assumes great importance in the construction of safety and rescue plans

Integrated process of images and acceleration measurements for damage detection

The use of mobile robots and UAV to catch unthinkable images together with on-site global automated acceleration measurements easy achievable by wireless sensors, able of remote data transfer, have strongly enhanced the capability of defect and damage evaluation in bridges. A sequential procedure is, here, proposed for damage monitoring and bridge condition assessment based on both: digital image processing for survey and defect evaluation and structural identification based on acceleration measurements. A steel bridge has been simultaneously inspected by UAV to acquire images using visible light, or infrared radiation, and monitored through a wireless sensor network (WSN) measuring structural vibrations. First, image processing has been used to construct a geometrical model and to quantify corrosion extension. Then, the consistent structural model has been updated based on the modal quantities identified using the acceleration measurements acquired by the deployed WSN. © 2017 The Authors. Published by Elsevier Ltd

Analytical modelling in Dynamo

BIM is applied as modern database for civil engineering. Its recent development allows to preserve both structure geometrical and analytical information. The analytical model described in the paper is derived directly from BIM model of a structure automatically but in most cases it requires manual improvements before being sent to FEM software. Dynamo visual programming language was used to handle the analytical data. Authors developed a program which corrects faulty analytical model obtained from BIM geometry, thus providing better automation for preparing FEM model. Program logic is explained and test cases shown

MDT data quality assessment at the Calibration Centres for the ATLAS experiment at LHC

ATLAS is a large multipurpose detector, presently in the final phase of construction at the CERN Large Hadron Collider accelerator. In ATLAS the muon detection is performed by a huge magnetic spectrometer, built with the Monitored Drift Tube technology. It consists of more than 1,000 chambers and 350,000 drift tubes, which have to be controlled to a spatial accuracy better than 10 μm and an efficiency close to 100%. Therefore, the automated monitoring of the detector is an essential aspect of the operation of the spectrometer. The quality procedure collects data from online and offline sources and from the Calibration Stream at the Calibration Centres, situated in Ann Arbor (Michigan), MPI (Munich) and INFN Rome. The assessment at the Calibration Centres is performed using the DQHistogramAnalyzer utility of the ATHENA package. This application checks the histograms in an automated way and, after a further inspection with a human interface, reports results and summaries. The analysis results are stored in an Oracle Database using the COOL LCG library, through a C++ object-oriented interface. In this study a complete description of the entire chain, from the calibration stream up to the database storage is presented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85418/1/jpconf10_219_032062.pd

T-spline based unifying registration procedure for free-form surface workpieces in intelligent CMM

With the development of the modern manufacturing industry, the free-form surface is widely used in various fields, and the automatic detection of a free-form surface is an important function of future intelligent three-coordinate measuring machines (CMMs). To improve the intelligence of CMMs, a new visual system is designed based on the characteristics of CMMs. A unified model of the free-form surface is proposed based on T-splines. A discretization method of the T-spline surface formula model is proposed. Under this discretization, the position and orientation of the workpiece would be recognized by point cloud registration. A high accuracy evaluation method is proposed between the measured point cloud and the T-spline surface formula. The experimental results demonstrate that the proposed method has the potential to realize the automatic detection of different free-form surfaces and improve the intelligence of CMMs

3D Data Processing Toward Maintenance and Conservation. The Integrated Digital Documentation of Casa de Vidro

During the last decade, 3D integrated surveys and BIM modelling procedures have greatly improved the overall knowledge on some Brazilian Modernist buildings. In this framework, the Casa de Vidro 3D survey carried out by DIAPReM centre at Ferrara University, beside the important outputs, analysis and researches achieved from the point cloud database processing, was also useful to test several awareness increasing activities in cooperation with local stakeholders. The first digital documentation test of the Casa de Vidro allowed verifying the feasibility of a full survey on the building towards the restoration and possible placement of new architectures into the garden as an archive-museum of the Lina Bo and P.M. Bardi Foundation. Later, full 3D integrated survey and diagnostic analysis were carried out to achieve the total digital documentation of the house sponsored by the Keeping it Modern initiative of Getty Foundation (Los Angeles). Following its characteristics, the survey had to take into consideration the different architectural features, up to the relationship of architecture and nature. These 3D documentation activities and the point cloud processing allowed several analysis in a multidisciplinary framework