133 research outputs found

    LASER SCANNING AND POINT CLOUD SEGMENTATION FOR CONTACTLESS GEO-MECHANICAL SURVEYING: CONSERVATIVE RESTORATION IN HYPOGEUM ENVIRONMENT

    Get PDF
    Abstract. The work presents a survey campaign specifically designed to formulate an effective restoration project in a Cultural Heritage context, the Military Shrine in Cima Grappa (Italy). Several outputs have been generated by exploring the most advanced laser scanning survey technique and some specific point cloud analysis algorithms. A detailed geometrical 3D reconstruction of human-made and natural tunnels coating materials, a geo-mechanical survey of the rock mass, a map of rock collapses and cinematic analysis of instability processes.Integrating Laser Scanning technique with the Scan-line survey allowed to perform advanced analysis and rock-mass characterisation in a predominant subterranean developed area. Most of the tunnels and underground spaces displayed rock collapses and diffuse active instability processes that certainly could have drastically slowed down surveys and analysis. The adopted techniques allowed both to proceed in acquiring data end in delivering sound outputs rapidly

    Digital Image Correlation in Assessing Structured-Light 3d Scanner's Gantry Stability: Performing David's (michelangelo) High-Accuracy 3d Survey

    Get PDF
    Abstract. The paper presents results from applying Digital Image Correlation (DIC) technique to determine deformations and verify stability on a gantry during surveying operations on the Michelangelo's David at the Galleria dell'Accademia di Firenze museum in Florence. An advanced hi-resolution Structured-light 3D scanner has been used to create a hi-detailed digital twin of the masterpiece. Considering the high scanner sensitivity, a contactless, remote and passive monitoring system of the gantry stability has been chosen to guarantee maximum freedom of movement around the David and avoid any interference during scanning operations. Due to the remarkable elevation of the statue, which reaches almost 7 meters on his pedestal, and considering the cramped operating area around the statue, an ad-hoc gantry has been designed and deployed. The sophisticated scanner's technique and the extreme hi-resolution required for the survey needed firm gantry stability during scanning operations from one side. The complex geometries and the considerable extension of the statue surface impose extended flexibility and a nimble elevation platform from the other side. Thanks to the DIC technique the gantry stability has been constantly monitored with an accuracy of 0.03 Ă· 0,04 pixels, optimising scanning scheduling and, consequently, operations efficiency. A comparison of scans with post-processed deformation patterns allowed to optimise the scanning schedule, minimising downtime, and maintaining the needed platform stability threshold for effective scanning

    Management of displaced radial neck fractures in children: Percutaneous pinning vs. elastic stable intramedullary nailing

    Get PDF
    Background: The treatment of radial neck fractures in children varies according to the displacement, angulation, and skeletal maturity. There is a general agreement that displaced radial neck fractures with more than 30 angulations (Judet type III and IV fractures) should be surgically treated. There are several treatment possibilities for Judet type III and IV fractures including percutaneous pin reduction, elastic stable intramedullary nailing (ESIN), and open reduction with or without internal fixation. In this retrospective study we compared the clinical and radiographical outcomes, and complications following intramedullary versus percutaneous pinning in displaced radial neck fractures in children. Materials and methods: Between 2000 and 2011, 20 patients were treated using closed reduction: in 12 cases we used percutaneous pinning, and in 8 cases we used ESIN. According to Judet classification the two groups were composed as follows: 10 (77 %) type III and 3 (23 %) type IV fractures in the percutaneous pinning group; 4 (57 %) type III, and 3 (43 %) type IV fractures in the ESIN group. Results: After an average of 42 months, excellent results in Mayo elbow performance scores (MEPS) were obtained in 71 and 69 % of ESIN and percutaneous pinning groups respectively, with good results in the remaining cases apart from one fair case (8 %) in the percutaneous pinning group. After a radiological evaluation, all fractures healed in excellent or good alignment. When comparing the two groups, the subjects treated with the ESIN technique had higher range of motion (ROM) in flexion, extension and pronation. No patients developed complications, except three cases of asymptomatic enlargements of the radial head, reported only in the percutaneous pinning group. Conclusion: In this research the clinical outcome, assessed with the MEPS, and the radiological alignment, were comparable between the subjects that were treated with percutaneous pinning and those with ESIN techniques; whereas the ESIN technique demonstrated higher ROM in flexion, extension and pronation. The ESIN technique seems to be the ideal approach both for the higher ROM values and for the absence of complications. © 2012 The Author(s)

    Tsunami Decision Support Systems. TDSS-2015. Outcomes of the 6th JRC ECML Crisis Management Technology Workshop

    Get PDF
    The 6th JRC ECML Crisis Management Technology Workshop on Tsunami Decision Support Systems was held in the European Crisis Management Laboratory (ECML) of the Joint Research Centre in Ispra, Italy, from 2ndto 3rd July 2015. The workshop, co-organized with DRIVER (Driving Innovation in Crisis Management for European Resilience) Consortium Partners, brought together stakeholders in the design, development and use of ICT tools for decision support. 20 participants attended the event. A good mix of regional and national service providers was represented, along with European and non-European systems providers and users. The purpose of the workshop was to show the status of the technology in this field, the specific requirements and the benefits in the use of one or another solution. During the first day participants presented their tools, while during the second they had to carry out demonstration exercises on the basis of given scenarios. In the last part of the event, they were involved in a discussion which revolved around a set of questions focused on, inter alia, strengths, weaknesses and opportunities of each tool. The main aims of the discussion were to identify both new opportunities for collaboration and for tools integration and also to “bridge the gap” between the scientific and technical level and the operational dimension. The workshop was a very good opportunity for several research and operational teams to collaboratively discuss Decision Support Systems, lessons learned, ideas for improvements and opportunities for collaboration.JRC.G.2-Global security and crisis managemen

    Vibration Analyses of a Gantry Structure by Mobile Phone Digital Image Correlation and Interferometric Radar

    Get PDF
    The study presents results from applying the Real Aperture Radar interferometry technique and Digital Image Correlation through a mobile phone camera to identify static and dynamic deformations of a gantry during surveying operations on the Michelangelo’s David at the Galleria dell’Accademia di Firenze Museum in Florence. The statue has considerable size and reaches an elevation of more than seven meters on its pedestal. An ad-hoc gantry was designed and deployed, given the cramped operating area around the statue. The scanner had a stability control system that forbid surveying in instrument movements. However, considering the unicity of the survey and its rare occurrence, the previous survey had been carried out in the year 2000; verifying stability and recording deformations is a crucial task, and necessary for validation. As the gantry does not have an on-board stability sensor, and considering the hi-survey accuracy requested, a redundant, contactless, remote monitoring system of the gantry and the statue stability was chosen to guarantee the maximum freedom of movement around the David to avoid any interference during scanning operations. Thanks to the TInRAR technique, the gantry and the statue were monitored with an accuracy of 0.01 mm. At the same time, a Digital Image Correlation analysis was performed on the gantry, which can be considered a Multi-Degree-Of-Freedom (MDOF) system, to accurately calculate the vibration frequency and amplitude. A comparison between TInRAR and DIC results reported substantial accordance in detecting gantry’s oscillating frequencies; a predominant oscillation frequency of 1.33 Hz was identified on the gantry structure by TinSAR and DIC analysis

    Brief communication "Analysis of deformations in historic urban areas using terrestrial laser scanning"

    Get PDF
    The terrestrial laser scanning (TLS) technique has been used to accurately reconstruct the 3-D shape of the walls and bastions of the historic city of Mdina (Malta) and underlying terrain. By applying this technique it has also been possible to extract additional quantitative information regarding weathering and deformational processes affecting the structures. Thus, with the aim of identifying the main instability mechanisms, a detailed 3-D crack distribution map has been drawn and the main displacement vectors have been defined

    In vivo kinematics of medial unicompartmental osteoarthritic knees during activities of daily living

    Get PDF
    Few studies exist describing unicompartmental osteoarthritic knee kinematics. Moreover, the role of the anterior cruciate ligament (ACL) in the determination of knee kinematics has not been fully described. The objective of the current study was to analyze the in vivo kinematics of knees with medial osteoarthritis (OA) and intact ACL during closed and open chained motion. Eight patients scheduled for UKA diagnosed with primary medial OA underwent knee CT-scans and video-fluoroscopy. Fluoroscopic analysis included stair climbing, chair rising and leg extension. Three-dimensional bone positions were obtained from each image by iterative procedures using a CAD-model-based shape-matching technique. Patterns of axial rotation and anterior-posterior (AP) motion of the medial and lateral femoral condyle were obtained with specific software. The femur reported an overall external rotation relative to the tibia from extension to flexion in all tasks. Average AP translation of the medial femoral condyle were smaller in open-chained tasks than in weight-bearing conditions. Average AP motion of the lateral femoral condyle reported an overall posterior translation with knee flexion. The absent natural "screw-home" mechanism and the lack of medial condyle posterior translation was explained by bone-cartilage defects and meniscal degeneration. Relevant findings were the kinematic pattern differences between weight-bearing and open chained activities, suggesting that in biphasic muscle contraction and unloaded conditions, the function of the cruciate ligaments was not physiological. The kinematics of knees with medial OA and intact ACL differed from healthy knees.Few studies exist describing unicompartmental osteoarthritic knee kinematics. Moreover, the role of the anterior cruciate ligament (ACL) in the determination of knee kinematics has not been fully described. The objective of the current study was to analyze the in vivo kinematics of knees with medial osteoarthritis (OA) and intact ACL during closed and open chained motion. Eight patients scheduled for UKA diagnosed with primary medial OA underwent knee CT-scans and video-fluoroscopy. Fluoroscopic analysis included stair climbing, chair rising and leg extension. Three-dimensional bone positions were obtained from each image by iterative procedures using a CAD-model-based shape-matching technique. Patterns of axial rotation and anterior-posterior (AP) motion of the medial and lateral femoral condyle were obtained with specific software.The femur reported an overall external rotation relative to the tibia from extension to flexion in all tasks. Average AP translation of the medial femoral condyle were smaller in open-chained tasks than in weight-bearing conditions. Average AP motion of the lateral femoral condyle reported an overall posterior translation with knee flexion.The absent natural "screw-home" mechanism and the lack of medial condyle posterior translation was explained by bone-cartilage defects and meniscal degeneration. Relevant findings were the kinematic pattern differences between weight-bearing and open chained activities, suggesting that in biphasic muscle contraction and unloaded conditions, the function of the cruciate ligaments was not physiological. The kinematics of knees with medial OA and intact ACL differed from healthy knees

    A new volar plate made of carbon-fiber-reinforced polyetheretherketon for distal radius fracture: analysis of 40 cases

    Get PDF
    BACKGROUND: Implants based on the polyetheretherketon (PEEK) polymer have been developed in the last decade as an alternative to conventional metallic devices. PEEK devices may provide several advantages over the use of conventional orthopedic materials, including the lack of metal allergies, radiolucency, low artifacts on magnetic resonance imaging scans and the possibility of tailoring mechanical properties. The purpose of this study was to evaluate the clinical results at 12-month follow-up using a new plate made of carbon-fiber-reinforced polyetheretherketon for the treatment of distal radius fractures. MATERIALS AND METHODS: We included 40 consecutive fractures of AO types B and C that remained displaced after an initial attempt at reduction. The fractures were classified according to the AO classification: 21 fractures were type C1, 9 were type C2, 2 were type C3, 2 were type B1 and 6 were type B2. RESULTS: At a 12-month follow-up no cases of hardware breakage or loss of the surgically achieved fracture reduction were documented. All fractures healed, and radiographic union was observed at an average of 6 weeks. The final Disabilities of Arm, Shoulder and Hand score was 6.0 points. The average grip strength, expressed as a percentage of the contralateral limb, was 92 %. Hardware removal was performed only in one case, for the occurrence of extensor tenosynovitis. CONCLUSION: At early follow-up this device showed good clinical results and allowed maintenance of reduction in complex, AO fractures. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV

    Design and implementation of a landslide early warning system

    Get PDF
    Abstract In this paper all the phases for the realization of the early warning system for the rockslide of Torgiovannetto in Central Italy are described. The landslide consists in a 182,000 m3 rock wedge threatening two roads which are important for local transportation. The present work encompasses all the components of an early warning system, including the geological knowledge, the risk scenarios, the kinematic characterization of the landslide, the choice and installation of the monitoring system, the setting of appropriate alarm levels and the definition of plans of civil protection. The focus is on practical and logistical issues met in all these phases and the counter-measures adopted. At present the system consists in 13 wire extensometers, 1 thermometer, 1 rain gauge and 3 cameras. Should a velocity threshold be exceeded by two or more sensors, the attention level would be entered, causing improved monitoring and surveillance. In case the behavior of the landslide changes and, by using expert judgment and forecasting methods, an imminent failure is hinted, then an alarm is issued and the upper road is closed. This paper can provide ideas and solutions for a landslide early warning system that aims to be simple, flexible, versatile and with a low probability of giving false alarms
    • …
    corecore