Recent architectonic trends in the design of truss systems with multiple structural members, as well as design and construction requirements for the evaluation of the ultimate strength of hollow section walls at the location of the joints (chord failure resistance), can sometimes lead to cases in which tubular joints cannot be managed in a systematic manner in accordance with current codes and guidelines. Often, they are not easy to compare with technical recommendations and those from the literature. As a result, this means that the designer has to use alternative criteria for evaluating the ultimate strength of the structural joints, including, as stated here, numerical analyses which are specifically intended to discover the ultimate design loads. This work refers precisely to the use of the finite element method for numerical analyses, adopted as an additional and comparative means for the European Standard EN_1993-1-8 (Design of Joints) [1] for research into chord failure resistance of multi-intersection tubular joints with non-regular geometry.

This paper describes the non-linear mechanical response of a skylight shell structure, created using a glass envelope and structural steel members, in the event of an explosion. The system, currently under construction, has a geometrical axis of 52.50m (maximum) and 40.00m (minimum), and the span ratio n = 6.75 %. Several pressure wave signals were obtained, according to the American specifications of TM5-1300 [1], and the consequent non-linear time-history response of the system were investigated.

Reverse Time Migration is a key algorithm for seismic imaging. On the other hand, RTM implies a huge consumption of computing resources (I/O, RAM, CPU) such that RTM runs have a deep impact on the overall exploitation of a production cluster. Moreover, a significant effort is required to administer thousands of single shot migrations and to collect partial results. Although the workflow is not awfully complicated, the huge amount of jobs and partial results needs particular attention, since any error resulting from hardware/software failures during one of the jobs can irreparably taint the final result. The main goal of the RiTMo framework is to simplify the execution of RTM projects, implementing the typical workflow in production environments where several other applications may be running concurrently. The RiTMo framework allows to easily configure and administer RTM projects; it is able to expose the full project as a single meta-job, hiding the underlieing complexity to the user. RiTMo is completely automatic, fault tolerant and reliable. Management of resources is flexible, as it can dynamically change the number of running jobs. Moreover, RiTMo enhances the overall throughput of the entire cluster, due to the efficient control of the resource usage.

PreviousNext No AccessSEG Technical Program Expanded Abstracts 2010Optimal implementation of Finite Difference stencils for the solution of the wave equation on multicore processorsAuthors: Nicola BienatiChristopher DankenCristiano CalonaciRoberto GoriNicola BienatiClara Andreoletti eni e&pSearch for more papers by this author, Christopher DankenIntel GmbHSearch for more papers by this author, Cristiano CalonaciCinecaSearch for more papers by this author, and Roberto GoriCinecaSearch for more papers by this authorhttps://doi.org/10.1190/1.3513529 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract Finite differences provide the most accurate solution of the wave equation but are also extremely computing intensive. The use of the most advanced hardware is therefore mandatory in order to obtain reasonable computing time. Nonetheless, this is not enough: software must guarantee the maximum efficiency in the usage of such resources. In this paper we discuss the performance improvement achieved through an efficient implementation of finite differences on a multicore CPU.Permalink: https://doi.org/10.1190/1.3513529FiguresReferencesRelatedDetailsCited ByTwo-grid genetic algorithm full-waveform inversionAlfredo Mazzotti, Nicola Bienati, Eusebio Stucchi, Andrea Tognarelli, Mattia Aleardi, and Angelo Sajeva1 December 2016 | The Leading Edge, Vol. 35, No. 12 SEG Technical Program Expanded Abstracts 2010ISSN (print):1052-3812 ISSN (online):1949-4645Copyright: 2010 Pages: 4453 publication data© 2010 Copyright © 2010 Society of Exploration GeophysicistsPublisher:Society of Exploration Geophysicists HistoryPublished: 21 Oct 2010 CITATION INFORMATION Nicola Bienati, Christopher Danken, Cristiano Calonaci, and Roberto Gori, (2010), "Optimal implementation of Finite Difference stencils for the solution of the wave equation on multicore processors," SEG Technical Program Expanded Abstracts : 3283-3287. https://doi.org/10.1190/1.3513529 Plain-Language Summary PDF DownloadLoading ...

In this paper the Italian CNR-GNDT vulnerability index for masonry buildings was modified to apply in confined masonry buildings and to obtain a reasonable relationship with the wall density per unit floor index. With this purpose, a sample of twenty-four confined masonry buildings with three and four storeys built during the last twenty-five years for social housing programs was used. A relationship has also been obtained between the value of the proposal index and the damage observed in the March 1985 Central Chile subduction earthquake (Ms=7.8).

SummaryIn craniofacial surgery it is not easy to predict the shape of the postoperative face, as muscular changes resulting from the surgery cannot be found by a simple way. Three‐dimensional (3D) computer simulation of craniofacial surgery can be extremely useful to foresee the surgical outcome. Many authors proposed computer systems for craniofacial surgical planning based on computed tomographic (CT) images. A number of methods to achieve the prediction of soft tissue behaviour have been proposed from computer‐aided surgical planning system integrating anatomy‐based 3D finite element tissue model to methods for computation of soft‐tissue deformation in craniofacial surgery directly from CT images without any intermediate geometric model. We present a review of present techniques on the use of imaging in the presurgical planning of facial surgery and reconstruction. The entire workflow of image acquisition, tissue segmentation, tissue classification, surgical planning, soft tissue displacement computer simulation and visualization is outlined and different cases of real maxillofacial surgery are illustrated.

Computer-based surgery simulation is a rapidly emerging and increasingly important area of research that combines a number of disciplines for the common purpose of improving healthcare. The objective of this paper is to provide a virtual surgery (VISU) tool for accurately planning the aesthetic impact of hard and soft tissue movements in dentoskeletal malocclusions. The approach proposed here allows direct interaction with a completely three-dimensional (3-D) computed tomography (CT) model of a solid, highly detailed structure of the head to obtain a realistic prediction of soft tissue behavior.We studied 25 patients who had facial malformations pre- and postoperatively with 3-D hard and soft tissue CT studies, and maxillary or mandibular osteotomies were simulated. The postoperative 3-D CT and facial outcomes were compared with the simulations. In 80% of the cases studied, the simulation-predicted changes, when compared with the clinical outcomes, were within the tolerance level (2 mm) established by maxillo-facial surgeons.

This paper describes a visual analysis and communication system that allows to interact with numerical simulations modeling complex natural phenomena, as volcanic eruptions, within their landscape environment. Moreover it describes how to effectively valorize the cultural context related to the territory using virtual archaeological reconstructions or historical sources whenever available having in mind educational and communication purposes.The case study presented is related to the area of the volcano Vesuvius, close to Naples Italy, very well known for the eruption occurred in 79 a.D. The volcano is currently being monitored to face future eruption risks.The framework presented not only allows to integrate the results of computing intensive simulations with geographic datasets for a fully interactive 3D high-resolution navigation around the volcano but also to performs an interactive virtual environment to access cultural heritage data.The goal is to perform new kinds of interaction and create user-friendly interfaces to communicate and explain scientific phenomena as the impact of the eruption together with cultural data providing access to databases and meta-information that exist beyond the landscape itself as GIS data, historical sources and virtual archaeology reconstructions.Moreover the framework that performs the interactive virtual environment is designed paying attention to multiplatform and multi channel portability. The interaction within the Vesuvius' landscape can be conceived not only for immersive graphics devices as Virtual Theaters but also for Virtual Sets for TV programs making contents fully available for educational purposes.

BACKGROUND:The clinical diagnosis of melanoma could be difficult for a general practitioner and, in some cases, for dermatologists. To enhance and support the clinical evaluation of pigmented skin lesions a computer-aided diagnosis has been introduced.MATERIALS AND METHODS:Images of melanocytic lesions (477 total, 42 melanomas and 435 melanocytic nevi) evaluated in epiluminescence microscopy and recorded with x16 magnification were selected. A training set of 22 melanomas and 218 nevi was randomized from the dataset. The test set was formed by the complement (the remaining 20 melanomas and 217 nevi). Furthermore, a set of images consisting of 31 melanomas and 103 nevi was selected to compare the discrimination capacity of three general practitioners and three dermatologists with experience in dermoscopy (2 years), and with the automatic data analysis for the melanoma early detection system (ADAM). Sensitivity and specificity were estimated for observer assessments and computer diagnosis.RESULTS:The entire dataset used to test the implementation of the diagnostic algorithms ADAM showed a good sensitivity and specificity performance. Compared with the physicians, the ADAM system showed a slightly higher diagnostic performance in terms of sensitivity and a lower one in terms of specificity. Dermatologists showed higher levels of specificity, but lower levels in terms of sensitivity, when compared with the general practitioners.CONCLUSION:Image analysis has the potential to distinguish nevi and melanomas and to support the clinical diagnosis of melanocytic lesions by the general practitioner.

Objective The purposes of this study were 1) to provide dermatologists as well as general practitioners with a computer aided device in order to produce an objective risk level of the melanocytic lesions helping the clinician during the diagnostic pathway 2) to compare the discrimination capacity of dermatologists and general practitioners, with the system of automated analysis ADAM (Automatic Data Analysis for Melanoma early detection). Methods The database contained 1212 melanocytic lesions: 54 melanomas (52 melanomas with breslow thickness <1 mm) and 1157 melanocytic nevi. The images have been captured with a videodermoscope using polarized light videocap, dotated with a videocamera scalar at a 20fold magnification (ds medica, milano). The images have been elaborated using the processing score of adam A training set of 27 melanomas and 279 nevi has been randomized from the dataset. The test set has been formed by the complement (the remaining 27 melanomas and 878 nevi), resulting in this way completely independent. In this situation (test vs training set) the best results obtained were: sensitivity 74%, specificity 72%, diagnostic accuracy 72%. Furthermore a set of images consisting in 31 melanomas (25 thin melanomas) and 103 nevi has been selected to compare the discrimination capacity of three dermatologists with the system of automated analysis ADAM. Results The entire dataset used to test the implementation of the diagnostic algorithms ADAM showed a good sensitivity and specificity performance. Compared with the physicians, the ADAM system has shown a slightly higher diagnostic performance in terms of sensitivity and a lower one in terms of specificity. Conclusion ADAM could give further support to the dermatologist to be integrated in the specific diagnostic pathway of global anamnestic and clinical-dermatoscopic evaluation by the specialist.

Computer-aided surgery simulation represents a rapidly emerging and increasingly important area of research that combines a number of disciplines for the common purpose of improving health care. Generally, the goal of computer-based surgery simulation is to enable a surgeon to experiment with different surgical procedures in an artificial environment. This study introduces a mathematical modelling and a numerical simulation of maxillo-facial surgery taking into account biomechanical properties of soft tissues. The approach for elastic modeling of human tissue is based on the use of embedded boundary condition techniques. Models obtained with this method allow to simulate the cranio-facial surgery directly on the natural grid of the 3D CT image of the patient avoiding any need of regridding and mesh tuning [1]. The associated matrix is solved using iterative and multi-scale methods. The integration of a distributed data management component has been developed into virtual surgery environment, to make the system distributed and suitable for clinicians involved in. The application of this approach for modeling the elastic deformation of human tissue in response to movement of bones is demonstrated both on the Visible Human Data Set of the National Library of Medicine and on the CT dataset of real patients.

This technical note describes a new software environment (HIPCOM design environment, HIDE) for the design of custom-made total hip replacements. These devices are frequently designed using general-purpose mechanical computer-aided design (CAD) programs using a set of bone contours extracted from the computer tomography (CT) images as anatomical reference. On the contrary, the HIDE system was developed to let the operator directly design the stem shape onto the CT images in a single-step operation. The operator can directly import CT data in DICOM format or use special functions to reconvert to a digital stack, the CT images printed on a radiological film. Once the stack of CT images is loaded, the operator can design the implant shape by imposing control sections directly on the CT images. The interpolation of these control sections produces the basic 3D shape of the custom-made stem. The shape is then exported to the CAD-computer-aided manufacturing (CAM) program to refine the design and to generate the part program to manufacture the implant with a CNC tooling machine. Using HIDE, the duration of design steps it affected was reduced by more than 50% with respect to the standard method in use at the manufacturer site. HIDE also improved the accuracy and the repeatability of the whole procedure. The learning curve became flat after only ten cases. These good results were achieved because of the integration of the vectorial description of the prosthetic component with the raster description of the CT data that allowed the designer to use all details available in the CT images.

Preoperative planning of total hip replacement is currently performed by the surgeons superimposing the implant templates printed on a translucent sheet on the anterior-posterior and medial-lateral X-ray projections of the patient femur. Due to the sources of error affecting this method, when the combined femoral neck anteversion and external rotation is greater then 15 degrees, a CT-based method of preoperative planning is recommended. This paper describes a CT-based preoperative planning system for total hip replacement: HIPOP. The system presents some innovative aspects on the user interface combining 2D and 3D representations of the patient anatomy and the prosthesis enhancing usability and friendliness. Moreover a set of quantitative fit and fill indicators has been develop to support the surgeon in his planning activity. Preliminary results on the surgeon learning time and repeatibility of the planning activity show that a surgeon with a basic computer knowledge can conclude his first planning session in 10 to 15 minutes. The surgeon planning repeatibility has shown to be rather high: about 1mm of variability in the position of the stem in the transaxial plane, and about 1 degrees variability on the stem orientation. Lower repeatibility has been found in the position of the prosthetic stem along the z direction. Further investigations need to be carried out to clarify this aspect.

Although pre-clinical validation procedures significantly improved in the last few years, some important factors, affecting the biomechanical performance of hip implants, are still very difficult to account for. Among the others those related to the patient (skeletal anatomy, bone quality, muscles, level of activity or osteo-integration) or to the surgeon (bone surgery, implant position and fit, joint center relocation or muscle surgery) are the most difficult to replicate in vitro or with computer models. In the present study a set of new computer methods are described, allowing when properly combined to generate with an high level of automation, finite element models of implanted femur accounting for many patient-specific and surgery-specific factors. This way a complete computational procedure can be established to support the implant designer in the early stages of the design process. Additionally, the proposed procedure can be used during clinical trials to generate patient-specific and surgeon-specific finite element models of the operated femur.

Computer-based surgery simulation represents a rapidly emerging and increasingly important area of research that combines a number of disciplines for the common purpose of improving health care. Generally, the goal of computer-based surgery simulation is to enable a surgeon to experiment with different surgical procedures in an artificial environment. This paper describes an approach for elastic modeling of human tissue based on the use of embedded boundary condition techniques. Embedded boundary condition models allow to simulate the cranio-facial surgery directly on the grid of the 3D CT image of the patient. Previously simulated operations have been performed using surface models or by using a low detailed model of the tissue volume. The approach proposed here involves complete 3D modeling of the solid high-detailed structure of the object, starting from the information present in the 3D diagnostic images. Due to the huge amount of data and to the computational complexity of the problem, a parallel version of the software has been implemented on the supercomputer Cray T3E. The application of this approach for modeling the elastic deformation of human tissue in response to movement of bones is demonstrated both on the Visible Human Data Set of the National Library of Medicine and on the CT dataset of real patients.

The problem of rebuilding a face from human remains has been, until now, especially relevant in the ambit of forensic sciences, where it is obviously oriented toward the identification of otherwise unrecognizable corpses; but its potential interest to archaeologists and anthropologists is not negligible. We present here the preliminary results of a joint research among the University of Pisa, the Visualisation Laboratory of CINECA and the CNR-ITABC (Institute of Technologies Applied to Cultural Heritage, National Research Council, Rome) whose aim is reconstructing, through Spiral Computed Tomography data and virtual modelling techniques (in our case with VTK software), 3-D models of the possible physiognomy of ancient egyptian mummies. This work is carried out through a multidisciplinary approach, involving different competences: image processing, anthropology, egyptology, computing archaeology. Main project tasks are: 1. anthropological and egyptological analysis of the head; 2. spiral CT of the head; 3. reconstruction of a 3-D model of the skull generated from CT data processing; 4. reconstruction of soft tissues; 5. application of textures fitting the somatic features. __________________________________________________________________________________________

In the 19th century, the invention of reinforced concrete (RC) technology paved the way for innovation in building methods, though its actual mechanical behavior was not fully understood for some time afterwards. The early period of the inventors and builders, such as Jean Bordenave, Paul Cottancin, A. Bonna, François Hennebique, Edmond Coignet, and N. de Tedesco, was followed by a time of intensive activity for the theorists, who developed several accurate analysis methods. A considerable contribution to this success came from the builders themselves, who adopted methods capable of achieving an effective distribution of the reinforcement, and from the technical literature, which facilitated the growth of this new technique. Initially, the theories were somewhat confused because different, sometimes contrasting approaches were used by different authors. By way of example, suffice it to mention the hypotheses developed by Mattias Koenen, P. Neumann, Edmond Coignet, N. de Tedesco, Max Ritter von Thullie, Josef Melan, J. B. Johnson, Léon Stellet, L. Lefort, F. Chaudy, Josef Anton Spitzer, Wilhelm Ritter, and Armand Considère. However, RC became a highly successful material for the 20th century, capable of satisfying the most challenging demands of designers and customers. In this paper special attention is paid to the contribution of the theories suggested at the time, in order to verify their validity in relation to our present understanding.