CRS4

URI permanente di questa Community

https://hdl.handle.net/11050/2

Fondato negli anni '90, il CRS4 è un centro di ricerca interdisciplinare che promuove lo studio, lo sviluppo e l'applicazione di soluzioni innovative a problemi provenienti da ambienti naturali, sociali e industriali. Tali sviluppi e soluzioni si basano sulla Scienza e Tecnologia dell'Informazione e sul Calcolo Digitale ad alte prestazioni. L'obiettivo principale è l'Innovazione.

La missione del Centro è quella di aiutare la Sardegna a dar vita e far crescere un tessuto di imprese hi-tech essenziali per il suo sviluppo economico e culturale.

Dal 2010 il Centro occupa circa 200 persone, tra ricercatori, tecnologi e staff di supporto, che operano in 4 settori strategici della ricerca scientifica: Biomedicina, Data Fusion, Energia e Ambiente e Società dell'Informazione. Il CRS4, inoltre, gestisce uno dei principali centri di calcolo italiani, la prima piattaforma in Italia dedicata alla genotipizzazione e al sequenziamento massivo del DNA e un laboratorio di Visual Computing allo stato dell'arte.

Sito istituzionale del CRS4

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Ora in mostra 1 - 20 di 549

3D Anatomical Functional Models for the Human Musculoskeletal System
(2006-10) Gobbetti, Enrico; MIRALab, University of Geneva-Switzerland-coordinator; Istituti Ortopedici Rizzoli-Italy-contractor; University College London-United Kingdom-contractor; INRIA-France-contractor; STAR Lab, Vrije Universiteit Brussel-Belgium-contractor; Center for Sensory-Motor Interaction, Aalborg University-Denmark-contractor; VRLab, EPFL-Switzerland-contractor; CRS4-Italy-contractor
The objective of this research and training network is to increase the development of technologies and knowledge around virtual representations of human body for interactive medical applications. The network has a specific goal: developing realistic functional 3D models for the human musculoskeletal system, the methodology being demonstrated on the lower limb. CRS4 contributes to the network in the areas of biological soft tissue modeling, visualization, and user interaction.
3d crs analysis: a new data-driven optimization strategy for the simultaneous estimate of the eight stacking parameters
(Curran Associates, 2009) Bonomi, Ernesto; Cristini, Antonio Maria; Theis, Daniela; Marchetti, Paolo
We devised a data-driven strategy for the simultaneous estimate of the eight CRS traveltime attributes, solving a global non-linear minimization problem without the need of computing gradients. The essential elements in this Eni research and development activity are the following: a conjugate-direction method supported by well known convergence properties and an iterative line-search implementing the strong Wolfe-Powell rule for the control of the steplength. The resulting algorithm can reach very good solutions in presence of many local minima.
3D functional models of monkey brain through elastic registration of histological sections
(Springer, 2005-09) Bettio, Fabio; Frexia, Francesca; Giachetti, Andrea; Gobbetti, Enrico; Pintore, Giovanni; Zanetti, Gianluigi
In this paper we describe a method for the reconstruction and visualization of functional models of monkey brains. Models are built through the registration of high resolution images obtained from the scanning of histological sections with reference photos taken during the brain slicing. From the histological sections it is also possible to acquire specifically activated neuron coordinates introducing functional information in the model. Due to the specific nature of the images (texture information is useless and the sections could be deformed when they were cut and placed on glass) we solved the registration problem by extracting corresponding cerebral cortex borders (extracted with a snake algorithm), and computing from their deformation an image transform modeled as an affine deformation plus a non-linear field evaluated as an elastically constrained deformation minimizing contour distances. Registered images and contours are used then to build 3D models of specific brains by a software tool allowing the interactive visualization of cortical volumes together with the spatially referenced neurons classified and differently colored according to their functionalities.
3D spectral reverse time migration with no-wraparound absorbing conditions
(SEG, 1998) Bonomi, Ernesto; Brieger, Leesa; Nardone, Carlo; Pieroni, Enrico
Comparative studies of methods of reverse time migration (RTM) show that spectral methods for calculating the Laplacian impose the least stringent demands on discretization stepsize; thus with spectral methods, the grid refinements often required by other methods can be avoided. Implemented with absorbing boundary conditions, which are energy-tuned to give good absorption at the boundaries, these spectral methods can be used effectively for migration, without suffering the problems of wraparound which have traditionally plagued them (Furumyra and Takenaka, 1995).
A 1D numerical study of the salt diffusion in a solar pond using finite difference tecniques
(2002-09-06) Leonardi, Erminia; Angeli, Celestino
A simple one dimensional (1D) model for the study of the salt diffusion processes in a solar pond is presented together with the implementation in a computer program using standard finite differences technique. The convective motions are not explicitly taken into account in this model and comments on their importance are presented. Albeit its simplicity the approach here reported can shed light on the basic effects taking place in the dynamics of a solar pond. The importance of the temperature profile and of the Soret effect is discussed.
A beam window target design with independent cooling for the EADF
(2000-11-30) Aragonese, Cosimo; Buono, Stefano; Fotia, Giorgio; Maciocco, Luca; Moreau, Vincent; Sorrentino, Luca
This report summarizes the study and the design of the window type target for the Energy Amplifier Demonstration Facility (EADF) [1]. The behaviour of the system in different condition has been analysed though extensive CFD simulations performed with the Star-CD commercial code [2]. The target represents one of the main technological problems related not only to the design of the EADF, but to all High Power Spallation Sources (HPSS) currently under study or in construction world-wide [4],[5]. Different configurations of the spallation EADF target are possible. Advantages and disadvantages of the different options are discussed elsewhere [6] and they are studied and analysed separately. The target device studied in this report is a window type target, cooled by diathermic oil in an independent loop. This target configuration is completely independent from the core operating conditions and gives advantages in terms of flexibility in the operation. The result of this report is a set of design data and constraints to take into account while engineering the spallation target.
A collaborative, semantic and context-aware search engine
(2007-06) Angioni, Manuela; Demontis, Roberto; Deriu, Massimo; De Vita, Emanuela; Lai, Cristian; Marcialis, Ivan; Paddeu, Gavino; Pintus, Antonio; Piras, Andrea; Sanna, Raffaella; Soro, Alessandro; Tuveri, Franco
Search engines help people to find information in the largest public knowledge system of the world: the Web. Unfortunately its size makes very complex to discover the right information. The users are faced lots of useless results forcing them to select one by one the most suitable. The new generation of search engines evolve from keyword-based indexing and classification to more sophisticated techniques considering the meaning, the context and the usage of information. We argue about the three key aspects: collaboration, geo-referencing and semantics. Collaboration distributes storage, processing and trust on a world-wide network of nodes running on users’ computers, getting rid of bottlenecks and central points of failures. The geo-referencing of catalogued resources allows contextualisation based on user position. Semantic analysis lets to increase the results relevance. In this paper, we expose the studies, the concepts and the solutions of a research project to introduce these three key features in a novel search engine architecture.
A common description for surface-tension and diﬀusion in two-component ﬂows
(2010-08) Moreau, Vincent
This report tries to develop a common representation for diffusion and surface tension in two components newtonian flows. First, we make some preliminary considerations: (1) the Navier-Stokes equations of a fluid with two immiscible components is derived from the single components equations.In this case, the surface tension arrives from external consideration; (2) we shortly review the Cahn-Hilliard and Allen-Cahn equations describing a phase separation process, the surface-tension being considered as the terminal part of this process; and (3) we report a conservative representation of the surface tension and some of its variants. Second, we reinterprete the conservative form of the single components as also valid for miscible fluids. Making an hypothesis common in diffusion phenomena, we make the surface tension naturally appear from the single phase equations. An anti-diffusive term connected with the surface tension is put in evidence. Compatibility with diffusion is discussed.
A comparative study on binary scientific data formats
(1997-10) Leone, Andrea O.; Gobbetti, Enrico
In this technical report a set of binary scientific data formats are examined. They will be presented by examining their main functionally and features.
A comparative study on modular visualization environments
(1997-10) Gobbetti, Enrico; Leone, Andrea O.
Modular Visualization Environment (MVE) systems constitute a particular class of Visualization Packages. They are not visualization programs, but rather environments to build visualization applications, accordingly to specific needs of data representation. It is now clear that MVE belong to the class of general purpose Visualization Packages, because this is the main property that characterize them. From the end-user point of view, MVE are extemely versatile and flexible. In many cases, setting up a personalized representation of data simply consists in interconnecting in a network a number of pre-existing modules with atomic functionality, creating the specific visualization pipeline that ends with the rendering of the data. The longer is the list of available modules, the bigger is the number of different visualization applications the user can build in the MVE. The following MVEs are reviewed in this document: Application Visualization System (AVS), by Advanced Visual Systems Inc., Data Explorer, by IBM Inc., and IRIS Explorer, by NAG Ltd.
A conceptual framework for multi-modal interactive virtual workspaces
(2001-11) Aspin, Rob; Da Dalto, Laurent; Fernando, Terrence; Gobbetti, Enrico; Marache, Mathieu; Shelbourn, Mark; Soubra, Souheil
Construction projects involve a large number of both direct stakeholders (clients, professional teams, contractors, etc.) and indirect stakeholders (local authorities, residents, workers, etc.). Current methods of communicating building design information can lead to several types of difficulties (e.g. incomplete understanding of the planned construction, functional inefficiencies, inaccurate initial work or clashes between components, etc.). Integrated software solutions based on VR technologies can bring significant value improvement and cost reduction to the Construction Industry. The aim of this paper is to present research being carried out in the frame of the DIVERCITY project (Distributed Virtual Workspace for Enhancing Communication within the Construction Industry - IST project n°13365), funded under the European IST programme (Information Society Technologies). DIVERCITY's goal is to develop a Virtual Workspace that addresses three key building construction phases: (1) Client briefing (with detailed interaction between clients and architects); (2) Design Review (which requires detailed input from multidisciplinary teams - architects, engineers, facility managers, etc.); (3) Construction (aiming to fabricate or refurbish the building).Using a distributed architecture, the DIVERCITY system aims to support and enhance concurrent engineering practices for these three phases allowing teams based in different geographic locations to collaboratively design, test and validate shared virtual projects. The global DIVERCITY project will be presented in terms of objectives and the software architecture will be detailed.
A CRS4 spallation Target for ESS Simulations with starccm+V5.0
(2010-07-16) Moreau, Vincent
In this document, we present a series of CFD simulations performed with starccm+V5 to build a sound proposal of windowless channel spallation target for ESS. The simulations increase progressively in complexity. The first simulation is a simple Mercury loop under the effect of a pulsed proton beam. The second one also includes a Hg/vacuum dynamic interface, using the VOF algorithm. The last simulations consider a LBE loop under vacuum subject to the thermal interaction with a proton beam, and is the basis for the proposal to ESS, still using the VOF algorithm. The simulation could be completed in a satisfactory way thanks to the use of a specific sharpening algorithm. This algorithm is explained and commented. The last simulations implementation is also described in details. The final results are shown. They appear very satisfying because the sharpening algorithm performs very well without giving rigidity to the free-surface and because the design elaborated seems a very promising basis for an ESS spallation target.
A Decision Support System based on the SWAT model for the Sardinian Water Authorities
(2005) Lorrai, Eva Barbara; Cau, Pierluigi
Sardinian Regional Authorities, such as Assessorato della Difesa dell’Ambiente, have the demanding problem of water management and protection. Targeted to their specific needs they use alternative applications and models for their specific tasks. Black box models, in the past, have been the most commonly used approach to describe the hydrological cycle. Despite their wide use, these models have shown severe limitations to take into account land use and climate changes. Physically based models can make better prediction when different combination of soil and land use, within the basin, have a significant effect on the hydrological cycle. The variety and complexity of alternative environmental problems found in the island, which vary from the impact of the agro-zootechnical to the industrial compartment, have suggested that empirical models are less suitable to predict the environmental dynamics at the catchment’s scale. Regional Authorities enact Regional Directives to enforce different European Directives, and no absolute limits can be drawn to separate their alternative field of application. The Piano di Tutela delle Acque Regional Directives aim to enforce water policy in terms of definition on where and how water resources must be used and what water protection actions need to be taken to improve water quality of rivers, lagoons, groundwater, lakes etc.. In this context, the hydrological physically based SWAT model has been chosen and applied to estimate both the water balance of the main catchments of the island and the impact of land management practices on downstream water bodies. The performance of the model has been evaluated on several stream flow monitoring gages against registered data.
A distance learning environment architecture
(2000) Sommaruga, Lorenzo; Catenazzi, Nadia; Giroux, Sylvain; Moulin, Claude
This paper presents the core architecture of NURAXI, a multimedia research platform aimed at the design, generation, deployment, management and use of intelligent distance learning environments. It describes the actors and services that are involved in the production and use of intelligent distance learning environments, the structures that are at the heart of the environment, and the processes that use these structures. The competence notion is the central component around which both author's and student's interactions gravitate. An author generates the training material on the basis of competencies to be acquired by a student, and the means to get them, i.e. the related activities and contents. A student accesses the pedagogical material by first selecting his/her learning objectives. The training path is made of dynamically created pedagogical activities. Examples of implemented activities are also shown in the paper. The platform presents a number of interesting features including re-usability of didactic components; adaptability of the training material to the student model; dynamic definition of the training path; modularity, and interoperability thanks to the adoption of standard and open solutions in terms of document structures, ontologies, design and implementation techniques. All these advantages derive from the integration of technologies such as the XML paradigm, Servlets, Software Agents, and Distributed Databases.
A distributed heterogeneous image server
(1998) Loddo, Sergio; Brelstaff, Gavin; Zanetti, Gianluigi
Digital image transmission is now ubiquitous across computer networks and thus there is increasing pressure to allow access to medical image data at sites remote from PACS locations. In fact, it may soon make economic sense to outsource medical image services - to dedicated service providers at geographical locations outside of the traditional radiology department or HIS’s. The technical challenge faced by system developers is to produce client-Viewer/server-PACS configurations that can realistically span the network. In particular, the systems must provide the performance usually expected by client medics and it must be flexible to the needs of the service providers. At CRS4 - BioMedical Applications - we are integrating various technologies derived from the www-intranet field, and object-oriented middleware to prototype technological solutions that address both the issues of performance and flexibility. These are discussed in turn below; then we provide an overview of our system.
A distributed software environment for collaborative web computing
(INSTICC, 2008-06) Pintus, Antonio; Sanna, Raffaella; Sanna, Stefano
This paper describes an extensible core software element of a distributed, peer-to-peer system, which provides several facilities in order to help the implementation of collaborative, Web-based, distributed information storing and retrieval applications based on a decentralized P2P model. Moreover, after an architectural introduction of the core distributed software module, the Core Node, this paper describes a real application, named DART Node, based on it and designed and implemented within the DART (Distributed Agent-based Retrieval Tools) project, which carries out the idea of the design and implementation of a distributed, semantic and collaborative Web search engine, including mobile devices integration use cases.
A first analysis of the solar trough transient
(2007-04) Massidda, Luca
A simplified analysis of the transient in a CSP plant that using a gas as a Heat Transfer Fluid is discussed.
A generalizable definition of chemical similarity for read-across
(BioMed Central, 2014-10-18) Floris, Matteo; Manganaro, Alberto; Nicolotti, Orazio; Medda, Ricardo; Mangiatordi, Giuseppe Felice; Benfenati, Emilio
Background: Methods that provide a measure of chemical similarity are strongly relevant in several fields of chemoinformatics as they allow to predict the molecular behavior and fate of structurally close compounds. One common application of chemical similarity measurements, based on the principle that similar molecules have similar properties, is the read-across approach, where an estimation of a specific endpoint for a chemical is provided using experimental data available from highly similar compounds. Results: This paper reports the comparison of multiple combinations of binary fingerprints and similarity metrics for computing the chemical similarity in the context of two different applications of the read-across technique. Conclusions: Our analysis demonstrates that the classical similarity measurements can be improved with a generalizable model of similarity. The proposed approach has already been used to build similarity indices in two open-source software tools (CAESAR and VEGA) that make several QSAR models available. In these tools, the similarity index plays a key role for the assessment of the applicability domain.
A GPU framework for parallel segmentation of volumetric images using discrete deformable models
(Springer, 2011-02) Schmid, Jerome; Iglesias Guitián, José Antonio; Gobbetti, Enrico; Magnenat-Thalmann, Nadia
Despite the ability of current GPU processors to treat heavy parallel computation tasks, its use for solving medical image segmentation problems is still not fully exploited and remains challenging. A lot of difficulties may arise related to, for example, the different image modalities, noise and artifacts of source images, or the shape and appearance variability of the structures to segment. Motivated by practical problems of image segmentation in the medical field, we present in this paper a GPU framework based on explicit discrete deformable models, implemented over the NVidia CUDA architecture, aimed for the segmentation of volumetric images. The framework supports the segmentation in parallel of different volumetric structures as well as interaction during the segmentation process and real-time visualization of the intermediate results. Promising results in terms of accuracy and speed on a real segmentation experiment have demonstrated the usability of the system.
A heat exchanger design for the separated window target of the EADF
(2000) Aragonese, Cosimo; Buono, Stefano; Fotia, Giorgio; Maciocco, Luca; Moreau, Vincent; Sorrentino, Luca
The spallation target of the Energy Amplifier Demonstration Facility (EADF) [1] is cooled by a liquid lead-bismuth eutectic (LBE), while the secondary coolant is a diathermic oil. The reasons for these choices have been extensively discussed in [2] and [3]. Here we present the design and the optimisation of a heat exchanger using these fluids, whose additional requirements are the need of fitting into the top of the annular downcomer section of the target and the minimisation of the pressure losses on the LBE side, allowing the use of natural convection for the circulation of the primary fluid. Heat exchanger working temperatures are between 250 and 180°C in the LBE side, and between 150 and 190°C in the oil side (cold fluid), while the power to be removed is up to 3 MW. We selected a bayonet-type heat exchanger, as suggested in [4] for the primary loop of the EADF vessel, which seems to be the most appropriate choice to satisfy all the requirements.

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