CRS4 Atti di convegno

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https://hdl.handle.net/11050/50

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A large scale interactive holographic display
(IEEE, 2006) Agocs, Tibor; Balogh, Tibor; Forgacs, Tamas; Bettio, Fabio; Gobbetti, Enrico; Zanetti, Gianluigi
Our work focuses on the development of interactive multi-user holographic displays that allow freely moving naked eye participants to share a three dimensional scene with fully continuous, observer independent, parallax. Our approach is based on a scalable design that exploits a specially arranged array of projectors and a holographic screen. The feasibility of such an approach has already been demonstrated with a working hardware and software 7.4M pixel prototype driven at 10-15Hz by two DVI streams. In this short contribution, we illustrate our progress, presenting a 50M pixel display prototype driven by a dedicated cluster hosting multiple consumer level graphic cards.
A scalable holographic display for interactive graphics applications
(2005) Balogh, Tibor; Forgacs, Tamas; Balet, Olivier; Bouvier, Eric; Bettio, Fabio; Gobbetti, Enrico; Zanetti, Gianluigi
We present a scalable holographic system design targeting multi-user interactive computer graphics applications. The display device is based on back-projection technology and uses a specially arranged array of microdisplays and a holographic screen. The display is driven by DVI streams generated by multiple consumer level graphics boards and decoded in real-time by image processing units that feed the optical modules at high refresh rates. An OpenGL compliant library running on a client PC redefines the OpenGL behavior to multicast graphics commands to server PCs, where they are reinterpreted in order to implement holographic rendering. The feasibility of the approach is demonstrated with a working hardware and software 7.4M pixel prototype driven at 10-15Hz by two DVI streams.
An ontology-based content management system for a dynamic operating context: issues and prototype evaluation
(Academic Conferences International, 2006) Agelli, Maurizio; Colucci, Felice
Content management systems are very useful tools for organizing and sharing information resources and may considerably benefit from using ontology-based description schemes. Ontologies set a common ground for resource acquisition, enabling different users to share a common view of a knowledge domain, and may considerably enhance the search paradigms by exploiting semantic relationships between concepts. However, ontologies may evolve since they reflect knowledge schemes that are by nature dynamic. Moreover this evolution should be the result of a collaborative process of ontology maintenance. These and other issues are addressed in the present work and some practical solutions are proposed. Also, a very simple prototype implementation of an ontology-based content management system is described. Finally, the results of a short experimentation of this prototype within a small community are presented.
Catheter insertion simulation with combined visual and haptic feedback
(1999-05) Zorcolo, Antonio; Gobbetti, Enrico; Pili, Piero; Tuveri, Massimiliano
We have developed an experimental catheter insertion system supporting head-tracked stereoscopic viewing of volumetric reconstruction registered with direct haptic 3D interaction. The system takes as input patient data acquired with standard medical imaging modalities and regards it as a visual and haptic environment whose parameters are defined using look-up tables. By means of a mirror, the screen seems to be positioned like a surgical table providing the impression of looking down at the patient in a natural way. Co-registering physical and virtual spaces beforehand means that the patient appears at a fixed physical positionj on the surgical table and inside the workspace of the PHANToM device which controls catheter insertion. During the insertion procedure the system provides perception of the force of penetration and positional deviation of the inserted catheter.
Collaborative immersive visualization without goggles -- experiences in developing a holographics display system for medical applications
(2005-11) Bettio, Fabio; Frexia, Francesca; Gobbetti, Enrico; Pintore, Giovanni; Zanetti, Gianluigi; Balogh, Tibor; Forgacs, Tamas; Agocs, Tibor; Bouvier, Eric
In this contribution, we report on the development of a novel holographic display technology that targets multiple freely moving naked eye viewers and of a collaborative medical application prototype that aims at exploiting this technology to provide medical specialists with a truly interactive 3D collaborative environment for diagnostic discussions and/or pre-operative planning.
Compact gml: merging mobile computing and mobile cartography
(2004) Piras, Andrea; Demontis, Roberto; De Vita, Emanuela; Sanna, Stefano
The use of portable devices is moving from "Wireless Applications", typically implemented as browsing-on-the-road, to "Mobile Computing", which aims to exploit increasing processing power of consumer devices. As users get connected with smartphones and PDAs, they look for geographic information and location-aware services. While browser-based approaches have been explored (using static images or graphics formats such as Mobile SVG), a data model tailored for local computation on mobile devices is still missing. This paper presents the Compact Geographic Markup Language (cGML) that enables design and development of specific purpose GIS applications for portable consumer devices where a cGML document can be used as a spatial query result as well.
DART: the distributed agent based retrieval toolkit
(2007) Angioni, Manuela; Demontis, Roberto; Deriu, Massimo; De Vita, Emanuela; Lai, Cristian; Marcialis, Ivan; Pintus, Antonio; Piras, Andrea; Soro, Alessandro; Tuveri, Franco
The technology of search engines is evolving from indexing and classification of web resources based on keywords to more sophisticated techniques which take into account the meaning and the context of textual information and usage. Replying to query, commercial search engines face the user requests with a large amount of results, mostly useless or only partially related to the request; the subsequent refinement, operated downloading and examining as much pages as possible and simply ignoring whatever stays behind the first few pages, is left up to the user. Furthermore, architectures based on centralized indexes, allow commercial search engines to control the advertisement of online information, in contrast to P2P architectures that focus the attention on user requirements involving the end user in search engine maintenance and operation. To address such wishes, new search engines should focus on three key aspects: semantics, geo-referencing, collaboration/distribution. Semantic analysis lets to increase the results relevance. The geo-referencing of catalogued resources allows contextualisation based on user position. 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. In this paper, we describe the studies, the concepts and the solutions developed in the DART project to introduce these three key features in a novel search engine architecture.
Defining a distributed agile methodology for an open source scenario
(2005-07) Angioni, Manuela; Sanna, Raffaella; Soro, Alessandro
In this paper we propose and describe an agile methodology for distributed development (MADD - Methodology for Agile Distributed Development). In particular, it's illustrated a set of best practices to apply in a distributed and agile context, chosen on the base of their impact software quality and team interoperation. Beyond the proposed methodology, we show the results of a survey that we submitted to various contributors of Open Source projects. The survey has been of support to the definition of the MADD, helping to more understand and estimate if, how and how much agile practices and values are already present in the OS world, that today represents one of the most emblematic examples of distributed development. The MADD methodology will be adopted on a software development project at the University of Cagliari (Italy), by a group of students that will work like an Open Source community.
Design of the lhc beam dump entrance window
(European Physical Society Accelerator Group, 2006) Veness, R.; Goddard, B.; Mathot, S. J.; Presland, A.; Massidda, Luca
7 TeV proton beams from the LHC are ejected through a 600 m long beam dump transfer line vacuum chamber to a beam dump block. The dump block is contained within an inert gas-filled vessel to prevent a possible fire risk. The dump vessel and transfer line are separated by a 600 mm diameter window, which must withstand both the static pressure load and thermal shock from the passage of the LHC beam. In a previous paper [1] the functional requirements and conceptual design of this window were outlined. This paper describes the analysis leading to the final design of the window. The choice of materials is explained and tests performed on the prototype window are summarized.
Dynamic stresses in the lhc tcds diluter from 7tev beam loading
(European Physical Society Accelerator Group, 2006) Goddard, B.; Presland, A.; Weterings, W. j. M.; Massidda, Luca
Photo repair and 3d structure from flatbed scanners
(2009-02) Pintus, Ruggero; Malzbender, Thomas; Wang, Oliver; Bergman, Ruth; Nachlieli, Hila; Ruckenstein, Gitit
We introduce a technique that allows 3D information to be captured from a conventional flatbed scanner. The technique requires no hardware modification and allows untrained users to easily capture 3D datasets. Once captured, these datasets can be used for interactive relighting and enhancement of surface detail on physical objects. We have also found that the method can be used to scan and repair damaged photographs. Since the only 3D structure on these photographs will typically be surface tears and creases, our method provides an accurate procedure for automatically detecting these flaws without any user intervention. Once detected, automatic techniques, such as infilling and texture synthesis, can be leveraged to seamlessly repair such damaged areas. We first present a method that is able to repair damaged photographs with minimal user interaction and then show how we can achieve similar results using a fully automatic process.
Pseudo-holographic device elicits rapid depth cues despite random-dot surface masking
(Pion, 2007) Brelstaff, Gavin; Agus, Marco; Gobbetti, Enrico; Zanetti, Gianluigi
Experiments with random-dot masking demonstrate that, in the absence of cues mundanely available to 2-D displays (object occlusion, surface shading, perspective foreshortening, and texture gradients), Holografika's large-screen multi-projector video system (COHERENT-IST-FP6-510166) elicits useful stereoscopic and motion-parallax depth cues, and does so in under 2 s. We employed a simplified version of Julesz's (c. 1971) famous spiral ramp surface: a 3-layer cylindrical wedding-cake--via an openGL model that subjects viewed along its concentric axis. By adjusting its parameters, two sets of model-stimuli were rendered: one with a uniform large field of depth and one where the field was effectively flat. Each of eleven, pre-screened, subjects completed four experiments, each consisting of eight trials in a 2IFC design whereby they indicated in which interval they perceived the greatest field of depth. The experiments tested one-eye static, one-eye head-swaying, two-eye static, and two-eye head-swaying observation--in that order. Scores improved also in that order.
Simulating Populations in Massive Urban Environments
(2008) Balet, Olivier; Duysens, Jerome; Comptdaer, Jerome; Gobbetti, Enrico; Scopigno, Roberto
The United Nations recently reported that the global proportion of urban population reached 49% in 2005 and that 60% of the global population is expected to live in cities by 2030. Urbanised areas are extremely vulnerable to all sorts of threats. Indeed, the combination of heavy population concentrations, critical infrastructures and built environments make it possible for environmental, industrial or man-made incidents to rapidly escalate into major disorders. Recent events have forcefully demonstrated that authorities at all levels of government turn out to be inadequately prepared for the intricacies and dilemmas of disasters in large urban environments. Therefore, innovative tools are needed to assist them in the studies, planning and inter-organizational preparation efforts, enabling to understand vulnerabilities and security issues, define and assess crisis management procedures, and train personnel. The CRIMSON research project has been funded by the European Commission in the field of Security Research to address this challenging need by researching, implementing and validating an innovative framework combining the latest virtual reality and simulation technologies. For that purpose, several technological challenges have been tackled by an international team of researchers, industrials and users, and important advances have been made in the following fields.
The spectral element method as an effective tool for solving large scale dynamic soil-structure interaction problems
(Earthquake Engineering Research Institute, 2006) Stupazzini, Marco; Zambelli, C.; Massidda, Luca; Paolucci, R.; Maggio, Fabio; di Prisco, C.
The spectral element method (SEM) is a powerful numerical technique naturally suited for wave propagation and dynamic soil-structure interaction (DSSI) analyses. A class of SEM has been widely used in the seismological field (local or global seismology) thanks to its capability of providing high accuracy and allowing the implementation of optimized parallel algorithms. We illustrate inthis contribution how the SEM can be effectively used also for the numerical analysis of DSSI problems, with reference to the 3D seismic response of a railway viaduct in Italy. This numerical analysis includes the combined effect of: a) strong lateral variations of soil properties; b) topographic amplification; c) DSSI; d) spatial variation of earthquake ground motion in the structural response. Some hints on the work in progress to effectively handle nonlinear problems with SEM are also given.

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