P-arch
Not a member yet
966 research outputs found
Sort by
Un sistema multiprocessore per la simulazione della chirurgia sull'osso temporale
Get PDFNel presente articolo si presenta un simulatore per l’addestramento alla chirurgia dell’osso temporale. Il sistema si basa su modelli volumetrici direttamente derivati da dati 3D di TAC e MR. Il ritorno di sensazioni in tempo reale viene fornito all’utente per mezzo di tecniche di rendering volumetrico e di modellazione di sensazioni aptiche. I vincoli nelle prestazioni imposti dal sistema percettivo umano sono soddisfatti sfruttando il parallelismo attraverso il disaccoppiamento della simulazione su una piattaforma
di PC multi-processore. In quest’articolo, vengono descritti in dettaglio i componenti del sistema e lo stato attuale dell’integrazione dei medesimi
Head and hand tracking devices in virtual reality
No full textThis short introduction to head and hand tracking devices summarizes the characteristics of some of the technologies most relevant to medical application and presents the configuration chosen in three representative test beds.287-29
Mastoidectomy simulation with combined visual and haptic feedback
Get PDFMastoidectomy is one of the most common surgical procedures relating to the petrous bone. In this paper we describe our preliminary results in the realization of a virtual reality mastoidectomy simulator. Our system is designed to work on patient-specific volumetric object models directly derived from 3D CT and MRI images. The paper summarizes the detailed task analysis performed in order to define the system requirements, introduces the architecture of the prototype simulator, and discusses the initial feedback received from selected end users.17-2
Modeling NAPL dissolution and biodegradation interactions: effect of toxicity and biomass growth limitations
No full textThis work focuses on some aspects of the interactions between NAPL dissolution, molecular diffusion and biodegradation processes. Starting from a test problem based on a real field scenario, a one-dimensional model is set up. A number of simulations are run using different biomass distributions, varying diffusion coefficients and biological kinetic rates. Results indicate that under ideal conditions biomass distribution along the column does not make a real difference in terms of total amount of dissolved oil degraded. Results change dramatically when introducing limitations in the growth of biomass and the effects of toxicity into the model. Both of these are modelled as functions for which some threshold or bounding levels are specified. In particular, toxicity function is derived from some phenomenogical considerations, since, at least to the author's knowledge, no documentation in the literature is available in this regard. Constrained biomass growth and contaminant toxicity have been found to yield results consistent with field data on contaminant distribution. This would support our presumption that biomass growth constraint and toxicity play a major role in reducing natural attenuation efficiency.859-86
Adattamento e parametrizzazione del modello numerico: sito di Portoscuso
Get PDFIl presente rapporto fa parte degli elaborati tecnici della III fase (Attuazione) del Progetto PST/MURST Tecnologie avanzate perla gestione delle risorse idriche: software per la modellazione ambientale. Nel documento si descrivono le fasi di adattamento e parametrizzazione del programma di calcolo CODESA-3D (Gambolati et al. 1999, Lecca) per l’implementazione del modello numerico tridimensionale dell’acquifero costiero del sito di Portoscuso (Sardegna sud-occidentale). Obiettivo generale di questa parte del Progetto è la simulazione, tramite il modello numerico, dei fenomeni di trasporto di inquinanti inerti, assimilabili come comportamento ai sali marini. Il sistema acquifero della piana di Portoscuso è stato oggetto di diversi studi. La zona è interessata da un grosso polo industriale di zone estrattive di minerali. Per la predisposizione dei dati di input del modello ci si è avvalsi in modo sostanziale delle tecnologie informatiche GIS, attraverso la costituzione e l’aggiornamento di un database cartografico e alfanumerico (Cau e Muscas 2001, Muscas et al. 2001) e lo sviluppo di interfacce software per l’integrazione dei diversi sistemi informatici (GIS, generatori di griglie di calcolo, modello numerico, etc. ) descritte nell’elaborato della III fase “Interfacciamento GIS-Modello”. Questo rapporto, inoltre, fa riferimento agli elaborati “Descrizione del GIS-Database implementato” e “Analisi dei dati” (Muscas e Cau, 2002) della fase III e risulta a sua volta propedeutico all’elaborato “Descrizione delle prove di calibrazione e validazione” della presente fase
IERAPSI
No full textIERAPSI provides a novel approach to computerised image-guided surgical planning. The project aims at providing an environment for visualising and interacting with the anatomy and pathology demonstrated by advanced imaging methods and VR techniques. At the same time IERAPSI will allow rehearsal of procedures on an individual patient and the development of training systems based on individual patient's variations in anatomy and pathology.Completato€ 503.60
PEelse: a 2D parallel spectral code for linear elastic analysis of seismic wave propagation. Implementation of seismic sources (plane wave and seismic moment tensor), absorbing boundaries and damping factor
Get PDFPEelse2D is a spectral element, parallel, computer program for the analysis of complex 2D
structure system, subject to transient dynamic loading conditions. PEelse2D is developed by the
CRS4 team. The co-operation between the CRS4 and the Technical school of Milan (Department of
Structural Engineering) is intended to equip the program of typical tools necessary for the
simulation of seismic wave propagation into linear visco-elastic medium.
The goal of the present report is to present the results obtained during the period 15 July – 14 September 2002, on three important topics: portability of PEelse2D; functionality of PEelse2D; implementation of the necessary tools for the analysis in the seismic wave field: most common sources in the seismic field (plane wave in the form of Ricker wavelet and seismic moment tensor (Madariaga, 1983)); internal soil dissipation as described by Kosloff and Kosloff (1986); Absorbing boundaries condition (Stacey, 1988)
Assessment of turbulence models for heavy liquid metals in computational fluid dynamics
Get PDFA summary and analysis of the results obtained from work-packages 1-6 of the ASCHLIM project is presented in this document, with the aim of defining the performances and shortcomings of CFD turbulence models currently adopted for the simulation of Heavy Liquid Metals flows in nuclear applications.
Two classes of problems are analysed, one related to liquid metals physical characteristics (low Prandtl number) and one related to the flow morphology in typical ADS applications. Concerning the first class, some drawbacks were found in the use of wall-functions for HLM flows.
In fact, thermal wall-functions currently implemented in commercial CFD codes are in general unsuitable for HLM flows, unless the first grid point lays in the thermal sublayer y+ < 70 ÷ 100. It was also proved that the Reynolds analogy is not applicable for very low Peclet number flows (~100). However, correct results were obtained for higher Pe (~1000), even using a constant value for the turbulent Prandtl number (0.9).
Due to the lack of experimental measurements of turbulence quantities, it was not possible to draw strong conclusions concerning the second class of problems. However, results confirmed the capability of two-equation models to give a reasonably good prediction of the main flow characteristics in complex flow morphology typical of spallation-targets applications. Higher order models, both for momentum and heat turbulence transport, should be used in cases where turbulence anisotropy is important
Laboratory setup status report
Get PDFIn this document is presented the activities regarded the hardware and software upgrade and maintenance of the Laboratory for Advanced Planning and Simulation project (LAPS) and the software development activities in the framework of the development of tools for geometric reconstruction of carotid arteries