Statistics of the gravitational force in various dimensions of space: from Gaussian to Levy laws

We discuss the distribution of the gravitational force created by a Poissonian distribution of field sources (stars, galaxies,...) in different dimensions of space d. In d=3, it is given by a Levy law called the Holtsmark distribution. It presents an algebraic tail for large fluctuations due to the contribution of the nearest neighbor. In d=2, it is given by a marginal Gaussian distribution intermediate between Gaussian and Levy laws. In d=1, it is exactly given by the Bernouilli distribution (for any particle number N) which becomes Gaussian for N>>1. Therefore, the dimension d=2 is critical regarding the statistics of the gravitational force. We generalize these results for inhomogeneous systems with arbitrary power-law density profile and arbitrary power-law force in a d-dimensional universe

GPCALMA, a mammographic CAD in a GRID connection

6 pages, 4 figures, to appear in CARS 2003 Proceedings, Computer Assisted Radiology and Surgery 17th International Congress and Exhibition, London, June 25-28, 2003Purpose of this work is the development of an automatic system which could be useful for radiologists in the investigation of breast cancer. A breast neoplasia is often marked by the presence of microcalcifications and massive lesions in the mammogram: hence the need for tools able to recognize such lesions at an early stage. GPCALMA (Grid Platform Computer Assisted Library for MAmmography), a collaboration among italian physicists and radiologists, has built a large distributed database of digitized mammographic images (at this moment about 5500 images corresponding to 1650 patients). This collaboration has developed a CAD (Computer Aided Detection) system which, installed in an integrated station, can also be used for digitization, as archive and to perform statistical analysis. With a GRID configuration it would be possible for the clinicians tele- and co-working in new and innovative groupings ('virtual organisations') and, using the whole database, by the GPCALMA tools several analysis can be performed. Furthermore the GPCALMA system allows to be abreast of the CAD technical progressing into several hospital locations always with remote working by GRID connection. We report in this work the results obtained by the GPCALMA CAD software implemented with a GRID connection

Video Biometric Surveillance and Forensic Image Analysis

In this paper, we describe two research projects involving the Department of Electrical and Electronic Engineering (DIEE) of the University of Cagliari. They are related to the applications of biometrics for environmental video-surveillance and forensic sciences. In the first one, entitled “Procedure for Object Recognition and Processing of Multi-Input Images� (PRiO), the DIEE people has been involved as consultant of the company Vitrociset S.p.A.. The second one, entitled “State of the art on methods and algorithms for automatic analysis of fingerprint images and for fake fingerprints identification�, is in the context of an agreement between DIEE and Scientific Investigation Office (Ra.C.I.S.) of “Arma dei Carabinieri� (the militia maintained by the Italian government for police duties). The PRiO project is focused on the development of an intelligent system of sensors for the control of wide reserved areas. The sensors can interact each others in order to capture the presence of living objects in the scene (cars or humans), tracking the subject identity after passing through a proximity biometric verification system, and to signal some unusual situations to a human operator. The system is also able to program some counter-measures on the basis of models managed by a tactical simulation software. The role of DIEE consists in the development of some fundamentals modules of the project: a proximity biometric verification systems based on faces and fingerprints, a module for ancillary information extraction from a tracked subject (height, gait speed), and also to discriminate between cars and humans into a scene. The Ra.C.I.S. project lies in the development of a set of software modules aimed to process and compare latent fingerprint images, and also a prototype module which helps the human expert to discriminate latent fingerprints released by a live finger from those released by a fake finger