388 research outputs found

    GPCALMA: a Grid Approach to Mammographic Screening

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    The next generation of High Energy Physics experiments requires a GRID approach to a distributed computing system and the associated data management: the key concept is the "Virtual Organisation" (VO), a group of geographycally distributed users with a common goal and the will to share their resources. A similar approach is being applied to a group of Hospitals which joined the GPCALMA project (Grid Platform for Computer Assisted Library for MAmmography), which will allow common screening programs for early diagnosis of breast and, in the future, lung cancer. HEP techniques come into play in writing the application code, which makes use of neural networks for the image analysis and shows performances similar to radiologists in the diagnosis. GRID technologies will allow remote image analysis and interactive online diagnosis, with a relevant reduction of the delays presently associated to screening programs.Comment: 4 pages, 3 figures; to appear in the Proceedings of Frontier Detectors For Frontier Physics, 9th Pisa Meeting on Advanced Detectors, 25-31 May 2003, La Biodola, Isola d'Elba, Ital

    A Computer Aided Detection system for mammographic images implemented on a GRID infrastructure

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    The use of an automatic system for the analysis of mammographic images has proven to be very useful to radiologists in the investigation of breast cancer, especially in the framework of mammographic-screening programs. A breast neoplasia is often marked by the presence of microcalcification clusters and massive lesions in the mammogram: hence the need for tools able to recognize such lesions at an early stage. In the framework of the GPCALMA (GRID Platform for Computer Assisted Library for MAmmography) project, the co-working of italian physicists and radiologists built a large distributed database of digitized mammographic images (about 5500 images corresponding to 1650 patients) and developed a CAD (Computer Aided Detection) system, able to make an automatic search of massive lesions and microcalcification clusters. The CAD is implemented in the GPCALMA integrated station, which can be used also for digitization, as archive and to perform statistical analyses. Some GPCALMA integrated stations have already been implemented and are currently on clinical trial in some italian hospitals. The emerging GRID technology can been used to connect the GPCALMA integrated stations operating in different medical centers. The GRID approach will support an effective tele- and co-working between radiologists, cancer specialists and epidemiology experts by allowing remote image analysis and interactive online diagnosis.Comment: 5 pages, 5 figures, to appear in the Proceedings of the 13th IEEE-NPSS Real Time Conference 2003, Montreal, Canada, May 18-23 200

    Automated detection of lung nodules in low-dose computed tomography

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    A computer-aided detection (CAD) system for the identification of pulmonary nodules in low-dose multi-detector computed-tomography (CT) images has been developed in the framework of the MAGIC-5 Italian project. One of the main goals of this project is to build a distributed database of lung CT scans in order to enable automated image analysis through a data and cpu GRID infrastructure. The basic modules of our lung-CAD system, consisting in a 3D dot-enhancement filter for nodule detection and a neural classifier for false-positive finding reduction, are described. The system was designed and tested for both internal and sub-pleural nodules. The database used in this study consists of 17 low-dose CT scans reconstructed with thin slice thickness (~300 slices/scan). The preliminary results are shown in terms of the FROC analysis reporting a good sensitivity (85% range) for both internal and sub-pleural nodules at an acceptable level of false positive findings (1-9 FP/scan); the sensitivity value remains very high (75% range) even at 1-6 FP/scanComment: 4 pages, 2 figures: Proceedings of the Computer Assisted Radiology and Surgery, 21th International Congress and Exhibition, Berlin, Volume 2, Supplement 1, June 2007, pp 357-35

    S.T.R.E.S.S. : Stress Testing and Reverse Engineering for System Security

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    In modern wireless networks the functions included into layer II have to deal with complex problems, such as security and access control, that were previously demanded to upper layers. This growing complexity led some vendors to implement layer II primitives directly in software, e.g. IEEE 802.11i has been largely distributed as a software patch to be used with legacy 802.11b/g hardware. In any extremely complex software the likelihood of committing errors during the implementation raises, and it is well known that software bugs can lead to instability of the system and possibly to security vulnerability. Software bugs are the most common cause of successful attacks against any kind of network and represent a real plague for system administrators. Stress test is a widely used methodology to find and eliminate software bugs. In this paper we present a platform to perform a stress test of generic network protocols implementations but especially optimized for Layer II stress tests, that present specific problems. With our approach a generic network protocol described with ABNF language can be tested transmitting arbitrary frame sequences and interpreting the responses to verify consistence with the communication standard used. Our platform can interact dynamically with the tested machine (an access point, a router etc.) to verify its robustness and its compliance with the standard. Experiments confirmed the validity of our approach both as a stress test technique for system under development and as a reverse engineering technique for interaction with closed source system

    PS-CDMA: spreading signals for CDMA designed in the frequency domain using perfect sequences

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    A dynamic channel allocation technique based on Hopfield neural networks

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    Hopfield neural networks for dynamic channel allocation in mobile communication systems

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    Article going forward from b to a? Proposals for the eurozone crisis

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    After reviewing the main determinants of the current Eurozone crisis, this paper discusses the feasibility of introducing fiscal currencies as a way to restore fiscal space in peripheral countries, such as Greece, which have so far adopted austerity measures in order to abide by their commitments with Eurozone institutions and the IMF. We show that the introduction of fiscal currencies would speed up the recovery, without violating the rules of Eurozone Treaties. At the same time, these processes could help the transition of the euro from its current status of single currency to a status of “common clearing currency” along the lines proposed by Keynes at Bretton Woods as a system of international settlements. Eurozone countries could therefore move from “Plan B” aimed at addressing member state domestic problems, to a “Plan A” of a better European monetary system

    Spectral splitting photovoltaics using perovskite and wideband dye-sensitized solar cells

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    The extension of the light absorption of photovoltaics into the near-infrared region is important to increase the energy conversion efficiency. Although the progress of the lead halide perovskite solar cells is remarkable, and high conversion efficiency of >20% has been reached, their absorption limit on the long-wavelength side is similar to 800 nm. To further enhance the conversion efficiency of perovskite-based photovoltaics, a hybridized system with near-infrared photovoltaics is a useful approach. Here we report a panchromatic sensitizer, coded DX3, that exhibits a broad response into the near-infrared, up to similar to 1100 nm, and a photocurrent density exceeding 30 mA cm(-2) in simulated air mass 1.5 standard solar radiation. Using the DX3-based dye-sensitized solar cell in conjunction with a perovskite cell that harvests visible light, the hybridized mesoscopic photovoltaics achieved a conversion efficiency of 21.5% using a system of spectral splitting.open0
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