Suchergebnisse

14 páginas, 4 figuras, 10 tablas ; Initially developed for tasks related to computer graphics, GPUs are increasingly being used for general purpose processing, including scientific and engineering applications. In this contribution, we have compared the performance of two graphics cards that belong to the parallel computing CUDA platform with two C++ and Java multi-threading implementations, using as an example of computation a brute-force attack on Hitag2, a well known remote keyless entry application. The results allow us to provide valuable information regarding the compared capabilities of the tested platforms and to confirm that such a weak encryption system could be broken in less than a day with medium cost equipment. ; This work has been partially supported by Ministerio de Econom´ıa, Industria y Competitividad (MINECO), Agencia Estatal de Investigaci´on (AEI), and Fondo Europeo de Desarrollo Regional (FEDER, UE) under project COPCIS, reference TIN2017-84844-C2-1-R, and by Comunidad de Madrid (Spain) under project CIBERDINE, reference S2013/ICE-3095-CM, also co-financed by European Union FEDER funds.

14 páginas, 4 figuras, 10 tablas ; Initially developed for tasks related to computer graphics, GPUs are increasingly being used for general purpose processing, including scientific and engineering applications. In this contribution, we have compared the performance of two graphics cards that belong to the parallel computing CUDA platform with two C++ and Java multi-threading implementations, using as an example of computation a brute-force attack on Hitag2, a well known remote keyless entry application. The results allow us to provide valuable information regarding the compared capabilities of the tested platforms and to confirm that such a weak encryption system could be broken in less than a day with medium cost equipment. ; This work has been partially supported by Ministerio de Econom´ıa, Industria y Competitividad (MINECO), Agencia Estatal de Investigaci´on (AEI), and Fondo Europeo de Desarrollo Regional (FEDER, UE) under project COPCIS, reference TIN2017-84844-C2-1-R, and by Comunidad de Madrid (Spain) under project CIBERDINE, reference S2013/ICE-3095-CM, also co-financed by European Union FEDER funds.

6 páginas, 3 figuras. Proceedings of the 2013 International Congress on Ultrasonics (ICU 2013). 2-5 may 2013, Singapore ; In the SAFT technique (Synthetic Aperture Focusing Technique) each element operates in pulse-echo mode, requiring only on e transmit/receive channel. The generated beam pattern can present grating lobes, even if the pitc h is half wavelength, which are related to image quality. By considering the instantaneous phase of the signals detected by each transducer, it is possible to estimate if the signal used in the delay-and-sum algorithm, for each combination of array element and image pixel, is due to a reflector or if it is noise, improving the contrast and reducing the grating lobes effects. ; The authors would like to thank the financial support from FAPESP (2010/02240-0, 2010/16400- 0), Capes and CNPq as well as the government of Spain (CICYT - DPI 2010 19376). ; Peer reviewed

6 páginas, 2 figuras, 4 tablas ; Developing new imaging methods needs to establish some proofs of concept before implementing them on real -time scenarios. Nowadays, the high computational power reached by multi-core CPUs and GPUs have driven the development of software-based beamformers. Taking this into account, a library for the fast generation of ultrasound images is presented. It is based on Synthetic Aperture Imaging Techniques (SAFT) and it is fast because of the use of parallel computing techniques. Any kind of transducers as well as SAFT techniques can be defined although it includes some pre-built SAFT methods like 2R -SAFT and TFM. Furthermore, 2D and 3D imaging (slicebased or full volume computation) is supported along with the ability to generate both rectangular and angular images. For interpolation, linear and polynomial schemes can be chosen. The versatility of the library is ensured by interfacing it to Matlab, Python and any programming language over different operating systems. On a standard PC equipped with a single NVIDIA Quadro 4000 (256 cores), the library is able to calculate 262,144 pixels in ≈ 105 ms using a linear transducer with 64 elements, and 2,097,152 voxels in ≈ 5 seconds using a matrix transducer with 121 elements when TFM is applied. ; This work has been supported by the Spanish Government and the University of Alcalá under projects DPI2010- 19376 and CCG2014/EXP -084, respectively. ; Peer reviewed