Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Modeling Breast Ultrasound; on the Applicability of Commonly Made Approximations

Taskin U., Ozmen N., Gemmeke H., van Dongen K. W. A.

Archives of Acoustics

2018

Vol. 43, No. 3

425--435

To design breast ultrasound scanning systems or to test new imaging methods, various computer models are used to simulate the acoustic wave field propagation through a breast. The computer models vary in complexity depending on the applied approximations. The objective of this paper is to investigate how the applied approximations affect the resulting wave field. In particular, we investigate the importance of taking three-dimensional (3-D) spatial variations in the compressibility, volume density of mass, and attenuation into account. In addition, we compare four 3-D solution methods: a full-wave method, a Born approximation method, a parabolic approximation method, and a ray-based method. Results show that, for frequencies below 1 MHz, the amplitude of the fields scattering off the compressibility or density contrasts are at least 24 dB higher than the amplitude of the fields scattering off the attenuation contrasts. The results also show that considering only speed of sound as a contrast is a valid approximation. In addition, it is shown that the pressure field modeled with the full-wave method is more accurate than the fields modeled using the other three methods. Finally, the accuracy of the full-wave method is location independent whereas the accuracy of the other methods strongly depends on the point of observation.

Grid Technologies for High Throughput Data Acquisition

Sutter M., Jejkal T., Stotzka R., Hartmann V., Hardt M., Gemmeke H.

Computational Methods in Science and Technology

2009

Vol. 15, nr 1

105-115

The Grid is an upcoming technology, providing access to an unimaginable amount of storage and computation resources. In the final stage of the Grid nearly every computer worldwide offers its free capacities to the Grid, which gives access to the resources as simple as getting electricity from a power outlet. As process data processing has very high resource demands, growing up rapidly from project to project, the Grid offers the capabilities to fulfil the requirements for upcoming process data processing projects. This paper evaluates the already existing remote control software packages to be used in process data processing projects, explains the demands for developing a high throughput data acquisition system with the introduced requirements, shows the advantages of using Grid technologies and proposes an architecture for developing such a system.