A priori mesh grading for the numerical calculation of the head-related transfer functions.

Head-related transfer functions (HRTFs) describe the directional filtering of the incoming sound caused by the morphology of a listener's head and pinnae. When an accurate model of a listener's morphology exists, HRTFs can be calculated numerically with the boundary element method (BEM). However, the general recommendation to model the head and pinnae with at least six elements per wavelength renders the BEM as a time-consuming procedure when calculating HRTFs for the full audible frequency range.

Numerical calculation of listener-specific head-related transfer functions and sound localization: Microphone model and mesh discretization.

Head-related transfer functions (HRTFs) can be numerically calculated by applying the boundary element method on the geometry of a listener's head and pinnae. The calculation results are defined by geometrical, numerical, and acoustical parameters like the microphone used in acoustic measurements. The scope of this study was to estimate requirements on the size and position of the microphone model and on the discretization of the boundary geometry as triangular polygon mesh for accurate sound localization.

Tuning of vocal tract model parameters for nasals using sensitivity functions.

Determining the cross-sectional areas of the vocal tract models from the linear predictive coding or autoregressive-moving-average analysis of speech signals from vowels has been of research interest for several decades now. To tune the shape of the vocal tract to given sets of formant frequencies, iterative methods using sensitivity functions have been developed. In this paper, the idea of sensitivity functions is expanded to a three-tube model used in connection with nasals, and the energy-based sensitivity function is compared with a Jacobian-based sensitivity function for the branched-tube model.

Fast multipole boundary element method to calculate head-related transfer functions for a wide frequency range.

Head-related transfer functions (HRTFs) play an important role in spatial sound localization. The boundary element method (BEM) can be applied to calculate HRTFs from non-contact visual scans. Because of high computational complexity, HRTF simulations with BEM for the whole head and pinnae have only been performed for frequencies below 10 kHz.

Sentinel lymph node detection with large human serum albumin colloid particles in breast cancer.

Detection of metastatic involvement of lymph nodes is essential for management and prognostic evaluation in breast cancer patients. The success of lymphatic mapping depends on identifying the sentinel lymph node(s) draining the primary tumour. However, when mapping is performed with a radiocolloidal agent, the number of hot lymph nodes varies with the agent and its size, among other factors.