Jeremy A. Brown

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Dynamically Programmable Gate Arrays (DPGAs) represent a hybrid architecture lying between traditional FPGAs and SIMD arrays. Notably, these arrays can efficiently support computations where the function of the array elements needs to vary both among array elements during any single cycle and within any single array element over time. We describe our(More)
The results of a study of the three-dimensional vibration of two dry human skulls in response to harmonic excitation are presented. The vibratory response exhibits three distinct types of motion across the range of audible frequencies. At low frequencies below 1000 Hz, whole-head quasi-rigid motion is seen. At the middle frequencies between 1000 and 6000(More)
Morphometric analysis of 54 dry cervical spines from C3 to C7 (a total of 270 cervical vertebrae) and bilateral dissection of 10 anatomic specimen cervical spines were performed. The uncinate processes were significantly higher at C4 to C6 (5.8 +/- 1.1 mm to 6.1 +/- 1.3 mm) levels than at C3 or C7 levels. The anteroposterior diameter of the intervertebral(More)
STUDY DESIGN The authors measured the thickness and quality of occipital bone regions to determine screw placement during occipitocervical fusion and described the projection of the posterior dural venous sinuses. OBJECTIVE This study provides anatomic data relevant to areas of screw placement into the occiput during occipitocervical fixation. SUMMARY(More)
In the present study, the anatomic location of supraorbital and greater occipital nerves and their branches was quantitatively determined with regard to halo pin placement, and a safe zone for anterolateral and posterolateral halo pins was defined to minimize neurologic damage. The mean distance between the midline and the lateral branches of supraorbital(More)
The bone-anchored-hearing-aid (BAHA) transduces airborne sound into skull vibration. Current bilateral BAHA configurations, for sounds directly facing listeners, will apply forces that are in-phase with each other and directed roughly towards the center of the head. Below approximately 1000 Hz the two cochleae respond in approximately the same direction and(More)
Digital transmit and receive beamformers for a 45-MHz, 7-element annular array are described. The transmit beamformer produces 0- to 80-Vpp monocycle pulses with a timing error of less than +/-125 ps. Up to four adjustable transmit focal zones can be selected. The dynamic receive beamformer uses a variable frequency sampling technique in which the frequency(More)
HYPOTHESIS To illustrate the ability of high frequency ultrasound (HFUS) using a transducer array to demonstrate a variety of simulated clinical scenarios involving the ossicular chain. BACKGROUND HFUS (>20 MHz) is a relatively new area of ultrasonic imaging that provides an order of magnitude better image resolution than the conventional low-frequency(More)
Ultrasonic power transfer using piezoelectric devices is a promising wireless power transfer technology for biomedical implants. However, for sub-dermal implants where the separation between the transmitter and receiver is on the order of several acoustic wavelengths, the ultrasonic power transfer efficiency (PTE) is highly sensitive to the distance between(More)