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The Brigham Young University (BYU) Radio Astronomy group, in collaboration with Cornell University, the University of Massachusetts, and the National Radio Astronomy Observatory (NRAO), have developed a phased-array feed receiver with sufficient bandwidth and elements for basic scientific use. This paper summarizes the capabilities of this 20-MHz, 64-element FPGA-based system.
An implanted neural stimulator with closed loop control requires electrodes for stimulation pulses and recording neuron activity. Our system features arrays of 64 electrodes. Each electrode can be addressed through a cross bar switch, to enable it to be used for stimulation or recording. This electrode switch, a bank of low noise amplifiers with an integrated analog to digital converter, power conditioning...
Terrain relative navigation (TRN) offers a means to constrain absolute vehicle position and attitude without using a GPS receiver or star camera, such as for unmanned aerial vehicles or planetary landing spacecraft, using a pre-computed terrain database of distinctive landmarks in the operational environment. However, depending on the length of the planned trajectory, these terrain landmark databases...
This paper introduces a compact optical payload enabling vision-based navigation and hazard detection during terrestrial rocket flights. This payload, the Terrain-Relative Navigation & Descent Imager (TRNDI), serves as an add-on module for Draper Laboratory's GENIE Autonomous-GNC system. GENIE's inertial navigation system relies on GPS during terrestrial test flights, making it insufficient for...
The difficulty of understanding a financial institution's risk of default has been highlighted by multiple recent episodes in both the U.S. and in Europe. This paper describes a study on the empirical comparison of classification techniques for predictive ranking of the 12 month risk of default in banks. This work compares the scoring capabilities of different predictive models. The models compared...
Diabetic Retinopathy (DR) is a vascular disorder affecting the retina due to prolonged Diabetes. It can lead to sudden vision loss in advanced stages. Screening and routine monitoring is the most effective way of avoiding vision loss due to DR. Abramoff et al. developed and evaluated an automated DR screening system. One of the most important parts of this system, the information fusion module, combines...
In this paper we apply the random walk-based segmentation method to mesothelioma CT image datasets, aiming to establish an automatic segmentation routine that can provide volumetric assessments for monitoring progression of the disease and its treatments. We have validated the applicability of this method to our image data through a series of experimental trials, and demonstrated the superior performance...
We describe a novel method to segment the bladder wall in magnetic resonance imaging (MRI) to support the detection of disease, such as endometriosis, and for surgical planning. We segment the inner and outer wall boundary using T2- and T1-weighted MRI images, respectively. A new coupling technique for level sets is formulated and tested on 54 T2- and T1-weighted image pairs. A local phase based dimensionless...
Recently, Kadir and Brady proposed a method for estimating probability density functions (PDFs) for digital signals which they call the Nonparametric (NP) Windows method. The method involves constructing a continuous space representation of the discrete space and sampled signal by using a suitable interpolation method. NP Windows requires only a small number of observed signal samples to estimate...
In multidisciplinary team (MDT) meetings for colorectal and liver cancer, each patient case is reviewed while evidence, including digital image scans such as MRI and PET/CT, is presented by clinicians. Currently these images are projected onto a wall, limiting clinician interaction. While multi-touch and interactive tabletops have been used to enhance collaboration in various scenarios, some aspects...
Positron emission tomography (PET) is a molecular imaging technique which provides important functional information about the human body. However, thoracic PET images are often substantially degraded by respiratory motion, which adversely impacts on subsequent diagnosis. In this paper, a motion correction and attenuation correction method is proposed to correct for motion in respiratory gated PET...
W-band high power amplifiers offer important and enabling opportunities in radar, directed energy and communications including SATCOM applications. In this study, W-band microwave power modules (MPMs) combining low power monolithic microwave integrated circuit (MMIC) driver amplifiers and Solid State Vacuum Device (SSVD™) traveling wave tube (TWT) high power amplifiers are employed to provide high...
Magnetrons for civil marine radar applications have been manufactured on the e2v Chelmsford site since 1947. The earliest production was of the original S band wartime designs developed by the Radiation Laboratory at MIT but it was not long before engineers at the then English Electric Valve Company began making improvements. This paper traces the development of magnetrons for marine radar from the...
This paper reports a method that aims to quantify the changes of tumour vascular structure as a result of drug treatment. The measures we have investigated to date include: vessel radii, inter-branch lengths, tortuosity and branch angles. We show that the distribution of vessel radii is better modelled as a gamma distribution as opposed to the log-normal distribution asserted by other researchers...
The aim of this paper is to introduce effects well known to clinicians -but neglected to date- in the biomechanical modelling of breast malignant tumours. We develop a model of an isolated stellate breast tumour under mammographic compression forces. We study a range of reported mechanical properties, both linear elastic and hyperelastic. We also introduce different volumes of increased density/stiffness...
The detection of microcalcifications, reconstruction of clusters of microcalcifications and their subsequent classification into malignant and benign are important tasks in the early detection of breast cancer. Digital breast tomosynthesis (DBT) provides new opportunities in such tasks. By utilizing the multiple projections in DBT and using the geometry of DBT, we have developed an approach to them...
Our recent adaptation to PET of the method of Fitchard et al., for rigid body registration of CT sinograms enables motion between two temporal frames of PET data to be estimated and corrected prior to reconstruction. This avoids both the computation required by multiple reconstructions and the need to make choices regarding reconstruction methods that influence the images produced, and potentially...
We present a feature point detection algorithm which we use for non-rigid registration, illustrated for breast images (mammography, MRI). By associating the continuous intrinsic dimensionality of image structure with the output of a scale saliency algorithm, breast boundary points can be separated from internal feature points. Correspondences established for the breast boundary and internal feature...
Colorectal cancer is the third most common cancer diagnosed in men and women. Generally surgery is by total excision of the mesorectum (TME), though it often has a poor outcome due to affected lymph nodes close to the resection boundary. Advancements in diagnosis and treatment of colorectal cancer require integration of information from different sources such as pathology macroscopic and microscopic...
We develop a novel simultaneous reconstruction and registration algorithm for limited view transmission tomography. We derive a cost function using Bayesian probability theory, and propose a similarity metric based on the explicit modeling of the joint histogram as a sum of bivariate clusters. The resulting algorithm shows a robust mitigation of the data insufficiency problem in limited view tomography...
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