PURPOSE To develop an intensity inhomogeneity algorithm for breast sonograms in order to assist visual identification and automatic delineation of lesion boundaries. METHODS The proposed algorithm was composed of two essential ideas. One was decomposing the region of interest (ROI) into foreground and background regions by a cell-based segmentation algorithm, called constrained fuzzy cell-bas...

Title of dissertation: Effect of Aggregate Inhomogeneity on Mechanical Properties of Asphalt Mixtures Haleh Azari, Doctor of Philosophy, 2005 Dissertation directed by: Professor Richard McCuen Department of Civil and Environmental Engineering Vertical and radial inhomogeneity of asphalt mixture components in laboratoryfabricated specimens have been of concern in asphalt mixture testing because ...

BACKGROUND Structural abnormalities of the common carotid artery (CCA), as assessed by ultrasound techniques, are related to cardiovascular outcome in dialysis patients. An increased intima media thickness (IMT) of the CCA may both represent a reaction to a haemodynamic burden as well as atherosclerosis. With a new ultrasound technique CCA-IMT and IMT-inhomogeneity, a novel parameter of spatial...

....................................................................................................................... iv INTRODUCTION ................................................................................................................ 1 CHAPTER 1 MAGNETIC RESONANCE INHOMOGENEITY CORRECTION................ 3 1.1 Magnetic Resonance Image Acquisition Process ............................

Purpose Susceptibility weighted imaging (SWI) based on GRE provides enhancement of susceptibility difference which is useful for visualization of vein, micro-hemorrhage and iron deposition. However, GRE suffers from the macroscopic B0 inhomogeneity due to air/tissue boundary and this effect is shown as SNR loss both in magnitude and phase. Previously, 3D z-shim multi-echo GRE (mGRE) pulse seque...

This study concentrates on the free pure radial vibrations of hollow spheres made of hypothetically functionally simple power rule graded materials having identical inhomogeneity indexes for both Young’s modulus and the density in an analytical manner. After offering the exact elements of the free vibration coefficient matrices for free-free, free-fixed, and fixed-fixed restraints, a parametric...

Changes in ow strain and mixture composition on the order of a ame time scale are characteristic of many practical combustion processes. Accurately predicting the unsteady reponse of burning to these changes requires detailed modeling of species transport and chemical kinetics. This thesis formulates a detailed one-dimensional computational model for arbitrary unsteady conditions of strain and ...

Tissue engineering of various musculoskeletal or cardiovascular tissues requires scaffolds with controllable mechanical anisotropy. However, native tissues also exhibit significant inhomogeneity in their mechanical properties, and the principal axes of anisotropy may vary with site or depth from the tissue surface. Thus, techniques to produce multilayered biomaterial scaffolds with controllable...

Love-type wave generation in a fiber-reinforced medium placed over an inhomogeneous orthotropic half-space is analysed. The upper and lower boundary surfaces of the fiber reinforced medium are periodically corrugated. Inhomogeneity of half-space is caused by variable density and variable shear modules. Displacement components for layer and half-space are derived by applying separable variable t...