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Beginning in the fall of 1998 and continuing to the present, an assessment study has been in progress to determine the effectiveness of visualization modules used in a basic engineering class at the United States Air Force Academy (USAFA). This paper discusses the progression of this assessment study. Until recently, there has been a lack of content(More)
—This paper demonstrates a practical approach to developing a geometrically scalable thermal resistance model to optimize layout for improved electrical performance of high-power RF transistors. The model is developed using finite element-based simulations, which show very good agreement with measured results. The proposed modeling methodology pre-computes(More)
Wavelet packet analysis is a mathematical transformation that can be used to post-process images, for example, to remove image noise ("denoising"). At a very low signal-to-noise ratio (SNR <5), standard magnitude magnetic resonance images have skewed Rician noise statistics that degrade denoising performance. Since the quadrature images have approximately(More)
RATIONALE Sickle cell disease is an inherited blood disorder characterized by vasoocclusive crises. Although hypoxia and pulmonary disease are known risk factors for these crises, the mechanisms that initiate vasoocclusive events are not well known. OBJECTIVES To study the relationship between transient hypoxia, respiration, and microvascular blood flow(More)
Visually evoked potentials (VEPs) and micro magnetic resonance imaging (micro MRI) are widely used as noninvasive techniques for diagnosis of central nervous system (CNS) diseases, especially myelin diseases, such as multiple sclerosis. Here we use these techniques in tandem to validate the in vivo data in mouse models. We used the shiverer mutant mouse,(More)
This paper compares and contrasts recent nonlinear behavioral modeling techniques designed for microwave and RFIC applications which arise in radio and communication systems, and in the design of broad-band nonlinear components used for microwave instrumentation. These techniques include dynamic neural networks and nonlinear time series models in the(More)
Iron-induced cardiac dysfunction is a leading cause of death in transfusion-dependent anemia. MRI relaxation rates R2(1/T2) and R2*(1/T2*) accurately predict liver iron concentration, but their ability to predict cardiac iron has been challenged by some investigators. Studies in animal models support similar R2 and R2* behavior with heart and liver iron,(More)
MRI is gaining increasing importance for the noninvasive quantification of organ iron burden. Since transverse relaxation rates depend on iron distribution as well as iron concentration, physiologic and pharmacologic processes that alter iron distribution could change MRI calibration curves. This article compares the effect of three iron chelators,(More)
Three dimensional Magnetic Resonance Imaging (MRI) datasets are becoming increasingly important in clinical and research applications because of their inherent signal to noise (SNR) advantages, high resolution and isotropic voxels. Despite SNR advantages, some 3D acquisitions may be SNR-limited, particularly in MR microscopy. Historically, both classic(More)