Manifolds (Mathematics) Geodesics (Mathematics) Space and time.
We investigate weak and strong refocusing of light rays in a space-time and related concepts. A strongly causal space-time ( X^ n +1 , g ) is emphstrongly refocusing at x ∈ X if there is a point y ≠ x such that all null-geodesics through y pass...
Stark-geometry photorefractive multiple quantum well (PR-MQW) spatial light modulators (SLMs) show promise for several optoelectronic applications such as high-speed image correlation and real-time 3-D holographic imaging. Their performance is...
Large scale systems -- Mathematical models. Digital computer simulation. Parallel processing (Electronic computers). Computer algorithms.
Modeling real-world large-scale systems is inherently challenging due to their size and complexity. Detailed simulation of large-scale models requires tremendous amounts of computing power and memory space. Parallel discrete-event simulation...
We begin with a result on the refocussing of null geodesics in space-times. We show that all oriented refocussing 2-dimensional Lorentz manifolds are also strongly refocussing. We also introduce a theory of virtual Legendrian knots. We show that...
Three-dimensional imaging in medicine -- Mathematical models. ; Stereoencephalotomy.
In the past, clinicians skilled at image-guided neurosurgery have relied solely on pre-operative scans for their navigational information. Often in the course of surgery, tissue is purposely retracted/resected or inadvertently moved resulting in a...
Plasma instabilities. ; Ionospheric electron density. ; Ionosphere.
As a result of an unstable plasma stratification the nighttime equatorial ionosphere is subject to a variety of plasma instabilities known commonly as equatorial spread-F. In its fully developed form spread-F consists of large wedges of depleted...
In this work we investigate the quantum dynamics of three different configurations of nonlinear cavity systems. We begin by carrying out a quantum analysis of a dc superconducting quantum interference device (SQUID) mechanical displacement detector...
Microwave imaging (MI) is based on recovering dielectric properties (permittivity and conductivity) of materials. Over the last two decades, MI has attracted increasing interests in biomedical applications, in particular, for breast cancer...
At the heart of computer games and computer generated films lies 3D content creation. A student wanting to learn how to create and edit 3D meshes can quickly find thousands of videos explaining the workflow process. These videos are a popular...
Casimir effect. Zero-point field. Electric conductivity. Quantum electrodynamics.
The Casimir force arises from an alteration of boundary condition in vacuum and is often regarded as a manifestation of quantum zero point energy. Considerable progress has been made in the last decade with an impressive achievement of experimental...
Medical imaging methods have become increasingly important in diagnosing diseases and assisting therapeutic treatment. In particular, early detection of breast cancer is considered as a critical factor in reducing the mortality rate of women....
Earlier work has suggested that various neurological or neuropsychiatric disorders may result in characteristic spatial patterns in brain activation, potentially allowing their detection from maps of brain activity under different conditions....
The accelerated expansion of space in the Universe has been known for two decades. However, finding a plausible theory that describes this expansion is more difficult: Taking general relativity for granted requires us to stipulate the existence of...
Recent technological advances have fostered the emergence of Wireless Sensor Networks (WSNs), which consist of tiny, wireless, battery-powered nodes that are expected to revolutionize the ways in which we understand and construct complex physical...
In this thesis, we present different approaches to tying knots using robots by enforcing different types of constraints. We attack the problem from three different directions; mechanical design, motion planning with simple control strategies, and...
Magnetic fields at all scales are prevalent in our universe. However, current cosmological models predict that initially the universe was bereft of large-scale fields. Standard magnetohydrodynamics (MHD) does not permit magnetogenesis; in the MHD...
Brain -- Tomography. Magnetic resonance imaging -- Brain. Near infrared spectroscopy. Image processing -- Digital techniques.
Diffuse optical tomography (DOT) using near infrared (NIR) light has become a promising modality because it has the capability to non-invasively quantify oxygen saturation and hemoglobin content with potentially high temporal resolution and...
Calanus finmarchicus -- Georges Bank. ; Calanus finmarchicus -- Maine Gulf of. ; Calanus finmarchicus -- North Atlantic Ocean.
Calanus finmarchicus, a kind of marine zooplankton, plays an important ecological role throughout the North Atlantic. Striking seasonal variations exist in its abundance and distribution in the Gulf of Maine/Georges Bank region. On the Bank in...
In this thesis we review the methods for computation of cosmological correlations in the early universe known as the in-in formalism which are then applied to the problem of magnetogenesis from inflation. For this computation, a power-law single...
Ocean circulation -- Georges Bank -- Mathematical models. ; Submarine topography -- Georges Bank.
A two-dimensional continuously-stratified model is derived for the study of instability properties of oceanic density fronts in the presence of sloping bottom topography. While the model retains several traditional assumptions, such as uniformity...
Multisensor data fusion. Sensor networks. Plumes (Fluid dynamics). Automatic tracking. Signal processing -- Digital techniques -- Mathematics.
The work in this thesis deals with a novel approach for detecting and tracking chemical plumes in distributed sensor networks. The ultimate objective is solving the inverse location problem: given unknown sources released at unknown times, the...
Cosmic acceleration could be an effect of a ""dark energy"" fluid pervading the Universe. It could also be an indication that general relativity is not the correct theory of gravity at cosmological length scales. Unfortunately, observations of the...
Despite great progress in object recognition techniques, there is a mismatch between traditional approaches and the characteristics of real world vision tasks. We highlight in particular, three closely related areas of mismatch: i) recognition...
We expect wireless body-area networks of pervasive wearable devices will enable in situ health monitoring, personal assistance, entertainment personalization, and home automation. As these devices become ubiquitous, we also expect them to...
Investigations into alternative breast cancer (BC) imaging techniques have become increasingly popular based on the limitations of traditional imaging modalities: X-ray mammography uses ionizing radiation, has limited intrinsic contrast and is...