Attitude determination of GPS satellite vehicles

There is an increasing demand for navigation systems that has led to rapid development of Global Positioning System (GPS) across industries. Apart from position and speed, precise attitude measurements are needed for many GPS applications. This thesis presents techniques for attitude determination of satellite vehicles in both real-time and stand-alone positioning applications. The GPS system used is a differential GPS system that estimates the body frame baselines using at least four receivers. The attitude information is obtained using these baselines and projecting them onto a local level frame. Integer ambiguity is a major constraint in attitude determination. Least Squares Ambiguity Deco-relation method is implemented to fix the ambiguities prior to baseline estimation. Estimation techniques such as Least Squares and Kalman Filter are implemented for deriving baseline components. Finally, this system will compute body frame coordinates and attitude components in reference to the desired coordinate frames.Engineering Technology, Department o

The Librarian & the Big Data: Bridging the Gap

Arcot Rajasekar, PhD, is Professor in the School of Information and Science, Chief Scientist for the Renaissance Computing Institute, and Co-Director of the Data Intensive Cyber Environments Center, all at the University of North Carolina at Chapel Hill. He spoke on how the library and information science community can meet the challenges of the scientific data explosion

The Traumatic State of Psychology: An Investigation of the Challenges Psychologists Face When Aiming to Help Trauma Survivors in Post-Apartheid South Africa

This project will sought to investigate the difficult role that psychologists play in post-apartheid South Africa, particularly when they are trying to create meaningful change for trauma survivors from the apartheid era. Many survivors found the results of the Truth and Reconciliation Commission (TRC) unsatisfactory, and thus still suffer from trauma (Kagee, Naidoo, & Van Wyk, 2013). There is a clear need in the present society of South Africa for a system which helps these trauma survivors find reconciliation and make peace with the atrocities of the past. Part of this system is the counseling psychologists that focus on the trauma that these survivors are still afflicted with. However, for a myriad of reasons, this task is an exceedingly difficult one for psychologists. In order to understand these challenges, the researcher will interview a variety of psychologists to learn what problems they face in their work as well as how they work to overcome these challenges and still provide effective care for their patients. This study will illuminate the difficulties that mental health professionals handle on a daily basis, and as a corollary will show how it is hard for mental health patients to fully move on from the apartheid era. This project is relevant because psychology is still in a transitional state in South Africa (Cooper & Nicholas, 2012a) and has a paramount role in shaping the future society in South Africa. Moreover, many people in South Africa suffer from lingering effects of the apartheid era, and their stories and situations are crucial to present-day South African society. This project can be of use to the South African people because it is hoped that a synthesis of the interviews will reveal commonalities and differences among counseling psychologists that can be of use to experts in this field. The results from the interviews showed that the majority of challenges counselors face come from the legacy of apartheid. In addition to the legacy of apartheid, the Western focus of psychology in South Africa also poses many challenges. A third major challenge is how to handle continuous traumatic stress because of how complicated it can be. Counselors have found many interesting solutions to these challenges including client-driven therapy, group therapy, community-oriented psychology, advocating beyond just counseling, and looking to evidence-based research

ISSUES RELATED TO THE NUMERICAL IMPLEMENTATION OF A SPARSE METHOD FOR THE SOLUTION OF VOLUME INTEGRAL EQUATIONS AT LOW FREQUENCIES

Computational electromagnetic modeling involves generating system matrices by discretizing integral equations and solving the resulting system of linear equations. Many methods of solving the system of linear equations exist and one such method is the factorization of the matrix using the so called local-global solution (LOGOS) modes. Computer codes to perform the discretization of the integral equations, filling of the matrix, and the subsequent LOGOS factorization have previously been developed by others. However, these codes are limited to complex double precision arithmetic only. This thesis extends and expands the existing computer by creating a more general implementation that is able to analyze a problem not only in complex double precision but also in real double precision and both complex and real single precision. The existing code is expanded using templates in Fortran 90 and the resulting generic code is used test the performance of the LOGOS (both OL- and NL-LOGOS) factorization on matrices generated by discretization of the volume integral equation. As part of this effort, we demonstrate for the first time that the LOGOS factorization provides an O(N log N) complexity solution to the volume integral equation formulation of low-frequency electromagnetic problems

CARDIO-RESPIRATORY INFLUENCE ON DYNAMIC CEREBRAL AUTOREGULATION DURING HEAD UP TILT MEDIATED PRESYNCOPE

Altered cerebral hemodynamics contributes to mechanisms of unexplained syncope. Wecompared dynamic interaction between respiration and cerebral autoregulation in two groups ofsubjects from 28 healthy adults. Based on development of tilt-induced presyncope, subjects wereclassified as Non-Presyncopals (n=23) and Presyncopals (n=5). Airflow, CO2, Doppler cerebralblood flow velocity (CBF), ECG and blood pressure (BP) were recorded. To determine whetherinfluences of mean BP (MBP) and systolic BP (SBP) on CBF were altered in Presyncopals, thecoherencies and transfer functions between these variables and mean and peak CBF (CBFm andCBFp) were estimated. To determine influence of end-tidal CO2 (ETCO2) on CBF, relative CO2reactivity was calculated. The two primary findings were, during tilt in Presyncopals: (1) Inrespiratory frequency region, coherence between SBP and CBFp (p=0.02) and transfer functiongain between BP and CBFm was higher (MBP, p=0.01, and SBP, p=0.01) than in Non-Presyncopals. (2) In the last 3 minutes prior to presyncope, Presyncopals had a reduced relativeCO2 reactivity (p=0.005). Thus the relationship of CBF with systemic BP was more pronouncedor cerebral autoregulation was less effective preceding presyncope. This decreasedautoregulation, secondary to decreased ETCO2, may contribute in the cascade of events leadingto unexplained syncope

GENETIC ALGORITHM CONTROLLED COMMON SUBEXPRESSION ELIMINATION FOR SPILL-FREE REGISTER ALLOCATION

As code complexity increases, maxlive increases. This is especially true in the case of the Kentucky If-Then-Else architecture proposed for Nanocontrollers. To achieve low circuit complexity, computations are decomposed to bit-level operations, thus generating large blocks of code with complex dependence structures. Additionally, the Nanocontroller architecture allows for only a small number of single bit registers and no extra memory. The assumption of an infinite number of registers made during code generation becomes a huge problem during register allocation because the small number of registers and no additional memory. The large basic blocks mean that maxlive almost always exceeds the number of registers and the traditional methods of register allocation such as instruction re-ordering and register spill/reload cannot be applied trivially. This thesis deals with finding a solution to reduce maxlive for successful register allocation using Genetic Algorithms

Fortification of foods with nano-iron: Its uptake and potential toxicity: Current evidence, controversies, and research gaps

Iron fortification is a very popular practice in several countries, particularly in countries in which a large proportion of the population is suffering from iron deficiency, as in lower-middle-income countries. Food fortification with iron salts is a difficult operation, because most iron complexes (ferrous sulfate, ferrous chloride) are water soluble, which can cause undesirable alterations to the sensory properties of the food carriers. On the other hand, insoluble iron salts (eg, ferric pyrophosphate) do not have an unpleasant taste or color, but their bioavailability is low. These issues can be addressed with iron nanoparticles. The small particle size has been shown to have a significant impact on iron absorption. Iron nanoparticles with smaller particle sizes have more surface area, which improves their solubility in gastric juice and leads to better bioavailability. When compared with water-soluble iron complexes, nano-sized iron compounds generate negligible organoleptic alterations in food carriers. As a result, iron nanoparticles could be potentially used in food fortification to minimize iron-deficiency anemia. This review focuses on the absorption pathway and the toxicity of various forms of iron nanoparticles. In vitro cell studies and animal studies indicate that nano-sized iron particles can be taken up either by the Divalent Metal Transporter 1 pathway or the endocytic pathway. Nano-sized ferric phosphate and iron(III) oxo hydroxide show the most promising results, based on recent studies on fortification. To date, there are insufficient studies on the maximum intake level and potential adverse effects. Further extensive work is essential before introducing nano-iron compounds as food fortificants

Development of a Stress Corrosion Cracking test approach for multi-mode measurements

Experimentation to study stress corrosion cracking (SCC) often requires simulation of aggressive environments that include both tensile loading with simultaneous chemical exposure. This demands complex testing approaches that will benefit from multi-mode measurements to capture in-situ degradation. Multi-mode measurements aid in characterizing the nature of the reaction, quantifying the formation of corrosive products and in calculating the breakdown potential of the sample. This paper details a testing approach for the chemical aspect of SCC on aluminum samples where sample and experimental design facilitates in-situ imaging. In initial tests, 3.5 wt. % NaCl solution is applied to AA7075 for specific time frames which initiate the pitting process. The testing approach enables to produce optical microscope images of real-time reactions. Raman and microscopy measurements help capturing failure initiation mechanisms which eventually lead to crack propagation. Identification of specific Raman peaks reveals the nature of the products formed on the surface using the pre-exposure values as a baseline for the characterization. These results from multi-mode measurements can be compared to understand SCC processes with both qualitative and quantitative information. Knowledge gained can be used to design materials and processes to better withstand corrosive environments