4,663 research outputs found
Parallel-Interference-Cancellation-Assisted Decision-Directed Channel Estimation for OFDM Systems using Multiple Transmit Antennas
The number of transmit antennas that can be employed in the context of least-squares (LS) channel estimation contrived for orthogonal frequency division multiplexing (OFDM) systems employing multiple transmit antennas is limited by the ratio of the number of subcarriers and the number of significant channel impulse response (CIR)-related taps. In order to allow for more complex scenarios in terms of the number of transmit antennas and users supported, CIR-related tap prediction-filtering-based parallel interference cancellation (PIC)-assisted decision-directed channel estimation (DDCE) is investigated. New explicit expressions are derived for the estimatorâs mean-square error (MSE), and a new iterative procedure is devised for the offline optimization of the CIR-related tap predictor coefficients. These new expressions are capable of accounting for the estimatorâs novel recursive structure. In the context of our performance results, it is demonstrated, for example, that the estimator is capable of supporting L = 16 transmit antennas, when assuming K = 512 subcarriers and K0 = 64 significant CIR taps, while LS-optimized DDCE would be limited to employing L = 8 transmit antennas. Index TermsâDecision-directed channel estimation (DDCE), multiple transmit antennas, orthogonal frequency division multiplexing (OFDM), parallel interference cancellation (PIC)
A Possible Aoki Phase for Staggered Fermions
The phase diagram for staggered fermions is discussed in the context of the
staggered chiral Lagrangian, extending previous work on the subject. When the
discretization errors are significant, there may be an Aoki-like phase for
staggered fermions, where the remnant SO(4) taste symmetry is broken down to
SO(3). We solve explicitly for the mass spectrum in the 3-flavor degenerate
mass case and discuss qualitatively the 2+1-flavor case. From numerical results
we find that current simulations are outside the staggered Aoki phase. As for
near-future simulations with more improved versions of the staggered action, it
seems unlikely that these will be in the Aoki phase for any realistic value of
the quark mass, although the evidence is not conclusive.Comment: 27 pages, 8 figures, uses RevTe
Transmateriality: Toward an Energetics of Signal in Contemporary Mediatic Assemblages
This article focuses on signal as an aspect of modern technicity that precedesâor supersedesâcodification. Examining DIY drone videos found on YouTube and the video art of Nam June Paik, among other sources, the article explores how each tests the flow of signal and signal processing as forms of transmateriality and transduction. the author draws particularly on the work of Gilbert Simondon and Adrian Mackenzie
An Analysis of Citizen Science and its Effect on Marine Plastic Pollution
My Honors thesis is an analysis of pollution data to gain more insight about the growing problem of marine plastic pollution. I retrieved online datasets collected by the Clean Swell trash collection mobile application and then analyzed this data using the Python programming language. After my Python analysis, I used Tableau to create data visualizations. This paper analyzes the effect that citizen science has on plastic pollution. Syracuse Universityâs recycling and trash figures, provided by Syracuse Haulers, are also analyzed. The purpose of including Syracuse Universityâs data is to bring a local point of view to this project and possibly motivate readers to work towards a solution to marine plastic pollution
Development of the routine laboratory diagnosis of activated protein c resistance and its evaluation in a population of pregnant women
A Research Report submitted to the Faculty of Medicine, University of the Witwatersrand, in part fulfilment of the requirements for the degree of Master of Medicine in the branch of Haematology
Johannesburg, October 1997Venous thromboembolic disease is a common health problem. It contributes considerably to morbidity as well as to mortality. Thrombosis usually occurs due to an underlying risk factor which may be environmental or genetic in origin. The recently described activated Protein C (APC) resistance is the commonest cause of familial thrombophilia documented to date. The molecular lesion is a single point mutation in the factor V (FV) gene which abolishes a cleavage site whereby it is normally inactivated by APC. This defect, termed the FV Leiden mutation, is highly prevalent in normal Caucasian populations. Although it would appear to have arisen due to a founder effect, there is a paucity of data concerning non-Caucasian populations.IT201
Fire & Flood: How the Lessons of the Past can Apply to the Present to Build the Future
On August 29, 2005 the most destructive natural disaster to ever befall the United States made landfall initially near Buras, Louisiana and then ultimately near the mouth of the Pearl River. The associated storm surge caused New Orleans\u27 protective levee system to fail, inundating the City with brackish floodwaters for weeks on end. This was not the first time the City of New Orleans was crippled by disaster. In 1788 and 1794, the city suffered two major fires; the first burning 856 buildings and the second 212. These were significant losses in a city that had a building stock of approximately 1,000 buildings before the events. By recognizing the lessons learned in the earlier reconstructions of New Orleans, we can gain a better understanding of the rebuilding process that may forever effect the physical and cultural environments in the City of New Orleans
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