Attitude control system

An attitude control system is described in which angular rate signals are generated by rate gyros mounted closely adjacent to gimbaled engines at the rear of a vehicle. Error signals representative of a commanded change in vehicle angle or attitude are obtained from a precision inertial platform located in the nose region of the vehicle. The rate gyro derived signals dominate at high frequencies where dynamic effects become significant, and platform signals dominate at low frequencies where precision signals are required for a steady vehicle attitude. The blended signals are applied in a conventional manner to control the gimbaling of vehicle engines about control axes

A performance comparison of fullband and different subband adaptive equalisers

We present two different fractionally spaced (FS) equalisers based on subband methods, with the aim of reducing the computational complexity and increasing the convergence rate of a standard fullband FS equaliser. This is achieved by operating in decimated subbands; at a considerably lower update rate and by exploiting the prewhitening effect that a filter bank has on the considerable spectral dynamics of a signal received through a severely distorting channel. The two presented subband structures differ in their level of realising the feedforward and feedback part of the equaliser in the subband domain, with distinct impacts on the updating. Simulation results pinpoint the faster convergence at lower cost for the proposed subband equalisers

Non-Ergodic Behaviour of the k-Body Embedded Gaussian Random Ensembles for Bosons

We investigate the shape of the spectrum and the spectral fluctuations of the $k$-body Embedded Gaussian Ensemble for Bosons in the dense limit, where the number of Bosons $m \to \infty$ while both $k$, the rank of the interaction, and $l$, the number of single-particle states, are kept fixed. We show that the relative fluctuations of the low spectral moments do not vanish in this limit, proving that the ensemble is non-ergodic. Numerical simulations yield spectra which display a strong tendency towards picket-fence type. The wave functions also deviate from canonical random-matrix behaviourComment: 7 pages, 5 figures, uses epl.cls (included

Patterns, Tables & Equations: Using Lesson Study to Improve Algebraic Connections

Middle school mathematics teachers are faced with the challenge of laying the foundation for algebra, geometry and statistics while extending student understanding of number sense and operations. Based upon feedback from the textbook analysis completed for the Third International Study of Science and Mathematics, three-year middle school math programs were developed to engage students in a standards-based, problem solving curricula (Huetinck & Mushnin, 2000). One of these standards-based programs is the Com1ected Mathematics Project (CMP) which has been adopted by Greece Central School District. In order to utilize this program to its maximum potential, a method of professional development known as Japanese lesson study was used by my colleague and me to develop and improve our students\u27 understanding of algebraic ideas at the 7th grade level

BIOGEOCHEMICAL RESPONSE TO VEGETATION AND HYDROLOGIC CHANGE IN AN ALASKAN BOREAL FEN ECOSYSTEM

Boreal peatlands store approximately one third of the earth’s terrestrial carbon, locked away in currently waterlogged and frozen conditions. Peatlands of boreal and arctic ecosystems are affected increasingly by shifting hydrology caused by climate change. The consequences of these relatively rapid ecosystem changes on carbon cycling between the landscape and the atmosphere could provide an amplifying feedback to climate warming. Alternatively, the advancement of terrestrial vegetation into once waterlogged soils could uptake carbon as a sink. Previous work suggests that fens will become an increasingly dominant landscape feature in the boreal. However, studies investigating fens, their response to hydrologic and vegetative change, and their carbon cycling dynamics are relatively few compared with other peatland types. This research investigates the biological and geochemical controls over carbon dioxide and methane cycling in a central Alaskan rich fen. The research concentrates on how these processes react to changes in water table and vegetation composition. The objectives of this body of research were to 1) Gain insights on how water table change affects carbon dioxide and methane transformation in a boreal rich fen from the pore water to the atmosphere; 2) Assess the mechanistic controls of specific boreal rich fen plant functional groups on carbon cycling; and 3) Profile the microbial community of a boreal rich fen and report on its response to water table change and specific plant functional groups. Although the oxidation of methane is prevalent in the studied rich fen, a raised water table and associated root exudates from greater sedge abundance fuels greater methane production than oxidation, for a net effect of greater methane production. However, the net methane that is released from the fen site is likely diminished compared with expected emissions due to the oxidizing nature of sedge, grass, and horsetail rhizospheres. Methanogens may also be in competition with other microorganisms for metabolic resources in this fen, which is recharged by the cyclic rewetting characteristic of these ecosystems. Overall, fens as a peatland type appear to have a resilience buffer in their carbon cycling response to hydrologic change more so than other peatland types

Using Google Analytics, Voyant and Other Tools to Better Understand Use of Manuscript Collections at L. Tom Perry Special Collections

[Excerpt] Developing strategies for making data-driven, objective decisions for digitization and value-added processing. based on patron usage has been an important effort in the L. Tom Perry Special Collections (hereafter Perry Special Collections). In a previous study, the authors looked at how creating a matrix using both Web analytics and in-house use statistics could provide a solid basis for making decisions about which collections to digitize as well as which collections merited deeper description. Along with providing this basis for decision making, the study also revealed some intriguing insights into how our collections were being used and raised some important questions about the impact of description on both digital and physical usage. We have continued analyzing the data from our first study and that data forms the basis of the current study. It is helpful to review the major outcomes of our previous study before looking at what we have learned in this deeper analysis. In the first study, we utilized three sources of statistical data to compare two distinct data points (in-house use and online finding aid use) and determine if there were any patterns or other information that would help curators in the department make better decisions about the items or collections selected for digitization or value-added processing. To obtain our data points, we combined two data sources related to the in-person use of manuscript collections in the Perry Special Collections reading room and one related to the use of finding aids for manuscript collections made available online through the department’s Finding Aid database ( http://findingaid.lib.byu.edu/). We mapped the resulting data points into a four quadrant graph (see figure 1)

Energy efficiency of mmWave massive MIMO precoding with low-resolution DACs

With the congestion of the sub-6 GHz spectrum, the interest in massive multiple-input multiple-output (MIMO) systems operating on millimeter wave spectrum grows. In order to reduce the power consumption of such massive MIMO systems, hybrid analog/digital transceivers and application of low-resolution digital-to-analog/analog-to-digital converters have been recently proposed. In this work, we investigate the energy efficiency of quantized hybrid transmitters equipped with a fully/partially-connected phase-shifting network composed of active/passive phase-shifters and compare it to that of quantized digital precoders. We introduce a quantized single-user MIMO system model based on an additive quantization noise approximation considering realistic power consumption and loss models to evaluate the spectral and energy efficiencies of the transmit precoding methods. Simulation results show that partially-connected hybrid precoders can be more energy-efficient compared to digital precoders, while fully-connected hybrid precoders exhibit poor energy efficiency in general. Also, the topology of phase-shifting components offers an energy-spectral efficiency trade-off: active phase-shifters provide higher data rates, while passive phase-shifters maintain better energy efficiency.Comment: Published in IEEE Journal of Selected Topics in Signal Processin

Exploring root rot pathogens in wheat-pea rotations in Kansas

In 2018, over 277,000 bushels of wheat were produced on 7.7 million acres of land in Kansas alone. Based on the price of wheat by the end of 2018, this accounted for $1.44 million. This wheat is normally rotated with soybeans or fallow, but recent interest has arisen regarding the growth of peas in northern Kansas. As of 2019, there are both research and commercial growing operations underway. Many plant diseases have been especially prevalent during the summer because of the high rainfall and heat. In order to assess the severity of pea disease in Kansas, as well as explore potential interconnectivity between wheat and pea pathogens, a survey was conducted, and efforts were made to isolate and culture fungal pathogens of both wheat and pea