Method and apparatus for spur-reduced digital sinusoid synthesis

A technique for reducing the spurious signal content in digital sinusoid synthesis is presented. Spur reduction is accomplished through dithering both amplitude and phase values prior to word-length reduction. The analytical approach developed for analog quantization is used to produce new bounds on spur performance in these dithered systems. Amplitude dithering allows output word-length reduction without introducing additional spurs. Effects of periodic dither similar to that produced by a pseudo-noise (PN) generator are analyzed. This phase dithering method provides a spur reduction of 6(M + 1) dB per phase bit when the dither consists of M uniform variates. While the spur reduction is at the expense of an increase in system noise, the noise power can be made white, making the power spectral density small. This technique permits the use of a smaller number of phase bits addressing sinusoid look-up tables, resulting in an exponential decrease in system complexity. Amplitude dithering allows the use of less complicated multipliers and narrower data paths in purely digital applications, as well as the use of coarse-resolution, highly-linear digital-to-analog converters (DAC's) to obtain spur performance limited by the DAC linearity rather than its resolution

Wayfinding and Navigation for People with Disabilities Using Social Navigation Networks

To achieve safe and independent mobility, people usually depend on published information, prior experience, the knowledge of others, and/or technology to navigate unfamiliar outdoor and indoor environments. Today, due to advances in various technologies, wayfinding and navigation systems and services are commonplace and are accessible on desktop, laptop, and mobile devices. However, despite their popularity and widespread use, current wayfinding and navigation solutions often fail to address the needs of people with disabilities (PWDs). We argue that these shortcomings are primarily due to the ubiquity of the compute-centric approach adopted in these systems and services, where they do not benefit from the experience-centric approach. We propose that following a hybrid approach of combining experience-centric and compute-centric methods will overcome the shortcomings of current wayfinding and navigation solutions for PWDs

Report of Meeting for the Purpose of Obtaining the Views of the Three Affiliated Tribes of the Fort Berthold Reservation on the Lieu Lands Offered by the Secretary of War, 1946

Notice of meeting in the Secretary\u27s conference room to obtain the views of the Three Affiliated Tribes of the Fort Berthold Reservation of the lieu lands offered by the Secretary of War. Provides a copy of the transcript for the meeting and the exhibits explained during the meeting. Includes: Section 6 Public Law 374, 79th Congress 2d session, memorandum to Secretary of the interior from the acting commissioner of Indian Affairs on subject of Transmitting correspondence to Secretary, Letter from Chairman George Gillette accepting invitation to have representatives of the Three Affiliated Tribes at a special hearing. Also includes: notice to all members of the Three Affiliated Tribes of the Fort Berthold Reservation listing a schedule of meetings to be held to discuss offer and inform tribe of schedule; list of attendees and comments for meeting in Lucky Mound District on December 5, 1946; list of attendees and comments in Red Butte District on December 5, 1946; List of attendees and comments in Charging Eagle District on December 6, 1946; List of attendees and comments in Independence District on December 7, 1946; List of attendees and comments in Nishu District on December 8, 1946; List of attendees and comments in Shell Creek District on December 9, 1946; Resolution announcing rejection to offer for the lieu lands offered to the Three Affiliated Tribes; and Exhibit 4 - formal rejection of offer, and Exhibit 5 - letter from J.A. Krug, Secretary of the Intererior) warranted a restudy of the lands. See also: Report of Second Meeting for the Purpose of Obtaining the Views of the Three Affiliated Tribes of the Fort Berthold Reservation on the Lieu Lands Offered by the Secretary of War, 1946https://commons.und.edu/langer-papers/1144/thumbnail.jp

Large constraint length high speed viterbi decoder based on a modular hierarchial decomposition of the deBruijn graph

A method of formulating and packaging decision-making elements into a long constraint length Viterbi decoder which involves formulating the decision-making processors as individual Viterbi butterfly processors that are interconnected in a deBruijn graph configuration. A fully distributed architecture, which achieves high decoding speeds, is made feasible by novel wiring and partitioning of the state diagram. This partitioning defines universal modules, which can be used to build any size decoder, such that a large number of wires is contained inside each module, and a small number of wires is needed to connect modules. The total system is modular and hierarchical, and it implements a large proportion of the required wiring internally within modules and may include some external wiring to fully complete the deBruijn graph. pg,14

Hydroacoustic Estimates of Fish Density Distributions in Cougar Reservoir, 2011

Day and night mobile hydroacoustic surveys were conducted once each month from April through December 2011 to quantify the horizontal and vertical distributions of fish throughout Cougar Reservoir, Lane County, Oregon

High contrast imaging at the LBT: the LEECH exoplanet imaging survey

In Spring 2013, the LEECH (LBTI Exozodi Exoplanet Common Hunt) survey began its $\sim$130-night campaign from the Large Binocular Telescope (LBT) atop Mt Graham, Arizona. This survey benefits from the many technological achievements of the LBT, including two 8.4-meter mirrors on a single fixed mount, dual adaptive secondary mirrors for high Strehl performance, and a cold beam combiner to dramatically reduce the telescope's overall background emissivity. LEECH neatly complements other high-contrast planet imaging efforts by observing stars at L' (3.8 $\mu$m), as opposed to the shorter wavelength near-infrared bands (1-2.4 $\mu$m) of other surveys. This portion of the spectrum offers deep mass sensitivity, especially around nearby adolescent ($\sim$0.1-1 Gyr) stars. LEECH's contrast is competitive with other extreme adaptive optics systems, while providing an alternative survey strategy. Additionally, LEECH is characterizing known exoplanetary systems with observations from 3-5$\mu$m in preparation for JWST.Comment: 12 pages, 5 figures. Proceedings of the SPIE, 9148-2

Black hole accretion disks in the canonical low-hard state

Stellar-mass black holes in the low-hard state may hold clues to jet formation and basic accretion disk physics, but the nature of the accretion flow remains uncertain. A standard thin disk can extend close to the innermost stable circular orbit, but the inner disk may evaporate when the mass accretion rate is reduced. Blackbody-like continuum emission and dynamically-broadened iron emission lines provide independent means of probing the radial extent of the inner disk. Here, we present an X-ray study of eight black holes in the low-hard state. A thermal disk continuum with a colour temperature consistent with $L \propto T^{4}$ is clearly detected in all eight sources, down to $\approx5\times10^{-4}L_{Edd}$. In six sources, disk models exclude a truncation radius larger than 10rg. Iron-ka fluorescence line emission is observed in half of the sample, down to luminosities of $\approx1.5\times10^{-3}L_{Edd}$. Detailed fits to the line profiles exclude a truncated disk in each case. If strong evidence of truncation is defined as (1) a non-detection of a broad iron line, {\it and} (2) an inner disk temperature much cooler than expected from the ${\rm L} \propto {\rm T}^{4}$ relation, none of the spectra in this sample offer strong evidence of disk truncation. This suggests that the inner disk may evaporate at or below $\approx1.5\times10^{-3}L_{Edd}$.Comment: Accepted for publication in MNRAS, 20 pages, 18 figure

Understanding and measuring child welfare outcomes

The new Children\u27s and Family Services Reviews (CFSR) process focuses on the effectiveness of services to children and families by measuring client outcomes. This article reviews the research literature related to child welfare outcomes in order to provide a context for federal accountability efforts. It also summarizes the 2001 federal mandate to hold states accountable for child welfare outcomes and describes California\u27s response to this mandate. Implications of the outcomes literature review and measurement problems in the CFSR process suggest CSFR measures do not always capture meaningful outcomes. Recommendations for change are made

Soil nitrogen concentration mediates the relationship between leguminous trees and neighbor diversity in tropical forests

Legumes provide an essential service to ecosystems by capturing nitrogen from the atmosphere and delivering it to the soil, where it may then be available to other plants. However, this facilitation by legumes has not been widely studied in global tropical forests. Demographic data from 11 large forest plots (16–60 ha) ranging from 5.25° S to 29.25° N latitude show that within forests, leguminous trees have a larger effect on neighbor diversity than non-legumes. Where soil nitrogen is high, most legume species have higher neighbor diversity than non-legumes. Where soil nitrogen is low, most legumes have lower neighbor diversity than non-legumes. No facilitation effect on neighbor basal area was observed in either high or low soil N conditions. The legume–soil nitrogen positive feedback that promotes tree diversity has both theoretical implications for understanding species coexistence in diverse forests, and practical implications for the utilization of legumes in forest restoration