78 research outputs found

    The Washington University MultiMedia eXplorer

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    The Washington University MultiMedia eXplorer (MMX) is a complete, host-independent multimedia system capable of transmitting and receiving JPEG-compressed video, CD-quality audio, and high-resolution radiographic images over the Washington University broadband ATM network. If the host is equipped with an ATM interface card, normal network traffic is supported via T and Y connections. The MMX consists of an ATMizer and three multimedia subsystems. The ATMizer implements the host interface, the interface to the ATM network, and the interface to the three multimdeia channels. This paper describes the architecture of the MMX, the software used with the system, and the applications which have been developed to demonstrate the capability of broadband ATM networks for multimedia applications

    Production Quality Video Over Broadband Networks: A Description of the System and Two Interactive Applications

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    The Washington University MultiMedia eXplorer (MMX) is a complete, host-independent multimedia system capable of transmitting and receiving JPEG-compressed video, CD-quality audio, and high-resolution radiographic images over the Washington University broadband ATM network. If the host is equipped with an ATM interface card, normal network traffic can be supported via an ATM extension port on the MMX. The major components of the MMX are an ATMizer and three multimedia channels. The ATMizer implements the host interface, the interface to the ATM network, and hte interface to the three multimdeia channels. This paper describes the architecture of the MMX, the software used with the system, and two applications which have been developed to demonstrate the capability of broadband ATM networks for multimedia applications

    Estimating population size of largemouth bass and black crappie at The Nature Conservancy's Emiquon Preserve prior to reconnection to the Illinois River

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    Prior to completion of the water control structure at The Nature Conservancy’s Emiquon Nature Preserve (Emiquon), a mark-recapture study was conducted on largemouth bass Micropterus salmoides and black crappie Pomoxis nigromaculatus to estimate the populations of both species. Largemouth bass > 150 mm and black crappie > 100 mm were captured using pulsed-DC electrofishing, fyke nets, and tandem fyke nets and double tagged using T-bar style clear tags. Results of this study show very large populations of both species, with populations of largemouth bass estimated at 21,090 (17,110-27,484) and black crappie estimated at 205,042 (91,198-490,563). Information gained in this study will allow Nature Conservancy managers to make informed decisions on future management actions and allow for potential evaluation of those management actions on two major components of the recreational fishery at Emiquon.Ope

    Empirical performance assessment using soft-core processors on reconfigurable hardware

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    Simulation has been the de facto standard method for per-formance evaluation of newly proposed ideas in computer architecture for many years. While simulation allows for theoretically arbitrary delity (at least to the level of cycle accuracy) as well as the ability to monitor the architecture without perturbing the execution itself, it suers from low eective delity and long execution times. We (and others) have advocated the use of empirical ex-perimentation on recongurable hardware for computer ar-chitecture performance assessment. In this paper, we de-scribe an empirical performance assessment subsystem im-plemented in recongurable hardware and illustrate its use. Results are presented that demonstrate the need for the types of performance assessment that recongurable hard-ware can provide

    Mesospheric Bore Evolution and Instability Dynamics Observed in PMC Turbo Imaging and Rayleigh Lidar Profiling over Northeastern Canada on 13 July 2018

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    Two successive mesospheric bores were observed over northeastern Canada on 13 July 2018 in high-resolution imaging and Rayleigh lidar profiling of polar mesospheric clouds (PMCs) performed aboard the PMC Turbo long-duration balloon experiment. Four wide field-of-view cameras spanning an area of ~75x150 km at PMC altitudes captured the two evolutions occurring over ~2 hr and resolved bore and associated instability features as small as ~100 m. The Rayleigh lidar provided PMC backscatter profiling that revealed vertical displacements, evolving brightness distributions, evidence of instability character and depths, and insights into bore formation, ducting, and dissipation. Both bores exhibited variable structure along their phases, suggesting variable gravity wave (GW) source and bore propagation conditions. Both bores also exhibited small-scale instability dynamics at their leading and trailing edges. Those at the leading edges comprised apparent Kelvin-Helmholtz instabilities that were advected downward and rearward beneath the bore descending phases extending into an apparently intensified shear layer. Instabilities at the trailing edges exhibited alignments approximately orthogonal to the bore phases that resembled those seen to accompany GW breaking or intrusions arising in high-resolution modeling of GW instability dynamics. Collectively, PMC Turbo bore imaging and lidar profiling enabled enhanced definition of bore dynamics relative to what has been possible by previous ground-based observations, and a potential to guide new, three-dimensional modeling of bore dynamics. The observed bore evolutions suggest potentially important roles for bores in the deposition of energy and momentum transported into the mesosphere and to higher altitudes by high-frequency GWs achieving large amplitudes

    The long-term Illinois rivers fish population monitoring program 2014

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    This report presents a summary of those data collected during segment 26(2014-15) of the Long-term Illinois Rivers Fish Population Monitoring Program(LTEF), an annual survey executed by members of the Illinois Natural History Survey with funds administered by the U.S. Fish and Wildlife Service and the Illinois Department of Natural Resources. Sampling for the LTEF program was conducted on: six reaches of the Illinois River Waterway, six segments or pools of the Mississippi River, and navigable portions of the Iroquois and Kankakee Rives. In all segments of the LTEF program, all fish species collected were accurately identified, tallied, measured, and weighed. The catch rates of sportfish species were calculated as the number of individuals collected per hour (CPUEN± standard error). Structural indices [Proportional Size Distribution (PSD) and Relative Weight (Wr)] were also calculated for species of interest to regional managers. Catch rates and species richness varied greatly among all sampling locations and sampling periods. Emerald Shiners and Gizzard Shad comprised the majority of the individuals caught, and Silver Carp and Common Carp accounted for the greatest proportion of the biomass collected in most sampling areas of the survey. The analysis of CPUEN and PSD trends in sportfish populations sampled by the program may indicate inter-annual recruitment patterns in sportfish populations around the state. Both Shovelnose Sturgeon and Blue Catfish were the two species most commonly encountered in the gill net surveys.IDNR Division of Fisheries Project F-101-R, Segment 26unpublishednot peer reviewe

    Over 50 years of fish community monitoring in Illinois’ large rivers: The evolution of methods used by the Illinois Natural History Survey’s Long-term Survey and Assessment of Large-River Fishes in Illinois

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    Federal Aid in Sport Fish Restoration Act (F-101-R), administered by the U.S. Fish and Wildlife Service and Illinois Department of Natural Resourcesis peer reviewedOpe

    Gravity Wave Breaking and Vortex Ring Formation Observed by PMC Turbo

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    Polar mesospheric cloud (PMC) imaging and lidar profiling performed aboard the 5.9 day PMC Turbo balloon flight from Sweden to northern Canada in July 2018 revealed a wide variety of gravity wave (GW) and instability events occurring nearly continuously at approximately 82 km. We describe one event exhibiting GW breaking and associated vortex rings driven by apparent convective instability. Using PMC Turbo imaging with spatial and temporal resolution of 20 m and 2 s, respectively, we quantify the GW horizontal wavelength, propagation direction, and apparent phase speed. We identify vortex rings with diameters of 2‐5 km and horizontal spacing comparable to their size. Lidar data show GW vertical displacements of ±0.3 km. From the data, we find a GW intrinsic frequency and vertical wavelength of 0.009 ± 0.003 rad s‐1 and 9 ± 4 km, respectively. We show that these values are consistent with the predictions of numerical simulations of idealized GW breaking. We estimate the momentum deposition rate per unit mass during this event to be 0.04 ± 0.02 m s‐2 and show that this value is consistent with the observed GW. Comparison to simulation gives a mean energy dissipation rate for this event of 0.05‐0.4 W kg‐1, which is consistent with other reported in‐situ measurements at the Arctic summer mesopause

    Multi-Scale Kelvin-Helmholtz Instability Dynamics Observed by PMC Turbo on 12 July 2018: 1. Secondary Instabilities and Billow Interactions

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    The Polar Mesospheric Cloud (PMC) Turbulence experiment performed optical imaging and Rayleigh lidar PMC profiling during a 6-day flight in July 2018. A mosaic of seven imagers provided sensitivity to spatial scales from 20 m to 100 km at a 2-s cadence. Lidar backscatter measurements provided PMC brightness profiles and enabled definition of vertical displacements of larger-scale gravity waves (GWs) and smaller-scale instabilities of various types. These measurements captured an interval of strong, widespread Kelvin-Helmholtz instabilities (KHI) occurring over northeastern Canada on July 12, 2018 during a period of significant GW activity. This paper addresses the evolution of the KHI field and the characteristics and roles of secondary instabilities within the KHI. Results include the imaging of secondary KHI in the middle atmosphere and multiple examples of KHI tube and knot (T&K) dynamics where two or more KH billows interact. Such dynamics have been identified clearly only once in the atmosphere previously. Results reveal that KHI T&K arise earlier and evolve more quickly than secondary instabilities of uniform KH billows. A companion paper by Fritts et al. (2022), https://doi.org/10.1029/2021JD035834 reveals that they also induce significantly larger energy dissipation rates than secondary instabilities of individual KH billows. The expected widespread occurrence of KHI T&K events may have important implications for enhanced turbulence and mixing influencing atmospheric structure and variability
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