4,505 research outputs found

    Evaluating human performance modeling for system assessment: Promise and problems

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    The development and evaluation of computational human performance models is examined. An intention is to develop models which can be used to interact with system prototypes and simulations to perform system assessment. Currently LR is working on a set of models emulating cognitive, psychomotor, auditory, and visual activity for multiple operator positions of a command and control simulation system. These models, developed in conjunction with BBN Systems and Technologies, function within the simulation environment and allow for both unmanned system assessment and manned (human-in-loop) assessment of system interface and team interactions. These are relatively generic models with built-in flexibility which allows modification of some model parameters. These models have great potential for improving the efficiency and effectiveness of system design, test, and evaluation. However, the extent of the practical utility of these models is unclear. Initial verification efforts comparing model performance within the simulation to actual human operators on a similar, independent simulation have been performed and current efforts are directed at comparing human and model performance within the same simulation environment

    A Study of the Trypsinlike Protease of the Adult Stable Fly, Stomoxys Calcitrans (L.)

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    Author Institution: Department of Zoology and Entomology, The Ohio State University, Columbu

    A Fistful of Polemoniaceae: New Names and Combinations

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    New taxa, names, and combinations are provided for five genera in Polemoniaceae: Dayia, Giliastrum, Leptosiphon, Linanthus, and Loeselia. Combinations include the transfer to Dayia of two species formerly included in Ipomopsis and one in Bryantiella (Dayia glutinosa, D. havardii, and D. sonorae), as well as the return of Giliastrum stewartii to species rank. A new name is offered for Linanthus aureus when transferred into Leptosiphon: Leptosiphon chrysanthus and its subspecies, L. chrysanthus subsp. decorus. New combinations for infraspecific taxa are made available for Linanthus californicus (subspp. glandulosus and tomentosus) and L. pungens (subspp. hookeri, pulchriflorus, and hallii). New subspecies are described for Linanthus bigelovii (subsp. johnsonii), L. dichotomus (subsp. pattersonii), L. maculatus (subsp. emaculatus), L. watsonii (subspp. laccolithicus and dolomiticus), and Loeselia glandulosa (subsp. sonorae). Linanthus maricopensis is described as new. In addition, 10 lectotypes are designated, associated with Dayia, Leptosiphon, and Linanthus

    Hypercube technology

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    The JPL designed MARKIII hypercube supercomputer has been in application service since June 1988 and has had successful application to a broad problem set including electromagnetic scattering, discrete event simulation, plasma transport, matrix algorithms, neural network simulation, image processing, and graphics. Currently, problems that are not homogeneous are being attempted, and, through this involvement with real world applications, the software is evolving to handle the heterogeneous class problems efficiently

    Diverter AI based decision aid, phases 1 and 2

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    It was determined that a system to incorporate artificial intelligence (AI) into airborne flight management computers is feasible. The AI functions that would be most useful to the pilot are to perform situational assessment, evaluate outside influences on the contemplated rerouting, perform flight planning/replanning, and perform maneuver planning. A study of the software architecture and software tools capable of demonstrating Diverter was also made. A skeletal planner known as the Knowledge Acquisition Development Tool (KADET), which is a combination script-based and rule-based system, was used to implement the system. A prototype system was developed which demonstrates advanced in-flight planning/replanning capabilities

    Nodulation, Nitrogen Fixation, and Organ Dry Weight of Soybean Infested with Southern Corn Rootworm (Coleoptera: Chrysomelidae) Larvae

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    Nitrogen fixation, nodulation, and organ dry weights of soybean infested with the larvae of the southern corn rootworm, Diabrotica undecimpunctata howardi Barber, were estimated under controlled conditions. Larval southern com rootworm reduced the nitrogen-fixing activity of mid-vegetative and early reproductive soybean, Glycine max Merrill. Soybean of both stages responded to the infestation and subsequent injury by increasing nodulation and organ dry weights of below-ground tissues relative to above-ground tissues. Infestation increased the dry weight of small nodules on vegetative plants and caused a 78.6% increase in the total number of nodules on R5 plants. Leaf area as well as leaf and stem dry weight was reduced in vegetative plants by infestatio

    Maternal Influenza Infection Causes Marked Behavioral and Pharmacological Changes in the Offspring

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    Maternal viral infection is known to increase the risk for schizophrenia and autism in the offspring. Using this observation in an animal model, we find that respiratory infection of pregnant mice (both BALB/c and C57BL/6 strains) with the human influenza virus yields offspring that display highly abnormal behavioral responses as adults. As in schizophrenia and autism, these offspring display deficits in prepulse inhibition (PPI) in the acoustic startle response. Compared with control mice, the infected mice also display striking responses to the acute administration of antipsychotic (clozapine and chlorpromazine) and psychomimetic (ketamine) drugs. Moreover, these mice are deficient in exploratory behavior in both open-field and novel-object tests, and they are deficient in social interaction. At least some of these behavioral changes likely are attributable to the maternal immune response itself. That is, maternal injection of the synthetic double-stranded RNA polyinosinic-polycytidylic acid causes a PPI deficit in the offspring in the absence of virus. Therefore, maternal viral infection has a profound effect on the behavior of adult offspring, probably via an effect of the maternal immune response on the fetus

    High Thrust-to-Power Annular Engine Technology

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    Gridded ion engines have the highest efficiency and total impulse of any mature electric propulsion technology, and have been successfully implemented for primary propulsion in both geocentric and heliocentric environments with excellent ground/in-space correlation of performance. However, they have not been optimized to maximize thrust-to-power, an important parameter for Earth orbit transfer applications. This publication discusses technology development work intended to maximize this parameter. These activities include investigating the capabilities of a non-conventional design approach, the annular engine, which has the potential of exceeding the thrust-to-power of other EP technologies. This publication discusses the status of this work, including the fabrication and initial tests of a large-area annular engine. This work is being conducted in collaboration among NASA Glenn Research Center, The Aerospace Corporation, and the University of Michigan

    Exploring Halo Substructure with Giant Stars IV: The Extended Structure of the Ursa Minor Dwarf Spheroidal

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    We present a large area photometric survey of the Ursa Minor dSph. We identify UMi giant star candidates extending to ~3 deg from the center of the dSph. Comparison to previous catalogues of stars within the tidal radius of UMi suggests that our photometric luminosity classification is 100% accurate. Over a large fraction of the survey area, blue horizontal branch stars associated with UMi can also be identified. The spatial distribution of both the UMi giant stars and the BHB stars are remarkably similar, and a large fraction of both samples of stars are found outside the tidal radius of UMi. An isodensity contour map of the stars within the tidal radius of UMi reveals two morphological peculiarities: (1) The highest density of dSph stars is offset from the center of symmetry of the outer isodensity contours. (2) The overall shape of the outer contours appear S-shaped. We find that previously determined King profiles with ~50' tidal radii do not fit well the distribution of our UMi stars. A King profile with a larger tidal radius produces a reasonable fit, however a power law with index -3 provides a better fit for radii > 20'. The existence of UMi stars at large distances from the core of the galaxy, the peculiar morphology of the dSph within its tidal radius, and the shape of its surface density profile all suggest that UMi is evolving significantly due to the tidal influence of the Milky Way. However, the photometric data on UMi stars alone does not allow us to determine if the candidate extratidal stars are now unbound or if they remain bound to the dSph within an extended dark matter halo. (Abridged)Comment: accepted by AJ, 32 pages, 15 figures, emulateapj5 styl
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