78 research outputs found

    Internet Enabled Remote Driving of a Combat Hybrid Electric Power System for Duty Cycle Measurement

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    This paper describes a human-in-the-loop motion-based simulator interfaced to hybrid-electric power system hardware, both of which were used to measure the duty cycle of a combat vehicle in a virtual simulation environment. The project discussed is a greatly expanded follow-on to the experiment published in [1,7]. This paper is written in the context of [1,7] and therefore highlights the enhancements. The most prominent of these enhancements is the integration (in real-time) of the Power & Energy System Integration Lab (P&E SIL) with a motion base simulator by means of a “long haul” connection over the Internet (a geographical distance of 2,450 miles). The P&E SIL is, therefore, able to respond to commands issued by the vehicle’s driver and gunner and, in real-time, affect the simulated vehicle’s performance. By thus incorporating hardware into a human-in-the-loop experiment, TARDEC engineers were able to evaluate the actual power system as it responds to actual human behavior. After introducing the project, the paper describes the simulation environment which was assembled to run the experiment. It emphasizes the design of the experiment as well as the approach, challenges and issues involved in creating a real-time link between the motion-base simulator and the P&E SIL. It presents the test results and briefly discusses on-going and future work

    Identifying Nearby, Young, Late-type Stars by Means of Their Circumstellar Disks

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    It has recently been shown that a significant fraction of late-type members of nearby, very young associations (age <10 Myr) display excess emission at mid-IR wavelengths indicative of dusty circumstellar disks. We demonstrate that the detection of mid-IR excess emission can be utilized to identify new nearby, young, late-type stars including two definite new members ("TWA 33" and "TWA 34") of the TW Hydrae Association. Both new TWA members display mid-IR excess emission in the Wide-field Infrared Survey Explorer (WISE) catalog and they show proper motion and youthful spectroscopic characteristics -- namely H\alpha emission, strong lithium absorption, and low surface gravity features consistent with known TWA members. We also detect mid-IR excess -- the first unambiguous evidence of a dusty circumstellar disk -- around a previously identified UV-bright, young, accreting star (2M1337) that is a likely member of the Lower-Centaurus Crux region of the Scorpius Centaurus Complex.Comment: ApJ, Accepte

    The 6dF galaxy survey: Fundamental Plane data

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    We report the 6dFGS Fundamental Plane (6dFGSv) catalogue that is used to estimate distances and peculiar velocities for nearly 9000 early-type galaxies in the local (z < 0.055) universe. Velocity dispersions are derived by cross-correlation from 6dF V

    Soil Moisture Retrieval with Airborne PALS Instrument over Agricultural Areas in SMAPVEX16

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    NASA's SMAP (Soil Moisture Active Passive) calibration and validation program revealed that the soil moisture products are experiencing difficulties in meeting the mission requirements in certain agricultural areas. Therefore, the mission organized airborne field experiments at two core validation sites to investigate these anomalies. The SMAP Validation Experiment 2016 included airborne observations with the PALS (Passive Active L-band Sensor) instrument and intensive ground sampling. The goal of the PALS measurements are to investigate the soil moisture retrieval algorithm formulation and parameterization under the varying (spatially and temporally) conditions of the agricultural domains and to obtain high resolution soil moisture maps within the SMAP pixels. In this paper the soil moisture retrieval using the PALS brightness temperature observations in SMAPVEX16 is presented

    The M33 Globular Cluster System with PAndAS Data: The Last Outer Halo Cluster?

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    We use CFHT/MegaCam data to search for outer halo star clusters in M33 as part of the Pan-Andromeda Archaeological Survey (PAndAS). This work extends previous studies out to a projected radius of 50 kpc and covers over 40 square degrees. We find only one new unambiguous star cluster in addition to the five previously known in the M33 outer halo (10 kpc <= r <= 50 kpc). Although we identify 2440 cluster candidates of various degrees of confidence from our objective image search procedure, almost all of these are likely background contaminants, mostly faint unresolved galaxies. We measure the luminosity, color and structural parameters of the new cluster in addition to the five previously-known outer halo clusters. At a projected radius of 22 kpc, the new cluster is slightly smaller, fainter and redder than all but one of the other outer halo clusters, and has g' ~ 19.9, (g'-i') ~ 0.6, concentration parameter c ~ 1.0, a core radius r_c ~ 3.5 pc, and a half-light radius r_h ~ 5.5 pc. For M33 to have so few outer halo clusters compared to M31 suggests either tidal stripping of M33's outer halo clusters by M31, or a very different, much calmer accretion history of M33.Comment: 37 pages, 9 figures. Accepted by the Astrophysical Journa

    HI Selected Galaxies in the Sloan Digital Sky Survey I: Optical Data

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    We present the optical data for 195 HI-selected galaxies that fall within both the Sloan Digital Sky Survey (SDSS) and the Parkes Equatorial Survey (ES). The photometric quantities have been independently recomputed for our sample using a new photometric pipeline optimized for large galaxies, thus correcting for SDSS's limited reliability for automatic photometry of angularly large or low surface brightness (LSB) galaxies. We outline the magnitude of the uncertainty in the SDSS catalog-level photometry and derive a quantitative method for correcting the over-sky subtraction in the SDSS photometric pipeline. The main thrust of this paper is to present the ES/SDSS sample and discuss the methods behind the improved photometry, which will be used in future scientific analysis. We present the overall optical properties of the sample and briefly compare to a volume-limited, optically-selected sample. Compared to the optically-selected SDSS sample (in the similar volume), HI-selected galaxies are bluer and more luminous (fewer dwarf ellipticals and more star formation). However, compared to typical SDSS galaxy studies, which have their own selection effects, our sample is bluer, fainter and less massive.Comment: 14 pages, 8 Figures, accepted for publication in AJ. Complete tables will be available in the AJ electronic version and on the Vizier sit

    HI Selected Galaxies in the Sloan Digital Sky Survey II: The Colors of Gas-Rich Galaxies

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    We utilize color information for an HI-selected sample of 195 galaxies to explore the star formation histories and physical conditions that produce the observed colors. We show that the HI selection creates a significant offset towards bluer colors that can be explained by enhanced recent bursts of star formation. There is also no obvious color bimodality, because the HI selection restricts the sample to bluer, actively star forming systems, diminishing the importance of the red sequence. Rising star formation rates are still required to explain the colors of galaxies bluer than g-r < 0.3. We also demonstrate that the colors of the bluest galaxies in our sample are dominated by emission lines and that stellar population synthesis models alone (without emission lines) are not adequate for reproducing many of the galaxy colors. These emission lines produce large changes in the r-i colors but leave the g-r color largely unchanged. In addition, we find an increase in the dispersion of galaxy colors at low masses that may be the result of a change in the star formation process in low-mass galaxies.Comment: 12 pages, 16 figures, published in AJ (138, 796); replaced Figure 16 with higher resolution versio
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