6,336 research outputs found

    Apollo experience report: The AN/ARD-17 direction finding system

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    This report contains a statement of the operational philosophy and requirements leading to the development of the AN/ARD-17 direction-finding system. The technical problems encountered and the solutions devised in the AN/ARD-17 development are discussed. An evaluation of the system under actual operational conditions is included

    Assessing Human Error Against a Benchmark of Perfection

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    An increasing number of domains are providing us with detailed trace data on human decisions in settings where we can evaluate the quality of these decisions via an algorithm. Motivated by this development, an emerging line of work has begun to consider whether we can characterize and predict the kinds of decisions where people are likely to make errors. To investigate what a general framework for human error prediction might look like, we focus on a model system with a rich history in the behavioral sciences: the decisions made by chess players as they select moves in a game. We carry out our analysis at a large scale, employing datasets with several million recorded games, and using chess tablebases to acquire a form of ground truth for a subset of chess positions that have been completely solved by computers but remain challenging even for the best players in the world. We organize our analysis around three categories of features that we argue are present in most settings where the analysis of human error is applicable: the skill of the decision-maker, the time available to make the decision, and the inherent difficulty of the decision. We identify rich structure in all three of these categories of features, and find strong evidence that in our domain, features describing the inherent difficulty of an instance are significantly more powerful than features based on skill or time.Comment: KDD 2016; 10 page

    Conical scan impact study. Volume 2: Small local user data processing facility

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    The impact of a conical scan versus a linear scan multispectral scanner (MSS) instrument on a small local-user data processing facility was studied. User data requirements were examined to determine the unique system rquirements for a low cost ground system (LCGS) compatible with the Earth Observatory Satellite (EOS) system. Candidate concepts were defined for the LCGS and preliminary designs were developed for selected concepts. The impact of a conical scan MSS versus a linear scan MSS was evaluated for the selected concepts. It was concluded that there are valid user requirements for the LCGS and, as a result of these requirements, the impact of the conical scanner is minimal, although some new hardware development for the LCGS is necessary to handle conical scan data

    InSb charge coupled infrared imaging device: The 20 element linear imager

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    The design and fabrication of the 8585 InSb charge coupled infrared imaging device (CCIRID) chip are reported. The InSb material characteristics are described along with mask and process modifications. Test results for the 2- and 20-element CCIRID's are discussed, including gate oxide characteristics, charge transfer efficiency, optical mode of operation, and development of the surface potential diagram

    Adaptive constraints for feature tracking

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    In this paper extensions to an existing tracking algorithm are described. These extensions implement adaptive tracking constraints in the form of regional upper-bound displacements and an adaptive track smoothness constraint. Together, these constraints make the tracking algorithm more flexible than the original algorithm (which used fixed tracking parameters) and provide greater confidence in the tracking results. The result of applying the new algorithm to high-resolution ECMWF reanalysis data is shown as an example of its effectiveness

    Chemical Equilibrium Abundances in Brown Dwarf and Extrasolar Giant Planet Atmospheres

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    We calculate detailed chemical abundance profiles for a variety of brown dwarf and extrasolar giant planet atmosphere models, focusing in particular on Gliese 229B, and derive the systematics of the changes in the dominant reservoirs of the major elements with altitude and temperature. We assume an Anders and Grevesse (1989) solar composition of 27 chemical elements and track 330 gas--phase species, including the monatomic forms of the elements, as well as about 120 condensates. We address the issue of the formation and composition of clouds in the cool atmospheres of substellar objects and explore the rain out and depletion of refractories. We conclude that the opacity of clouds of low--temperature (≤\le900 K), small--radius condensibles (specific chlorides and sulfides), may be responsible for the steep spectrum of Gliese 229B observed in the near infrared below 1 \mic. Furthermore, we assemble a temperature sequence of chemical transitions in substellar atmospheres that may be used to anchor and define a sequence of spectral types for substellar objects with Teff_{eff}s from ∼\sim2200 K to ∼\sim100 K.Comment: 57 pages total, LaTeX, 14 figures, 5 tables, also available in uuencoded, gzipped, and tarred form via anonymous ftp at www.astrophysics.arizona.edu (cd to pub/burrows/chem), submitted to Ap.

    Paper EL-89-10 v. 1: Fort Monmouth, New Jersey, Water Distribution Systems

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    This report was prepared by the Environmental Laboratory (EL), US Army Engineer Waterways Experiment Station (WES), in partial fulfillment of Reimbursable Order No. 88-G4-07 from the Fort Monmouth Directorate of Engineering and Housing (DLH), Fort Monmouth, NJ. The report was prepared by Mr. Wayne W. Sharp, Mr. Donald V. Chase, and Dr. Paul R. Schroeder of the Water Resources Engineering Group (WREG), Environmental Engineering Division (EED), EL. The work was accomplished under the direct supervision of Dr. John J. Ingram. Chief, WREG, and Dr. Raymond L. Montgomery, Chif, EED: qnA -Asr the general supervision of Dr. John Keeley, Assistant Chief, EL, and Dr. John Harrison, Chief, EL. The authors gratefully acknowledge the help of Mr. Terry Taylor in the collection of field data as well as date supplied by Mr. Mike Maier, Mr. Jim Ott and Ms. Lori Kam of the Fort Monmouth DEH. Commander and Director of WES was COL Larry B. Fulton, EN. Dr. Robert W. Whalin was Technical Director

    Vacuum-UV negative photoion spectroscopy of CF3Cl, CF3Br and CF3I

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    Using synchrotron radiation negative ions have been detected by mass spectrometry following vacuum-UV photoexcitation of trifluorochloromethane (CF3_3Cl), trifluorobromomethane (CF3_3Br) and trifluoroiodomethane (CF3_3I). The anions F−^-, X−^-, F2−_2^-, FX−^-, CF−^-, CF2−_2^- and CF3−_3^- were observed from all three molecules, where X = Cl, Br or I, and their ion yields recorded in the range 8-35 eV. With the exception of Br−^- and I−^-, the anions observed show a linear dependence of signal with pressure, showing that they arise from unimolecular ion-pair dissociation. Dissociative electron attachment, following photoionization of CF3_3Br and CF3_3I as the source of low-energy electrons, is shown to dominate the observed Br−^- and I−^- signals, respectively. Cross sections for ion-pair formation are put on to an absolute scale by calibrating the signal strengths with those of F−^- from both SF6_6 and CF4_4. These anion cross sections are normalized to vacuum-UV absorption cross sections, where available, and the resulting quantum yields are reported. Anion appearance energies are used to calculate upper limits to 298 K bond dissociation energies for D0D^0(CF3_3-X) which are consistent with literature values. We report new data for D0D^0(CF2_2I−^--F) ≤ 2.7 ± 0.2 eV and ΔfH2980\Delta_fH^0_{298} (CF2_2I+^+) ≤ (598 ± 22) kJ mol−1^{-1}. No ion-pair formation is observed below the ionization energy of the parent molecule for CF3_3Cl and CF3_3Br, and only weak signals (in both I−^- and F−^-) are detected for CF3_3I. These observations suggest neutral photodissociation is the dominant exit channel to Rydberg state photoexcitation at these lower energies
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