14,107 research outputs found

    Reactive control and reasoning assistance for scientific laboratory instruments

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    Scientific laboratory instruments that are involved in chemical or physical sample identification frequently require substantial human preparation, attention, and interactive control during their operation. Successful real-time analysis of incoming data that supports such interactive control requires: (1) a clear recognition of variance of the data from expected results; and (2) rapid diagnosis of possible alternative hypotheses which might explain the variance. Such analysis then aids in decisions about modifying the experiment protocol, as well as being a goal itself. This paper reports on a collaborative project at the NASA Ames Research Center between artificial intelligence researchers and planetary microbial ecologists. Our team is currently engaged in developing software that autonomously controls science laboratory instruments and that provides data analysis of the real-time data in support of dynamic refinement of the experiment control. the first two instruments to which this technology has been applied are a differential thermal analyzer (DTA) and a gas chromatograph (GC). coupled together, they form a new geochemicstry and microbial analysis tool that is capable of rapid identification of the organiz and mineralogical constituents in soils. The thermal decomposition of the minerals and organics, and the attendance release of evolved gases, provides data about the structural and molecular chemistry of the soil samples

    Verification, Validation, and Solution Quality in Computational Physics: CFD Methods Applied to Ice Sheet Physics

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    Procedures and methods for veri.cation of coding algebra and for validations of models and calculations used in the aerospace computational fluid dynamics (CFD) community would be ef.cacious if used by the glacier dynamics modeling community. This paper presents some of those methods, and how they might be applied to uncertainty management supporting code veri.cation and model validation for glacier dynamics. The similarities and differences between their use in CFD analysis and the proposed application of these methods to glacier modeling are discussed. After establishing sources of uncertainty and methods for code veri.cation, the paper looks at a representative sampling of veri.cation and validation efforts that are underway in the glacier modeling community, and establishes a context for these within an overall solution quality assessment. Finally, a vision of a new information architecture and interactive scienti.c interface is introduced and advocated

    Dynamics of Snow and Ice Masses, edited by Samuel C. Colbeck

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    Coherent Emission from Magnetars

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    It is proposed that magnetospheric currents above the surfaces of magnetars radiate coherent emission in analogy to pulsars. Scaling the magnetospheric parameters suggests that the coherent emission from magnetars would emerge in the infra-red or optical

    Optical Spectroscopy of K-selected Extremely Red Galaxies

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    We have obtained spectroscopic redshifts for 24 red galaxies from a sample with median Ks=18.7 and F814W - Ks > 4, using the Keck telescope. These EROshave high resolution morphologies from HST (Yan & Thompson 2003). Among the 24 redshifts, the majority (92%) are at 0.9<z<1.5 0.9 < z < 1.5. We derived the rest-frame J-band luminosity function at zmedian=1.14z_{median} =1.14. Our result suggests that the luminosity evolution between bright EROs at z∼1z\sim 1 and the present-day >>L∗^* massive galaxies is at most about 0.7 magnitude. Combining the morphologies and deep spectroscopy revealed the following properties: (1) 86% of the spectra have absorption features from old stars, suggesting that the dominant stellar populations seen in the rest-frame UV are old stars. 50% of the sources have pure absorption lines, while the remaining 50% have emission lines, indicating recent star formation. We conclude that the color criterion for EROs is very effective in selecting old stellar populations at z∼1z \sim 1, and a large fraction of these systems with prominent old stellar populations also have recent star formation. (2) The 12 emission line systems have the same number of disk and bulge galaxies as in the remaining 12 pure absorption line systems. We conclude that spectral classes do not have a simple, direct correspondence with morphological types. (3) Three EROs could be isolated, pure passively evolving early-type galaxies at z∼1z\sim 1. This implies that only a small fraction (10%--15%) of early-type galaxies are formed in a rapid burst of star formation at high redshifts and evolved passively since then. (Abridged).Comment: 27 pages, 8 figures. Accepted for publication in Astronomical Journal, issue March 200

    LISA Framework for Enhancing Gravitational Wave Signal Extraction Techniques

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    This paper describes the development of a Framework for benchmarking and comparing signal-extraction and noise-interference-removal methods that are applicable to interferometric Gravitational Wave detector systems. The primary use is towards comparing signal and noise extraction techniques at LISA frequencies from multiple (possibly confused) ,gravitational wave sources. The Framework includes extensive hybrid learning/classification algorithms, as well as post-processing regularization methods, and is based on a unique plug-and-play (component) architecture. Published methods for signal extraction and interference removal at LISA Frequencies are being encoded, as well as multiple source noise models, so that the stiffness of GW Sensitivity Space can be explored under each combination of methods. Furthermore, synthetic datasets and source models can be created and imported into the Framework, and specific degraded numerical experiments can be run to test the flexibility of the analysis methods. The Framework also supports use of full current LISA Testbeds, Synthetic data systems, and Simulators already in existence through plug-ins and wrappers, thus preserving those legacy codes and systems in tact. Because of the component-based architecture, all selected procedures can be registered or de-registered at run-time, and are completely reusable, reconfigurable, and modular

    EVALUATING OPTIMAL PRODUCT MIX USING DYNAMIC SIMULATION: A TOMATO PROCESSING CASE

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    Technology-driven change is everywhere and value-capture from new technology is challenging for business managers. Also rival firms may use technology as part of major success strategies. This situation leads managers to be keenly interested in evaluation of alternative technologies prior to making a sunk investment in physical facilities. In contemplating new or added-capacity processing facilities, managers and investors must evaluate return on investment (ROI). Evaluation of ROI is complex because it varies by alternative technology and the resultant potential product mix alternatives associated with that technology at the time the investment capital is committed to build the processing plant. This research examines optimal alternative product mix from a processing plant technology that is fixed at the time of commitment to building or adding capacity. Evaluating the optimal product mix is of vital concern in any start-up processing environment. In this research the optimal product mix is evaluated by using a sophisticated evaluative tool known as PowerSim. This economic simulation software is used to model a start-up tomato processing plant in Ohio. The model evaluates the effects of various output, or tomato product mix, on plant profitability measured by ROI. Results indicate that an increase in plant profitability is expected when the tomato product mix consists of products that have a lower soluble solids concentration. The lower the soluble solids concentration of a tomato product, the less the processor will benefit from tomato varieties with high soluble solids. The processing operation achieves a RIO of 26.5 percent when the plant'Â’s product mix is 50 percent tomato paste (31 degrees brix) and 50 percent diced tomatoes. This product mix optimizes processor net income and realizes a plant return on equity of 50.6 percent.Agribusiness,

    Editors\u27 Note

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    In this issue of Educational Considerations, we are pleased to offer readers extended, in-depth discussions of two critical issues for educational leaders and policymakers: Cost-effective factors that have the potential to improve student achievement and effective preparation programs for education leaders
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