763 research outputs found

    Searching for rewards in graph-structured spaces

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    How do people generalize and explore structured spaces? We study human behavior on a multi-armed bandit task, where rewards are influenced by the connectivity structure of a graph. A detailed predictive model comparison shows that a Gaussian Process regression model using a diffusion kernel is able to best describe participant choices, and also predict judgments about expected reward and confidence. This model unifies psychological models of function learning with the Successor Representation used in reinforcement learning, thereby building a bridge between different models of generalization

    California Methanol Assessment; Volume II, Technical Report

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    A joint effort by the Jet Propulsion Laboratory and the California Institute of Technology Division of Chemistry and Chemical Engineering has brought together sponsors from both the public and private sectors for an analysis of the prospects for methanol use as a fuel in California, primarily for the transportation and stationary application sectors. Increasing optimism in 1982 for a slower rise in oil prices and a more realistic understanding of the costs of methanol production have had a negative effect on methanol viability in the near term (before the year 2000). Methanol was determined to have some promise in the transportation sector, but is not forecasted for large-scale use until beyond the year 2000. Similarly, while alternative use of methanol can have a positive effect on air quality (reducing NOx, SOx, and other emissions), a best case estimate is for less than 4% reduction in peak ozone by 2000 at realistic neat methanol vehicle adoption rates. Methanol is not likely to be a viable fuel in the stationary application sector because it cannot compete economically with conventional fuels except in very limited cases. On the production end, it was determined that methanol produced from natural gas will continue to dominate supply options through the year 2000, and the present and planned industry capacity is somewhat in excess of all projected needs. Nonsubsidized coal-based methanol cannot compete with conventional feedstocks using current technology, but coal-based methanol has promise in the long term (after the year 2000), providing that industry is willing to take the technical and market risks and that government agencies will help facilitate the environment for methanol. Given that the prospects for viable major markets (stationary applications and neat fuel in passenger cars) are unlikely in the 1980s and early 1990s, the next steps for methanol are in further experimentation and research of production and utilization technologies, expanded use as an octane enhancer, and selected fleet implementation. In the view of the study, it is not advantageous at this time to establish policies within California that attempt to expand methanol use rapidly as a neat fuel for passenger cars or to induce electric utility use of methanol on a widespread basis

    California methanol assessment. Volume 1: Summary report

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    The near term methanol industry, the competitive environment, long term methanol market, the transition period, air quality impacts of methanol, roles of the public and private sectors are considered

    Separation and Sealing of a Sample Container Using Brazing

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    A special double-wall container and a process for utilizing the container are being developed to enable (1) acquisition of a sample of material in a dirty environment that may include a biological and/or chemical hazard; (2) sealing a lid onto the inner part of the container to hermetically enclose the sample; (3) separating the resulting hermetic container from the dirty environment; and (4) bringing that hermetic container, without any biological or chemical contamination of its outer surface, into a clean environment. The process is denoted S(exp 3)B (separation, seaming, and sealing using brazing) because sealing of the sample into the hermetic container, separating the container from the dirty environment, and bringing the container with a clean outer surface into the clean environment are all accomplished simultaneously with a brazing operation

    Year-End Individual Taxation Report

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    Several actions by Congress and the IRS aimed to reduce improper claims of the earned income tax credit by increasing preparer penalties and due diligence procedures. * Litigation over restricted stock-based compensation focused on the proper date of the stock\u27s market valuation and the effect of company and SEC restrictions on disposition of the stock. * The Tax Court applied the IRS\u27s recent practice of allowing professional gamblers to deduct ordinary and reasonable nonwagering business expenses over their gambling winnings, overturning a 1951 case holding. * The Tax Court also held that limited partners of a limited partnership who perform services for the partnership in their capacity as partners may be liable for self-employment taxes despite a general statutory exemption from self-employment income for limited partners\u27 income. Reprinted by permission of the publisher

    Structure of the Current Sheet in the 11 July 2017 Electron Diffusion Region Event.

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    The structure of the current sheet along the Magnetospheric Multiscale (MMS) orbit is examined during the 11 July 2017 Electron Diffusion Region (EDR) event. The location of MMS relative to the X-line is deduced and used to obtain the spatial changes in the electron parameters. The electron velocity gradient values are used to estimate the reconnection electric field sustained by nongyrotropic pressure. It is shown that the observations are consistent with theoretical expectations for an inner EDR in 2-D reconnection. That is, the magnetic field gradient scale, where the electric field due to electron nongyrotropic pressure dominates, is comparable to the gyroscale of the thermal electrons at the edge of the inner EDR. Our approximation of the MMS observations using a steady state, quasi-2-D, tailward retreating X-line was valid only for about 1.4 s. This suggests that the inner EDR is localized; that is, electron outflow jet braking takes place within an ion inertia scale from the X-line. The existence of multiple events or current sheet processes outside the EDR may play an important role in the geometry of reconnection in the near-Earth magnetotail
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