60,228 research outputs found

    From Cooperative Scans to Predictive Buffer Management

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    In analytical applications, database systems often need to sustain workloads with multiple concurrent scans hitting the same table. The Cooperative Scans (CScans) framework, which introduces an Active Buffer Manager (ABM) component into the database architecture, has been the most effective and elaborate response to this problem, and was initially developed in the X100 research prototype. We now report on the the experiences of integrating Cooperative Scans into its industrial-strength successor, the Vectorwise database product. During this implementation we invented a simpler optimization of concurrent scan buffer management, called Predictive Buffer Management (PBM). PBM is based on the observation that in a workload with long-running scans, the buffer manager has quite a bit of information on the workload in the immediate future, such that an approximation of the ideal OPT algorithm becomes feasible. In the evaluation on both synthetic benchmarks as well as a TPC-H throughput run we compare the benefits of naive buffer management (LRU) versus CScans, PBM and OPT; showing that PBM achieves benefits close to Cooperative Scans, while incurring much lower architectural impact.Comment: VLDB201

    Charles M. Breder, Jr.: Bahamas and Florida

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    Dr. Charles M. Breder, a well known ichthyologist, kept meticulous field diaries throughout his career. This publication is a transcription of field notes recorded during the Bacon Andros Expeditions, and trips to Florida, Ohio and Illinois during the 1930s. Breder's work in Andros included exploration of a "blue hole", inland ecosystems, and collection of marine and terrestrial specimens. Anecdotes include descriptions of camping on the beach, the "filly-mingoes" (flamingos) of Andros Island, the Marine Studios of Jacksonville, FL, a trip to Havana, and the birth of seahorses. This publication is part of a series of transcriptions of Dr. Breder's diaries. (PDF contains 55 pages

    Give Me Your Entrepreneurs, Your Innovators: Estimating the Employment Impact of a Startup Visa

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    The idea of visas for immigrant entrepreneurs has bounced around the country for many years, and even has been introduced into Congress on more than one occasion. The most recent is Startup Act 3.0, a bipartisan bill recently introduced into the U.S. Senate that, among other things, includes a Startup Visa. In this current incarnation, the new Startup Visa would make available a fixed pot of 75,000 visas for individuals who start companies. Initial eligibility would be restricted to individuals who already are in the United States on either H-1B visas or F-1 student visas. Once the Startup Visa is issued, further requirements are imposed in the first year. During that time, the entrepreneur must register a business, employ at least two full-time, non-family employees, and invest or raise an investment of at least $100,000. If, after one year, those requirements are met, the entrepreneur gets three additional years on the visa. During that three-year period, the entrepreneur must employ at least five full-time, non-family employees. The original two employees count toward these five, which means the business essentially must hire one person per year after the first year of operation. At the end of three years, the entrepreneur may apply to have the conditional status removed.This report attempts to estimate the impact on job creation that enactment of such a Startup Visa would have. Calculations suggest that a Startup Visa could create anywhere from 500,000 to 1.6 million jobs over the next ten years. Because of the assumptions and methods used, these estimates are considered very conservative, low-end estimates

    The New Hampshire, Vol. 106, No. 09 (Oct. 3, 2016)

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    An independent student produced newspaper from the University of New Hampshire

    Deep End

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    System dynamics advances strategic economic transition planning in a developing nation

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    The increasingly complex environment of today's world, characterized by technological innovation and global communication, generates myriads of possible and actual interactions while limited physical and intellectual resources severely impinge on decision makers, be it in the public or private domains. At the core of the decision-making process is the need for quality information that allows the decision maker to better assess the impact of decisions in terms of outcomes, nonlinear feedback processes and time delays on the performance of the complex system invoked. This volume is a timely review on the principles underlying complex decision making, the handling of uncertainties in dynamic envrionments and of the various modeling approaches used. The book consists of five parts, each composed of several chapters: I: Complex Decision Making: Concepts, Theories and Empirical Evidence II: Tools and Techniques for Decision Making in Complex Environments and Systems III: System Dynamics and Agent-Based Modeling IV: Methodological Issues V: Future Direction

    Can Asset Markets Be Manipulated? A Field Experiment With Racetrack Betting

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    To test whether naturally occurring markets can be strategically manipulated, 500and500 and 1,000 bets were made, then canceled, at horse racing tracks. The net effects of these costless temporary bets give clues about how market participants react to information large bets might contain. The bets moved odds on horses visibly (compared to matched‐pair control horses with similar prebet odds) and had a slight tendency to draw money toward the horse that was temporarily bet, but the net effect was close to zero and statistically insignificant. The results suggest that some bettors inferred information from bets and others did not, and their reactions roughly canceled out

    Spartan Daily, April 7, 2009

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    Volume 132, Issue 34https://scholarworks.sjsu.edu/spartandaily/10571/thumbnail.jp
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