927 research outputs found

    Competition and cooperation: Libraries and publishers in the transition to electronic scholarly journals

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    The conversion of scholarly journals to digital format is proceeding rapidly, especially for those from large commercial and learned society publishers. This conversion offers the best hope for survival for such publishers. The infamous "journal crisis" is more of a library cost crisis than a publisher pricing problem, with internal library costs much higher than the amount spent on purchasing books and journals. Therefore publishers may be able to retain or even increase their revenues and profits, while at the same time providing a superior service. To do this, they will have to take over many of the function of libraries, and they can do that only in the digital domain. This paper examines publishers' strategies, how they are likely to evolve, and how they will affect libraries

    Too Expensive to Meter: The influence of transaction costs in transportation and communication

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    Technology appears to be making fine-scale charging (as in tolls on roads that depend on time of day or even on current and anticipated levels of congestion) increasingly feasible. And such charging appears to be increasingly desirable, as traffic on roads continues to grow, and costs and public opposition limit new construction. Similar incentives towards fine-scale charging also appear to be operating in communications and other areas, such as electricity usage. Standard economic theory supports such measures, and technology is being developed and deployed to implement them. But their spread is not very rapid, and prospects for the future are uncertain. This paper presents a collection of sketches, some from ancient history, some from current developments, that illustrate the costs that charging imposes. Some of those costs are explicit (in terms of the monetary costs to users, and the costs of implementing the charging mechanisms). Others are implicit, such as the time or the mental processing costs of users. These argue that the case for fine-scale charging is not unambiguous, and that in many cases may be inappropriate.transportation, communication, transaction costs, collection costs

    Numerical study of the derivative of the Riemann zeta function at zeros

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    The derivative of the Riemann zeta function was computed numerically on several large sets of zeros at large heights. Comparisons to known and conjectured asymptotics are presented.Comment: 13 pages, 5 figures; minor typos fixe

    The zeta function on the critical line: Numerical evidence for moments and random matrix theory models

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    Results of extensive computations of moments of the Riemann zeta function on the critical line are presented. Calculated values are compared with predictions motivated by random matrix theory. The results can help in deciding between those and competing predictions. It is shown that for high moments and at large heights, the variability of moment values over adjacent intervals is substantial, even when those intervals are long, as long as a block containing 10^9 zeros near zero number 10^23. More than anything else, the variability illustrates the limits of what one can learn about the zeta function from numerical evidence. It is shown the rate of decline of extreme values of the moments is modelled relatively well by power laws. Also, some long range correlations in the values of the second moment, as well as asymptotic oscillations in the values of the shifted fourth moment, are found. The computations described here relied on several representations of the zeta function. The numerical comparison of their effectiveness that is presented is of independent interest, for future large scale computations.Comment: 31 pages, 10 figures, 19 table

    Exact asymptotics of monomer-dimer model on rectangular semi-infinite lattices

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    By using the asymptotic theory of Pemantle and Wilson, exact asymptotic expansions of the free energy of the monomer-dimer model on rectangular n×n \times \infty lattices in terms of dimer density are obtained for small values of nn, at both high and low dimer density limits. In the high dimer density limit, the theoretical results confirm the dependence of the free energy on the parity of nn, a result obtained previously by computational methods. In the low dimer density limit, the free energy on a cylinder n×n \times \infty lattice strip has exactly the same first nn terms in the series expansion as that of infinite ×\infty \times \infty lattice.Comment: 9 pages, 6 table

    What would surprise early Victorian market players if they came alive today?

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    Perhaps the greatest surprise would be the combination of high equity prices and low long-term interest rates, writes Andrew Odlyzk

    Rapid computation of L-functions for modular forms

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    Let ff be a fixed (holomorphic or Maass) modular cusp form, with LL-function L(f,s)L(f,s). We describe an algorithm that computes the value L(f,1/2+iT)L(f,1/2+ iT) to any specified precision in time O(1+T7/8)O(1+|T|^{7/8})

    Pushing BitTorrent Locality to the Limit

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    Peer-to-peer (P2P) locality has recently raised a lot of interest in the community. Indeed, whereas P2P content distribution enables financial savings for the content providers, it dramatically increases the traffic on inter-ISP links. To solve this issue, the idea to keep a fraction of the P2P traffic local to each ISP was introduced a few years ago. Since then, P2P solutions exploiting locality have been introduced. However, several fundamental issues on locality still need to be explored. In particular, how far can we push locality, and what is, at the scale of the Internet, the reduction of traffic that can be achieved with locality? In this paper, we perform extensive experiments on a controlled environment with up to 10 000 BitTorrent clients to evaluate the impact of high locality on inter-ISP links traffic and peers download completion time. We introduce two simple mechanisms that make high locality possible in challenging scenarios and we show that we save up to several orders of magnitude inter-ISP traffic compared to traditional locality without adversely impacting peers download completion time. In addition, we crawled 214 443 torrents representing 6 113 224 unique peers spread among 9 605 ASes. We show that whereas the torrents we crawled generated 11.6 petabytes of inter-ISP traffic, our locality policy implemented for all torrents would have reduced the global inter-ISP traffic by 40%

    Efficient implementation of the Hardy-Ramanujan-Rademacher formula

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    We describe how the Hardy-Ramanujan-Rademacher formula can be implemented to allow the partition function p(n)p(n) to be computed with softly optimal complexity O(n1/2+o(1))O(n^{1/2+o(1)}) and very little overhead. A new implementation based on these techniques achieves speedups in excess of a factor 500 over previously published software and has been used by the author to calculate p(1019)p(10^{19}), an exponent twice as large as in previously reported computations. We also investigate performance for multi-evaluation of p(n)p(n), where our implementation of the Hardy-Ramanujan-Rademacher formula becomes superior to power series methods on far denser sets of indices than previous implementations. As an application, we determine over 22 billion new congruences for the partition function, extending Weaver's tabulation of 76,065 congruences.Comment: updated version containing an unconditional complexity proof; accepted for publication in LMS Journal of Computation and Mathematic
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