927 research outputs found
Competition and cooperation: Libraries and publishers in the transition to electronic scholarly journals
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
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
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
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
By using the asymptotic theory of Pemantle and Wilson, exact asymptotic
expansions of the free energy of the monomer-dimer model on rectangular lattices in terms of dimer density are obtained for small values
of , 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 , a result obtained previously by computational methods. In the
low dimer density limit, the free energy on a cylinder
lattice strip has exactly the same first terms in the series expansion as
that of infinite lattice.Comment: 9 pages, 6 table
What would surprise early Victorian market players if they came alive today?
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
Let be a fixed (holomorphic or Maass) modular cusp form, with
-function . We describe an algorithm that computes the value
to any specified precision in time
Pushing BitTorrent Locality to the Limit
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
We describe how the Hardy-Ramanujan-Rademacher formula can be implemented to
allow the partition function to be computed with softly optimal
complexity 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
, an exponent twice as large as in previously reported
computations.
We also investigate performance for multi-evaluation of , 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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