1,784,466 research outputs found
Internet Predictions
More than a dozen leading experts give their opinions on where the Internet is headed and where it will be in the next decade in terms of technology, policy, and applications. They cover topics ranging from the Internet of Things to climate change to the digital storage of the future. A summary of the articles is available in the Web extras section
Analogical Predictions
This paper deals with exchangeable analogical predictions,\ud
and proposes a Bayesian model for such predictions.\ud
The paper first discerns two kinds of analogical\ud
predictions, based on similarity of individuals and of types\ud
respectively. It then introduces a Bayesian framework that\ud
employs hypotheses for making predictions. This framework\ud
is used to describe predictions based on the similarity\ud
of individuals, and further relates exchangeable predictions\ud
with a specific partition of hypotheses on types. Exchangeable\ud
predictions based on type similarity are determined by\ud
prior probabilities over the partition, but the partition obstructs\ud
the control over the similarity relations. Finally the\ud
paper develops a model for exchangeable predictions\ud
based on type similarity, which employs hypotheses on\ud
similarity between individuals, thereby offering a better\ud
control over the similarity relations
Unification predictions
The unification of gauge couplings suggests that there is an underlying
(supersymmetric) unification of the strong, electromagnetic and weak
interactions. The prediction of the unification scale may be the first
quantitative indication that this unification may extend to unification with
gravity. We make a precise determination of these predictions for a class of
models which extend the multiplet structure of the Minimal Supersymmetric
Standard Model to include the heavy states expected in many Grand Unified
and/or superstring theories. We show that there is a strong cancellation
between the 2-loop and threshold effects. As a result the net effect is smaller
than previously thought, giving a small increase in both the unification scale
and the value of the strong coupling at low energies.Comment: 20 pages, Latex, 5 Postscipt figures; 2 references adde
Higgs-mass predictions
A compilation of Higgs-mass predictions is proposedComment: This is the last version. Only addition: today's update by Kahana &
Kahan
Towards String Predictions
The aim of superstring phenomenology is to develop the tools and methodology
needed to confront string theory with experimental data. The first mandatory
task is to find string solutions which reproduce the observable data. The
subsequent goal is to extract potential signatures beyond the observable data.
Recently, by studying exact flat directions of non-Abelian singlet fields, we
demonstrated the existence of free fermionic heterotic-string models in which
the -charged matter spectrum, just below the
string scale, consists solely of the MSSM spectrum. In this paper we study the
possibility that the exact flat directions leave a symmetry
unbroken at the Planck scale. We demonstrate in a specific example that such
unbroken is in general expected to be not of the GUT type but
of intrinsic stringy origin. We study its phenomenological characteristics and
the consequences in the case that remains unbroken down to
low energies. We suggest that observation in forthcoming colliders of a
, with universal couplings for the two light generations but
different couplings for the heavy generation may provide evidence for the
orbifold which underlies the free fermionic models.Comment: 18 pages. Standard Latex. References adde
Testing earthquake predictions
Statistical tests of earthquake predictions require a null hypothesis to
model occasional chance successes. To define and quantify `chance success' is
knotty. Some null hypotheses ascribe chance to the Earth: Seismicity is modeled
as random. The null distribution of the number of successful predictions -- or
any other test statistic -- is taken to be its distribution when the fixed set
of predictions is applied to random seismicity. Such tests tacitly assume that
the predictions do not depend on the observed seismicity. Conditioning on the
predictions in this way sets a low hurdle for statistical significance.
Consider this scheme: When an earthquake of magnitude 5.5 or greater occurs
anywhere in the world, predict that an earthquake at least as large will occur
within 21 days and within an epicentral distance of 50 km. We apply this rule
to the Harvard centroid-moment-tensor (CMT) catalog for 2000--2004 to generate
a set of predictions. The null hypothesis is that earthquake times are
exchangeable conditional on their magnitudes and locations and on the
predictions--a common ``nonparametric'' assumption in the literature. We
generate random seismicity by permuting the times of events in the CMT catalog.
We consider an event successfully predicted only if (i) it is predicted and
(ii) there is no larger event within 50 km in the previous 21 days. The
-value for the observed success rate is : The method successfully
predicts about 5% of earthquakes, far better than `chance,' because the
predictor exploits the clustering of earthquakes -- occasional foreshocks --
which the null hypothesis lacks. Rather than condition on the predictions and
use a stochastic model for seismicity, it is preferable to treat the observed
seismicity as fixed, and to compare the success rate of the predictions to the
success rate of simple-minded predictions like those just described. If the
proffered predictions do no better than a simple scheme, they have little
value.Comment: Published in at http://dx.doi.org/10.1214/193940307000000509 the IMS
Collections (http://www.imstat.org/publications/imscollections.htm) by the
Institute of Mathematical Statistics (http://www.imstat.org
Primordial Nucleosynthesis: Accurate Predictions
A new accurate evaluation of primordial light nuclei abundances is presented.
The proton to neutron conversion rates have been corrected to take into account
radiative effects, finite nucleon mass, thermal and plasma corrections. The
theoretical uncertainty on 4He is so reduced to the order of 0.1%.Comment: 4 pages, Talk given at the International Workshop on Particles in
Astrophysics and Cosmology: From Theory to Observation, Valencia 199
Recommended from our members
Universality of Bayesian Predictions
Given the sequential update nature of Bayes rule, Bayesian methods find natural application to prediction problems. Advances in computational methods allow to routinely use Bayesian methods in econometrics. Hence, there is a strong case for feasible predictions in a Bayesian framework. This paper studies the theoretical properties of Bayesian predictions and shows that under minimal conditions we can derive finite sample bounds for the loss incurred using
Bayesian predictions under the Kullback-Leibler divergence. In particular, the concept of universality of predictions is discussed and universality is established for Bayesian predictions in a variety of settings. These include predictions under almost arbitrary loss functions, model
averaging, predictions in a non stationary environment and under model miss-specification.
Given the possibility of regime switches and multiple breaks in economic series, as well as the
need to choose among different forecasting models, which may inevitably be miss-specified, the
finite sample results derived here are of interest to economic and financial forecasting
Assertion, knowledge and predictions
John N. Williams (1994) and Matthew Weiner (2005) invoke predictions in order to undermine the normative relevance of knowledge for assertions; in particular, Weiner argues, predictions are important counterexamples to the Knowledge Account of Assertion (KAA). I argue here that they are not true counterexamples at all, a point that can be agreed upon even by those who reject KAA
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