14,220,390 research outputs found
Low x particle spectra in the Modified Leading Logarithm Approximation
We show that the higher moments of the evolution obtained from the Modified
Leading Logarithm Approximation may be regarded as spurious higher order terms
in perturbation theory, and that neglecting them leads to a good description of
the data around and above the peak in . Furthermore, we use this
study of the moments to show that at high energy the Limiting Spectrum with
Local Parton-Hadron Duality may also be derived from the Modified Leading
Logarithm Approximation without any non-perturbative assumptions.Comment: Submitted to Eur. Phys. J.,
Fast Algorithms and Efficient Statistics: N-point Correlation Functions
We present here a new algorithm for the fast computation of N-point
correlation functions in large astronomical data sets. The algorithm is based
on kdtrees which are decorated with cached sufficient statistics thus allowing
for orders of magnitude speed-ups over the naive non-tree-based implementation
of correlation functions. We further discuss the use of controlled
approximations within the computation which allows for further acceleration. In
summary, our algorithm now makes it possible to compute exact, all-pairs,
measurements of the 2, 3 and 4-point correlation functions for cosmological
data sets like the Sloan Digital Sky Survey (SDSS; York et al. 2000) and the
next generation of Cosmic Microwave Background experiments (see Szapudi et al.
2000).Comment: To appear in Proceedings of MPA/MPE/ESO Conference "Mining the Sky",
July 31 - August 4, 2000, Garching, German
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Wired warfare 3.0: protecting the civilian population during cyber operations
As a general matter, international humanitarian law is up to the task of providing the legal framework for cyber operations during an armed conflict. However, two debates persist in this regard, the resolution of which will determine the precise degree of protection the civilian population will enjoy during cyber operations. The first revolves around the meaning of the term “attack” in various conduct of hostilities rules, while the second addresses the issue of whether data may be considered an object such that operations destroying or altering it are subject to the prohibition on attacking civilian objects and that such effects need be considered when considering proportionality and the taking of precautions in attack. Even if these debates were to be resolved, the civilian population would still face risks from the unique capabilities of cyber operations. This article proposes two policies which parties to a conflict should consider adopting in order to ameliorate such risks. They are both based on the premise that military operations must reflect a balance between military concerns and the interest of States in prevailing in the conflict
Hopf Bifurcation and Chaos in a Single Inertial Neuron Model with Time Delay
A delayed differential equation modelling a single neuron with inertial term
is considered in this paper. Hopf bifurcation is studied by using the normal
form theory of retarded functional differential equations. When adopting a
nonmonotonic activation function, chaotic behavior is observed. Phase plots,
waveform plots, and power spectra are presented to confirm the chaoticity.Comment: 12 pages, 7 figure
Fixed Parameter Undecidability for Wang Tilesets
Deciding if a given set of Wang tiles admits a tiling of the plane is
decidable if the number of Wang tiles (or the number of colors) is bounded, for
a trivial reason, as there are only finitely many such tilesets. We prove
however that the tiling problem remains undecidable if the difference between
the number of tiles and the number of colors is bounded by 43.
One of the main new tool is the concept of Wang bars, which are equivalently
inflated Wang tiles or thin polyominoes.Comment: In Proceedings AUTOMATA&JAC 2012, arXiv:1208.249
What similar physical processes occur on both Earth and Mars?
This NASA Module investigation compares and contrasts physical processes that occur on Both Earth and Mars. Students are given unidentified images of Earth and Mars. Their task is to arrange the images into pairs that show evidence of similar physical processes. Then they identify each image as one of Earth or of Mars by comparing and contrasting physical features that they observe in the image pairs. It includes teacher background materials and an answer key where appropriate. Educational levels: High school, Middle school
Connection system
A mechanical connection system comprises a first body defining a receptable and a second body defining a pin matingly receivable in the receptacle by relative movement in a first directional mode. A primary latch is engagable between the two bodies to retain the pin in the receptacle. The primary latch is reciprocable in a second directional mode transverse to the first directional mode. A lock member carried by one of the bodies is operatively associated with the primary latch and movable, transverse to the second directional mode, between a locking position maintaining engagement of the primary latch and a releasing position permitting release of the primary latch. The lock includes an operator portion engagable to move the lock member from its locking position to its releasing position. The operator is located internally of the first body. An actuator is selectivity insertable into and disengagable from the first body. The actuator is movable relative to the first body when it is inserted for engagement with and operation of the operator
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