2,942 research outputs found
Lie algebras with given properties of subalgebras and elements
Results about the following classes of finite-dimensional Lie algebras over a
field of characteristic zero are presented: anisotropic (i.e., Lie algebras for
which each adjoint operator is semisimple), regular (i.e., Lie algebras in
which each nonzero element is regular in the sense of Bourbaki), minimal
nonabelian (i.e., nonabelian Lie algebras all whose proper subalgebras are
abelian), and algebras of depth 2 (i.e., Lie algebras all whose proper
subalgebras are abelian or minimal nonabelian).Comment: 8 pages; v3: added proofs; fixed a list of algebras of depth 2 in
Theorem 7; the statement of Theorem 5 is weakened, the former statement added
as conjecture; to appear in Proceedings of the Conference "Algebra - Geometry
- Mathematical Physics" (Mulhouse, 2011), Springer Proc. Math. Sta
Update of High Resolution (e,e'K^+) Hypernuclear Spectroscopy at Jefferson Lab's Hall A
Updated results of the experiment E94-107 hypernuclear spectroscopy in Hall A
of the Thomas Jefferson National Accelerator Facility (Jefferson Lab), are
presented. The experiment provides high resolution spectra of excitation energy
for 12B_\Lambda, 16N_\Lambda, and 9Li_\Lambda hypernuclei obtained by
electroproduction of strangeness. A new theoretical calculation for
12B_\Lambda, final results for 16N_\Lambda, and discussion of the preliminary
results of 9Li_\Lambda are reported.Comment: 8 pages, 5 figures, submitted to the proceedings of Hyp-X Conferenc
An illustration of new methods in machine condition monitoring, Part I: Stochastic resonance
There have been many recent developments in the application of data-based
methods to machine condition monitoring. A powerful methodology based on machine learning
has emerged, where diagnostics are based on a two-step procedure: extraction of damage sensitive
features, followed by unsupervised learning (novelty detection) or supervised learning
(classification). The objective of the current pair of papers is simply to illustrate one state-of the-art
procedure for each step, using synthetic data representative of reality in terms of size
and complexity. The first paper in the pair will deal with feature extraction.
Although some papers have appeared in the recent past considering stochastic resonance
as a means of amplifying damage information in signals, they have largely relied on ad hoc
specifications of the resonator used. In contrast, the current paper will adopt a principled
optimisation-based approach to the resonator design. The paper will also show that a discrete
dynamical system can provide all the benefits of a continuous system, but also provide a
considerable speed-up in terms of simulation time in order to facilitate the optimisation
approach
An Illustration of New Methods in Machine Condition Monitoring, Part II: Adaptive outlier detection
There have been many recent developments in the application of data-based
methods to machine condition monitoring. A powerful methodology based on machine learning
has emerged, where diagnostics are based on a two-step procedure: extraction of damagesensitive
features, followed by unsupervised learning (novelty detection) or supervised learning
(classification). The objective of the current pair of papers is simply to illustrate one state-ofthe-art
procedure for each step, using synthetic data representative of reality in terms of size
and complexity. The second paper in the pair will deal with novelty detection. Although there
has been considerable progress in the use of outlier analysis for novelty detection, most of the
papers produced so far have suffered from the fact that simple algorithms break down if multiple
outliers are present or if damage is already present in a training set. The objective of the current
paper is to illustrate the use of phase-space thresholding; an algorithm which has the ability to
detect multiple outliers inclusively in a data set
Statistical equilibrium in simple exchange games I
Simple stochastic exchange games are based on random allocation of finite
resources. These games are Markov chains that can be studied either
analytically or by Monte Carlo simulations. In particular, the equilibrium
distribution can be derived either by direct diagonalization of the transition
matrix, or using the detailed balance equation, or by Monte Carlo estimates. In
this paper, these methods are introduced and applied to the
Bennati-Dragulescu-Yakovenko (BDY) game. The exact analysis shows that the
statistical-mechanical analogies used in the previous literature have to be
revised.Comment: 11 pages, 3 figures, submitted to EPJ
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