6,502 research outputs found
Cursive script recognition using wildcards and multiple experts
Variability in handwriting styles suggests that many letter recognition engines cannot correctly identify some hand-written letters of poor quality at reasonable computational cost. Methods that are capable of searching the resulting sparse graph of letter candidates are therefore required. The method presented here employs âwildcardsâ to represent missing letter candidates. Multiple experts are used to represent different aspects of handwriting. Each expert evaluates closeness of match and indicates its confidence. Explanation experts determine the degree to which the word alternative under consideration explains extraneous letter candidates. Schemata for normalisation and combination of scores are investigated and their performance compared. Hill climbing yields near-optimal combination weights that outperform comparable methods on identical dynamic handwriting data
A method to correct differential nonlinearities in subranging analog-to-digital converters used for digital gamma-ray spectroscopy
The influence on -ray spectra of differential nonlinearities (DNL) in
subranging, pipelined analog-to-digital converts (ADCs) used for digital
-ray spectroscopy was investigated. The influence of the DNL error on
the -ray spectra, depending on the input count-rate and the dynamic
range has been investigated systematically. It turned out, that the DNL becomes
more significant in -ray spectra with larger dynamic range of the
spectroscopy system. An event-by-event offline correction algorithm was
developed and tested extensively. This correction algorithm works especially
well for high dynamic ranges
Directed transport of two interacting particles in a washboard potential
We study the conservative and deterministic dynamics of two nonlinearly
interacting particles evolving in a one-dimensional spatially periodic
washboard potential. A weak tilt of the washboard potential is applied biasing
one direction for particle transport. However, the tilt vanishes asymptotically
in the direction of bias. Moreover, the total energy content is not enough for
both particles to be able to escape simultaneously from an initial potential
well; to achieve transport the coupled particles need to interact
cooperatively. For low coupling strength the two particles remain trapped
inside the starting potential well permanently. For increased coupling strength
there exists a regime in which one of the particles transfers the majority of
its energy to the other one, as a consequence of which the latter escapes from
the potential well and the bond between them breaks. Finally, for suitably
large couplings, coordinated energy exchange between the particles allows them
to achieve escapes -- one particle followed by the other -- from consecutive
potential wells resulting in directed collective motion. The key mechanism of
transport rectification is based on the asymptotically vanishing tilt causing a
symmetry breaking of the non-chaotic fraction of the dynamics in the mixed
phase space. That is, after a chaotic transient, only at one of the boundaries
of the chaotic layer do resonance islands appear. The settling of trajectories
in the ballistic channels associated with transporting islands provides
long-range directed transport dynamics of the escaping dimer
Probabilistic Numerics and Uncertainty in Computations
We deliver a call to arms for probabilistic numerical methods: algorithms for
numerical tasks, including linear algebra, integration, optimization and
solving differential equations, that return uncertainties in their
calculations. Such uncertainties, arising from the loss of precision induced by
numerical calculation with limited time or hardware, are important for much
contemporary science and industry. Within applications such as climate science
and astrophysics, the need to make decisions on the basis of computations with
large and complex data has led to a renewed focus on the management of
numerical uncertainty. We describe how several seminal classic numerical
methods can be interpreted naturally as probabilistic inference. We then show
that the probabilistic view suggests new algorithms that can flexibly be
adapted to suit application specifics, while delivering improved empirical
performance. We provide concrete illustrations of the benefits of probabilistic
numeric algorithms on real scientific problems from astrometry and astronomical
imaging, while highlighting open problems with these new algorithms. Finally,
we describe how probabilistic numerical methods provide a coherent framework
for identifying the uncertainty in calculations performed with a combination of
numerical algorithms (e.g. both numerical optimisers and differential equation
solvers), potentially allowing the diagnosis (and control) of error sources in
computations.Comment: Author Generated Postprint. 17 pages, 4 Figures, 1 Tabl
Exploiting zoning based on approximating splines in cursive script recognition
Because of its complexity, handwriting recognition has to exploit many sources of information to be successful, e.g. the handwriting zones. Variability of zone-lines, however, requires a more flexible representation than traditional horizontal or linear methods. The proposed method therefore employs approximating cubic splines. Using entire lines of text rather than individual words is shown to improve the zoning accuracy, especially for short words. The new method represents an improvement over existing methods in terms of range of applicability, zone-line precision and zoning-classification accuracy. Application to several problems of handwriting recognition is demonstrated and evaluated
Emergence of continual directed flow in Hamiltonian systems
We propose a minimal model for the emergence of a directed flow in autonomous
Hamiltonian systems. It is shown that internal breaking of the spatio-temporal
symmetries, via localised initial conditions, that are unbiased with respect to
the transporting degree of freedom, and transient chaos conspire to form the
physical mechanism for the occurrence of a current. Most importantly, after
passage through the transient chaos, trajectories perform solely regular
transporting motion so that the resulting current is of continual ballistic
nature. This has to be distinguished from the features of transport reported
previously for driven Hamiltonian systems with mixed phase space where
transport is determined by intermittent behaviour exhibiting power-law decay
statistics of the duration of regular ballistic periods
Incomplete and Asymmetric Surplus Information in Labor Relations
Numerous laboratory experiments show that workers reciprocate to high wages with high effort, when there is perfect information on the surplus created. Recent field experiments, however, suggest that trust and reciprocity may be lower or absent when the information is incomplete.We report a laboratory experiment with symmetric and asymmetric incomplete surplus information in a bilateral gift exchange setting.We find that trust and reciprocity have a significant positive effect on wages, effort and efficiency.But, all three are substantially lower under incomplete than under complete information.The negative impact on wages and efficiency is even greater with information asymmetry.incomplete information;industrial relations;trusts;efficiency
Nonlinear response of a linear chain to weak driving
We study the escape of a chain of coupled units over the barrier of a
metastable potential. It is demonstrated that a very weak external driving
field with suitably chosen frequency suffices to accomplish speedy escape. The
latter requires the passage through a transition state the formation of which
is triggered by permanent feeding of energy from a phonon background into humps
of localised energy and elastic interaction of the arising breather solutions.
In fact, cooperativity between the units of the chain entailing coordinated
energy transfer is shown to be crucial for enhancing the rate of escape in an
extremely effective and low-energy cost way where the effect of entropic
localisation and breather coalescence conspire
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