5,413 research outputs found
Universal Codes from Switching Strategies
We discuss algorithms for combining sequential prediction strategies, a task
which can be viewed as a natural generalisation of the concept of universal
coding. We describe a graphical language based on Hidden Markov Models for
defining prediction strategies, and we provide both existing and new models as
examples. The models include efficient, parameterless models for switching
between the input strategies over time, including a model for the case where
switches tend to occur in clusters, and finally a new model for the scenario
where the prediction strategies have a known relationship, and where jumps are
typically between strongly related ones. This last model is relevant for coding
time series data where parameter drift is expected. As theoretical ontributions
we introduce an interpolation construction that is useful in the development
and analysis of new algorithms, and we establish a new sophisticated lemma for
analysing the individual sequence regret of parameterised models
State aid, open access and market size: two cases of fith network implementation in Dutch municipalities
Comorbidity in knee osteoarthritis:Development and evaluation of tailored exercise therapy
Dekker, J. [Promotor]Lems, W.F. [Promotor]Leeden, M. van der [Copromotor]Roorda, L.D. [Copromotor
Induction methods used in low temperature physics
A study has been made of induction bridges used in low temperature physics.\ud
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In Part 1 the design of a mutual inductance bridge of the Hartshorn type is discussed. This design is based on a critical analysis of impurity effects of the different parts of the Hartshorn bridge. With this equipment frequencies up to 0.5 MHz can be used. Two methods have been developed to examine the secondary signal. In one of these use has been made of AD conversion techniques. In the other one, the secondary signal, produced by a superconducting sample, which is generally distorted, is analysed by using a Fourier expansion.\ud
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In Part 2 equipment is described which enables us to measure the phase and amplitude of the harmonics of the output signal of the bridge. For synchronous detection a reference signal of the same frequency of the harmonic of interest is required. This reference signal is generated from the input signal of the bridge by means of a digital frequency multiplier with programmable multiplication factor N.\ud
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In Part 3 some experimental results, showing the possibilities of the equipment, on some superconductors are presented
Adaptive Hedge
Most methods for decision-theoretic online learning are based on the Hedge
algorithm, which takes a parameter called the learning rate. In most previous
analyses the learning rate was carefully tuned to obtain optimal worst-case
performance, leading to suboptimal performance on easy instances, for example
when there exists an action that is significantly better than all others. We
propose a new way of setting the learning rate, which adapts to the difficulty
of the learning problem: in the worst case our procedure still guarantees
optimal performance, but on easy instances it achieves much smaller regret. In
particular, our adaptive method achieves constant regret in a probabilistic
setting, when there exists an action that on average obtains strictly smaller
loss than all other actions. We also provide a simulation study comparing our
approach to existing methods.Comment: This is the full version of the paper with the same name that will
appear in Advances in Neural Information Processing Systems 24 (NIPS 2011),
2012. The two papers are identical, except that this version contains an
extra section of Additional Materia
Surface-micromachined Ta–Si–N beams for use in micromechanics
Realization and characterization of free-standing surface-microstructures based on Ta-Si-N films are presented. Due to their significant physical and chemical properties, such ternary films are promising candidates for application in microelectromechanical devices
xTAS and ThemeStreams:Extendable Text Analysis Service and its Usage in a Topic Monitoring Tool
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