2,415 research outputs found
On Elo based prediction models for the FIFA Worldcup 2018
We propose an approach for the analysis and prediction of a football
championship. It is based on Poisson regression models that include the Elo
points of the teams as covariates and incorporates differences of team-specific
effects. These models for the prediction of the FIFA World Cup 2018 are fitted
on all football games on neutral ground of the participating teams since 2010.
Based on the model estimates for single matches Monte-Carlo simulations are
used to estimate probabilities for reaching the different stages in the FIFA
World Cup 2018 for all teams. We propose two score functions for ordinal random
variables that serve together with the rank probability score for the
validation of our models with the results of the FIFA World Cups 2010 and 2014.
All models favor Germany as the new FIFA World Champion. All possible courses
of the tournament and their probabilities are visualized using a single Sankey
diagram.Comment: 22 pages, 7 figure
Branching Random Walks on Free Products of Groups
We study certain phase transitions of branching random walks (BRW) on Cayley
graphs of free products. The aim of this paper is to compare the size and
structural properties of the trace, i.e., the subgraph that consists of all
edges and vertices that were visited by some particle, with those of the
original Cayley graph. We investigate the phase when the growth parameter
is small enough such that the process survives but the trace is not
the original graph. A first result is that the box-counting dimension of the
boundary of the trace exists, is almost surely constant and equals the
Hausdorff dimension which we denote by . The main result states
that the function has only one point of discontinuity which is
at where is the radius of convergence of the Green function
of the underlying random walk. Furthermore, is bounded by one half
the Hausdorff dimension of the boundary of the original Cayley graph and the
behaviour of as is classified.
In the case of free products of infinite groups the end-boundary can be
decomposed into words of finite and words of infinite length. We prove the
existence of a phase transition such that if
the end boundary of the trace consists only of infinite words and if
it also contains finite words. In the last case,
the Hausdorff dimension of the set of ends (of the trace and the original
graph) induced by finite words is strictly smaller than the one of the ends
induced by infinite words.Comment: 39 pages, 4 figures; final version, accepted for publication in the
Proceedings of LM
An event-based architecture for solving constraint satisfaction problems
Constraint satisfaction problems (CSPs) are typically solved using
conventional von Neumann computing architectures. However, these architectures
do not reflect the distributed nature of many of these problems and are thus
ill-suited to solving them. In this paper we present a hybrid analog/digital
hardware architecture specifically designed to solve such problems. We cast
CSPs as networks of stereotyped multi-stable oscillatory elements that
communicate using digital pulses, or events. The oscillatory elements are
implemented using analog non-stochastic circuits. The non-repeating phase
relations among the oscillatory elements drive the exploration of the solution
space. We show that this hardware architecture can yield state-of-the-art
performance on a number of CSPs under reasonable assumptions on the
implementation. We present measurements from a prototype electronic chip to
demonstrate that a physical implementation of the proposed architecture is
robust to practical non-idealities and to validate the theory proposed.Comment: First two authors contributed equally to this wor
Screening of winter barley varieties (Hordeum vulgare) for resistance against loose smut (Ustilago nuda) and covered smut (Ustilago hordei) in Germany
Up to now organic farmers depend greatly on conventionally bred and produced varieties of barley. A turning point was set in 2004 by EU regulation No. 1452/2003 restricting the use of conventionally propagated seed and planting material for organic agriculture. Concerning smut fungi in barley, conventional seed producer's attention was rarely directed to plant resistance due to the possibility of chemical seed treatment (controlling the diseases completely). A main problem for organic seed producers is that organically produced seeds have to fulfil the same regular phytosanitary requirements like conventionally produced seeds. For the production of certified seeds not more than five ears infected with Ustilago hordei (Uh) and/or U. nuda (Un) are allowed on an area of 150 m² in Germany (RUTZ 1998). Though warm or hot water treatment can give excellent control of Un and Uh in organic farming (WINTER et al. 1996), the effect is not sufficient for seed production. Even biological control agents (for example Tillecur®) cannot reach the demands of the guidelines reliably. As an effective way to keep the restrictions remains the cultivation of resistant varieties. Aim of the presented study was to screen winter barley varieties for their degree of smut resistance in Germany. It started in 2000 (KLAUSE & SPIESS 2003) and is sponsored within the Federal Organic Farming Scheme since 2002
The Economic Effects of Constitutions: Replicating – and Extending – Persson and Tabellini
Persson and Tabellini (2003) show that presidential regimes and majoritarian election systems have important effects on fiscal policy, government effectiveness and productivity. Here, their dataset is extended in a number of ways: the number of countries included is increased from 85 to up to 116, and more recent data for both government effectiveness and productivity are used. In replicating and extending their analyses, we find that the effect of presidential regimes on all three groups of economic variables vanishes almost entirely. With regard to electoral systems, the original results are largely confirmed: majoritarian (as opposed to proportional) electoral systems lead to lower government expenditure, lower levels of rent seeking but also lower output per worker. The institutional details such as the proportion of candidates that are not elected via party lists and the district magnitude have proved to be of particular importance. The question whether societies can improve their lot by choosing specific constitutional rules remains open.
User-Centric Monitoring and Steering of the Execution of Large Job Sets
Processing of large data sets with high through put is one of the major focus of Grid computing today. If possible, data are split up into small chunks that are processed independently. Thus, job sets of hundreds > or even thousands of individual jobs are possible. For the job submitter or the resource providers such a scenario is a nightmare currently, as it is hard to keep track of such an amount of jobs or to identify failure reasons. We present a system that will support gLite users to track and monitor their jobs and their resource usage, to nd and identify failure reasons and even to steer running applications
Preemptively Pruning Clever-Hans Strategies in Deep Neural Networks
Robustness has become an important consideration in deep learning. With the
help of explainable AI, mismatches between an explained model's decision
strategy and the user's domain knowledge (e.g. Clever Hans effects) have been
identified as a starting point for improving faulty models. However, it is less
clear what to do when the user and the explanation agree. In this paper, we
demonstrate that acceptance of explanations by the user is not a guarantee for
a machine learning model to be robust against Clever Hans effects, which may
remain undetected. Such hidden flaws of the model can nevertheless be
mitigated, and we demonstrate this by contributing a new method,
Explanation-Guided Exposure Minimization (EGEM), that preemptively prunes
variations in the ML model that have not been the subject of positive
explanation feedback. Experiments demonstrate that our approach leads to models
that strongly reduce their reliance on hidden Clever Hans strategies, and
consequently achieve higher accuracy on new data.Comment: 18 pages + supplemen
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