56,635 research outputs found
Transductive-Inductive Cluster Approximation Via Multivariate Chebyshev Inequality
Approximating adequate number of clusters in multidimensional data is an open
area of research, given a level of compromise made on the quality of acceptable
results. The manuscript addresses the issue by formulating a transductive
inductive learning algorithm which uses multivariate Chebyshev inequality.
Considering clustering problem in imaging, theoretical proofs for a particular
level of compromise are derived to show the convergence of the reconstruction
error to a finite value with increasing (a) number of unseen examples and (b)
the number of clusters, respectively. Upper bounds for these error rates are
also proved. Non-parametric estimates of these error from a random sample of
sequences empirically point to a stable number of clusters. Lastly, the
generalization of algorithm can be applied to multidimensional data sets from
different fields.Comment: 16 pages, 5 figure
What makes them so good? The constructs used by coaches to identify coaching prowess
The criterion which coaches use to judge their peers are extremely pertinent to the study and enhancement of coach development. The aim of this two-part study was to offer insight into how a sample of British sub-elite coaches judged coaching prowess and perceived the nature of the expertise possessed (or perceived to be possessed) by their own self-selected role model coaches. Data from field notes and transcribed conversations with 143 coaches, drawn from over 15 years of conversations, were interpreted following an inductive analysis. Subsequently, follow up focus group interviews involving 15 level three coaches in a range of sports were used to augment and, if appropriate, question these data. Results yielded an array of personal characteristics, which participants used to describe “what” role model coaches did or were like, as opposed to professional or behavioural characteristics that explained “how” they worked. Consideration of these findings offers some areas for immediate exploitation, alongside some key concerns which must be addressed if the trend for social learning based coach development initiatives are to have optimum benefit
A Very Brief Introduction to Machine Learning With Applications to Communication Systems
Given the unprecedented availability of data and computing resources, there
is widespread renewed interest in applying data-driven machine learning methods
to problems for which the development of conventional engineering solutions is
challenged by modelling or algorithmic deficiencies. This tutorial-style paper
starts by addressing the questions of why and when such techniques can be
useful. It then provides a high-level introduction to the basics of supervised
and unsupervised learning. For both supervised and unsupervised learning,
exemplifying applications to communication networks are discussed by
distinguishing tasks carried out at the edge and at the cloud segments of the
network at different layers of the protocol stack
Probabilities and health risks: a qualitative approach
Health risks, defined in terms of the probability that an individual will suffer a particular type of adverse health event within a given time period, can be understood as referencing either natural entities or complex patterns of belief which incorporate the observer's values and knowledge, the position adopted in the present paper. The subjectivity inherent in judgements about adversity and time frames can be easily recognised, but social scientists have tended to accept uncritically the objectivity of probability. Most commonly in health risk analysis, the term probability refers to rates established by induction, and so requires the definition of a numerator and denominator. Depending upon their specification, many probabilities may be reasonably postulated for the same event, and individuals may change their risks by deciding to seek or avoid information. These apparent absurdities can be understood if probability is conceptualised as the projection of expectation onto the external world. Probabilities based on induction from observed frequencies provide glimpses of the future at the price of acceptance of the simplifying heuristic that statistics derived from aggregate groups can be validly attributed to individuals within them. The paper illustrates four implications of this conceptualisation of probability with qualitative data from a variety of sources, particularly a study of genetic counselling for pregnant women in a U.K. hospital. Firstly, the official selection of a specific probability heuristic reflects organisational constraints and values as well as predictive optimisation. Secondly, professionals and service users must work to maintain the facticity of an established heuristic in the face of alternatives. Thirdly, individuals, both lay and professional, manage probabilistic information in ways which support their strategic objectives. Fourthly, predictively sub-optimum schema, for example the idea of AIDS as a gay plague, may be selected because they match prevailing social value systems
Efficient algorithms for decision tree cross-validation
Cross-validation is a useful and generally applicable technique often
employed in machine learning, including decision tree induction. An important
disadvantage of straightforward implementation of the technique is its
computational overhead. In this paper we show that, for decision trees, the
computational overhead of cross-validation can be reduced significantly by
integrating the cross-validation with the normal decision tree induction
process. We discuss how existing decision tree algorithms can be adapted to
this aim, and provide an analysis of the speedups these adaptations may yield.
The analysis is supported by experimental results.Comment: 9 pages, 6 figures.
http://www.cs.kuleuven.ac.be/cgi-bin-dtai/publ_info.pl?id=3478
Conformal Prediction: a Unified Review of Theory and New Challenges
In this work we provide a review of basic ideas and novel developments about
Conformal Prediction -- an innovative distribution-free, non-parametric
forecasting method, based on minimal assumptions -- that is able to yield in a
very straightforward way predictions sets that are valid in a statistical sense
also in in the finite sample case. The in-depth discussion provided in the
paper covers the theoretical underpinnings of Conformal Prediction, and then
proceeds to list the more advanced developments and adaptations of the original
idea.Comment: arXiv admin note: text overlap with arXiv:0706.3188,
arXiv:1604.04173, arXiv:1709.06233, arXiv:1203.5422 by other author
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