In a project of developing PPNR balance projection models, I tried to use the Phillips-Ouliaris (PO) test to investigate the cointegration between the historical balance and a set of macro-economic variables and noticed that implementation routines of PO test in various R packages, e.g. urca and tseries, would give different results. After reading through the original paper “Asymptotic Properties of Residual Based Tests for Co-Integration” by P. Phillips again, I started realizing that the po.test() function in the tseries package and the ca.po() function in the urca package are implementing different types of Phillips-Ouliaris cointegration tests. In other words, the so-called “Phillips-Ouliaris Cointegration test” is not A statistical test but a set of statistical tests with different assumptions, formulations, critical values, and implications.
An R Shiny app to recognize flower species
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Why do sociologists (and bloggers) focus on the negative? 5 possible explanations. (A post in the style of Fabio Rojas)
Fabio Rojas asks why the academic field of sociology seems so focused on the negative. As he puts it, why doesn’t the semester begin with the statement, “Hi, everyone, this is soc 101, the scientific study of society. In this class, I’ll tell you about how American society is moving in some great directions as well as some lingering problems”?
Top Stories, Dec 10-16: Why You Shouldn’t be a Data Science Generalist; Machine Learning & AI Main Developments in 2018 and Key Trends for 2019
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Contingency Tables in R
Document worth reading: “Coupled Ensembles of Neural Networks”
We investigate in this paper the architecture of deep convolutional networks. Building on existing state of the art models, we propose a reconfiguration of the model parameters into several parallel branches at the global network level, with each branch being a standalone CNN. We show that this arrangement is an efficient way to significantly reduce the number of parameters without losing performance or to significantly improve the performance with the same level of performance. The use of branches brings an additional form of regularization. In addition to the split into parallel branches, we propose a tighter coupling of these branches by placing the ‘fuse (averaging) layer’ before the Log-Likelihood and SoftMax layers during training. This gives another significant performance improvement, the tighter coupling favouring the learning of better representations, even at the level of the individual branches. We refer to this branched architecture as ‘coupled ensembles’. The approach is very generic and can be applied with almost any DCNN architecture. With coupled ensembles of DenseNet-BC and parameter budget of 25M, we obtain error rates of 2.92%, 15.68% and 1.50% respectively on CIFAR-10, CIFAR-100 and SVHN tasks. For the same budget, DenseNet-BC has error rate of 3.46%, 17.18%, and 1.8% respectively. With ensembles of coupled ensembles, of DenseNet-BC networks, with 50M total parameters, we obtain error rates of 2.72%, 15.13% and 1.42% respectively on these tasks. Coupled Ensembles of Neural Networks
2018-13 Rendering HTML Content in R Graphics
This report describes several R packages that allow HTML content to be rendered as part of an R plot. The core package is called ‘layoutEngine’, but that package requires a “backend” package to perform HTML layout calculations. Three example backends are demonstrated: ‘layoutEngineCSSBox’, ‘layoutEnginePhantomJS’, and ‘layoutEngineDOM’. We also introduce two new font packages, ‘gyre’ and ‘courier’.
R Packages worth a look
A Parser for ‘ArchieML’ (rchie)Parses the ‘ArchieML’ format from the New York Times http://archieml.org. Also provides ut …