1740 search results for "time series"

A time series classification contest

December 14, 2014
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A time series classification contest

Amongst today’s email was one from someone running a private competition to classify time series. Here are the essential details. The data are measurements from a medical diagnostic machine which takes 1 measurement every second, and after 32–1000 seconds, the time series must be classified into one of two classes. Some pre-classified training data is

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Twitter’s R package for detecting breakouts in time series

November 24, 2014
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Twitter’s R package for detecting breakouts in time series

With so many more devices and instruments connected to the "Internet of Things" these days, there's a whole lot more time series data available to analyze. But time series are typically quite noisy: how do you distinguish a short-term tick up or down from a true change in the underlying signal? To solve this problem, Twitter created the BreakoutDetection...

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Causality in Time Series – A look at 2 R packages (CausalImpact and Changepoint)

November 15, 2014
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My first blog post on Perceivant.comhttp://perceivant.com/causality-time-series-determining-impact-marketing-interventions/

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CausalImpact: A new open-source package for estimating causal effects in time series

September 10, 2014
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CausalImpact: A new open-source package for estimating causal effects in time series

How can we measure the number of additional clicks or sales that an AdWords campaign generated? How can we estimate the impact of a new feature on app downloads? How do we compare the effectiveness of publicity across countries?In principle, all of these questions can be answered through causal inference.In practice, estimating a causal effect...

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Specifying complicated groups of time series in hts

June 14, 2014
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With the latest version of the hts package for R, it is now possible to specify rather complicated grouping structures relatively easily. All aggregation structures can be represented as hierarchies or as cross-products of hierarchies. For example, a hierarchical time series may be based on geography: country, state, region, store. Often there is also a separate product hierarchy: product...

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Identifying periods of change in time series with GAMs

May 15, 2014
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Identifying periods of change in time series with GAMs

In previous posts (here and here) I looked at how generalized additive models (GAMs) can be used to model non-linear trends in time series data. In my previous post I extended the modelling approach to deal with seasonal data where we model both the within year (seasonal) and between year (trend) variation with separate smooth functions....

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Seasonal, or periodic, time series

March 20, 2014
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Seasonal, or periodic, time series

Monday, in our MAT8181 class, we’ve discussed seasonal unit roots from a practical perspective (the theory will be briefly mentioned in a few weeks, once we’ve seen multivariate models). Consider some time series , for instance traffic on French roads, > autoroute=read.table( + "http://freakonometrics.blog.free.fr/public/data/autoroute.csv", + header=TRUE,sep=";") > X=autoroute$a100 > T=1:length(X) > plot(T,X,type="l",xlim=c(0,120)) > reg=lm(X~T) > abline(reg,col="red") As discussed in a...

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Displaying time series, spatial, and space-time data with R is available for pre-order

Displaying time series, spatial, and space-time data with R is available for pre-order

Two years ago, motivated by a proposal from John Kimmel, Executive Editor at Chapman & Hall/CRC Press, I started working …Sigue leyendo →

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Fitting models to short time series

March 3, 2014
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Fitting models to short time series

Following my post on fitting models to long time series, I thought I’d tackle the opposite problem, which is more common in business environments. I often get asked how few data points can be used to fit a time series model. As with almost all sample size questions, there is no easy answer. It depends on the number of model parameters...

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More time series data online

February 27, 2014
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Earlier this week I had coffee with Ben Fulcher who told me about his online collection comprising about 30,000 time series, mostly medical series such as ECG measurements, meteorological series, birdsong, etc. There are some finance series, but not ma...

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