1825 search results for "time series"

Second NYC R classes(announcement and teaching experience)

January 20, 2014
By
Second NYC R classes(announcement and teaching experience)

(The photo was from our first offering of R classes) We are going to offer our Data Science by R (beginner level) course again in February. The goal of this class is to get students to a point where they are self-sufficient in R, are proficient at analyzing data and can take these skills back to their full-time jobs....

Read more »

What is volatility?

January 19, 2014
By
What is volatility?

Some facts and some speculation. Definition Volatility is the annualized standard deviation of returns — it is often expressed in percent. A volatility of 20 means that there is about a one-third probability that an asset’s price a year from now will have fallen or risen by more than 20% from its present value. In … Continue reading...

Read more »

Fast-track publishing using knitr: table mania (part IV)

January 15, 2014
By
Fast-track publishing using knitr: table mania (part IV)

Fast-track publishing using knitr is a short series on how I use knitr to speedup publishing in my research. While illustrations (previous post) are optional, tables are not, and this fourth article is therefore devoted to tables. Tables through knitr is probably one of the most powerful fast-track publishing tools, in this article I will show (1) how...

Read more »

Butterworth filter overshoot

January 15, 2014
By
Butterworth filter overshoot

Introduction Butterworth filters with order other than 1 have an overshoot phenomenon that can be problematic in some cases. For example, if smoothing is used on an estimate of kinetic energy, overshoots might yield negative values that are nonphysical. This post simply illustrates this with made-up data that the reader can experiment with. Methods First, create and plot...

Read more »

Smoothing CTD profiles

January 11, 2014
By
Smoothing CTD profiles

Introduction Smoothing hydrographic profiles with conventional time-series methods is problematic for two reasons: (a) the data are commonly not equi-spaced in depth and (b) the data seldom lack trends in depth. The issues and their solutions are illustrated without much discussion here. The first step in making the graph shown above is to load the oce library and...

Read more »

Summarising multivariate palaeoenvironmental data

January 9, 2014
By
Summarising multivariate palaeoenvironmental data

The horseshoe effect is a well known and discussed issue with principal component analysis (PCA) (e.g. Goodall 1954; Swan 1970; Noy-Meir & Austin 1970). Similar geometric artefacts also affect correspondence analysis (CA). In part 1 of this series I looked at the implications of these “artefacts” for the recovery of temporal or single dominant gradients from multivariate palaeoecological data....

Read more »

Fast-track publishing using knitr: exporting images for sharing and press (part III)

January 7, 2014
By
Fast-track publishing using knitr: exporting images for sharing and press (part III)

(This article was first published on G-Forge » R, and kindly contributed to R-bloggers) Images can be a powerful medium if used right. The image is CC by alemdag. Fast-track publishing using knitr is a short series on how I use knitr to speedup publishing in my research. This is the third article in the series devoted to plots....

Read more »

analyze the national immunization survey (nis) with r

January 6, 2014
By

for twenty years now, the centers for disease control and prevention (cdc) has been random-digit-dialing american households to ask parents which vaccinations their little tykes have received.  and since vaccination history might not be at the for...

Read more »

Cran2deb4ubuntu: An Update for 2014

January 5, 2014
By

I have been a little quiet on the update front for the past few months, so I thought I would give a quick update as 2014 begins. Between increased responsibilities at work (pseudo-department chair) and some family health issues, work on cran2deb4ubunt...

Read more »

Fast-track publishing using knitr: intro (part I)

December 30, 2013
By
Fast-track publishing using knitr: intro (part I)

Fast-track publishing using knitr is a short series on how I use knitr to get my articles faster published. By fast-track publishing I mean eliminating as many of the obstacles as possible during the manuscript phase, and not the fast-track some journals offer. In this first introductory article I will try to (1) define the main groups of...

Read more »