The R Journal Volume 4/1, June 2012

The Journal Volume 4/1, June 2012 A peer-reviewed, open-access publication of the R Foundation for Statistical Computing Contents Editorial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Contributed Research Articles Analysing Seasonal Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 MARSS: Multivariate Autoregressive State-space Models for Analyzing Time-series Data . . 11 openair – Data Analysis Tools for the Air Quality Community . . . . . . . . . . . . . . . . . . 20 Foreign Library Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Vdgraph: A Package for Creating Variance Dispersion Graphs . . . . . . . . . . . . . . . . . . 41 xgrid and R: Parallel Distributed Processing Using Heterogeneous Groups of Apple Com- puters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 maxent: An R Package for Low-memory Multinomial Logistic Regression with Support for Semi-automated Text Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Sumo: An Authenticating Web Application with an Embedded R Session . . . . . . . . . . . 60 From the Core Who Did What? The Roles of R Package Authors and How to Refer to Them . . . . . . . . . 64 News and Notes Changes in R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 on CRAN . . .