The Journal Volume 3/1, June 2011 A peer-reviewed, open-access publication of the R Foundation for Statistical Computing Contents Editorial .................................................. 3 Contributed Research Articles testthat: Get Started with Testing ................................... 5 Content-Based Social Network Analysis of Mailing Lists ...................... 11 Rmetrics - timeDate Package ...................................... 19 The digitize Package: Extracting Numerical Data from Scatterplots ............... 25 Differential Evolution with DEoptim ................................. 27 rworldmap: A New R package for Mapping Global Data ..................... 35 Cryptographic Boolean Functions with R ............................... 44 Raster Images in R Graphics ...................................... 48 Probabilistic Weather Forecasting in R ................................. 55 Analyzing an Electronic Limit Order Book .............................. 64 Help Desk Giving a useR! Talk ............................................ 69 Tips for Presenting Your Work ..................................... 72 Book Reviews Forest Analytics with R (Use R) .................................... 75 News and Notes Conference Review: Third Meeting of Polish R Users, The Influenza Challenge ........ 76 Conference Review: Kickoff Workshop for Project MOSAIC .................... 78 Changes in R ............................................... 79 Changes on CRAN ............................................ 89 News from the Bioconductor Project .................................. 101 R Foundation News ........................................... 102