Posts tagged 'technical' – Page 3


Embedding fonts in PDF-files

A while back I wrote a course-reader in Writer on Ubuntu. When I submitted it for printing, it turned out that not all fonts were embedded in the document, which led to various printing- and layout-problems. Here's some advice on how to create PDFs that are suitable for …


Recompressing (optimising) PDF files

There are at least three ways to do this in Ubuntu. You will need the packages ghostscript (for all methods, but installed by default) and pdftk (for method 2), and optionally a Java Runtime Environment (for method 3).

Method 1: ps2pdf

The ps2pdf script that comes with Ghostscript is meant …


Batch search & replace in PDF files

The other day I found out I had misspelled a word in a whole batch of automatically generated PDF files. Regenerating all of them would be a lot of work, as the PDF files were plots created using perl/PDL, gnuplot and epstopdf (available in texlive-extra-utils), and the input data …


Installing and using fonts in Ubuntu

Older versions of Ubuntu (before 8.04) used to have a built-in font-manager that could be reached by browsing font:/// in the file-manager. However, when Gnome upgraded to their new gvfs in 2008, their font manager and viewer both stopped working. In current Ubuntu-versions, at least the built-in font viewer …


Low-cost USB temperature logging

UPDATE (2015):

These days, if you want to measure temperature, humidity and other environmental variables cheaply, there's no need to mess around with unreliable USB-sensors. It's more reliable (and not that much more difficult) to simply use a Raspberry Pi or an Arduino and connect sensors directly using I2C, SPI …


How to merge video files

How to merge/join/combine/concatenate multiple video files

Say you have a collection of short video clips made with a telephone or digital camera, and you want to join them into a single video file. How can you do this without having to re-encode everything?

In Ubuntu Linux:

What …


Extracting TIFF pictures from MS Word for Mac documents

Recently I tried to open several old MS Word files created on a Macintosh in on my Ubuntu machine. The text part of the documents got converted just fine by Writer, but the images became rather messed up. Anything that had been imported as a bitmap …


Data Clustering

I've written a fast perl/PDL implementation of UPGMA data clustering for very large datasets. The problem is that existing clustering packages have difficulty handling datasets with more than a few thousand data points. Especially the distance matrices tend to become a problem. For example, clustering the outcome of a …


Ubuntu Repository


The original repository was getting a bit outdated. It was trailing a few Ubuntu-releases behind and only had i386-builds. You can still use it for Hardy or manually download packages (see below) for installation on newer releases, but I'm no longer going to maintain the old repository …


Hardware 3D acceleration on an ATI Radeon 9600 mobile

UPDATE (2010-08-25): This article describes how to configure Ubuntu 8.04 LTS (Hardy Heron) for stable 3D-acceleration and desktop-effects with ATI R300 series (Radeon Mobility 9600 and similar) GPUs. On recent Ubuntu versions (such as 10.04 LTS) this should work out of the box, and making modifications to xorg …