Today I finally got around to use Automator, and make one of the command line scripts I have been running for ages a little easier to use.

The problem I have been trying to solve is the fact that the PDF files that a Mac creates are normally of very high quality and hence large. If you just want to send someone a document for reading on screen, a much smaller PDF file would do. The open source package “ghostscript” has a tool called ps2pdf that can be (ab)used to adjust the size of components for PDF files. I installed this in /opt/local/bin using the “macports” software.

To make it possible to do the PDF-shrinking from the Finder, I started automator, and made a new “Service”. I instructed it to use PDF files, and only in the Finder. In the workflow, I added a “run shell script” step. The system passes the files as arguments to this script.

The contents of the script are:

export PATH=$PATH:/opt/local/bin
for f in "$@"
do
    echo "$f"
    d=`dirname "$f"`
    cd "$d"
    b=`basename "$f"`
    ps2pdf -dPDFSETTINGS=/ebook "$b"
    #      Choose /screen for even smaller PDF, or 
    #      /printer /prepress or /default for successively larger
    if [ -f "$b".pdf ]; then
        mv "$b" "$b".old
        mv "$b".pdf "$b"
    else 
        echo "Apparently conversion failed"
    fi
done

I saved this as the service named “Small PDF”, and Done!

And using it is even easier:

I was reading some news when I noticed a mathematical curiosity. The article on a physics result mentioned a chance of “one in ten to the minus 7”. Of course this is a mistake: a small chance is either one in ten to the 7” or “ten to the minus 7”. The combination of “one in” and “minus” is nonsense. Interesting enough, this mistake is really common….

My native language is Dutch. My wife’s is French. We both speak each other’s language fluently. But we originally met each other in Germany, and have always been speaking English together.

When we got our son, we ignored all warnings around us about confusing a child, and built a tri-lingual household. I still speak English with my wife, but we both speak to our son in our own native tongue. We never used English as a secret language and always explained what we were speaking about whenever he asked.

Growing up, he has had little difficulty making progress in French as well as Dutch. This is a contrast with stories we hear from bi-lingual families where the parents together speak one of the two languages they are teaching their kids (“why do I have to speak French to my mother if my parents together speak Dutch too?”). And as a bonus, our son became fluent in English as well.

If books mention “breaking silence” less frequently, does that mean that we have more silence now because it is no longer broken? Or does it mean that we do not have silence any more, so that it can no longer be broken? Is it a coincidence that the phrase seriously decreases in frequency after the invention of the mass produced car?

Thinking about Poisson statistics I was wondering how much use a clock would be that would count the seconds with counting statistics or Poisson statistics. That is: it has the irregularity of radio-active decay. Some people put their watch a few minutes ahead of the true time to make sure that they are never too late, but the problem is that they can start counting on that after a while. A true random clock might be unreliable enough that you would need to always stay carefully ahead….

Counting statistics make a variance that is equal to the value. Therefore, the standard uncertainty is the square root of the value.

Lets see what that means: our watch, after a minute, has an uncertainty of about 8 seconds. After an hour, a minute. After a day, five minutes. After a month, half an hour. And after a year, the uncertainty would be a little over one and a half hours.

To be 95% sure to be in time for an appointment a day after synchronizing your Poisson watch, you need to arrive 10 minutes ahead of your watch. And there is a 5% chance you will be 20 minutes early….. 

No, I’ll stick with just being in time.

Still, I think it would be kind of cool to have a watch that goes “tick tick        tick  tick       tick tick titick    tick……”