Archive for category Uncategorized

Updating local Git repository to most recent version

Posted by on Tuesday, 19 April, 2011

So I use some software from a Git repository. The idea is simple, when the developers update it I simply have to update the local repository to the recent HEAD in the master branch and I have the up-to-date stuff to link against.

But how to do this?

$ git pull
Should do the trick when executed in the directory where the .git is located (find this with ls -lAh to show hidden files).

You may get an error like:

5764cf9..5d8cc2a master -> origin/master
Updating 5764cf9..5d8cc2a
error: Your local changes to '.oppbuildspec' would be overwritten by merge. Aborting.
Please, commit your changes or stash them before you can merge.

This can be easily fixed:
$ git stash save "updating to head from repo"
And now we can proceed with the git pull command.

Thanks to

A Unit Disc propagation model for MiXiM

Posted by on Thursday, 7 April, 2011

MiXiM’s analogueModels provide some neat opportunities to make propagation models of great detail and complexity. But what if you want to use the simplest of all, the Unit Disc (Graph) model? You simply state a ‘communication’ range and within that range all nodes receive the message, outside they don’t. Simple as that. We did the work for you. Read the rest of this entry »


Posted by on Thursday, 24 March, 2011

Zelf werk ik al een tijdje in een autogarage, waar ik ooit begonnen ben met opruimen en de vloer vegen, en ondertussen allerhande reparaties verricht. In die zes en en half jaar heb ik toch wel van alles opgepikt, maar wat me elke keer nog weer blijft verbazen zijn de woorden “Die motoren zijn niet kapot te krijgen”. Niet omdat de zin op zichzelf zo vreemd is, maar omdat het daarbij altijd over een oud type auto gaat! Nieuwe auto’s worden niet meer gemaakt met het label ‘niet kapot te krijgen’. Sterker nog: als je een nieuwe auto koopt ben je veel meer kwijt aan onderhoud dan wanneer je een oud barrel gaat opknappen. Read the rest of this entry »

OMNeT++ order of iteration variables

Posted by on Thursday, 10 March, 2011

Say you are running a set of (rather lengthy) experiments for several iteration
variables (numHosts and packetsPerSecond for instance) and want to have several
replications per scenario for statistical significance (which is usually a nice idea).

Now, you want to get a quick indication how the simulation is going, and have statistical significance increase as the number of runs increases. How to do this?
Read the rest of this entry »

Attacks by “Anonymous” WikiLeaks proponents not anonymous

Posted by on Friday, 10 December, 2010

For a number of days the websites of MasterCard, Visa, PayPal and others are attacked by a group of WikiLeaks supporters (hacktivist). Although the group calls itself “Anonymous”, researchers at the DACS group of the University of Twente (UT), the Netherlands, discovered that these hacktivists are easy traceable, and therefore anything but anonymous. The LOIC (Low Orbit Ion Cannon) software, which is used by the hacktivists, was analyzed by UT researchers, who concluded that the attacks generated by this tool are relatively simple and unveil the identity of the attacker. If hacktivists use this tool directly from their own machines, instead of via anonymization networks such as Tor, the Internet address of the attacker is included in every Internet message being transmitted. In the tools no sophisticated techniques are used, such as IP-spoofing, in which the source address of others is used, or reflected attacks, in which attacks go via third party systems. The current attack technique can therefore be compared to overwhelming someone with letters, but putting your address at the back of the envelop. In addition, hacktivists may not be aware that international data retention laws require that commercial Internet providers store data regarding Internet usage for at least 6 months. This means that hacktivists can still be traced easily after the attacks are over.

A complete report about that can be downloaded from this link.