No in all likelihood your analysis is not right. First of all DOS is hacking 1.0 . Any hacker with half a brain would use a distributed denial of service attack via a botnet in which case you would probably never get to the bottom of who is behind this. From your logs I can only glean that Europartners seem to have visited your site quite frequently.
What exactly is it that denies your service? You should be seeing something in the logs tying up your server’s resources?