publications - My supervisor plagiarised my bachelor thesis: what can I do about it?

In July 2012 I submitted a bachelor's thesis on a machine learning topic. I designed an algorithm that I developed in Java.

Now I have found a publication (September 2012) by my supervisor with all the results of my thesis, including images, with only a thanks at the end for the "Java implementations", but all of the results and the designed algorithm were taken from my thesis. The supervisor has not added anything to what I had already written in my thesis.

For me she had to add my name as a co-author of publications. Of course the supervisor helped me in the writing of the thesis but having only revived my job in publishing, then I was expecting my name as a co-author because she has not added anything new.

What recourse do I have?

Edit1:
One problem is that my thesis, about 140 page, was written in Italian and the pubblication was in English. For this reason I suppose it's hard to write to the Journal to show him my thesis. In addition, my thesis is not published online on any official channel.

The project and the thesis was made by me and one other student with the constant help of her (supervisor). But on the publication the name is of Supervisor, Co-supervisor and one more people (i suppose this people have translated 140 italian page in 5-6 english page) but why not me?

In add now I'm in other city, in other university and now i have no bridge between my supervisor.

If i have no more contact (only an email) with supervisor is there any way to write to the person who published that? and how can I prove that content is that of my thesis?

Answer

Unfortunately, your story does not seem implausible to me at all. Here in central Europe, some computer science departments seem to have a very lax mentality when it comes to acknowledging research contributions coming from undergrads or non-research master students. In some places, this thinking seems to be so ingrained that even otherwise honest and fair researchers do not even consider putting the name of undergrads on papers despite their work making up a significant part of the paper's research contribution (something that the same faculty would never do and, in fact, consider highly unethical, if the student was a PhD or a master student on a research track). I guess part of the problem is that around here, the majority of students heading for an industry career (which is almost everybody at many large universities) does not care one way or another, so nobody really complains about this practice (which, of course, does not make it ok).

(the following is written under the assumption that what you wrote is actually correct - clearly, my advise is terrible if you vastly overstated your contributions)

If i have no more contact (only an email) with supervisor is there any way to write to the person who published that? and how can I prove that content is that of my thesis?

You should definitely get in touch with your supervisor. Keep the mail friendly, but do make clear that you are not ok with how this has went down. If (s)he is one of those that simply did not consider whether you should actually also be a co-author of this paper, there is a good chance that (s)he is in fact pretty embarrassed by the incident. Presumably, the first thing that the faculty will explain that this "is just the way it works around here". Don't accept this excuse (even though it might be factually true). Be aware that you are in the right here, and that you raising your valid concerns to the conference organisers will at least be really embarrassing for the faculty (and, as stated on this website once, reputation is the currency of science), so you do have some leverage.

Essentially, I think the onus is on the faculty to come up with a solution here. It is not like you need to think of a way how this can be resolved sufficiently. Maybe your supervisor will think of a solution for your issue that is acceptable for you. As a last resort, you can contact the organisers of the conference, as stated by just-learning, and give them the information that you also gave us above (now deleted). Be aware that you will likely gain little by this move, though - presumably, either nothing will happen or the paper will be removed from the proceedings. In any case, the reputation of the authors will likely be tarnished quite a bit by this incident, and, as stated in another answer, you will have certainly burned all bridges with this group of people.