Sending M.Sc. dissertation to a big conference
Typically a dissertation is not considered to be a peer reviewed publication.  This means that the material in it can be extracted and turned into conference or journal publications.  In some fields, this is a typical practice after completing a dissertation, where in others it goes the other way (the dissertation is assembled from peer-reviewed papers).

You cannot, however, just submit your thesis directly as is.  A dissertation is generally much longer than conference or journal papers.  A dissertation typically also has much more freedom in style, and does not have to be targeted at the biases of a particular community.  Thus, to make a credible conference submission, you will need to compress or extract a nugget of contribution of an appropriate size, and may also need to tailor its focus and language to better match that of the conference where it is being submitted.