Yes, it's possible for attacks of that kind to succeed. No, it doesn't seem to be currently practical. As of around 2011 (3 years after this paper was published) even the NSA was reporting difficulty with deanonymizing Tor users.
We will never be able to deanonymize all Tor users all the time
With manual analysis we can deanonymize a very small fraction of Tor users, however, no success de-anonymizing a user [on demand].
This is already covered in the Tor Project FAQ.
... it is possible for an observer who can view both you and either the destination website or your Tor exit node to correlate timings of your traffic as it enters the Tor network and also as it exits. Tor does not defend against such a threat model.