The Key to Success
Usually, the most important element in achieving a takedown is locating the agent for service of the DMCA notice. Here's a list of designated agents. In addition to the designated agent (or if you can't find the agent) check the site for other forms of email (or other addresses) for the website owner. Sometimes, you can find it on a "Contact Us" link and often it is simply, "firstname.lastname@example.org." Many sites that post files or post documents have a special mailbox for dealng with infringements -- often that's "email@example.com" or "firstname.lastname@example.org." If there is no designated agent, and no email address for contacting the owners at the site (not a good sign), search for the owner using the database at Whois.net. If your search results in a "proxy" administrator -- a company that serves as administrator and hides the name and contact info for the owner, that's also not a good sign. Once you locate an agent, or email or mailing address for the administrator of the site, you should prepare and send a DMCA takedown notice. Here's an example. (One site has even automated the process.)
What if the Site Refuses to Take it Down.
The approach described above is usually effective -- at least it often works for the Dear Rich Staff. However, if the person who posted the thesis refuses to take it down (or they respond with the countermeasures we discussed in this entry), you will need to proceed with a copyright registration (you can expedite it) and file a lawsuit. Unless you are independently wealthy, that could be cost-prohibitive. If the website owner has deep pockets and you can demonstrate financial damages, perhaps you can find a lawyer who will handle it on a contingency.