Be careful when using abbreviations in you presentation. Make sure that when you use an abbreviation without explaining where it stands for that your entire audience knows what you are talking about. You audience will be quickly lost when you give them a presentation about GDPR and you explain the role of an DPO in regards to the DPIA.
Make sure your audience is familiar with the abbreviation, ask to make certain and also show the abbreviation and what it means on a presentation slide. If you are not 100% certain that it is understood, then simply don’t use an abbreviation.