Well.. as a student, I have had to write these things...

I think Roger said it nicely - Preface the abstract with: [In this study]...

Below is a link on how to write an abstract.. there are methods for this stuff... look at the informative abstract...
An INFORMATIVE abstract summarizes the entire report and gives the reader an overview of the facts that will be laid out in detail in the paper itself.

Canie

• How to write an abstract