[paper] Expand first paragraph

[lrnv]

The first paragraph of the statement of needs is very well written and precise in its wording. However, it is a bit short for persons that are not accointed to the field to understand what is happening.

Between the two sentences, you might add a third one starting by "For exemple, ..." to give an exemple of a interesting sensitivity and why it is so.

[ahudde]

Dear, @lrnv, what do you think of this explanation?

[lrnv]

Perfect !