Qn regarding DeJong's Fn and results

[kc_@ejazzmail.com]

Hi there

    I've come across the following which I hope to seek clarification:

De Jong's Approach can be measured in terms of
1) on-line performance
2)  off-line performance

Applying these to his Test Functions, the results of De Jong's Studies
show

1)    larger population sizes
        lead to better offline performance
        result in poorer initial online performance

2)    smaller populations exhibit better initial online performance


However, I'm unclear of the meaning of on-line & off-line performance.
Is there a simpler explanation to these terms and their meaning when
used to describe DeJong's Functions?

    TIA for all help..

ken