Table 3 Time window-event matrix of a user’s phone call log history
From: Evaluating smartphone-based dynamic security questions for fallback authentication: a field study
Window\day | Nov 14 | Nov 15 | \(\ldots\) | Dec 27 |
|---|---|---|---|---|
\(00:00-00:59\) | – | – | \(\ldots\) | \(\{Received call from-Jeff, 55 s\}\) |
\(01:00-01:59\) | – | – | \(\ldots\) | – |
\(\vdots\) | \(\vdots\) | \(\vdots\) | \(\vdots ~ \vdots ~ \vdots\) | \(\vdots\) |
\(14:00-14:59\) | \(\{Called-Alice, 55\, s\} , \{Called-Bob, 32\, s\}\) | \(\{Called-Bob, 89 \,s\}\) | \(\ldots\) | \(\{Called-Bob, 17\, s\}\) |
\(15:00-15:59\) | \(\{Called-John, 300\, s\}\) | \(\{Received call from-Jeff, 42\, s\}\) | \(\ldots\) | – |
\(16:00-16:59\) | \(\{Called-John, 14 \,s\}\) | \(\{Called-Bob, 20 \,s\}\) | \(\ldots\) | \(\{Called-Bob, 89 \,s\}\) |
\(17:00-17:59\) | \(\{Called-Bob, 27\, s\}\) | – | \(\ldots\) | – |
\(\vdots\) | \(\vdots\) | \(\vdots\) | \(\vdots ~ \vdots ~ \vdots\) | \(\vdots\) |
\(23:00-23:59\) | – | \(\{Received call-Bob, 14 \,s\}\) | \(\ldots\) | \(\{Called-Mike, 14 \,s\}\) |