Speech security outside meeting rooms
Regular paper
Acoustic Research Unit, School of Architecture
Tuesday 2 june, 2015, 15:00 - 15:20
0.9 Athens (118)
Abstract:
A new approach to provide speech security outside meeting rooms is described
where a covert listener might attempt to extract confidential information.
Decision-based experiments are used to establish a relationship between an
objective measurement of the Speech Transmission Index (STI) and a subjective
assessment relating to the threshold of information leakage. This threshold is
defined for a specific percentage of English words that are identifiable with
a maximum safe vocal effort (e.g., “normal” speech) used by the meeting
participants. The results demonstrate that it is possible to quantify an
offset that links STI with a specific threshold of information leakage which
describes the percentage of words identified. The offsets for male talkers are
shown to be approximately 10 dB larger than for female talkers. Hence for
speech security it is possible to determine offsets for the threshold of
information leakage using male talkers as the “worst case scenario.” To define
a suitable threshold of information leakage, the results show that a robust
definition can be based upon 1%, 2%, or 5% of words identified. For these
percentages, results are presented for offset values corresponding to
different STI values in a range from 0.1 to 0.3.