A High-Precision Fatigue Detecting Method for Air Traffic Controllers Based on Revised Fractal Dimension Feature

Table 3

Numbering rules of the speech database constructed in this study.

Number position	Expression	Explanation
1	Control categories	R: area control, A: approach control, T: tower control
2	ATC’s rank	5: Level 5, 4: Level 4, 3: Level 3, 2: Level 2, 1: Level 1, 0: Trainee
3–10	Time (UTC）	Numbers 3 to 6: starting time of work, Numbers 7 to 10: ending time of work
11	Sex	F: female, M: male
12-13	Age	Arabic number representation of real age
14-15	Order	Nn:N is a digital indicator and n is an Arabic numeral, indicating the nth instruction issued by a ATC during working
16-17	Status	14th and 15th: voice command; 1: error, 2: ambiguity, 3: hesitation or pause, 4: fatigue

Note. (1) The Arabic numerals immediately following N are treated as a numbering number regardless of the number of digits. (2) Number position 14-15 indicates the speech state. When the speech is normal, there number position 16 is vacant.