A Real-Time Location-Based Services System Using WiFi Fingerprinting Algorithm for Safety Risk Assessment of Workers in Tunnels

Table 1

The three-main-factor matrix.

Risk probability (L)		Risk frequency (E)		Factor weight (C)
Score	Probability of an accident or dangerous occurrence	Score	Probability of an accident or dangerous occurrence	Score	Probability consequence
10	Absolutely possible	10	Always	100	Tragedy	Many death
6	Possible	6	Everyday	40	Very severe	Some death
3	Possible, but not often	3	Every week or occasionally	15	Severe	Loss of life or injured seriously
1	Almost not possible	2	Every month	7	Serious	Injured
0.5	Possible rarely	1	Every year	3	Normal	Injured slightly and can be recovered
0.2	Hardly possible	0.5	Hardly happen	1	Concern	Not healthy basically
0.1	Impossible in realty