TY - JOUR
T1 - Accurate Bus Occupancy Estimation for WLAN Probing Utilizing Probabilistic Models
AU - Mikkelsen, Lars Møller
AU - Madsen, Tatiana Kozlova
AU - Schwefel, Hans-Peter
PY - 2019
Y1 - 2019
N2 - This paper obtains an enhanced estimator of number of people on buses using probabilistic models and WLAN-based device counts. The improved estimator exploits probabilistic models of false positives and false negatives of a previously presented baseline estimator. False positives of the baseline estimator result from devices on the roadside outside the bus that fail to be filtered out by the used threshold approaches. False negatives may be caused by low probe emission frequency, message losses due to collisions of the WLAN transmissions, MAC address randomization, WLAN channel selection, and occur in particular when passengers stay on the bus only for short duration of time. The extensions of the baseline model by probabilistic models for false positives and false negatives enables to apply maximum likelihood estimation. Distribution parameters for false positives and false negatives are found from measurements. Field tests on buses in a Danish town are used to validate and quantify the gain of the enhanced estimator.
AB - This paper obtains an enhanced estimator of number of people on buses using probabilistic models and WLAN-based device counts. The improved estimator exploits probabilistic models of false positives and false negatives of a previously presented baseline estimator. False positives of the baseline estimator result from devices on the roadside outside the bus that fail to be filtered out by the used threshold approaches. False negatives may be caused by low probe emission frequency, message losses due to collisions of the WLAN transmissions, MAC address randomization, WLAN channel selection, and occur in particular when passengers stay on the bus only for short duration of time. The extensions of the baseline model by probabilistic models for false positives and false negatives enables to apply maximum likelihood estimation. Distribution parameters for false positives and false negatives are found from measurements. Field tests on buses in a Danish town are used to validate and quantify the gain of the enhanced estimator.
KW - Device counts
KW - WLAN probing
KW - bus occupancy
KW - Probabilstic Models
UR - https://www.inderscience.com/info/inarticle.php?artid=101240
U2 - 10.1504/IJSNET.2019.101240
DO - 10.1504/IJSNET.2019.101240
M3 - Journal article
SN - 1748-1279
VL - 30
SP - 231
EP - 241
JO - International Journal of Sensor Networks
JF - International Journal of Sensor Networks
IS - 4
ER -