"Is not the truth the truth?": Analyzing the Impact of User Validations for Bus In/Out Detection in Smartphone-based Surveys

Abstract

Passenger flow allows the study of users' behavior through the public network and assists in designing new facilities and services. This flow is observed through interactions between passengers and infrastructure. For this task, Bluetooth technology and smartphones represent the ideal solution. The latter component allows users' identification, authentication, and billing, while the former allows short-range implicit interactions, device-to-device. To assess the potential of such a use case, we need to verify how robust Bluetooth signal and related machine learning (ML) classifiers are against the noise of realistic contexts. Therefore, we model binary passenger states with respect to a public vehicle, where one can either be-in or be-out (BIBO). The BIBO label identifies a fundamental building block of continuously-valued passenger flow. This paper describes the Human-Computer interaction experimental setting in a semi-controlled environment, which involves: two autonomous vehicles operating on two routes, serving three bus stops and eighteen users, as well as a proprietary smartphone-Bluetooth sensing platform. The resulting dataset includes multiple sensors' measurements of the same event and two ground-truth levels, the first being validation by participants, the second by three video-cameras surveilling buses and track. We performed a Monte-Carlo simulation of labels-flip to emulate human errors in the labeling process, as is known to happen in smartphone surveys; next we used such flipped labels for supervised training of ML classifiers. The impact of errors on model performance bias can be large. Results show ML tolerance to label flips caused by human or machine errors up to 30%.

arXiv comment22 pages, 11 figures, 4 tables, 3 algorithms

References in corpus (9)

• Identifying Mislabeled Training Data
• Training Convolutional Networks with Noisy Labels
• Inferring transportation modes from GPS trajectories using a convolutional neural network
• Deep Learning is Robust to Massive Label Noise
• Noise Tolerance under Risk Minimization
• Beyond Synthetic Noise: Deep Learning on Controlled Noisy Labels
• Peer Loss Functions: Learning from Noisy Labels without Knowing Noise Rates
• Softwarization, Virtualization, & Machine Learning For Intelligent & Effective V2X Communications
• Mining User Behaviour from Smartphone data: a literature review

Cited by in corpus (1)

• Large Scale Passenger Detection with Smartphone/Bus Implicit Interaction and Multisensory Unsupervised Cause-effect Learning