The average travelling speed increases in a nontrivial manner with the travel distance. This leads to scaling-like relations on quite extended spatial scales, for all mobility modes taken together and also for a given mobility mode in part. We offer a wide range of experimental results, investigating and quantifying this universal effect and its measurable causes. The increasing travelling spee...

BACKGROUND Long distance is a leading environmental barrier to walking to school and requires long-term, multilevel interventions. Meanwhile, childhood obesity remains highly prevalent, calling for more immediate solutions. PURPOSE The purpose of this study was to examine attitudinal and environmental correlates of walking to the elementary school, controlling for distance. METHODS Using pa...

Travel Mode Identification with Smartphone Sensors by Xing Su Advisor: Hanghang Tong Personal trips in a modern urban society typically involve multiple travel modes. Recognizing a traveller’s transportation mode is not only critical to personal context-awareness in related applications, but also essential to urban traffic operations, transportation planning, and facility design. While the stat...

Mode travel time estimation in the presence of internal waves (IWs) is a challenging problem. IWs perturb the sound speed, which results in travel time wander and mode scattering. A standard approach to travel time estimation is to pulse compress the broadband signal, pick the peak of the compressed time series, and average the peak time over multiple receptions to reduce variance. The peak-pic...

At long ranges, broadband receptions consist of early ray-like arrivals and a finale that is best described in terms of the low order modes. The energetic low mode signals are more strongly affected by internal wave scattering than the ray arrivals. By focusing on the low modes, this project seeks to develop a better understanding of internal wave effects. The first objective of this project is...