Travel Behavior

A Cyber-physical Systems Approach to the Design of Vehicle Safety Networks

Fallah, Yaser P.
Raja Sengupta
2012

The concept of cooperative vehicle safety (CVS) is based on cooperation of vehicles in achieving real-time situation awareness for the purpose of safer (and possibly autonomous) driving. Since CVS is a safety system, situation awareness has to be real-time with high accuracy. Cooperation in the context of CVS is achieved through vehicular networks that are tuned to the purpose of vehicle state tracking in a neighborhood around each vehicle. In this paper, we describe different methodologies in approaching the design of CVS, and propose a systematic Cyber-Physical Systems approach to the...

Evaluation of Real-Time Freeway End-of-Queue Alerting System to Promote Driver Situational Awareness

Nowakowski, Christopher
Vizzini, Daniel
Gupta, Somak Datta
Raja Sengupta
2012

This paper presents the final results of a connected-vehicles field experiment conducted under the U.S. Department of Transportation's SafeTrip-21 Initiative. A real-time freeway end-of-queue alerting system was developed and tested at 3,400 locations along San Francisco Bay Area freeways in California. The Networked Traveler Foresighted Driving Advanced Driver Assistance System, which used vehicle-to-infrastructure communication, provided drivers with an auditory alert when they approached slow traffic ahead on a freeway to improve the driver's situational awareness. The system was not a...

Overcoming battery life problems of smartphones when creating automated travel diaries

Jariyasunant, Jerald
Raja Sengupta
Joan Walker
2014

Gathering data using travel diaries has been a requirement to analyze travel behaviour data for decades. Traditional pen and paper techniques of gathering data has been complemented by new technologies, most recently GPS loggers, and now smartphones. Smartphones appear to be the silver bullet in collecting travel data on a wide scale, they are widespread, applications are easy to distribute, and the hardware is reliable. However, conserving the battery life in smartphones is a challenge to creating automated travel diaries. The smartphone is not solely a travel diary tool and for a system...

Stability of Dynamic Traveling Repairman Problem Under Polling-Sequencing Policies

Huang, Jiangchuan
Raja Sengupta
2013

We establish a necessary and sufficient condition for stability in the dynamic traveling repairman problem (DTRP) [3] under the class of polling-sequencing (P-S) policies satisfying unlimited-polling and economy of scale. The P-S class includes some of the policies proven to be optimal for the expectation of system time under light and heavy loads in the DTRP literature. The number of tasks inside each polling partition is shown to be a Markov chain. Policies such as first come first serve, traveling salesman policy, nearest neighbor and Daganzo's algorithm are shown to have economy of...

Overcoming Battery Life Problems of Smartphones When Creating Automated Travel Diaries

Jariyasunant, Jerald
Raja Sengupta
Joan Walker
2014

Gathering data using travel diaries has been a requirement to analyze travel behaviour data for decades. Traditional pen and paper techniques of gathering data has been complemented by new technologies, most recently GPS loggers, and now smartphones. Smartphones appear to be the silver bullet in collecting travel data on a wide scale, they are widespread, applications are easy to distribute, and the hardware is reliable. However, conserving the battery life in smartphones is a challenge to creating automated travel diaries. The smartphone is not solely a travel diary tool and for a system...

Protocol Design for Real-Time Estimation Using Wireless Sensors

Fallah, Yaser P.
Raja Sengupta
Ammari, Habib M.
2014

This chapter discusses how a wireless sensor network can be built for real-time estimation purposes. The finite capacity of a wireless network in delivering information means that a real-time estimation process has finite accuracy too. Improving accuracy requires faster sampling and more communication; however, faster communication is not always a possibility due to scalability issues and the limited capacity of a network. In fact, in networks where the wireless medium is shared amongst many nodes, the increase in the amount of communication may even have a negative impact on the capacity...

Quantifying Transit Travel Experiences from the Users’ Perspective with High-resolution Smartphone and Vehicle Location Data: Methodologies, Validation, and Example Analyses

Carrel, Andre
Lau, Peter S. C.
Mishalani, Rabi G.
Raja Sengupta
Joan Walker
2015

While transit agencies have increasingly adopted systems for collecting data on passengers and vehicles, the ability to derive high-resolution passenger trajectories and directly associate them with transit vehicles in a general and transferable manner remains a challenge. In this paper, a system of integrated methods is presented to reconstruct and track travelers usage of transit at a detailed level by matching location data from smartphones to automatic transit vehicle location (AVL) data and by identifying all out-of-vehicle and in-vehicle portions of the passengers trips. High-...

An Unmanned Aerial Traffic Management Solution for Cities Using an Air Parcel Model

Foina, Aislan Gomide
Krainer, Clemens
Raja Sengupta
2015

The Unmanned Aerial System (UAS) market once belonged to professional companies only. Now many amateur pilots fly cheap, smartphone controlled models available in any electronic store. Due to altitude, speed, and weight, these flying objects can cause damage and injury. Hence, a way to manage them is necessary. This paper presents a UAS Traffic Management (UTM) system comprising three components: a UAS electronic identification plate with an embedded logger, a ground identification equipment, and a Traffic Routing System (TRS). This UTM system uses the air parcel model, which divides the...

System Time Distribution of Dynamic Traveling Repairman Problem Under the PART-n-TSP Policy

Huang, Jiangchuan
Raja Sengupta
2015

We propose the PART-n-TSP policy for the Dynamic Traveling Repairman Problem [1]. We compute a good approximation for the distribution of the system time, defined as the elapsed time between the arrival and the completion of each task. PART-n-TSP stabilizes the system for every load in [0; 1). PART-n-TSP has lower system time variance than PARTTSP [14] and Nearest Neighbor [1] when the load is neither too small or too large. We show that PART-n-TSP is also optimal for system time expectation under light and heavy loads.

Collaborative High-Accuracy Localization in Mobile Multipath Environments

Ekambaram, Venkatesan N.
Ramchandran, Kannan
Raja Sengupta
2016

We study the problem of high-accuracy localization of mobile nodes in a multipath-rich environment where submeter accuracy values are required. We employ a peer-to-peer framework where nodes can get pairwise multipath-degraded ranging estimates in local neighborhoods, with the multipath noise correlated across time. The challenge is to enable high-accuracy positioning under severe multipath conditions when the fraction of received signals corrupted by multiple paths is significant. Our contributions are twofold. We provide a practical distributed localization algorithm by invoking an...