conference paper

Receiver design for Doppler positioning with Leo satellites

ICASSP 2019 - 2019 IEEE international conference on acoustics, speech and signal processing (ICASSP)

Publication Date

May 1, 2019

Abstract

A framework for positioning with low Earth orbit (LEO) satellite signals is proposed. The framework employs an extend Kalman filter (EKF) to estimate a receiver’s position using Doppler frequency measurements from LEO satellites. The satellites’ positions and velocities are known through two-line element (TLE) files. A receiver architecture to acquire and track LEO satellite signals and extract Doppler measurements to LEO satellites is discussed. Simulation results show that 11 m positioning accuracy can be achieved with 25 LEO satellites. Experimental results are presented demonstrating the proposed stationary receiver estimating its position using Doppler measurements from 2 Orbcomm LEO satellites with an accuracy of 360 m over a 1 minute period.

Suggested Citation
Joe J. Khalife and Zaher M. Kassas (2019) “Receiver design for Doppler positioning with Leo satellites”, in ICASSP 2019 - 2019 IEEE international conference on acoustics, speech and signal processing (ICASSP). IEEE (International conference on acoustics speech and signal processing ICASSP), pp. 5506–5510. Available at: 10.1109/icassp.2019.8682554.

Preprint Journal Article

Graph Network Modeling Techniques for Visualizing Human Mobility Patterns

Abstract

Human mobility analysis at urban-scale requires models to represent the complex nature of human movements, which in turn are affected by accessibility to nearby points of interest, underlying socioeconomic factors of a place, and local transport choices for people living in a geographic region. In this work, we represent human mobility and the associated flow of movements as a grapyh. Graph-based approaches for mobility analysis are still in their early stages of adoption and are actively being researched. The challenges of graph-based mobility analysis are multifaceted – the lack of sufficiently high-quality data to represent flows at high spatial and teporal resolution whereas, limited computational resources to translate large voluments of mobility data into a network structure, and scaling issues inherent in graph models etc. The current study develops a methodology by embedding graphs into a continuous space, which alleviates issues related to fast graph matching, graph time-series modeling, and visualization of mobility dynamics. Through experiments, we demonstrate how mobility data collected from taxicab trajectories could be transformed into network structures and patterns of mobility flow changes, and can be used for downstream tasks reporting approx 40% decrease in error on average in matched graphs vs unmatched ones.

Suggested Citation
Sinjini Mitra, Anuj Srivastava, Avipsa Roy and Pavan Turaga (2025) “Graph Network Modeling Techniques for Visualizing Human Mobility Patterns”. arXiv. Available at: 10.48550/ARXIV.2504.03119.

published journal article

Impact of high occupancy vehicle lanes on carpooling behavior

Transportation

Publication Date

February 1, 1990

Author(s)

Genevieve (Gen) Giuliano, Douglas W. Levine, Roger Teal
Suggested Citation
Genevieve Giuliano, Douglas W. Levine and Roger F. Teal (1990) “Impact of high occupancy vehicle lanes on carpooling behavior”, Transportation, 17(2), pp. 159–177. Available at: 10.1007/BF02125334.

published journal article

Comparison of traditional and neural classifiers for Pavement-Crack detection

Journal of Transportation Engineering

Publication Date

July 1, 1994

Author(s)

Suggested Citation
Mohamed S. Kaseko, Zhen-Ping Lo and Stephen G. Ritchie (1994) “Comparison of traditional and neural classifiers for Pavement-Crack detection”, Journal of Transportation Engineering, 120(4), pp. 552–569. Available at: 10.1061/(asce)0733-947x(1994)120:4(552).

Phd Dissertation

Essays on Air Cargo Cost Structures, Airport Traffic, and Airport Delays: Panel Data Analysis of the U.S. Airline Industry

Publication Date

January 1, 2014

Author(s)

Abstract

The present thesis is comprised of four essays that address important gaps in passenger- and cargo-airline research. Seminal studies in airline economics that rely on cross-section methods make critical homogeneity assumptions and preclude time-specific effects. The essays in this thesis use panel data, which allow for certain assumptions made by cross-sectional studies to be relaxed, while shedding light on the intertemporal features of air transport. The first chapter investigates the cost structure of air cargo carriers by applying a total cost model used in passenger-airline studies. Using quarterly panel data (2003-2011) on the domestic operations and costs of FedEx Express and UPS Airlines, empirical results indicate that the air cargo industry exhibits increasing returns to traffic density and constant returns to scale. Accounting for carrier-specific differences in cost structure and network size, FedEx is found to be more cost efficient than UPS (a finding that is reversed when network size is not controlled). Individually, UPS exhibits substantial economies of density and constant returns to scale while FedEx’s cost structure is characterized by weak economies of density and constant returns to scale. Both carriers exhibit economies of size.The next three chapters embody papers that use quarterly panel data of city-level air traffic, airline delay, and socioeconomic variables. Spanning 10 years (2003-2012), the panel structure of the data permits the use of fixed effects to control for city-specific heterogeneity.The second chapter presents a paper prepared for the Airport Cooperative Research Program (ACRP). The study demonstrates the within-city traffic impacts of urban size, employment composition, and wages, providing new insights into the determinants of passenger and air cargo traffic. The essay also confirms that airport traffic is proportional to population, and that service-sector employment and higher wages induce passenger travel and goods movement. A city’s share of manufacturing employment, however, only impacts air cargo traffic. Passenger enplanements exhibit more sensitivity to the proportion of urban workers providing non-tradable services, compared to the share of workers in tradable service jobs.The third chapter, co-authored with Andre Tok, examines the determinants of air cargo traffic in California. The study uses a shorter 7-year panel (2003-2009), and shows that service and manufacturing employment impact the volume of outbound air cargo. Total (domestic) air cargo traffic is found to grow faster than (proportionally to) population, while wages play a significant role in determining both total and domestic air cargo movement. Metro-level air cargo tonnage are also forecasted for the years 2010-2040, indicating that California’s total (domestic) air cargo traffic will increase at an average rate of 5.9 percent (4.4 percent) per year in that period.The final chapter is co-authored with Volodymyr Bilotkach, and it provides the first evidence on the impact of airline delays on urban-sectoral employment. Controlling for unobserved city-specific differences, the empirical estimates of the effects of air traffic on total employment are comparable to previously reported measures. However, service-sector employment is found to be less sensitive to air traffic than other studies suggested. New evidence confirming that delays have a negative impact on employment is also provided, a finding that is robust to various model specifications.

Suggested Citation
Paulos Ashebir Lakew (2014) Essays on Air Cargo Cost Structures, Airport Traffic, and Airport Delays: Panel Data Analysis of the U.S. Airline Industry. UC Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/17uq3m8/alma991002165859704701 (Accessed: October 12, 2023).

working paper

Comparison of Supply, Demand and Cost Models using UMTA Section 15 Data

Publication Date

December 1, 1981

Author(s)

Shirley C. Anderson, Gordon (Pete) Fielding, David Methe

Abstract

To assess the usefulness of the UMTA Section 15 transit data for research, econometric models estimated from previous data sets were replicated. Estimates were prepared for supply, demand and cost equations. Relationships were compared for magnitude, sign and significance. It was found that the 1978-79 Section 15 data can not be used to replicate previous studies. Incomplete returns together with the absence of variables reduce the value of the data set for research. Recommendations are made for improvement of Section 15.

Suggested Citation
Shirley C. Anderson, Gordon J. Fielding and David Methe (1981) Comparison of Supply, Demand and Cost Models using UMTA Section 15 Data. Working Paper UCI-ITS-WP-81-2. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/29g9c7rf.

working paper

An Assessment of the Interaction of the Land-Use Transportation System and Travel Behavior

Publication Date

August 1, 1996

Associated Project

Working Paper

UCI-ITS-WP-96-14, UCI-ITS-AS-WP-96-4

Areas of Expertise

Abstract

This paper presents an empirical assessment of the interaction between the land use – transportation system and travel behavior. A methodology is developed to identify a range of land use-transportation systems using a clustering technique with network and land use inputs. Twenty neighborhoods from Orange County, California were considered in this process. Three groups, or themes, were found to best represent the neighborhoods in the sample area, one each associated with the conventional definition of neotraditional (TND) and planned unit development (PUD) neighborhoods, and one representing neighborhoods which blend characteristics of TND and PUD. Conventional and more complex measures of individual travel behavior were compared via an analysis of variance between the themes to identify significant differences, controlling for socio-economic differences. Research results included the development of (a) a systematic methodology to identify a more explicit land use and transportation dimension, (b) an estimate of the potential effectiveness of design-oriented solutions to reduce automobile congestion using the developed themes, and (c) a preliminary assessment of the extent to which development themes can be utilized to improve the current modeling framework. 

Suggested Citation
Michael G. McNally and Anup Kulkarni (1996) An Assessment of the Interaction of the Land-Use Transportation System and Travel Behavior. Working Paper UCI-ITS-WP-96-14, UCI-ITS-AS-WP-96-4. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/0bb6b827.

Preprint Journal Article

PaniCar: Securing the Perception of Advanced Driving Assistance Systems Against Emergency Vehicle Lighting

Publication Date

May 8, 2025

Author(s)

Elad Feldman, Jacob Shams, Dudi Biton, Qi Alfred Chen, Shaoyuan Xie, Satoru Koda, Yisroel Mirsky, Asaf Shabtai, Yuval Elovici, Ben Nassi

Abstract

The safety of autonomous cars has come under scrutiny in recent years, especially after 16 documented incidents involving Teslas (with autopilot engaged) crashing into parked emergency vehicles (police cars, ambulances, and firetrucks). While previous studies have revealed that strong light sources often introduce flare artifacts in the captured image, which degrade the image quality, the impact of flare on object detection performance remains unclear. In this research, we unveil PaniCar, a digital phenomenon that causes an object detector’s confidence score to fluctuate below detection thresholds when exposed to activated emergency vehicle lighting. This vulnerability poses a significant safety risk, and can cause autonomous vehicles to fail to detect objects near emergency vehicles. In addition, this vulnerability could be exploited by adversaries to compromise the security of advanced driving assistance systems (ADASs). We assess seven commercial ADASs (Tesla Model 3, “manufacturer C”, HP, Pelsee, AZDOME, Imagebon, Rexing), four object detectors (YOLO, SSD, RetinaNet, Faster R-CNN), and 14 patterns of emergency vehicle lighting to understand the influence of various technical and environmental factors. We also evaluate four SOTA flare removal methods and show that their performance and latency are insufficient for real-time driving constraints. To mitigate this risk, we propose Caracetamol, a robust framework designed to enhance the resilience of object detectors against the effects of activated emergency vehicle lighting. Our evaluation shows that on YOLOv3 and Faster RCNN, Caracetamol improves the models’ average confidence of car detection by 0.20, the lower confidence bound by 0.33, and reduces the fluctuation range by 0.33. In addition, Caracetamol is capable of processing frames at a rate of between 30-50 FPS, enabling real-time ADAS car detection.

Suggested Citation
Elad Feldman, Jacob Shams, Dudi Biton, Alfred Chen, Shaoyuan Xie, Satoru Koda, Yisroel Mirsky, Asaf Shabtai, Yuval Elovici and Ben Nassi (2025) “PaniCar: Securing the Perception of Advanced Driving Assistance Systems Against Emergency Vehicle Lighting”. arXiv. Available at: 10.48550/arXiv.2505.05183.

published journal article

Development of methodology to design advanced traffic surveillance systems for traffic information based on Or­i­gin-Des­tin­a­tion

Transportation Research Record

Publication Date

January 1, 2005
Suggested Citation
Cheol Oh and Stephen G. Ritchie (2005) “Development of methodology to design advanced traffic surveillance systems for traffic information based on Or­i­gin-Des­tin­a­tion”, Transportation Research Record, 1935(1), pp. 37–46. Available at: 10.1177/0361198105193500105.