Phd Dissertation

Real-time vehicle reidentification system for freeway performance measurements

Abstract

Computational resources in traffic operation fields as well as the bandwidth of field communication links are often quite limited. Accordingly, for real-time implementation of Advanced Transportation Management and Information Systems (ATMIS) strategies, such as vehicle reidentification, there is strong interest in development of field-based techniques and models that can perform satisfactorily while minimizing computational and communication requirements in the field. The ILD (Inductive Loop Detector)-based Vehicle ReiDentification system (ILD-VReID) is an example of a currently applied approach. Although ILDs are not without limitations as a traffic sensor, they are widely used for historical reasons and the sunken investment in the large installed base makes their use in this research highly cost-effective. Therefore, this dissertation develops a new vehicle reidentification algorithm, RTREID-2, for real-time implementation by adopting a PSR (Piecewise Slope Rate) approach that extracts features from raw vehicle signature data. The results of cases studies indicate that RTREID-2 is capable of accurately providing individual vehicle tracking information and performance measurements such as travel time and speed. The potential contributions of RTREID-2 are: application to square and round single loop configurations, and reduced computational requirements associated with re-estimation or transferability of the speed models used in the previously developed approach. As a consequence, RTREID-2 is free of site-specific calibration and transferability issues. A freeway corridor study also demonstrates that RTREID-2 has the potential to be implemented successfully in a congested freeway corridor, utilizing data obtained from both homogenous and heterogeneous loop detection systems. A real-time vehicle classification model, which is based on the PSR approach, was also developed on the part of RTREID-2. The classification model can successfully classify vehicles into 15 classes using single loop detector data without any axle explicit information. The initial results also suggest the potential for transferability of the vehicle classification approach and are very encouraging. To investigate real-time freeway performance measurement in a real-world setting, the design of RTPMS (Real-time Traffic Performance Measurement System) that is based on RTREID-2 is also presented in this dissertation. A simulation of RTPMS is conducted to evaluate its feasibility. The simulation results demonstrate the potential of implementing RTPMS in real world application.

Suggested Citation
Shin-Ting Jeng (2007) Real-time vehicle reidentification system for freeway performance measurements. Ph.D.. University of California, Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/74dcdl/alma991035093275304701 (Accessed: October 14, 2023).

Preprint Journal Article

Can We Trust Embodied Agents? Exploring Backdoor Attacks against Embodied LLM-based Decision-Making Systems

Publication Date

April 30, 2025

Author(s)

Ruochen Jiao, Shaoyuan Xie, Justin Yue, Takami Sato, Lei Wang, Yu-Han (Doris) Wang, Qi Alfred Chen, Qi Zhu

Abstract

Large Language Models (LLMs) have shown significant promise in real-world decision-making tasks for embodied artificial intelligence, especially when fine-tuned to leverage their inherent common sense and reasoning abilities while being tailored to specific applications. However, this fine-tuning process introduces considerable safety and security vulnerabilities, especially in safety-critical cyber-physical systems. In this work, we propose the first comprehensive framework for Backdoor Attacks against LLM-based Decision-making systems (BALD) in embodied AI, systematically exploring the attack surfaces and trigger mechanisms. Specifically, we propose three distinct attack mechanisms: word injection, scenario manipulation, and knowledge injection, targeting various components in the LLM-based decision-making pipeline. We perform extensive experiments on representative LLMs (GPT-3.5, LLaMA2, PaLM2) in autonomous driving and home robot tasks, demonstrating the effectiveness and stealthiness of our backdoor triggers across various attack channels, with cases like vehicles accelerating toward obstacles and robots placing knives on beds. Our word and knowledge injection attacks achieve nearly 100% success rate across multiple models and datasets while requiring only limited access to the system. Our scenario manipulation attack yields success rates exceeding 65%, reaching up to 90%, and does not require any runtime system intrusion. We also assess the robustness of these attacks against defenses, revealing their resilience. Our findings highlight critical security vulnerabilities in embodied LLM systems and emphasize the urgent need for safeguarding these systems to mitigate potential risks.

Suggested Citation
Ruochen Jiao, Shaoyuan Xie, Justin Yue, Takami Sato, Lixu Wang, Yixuan Wang, Qi Alfred Chen and Qi Zhu (2025) “Can We Trust Embodied Agents? Exploring Backdoor Attacks against Embodied LLM-based Decision-Making Systems”. arXiv. Available at: 10.48550/arXiv.2405.20774.

published journal article

Shopping without travel or travel without shopping? an investigation of electronic home shopping

Transport Reviews

Publication Date

October 1, 1997

Abstract

This study explores the growth of electronic home shopping in terms of likely transportation and communication interactions. Although opportunities exist to shop from home today, most consumers initiate travel trips to stores or markets. Widespread use of automobiles has facilitated the retailing configurations we know today but the development of new electronic networks could change this. This study establishes a baseline to explore shopping activities using two-day travel activity data from a large U.S. metropolitan area. It is found that people who telework from home today spend more time engaged in shopping activities than other workers. Potentially, their saved work travel is converted into new trips. In the future, saved shopping travel might be converted into other types of travel, and modelling results show that for busy working women, there is a latent demand for maintenance-related activities. The study results suggest that electronic home shopping will bring into play complex interactions between communications and transportation.

Suggested Citation
Jane Gould and Thomas F. Golob (1997) “Shopping without travel or travel without shopping? an investigation of electronic home shopping”, Transport Reviews, 17(4), pp. 355–376. Available at: 10.1080/01441649708716991.

conference paper

Bayesian analysis of activity participation behavior

Proceedings of the 92nd annual meeting of transportation research board, washington, DC

Publication Date

January 1, 2013
Suggested Citation
M. Allahviranloo and I. Jeliazkov (2013) “Bayesian analysis of activity participation behavior”, in Proceedings of the 92nd annual meeting of transportation research board, washington, DC.

published journal article

Traffic-Related Air Pollution and Incident Dementia: Direct and Indirect Pathways Through Metabolic Dysfunction

Journal of Alzheimer's Disease

Publication Date

August 18, 2020

Author(s)

Kimberly C. Paul, Mary Haan, Yue Yu, Kosuke Inoue, Elizabeth Rose Mayeda, Kristina Dang, Jun Wu, Michael Jerrett, Beate Ritz
Suggested Citation
Kimberly C. Paul, Mary Haan, Yu Yu, Kosuke Inoue, Elizabeth Rose Mayeda, Kristina Dang, Jun Wu, Michael Jerrett and Beate Ritz (2020) “Traffic-Related Air Pollution and Incident Dementia: Direct and Indirect Pathways Through Metabolic Dysfunction”, Journal of Alzheimer's Disease, 76(4), pp. 1477–1491. Available at: 10.3233/JAD-200320.

published journal article

Use of wildfire smoke indicators in health exposure research: high spatial resolution mapping of wildfire-related PM2.5 in California

ISEE Conference Abstracts

Publication Date

September 18, 2022

Author(s)

Nathan Pavlovic, Lianfa Li, Frederick Lurmann, Crystal McClure, Jun Wu, Rima Habre

Abstract

Background: Wildfire smoke is a leading driver of acute exposure to PM2.5 in the American West and a significant contributor to chronic pollution exposure in immediately impacted and further downwind areas. Exposure to wildfire smoke is linked to acute respiratory morbidity and all-cause mortality, yet little is known about chronic effects of repeated, elevated exposures. Inclusion of wildfire smoke in air quality models for health effects research is important for improving accuracy of the overall models and understanding the specific and independent effects of wildfire smoke relative to the entire pollution mixture. However, the nature of smoke, including high spatial variability and the three-dimensional structure of smoke plumes, presents challenges for the accurate representation of wildfire smoke in health research applications. In this presentation, we will discuss exposure and health research applications that use explicit representations of wildfire smoke to improve exposure estimates. Methods:We used dispersion modeling of wildfire smoke to predict ground-level concentrations and support a deep learning ensemble model of PM2.5 over California for 2008-2017. Smoke emissions were modeled using satellite detections of wildfires and a database of emissions related to fire radiative energy. Emissions were dispersed using a fine-scale meteorological data set. We assessed the ability of the model to reproduce spatial and temporal patterns of wildfire smoke using visual satellite imagery of smoke and correlations with ground-based monitoring, respectively. Results: Our results show that the inclusion of smoke dispersion surfaces produces accurate predictions of PM2.5 concentrations in wildfire smoke conditions. Conclusions: This work highlights the importance of incorporating wildfire smoke data sources into exposure assessments, and it indicates new directions for use of wildfire smoke data in health research. The extension of our smoke modeling through the high-smoke years between 2018 and 2021 will support important additional research on wildfire smoke exposure health impacts. Keywords: Wildfire

Suggested Citation
Nathan Pavlovic, Lianfa Li, Frederick Lurmann, Crystal McClure, Jun Wu and Rima Habre (2022) “Use of wildfire smoke indicators in health exposure research: high spatial resolution mapping of wildfire-related PM2.5 in California”, ISEE Conference Abstracts, 2022(1). Available at: 10.1289/isee.2022.P-0241.

published journal article

LiDAR Vehicle Point Cloud Reconstruction Framework for Axle-Based Classification

IEEE Sensors Journal

Suggested Citation
Yiqiao Li, Andre Y. C. Tok, Zhe Sun, Stephen G. Ritchie and Koti Reddy Allu (2023) “LiDAR Vehicle Point Cloud Reconstruction Framework for Axle-Based Classification”, IEEE Sensors Journal, 23(11), pp. 11168–11180. Available at: 10.1109/JSEN.2023.3235301.

published journal article

E-waste bans and U.S. households' preferences for disposing of their e-waste

Journal of Environmental Management

Publication Date

July 1, 2013

Author(s)

Natalia Milovantseva, Jean-Daniel Saphores
Suggested Citation
Natalia Milovantseva and Jean-Daniel Saphores (2013) “E-waste bans and U.S. households' preferences for disposing of their e-waste”, Journal of Environmental Management, 124, pp. 8–16. Available at: 10.1016/j.jenvman.2013.03.019.

published journal article

A Discrete Choice Model for Ordered Alternatives

Econometrica

Publication Date

March 1, 1987

Author(s)

Suggested Citation
Kenneth A. Small (1987) “A Discrete Choice Model for Ordered Alternatives”, Econometrica, 55(2), p. 409. Available at: 10.2307/1913243.