+publisher:"University of Michigan" +contributor:("Liu, Henry")

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University of Michigan

1. Zheng, Jianfeng. Data-Driven Applications for Connected Vehicle Based Traffic Signal Systems.

Degree: PhD, Civil Engineering, 2016, University of Michigan

URL: http://hdl.handle.net/2027.42/135875

► Massive deployment of connected vehicles (CVs) is now on the horizon, and will undoubtedly introduce paradigm shifts to the transportation system. At signalized intersections, CV… (more)

▼ Massive deployment of connected vehicles (CVs) is now on the horizon, and will undoubtedly introduce paradigm shifts to the transportation system. At signalized intersections, CV can receive real-time traffic information from roadside equipment (RSE) so that driver can be advised for safer driving, while signal controllers can receive vehicle position and speed information for more effective operation. Considering signalized intersections are often hot-spots of traffic congestion and driver frustration, tremendous opportunities exist to improve the effectiveness and efficiency of traffic signal operation with CV data. However, due to the lack of real-world CVs, the benefit of CV data for signal operation has yet been explored. This limitation has now been partially overcome with the safety pilot model deployment (SPMD) project, the world's first large-scale CV deployment project with around 2,800 CVs. Through leveraging the SPMD project, this dissertation is the first-ever effort of analyzing large amount real-world CV data to improve traffic signal system operation. Three innovative traffic signal applications are developed to explore the benefit of CV data with low penetration rates. Firstly, to facilitate the deployment of Vehicle-to-Infrastructure (V2I) systems at intersections, a procedure is developed for automatic generation of intersection map, a critical element of many CV applications. Using data from RSE, the proposed approach can automatically estimate intersection geometry and lane-phase mapping, and serve as a cost-effective alternative to prepare input for RSE deployment. Secondly, to pave the way for detector-free signal operation, an algorithm is developed for estimating traffic volumes with CV data. This application could help reduce the dependency of traffic signals on vehicle detectors, and would be particularly beneficial for signal operation. Lastly, to explore the benefit of V2I communication for driving assistance, a speed advisory system is proposed to help drivers reduce fuel consumption when driving through intersections, using information from RSEs. An efficient algorithm is proposed based on Pontryagin's maximum principle for real time implementation. With the three applications to improve traffic signal system in three different perspectives, the ultimate objective of this dissertation is to facilitate development and deployment of CV-based traffic signal system in the near future. Advisors/Committee Members: Liu, Henry (committee member), Peng, Huei (committee member), Kerkez, Branko (committee member), Sayer, James R (committee member).

Subjects/Keywords: Connected Vehicle; Traffic Signal; Data Analysis; DSRC; GPS Trajectory Data; Safety Pilot Model Deployment Project; Civil and Environmental Engineering; Engineering

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APA (6^th Edition):

Zheng, J. (2016). Data-Driven Applications for Connected Vehicle Based Traffic Signal Systems. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/135875

Chicago Manual of Style (16^th Edition):

Zheng, Jianfeng. “Data-Driven Applications for Connected Vehicle Based Traffic Signal Systems.” 2016. Doctoral Dissertation, University of Michigan. Accessed April 19, 2021. http://hdl.handle.net/2027.42/135875.

MLA Handbook (7^th Edition):

Zheng, Jianfeng. “Data-Driven Applications for Connected Vehicle Based Traffic Signal Systems.” 2016. Web. 19 Apr 2021.

Vancouver:

Zheng J. Data-Driven Applications for Connected Vehicle Based Traffic Signal Systems. [Internet] [Doctoral dissertation]. University of Michigan; 2016. [cited 2021 Apr 19]. Available from: http://hdl.handle.net/2027.42/135875.

Council of Science Editors:

Zheng J. Data-Driven Applications for Connected Vehicle Based Traffic Signal Systems. [Doctoral Dissertation]. University of Michigan; 2016. Available from: http://hdl.handle.net/2027.42/135875

University of Michigan

2. Zhang, Xiaowu. Design of Power Split Hybrid Powertrains with Multiple Planetary Gears and Clutches.

Degree: PhD, Mechanical Engineering, 2015, University of Michigan

URL: http://hdl.handle.net/2027.42/116659

► Fuel economy standards for automobiles have become much tighter in many countries in the past decades. Hybrid electric vehicles (HEVs), as one of the most… (more)

▼ Fuel economy standards for automobiles have become much tighter in many countries in the past decades. Hybrid electric vehicles (HEVs), as one of the most promising solutions to take on these challenging standards, have been successful in the US market. In the last few years, an observed trend is to use multiple planetary gears with multiple operating modes to further improve vehicle fuel economy and driving performance. Most work in existing literature on HEV design and optimization has been based on specific configurations, rather than exhaustively searching through all possible configurations. This limitation arises from the large size of the design space–millions to trillions of possible topological candidates. In this dissertation, a systematic design methodology is presented, which enables the exhaustive search of multi-mode powertrain systems. As a first step, a systematic analysis has been performed for all 12 single PG configurations with multiple operating modes enabled by clutch operation. The Dynamic Programming (DP) technique is used to solve the optimal energy management problems for each design candidate. For multi-mode HEVs with multiple PGs, an automated modeling and mode classification methodology is developed, which makes it possible to exhaustively search all possible designs. General mode shift mechanisms are studied, while mode shift cost is evaluated using Dijkstra’s algorithm, which identifies the optimal mode shift path. For each candidate, the optimal control problem needs to be solved so that all designs can be compared based on their best possible execution. A fast and near-optimal energy management strategy is proposed. The comparison results show that it is up to 10,000 times faster than DP while achieving similar performance. To ensure acceptable launching performance of the design candidates, a fast and optimal acceleration performance test procedure is developed, which can be used to determine optimal control inputs and mode shift schedule. Combining all proposed methodologies produces a systematic and optimal design procedure. Optimization results show that the exhaustive search design method is able to identify dozens of better designs than the production hybrid vehicle models available in today’s market. Advisors/Committee Members: Peng, Huei (committee member), Sun, Jing (committee member), Liu, Henry (committee member), Stein, Jeffrey L (committee member).

Subjects/Keywords: Hybrid Vehicle; Optimal Control; Optimal Design; Planetary Gear; Mechanical Engineering; Engineering

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APA (6^th Edition):

Zhang, X. (2015). Design of Power Split Hybrid Powertrains with Multiple Planetary Gears and Clutches. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/116659

Chicago Manual of Style (16^th Edition):

Zhang, Xiaowu. “Design of Power Split Hybrid Powertrains with Multiple Planetary Gears and Clutches.” 2015. Doctoral Dissertation, University of Michigan. Accessed April 19, 2021. http://hdl.handle.net/2027.42/116659.

MLA Handbook (7^th Edition):

Zhang, Xiaowu. “Design of Power Split Hybrid Powertrains with Multiple Planetary Gears and Clutches.” 2015. Web. 19 Apr 2021.

Vancouver:

Zhang X. Design of Power Split Hybrid Powertrains with Multiple Planetary Gears and Clutches. [Internet] [Doctoral dissertation]. University of Michigan; 2015. [cited 2021 Apr 19]. Available from: http://hdl.handle.net/2027.42/116659.

Council of Science Editors:

Zhang X. Design of Power Split Hybrid Powertrains with Multiple Planetary Gears and Clutches. [Doctoral Dissertation]. University of Michigan; 2015. Available from: http://hdl.handle.net/2027.42/116659

University of Michigan

3. Huang, Xianan. Eco-Mobility-on-Demand Service with Ride-Sharing.

Degree: PhD, Mechanical Engineering, 2019, University of Michigan

URL: http://hdl.handle.net/2027.42/153446

► Connected Automated Vehicles (CAV) technologies are developing rapidly, and one of its more popular application is to provide mobility-on-demand (MOD) services. However, with CAVs on… (more)

▼ Connected Automated Vehicles (CAV) technologies are developing rapidly, and one of its more popular application is to provide mobility-on-demand (MOD) services. However, with CAVs on the road, the fuel consumption of surface transportation may increase significantly. Travel demands could increase due to more accessible travel provided by the flexible service compared with the current public transit system. Trips from current underserved population and mode shift from walking and public transit could also increase travel demands significantly. In this research, we explore opportunities for the fuel-saving of CAVs in an urban environment from different scales, including speed trajectory optimization at intersections, data-drive fuel consumption model and eco-routing algorithm development, and eco-MOD fleet assignment. First, we proposed a speed trajectory optimization algorithm at signalized intersections. Although the optimal solution can be found through dynamic programming, the curse of dimensionality limits its computation speed and robustness. Thus, we propose the sequential approximation approach to solve a sequence of mixed integer optimization problems with quadratic objective and linear constraints. The speed and acceleration constraints at intersections due to route choice are addressed using a barrier method. In this work, we limit the problem to a single intersection due to the route choice application and only consider free flow scenarios, but the algorithm can be extended to multiple intersections and congested scenarios where a leading vehicle is included as a constraint if an intersection driver model is available. Next, we developed a fuel consumption model for route optimization. The mesoscopic fuel consumption model is developed through a data-driven approach considering the tradeoff between model complexity and accuracy. To develop the model, a large quantity of naturalistic driving data is used. Since the selected dataset doesn’t contain fuel consumption data, a microscopic fuel consumption simulator, Autonomie, is used to augment the information. Gaussian Mixture Regression is selected to build the model due to its ability to address nonlinearity. Instead of selected component number by cross-validation, we use the Bayesian formulation which models the indicator of components as a random variable which has Dirichlet distribution as prior. The model is used to estimate fuel consumption cost for routing algorithm. In this part, we assume the traffic network is static. Finally, the fuel consumption model and the eco-routing algorithm are integrated with the MOD fleet assignment. The MOD control framework models customers’ travel time requirements are as constraints, thus provides flexibility for cost function design. At the current phase, we assume the traffic network is static and use offline calculated travel time and fuel consumption to assign the fleet. To rebalance the idling vehicles, we developed a traffic network partition algorithm which minimizing the expected travel time within each… Advisors/Committee Members: Peng, Huei (committee member), Liu, Henry (committee member), Auld, Joshua A. (committee member), Gorodetsky, Alex Arkady (committee member), Huan, Xun (committee member).

Subjects/Keywords: mobility-on-demand; Connected Automated Vehicles; energy consumption; routing; speed optimization; Mechanical Engineering; Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Huang, X. (2019). Eco-Mobility-on-Demand Service with Ride-Sharing. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/153446

Chicago Manual of Style (16^th Edition):

Huang, Xianan. “Eco-Mobility-on-Demand Service with Ride-Sharing.” 2019. Doctoral Dissertation, University of Michigan. Accessed April 19, 2021. http://hdl.handle.net/2027.42/153446.

MLA Handbook (7^th Edition):

Huang, Xianan. “Eco-Mobility-on-Demand Service with Ride-Sharing.” 2019. Web. 19 Apr 2021.

Vancouver:

Huang X. Eco-Mobility-on-Demand Service with Ride-Sharing. [Internet] [Doctoral dissertation]. University of Michigan; 2019. [cited 2021 Apr 19]. Available from: http://hdl.handle.net/2027.42/153446.

Council of Science Editors:

Huang X. Eco-Mobility-on-Demand Service with Ride-Sharing. [Doctoral Dissertation]. University of Michigan; 2019. Available from: http://hdl.handle.net/2027.42/153446

University of Michigan

4. Zhao, Yan. Traffic State Estimation Using Probe Vehicle Data.

Degree: PhD, Mechanical Engineering, 2020, University of Michigan

URL: http://hdl.handle.net/2027.42/155289

► Traffic problems are becoming a burden on cities across the world. To prevent traffic accidents, mitigate congestion, and reduce fuel consumption, a critical step is… (more)

▼ Traffic problems are becoming a burden on cities across the world. To prevent traffic accidents, mitigate congestion, and reduce fuel consumption, a critical step is to have a good understanding of traffic. Traditionally, traffic conditions are monitored primarily by fixed-location sensors. However, fixed-location sensors only provide information about specific locations, and the installation and maintenance cost is very high. The advances in gls{gps}-based technologies, such as connected vehicles and ride-hailing services, provide us an alternative approach to traffic monitoring. While these types of gls{gps}-equipped probe vehicles travel on the road, a vast amount of trajectory data are being collected. As probe vehicle data contain rich information about traffic conditions, they have drawn much attention from both researchers and practitioners in the field of traffic management and control. Extensive literature has studied the estimation of traffic speeds and travel times using probe vehicle data. However, as for queue lengths and traffic volumes, which are critical for traffic signal control and performance measures, most of the existing estimation methods based on probe vehicles can hardly be implemented in practice. The main obstacle is the low market penetration of probe vehicles. Therefore, in this dissertation, we aim to develop probe vehicle based traffic state estimation methods that are suitable for the low penetration rate environment and can potentially be implemented in the real world. First, we treat the traffic state in each location and each time point independently. We focus on estimating the queues forming at isolated intersections under light or moderate traffic. The existing methods often require prior knowledge of the queue length distribution or the probe vehicle penetration rate. However, these parameters are not available beforehand in real life. Therefore, we propose a series of methods to estimate these parameters from historical probe vehicle data. Some of the methods have been validated using real-world probe vehicle data. Second, we study traffic state estimation considering temporal correlations. The correlation of queue lengths in different traffic signal cycles is often ignored by the existing studies, although the phenomenon is commonly-observed in real life, such as the overflow queues induced by oversaturated traffic. To fill the gap, we model such queueing processes and observation processes using a hidden Markov model (gls{hmm}). Based on the gls{hmm}, we develop two cycle-by-cycle queue length estimation methods and an algorithm that can estimate the parameters of the gls{hmm} from historical probe vehicle data. Lastly, we consider the spatiotemporal correlations of traffic states, with a focus on the estimation of traffic volumes. With limited probe vehicle data, it is difficult to estimate traffic volumes accurately if we treat each location and each time slot independently. Noticing that traffic volumes in different locations and different time slots are correlated, we… Advisors/Committee Members: Liu, Henry (committee member), Peng, Huei (committee member), Yin, Yafeng (committee member), Masoud, Neda (committee member), Orosz, Gabor (committee member).

Subjects/Keywords: Traffic state estimation; Probe vehicle; Data mining; Transportation; Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Zhao, Y. (2020). Traffic State Estimation Using Probe Vehicle Data. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/155289

Chicago Manual of Style (16^th Edition):

Zhao, Yan. “Traffic State Estimation Using Probe Vehicle Data.” 2020. Doctoral Dissertation, University of Michigan. Accessed April 19, 2021. http://hdl.handle.net/2027.42/155289.

MLA Handbook (7^th Edition):

Zhao, Yan. “Traffic State Estimation Using Probe Vehicle Data.” 2020. Web. 19 Apr 2021.

Vancouver:

Zhao Y. Traffic State Estimation Using Probe Vehicle Data. [Internet] [Doctoral dissertation]. University of Michigan; 2020. [cited 2021 Apr 19]. Available from: http://hdl.handle.net/2027.42/155289.

Council of Science Editors:

Zhao Y. Traffic State Estimation Using Probe Vehicle Data. [Doctoral Dissertation]. University of Michigan; 2020. Available from: http://hdl.handle.net/2027.42/155289

University of Michigan

5. Huang, Shihong. Cyber Security of Traffic Signal Control Systems with Connected Vehicles.

Degree: PhD, Civil Engineering, 2020, University of Michigan

URL: http://hdl.handle.net/2027.42/162931

► Our world is becoming increasingly connected through smart technologies. The same trend is emerging in transportation systems, wherein connected vehicles (CVs) and transportation infrastructure are… (more)

▼ Our world is becoming increasingly connected through smart technologies. The same trend is emerging in transportation systems, wherein connected vehicles (CVs) and transportation infrastructure are being connected through advanced wireless communication technologies. CVs have great potential to improve a variety of mobility applications, including traffic signal control (TSC), a critical component in urban traffic operations. CV-based TSC (CV-TSC) systems use trajectory data to make more informed control decisions, therefore can accommodate real-time traffic fluctuations more efficiently. However, vehicle-infrastructure connectivity opens new doors to potential cyber attacks. Malicious attackers can potentially send falsified trajectory data to CV-TSC systems and influence signal control decisions. The benefit of CV-TSC systems can be realized only if the systems are secure in cyberspace. Although many CV-TSC systems have been developed within the past decade, few consider cyber security in their system design. It remains unclear exactly how vulnerable CV-TSC systems are, how cyber attacks may be perpetrated, and how engineers can mitigate cyber attacks and protect CV-TSC systems. Therefore, this dissertation aims to systematically understand the cyber security problems facing CV-TSC systems under falsified data attacks and provide a countermeasure to safeguard CV-TSC systems. These objectives are accomplished through four studies. The first study evaluates the effects of falsified data attacks on TSC systems. Two TSC systems are considered: a conventional actuated TSC system and an adaptive CV-TSC system. Falsified data attacks are assumed to change the input data to these systems and therefore influence control decisions. Numerical examples show that both systems are vulnerable to falsified data attacks. The second study investigates how falsified data attacks may be perpetrated in a realistic setting. Different from prior research, this study considers a more realistic but challenging black-box attack scenario, in which the signal control model is unavailable to the attacker. Under this constraint, the attacker has to learn the signal control model using a surrogate model. The surrogate model predicts signal timing plans based on critical traffic features extracted from CV data. The attacker can generate falsified CV data (i.e., falsified vehicle trajectories) to alter the values of critical traffic features and thus influence signal control decisions. In the third study, a data-driven method is proposed to protect CV-TSC systems from falsified data attacks. Falsified trajectories are behaviorally distinct from normal trajectories because they must accomplish a certain attack goal; thus, the problem of identifying falsified trajectories is considered an abnormal trajectory identification problem. A trajectory-embedding model is developed to generate vector representations of trajectory data. The similarity (distance) between each pair of trajectories can be computed based on these vector representations.… Advisors/Committee Members: Liu, Henry (committee member), Mao, Z Morley (committee member), Masoud, Neda (committee member), Yin, Yafeng (committee member).

Subjects/Keywords: Cyber security; Traffic signal control; Connected vehicle; Falsified data attack; Engineering (General); Transportation; Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Huang, S. (2020). Cyber Security of Traffic Signal Control Systems with Connected Vehicles. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/162931

Chicago Manual of Style (16^th Edition):

Huang, Shihong. “Cyber Security of Traffic Signal Control Systems with Connected Vehicles.” 2020. Doctoral Dissertation, University of Michigan. Accessed April 19, 2021. http://hdl.handle.net/2027.42/162931.

MLA Handbook (7^th Edition):

Huang, Shihong. “Cyber Security of Traffic Signal Control Systems with Connected Vehicles.” 2020. Web. 19 Apr 2021.

Vancouver:

Huang S. Cyber Security of Traffic Signal Control Systems with Connected Vehicles. [Internet] [Doctoral dissertation]. University of Michigan; 2020. [cited 2021 Apr 19]. Available from: http://hdl.handle.net/2027.42/162931.

Council of Science Editors:

Huang S. Cyber Security of Traffic Signal Control Systems with Connected Vehicles. [Doctoral Dissertation]. University of Michigan; 2020. Available from: http://hdl.handle.net/2027.42/162931

University of Michigan

6. Sun, Xiaotong. Facilitating Cooperative Truck Platooning for Energy Savings: Path Planning, Platoon Formation and Benefit Redistribution.

Degree: PhD, Civil Engineering, 2020, University of Michigan

URL: http://hdl.handle.net/2027.42/163047

► Enabled by the connected and automated vehicle (CAV) technology, cooperative truck platooning that offers promising energy savings is likely to be implemented soon. However, as… (more)

▼ Enabled by the connected and automated vehicle (CAV) technology, cooperative truck platooning that offers promising energy savings is likely to be implemented soon. However, as the trucking industry operates in a highly granular manner so that the trucks usually vary in their operation schedules, vehicle types and configurations, it is inevitable that 1) the spontaneous platooning over a spatial network is rare, 2) the total fuel savings vary from platoon to platoon, and 3) the benefit achieved within a platoon differs from position to position, e.g., the lead vehicle always achieves the least fuel-saving. Consequently, trucks from different owners may not have the opportunities to platoon with others if no path coordination is performed. Even if they happen to do so, they may tend to change positions in the formed platoons to achieve greater benefits, yielding behaviorally unstable platoons with less energy savings and more disruptions to traffic flows. This thesis proposes a hierarchical modeling framework to explicate the necessitated strategies that facilitate cooperative truck platooning. An empirical study is first conducted to scrutinize the energy-saving potentials of the U.S. national freight network. By comparing the performance under scheduled platooning and ad-hoc platooning, the author shows that the platooning opportunities can be greatly improved by careful path planning, thereby yielding substantial energy savings. For trucks assembled on the same path and can to platoon together, the second part of the thesis investigates the optimal platoon formation that maximizes total platooning utility and benefits redistribution mechanisms that address the behavioral instability issue. Both centralized and decentralized approaches are proposed. In particular, the decentralized approach employs a dynamic process where individual trucks or formed platoons are assumed to act as rational agents. The agents decide whether to form a larger, better platoon considering their own utilities under the pre-defined benefit reallocation mechanisms. Depending on whether the trucks are single-brand or multi-brand, whether there is a complete information setting or incomplete information setting, three mechanisms, auction, bilateral trade model, and one-sided matching are proposed. The centralized approach yields a near-optimal solution for the whole system and is more computationally efficient than conventional algorithms. The decentralized approach is stable, more flexible, and computational efficient while maintaining acceptable degrees of optimality. The mechanisms proposed can apply to not only under the truck platooning scenario but also other forms of shared mobility. Advisors/Committee Members: Yin, Yafeng (committee member), Shen, Siqian May (committee member), Liu, Henry (committee member), Masoud, Neda (committee member).

Subjects/Keywords: cooperative truck platooning; energy-saving potentials; benefit reallocation mechanisms; optimal platoon formation; shared mobility; Civil and Environmental Engineering; Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sun, X. (2020). Facilitating Cooperative Truck Platooning for Energy Savings: Path Planning, Platoon Formation and Benefit Redistribution. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/163047

Chicago Manual of Style (16^th Edition):

Sun, Xiaotong. “Facilitating Cooperative Truck Platooning for Energy Savings: Path Planning, Platoon Formation and Benefit Redistribution.” 2020. Doctoral Dissertation, University of Michigan. Accessed April 19, 2021. http://hdl.handle.net/2027.42/163047.

MLA Handbook (7^th Edition):

Sun, Xiaotong. “Facilitating Cooperative Truck Platooning for Energy Savings: Path Planning, Platoon Formation and Benefit Redistribution.” 2020. Web. 19 Apr 2021.

Vancouver:

Sun X. Facilitating Cooperative Truck Platooning for Energy Savings: Path Planning, Platoon Formation and Benefit Redistribution. [Internet] [Doctoral dissertation]. University of Michigan; 2020. [cited 2021 Apr 19]. Available from: http://hdl.handle.net/2027.42/163047.

Council of Science Editors:

Sun X. Facilitating Cooperative Truck Platooning for Energy Savings: Path Planning, Platoon Formation and Benefit Redistribution. [Doctoral Dissertation]. University of Michigan; 2020. Available from: http://hdl.handle.net/2027.42/163047

7. Fishelson, James. Planning for a Shared Automated Transportation Future.

Degree: PhD, Urban and Regional Planning, 2018, University of Michigan

URL: http://hdl.handle.net/2027.42/144009

► Vehicle automation represents the greatest revolution in transportation since the automobile itself. However, the greater the potential impact of a new technology, the harder the… (more)

▼ Vehicle automation represents the greatest revolution in transportation since the automobile itself. However, the greater the potential impact of a new technology, the harder the future is to predict; the nature of revolutionary advances is that they are not incremental, and they will be used in far different ways than what came before them. For automated vehicles, this could include wholesale shift towards shared automated vehicles (SAVs), similar to self-driving taxis. While SAVs are not a panacea for problems of the transportation system, this dissertation is based on the premise that an SAV future is far more desirable than one dominated by privately owned and operated AVs (PAVs). Automation in concert with private ownership would encourage more sprawling development, more vehicle kilometers traveled, more congestion, more emissions, and more inequality. This dissertation seeks to understand and model the conditions under which SAVs are more likely to succeed. It constructs a simplified and flexible agent-based model to test system performance under a wide variety of situations, including varying fleet size, urban density, and urban form. By performing sensitivity analyses on these independent variables, this model is able to identify tipping points and other non-linear performance trends. For example, when fleet sizes increase, overall wait times and relocation percentages (the time/distance the vehicle must travel while empty) decrease, albeit at sharply reducing rates. As long as fleet sizes are sufficiently large to avoid queuing, which occurs when there are more trip requests than available vehicles, further fleet size increases does not substantially improve performance. When urban density increases, overall SAV system performance also increases at decreasing rates. SAV systems do not appear to be viable for densities much lower than approximately 500 people per km2. However, there is not a huge increase in performance when going from medium density (e.g. Ann Arbor) to high density (e.g. Manhattan); SAV systems could work in both kinds of places. Varying urban form has a somewhat more complex relationship with SAV performance. The most important points are that is that trips to the less dense outskirts of a city are more difficult and expensive to serve than those in the city center, and that once trip distance is controlled for, the benefits from serving the denser central areas are more than outweighed by the costs of having to serve the outskirts when compared to a base city with constant density throughout. The final modelling runs examine mode choice, comparing SAVs with transit and PAVs across different urban densities. These results suggest that SAVs obtain their greatest mode share over medium densities between approximately 500 and 4,000 people per km2, but never more than 13% of all trips. While on their own, SAVs are not sufficient to break the dominance of private vehicles, they can act as a supplement to transit, helping to provide rides that would be otherwise too difficult or expensive… Advisors/Committee Members: Levine, Jonathan (committee member), Liu, Henry (committee member), Grengs, Joseph Donald (committee member), Hampshire, Robert Cornelius (committee member).

Subjects/Keywords: Shared Automated Vehicles; Shared Mobility; Agent-Based Modelling; Vehicle Automation; Ridesourcing; Civil and Environmental Engineering; Transportation; Urban Planning; Engineering; Social Sciences

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APA (6^th Edition):

Fishelson, J. (2018). Planning for a Shared Automated Transportation Future. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/144009

Chicago Manual of Style (16^th Edition):

Fishelson, James. “Planning for a Shared Automated Transportation Future.” 2018. Doctoral Dissertation, University of Michigan. Accessed April 19, 2021. http://hdl.handle.net/2027.42/144009.

MLA Handbook (7^th Edition):

Fishelson, James. “Planning for a Shared Automated Transportation Future.” 2018. Web. 19 Apr 2021.

Vancouver:

Fishelson J. Planning for a Shared Automated Transportation Future. [Internet] [Doctoral dissertation]. University of Michigan; 2018. [cited 2021 Apr 19]. Available from: http://hdl.handle.net/2027.42/144009.

Council of Science Editors:

Fishelson J. Planning for a Shared Automated Transportation Future. [Doctoral Dissertation]. University of Michigan; 2018. Available from: http://hdl.handle.net/2027.42/144009

8. Chen, Qi. Proactive Vulnerability Discovery and Assessment in Smart, Connected Systems Through Systematic Problem Analysis.

Degree: PhD, Computer Science & Engineering, 2018, University of Michigan

URL: http://hdl.handle.net/2027.42/145981

► The world is increasingly connected through a series of smart, connected systems such as smartphone systems, smart home systems, and emerging smart transportation and autonomous… (more)

▼ The world is increasingly connected through a series of smart, connected systems such as smartphone systems, smart home systems, and emerging smart transportation and autonomous vehicle systems. While leading to improved services, such transformation also introduces new security challenges. To address these challenges, in contrast to existing defense mechanisms that are mostly ad hoc and reactive, my dissertation research is dedicated to developing systematic problem analysis approaches that can proactively discover and assess new security problems in smart, connected systems. To achieve this goal, my dissertation focuses on two most fundamental capabilities in any smart, connected system: network stack and smart control, and demonstrates that static/dynamic program analysis and network measurement can be used to systematically identify new code-level and network-level security challenges in smart, connected systems, and gain insights about problem severity to address design trade-offs in the defense solutions. More specifically, my research is able to leverage these techniques to discover a new attack vector (US-CERT alert TA16-144A) that is unexpectedly brought by the recent expansion in the DNS system, and new algorithm-level security vulnerabilities in the next-generation smart transportation systems. For these discoveries, systematic vulnerability cause analysis is performed subsequently to uncover the associated new network-level and code-level security challenges. On the defense side, these techniques are also used in my dissertation research to build the first automated detection tool for packet injection vulnerability, a recurring problem in network communication protocols, and define more useful attack surface to balance the design trade-off in name collision attack defenses. Advisors/Committee Members: Mao, Z Morley (committee member), Liu, Henry (committee member), Prakash, Atul (committee member), Qian, Zhiyun (committee member), Reiter, Michael K. (committee member).

Subjects/Keywords: Software security; Vulnerability discovery and analysis; IoT/CPS security; Smart system security; Network measurement; Network and systems security; Computer Science; Engineering; Science

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APA (6^th Edition):

Chen, Q. (2018). Proactive Vulnerability Discovery and Assessment in Smart, Connected Systems Through Systematic Problem Analysis. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/145981

Chicago Manual of Style (16^th Edition):

Chen, Qi. “Proactive Vulnerability Discovery and Assessment in Smart, Connected Systems Through Systematic Problem Analysis.” 2018. Doctoral Dissertation, University of Michigan. Accessed April 19, 2021. http://hdl.handle.net/2027.42/145981.

MLA Handbook (7^th Edition):

Chen, Qi. “Proactive Vulnerability Discovery and Assessment in Smart, Connected Systems Through Systematic Problem Analysis.” 2018. Web. 19 Apr 2021.

Vancouver:

Chen Q. Proactive Vulnerability Discovery and Assessment in Smart, Connected Systems Through Systematic Problem Analysis. [Internet] [Doctoral dissertation]. University of Michigan; 2018. [cited 2021 Apr 19]. Available from: http://hdl.handle.net/2027.42/145981.

Council of Science Editors:

Chen Q. Proactive Vulnerability Discovery and Assessment in Smart, Connected Systems Through Systematic Problem Analysis. [Doctoral Dissertation]. University of Michigan; 2018. Available from: http://hdl.handle.net/2027.42/145981

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Open Access Theses and Dissertations