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Full-Text Articles in Physical Sciences and Mathematics

Segac: Sample Efficient Generalized Actor Critic For The Stochastic On-Time Arrival Problem, Honglian Guo, Zhi He, Wenda Sheng, Zhiguang Cao, Yingjie Zhou, Weinan Gao Jan 2024

Segac: Sample Efficient Generalized Actor Critic For The Stochastic On-Time Arrival Problem, Honglian Guo, Zhi He, Wenda Sheng, Zhiguang Cao, Yingjie Zhou, Weinan Gao

Research Collection School Of Computing and Information Systems

This paper studies the problem in transportation networks and introduces a novel reinforcement learning-based algorithm, namely. Different from almost all canonical sota solutions, which are usually computationally expensive and lack generalizability to unforeseen destination nodes, segac offers the following appealing characteristics. segac updates the ego vehicle’s navigation policy in a sample efficient manner, reduces the variance of both value network and policy network during training, and is automatically adaptive to new destinations. Furthermore, the pre-trained segac policy network enables its real-time decision-making ability within seconds, outperforming state-of-the-art sota algorithms in simulations across various transportation networks. We also successfully deploy segac …


Transportation Asset Management For The Electric Road System, Kamalen Maria Santos Diaz Dec 2022

Transportation Asset Management For The Electric Road System, Kamalen Maria Santos Diaz

Open Access Theses & Dissertations

Electric road systems (ERS) have been presented as a new solution towards a sustainable transportation future, fueling the widespread adoption of electric vehicles by eliminating range anxiety, reducing battery size, and being regional friendly. These systems consist of four components: electric power supply, roads, vehicles, and operations. Much of the early research conducted on ERS has been on how to initially construct these systems by focusing on the first three components, however, there is limited knowledge on how ERS will impact traditional road operations after the systems are in place. Transportation Asset Management (TAM), a major focus within the transportation …


Multi-Agent Reinforcement Learning For Traffic Signal Control Through Universal Communication Method, Qize Jiang, Minhao Qin, Shengmin Shi, Weiwei Sun Sun, Baihua Zheng Jul 2022

Multi-Agent Reinforcement Learning For Traffic Signal Control Through Universal Communication Method, Qize Jiang, Minhao Qin, Shengmin Shi, Weiwei Sun Sun, Baihua Zheng

Research Collection School Of Computing and Information Systems

How to coordinate the communication among intersections effectively in real complex traffic scenarios with multi-intersection is challenging. Existing approaches only enable the communication in a heuristic manner without considering the content/importance of information to be shared. In this paper, we propose a universal communication form UniComm between intersections. UniComm embeds massive observations collected at one agent into crucial predictions of their impact on its neighbors, which improves the communication efficiency and is universal across existing methods. We also propose a concise network UniLight to make full use of communications enabled by UniComm. Experimental results on real datasets demonstrate that UniComm …


Perceived Social And Environmental Impacts Of The Maya Train Project On The Yucatan Peninsula Of Mexico: A Case Study Of Puerto Morelos, Emely Hernandez Yac Jan 2022

Perceived Social And Environmental Impacts Of The Maya Train Project On The Yucatan Peninsula Of Mexico: A Case Study Of Puerto Morelos, Emely Hernandez Yac

Graduate Research Theses & Dissertations

The Maya Train Project (MTP) is a new national megaproject in Mexico, meant to connect the perimeter of the Yucatan Peninsula, and facilitate easier transportation for tourism, industry, and agriculture. Given the region’s dependence on tourism, the train will accelerate the growth, as well as the social and environmental impacts of tourism in the region. Globally, the tourism industry has resulted in inequitable social and environmental impacts for the local communities and there is concern that this new Maya Train Project will serve to accelerate uneven development in the region. This project focused on the coastal tourist city of Puerto …


Analytical Models For Traffic Congestion And Accident Analysis, Hongrui Liu, Rahul Ramachandra Shetty Nov 2021

Analytical Models For Traffic Congestion And Accident Analysis, Hongrui Liu, Rahul Ramachandra Shetty

Mineta Transportation Institute

In the US, over 38,000 people die in road crashes each year, and 2.35 million are injured or disabled, according to the statistics report from the Association for Safe International Road Travel (ASIRT) in 2020. In addition, traffic congestion keeping Americans stuck on the road wastes millions of hours and billions of dollars each year. Using statistical techniques and machine learning algorithms, this research developed accurate predictive models for traffic congestion and road accidents to increase understanding of the complex causes of these challenging issues. The research used US Accidents data consisting of 49 variables describing 4.2 million accident records …


Greenhouse Gas Inventory Of Transportation And Driving Habits At Gettysburg College, Flavia Soctto D'Antuono, Megan G. Wojnar Oct 2021

Greenhouse Gas Inventory Of Transportation And Driving Habits At Gettysburg College, Flavia Soctto D'Antuono, Megan G. Wojnar

Student Publications

By tracking the overall emissions put out by a college campus, mitigation strategies can be researched to lower total emissions. This study utilized a survey for both the student body and faculty and staff members at Gettysburg College in Gettysburg, Pennsylvania. This survey allowed this study to answer three research questions; what is the total number of Scope 3 emissions at Gettysburg College, how do these findings compare to findings from 2009 and the 2016 STARS report for Gettysburg College, and if any potential mitigation strategies are welcomed by the campus community. This study examined five major driving related emission …


Gp3: Gaussian Process Path Planning For Reliable Shortest Path In Transportation Networks, Hongliang Guo, Xuejie Hou, Zhiguang Cao, Jie Zhang Aug 2021

Gp3: Gaussian Process Path Planning For Reliable Shortest Path In Transportation Networks, Hongliang Guo, Xuejie Hou, Zhiguang Cao, Jie Zhang

Research Collection School Of Computing and Information Systems

This paper investigates the reliable shortest path (RSP) problem in Gaussian process (GP) regulated transportation networks. Specifically, the RSP problem that we are targeting at is to minimize the (weighted) linear combination of mean and standard deviation of the path's travel time. With the reasonable assumption that the travel times of the underlying transportation network follow a multi-variate Gaussian distribution, we propose a Gaussian process path planning (GP3) algorithm to calculate the a priori optimal path as the RSP solution. With a series of equivalent RSP problem transformations, we are able to reach a polynomial time complexity algorithm with guaranteed …


Effects Of The Transportation And Climate Initiative On The Maine Economy: An Analysis Of Cap-And-Invest And Its Heterogeneous Impacts On Rural And Urban Households, William L. Somes May 2021

Effects Of The Transportation And Climate Initiative On The Maine Economy: An Analysis Of Cap-And-Invest And Its Heterogeneous Impacts On Rural And Urban Households, William L. Somes

Honors College

In December 2020, a memorandum of understanding (MOU) was released by the Transportation and Climate Initiative Program (TCI-P), a collaboration of 13 jurisdictions in the New England and Mid-Atlantic regions of the United States. Modeled on the Regional Greenhouse Gas Initiative (RGGI), the TCI-P follows a cap-and-invest framework to reduce emissions from the transportation sector by 26% from 2022 to 2032. Since the TCI-P is expected to raise the price of gasoline by 5¢ to 9¢ per gallon, there has been concern that some populations may be disproportionately affected. The present research studies the potential heterogeneous impacts of the TCI-P …


A Smarter Way To Manage Mass Transit In A Smart City: Rail Network Management At Singapore’S Land Transport Authority, Steven M. Miller, Thomas H. Davenport May 2021

A Smarter Way To Manage Mass Transit In A Smart City: Rail Network Management At Singapore’S Land Transport Authority, Steven M. Miller, Thomas H. Davenport

Research Collection School Of Computing and Information Systems

There is no widely agreed upon definition of a supposed “Smart City.” Yet, when you see city employees — in this case city-state employees — working in what are obviously smarter ways, “you know it when you see it.” One such example of a smarter way to work in a smart city setting is the way that employees of the Land Transport Authority (LTA) in Singapore are using a new generation of data driven, AI-enabled support systems to manage the city’s urban rail network. We spoke to LTA officers Kong Wai, Ho (Director of Integrated Operations and Planning) and Chris …


Estimated 2020 Co2 Emission Reductions In Virginia’S Transportation Sector From Covid-19, Eden E. Rakes, Pamela R. Grothe, Jeremy S. Hoffman Feb 2021

Estimated 2020 Co2 Emission Reductions In Virginia’S Transportation Sector From Covid-19, Eden E. Rakes, Pamela R. Grothe, Jeremy S. Hoffman

Virginia Journal of Science

The initial lockdown phase of the COVID-19 pandemic presented an unfortunate opportunity to observe how abrupt, large-scale changes in traffic volume can reduce greenhouse gas emissions. This study explores how carbon dioxide (CO2) emissions from Virginia’s transportation sector may have been affected by the changes in activity stemming from COVID-19 to inform more carbon-neutral policies as the state recovers from the economic downfall. Emission savings were calculated by multiplying the percent change from 2019 to 2020 in traffic volume from the Virginia Department of Transportation with the business-as-usual 2020 U.S. Environmental Protection Agency estimate of CO2 emissions …


Using Reinforcement Learning To Minimize The Probability Of Delay Occurrence In Transportation, Zhiguang Cao, Hongliang Guo, Wen Song, Kaizhou Gao, Zhengghua Chen, Le Zhang, Xuexi Zhang Mar 2020

Using Reinforcement Learning To Minimize The Probability Of Delay Occurrence In Transportation, Zhiguang Cao, Hongliang Guo, Wen Song, Kaizhou Gao, Zhengghua Chen, Le Zhang, Xuexi Zhang

Research Collection School Of Computing and Information Systems

Reducing traffic delay is of crucial importance for the development of sustainable transportation systems, which is a challenging task in the studies of stochastic shortest path (SSP) problem. Existing methods based on the probability tail model to solve the SSP problem, seek for the path that minimizes the probability of delay occurrence, which is equal to maximizing the probability of reaching the destination before a deadline (i.e., arriving on time). However, they suffer from low accuracy or high computational cost. Therefore, we design a novel and practical Q-learning approach where the converged Q-values have the practical meaning as the actual …


Ai Gets Real At Singapore's Changi Airport (Part 1), Steve Lee, Steven M. Miller May 2019

Ai Gets Real At Singapore's Changi Airport (Part 1), Steve Lee, Steven M. Miller

Asian Management Insights

Ranked as the best airport for seven consecutive years, Singapore’s Changi Airport is lauded the world over for the efficient, safe, pleasurable and seamless service it offers the millions of passengers that pass through its facilities annually. Much of Changi Airport’s success can be attributed to the organisation’s customer-oriented business focus and deeply embedded culture of service excellence, combined with a host of advanced technologies operating invisibly in the background. The framework for this technology enablement is Changi Airport Group’s (CAG’s) SMART Airport Vision—an enterprise-wide approach to connective technologies that leverages sensors, data fusion, data analytics, and artificial intelligence (AI), …


Distilling Managerial Insights And Lessons From Ai Projects At Singapore's Changi Airport (Part 2), Steve Lee, Steven M. Miller May 2019

Distilling Managerial Insights And Lessons From Ai Projects At Singapore's Changi Airport (Part 2), Steve Lee, Steven M. Miller

Asian Management Insights

Since 2017, Changi Airport group (CAG) has initiated a host of pilot projects that use connective and intelligent technologies to enable its move towards digital transformation and SMART Airport Vision. This has resulted in a first wave of deployment of AI and Machine Learning-enabled applications across various functions that can better sense, analyse, predict, and interact with people.


Latent Choice Models To Account For Misclassification Errors In Discrete Transportation Data, Lacramioara Elena Balan Apr 2019

Latent Choice Models To Account For Misclassification Errors In Discrete Transportation Data, Lacramioara Elena Balan

Civil & Environmental Engineering Theses & Dissertations

One of the most fundamental tasks when it comes to analyzing data using statistical methods is to understand the relationship between the explanatory variables and the outcome. Misclassification of explanatory variables is a common risk when using statistical modeling techniques. In this dissertation, we define ‘misclassification,’ as a response that is reported or recorded in the wrong category; for example, a variable is registered as a one when it should have the value zero. Misclassification can easily happen in any data; for example, in an interview setting where the respondent misunderstands the question or the interviewer checks the wrong box. …


Supply Chain Managers' Reverse Logistics Strategies To Control Cost Through Risk Mitigation, Lawrence A. Reeves Jan 2019

Supply Chain Managers' Reverse Logistics Strategies To Control Cost Through Risk Mitigation, Lawrence A. Reeves

Walden Dissertations and Doctoral Studies

Supply chain managers in the food and beverage industry face significant challenges regarding the use of effective reverse logistics strategies to reduce supply chain disruptions, control risk, and reduce costs. Through the lens of resource dependence theory, the purpose of this multiple case study was to explore reverse logistics strategies used by supply chain managers in the United States to control cost through risk mitigation. Participants in this study included 5 supply chain managers in the food and beverage distribution industry in the state of Georgia who implemented successful reverse logistics strategies to control cost through risk mitigation. Data were …


Science, Advocacy, Policy, Planning: Tools For Advancing Transportation Equity, Garrett S. Mcallister May 2018

Science, Advocacy, Policy, Planning: Tools For Advancing Transportation Equity, Garrett S. Mcallister

Graduate Student Portfolios, Professional Papers, and Capstone Projects

The theme of this portfolio is how different tools and approaches can be used for advancing transportation equity. Broadly defined, transportation equity is about fairness in transportation. There are a number of ways this fairness can be assessed. The most common way to assess transportation equity is by looking at the fairness of outcomes, distributed geographically, socially, or even by mode of transportation. Equity can also be defined by the fairness of processes. The first half of the portfolio illustrates some of the problems with the current transportation system and how it is unhealthy (Piece 1) and unjust (Piece 2). …


Proactive And Reactive Strategies To Handle Surges In Urban Crowds, Jiali Du May 2017

Proactive And Reactive Strategies To Handle Surges In Urban Crowds, Jiali Du

Dissertations and Theses Collection

Most urban infrastructures are built to cater a planned capacity, yet surges in usage do happen in times (can be either expected or unexpected), and this has long been a major challenge for urban planner. In this thesis, I propose to study approaches handle surges in urban crowd movement. In particular, the surges in demand studied are limited to situations where a large crowd of commuters/visitors gather in a small vicinity, and I am concerned with their movements both within the vicinity and out of the vicinity (the egress from the vicinity). Significant crowd build-ups and congestions can be observed …


Vulnerabilities, Attacks, And Countermeasures In Balise-Based Train Control Systems, Yongdong Wu, Jian Weng, Zhe Tang, Xin Li, Robert H. Deng Apr 2017

Vulnerabilities, Attacks, And Countermeasures In Balise-Based Train Control Systems, Yongdong Wu, Jian Weng, Zhe Tang, Xin Li, Robert H. Deng

Research Collection School Of Computing and Information Systems

In modern rail transport systems, balises are widely used to exchange track-train information via air-gap interface. In this paper, we first present the vulnerabilities on the standard balise air-gap interface, and then conduct vulnerability simulations using the system parameters that were specified in the European Train Control System. The simulation results show that the vulnerabilities can be exploited to launch effective and practical attacks, which could lead to catastrophic consequences, such as train derailment or collision. To mitigate the vulnerabilities and attacks, we propose to implement a challenge-response authentication process in the air-gap interface in the existing transport infrastructure.


Grab Taxi: Navigating New Frontiers, Mei Lin, Christopher Dula Nov 2016

Grab Taxi: Navigating New Frontiers, Mei Lin, Christopher Dula

Research Collection School Of Computing and Information Systems

In mid-2016, Anthony Tan, the CEO of Grab, an on-demand transportation-app company serving Southeast Asia, was locked in a high stakes struggle to win the hearts and minds of drivers, passengers and regulators alike. Valued at an estimated US$1.5 billion, Grab (known among consumers as ‘GrabTaxi’) had become one of Asia’s most successful start-ups.


Transportation Asset Exposure, Adaptation Alternatives, And Infrastructure Resilience: Steering Committee Project Appraisal, Bahar Barami May 2016

Transportation Asset Exposure, Adaptation Alternatives, And Infrastructure Resilience: Steering Committee Project Appraisal, Bahar Barami

May 18, 2016: The Economic Impacts of Sea-Level Rise in Hampton Roads

PDF of powerpoint presentation at the workshop "The Economic Impacts of Sea-Level Rise in Hampton Roads: An Appraisal of the Projects Underway" on May 18, 2016 at the Virginia Modeling and Simulation Center, 1030 University Blvd, Suffolk, VA 23435


Economic And Traffic Impacts Following The Installation Of New Bicycle Facilities: A Denver Case Study, Stephen Antonio Rijo Jan 2015

Economic And Traffic Impacts Following The Installation Of New Bicycle Facilities: A Denver Case Study, Stephen Antonio Rijo

Electronic Theses and Dissertations

America is currently experiencing a unique departure from the historical vehicle miles traveled (VMT) trend, often referred to as "peak travel." Decreasing VMT numbers suggest that the US is currently experiencing an unprecedented change in the way individuals utilize transportation systems. The following research calls on a need to understand the importance of improving alternative transportation infrastructure, namely cycling facilities, and how this impacts local businesses and their communities. This research informs the overarching question, "What are the economic and traffic impacts of cycling facilities?" A mixed methods analysis of retail sales tax, traffic count, and RTD transit access data …


Time-Series Data Mining In Transportation: A Case Study On Singapore Public Train Commuter Travel Patterns, Roy Ka Wei Lee, Tin Seong Kam Oct 2014

Time-Series Data Mining In Transportation: A Case Study On Singapore Public Train Commuter Travel Patterns, Roy Ka Wei Lee, Tin Seong Kam

Research Collection School Of Computing and Information Systems

The adoption of smart cards technologies and automated data collection systems (ADCS) in transportation domain had provided public transport planners opportunities to amass a huge and continuously increasing amount of time-series data about the behaviors and travel patterns of commuters. However the explosive growth of temporal related databases has far outpaced the transport planners’ ability to interpret these data using conventional statistical techniques, creating an urgent need for new techniques to support the analyst in transforming the data into actionable information and knowledge. This research study thus explores and discusses the potential use of time-series data mining, a relatively new …


Time-Series Data Mining In Transportation: A Case Study On Singapore Public Train Commuter Travel Patterns, Tin Seong Kam, Roy Ka Wei Lee Mar 2014

Time-Series Data Mining In Transportation: A Case Study On Singapore Public Train Commuter Travel Patterns, Tin Seong Kam, Roy Ka Wei Lee

Research Collection School Of Computing and Information Systems

The adoption of smart cards technologies and automated data collection systems (ADCS) in transportation domain had provided public transport planners opportunities to amass a huge and continuously increasing amount of time-series data about the behaviors and travel patterns of commuters. However the explosive growth of temporal related databases has far outpaced the transport planners’ ability to interpret these data using conventional statistical techniques, creating an urgent need for new techniques to support the analyst in transforming the data into actionable information and knowledge. This research study thus explores and discusses the potential use of time-series data mining, a relatively new …


Estimation Of Performance Indices For The Planning Of Sustainable Transportation Systems, Alexander Paz, Pankaj Maheshwari, Pushkin Kachroo, Sajjad Ahmad Jan 2013

Estimation Of Performance Indices For The Planning Of Sustainable Transportation Systems, Alexander Paz, Pankaj Maheshwari, Pushkin Kachroo, Sajjad Ahmad

Civil and Environmental Engineering and Construction Faculty Research

In the context of sustainable transportation systems, previous studies have either focused only on the transportation system or have not used a methodology that enables the treatment of incomplete, vague, and qualitative information associated with the available data. This study proposes a system of systems (SOS) and a fuzzy logic modeling approach. The SOS includes the Transportation, Activity, and Environment systems. The fuzzy logic modeling approach enables the treatment of the vagueness associated with some of the relevant data. Performance Indices (PIs) are computed for each system using a number of performance measures. The PIs illustrate the aggregated performance of …


Agenda: 2012 Energy Justice Conference And Technology Exposition, University Of Colorado Boulder. Center For Energy & Environmental Security, University Of Colorado Boulder. Colorado European Union Center Of Excellence, University Of Colorado Boulder. Presidents Leadership Institute Sep 2012

Agenda: 2012 Energy Justice Conference And Technology Exposition, University Of Colorado Boulder. Center For Energy & Environmental Security, University Of Colorado Boulder. Colorado European Union Center Of Excellence, University Of Colorado Boulder. Presidents Leadership Institute

2012 Energy Justice Conference and Technology Exposition (September 17-18)

Co-sponsored with the Colorado European Union Center of Excellence and the Presidents Leadership Institute at the University of Colorado Boulder.

The ability to harness energy is fundamental to economic and social development. Worldwide, almost 3 billion people have little or no access to beneficial energy resources for cooking, heating, water sanitation, illumination, transportation, or basic mechanical needs. Energy poverty exacerbates ill health and economic hardship, and reduces educational opportunities, particularly for women and children. Specifically, access to efficient and affordable energy services is a prerequisite for achieving the Millennium Development Goal (MDG) relating to poverty eradication.

In response, the UN …


A Multimodal Freight Collaborative Hub Location And Network Design Problem, Jiri Tylich Jan 2012

A Multimodal Freight Collaborative Hub Location And Network Design Problem, Jiri Tylich

Open Access Theses & Dissertations

The study presents an analytical framework to explore the rail-road collaborative paradigm.

New collaborative technologies have been developed in recent years and they offer a potential solutions and opportunities for collaboration among all modes of transportation. The most progressive technologies that could fulfill the gap in rail-road collaborative paradigm are identified and presented in this research.

The research deals with current state and possible development of collaboration of rail and highway modes of transportation, referred to as rail-road collaboration. Multimodal transportation is the shipment of goods in a single transportation unit. The longest part of the route takes place by …


Green Transportation For A Green Earth, Petros J. Katsioloudis, Mildred V. Jones Jan 2012

Green Transportation For A Green Earth, Petros J. Katsioloudis, Mildred V. Jones

STEMPS Faculty Publications

Transportation is one of the biggest contributors to the destruction of the environment. Results from environmental research and pursuant governmental regulations are changing the way companies do business and how transportation systems address the future. The Environmental Protection Agency (EPA) has been at the forefront in leading environmental research and instituting policies and regulations to fight the issues impacting the environment. The transportation industry and consumers alike are concerned about the environment, energy resources, efficiencies, and economics. In this article, the authors suggest that it is vital that people promote the protection of the environment and strengthen the laws that …


Statistical Analysis Of Fatalities Due To Vehicle Accidents In Las Vegas, Nv, Annabelle Marie Mathis Aug 2011

Statistical Analysis Of Fatalities Due To Vehicle Accidents In Las Vegas, Nv, Annabelle Marie Mathis

UNLV Theses, Dissertations, Professional Papers, and Capstones

The goal of this thesis is to investigate factors that affect the odds of having a fatality in a vehicle collision. We will be looking at characteristics of the driver that caused the accident (age, gender, behavior, actions, influences, and seat belt worn), the characteristics of the vehicle the driver drove (type of vehicle, and air bag deployment), the characteristics of the environment in which the accident occurred (weather, road condition, lighting, time of day, the day of the week, and month of the year), the characteristics of the crash (direction of accident and how many vehicles were involved), and …


Modeling Decision Making Related To Incident Delays During Hurricane Evacuations, Robert Michael Robinson Jan 2010

Modeling Decision Making Related To Incident Delays During Hurricane Evacuations, Robert Michael Robinson

Computational Modeling & Simulation Engineering Theses & Dissertations

Successful evacuations from metropolitan areas require optimizing the transportation network, monitoring conditions, and adapting to changes. Evacuation plans seek to maximize the city's ability to evacuate traffic to flee the endangered region, but once an evacuation begins, real time events degrade even the best plans.

To better understand behavioral responses made during a hurricane evacuation, a survey of potential evacuees obtained data on demographics, driving characteristics, and the traffic information considered prior to and during an evacuation. Analysis showed significant levels of correlation between demographic factors (e.g., gender, age, social class, etc.) and self-assessed driver characteristics, but limited correlation with …


Slides: Taking The Long View: Doing Something About Climate Change, David Getches, Susan Avery, Maggie Fox, Roger Pielke Jun 2006

Slides: Taking The Long View: Doing Something About Climate Change, David Getches, Susan Avery, Maggie Fox, Roger Pielke

Climate Change and the Future of the American West: Exploring the Legal and Policy Dimensions (Summer Conference, June 7-9)

Presenter: Maggie Fox, President, America Votes, Boulder, CO.

Presenter: Susan Avery, Interim Provost and Executive Vice-Chancellor for Academic Affairs, University of Colorado.

Presenter: Roger Pielke, Jr., Professor, Environmental Studies, Center for Science and Technology Policy Research, University of Colorado.

4 slides.