Engineering Commons^™

Beneficial Mutations For Carotenoid Production Identified From Laboratory-Evolved Saccharomyces Cerevisiae, Avinash Godara, Maria Alejandra Gomez Rodriguez, Joshua Weatherston, George Peabody, Hung-Jen Wu, Katy Kao

Faculty Publications

Adaptive laboratory evolution (ALE) is a powerful tool used to increase strain fitness in the presence of environmental stressors. If production and strain fitness can be coupled, ALE can be used to increase product formation. In earlier work, carotenoids hyperproducing mutants were obtained using an ALE strategy. Here, de novo mutations were identified in hyperproducers, and reconstructed mutants were explored to determine the exact impact of each mutation on production and tolerance. A single mutation in YMRCTy1-3 conferred increased carotenoid production, and when combined with other beneficial mutations led to further increased β-carotene production. Findings also suggest that the ALE …

Green Up Pavement Rehabilitation Design Tool, Dragos Andrei, Robert E. Kochan, Jose H. Perez

Mineta Transportation Institute Publications

While designers produce pavement rehabilitation recommendations every day, for projects of all sizes, most designers have little information on the environmental impact of their recommendations. This research developed a new decision tool, called the “Green Up Pavement Rehabilitation Design Tool,” to allow the comparison of different rehabilitation solutions in terms of greenhouse gas emissions and to encourage sustainable practices such as materials recycling and the use of permeable, cool, and quiet pavement surfaces. The project aligns with the major goal of California Senate Bill 1, which is “to address deferred maintenance on the state highway system and the local street …

The Potential For Using Loyalty Rewards And Incentives Programs To Encourage Transit Ridership And Regional Transportation And Land Use Integration, Christopher E. Ferrell

Mineta Transportation Institute Publications

Transit smart cards can be used as a tool for increasing transit ridership, increasing retail sales in transit-oriented developments (TODs) and eventually, increasing opportunities for retail development in TODs. Instead of providing separate loyalty rewards for each store, or chain of stores, such cards would provide loyalty rewards—in several possible forms, including free transit ride credits, cash rewards, retail purchase discounts, sweepstakes rewards—to all transit riders who patronize TOD retail businesses. Additional rewards could also be given to transit riders who live, work, and shop in TODs, and even to riders who take transit for specific shopping trips in TODs. …

Automated Measurement Of Heavy Equipment Greenhouse Gas Emission: The Case Of Road/Bridge Construction And Maintenance, Reza Akhavian

Mineta Transportation Institute Publications

Road/bridge construction and maintenance projects are major contributors to greenhouse gas (GHG) emissions such as carbon dioxide (CO2), mainly due to extensive use of heavy-duty diesel construction equipment and large-scale earthworks and earthmoving operations. Heavy equipment is a costly resource and its underutilization could result in significant budget overruns. A practical way to cut emissions is to reduce the time equipment spends doing non-value-added activities and/or idling. Recent research into the monitoring of automated equipment using sensors and Internet-of-Things (IoT) frameworks have leveraged machine learning algorithms to predict the behavior of tracked entities.

In this project, end-to-end deep learning models …

Cgste11 Mediates Cross Tolerance To Multiple Environmental Stressors In Candida Glabrata, Mian Huang, Jibran Khan, Manpreet Kaur, Julian Daniel Torres Vanega, Orlando Andres Aguilar Patiño, Anand Ramasubramanian, Katy Kao

Faculty Publications

Candida glabrata is a human commensal and an opportunistic human fungal pathogen. It is more closely related to the model yeast Saccharomyces cerevisiae than other Candida spp. Compared with S. cerevisiae, C. glabrata exhibits higher innate tolerance to various environmental stressors, including hyperthermal stress. Here we investigate the molecular mechanisms of C. glabrata adaptation to heat stress via adaptive laboratory evolution. We show that all parallel evolved populations readily adapt to hyperthermal challenge (from 47 °C to 50 °C) and exhibit convergence in evolved phenotypes with extensive cross-tolerance to various other environmental stressors such as oxidants, acids, and alcohols. Genome …

Use Of Neural Networks To Identify Safety Prevention Priorities In Agro-Manufacturing Operations Within Commercial Grain Elevators, Fatemeh Davoudi Kakhki, Steven Freeman, Gretchen Mosher

Faculty Research, Scholarly, and Creative Activity

The grain handling industry plays a significant role in U.S. agriculture by storing, distributing, and processing a variety of agricultural commodities. Commercial grain elevators are hazardous agro-manufacturing work environments where workers are prone to severe injuries, due to the nature of the activities and workplace. Safety incidents in agro-manufacturing operations generally arise from a combination of factors, rather than a single cause, therefore, research on occupational incidents must look deeper into identifying the underlying causes, through the application of advanced analyses methods. In occupational safety, it is possible to estimate and predict probability of safety risks through developing artificial neural …

Moving From Walkability? Evaluation Traditional And Merging Data Sources For Evaluating Changes In Campus-Generated Greenhouse Gas Emissions, Troy Kawahara, Bo Liu, Anurag Pande, Calvin Thigpen, Carole Turley Voulgaris

Mineta Transportation Institute Publications

Universities are increasingly committing to reduce campus-generated greenhouse gas emissions, whether voluntarily or in response to a legal mandate. As an initial step to keeping these commitments, universities need an accounting of baseline greenhouse gas emissions levels and means of monitoring changes in campus-generated greenhouse gas emissions over time. Commute-generated greenhouse gas emissions from travel to and from campus by students and employees are among the most difficult to quantify. This report examines some of the challenges associated with estimating campus-generated greenhouse gas emissions and evaluates ways to address those challenges. The purpose of this study is to identify changes …

A Framework For Integrating Transportation Into Smart Cities, Susan Shaheen, Adam Cohen, Mark K. Dowd, Richard Davis

Mineta Transportation Institute Publications

In recent years, economic, environmental, and political forces have quickly given rise to “Smart Cities” -- an array of strategies that can transform transportation in cities. Using a multi-method approach to research and develop a framework for smart cities, this study provides a framework that can be employed to:

1. Understand what a smart city is and how to replicate smart city successes;
2. The role of pilot projects, metrics, and evaluations to test, implement, and replicate strategies; and
3. Understand the role of shared micromobility, big data, and other key issues impacting communities.

This research provides recommendations for policy and professional practice …

Youth Design The Future Of Transportation For Their Community, Christian Wandeler, Steven Hart, Felipe Mercado

Mineta Transportation Institute Publications

The complexity of a globalized world, accelerating technological advances, and rapid change challenge educational systems. Around the world the call is to develop 21st century skills with a focus on career readiness, ability for lifelong learning, and collaboration skills. The development of the foundational elements of civic engagement (civic knowledge, skills, and dispositions) of children and youth is also a dominant concern for educators and policymakers. Unfortunately, not all youth have the same opportunities to develop civic self-efficacy. However, the civic empowerment engagement gap can be closed by providing underserved students with interactive and authentic civic experiences.

We strove to …

Predicting Acceptable Wait Times For Patrons At Transit Bus Stops By Time Of Day, Stephen Arhin

Mineta Transportation Institute Publications

The time spent waiting by bus patrons at bus stops is a primary measure for assessing the reliability of transit services. Uncertainty associated with waiting affects bus patrons’ perception of quality of the service provided. Consequently, this study aimed to determine patrons’ maximum and minimum acceptable wait times at bus stops in Washington, DC and to develop prediction models to provide decision-makers with additional tools for improving patronage.

The data used in this study was obtained by surveying 3,388 bus patrons at 71 selected bus stops in Washington, D.C. over an eight-month period. Data obtained from patrons included their ethnicity, …

Optical Response Of Bifeo3 Films Subjected To Uniaxial Strain, Andrew Herklotz, Stefania Rus, Changhee Sohn, Santosh Kc, Valentino Cooper, Er-Jia Guo, Thomas Ward

Faculty Publications

The impact of single-axis lattice expansion on the optical response of BiFeO3 films is examined. Low-energy He implantation is used to tailor morphotropic phases of BiFeO3 films and study changes in their optical spectra with continuously increasing lattice expansion. He ion implantation of epitaxial rhombohedral (R)- and tetragonal (T)-like BiFeO3 films induces uniaxial out-of-plane strain that, on R-like films, eventually leads to a complete R-T phase transition. This approach allows us to provide insights into the optical response of BiFeO3 films. Strain doping of T-like films leads to a significant redshift of the optical absorption spectra that is theoretically explained …

Segmentation Of Severe Occupational Incidents In Agribusiness Industries Using Latent Class Clustering, Fatemeh Davoudi Kakhki, Steven Freeman, Gretchen Mosher

Faculty Publications

One of the principle objectives in occupational safety analysis is to identify the key factors that affect the severity of an incident. To identify risk groups of occupational incidents and the factors associated with them, statistical analysis of workers’ compensation claims data is performed using latent class clustering, for the segmentation of 1031 severe occupational incidents in agribusiness industries in the Midwest region of the United States between 2008–2016. In this study, severe incidents are those with workers’ compensation costs equal to or greater than $100,000 (USD). Based on the latent class clustering results, three risk groups are identified with …

How Effective Are Toll Roads In Improving Operational Performance?, Sonu Mathew, Srinivas S. Pulugurtha

Mineta Transportation Institute Publications

The main focus of this research is to develop a systematic analytical framework and evaluate the effect of a toll road on region’s traffic using travel time and travel time reliability measures. The travel time data for the Triangle Expressway in Raleigh, North Carolina, United States was employed for the assessment process. The spatial and temporal variations in the travel time distributions on the toll road, parallel alternate route, and near-vicinity cross-streets were analyzed using various travel time reliability measures. The results indicate that the Triangle Expressway showed a positive trend in reliability over the years of its operation. The …

Use Of Logistic Regression To Identify Factors Influencing The Post-Incident State Of Occupational Injuries In Agribusiness Operations, Fatemeh Davoudi Kakhki, Steven Freeman, Gretchen Mosher

Faculty Publications

Agribusiness industries are among the most hazardous workplaces for non-fatal occupational injuries. The term “post-incident state” is used to describe the health status of an injured person when a non-fatal occupational injury has occurred, in the post-incident period when the worker returns to work, either immediately with zero days away from work (medical state) or after a disability period (disability state). An analysis of nearly 14,000 occupational incidents in agribusiness operations allowed for the classification of the post-incident state as medical or disability (77% and 23% of the cases, respectively). Due to substantial impacts of occupational incidents on labor-market outcomes, …

Tutorial: Are You My Neighbor?: Bringing Order To Neighbor Computing Problems, David Anastasiu, Huzefa Rangwala, Andrea Tagarelli

Faculty Publications

Finding nearest neighbors is an important topic that has attracted much attention over the years and has applications in many fields, such as market basket analysis, plagiarism and anomaly detection, community detection, ligand-based virtual screening, etc. As data are easier and easier to collect, finding neighbors has become a potential bottleneck in analysis pipelines. Performing pairwise comparisons given the massive datasets of today is no longer feasible. The high computational complexity of the task has led researchers to develop approximate methods, which find many but not all of the nearest neighbors. Yet, for some types of data, efficient exact solutions …

Evaluating Machine Learning Performance In Predicting Injury Severity In Agribusiness Industries, Fatemeh Davoudi Kakhki, Steven Freeman, Gretchen Mosher

Faculty Publications

Although machine learning methods have been used as an outcome prediction tool in many fields, their utilization in predicting incident outcome in occupational safety is relatively new. This study tests the performance of machine learning techniques in modeling and predicting occupational incidents severity with respect to accessible information of injured workers in agribusiness industries using workers’ compensation claims. More than 33,000 incidents within agribusiness industries in the Midwest of the United States for 2008–2016 were analyzed. The total cost of incidents was extracted and classified from workers’ compensation claims. Supervised machine learning algorithms for classification (support vector machines with linear, …

Non-Conventional Mechanism Of Ferroelectric Fatigue Via Cation Migration, Anton Ievlev, Santosh Kc, Rama Vasudevan, Yunseok Kim, Xiaoli Lu, Marin Alexe, Valentino Cooper, Sergei Kalinin, Olga Ovchinnikova

Faculty Publications

The unique properties of ferroelectric materials enable a plethora of applications, which are hindered by the phenomenon known as ferroelectric fatigue that leads to the degradation of ferroelectric properties with polarization cycling. Multiple microscopic models explaining fatigue have been suggested; however, the chemical origins remain poorly understood. Here, we utilize multimodal chemical imaging that combines atomic force microscopy with time-of-flight secondary mass spectrometry to explore the chemical phenomena associated with fatigue in PbZr0.2Ti0.8O3 (PZT) thin films. Investigations reveal that the degradation of ferroelectric properties is correlated with a local chemical change and migration of electrode ions into the PZT structure. …

Seven Hci Grand Challenges, Constantine Stephanidis, Gavriel Salvendy, Margherita Antona, Jessie Chen, Jianming Dong, Vincent Duffy, Xiaowen Fang, Cali Fidopiastis, Gino Fragomeni, Limin Fu, Yinni Guo, Don Harris, Andri Ioannou, Kyeong-Ah (Kate) Jeong, Shin'ichi Konomi, Heidi Kromker, Masaaki Kurosu, James Lewis, Aaron Marcus, Gabriele Meiselwitz, Abbas Moallem, Hirohiko Mori, Fiona Fui-Hoon Nah, Stavroula Ntoa, Pei-Luen Rau, Dylan Schmorrow, Keng Siau, Norbert Streitz, Wentao Wang, Sakae Yamamoto, Panayiotis Zaphiris, Jia Zhou

Faculty Publications

This article aims to investigate the Grand Challenges which arise in the current and emerging landscape of rapid technological evolution towards more intelligent interactive technologies, coupled with increased and widened societal needs, as well as individual and collective expectations that HCI, as a discipline, is called upon to address. A perspective oriented to humane and social values is adopted, formulating the challenges in terms of the impact of emerging intelligent interactive technologies on human life both at the individual and societal levels. Seven Grand Challenges are identified and presented in this article: Human-Technology Symbiosis; Human-Environment Interactions; Ethics, Privacy and Security; …

Analysis Of Disengagements In Semi-Autonomous Vehicles: Drivers’ Takeover Performance And Operational Implications, Francesca M. Favaro, Sky Eurich, Syeda Rizvi, Shivangi Agarwal, Sumaid Mahmood, Nazanin Nader

Mineta Transportation Institute Publications

This report analyzes the reactions of human drivers placed in simulated Autonomous Technology disengagement scenarios. The study was executed in a human-in-the-loop setting, within a high-fidelity integrated car simulator capable of handling both manual and autonomous driving. A population of 40 individuals was tested, with metrics for control takeover quantification given by: i) response times (considering inputs of steering, throttle, and braking); ii) vehicle drift from the lane centerline after takeover as well as overall (integral) drift over an S-turn curve compared to a baseline obtained in manual driving; and iii) accuracy metrics to quantify human factors associated with the …

Distribution Of Bit Patterns In Binary Sequence Generated Over Sub Extension Field, Md. Arshad Ali, Yuta Kodera, Yasuyuki Nogami, Satoshi Uehara, Robert Morelos-Zaragoza

Faculty Publications

The distribution of bit patterns is an important measure to check the randomness of a sequence. The authors of this paper observed this crucial property in a binary sequence which generated by using a primitive polynomial, trace function, and Legendre symbol defined over the sub extension field. The authors create a new dimension in the sequence generation research area by considering the sub extension field, whereas all our previous works are focused in the prime field. In terms of the distribution of bit patterns property, this research work has notable outcomes more specifically the binary sequence (defined over the sub …

On The Road To Flipping, Raji Lukkoor

Faculty Publications

The poster presentation will address the following topics: experience taking the Flip Workshop, How the instructor went from a “no” to a “yes” on considering implementing the flip, the frenzied list of activities that helped set up the framework for a mini-flip in approximately a week’s time, the actual development of content in under 4 weeks, and the role played by my support network.

Progress On Longitudinal Study Of The Impact Of Growth Mindset And Belonging Interventions In A Freshman Engineering Class, Jinny Rhee, Camille Johnson

Faculty Publications

Growth mindset and belonging interventions have shown to be effective in increasing retention and performance in some K-12 and postsecondary populations. These interventions hold the promise of cost-effective and scalable interventions that may be able to boost retention and graduation rates, and close the achievement gap that often exists between underrepresented (URM) students and non-URMs.A study of the impact of growth mindset and belonging interventions was designed and implemented in the 2015-2016 academic year in an Introduction to Engineering Course typically taken in the freshman year of all engineering and technology programs at a large comprehensive public university. The interventions …

Influence Propagation For Social Graph-Based Recommendations, Avni Gulati, Magdalini Eirinaki

Faculty Publications

Social networking is an inevitable behavior of humans living in a society. In recent years, and with the rise of online social networks, personalized recommendations that leverage the social aspect have become a very intriguing domain for researchers. In this work, we explore how influence propagation and the decay in the cascading effect of influence from influential users can be leveraged to generate social graph-based recommendations. Understanding how influence propagates within a social network is itself a challenging problem. Few researchers have considered influence propagation and even fewer have considered decay in the cascading effect of influence in a social …

The Rapid Deployments To Wildfires Experiment (Radfire): Observations From The Fire Zone, Craig Clements, Neil Lareau, David Kingsmill, Carrie Bowers, Christopher Camacho, Richard Bagley, Braniff Davis

Faculty Publications, Meteorology and Climate Science

The Rapid Deployments to Wildfires Experiment (RaDFIRE) was a meteorological field campaign aimed at observing fire–atmosphere interactions during active wildfires. Using a rapidly deployable scanning Doppler lidar, airborne Doppler radar, and a suite of other instruments, the field campaign sampled 21 wildfires from 2013 to 2016 in the western United States. Observations include rotating convective plumes, plume interactions with stable layers and multilayered smoke detrainment, convective plume entrainment processes, smoke-induced density currents, and aircraft in situ observations of developing pyrocumulus. Collectively, these RaDFIRE observations highlight the range of meteorological phenomena associated with wildfires, especially plume dynamics, and will provide a …

Effects Of Seawater On Carotenoid Production And Lipid Content Of Engineered Saccharomyces Cerevisiae, Yuqi Guo, Shangxian Xie, Joshua Yuan, Katy Kao

Faculty Publications

The use of seawater in fermentation can potentially reduce the freshwater burden in the bio-based production of chemicals and fuels. We previously developed a Saccharomyces cerevisiae carotenoids hyperproducer SM14 capable of accumulating 18 mg g−1 DCW (DCW: dry cell weight) of β-carotene in rich media (YPD). In this work, the impacts of seawater on the carotenoid production of SM14 were investigated. When using nutrient-reduced media (0.1× YNB) in freshwater the β-carotene production of SM14 was 6.51 ± 0.37 mg g−1 DCW; however in synthetic seawater, the production was increased to 8.67 ± 0.62 mg g−1 DCW. We found that this …