A Transfer Learning-Based Framework for Enriching National Household Travel Survey Data with Attitudinal Variables

(Georgia Institute of Technology, 2022-06) Malokin, Aliaksandr ; Mokhtarian, Patricia L. ; Circella, Giovanni

Often in practice, the problem of unavailability of specific desired knowledge within one (“target”) dataset arises. However, if this knowledge can be extracted from a different (“source”) dataset and transferred between the datasets, this could increase the value of the target dataset at relatively minimal cost. The goal of this paper is to evaluate approaches to informing one dataset with knowledge from another and to evaluate the performance of the knowledge transferred into the target dataset. We use the 2009 National Household Travel Survey as the target dataset. The missing knowledge is transportation-related attitudes, whose inclusion could greatly improve travel behavior models. Our source dataset is obtained from the 2011–12 Multitasking Survey of Northern California Commuters. To achieve the goal, the set of common variables was first augmented with a large number of built-environment attributes. Then, after applying machine-learning methods, pro-transit, pro-active transportation, and pro-density attitudinal factor scores were predicted with the greatest precision; correlations of the predicted and observed scores were 0.564, 0.538, and 0.571, respectively. The performance of the transferred attitudes was measured by estimating linear regression models of vehicle ownership. The results showed that in the source dataset the observed attitudes account for an 8.0% model lift (improvement in goodness of fit), while in the target dataset the predicted attitudes account for a 1.2–5.4% model lift. Although these initial results are modest, we believe they show substantial promise, and the process has identified a number of opportunities for improvement and further research.
Analysis of the Georgia Add-on to the 2016-2017 National Household Travel Survey

(Georgia Institute of Technology, 2021-08) Kash, Gwen ; Mokhtarian, Patricia L. ; Circella, Giovanni

Through an extensive analysis of the Georgia subsample of the 2016–2017 National Household Travel Survey, this report provides an in-depth snapshot of the travel behavior of Georgians of all ages. It documents differences in travel needs and behavior by region and between demographic groups, focuses on measurement challenges and improved techniques, and identifies areas where future data collection is needed. In addition to an overview of key travel trends in the state, the report includes chapters on work travel; work flexibility (teleworking and flexible scheduling); new technologies and services, including alternative-fuel vehicles, shared mobility, and online shopping; social inclusion and equity; nonmotorized and access/egress travel; and travel for its own sake.
The Challenges in Modeling and Simulation of Fluoride-Salt-Cooled High-Temperature Reactors

(Georgia Institute of Technology, 2017-09-21) Rahnema, Farzad ; Petrovic, Bojan ; Singh, Preet ; Burke, Paul ; Zhang, Dingkang ; Noorani, Hemin ; Sun, Xiaodong ; Yoder, Graydon ; Tsvetkov, Pavel ; Zhang, Jinsuo ; Ilas, Dan

Accurate modeling and simulation (M&S) methods and tools are necessary to support design, analysis, and licensing of any reactor. This is one of the challenges that must be addressed for deployment of fluoride-salt-cooled high-temperature reactors (FHRs), as current M&S tools are insufficient due to unique phenomena associated with FHR operation including multiple heterogeneity in the reactor core, potentially large uncertainties in some of the fundamental cross section data for key reactor components, and others. FHRs offer benefits that include improved safety, proliferation-resistant waste, and improved thermodynamic efficiency due to higher operating temperatures. However, before these reactors can be deployed, several key technologies need to be developed further. In 2015, the U.S. Department of Energy initiated two university-led Integrated Research Projects (IRP) to address challenges associated with several of these technologies, one led by Georgia Tech (GT), and one led by the Massachusetts Institute of Technology (MIT). To address the M&S challenge, the GT-led IRP organized several PIRT exercises to identify fundamental, underlying issues with FHR modeling. Additionally, the two IRP teams jointly organized an FHR M&S Workshop to identify gaps in current M&S tools.
Monthly Maps of SMAP L2 Version 4 Soil Moisture Retrievals over Contiguous United States in 2016: Data Sample Size Under Various Quality Flags

(Georgia Institute of Technology, 2017-05-07) Lin, Liao-Fan ; Bras, Rafael L.

This document presents the data sample size of the SMAP L2 Version 4 soil moisture retrievals for each month during 2016 and the percentages of the soil moisture data within some quality control limits defined by NASA. The soil moisture retrievals of each 36-km grid cell are associated by NASA to a surface condition and retrieval quality flag. Each half orbit was obtained from https://nsidc.org/data/SPL2SMP/versions/4. There are 11 surface conditions defined in the SMAP data: static water, radar-derived water, coastal proximity, urban area, precipitation, snow, permanent ice, frozen ground from SMAP radiometer-derived freeze/thaw state, frozen ground from GMAO TSURF model, mountainous terrain, and dense vegetation. For each surface condition, a lower threshold T1 and a higher threshold T2 are defined. Only data with all surface conditions under the T1 threshold are flagged as high quality. In this document, we use three variables (i.e.,soil_moisture, surface_flag, and retrieval_qual_flag) from each data file to illustrate the distribution and quality of the data.
Phenomena Identification and Ranking Tables (PIRTs) Report for Material Selection and Possible Material Degradation Mechanisms in FHR

(Georgia Institute of Technology, 2017-04-16) Singh, Preet M. ; Chan, Kevin ; Rahnema, Farzad

Phenomena Identification and Ranking Table (PIRT) report for metallic materials use in Fluoride High-Temperature Reactors (FHRs)
Phenomena Identification and Ranking Tables (PIRT) Report for Fluoride High-Temperature Reactor (FHR) Neutronics

(Georgia Institute of Technology, 2016-08-04) Rahnema, Farzad ; Edgar, Chris ; Zhang, Dingkang ; Petrovic, Bojan

Ranking and identification of the phenomena presented by FHRs relating to the verification and validation of neutronics tools
The Current Status of the Tools for Modeling and Simulation of Advanced High Temperature Reactor Neutronics Analysis

(Georgia Institute of Technology, 2015-12) Rahnema, Farzad ; Petrovic, Bojan ; Edgar, Christopher ; Zhang, Dingkang ; Avigni, Pietro ; Huang, Michael ; Terlizzi, Stefano

A current status of the tools for modeling and simulation of Advanced High Temperature Reactor neutronics is provided.
Workshop Report: "Risks and Policies of Hydraulic Fracturing: Assessment and Deliberation", Georgia Tech, November 13-14, 2014

(Georgia Institute of Technology, 2014-11) Arson, Chloé ; Kirkman, Robert ; Stewart, Lauren K.

Report of the workshop: Risks and Policies of Hydraulic Fracturing: Assessment and Deliberation, held at Georgia Tech, November 2014. Report includes the following: 1. Workshop program 2. Communication: \The Fracking Debate in Europe", Dr. Terry Engelder, Professor, Department of Geosciences, Pennsylvania State University 3. Presentation:\State Review of Oil & Natural Gas Environmental Regulations, Inc." Mr. Ryan Steadley, executive director, Stronger Inc. 4. Presentation:\Conveying the Science of Risk - Evolving Perceptions Within Non-Technical Audiences", Mr. Thomas Murphy, Director of Penn State Marcellus Center for Outreach and Research 5. Presentation: \Hydraulic Fracturing: An engineering perspective on modeling issues", Mr. Hao Xu (Ph.D. student), Ms. Amanda Francis (undergraduate research assistant), Dr. Chloé Arson (Assistant Professor), School of Civil & Environmental Engineering, Georgia Institute of Technology 6. Presentation: \Acceptable Risk and the Policy Context of Hydraulic Fracturing", Dr. Robert Kirkman, Associate Professor, School of Public Policy, Georgia Institute of Technology 7. Abstract presented at the 2015 Annual International Conference of the Association of Practical and Professional Ethics: \An Integrative Approach to the Ethics of Hydraulic Fracturing: A Report on Work in Progress", Dr. Robert Kirkman, Ms. Rebecca Harris, Ms. Amanda Francis, Mr. Hao Xu, Dr. Chloé Arson, Dr. Lauren Stewart, Georgia Institute of Technology
Exploration of the energy and thermal behaviors of emerging architectures

(Georgia Institute of Technology, 2014-09-30) Yalamanchili, Sudhakar ; Kim, Hyesoon
Book of Abstracts Report from: International Workshop on Education of Future Geotechnical Engineers in Response to Emerging Multi-scale Soil-Environment Problems

(Georgia Institute of Technology, 2014-09) Arson, Chloé ; Buscarnera, Giuseppe

Book of abstracts compiled by over 40 participants, as part of a workshop organized by Principal Investigators Chloé Arson and Giuseppe Buscarnera, under NSF Grant CMMI-1443990. The workshop addressed the new skill set needed by Geotechnical Engineers to solve the multi-scale, multi-physics problems faced by modern technology. New research areas such as solid/fluid transition from the grain to the landslide; geological waste storage from micro-cracks to fractured reservoirs; bio-engineered geomerials from natural bacteria to designed structures; energy piles from soil properties to geotechnical performance; geotechnical earthquake engineering: from ground motion to structural safety all require a broader range of knowledge than previously provided in the typical Geotechnical Engineering course of study. This International Workshop aims to identify key challenges for the education of new generations of geotechnical engineers, focusing on undergraduate education. This book of abstracts was one of the outcomes of this workshop, for articles to be submitted for a special issue in the journal ASCE Journal of Professional Issues in Engineering Education and Practice.