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Articles 1 - 30 of 69
Full-Text Articles in Human Ecology
The Shocklet Transform: A Decomposition Method For The Identification Of Local, Mechanism-Driven Dynamics In Sociotechnical Time Series, David Rushing Dewhurst, Thayer Alshaabi, Dilan Kiley, Michael V. Arnold, Joshua R. Minot, Christopher M. Danforth, Peter Sheridan Dodds
The Shocklet Transform: A Decomposition Method For The Identification Of Local, Mechanism-Driven Dynamics In Sociotechnical Time Series, David Rushing Dewhurst, Thayer Alshaabi, Dilan Kiley, Michael V. Arnold, Joshua R. Minot, Christopher M. Danforth, Peter Sheridan Dodds
College of Engineering and Mathematical Sciences Faculty Publications
We introduce a qualitative, shape-based, timescale-independent time-domain transform used to extract local dynamics from sociotechnical time series—termed the Discrete Shocklet Transform (DST)—and an associated similarity search routine, the Shocklet Transform And Ranking (STAR) algorithm, that indicates time windows during which panels of time series display qualitatively-similar anomalous behavior. After distinguishing our algorithms from other methods used in anomaly detection and time series similarity search, such as the matrix profile, seasonal-hybrid ESD, and discrete wavelet transform-based procedures, we demonstrate the DST’s ability to identify mechanism-driven dynamics at a wide range of timescales and its relative insensitivity to functional parameterization. As an …
Chimera States And Seizures In A Mouse Neuronal Model, Henry M. Mitchell, Peter Sheridan Dodds, J. Matthew Mahoney, Christopher M. Danforth
Chimera States And Seizures In A Mouse Neuronal Model, Henry M. Mitchell, Peter Sheridan Dodds, J. Matthew Mahoney, Christopher M. Danforth
College of Engineering and Mathematical Sciences Faculty Publications
Chimera states - the coexistence of synchrony and asynchrony in a nonlocally-coupled network of identical oscillators - are often used as a model framework for epileptic seizures. Here, we explore the dynamics of chimera states in a network of modified Hindmarsh-Rose neurons, configured to reflect the graph of the mesoscale mouse connectome. Our model produces superficially epileptiform activity converging on persistent chimera states in a large region of a two-parameter space governing connections (a) between subcortices within a cortex and (b) between cortices. Our findings contribute to a growing body of literature suggesting mathematical models can qualitatively reproduce epileptic seizure …
Modeling The Influence Of Public Risk Perceptions On The Adoption Of Green Stormwater Infrastructure: An Application Of Bayesian Belief Networks Versus Logistic Regressions On A Statewide Survey Of Households In Vermont, Qing Ren, Asim Zia, Donna M. Rizzo, Nancy Mathews
Modeling The Influence Of Public Risk Perceptions On The Adoption Of Green Stormwater Infrastructure: An Application Of Bayesian Belief Networks Versus Logistic Regressions On A Statewide Survey Of Households In Vermont, Qing Ren, Asim Zia, Donna M. Rizzo, Nancy Mathews
College of Engineering and Mathematical Sciences Faculty Publications
There is growing environmental psychology and behavior literature with mixed empirical evidence about the influence of public risk perceptions on the adoption of environmentally friendly “green behaviors”. Adoption of stormwater green infrastructure on residential properties, while costlier in the short term compared to conventional greywater infrastructure, plays an important role in the reduction of nutrient loading from non-point sources into freshwater rivers and lakes. In this study, we use Bayesian Belief Networks (BBNs) to analyze a 2015 survey dataset (sample size = 472 respondents) about the adoption of green infrastructure (GSI) in Vermont’s residential areas, most of which are located …
Novel Evolutionary Algorithm Identifies Interactions Driving Infestation Of Triatoma Dimidiata, A Chagas Disease Vector, John P. Hanley, Donna M. Rizzo, Lori Stevens, Sara Helms Cahan, Patricia L. Dorn, Leslie A. Morrissey, Antonieta Guadalupe Rodas, Lucia C. Orantes, Carlota Monroy
Novel Evolutionary Algorithm Identifies Interactions Driving Infestation Of Triatoma Dimidiata, A Chagas Disease Vector, John P. Hanley, Donna M. Rizzo, Lori Stevens, Sara Helms Cahan, Patricia L. Dorn, Leslie A. Morrissey, Antonieta Guadalupe Rodas, Lucia C. Orantes, Carlota Monroy
College of Engineering and Mathematical Sciences Faculty Publications
Chagas disease is a lethal, neglected tropical disease. Unfortunately, aggressive insecticide-spraying campaigns have not been able to eliminate domestic infestation of Triatoma dimidiata, the native vector in Guatemala. To target interventions toward houses most at risk of infestation, comprehensive socioeconomic and entomologic surveys were conducted in two towns in Jutiapa, Guatemala. Given the exhaustively large search space associated with combinations of risk factors, traditional statistics are limited in their ability to discover risk factor interactions. Two recently developed statistical evolutionary algorithms, specifically designed to accommodate risk factor interactions and heterogeneity, were applied to this large combinatorial search space and used …
Hahahahaha, Duuuuude, Yeeessss!: A Two-Parameter Characterization Of Stretchable Words And The Dynamics Of Mistypings And Misspellings, Tyler J. Gray, Christopher M. Danforth, Peter Sheridan Dodds
Hahahahaha, Duuuuude, Yeeessss!: A Two-Parameter Characterization Of Stretchable Words And The Dynamics Of Mistypings And Misspellings, Tyler J. Gray, Christopher M. Danforth, Peter Sheridan Dodds
College of Engineering and Mathematical Sciences Faculty Publications
Stretched words like 'heellllp' or 'heyyyyy' are a regular feature of spoken language, often used to emphasize or exaggerate the underlying meaning of the root word. While stretched words are rarely found in formal written language and dictionaries, they are prevalent within social media. In this paper, we examine the frequency distributions of 'stretchable words' found in roughly 100 billion tweets authored over an 8 year period. We introduce two central parameters, 'balance' and 'stretch', that capture their main characteristics, and explore their dynamics by creating visual tools we call 'balance plots' and 'spelling trees'. We discuss how the tools …
Temperature Controls Production But Hydrology Regulates Export Of Dissolved Organic Carbon At The Catchment Scale, Hang Wen, Julia Perdrial, Benjamin W. Abbott, Susana Bernal, Remi Dupas, Sarah E. Godsey, Adrian Harpold, Donna Rizzo, Kristen Underwood, Thomas Adler, Gary Sterle, Li Li
Temperature Controls Production But Hydrology Regulates Export Of Dissolved Organic Carbon At The Catchment Scale, Hang Wen, Julia Perdrial, Benjamin W. Abbott, Susana Bernal, Remi Dupas, Sarah E. Godsey, Adrian Harpold, Donna Rizzo, Kristen Underwood, Thomas Adler, Gary Sterle, Li Li
College of Engineering and Mathematical Sciences Faculty Publications
Lateral carbon flux through river networks is an important and poorly understood component of the global carbon budget. This work investigates how temperature and hydrology control the production and export of dissolved organic carbon (DOC) in the Susquehanna Shale Hills Critical Zone Observatory in Pennsylvania, USA. Using field measurements of daily stream discharge, evapotranspiration, and stream DOC concentration, we calibrated the catchment-scale biogeochemical reactive transport model BioRT-Flux-PIHM (Biogeochemical Reactive Transport-Flux-Penn State Integrated Hydrologic Model, BFP), which met the satisfactory standard of a Nash-Sutcliffe efficiency (NSE) value greater than 0.5. We used the calibrated model to estimate and compare the daily …
Noncooperative Dynamics In Election Interference, David Rushing Dewhurst, Christopher M. Danforth, Peter Sheridan Dodds
Noncooperative Dynamics In Election Interference, David Rushing Dewhurst, Christopher M. Danforth, Peter Sheridan Dodds
College of Engineering and Mathematical Sciences Faculty Publications
Foreign power interference in domestic elections is an existential threat to societies. Manifested through myriad methods from war to words, such interference is a timely example of strategic interaction between economic and political agents. We model this interaction between rational game players as a continuous-time differential game, constructing an analytical model of this competition with a variety of payoff structures. All-or-nothing attitudes by only one player regarding the outcome of the game lead to an arms race in which both countries spend increasing amounts on interference and counterinterference operations. We then confront our model with data pertaining to the Russian …
A Tandem Evolutionary Algorithm For Identifying Causal Rules From Complex Data, John P. Hanley, Donna M. Rizzo, Jeffrey S. Buzas, Margaret J. Eppstein
A Tandem Evolutionary Algorithm For Identifying Causal Rules From Complex Data, John P. Hanley, Donna M. Rizzo, Jeffrey S. Buzas, Margaret J. Eppstein
College of Engineering and Mathematical Sciences Faculty Publications
We propose a new evolutionary approach for discovering causal rules in complex classification problems from batch data. Key aspects include (a) the use of a hypergeometric probability mass function as a principled statistic for assessing fitness that quantifies the probability that the observed association between a given clause and target class is due to chance, taking into account the size of the dataset, the amount of missing data, and the distribution of outcome categories, (b) tandem age-layered evolutionary algorithms for evolving parsimonious archives of conjunctive clauses, and disjunctions of these conjunctions, each of which have probabilistically significant associations with outcome …
Fragmentation And Inefficiencies In Us Equity Markets: Evidence From The Dow 30, Brian F. Tivnan, David Rushing Dewhurst, Colin M. Van Oort, John H. Ring, Tyler J. Gray, Brendan F. Tivnan, Matthew T.K. Koehler, Matthew T. Mcmahon, David M. Slater, Jason G. Veneman, Christopher M. Danforth
Fragmentation And Inefficiencies In Us Equity Markets: Evidence From The Dow 30, Brian F. Tivnan, David Rushing Dewhurst, Colin M. Van Oort, John H. Ring, Tyler J. Gray, Brendan F. Tivnan, Matthew T.K. Koehler, Matthew T. Mcmahon, David M. Slater, Jason G. Veneman, Christopher M. Danforth
College of Engineering and Mathematical Sciences Faculty Publications
Using the most comprehensive source of commercially available data on the US National Market System, we analyze all quotes and trades associated with Dow 30 stocks in calendar year 2016 from the vantage point of a single and fixed frame of reference. We find that inefficiencies created in part by the fragmentation of the equity marketplace are relatively common and persist for longer than what physical constraints may suggest. Information feeds reported different prices for the same equity more than 120 million times, with almost 64 million dislocation segments featuring meaningfully longer duration and higher magnitude. During this period, roughly …
Electricity Rates For The Zero Marginal Cost Grid, Helen Lo, Seth Blumsack, Paul Hines, Sean Meyn
Electricity Rates For The Zero Marginal Cost Grid, Helen Lo, Seth Blumsack, Paul Hines, Sean Meyn
College of Engineering and Mathematical Sciences Faculty Publications
The electricity industry is rapidly changing: costs are increasingly dominated by capital and technology is turning loads into resources. This is similar to the early days of the Internet. Building on rate-structures used in the communications industry, utilities of the future should offer customers a portfolio of service contract options that provide a signal to the utility regarding the type and amount of infrastructure that should be deployed.
A Crowdsourcing Approach To Understand Weight And Weight Loss In Men, Tiffany Rounds, Josh Bongard, Paul Hines, Jean Harvey
A Crowdsourcing Approach To Understand Weight And Weight Loss In Men, Tiffany Rounds, Josh Bongard, Paul Hines, Jean Harvey
College of Engineering and Mathematical Sciences Faculty Publications
No abstract provided.
Social Media Usage Patterns During Natural Hazards, Meredith T. Niles, Benjamin F. Emery, Andrew J. Reagan, Peter Sheridan Dodds, Christopher M. Danforth
Social Media Usage Patterns During Natural Hazards, Meredith T. Niles, Benjamin F. Emery, Andrew J. Reagan, Peter Sheridan Dodds, Christopher M. Danforth
College of Engineering and Mathematical Sciences Faculty Publications
Natural hazards are becoming increasingly expensive as climate change and development are exposing communities to greater risks. Preparation and recovery are critical for climate change resilience, and social media are being used more and more to communicate before, during, and after disasters. While there is a growing body of research aimed at understanding how people use social media surrounding disaster events, most existing work has focused on a single disaster case study. In the present study, we analyze five of the costliest disasters in the last decade in the United States (Hurricanes Irene and Sandy, two sets of tornado outbreaks, …
Application Of Unmanned Aircraft System (Uas) For Monitoring Bank Erosion Along River Corridors, Scott D. Hamshaw, Tayler Engel, Donna M. Rizzo, Jarlath O’Neil-Dunne, Mandar M. Dewoolkar
Application Of Unmanned Aircraft System (Uas) For Monitoring Bank Erosion Along River Corridors, Scott D. Hamshaw, Tayler Engel, Donna M. Rizzo, Jarlath O’Neil-Dunne, Mandar M. Dewoolkar
College of Engineering and Mathematical Sciences Faculty Publications
Excessive streambank erosion is a significant source of fine sediments and associated nutrients in many river systems as well as poses risk to infrastructure. Geomorphic change detection using high-resolution topographic data is a useful method for monitoring the extent of bank erosion along river corridors. Recent advances in an unmanned aircraft system (UAS) and structure from motion (SfM) photogrammetry techniques allow acquisition of high-resolution topographic data, which are the methods used in this study. To evaluate the effectiveness of UAS-based photogrammetry for monitoring bank erosion, a fixed-wing UAS was deployed to survey 20 km of river corridors in central Vermont, …
From The Household To Watershed: A Cross-Scale Analysis Of Residential Intention To Adopt Green Stormwater Infrastructure, Sarah Coleman, Stephanie Hurley, Donna Rizzo, Christopher Koliba, Asim Zia
From The Household To Watershed: A Cross-Scale Analysis Of Residential Intention To Adopt Green Stormwater Infrastructure, Sarah Coleman, Stephanie Hurley, Donna Rizzo, Christopher Koliba, Asim Zia
College of Engineering and Mathematical Sciences Faculty Publications
Improved stormwater management for the protection of water resources requires bottom-up stewardship from landowners, including adoption of Green Stormwater Infrastructure (GSI). We use a statewide survey of Vermont paired with a cross-scale and spatial analysis to evaluate the influence of interacting spatial, social, and physical factors on residential intention to adopt GSI across a complex social-ecological landscape. Specifically, we focus on how three GSI practices, (“rain garden (bio retention),” “infiltration trenches,” and “actively divert roof runoff to a rain barrel/lawn/garden instead of the street/sewer”) vary with barriers to adoption, and household attributes across stormwater contexts from the household to watershed …
English Verb Regularization In Books And Tweets, Tyler J. Gray, Andrew J. Reagan, Peter Sheridan Dodds, Christopher M. Danforth
English Verb Regularization In Books And Tweets, Tyler J. Gray, Andrew J. Reagan, Peter Sheridan Dodds, Christopher M. Danforth
College of Engineering and Mathematical Sciences Faculty Publications
The English language has evolved dramatically throughout its lifespan, to the extent that a modern speaker of Old English would be incomprehensible without translation. One concrete indicator of this process is the movement from irregular to regular (-ed) forms for the past tense of verbs. In this study we quantify the extent of verb regularization using two vastly disparate datasets: (1) Six years of published books scanned by Google (2003-2008), and (2) A decade of social media messages posted to Twitter (2008-2017). We find that the extent of verb regularization is greater on Twitter, taken as a whole, than in …
Uncovering Vector, Parasite, Blood Meal And Microbiome Patterns From Mixed-Dna Specimens Of The Chagas Disease Vector Triatoma Dimidiata, Lucia C. Orantes, Carlota Monroy, Patricia L. Dorn, Lori Stevens, Donna M. Rizzo, Leslie Morrissey, John P. Hanley, Antonieta Guadalupe Rodas, Bethany Richards, Kimberly F. Wallin, Sara Helms Cahan
Uncovering Vector, Parasite, Blood Meal And Microbiome Patterns From Mixed-Dna Specimens Of The Chagas Disease Vector Triatoma Dimidiata, Lucia C. Orantes, Carlota Monroy, Patricia L. Dorn, Lori Stevens, Donna M. Rizzo, Leslie Morrissey, John P. Hanley, Antonieta Guadalupe Rodas, Bethany Richards, Kimberly F. Wallin, Sara Helms Cahan
College of Engineering and Mathematical Sciences Faculty Publications
Chagas disease, considered a neglected disease by the World Health Organization, is caused by the protozoan parasite Trypanosoma cruzi, and transmitted by >140 triatomine species across the Americas. In Central America, the main vector is Triatoma dimidiata, an opportunistic blood meal feeder inhabiting both domestic and sylvatic ecotopes. Given the diversity of interacting biological agents involved in the epidemiology of Chagas disease, having simultaneous information on the dynamics of the parasite, vector, the gut microbiome of the vector, and the blood meal source would facilitate identifying key biotic factors associated with the risk of T. cruzi transmission. In this study, …
Continuum Rich-Get-Richer Processes: Mean Field Analysis With An Application To Firm Size, David Rushing Dewhurst, Christopher M. Danforth, Peter Sheridan Dodds
Continuum Rich-Get-Richer Processes: Mean Field Analysis With An Application To Firm Size, David Rushing Dewhurst, Christopher M. Danforth, Peter Sheridan Dodds
College of Engineering and Mathematical Sciences Faculty Publications
Classical rich-get-richer models have found much success in being able to broadly reproduce the statistics and dynamics of diverse real complex systems. These rich-get-richer models are based on classical urn models and unfold step by step in discrete time. Here, we consider a natural variation acting on a temporal continuum in the form of a partial differential equation (PDE). We first show that the continuum version of Simon's canonical preferential attachment model exhibits an identical size distribution. In relaxing Simon's assumption of a linear growth mechanism, we consider the case of an arbitrary growth kernel and find the general solution …
Divergent Discourse Between Protests And Counter-Protests: #Blacklivesmatter And #Alllivesmatter, Ryan J. Gallagher, Andrew J. Reagan, Christopher M. Danforth, Peter Sheridan Dodds
Divergent Discourse Between Protests And Counter-Protests: #Blacklivesmatter And #Alllivesmatter, Ryan J. Gallagher, Andrew J. Reagan, Christopher M. Danforth, Peter Sheridan Dodds
College of Engineering and Mathematical Sciences Faculty Publications
Since the shooting of Black teenager Michael Brown by White police officer Darren Wilson in Ferguson, Missouri, the protest hashtag #BlackLivesMatter has amplified critiques of extrajudicial killings of Black Americans. In response to #BlackLivesMatter, other Twitter users have adopted #AllLivesMatter, a counter-protest hashtag whose content argues that equal attention should be given to all lives regardless of race. Through a multi-level analysis of over 860,000 tweets, we study how these protests and counter-protests diverge by quantifying aspects of their discourse. We find that #AllLivesMatter facilitates opposition between #BlackLivesMatter and hashtags such as #PoliceLivesMatter and #BlueLivesMatter in such a way that …
Erratum: Reducing Cascading Failure Risk By Increasing Infrastructure Network Interdependence, Mert Korkali, Jason G. Veneman, Brian F. Tivnan, James P. Bagrow, Paul D.H. Hines
Erratum: Reducing Cascading Failure Risk By Increasing Infrastructure Network Interdependence, Mert Korkali, Jason G. Veneman, Brian F. Tivnan, James P. Bagrow, Paul D.H. Hines
College of Engineering and Mathematical Sciences Faculty Publications
This corrects the article DOI: 10.1038/srep44499.
Energy And Complexity, Zofia Lukszo, Ettore Bompard, Paul Hines, Liz Varga
Energy And Complexity, Zofia Lukszo, Ettore Bompard, Paul Hines, Liz Varga
College of Engineering and Mathematical Sciences Faculty Publications
No abstract provided.
Forecasting The Onset And Course Of Mental Illness With Twitter Data, Andrew G. Reece, Andrew J. Reagan, Katharina L.M. Lix, Peter Sheridan Dodds, Christopher M. Danforth, Ellen J. Langer
Forecasting The Onset And Course Of Mental Illness With Twitter Data, Andrew G. Reece, Andrew J. Reagan, Katharina L.M. Lix, Peter Sheridan Dodds, Christopher M. Danforth, Ellen J. Langer
College of Engineering and Mathematical Sciences Faculty Publications
We developed computational models to predict the emergence of depression and Post-Traumatic Stress Disorder in Twitter users. Twitter data and details of depression history were collected from 204 individuals (105 depressed, 99 healthy). We extracted predictive features measuring affect, linguistic style, and context from participant tweets (N = 279,951) and built models using these features with supervised learning algorithms. Resulting models successfully discriminated between depressed and healthy content, and compared favorably to general practitioners' average success rates in diagnosing depression, albeit in a separate population. Results held even when the analysis was restricted to content posted before first depression diagnosis. …
Erratum To: Instagram Photos Reveal Predictive Markers Of Depression (Epj Data Science, (2017), 6, 1, (15), 10.1140/Epjds/S13688-017-0110-Z), Andrew G. Reece, Christopher M. Danforth
Erratum To: Instagram Photos Reveal Predictive Markers Of Depression (Epj Data Science, (2017), 6, 1, (15), 10.1140/Epjds/S13688-017-0110-Z), Andrew G. Reece, Christopher M. Danforth
College of Engineering and Mathematical Sciences Faculty Publications
Upon publication of the original article [1], it was noticed that Figure 2 contained an error. The horizontal bars for the likes row were incorrectly shown as blue. The horizontal bars for the ‘likes’ row should be orange. This has now been acknowledged and corrected in this erratum. The correct Figure 2 is shown below. In the section Method, subsection Improving data quality, the sentence ‘We also excluded participants with CES-D scores of 22 or higher. should read as We also excluded participants with CES-D scores of 21 or lower. This has now been acknowledged and corrected in this erratum. …
Instagram Photos Reveal Predictive Markers Of Depression, Andrew G. Reece, Christopher M. Danforth
Instagram Photos Reveal Predictive Markers Of Depression, Andrew G. Reece, Christopher M. Danforth
College of Engineering and Mathematical Sciences Faculty Publications
Using Instagram data from 166 individuals, we applied machine learning tools to successfully identify markers of depression. Statistical features were computationally extracted from 43,950 participant Instagram photos, using color analysis, metadata components, and algorithmic face detection. Resulting models outperformed general practitioners’ average unassisted diagnostic success rate for depression. These results held even when the analysis was restricted to posts made before depressed individuals were first diagnosed. Human ratings of photo attributes (happy, sad, etc.) were weaker predictors of depression, and were uncorrelated with computationally-generated features. These results suggest new avenues for early screening and detection of mental illness.
Sentiment Analysis Methods For Understanding Large-Scale Texts: A Case For Using Continuum-Scored Words And Word Shift Graphs, Andrew J. Reagan, Christopher M. Danforth, Brian Tivnan, Jake Ryland Williams, Peter Sheridan Dodds
Sentiment Analysis Methods For Understanding Large-Scale Texts: A Case For Using Continuum-Scored Words And Word Shift Graphs, Andrew J. Reagan, Christopher M. Danforth, Brian Tivnan, Jake Ryland Williams, Peter Sheridan Dodds
College of Engineering and Mathematical Sciences Faculty Publications
The emergence and global adoption of social media has rendered possible the real-time estimation of population-scale sentiment, an extraordinary capacity which has profound implications for our understanding of human behavior. Given the growing assortment of sentiment-measuring instruments, it is imperative to understand which aspects of sentiment dictionaries contribute to both their classification accuracy and their ability to provide richer understanding of texts. Here, we perform detailed, quantitative tests and qualitative assessments of 6 dictionary-based methods applied to 4 different corpora, and briefly examine a further 20 methods. We show that while inappropriate for sentences, dictionary-based methods are generally robust in …
Evaluating Spatial Variability In Sediment And Phosphorus Concentration-Discharge Relationships Using Bayesian Inference And Self-Organizing Maps, Kristen L. Underwood, Donna M. Rizzo, Andrew W. Schroth, Mandar M. Dewoolkar
Evaluating Spatial Variability In Sediment And Phosphorus Concentration-Discharge Relationships Using Bayesian Inference And Self-Organizing Maps, Kristen L. Underwood, Donna M. Rizzo, Andrew W. Schroth, Mandar M. Dewoolkar
College of Engineering and Mathematical Sciences Faculty Publications
Given the variable biogeochemical, physical, and hydrological processes driving fluvial sediment and nutrient export, the water science and management communities need data-driven methods to identify regions prone to production and transport under variable hydrometeorological conditions. We use Bayesian analysis to segment concentration-discharge linear regression models for total suspended solids (TSS) and particulate and dissolved phosphorus (PP, DP) using 22 years of monitoring data from 18 Lake Champlain watersheds. Bayesian inference was leveraged to estimate segmented regression model parameters and identify threshold position. The identified threshold positions demonstrated a considerable range below and above the median discharge—which has been used previously …
Evaluation Of A Proposal For Reliable Low-Cost Grid Power With 100% Wind, Water, And Solar, Christopher T.M. Clack, Staffan A. Qvist, Jay Apt, Morgan Bazilian, Adam R. Brandt, Ken Caldeira, Steven J. Davis, Victor Diakov, Mark A. Handschy, Paul D.H. Hines, Paulina Jaramillo, Daniel M. Kammen, Jane C.S. Long, M. Granger Morgan, Adam Reed, Varun Sivaram, James Sweeney, George R. Tynan, David G. Victor, John P. Weyant, Jay F. Whitacre
Evaluation Of A Proposal For Reliable Low-Cost Grid Power With 100% Wind, Water, And Solar, Christopher T.M. Clack, Staffan A. Qvist, Jay Apt, Morgan Bazilian, Adam R. Brandt, Ken Caldeira, Steven J. Davis, Victor Diakov, Mark A. Handschy, Paul D.H. Hines, Paulina Jaramillo, Daniel M. Kammen, Jane C.S. Long, M. Granger Morgan, Adam Reed, Varun Sivaram, James Sweeney, George R. Tynan, David G. Victor, John P. Weyant, Jay F. Whitacre
College of Engineering and Mathematical Sciences Faculty Publications
A number of analyses, meta-Analyses, and assessments, including those performed by the Intergovernmental Panel on Climate Change, the National Oceanic and Atmospheric Administration, the National Renewable Energy Laboratory, and the International Energy Agency, have concluded that deployment of a diverse portfolio of clean energy technologies makes a transition to a low-carbon-emission energy system both more feasible and less costly than other pathways. In contrast, Jacobson et al. [Jacobson MZ, Delucchi MA, Cameron MA, Frew BA (2015) Proc Natl Acad Sci USA 112(49):15060-15065] argue that it is feasible to provide "low-cost solutions to the grid reliability problem with 100% penetration of …
Characterizing Landscape-Scale Erosion Using 10be In Detrital Fluvial Sediment: Slope-Based Sampling Strategy Detects The Effect Of Widespread Dams, Lucas J. Reusser, Paul R. Bierman, Donna M. Rizzo, Eric W. Portenga, Dylan H. Rood
Characterizing Landscape-Scale Erosion Using 10be In Detrital Fluvial Sediment: Slope-Based Sampling Strategy Detects The Effect Of Widespread Dams, Lucas J. Reusser, Paul R. Bierman, Donna M. Rizzo, Eric W. Portenga, Dylan H. Rood
College of Engineering and Mathematical Sciences Faculty Publications
Concentrations of in situ 10Be measured in detrital fluvial sediment are frequently used to estimate long-term erosion rates of drainage basins. In many regions, basin-averaged erosion rates are positively correlated with basin average slope. The slope dependence of erosion allows model-based erosion rate estimation for unsampled basins and basins where human disturbance may have biased cosmogenic nuclide concentrations in sediment. Using samples collected from southeastern North America, we demonstrate an approach that explicitly considers the relationship between average basin slope and erosion rate. Because dams and reservoirs are ubiquitous on larger channels in the field area, we selected 36 undammed …
Simon's Fundamental Rich-Get-Richer Model Entails A Dominant First-Mover Advantage, Peter Sheridan Dodds, David Rushing Dewhurst, Fletcher F. Hazlehurst, Colin M. Van Oort, Lewis Mitchell, Andrew J. Reagan, Jake Ryland Williams, Christopher M. Danforth
Simon's Fundamental Rich-Get-Richer Model Entails A Dominant First-Mover Advantage, Peter Sheridan Dodds, David Rushing Dewhurst, Fletcher F. Hazlehurst, Colin M. Van Oort, Lewis Mitchell, Andrew J. Reagan, Jake Ryland Williams, Christopher M. Danforth
College of Engineering and Mathematical Sciences Faculty Publications
Herbert Simon's classic rich-get-richer model is one of the simplest empirically supported mechanisms capable of generating heavy-tail size distributions for complex systems. Simon argued analytically that a population of flavored elements growing by either adding a novel element or randomly replicating an existing one would afford a distribution of group sizes with a power-law tail. Here, we show that, in fact, Simon's model does not produce a simple power-law size distribution as the initial element has a dominant first-mover advantage, and will be overrepresented by a factor proportional to the inverse of the innovation probability. The first group's size discrepancy …
Reducing Cascading Failure Risk By Increasing Infrastructure Network Interdependence, Mert Korkali, Jason G. Veneman, Brian F. Tivnan, James P. Bagrow, Paul D.H. Hines
Reducing Cascading Failure Risk By Increasing Infrastructure Network Interdependence, Mert Korkali, Jason G. Veneman, Brian F. Tivnan, James P. Bagrow, Paul D.H. Hines
College of Engineering and Mathematical Sciences Faculty Publications
Increased interconnection between critical infrastructure networks, such as electric power and communications systems, has important implications for infrastructure reliability and security. Others have shown that increased coupling between networks that are vulnerable to internetwork cascading failures can increase vulnerability. However, the mechanisms of cascading in these models differ from those in real systems and such models disregard new functions enabled by coupling, such as intelligent control during a cascade. This paper compares the robustness of simple topological network models to models that more accurately reflect the dynamics of cascading in a particular case of coupled infrastructures. First, we compare a …
Connecting Every Bit Of Knowledge: The Structure Of Wikipedia's First Link Network, Mark Ibrahim, Christopher M. Danforth, Peter Sheridan Dodds
Connecting Every Bit Of Knowledge: The Structure Of Wikipedia's First Link Network, Mark Ibrahim, Christopher M. Danforth, Peter Sheridan Dodds
College of Engineering and Mathematical Sciences Faculty Publications
Apples, porcupines, and the most obscure Bob Dylan song—is every topic a few clicks from Philosophy? Within Wikipedia, the surprising answer is yes: nearly all paths lead to Philosophy. Wikipedia is the largest, most meticulously indexed collection of human knowledge ever amassed. More than information about a topic, Wikipedia is a web of naturally emerging relationships. By following the first link in each article, we algorithmically construct a directed network of all 4.7 million articles: Wikipedia's First Link Network. Here, we study the English edition of Wikipedia's First Link Network for insight into how the many articles on inventions, places, …