Mathematics & Statistics Colloquium Tuesdays in DMTI 111

For virtual event links or to be added to the colloquium mailing list please contact mathstat@american.edu.

See also previous colloquium Abstracts and YouTube Playlist.

If interested in presenting to the Colloquium, please contact the organizers: Stephen D. Casey (scasey@american.edu), Nimai Mehta (mehta@american.edu).

Fall 2022

  • December 7, 2022, 2:30 PM:
    Zois Boukouvalas, AU,
    Efficient and Explainable Multivariate Data Fusion for Misinformation Detection During High Impact Events
    Abstract: With the evolution of social media, cyberspace has become the de-facto medium for users to communicate during high-impact events such as natural disasters, terrorist attacks, and periods of political unrest. However, during such high-impact events, misinformation on social media can rapidly spread, affecting decision-making and creating social unrest. Identifying the spread of misinformation during high-impact events is a significant data challenge, given the variety of data associated with social media posts. Recent machine learning advances have shown promise for detecting misinformation, however, there are still key limitations that makes this a significant challenge. These limitations include the effective and efficient modeling of the underlying non-linear associations of multi-modal data as well as the explainability of a system geared at the detection of misinformation. In this talk we present a novel multivariate data fusion framework based on pre-trained deep learning features and a well-structured and parameter-free joint blind source separation method named independent vector analysis, that can reliably respond to this set of limitations. We present the mathematical formulation of the new data fusion algorithm, demonstrate its effectiveness, and present multiple explainability case studies using a popular multi-modal dataset that consists of tweets during several high-impact events.
  • November 29, 2:30 PM: 
    John T. Rigsby,
    Chief Analytics Officer, Defense Technical Information Center
    "Data Science Projects at the Defense"
    Abstract: The mission of the Defense Technical Information Center (DTIC) is to aggregate and fuse science and technology data to rapidly, accurately and reliably deliver the knowledge needed to develop the next generation of technologies to support our Warfighters and help assure national security. This presentation will cover current efforts of the DTIC Data Science and Analytics Cell to support this mission.
  • November 1, Elicia John, AU,
    "Smartphone Data Reveal Neighborhood-Level
    Racial Disparities in Police Presence
    "
    Abstract : While research on policing has focused on documented actions such as stops and arrests, less is known about patrols and presence. We map the neighborhood movement of nearly ten thousand officers across 21 of America’s largest cities using anonymized smartphone data. We find that police spend more time in neighborhoods with predominantly Hispanic, Asian, and – in particular – Black residents. This disparity persists after controlling for density, socioeconomic, and crime-driven demand for policing, and is lower in cities with a higher share of Black police supervisors (but not officers). It is also associated with a higher number of arrests in some of these communities.

  • October 25, "FDA Cybersecurity, Counterintelligence, and Insider:
    Threat Program Overview
    "
    Craig Taylor, US Food and Drug Administration (FDA) Chief Information Security Officer (CISO)
    Leah Buckley, FDA (Director, Counterintelligence and Insider Threat)
  • October 18, Daniel Bernhofen,
    Testing the Invisible Hand with a Natural Experiment  
    Abstract : A central premise of economics is that the market system allocates resources in the right direction, as if directed by an invisible hand. But what is the right direction? The economic subfield of general equilibrium theory has provided an answer to this question via the First Funamental Welfare Theorem, which employs Pareto optimality as a criteria for the right direction and states that a competitive general equilibrium is Pareto optimal. For this reason, the First Fundamental Welfare Theorem has also been labeled the invisible hand theorem and is viewed as a proof of Adam Smith’s famous conjecture that in a market economy individuals are “…led by an invisible hand to promote an end which was no part of (their) intention” (Adam Smith, Wealth of Nations, 1776, vol I, Book IV, Ch II, p.477). A major criticism of the invisible hand theorem is that it holds under very strong conditions and can’t be refuted by the data.

    This lecture provides an overview of a research agenda that employs a natural experiment to test some fundamental theorems in international trade, which is a subfield of general equilibrium theory. First, I show that the mathematical structure of these theorems can be summarized as P∙Z>0, which I call the invisible hand inequality. Second, I discuss the relationship between the invisible hand theorem and the invisible hand inequality. Third, I discuss how the 19th century opening up of Japan to international trade after 200 years of self-imposed isolation provides a natural experiment to test the invisible hand inequalities and provide evidence that decentralized markets allocate resources in the (right) direction of comparative advantage.

    For a brief background reading for this talk see: Gains from Trade: Evidence from 19th Century Japan.
  • September 27, Emmanouil “Manolis” Maragkakis
    Abstract: Aging, while seemingly a universal feature of life, is surprisingly difficult to define. New studies describe aging as a correlated set of declines in functioning with advancing chronological age, which generally begins after sexual maturity. Understanding the regulation of these declines is crucial for the development of interventions and disease therapies but requires the coordinated integration of multidimensional information. Dr. Maragkakis focuses on understanding this high-dimensional regulation of gene expression as a key component of discovering the mechanistic basis of the physiology and diseases of aging. His lab employs experimental and computational approaches to discover fundamental biological mechanisms that control RNA stability and dynamics. They develop tools to integrate high-throughput short- and long-read sequencing and machine learning to decipher the defining features of co-translational mRNA decay, how it is regulated, and the downstream effects of RNA dynamics in aging organs, tissues, and cells.
  • September 20, Zeying Wang, AU
    Abstract: The Talk is situated in the area of Combinatorial Design Theory, a subfield of Discrete Mathematics. In particular, I will focus on so-called partial difference sets (PDSs) in finite abelian groups. These are combinatorially defined subsets of a finite group that give rise to highly symmetric graphs called strongly regular Caley graphs. A few years ago we proved a theorem for strongly regular graphs that provides numerical restrictions on the number of fixed vertices and the number of vertices mapped to adjacent vertices under an automorphism. We then used this result to develop some new techniques to study regular partial difference sets in abelian groups. We have proved several non-existence results and classification results for partial difference sets in abelian groups. Also we completely answered a classical question from the 1990s: "For which odd positive integer v>1, can we find a Paley type partial difference set in an abelian group of order v?" In this talk I plan to give an overview of these results. The talk will be accessible to non-specialists.

More Mathstat Events

  • District Fourier Talks are the annual meeting of local mathematicians, engineers, and applied scientists exchanging and exploring recent advances and trends in harmonic analysis and applications.

AUcollege

Colloquium Videos

Catch up on some of our weekly colloquia.

Videos in this playlist

To play a specific video, use the playlist icon in the player or view each video on YouTube.

  1. AUcollege

    Experiencing Medieval Astronomy with an Astrolabe

  2. AUcollege

    Analytic Bezout Equations and Sampling in Rectangular and Radial Coordinates

  3. AUcollege

    Supporting the fight against the proliferation of chemicals weapons through cheminformatics

  4. AUcollege

    Multi-scale mechanistic modelling of the host defense in invasive aspergillosis

  5. AUcollege

    Double Reduction Estimation and Equilibrium Tests in Natural Autopolyploid Populations

  6. AUcollege

    Student Summer Research Experience Projects

  7. AUcollege

    Differential Privacy and the 2020 Census in the United States

  8. AUcollege

    Independent Component and Vector Analyses for Explainable Detection of Misinformation During High...

  9. AUcollege

    The Analysis of Periodic Point Processes

  10. AUcollege

    Weight calibration to improve efficiency for estimating pure absolute risks...

  11. AUcollege

    A Bilevel Optimization Method for an Exact Solution to Equilibrium Problems with Binary Variables

  12. AUcollege

    An Analysis of IQ-Link (TM)

  13. AUcollege

    Modeling Heat and Mass Transport in Cryobiology

  14. AUcollege

    Artistic mathematics: truth and beauty

  15. AUcollege

    Harnessing Dataset Complexity in Classification Tasks

  16. AUcollege

    Machine Learning Improves Estimates of Environmental Exposures

  17. AUcollege

    "Hitting Objects with Random Walks": John Nolan on Brownian Motion

  18. AUcollege

    Incorporating survival data to case-control studies with incident and prevalent cases

  19. AUcollege

    Statistical analysis of epidemic counts data

  20. AUcollege

    A New Architecture for Cell Phones, Sampling via Projection for UWB and AFB Systems

  21. AUcollege

    John Eltinge Talk

Past Colloquia

  • September 27, Emmanouil “Manolis” Maragkakis
    Abstract: Aging, while seemingly a universal feature of life, is surprisingly difficult to define. New studies describe aging as a correlated set of declines in functioning with advancing chronological age, which generally begins after sexual maturity. Understanding the regulation of these declines is crucial for the development of interventions and disease therapies but requires the coordinated integration of multidimensional information. Dr. Maragkakis focuses on understanding this high-dimensional regulation of gene expression as a key component of discovering the mechanistic basis of the physiology and diseases of aging. His lab employs experimental and computational approaches to discover fundamental biological mechanisms that control RNA stability and dynamics. They develop tools to integrate high-throughput short- and long-read sequencing and machine learning to decipher the defining features of co-translational mRNA decay, how it is regulated, and the downstream effects of RNA dynamics in aging organs, tissues, and cells.
  • September 20, Zeying Wang
    Abstract : The Talk is situated in the area of Combinatorial Design Theory, a subfield of Discrete Mathematics. In particular, I will focus on so-called partial difference sets (PDSs) in finite abelian groups. These are combinatorially defined subsets of a finite group that give rise to highly symmetric graphs called strongly regular Caley graphs. A few years ago we proved a theorem for strongly regular graphs that provides numerical restrictions on the number of fixed vertices and the number of vertices mapped to adjacent vertices under an automorphism. We then used this result to develop some new techniques to study regular partial difference sets in abelian groups. We have proved several non-existence results and classification results for partial difference sets in abelian groups. Also we completely answered a classical question from the 1990s: "For which odd positive integer v>1, can we find a Paley type partial difference set in an abelian group of order v?" In this talk I plan to give an overview of these results. The talk will be accessible to non-specialists.

 

  • Feb. 9, 2021: Sauleh Siddiqui (AU)
    "A Bilevel Optimization Method for an Exact Solution to Equilibrium Problems with Binary Variables" 
  • Feb. 16, 2021: Yei Eun Shin (NIH, NCI)
    "Weight calibration to improve efficiency for estimating pure absolute risks from the proportional and additive hazards model in the nested case-control design"
  • Feb. 23, 2021: Nate Strawn (Georgetown, NIH, NCI)
    "Isometric Data Embeddings: Visualizations and Lifted Signal Processing"
  • Mar. 16, 2021: Stephen D. Casey (AU, Personnel Data Research Institute)
    Thomas J. Casey (AU)
    "The Analysis of Periodic Point Processes"
  • Mar. 23, 2021: Zois Boukouvalas (AU)
    "Independent Component and Vector Analyses for Explainable Detection of Misinformation During High Impact Events"
  • Mar. 30, 2021: Der-Chen Chang (Georgetown)
    "Introduction to ̄∂-Neumann Problem"
  • Apr. 14, 2021: John M. Abowd (US Census Bureau)
    Title TBD

9/8/2020: Stephen D. Casey, American University; Norbert Wiener Center University of Maryland
A New Architecture for Cell Phones Sampling via Projection for UWB and AFB Systems

9/15/2020: Martha Dusenberry Pohl, American University 
Further Visualizations of the Census: ACS, Redistricting, Names Files; & HMDA using Shapefiles, BISG, Venn Diagrams, Quantification, 3-D rotation, & Animation

9/22/2020: Michael Baron, American University
Statistical analysis of epidemic counts data: modeling, detection of outbreaks, and recovery of missing data

9/29/2020: Soutrik Mandal, Division of Cancer Epidemiology and Genetics (National Cancer Institute, National Institutes of Health)
Incorporating survival data to case-control studies with incident and prevalent cases

10/13/2020: John P. Nolan, American University
Hitting objects with random walks

10/20/2020: Yuri Levin-Schwartz, Icahn School of Medicine at Mount Sinai 
Machine learning improves estimates of environmental exposures

10/27/2020: Nathalie Japkowicz, American University
Harnessing Dataset Complexity in Classification Tasks

11/10/2020: Anthony Kearsley, NIST

11/17/2020: Donna Dietz, American University 
An Analysis of IQ-Link (TM)

1/21/2020: Justin Pierce, Federal Reserve Washington DC
Examining the Decline in US Manufacturing Employment

1/28/2020: Ruth Pfeiffer, Biostatistics Branch, National Cancer Institution, NIH
Sufficient dimension reduction for high dimensional longitudinally measured biomarkers

2/11/2020: Erica L. Smith, Bureau of Justice Statistics, US Dept. of Justice
Overview of Department of Justice Statistical Data Collections Related to Gun Violence

2/18/2020: Sudip Bhattacharjee, University of Connecticut
A Text Mining and Machine Learning Platform to Classify Businesses into NAICS codes

2/25/2020: Avi Bender, National Technical Information Service (NTIS)
Data Science Skills for Delivering Mission Outcome: An interactive discussion with the Director of the National Technical Information Service (NTIS), US Department of Commerce

9/10/2019: Dr. Scott Parker, American University
Some useful information about the Wilcoxon-Mann Whitney test and effect size measurement

9/17/2019: Dr. Michael Robinson, American University
Radio Fox Hunting using Sheaves

9/24/2019: Dr. Zois Boukouvalas, American University
Data Fusion in the Age of Data: Recent Theoretical Advances and Applications

10/8/2019: Dr. Elizabeth Stuart, Johns Hopkins
Assessing and enhancing the generalizability of randomized trials to target populations

10/15/2019: Latif Khalil, JBS International, Inc. 
Entity Resolution Techniques to Significantly Improve Healthcare Data Quality

10/22/2019: Dennis Lucarelli, American University 
Steering qubits, cats and cars via gradient ascent in function space

10/29/2019: Michael Thieme, Assistant Director for Decennial Census Programs, Systems and Contracts
Census 2020 - Clear Vision for the Country 

11/12/2019: John Eltinge, US Census Bureau 
Transparency and Reproducibility in the Design, Testing, Implementation and Maintenance of Procedures for the Integration of Multiple Data Sources

11/19/2019: Xander Faber, Institute for Defense Analyses, Center for Computing Sciences