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2017–18 Colloquium Series

This Colloquium Series is sponsored by the Math and Computer Science Department. Unless otherwise noted, all talks take place in Jepson Hall Room 109 at 4:30 p.m. for spring 2018.

Starting at 4 p.m. light refreshments will be served in the lounge outside of Jepson 212 — please join us.

Talks will be added as they are scheduled; please check back often.

Up Next 

April 23  Student Research Presentations

David Clayton, Format Transforming Encryption

Mentor: Dr. Doug Szajda

Past Events

March 26  Jyh-Ming Lien,  Associate Professor, Department of Computer Science, George Mason University

Making Shapes Easily Foldable

Abstract: In recent year, we have witnessed the acceleration in the development of computational origami or origami engineering due to the advances in robotics and material science. For example, self-folding robots can fold itself into a desired shape via the micro-thick folding actuators or by reacting to various stimuli such as light, heat and magnetic fields. Although the development is still in its early stage, there have already been many applications, such as surgical instruments for minimally invasive surgery, where there is a need for very small devices that can be deployed inside the body to manipulate tissue.

Designing foldable structures that can resume or approximate a single or multiple target shapes requires careful foldability analysis. In this talk, I will talk about the recent progress made by my research group to advance the foldability analysis. I will first introduce the basic ideas in computational origami. I will then discuss computational challenges faced in folding rigid origami, a class of origami whose entire surface remains rigid during folding except at crease lines. To address these challenges, I will present techniques that reuse computation and sample in discrete domain. Finally, I will present recent results on the effort of making 3D shapes not only foldable but also can be folded easily by either machine and human folders.

March 19  Peter Hastings, Associate Professor, School of Computing, DePaul University

Identifying Causal Structure in Scientific Explanatory Essays

Abstract:  Educational standards have put a renewed focus on strengthening students' abilities to construct scientific explanations and engage in scientific arguments. Because evaluating student writing is so time-intensive, people often turn to automatic essay evaluation programs, but these generally rely on shallow measures of word choice and coverage of a topic. Such methods can produce an overall, holistic evaluation of the essay quality, but do not reveal the individual connections between causes and effects that students make. Our focus is on determining the causal structure in students' explanations of scientific phenomena, so that we can provide feedback which will help them improve their explanation-writing skills.  Using hand-annotated essays from thousands of high school students in the Chicago area, we have developed machine learning techniques to identify both the conceptual elements in student essays and the causal connections between them.  This talk will describe the techniques that we have used and our evaluation of them.

March 5  Bernadette Mullins, Professor of Mathematics, Chair of Wadsworth Area, Birmingham-Southern College

The Josephus Problem

Abstract: During the Jewish-Roman war in the first century of the Common Era, legend tells us that Josephus was one of 41 Jewish soldiers trapped by the Romans in the fortress of Masada. The soldiers found suicide preferable to dying at the hands of their enemies, so they agreed to form a circle and eliminate every other person until none remained. If you were Josephus, where would you position yourself within the circle, if you wanted to be the last one alive and attempt an escape? We will investigate this question and extensions that could be pursued as an undergraduate research project.

February 28  Ryan Cordell, Assistant Professor of English, and David Smith, Assistant Professor of Computer & Information Science, Northeastern University

Speculative Bibliography: Probabilistic Texts, Page Maps, and Propagation Networks

Absract: The era of mass digitization seems to provide a mountain of source material for digital scholarship, but its foundations are constantly shifting. Selective archiving and digitization obscures data provenance, metadata fails to capture the presence of texts of mutable genres and uncertain authorship embedded within the archive, and automatic optical character recognition (OCR) transcripts contain word error rates for newspapers above 40%. Beyond these issues, even the identity of any given transcription might change due to improved image processing or upgraded OCR. The condition of the mass-digitized text is thus closer to the manuscript sources of an edition than to a scholarly publication.

In this talk, will discuss several aspects of our work on "speculative bibliography" in the Viral Texts Project ( as applied to multi-authored, generically hybrid nineteenth-century newspapers. After briefly summarizing the work of the Viral Texts project, we will discuss an archaeology for tracing the provenance of digitized historical newspapers. We will then discuss methods exploiting the redundancy and cluster structure in these archives to improve OCR accuracy using multi-input attention models and unsupervised learning. We will then demonstrate what page layout analysis can tell us about the evolution of particular newspapers, as well as broader patterns in publishing. We will conclude with a model for inferring frequent communication paths among newspapers.

This talk is cosponsored with the Digital Humanities Faculty Learning Community.

November 27 – Robin Givens W'06, Professor of Computer Science, Randolph Macon College

Sensor Placement Problems: Mixed-Weight OLD-sets

Abstract: The mixed-weight OLD-set problem models a situation in which sensors of different strengths, and potentially different costs, are placed strategically throughout a system to detect and locate issues that may arise.  These problems have applications in a variety of areas including wireless sensor networks, multiprocessor systems, public works and utilities, and other networked systems.  We model a system as a graph and study the optimal placement of sensors using properties in graph theory and algorithmic methods.  This talk introduces mixed-weight OLD-sets and discusses our recent results including an integer linear program and greedy algorithms for finding mixed-weight OLD-sets.

November 13 – Suzanne Robertson, Assistant Professor, Department of Mathematics and Applied Mathematics,Virginia Commonwealth University

Modeling and Control of Enzootic West Nile virus Transmission: Incorporating Avian Stage-dependent Vector Exposure

Abstract: West Nile virus (WNV) is a major public health concern in the United States. While seasonal WNV outbreaks have been widely observed to be associated with the end of the avian nesting season, the ecological mechanisms responsible for this synchronicity are poorly understood. Newly hatched birds, or nestlings, have less feather coverage and fewer defense mechanisms than older birds, rendering them more vulnerable to mosquitoes. While total avian population size increases throughout the season, nestling abundance declines at the end of the brooding season. We investigate how this temporal variation in host stage abundance may structure enzootic WNV transmission with a novel mathematical model incorporating avian (host) stage-structure and within-species heterogeneity in the form of stage-specific mosquito (vector) biting rates. We determine the extent to which temporal fluctuations in host stage and vector abundance throughout the season, along with the differential exposure of these stages to mosquito bites, affects the timing and magnitude of WNV activity as well as implications for public health interventions. Specifically, we explore the viability of nestling vaccination as a new form of control in addition to the widely used controls of mosquito larvicide and adulticide.

October 30  Craig Larson, Associate Professor, Department of Mathematics and Applied Mathematics, Virginia Commonwealth University

The Graph Brain Project

Abstract: We discuss the use of modern computer tools and resources to systematically advance our shared mathematical goals. In this talk we will discuss the available tools in the context of a summer 2017 project to find bounds for the independence number of a graph. The independence number is the cardinality of a maximum independent set in a graph. Two conjectured theorems will be discussed, together with a selection of three interesting open conjectures.

October 9 Dr. Rachel Cummings, Georgia Institute of Technology

The Price of Privacy: Experimental Evidence for the Value of Privacy

Abstract: Privacy is more than a mathematical construct; it exists in real-world settings, and its guarantees are impacted by human perceptions and reasoning.  Practical valuations of privacy can be highly complex, and human reasoning about privacy need not match theoretical models.  We measure people's willingness to pay for privacy, through a series of multi-player behavioral experiments where we vary the information that players see about the actions of others. In each session, many pairs of participants play a Dictator Game in the same room. After all decisions are made, we reveal a noisy signal about the Dictator's contribution to their partner that is correct with some (pre-determined) probability, and a random contribution otherwise. By varying the information sharing policy, we can measure how people trade off money for privacy. We show that people's value for privacy does not match the monotone, linear model that is typically assumed in the theoretical privacy literature. This is a joint work with Inbal Dekel, Ori Heffetz, and Katrina Ligett.

September 18  Student Research Presentations

"Deep Learning for Image Classification" - Guanlin He, Ruojing Jia, Yuetong Li, Lillie Mucha, and Tianchang Yang (Advised by Lewis Barnett)
"Residual Networks for Object Detection and Image Classification" - Thang Le and Bilawal Saikh (Advised by Lewis Barnett)
“The Tennis Ball TSP Problem” - Alec Justice (Advised by Doug Szajda)
“Protecting Data With Mandatory Retention Requirements Using Dragchute Encryption” - Rachel Culpepper (Advised by Doug Szajda)
"ATM Pin Sniffing" - Nicholas Wan and Rishabh Jain (Advised by Doug Szajda)
"Stochastic Allocation Algorithms for Organizing Donation​" - Michael Del Casino (Advised by Prateek Bhakta)

September 4  Student Research Presentations

"Simulating Adapting Multi-agent Motions in Partially Unknown Environments Using Reeb Graphs" - Ryan Jennings, Tracy Nguyen, Are Oelsner (Advised by Jory Denny)
"Towards Realizing Group Flocking Motions in Unknown Environments" - David Qin and Aaqil Zakarya (Advised by Jory Denny)
"Poncelet’s Porism" - Raymond Cao, Tongzhou Wang (Advised by Bill Ross)
"Second-Price Auctions, Mechanism Design, and Healthcare" - Devin Chen and Finnegan Hu (Advised by Mike Kerckhove)
“A Model for the Diffusion of Innovations" - Hassan Naveed and Ran Yan (Advised by Mike Kerckhove)