Latest revision as of 19:12, 26 October 2022

Mondays at 4pm EDT
Armstrong Hall 315 zoom link (pass euclid2022)

The 2022-2023 WVU Math Colloquium is organized by Chris Ciesielski, Robert Mnatsakanov and Casian Pantea. Talks are usually held on Mondays at 4pm in Armstrong Hall 315 (in some cases we will schedule the seminar at different days/times, to accommodate speakers).

If you'd like to suggest speakers for the fall semester please contact Chris, Robert, or Casian.

Schedule

date	speaker	institution	title	notes
September 15	Dehua Wang	University of Pittsburgh	Elastic effects on vortex sheets and vanishing viscosity	2:30pm, 315 ARM
October 17	Farhad Jafari	University of Minnesota	Variational Problems, Moment Sequences and Positive Definiteness
October 24	Tóth János	Budapest University of Technology and Economics	The concept of reaction extent
October 31	Zi-Xia Song	University of Central Florida	Coloring Graphs with Forbidden Minors
November 14	Benjamin Bagozzi	University of Delaware	Understanding the Politics of Information Access in Big Data Contexts

Abstracts

Dehua Wang

Elastic effects on vortex sheets and vanishing viscosity

Elasticity is important in continuum mechanics with a wide range of applications and is challenging in analysis. In this talk we shall first review some basic mathematical results and then discuss some special elastic effects in fluid flows. The first elastic effect is the stabilizing effect of elasticity on the vortex sheets in compressible elastic flows. Some recent results on linear and nonlinear stability of compressible vortex sheets will be presented. The second effect is on the vanishing viscosity process of compressible viscoelastic flows in the half plane under the no-slip boundary condition. Our results show that the deformation tensor can prevent the formation of strong boundary layers. The talk is based on the recent joint works with several collaborators.

Farhad Jafari

Variational Problems, Moment Sequences and Positive Definiteness

Our ability to reformulate many problems in science and engineering in terms of variational (and control) problems continue to keep this area of mathematics current and of great interest. In this presentation we reformulate these problems as problems in measure theory and use moment methods to study them. Relating variational problems to moment methods has brought new interest in moment methods, moment completion problems and algebras of rational functions. This talk will connect these areas and (briefly) will show applications of moment methods to reconstruction problems in tomography.

Tóth János

The concept of reaction extent

The concept of reaction extent or the progress of a reaction, advancement of the reaction, conversion, etc. was introduced around 100 years ago. Most of the literature provides a definition for the exceptional case of a single reaction step or gives an implicit definition that cannot be made explicit. Starting from the standard definition we extend the classic definition of the reaction extent in explicit form for an arbitrary number of species and of reaction steps and arbitrary kinetics. Then, we study the mathematical properties (evolution equation, continuity, monotony, differentiability, etc.) of the defined quantity, and connect them to the formalism of modern reaction kinetics. Our approach tries to adhere to the customs of chemists and be mathematically correct simultaneously.

We also show how to apply this concept to exotic reactions: reactions with more than one stationary state, oscillatory reactions, and reactions showing chaotic behavior. With the new definition, one can calculate not only the time evolution of the concentration of each reacting species but also the number of occurrences of the individual reaction events.

This is joint work with Vilmos Gáspár.

Zi-Xia Song

Coloring Graphs with Forbidden Minors

Abstract link

Benjamin Bagozzi

Understanding the Politics of Information Access in Big Data Contexts

Access to information (ATI) systems empower groups and individuals to request information from their governments and obligate these governments to respond, subject to certain legal exemptions. These systems are now in operation in over 100 countries worldwide. The data that are generated by ATI systems can often be characterized as having (i) fine-grained spatio-temporal properties, (ii) extensive amounts of text, (iii) sender-receiver characteristics, and (iv) potential privacy concerns. For political science, such data offer researchers an opportunity to study questions related to government responsiveness, bureaucratic performance, and public accountability at near-unprecedented levels of disaggregation. This presentation highlights the opportunities and challenges associated with ATI data for both data science and political science audiences. Its focus is primarily on Mexico's federal ATI system and over two million associated ATI requests and responses covering the 2003-2020 period. Applications of supervised and unsupervised machine learning tools to the texts of these requests and their responses will be presented, alongside analyses of these request-response measures in relation to government responsiveness in Mexico.

@@ Line 1: / Line 1: @@
-'''Wednesdays at 4pm EDT'''<br />
+'''Mondays at 4pm EDT'''<br /> Armstrong Hall 315
-[https://wvu.zoom.us/j/96317244165?pwd=YVJGWHdxb2lGUHlkZEdRT1NPRFFsUT09 zoom link] (pass ''mathAdi2'')
+[https://wvu.zoom.us/j/91064873237?pwd=R2lMSkpDUHREaU1xeUdDeVJHT2ZaUT09 zoom link] (pass ''euclid2022'')
-The 2021-2022 Applied Mathematics Seminar is organized by Adrian Tudorascu and Casian Pantea.
+The 2022-2023 WVU Math Colloquium is organized by Chris Ciesielski, Robert Mnatsakanov and Casian Pantea.
-The talks are on zoom until further notice. The regular time for the Seminar is on Wednesday at 4:00 p.m. (in some cases we will schedule the seminar at different times, to accommodate speakers).
+Talks are usually held on Mondays at 4pm in Armstrong Hall 315 (in some cases we will schedule the seminar at different days/times, to accommodate speakers).
-If you'd like to suggest speakers for the fall semester please contact Adrian or Casian.
+If you'd like to suggest speakers for the fall semester please contact Chris, Robert, or Casian.
@@ Line 19: / Line 19: @@
 !align="left" | notes
 |-
-|December 1
+|September 15
-| Veronica Ciocanel
+| Dehua Wang
-| Duke University
+| University of Pittsburgh
-|[[#Veronica Ciocanel  |   TBA ]]
+|[[#Dehua Wang  |   Elastic effects on vortex sheets and vanishing viscosity ]]
+| 2:30pm, 315 ARM
 |
 |-
-|November 17
+|October 17
-| Radu Precup
+| Farhad Jafari
-| Babes-Bolyai University
+| University of Minnesota
-|[[#Radu Precup  |   Harnack type inequalities and localization of solutions ]]
+|[[#Farhad Jafari | Variational Problems, Moment Sequences and Positive Definiteness ]]
 |
 |-
-|November 10
+|October 24
-| Jue Wang
+| Tóth János
-| Union College
+| Budapest University of Technology and Economics
-|[[#Jue Wang  |   Locating Objects of Interest from Screening Ultrasound ]]
+|[[#Tóth János  |  The concept of reaction extent ]]
 |
 |-
-|November 3
+|October 31
-| Matthew Johnston
+| Zi-Xia Song
-| Lawrence Technological University
+| University of Central Florida
-|[[#Matthew Johnston  |   A Mathematical Model of COVID-19 Spread by Vaccination Status ]]
+|[[#Zi-Xia Song  |  Coloring Graphs with Forbidden Minors ]]
 |
 |-
-|October 20
+|November 14
-| Xiang Xu
+| Benjamin Bagozzi
-| Old Dominion University
+| University of Delaware
-|[[#Xiang Xu  |   Blowup rate estimates of a singular potential in the Landau-de Gennes theory for liquid crystals ]]
+|[[#Benjamin Bagozzi | Understanding the Politics of Information Access in Big Data Contexts ]]
-|
-|-
-|September 28
-| Lorand Parajdi
-| WVU
-|[[#Lorand Parajdi  |   On the controllability of some systems modeling cell dynamics related to leukemia ]]
-|
-|-
-|September 15
-| Adrian Tudorascu
-| WVU
-|[[#Adrian Tudorascu  |   On the convexity condition for the semi-geostrophic system ]]
-|
 |}
 =Abstracts=
-===Veronica Ciocanel===
+===Dehua Wang===
-TBA
-===Radu Precup===
+'''''Elastic effects on vortex sheets and vanishing viscosity'''''
-Harnack type inequalities and localization of solutions
+Elasticity is important in continuum mechanics with a wide
+range of applications and is challenging in analysis. In this talk we
+shall first review some basic mathematical results and then discuss
+some special elastic effects in fluid flows. The first elastic effect
+is the stabilizing effect of elasticity on the vortex sheets in
+compressible elastic flows. Some recent results on linear and
+nonlinear stability of compressible vortex sheets will be presented.
+The second effect is on the vanishing viscosity process of
+compressible viscoelastic flows in the half plane under the no-slip
+boundary condition. Our results show that the deformation tensor can
+prevent the formation of strong boundary layers. The talk is based on
+the recent joint works with several collaborators.
-First it is explained the problem of localization of solutions for boundary value problems in general. Next, the focus will be on radial solutions for phi-Laplace equations. Numerical solutions are obtained for some concrete equations.
+===Farhad Jafari===
-===Jue Wang===
+'''''Variational  Problems, Moment Sequences and Positive Definiteness'''''
-Locating Objects of Interest from Screening Ultrasound
+Our ability to reformulate many problems in science and engineering in terms of variational  (and control) problems continue to keep this area of mathematics current and of great interest. In this presentation we reformulate these problems as problems in measure theory and use moment methods to study them. Relating variational problems to moment methods has brought new interest in moment methods, moment completion problems and algebras of rational functions.  This talk will connect these areas and (briefly) will show applications of moment methods to reconstruction problems in tomography.
-A fast Enclosure Transform is developed to localize complex objects of interest from medical ultrasound images. This approach explores spatial constraints on regional features from a sparse image feature representation. Unrelated, broken ridge features surrounding an object are organized collaboratively, giving rise to the enclosureness of the object. Three enclosure likelihood measures are constructed, consisting of the enclosure force, potential energy, and encloser count. In the transform domain, the local maxima manifest the locations of interest objects, for which only the intrinsic dimension is known a priori. I will demonstrate two medical applications in detecting (1) suspicious breast masses in screening breast ultrasound, and (2) the location of the prostate on trans-abdominal ultrasound for verification of patient positioning in radiotherapy treatment of prostate cancer.
+===Tóth János===
-===Matthew Johnston===
+'''''The concept of reaction extent'''''
-A Mathematical Model of COVID-19 Spread by Vaccination Status
+The concept of reaction extent or the progress of a reaction, advancement of the reaction, conversion, etc. was introduced around 100 years ago.
+Most of the literature provides a definition for the exceptional case of a single reaction step or gives an implicit definition that cannot be made explicit.
+Starting from the standard definition we extend the classic definition of the reaction extent in explicit form for an arbitrary number of species
+and of reaction steps and arbitrary kinetics. Then, we study the mathematical properties (evolution equation, continuity, monotony, differentiability, etc.) of the defined quantity, and connect them to the formalism of modern reaction kinetics.
+Our approach tries to adhere to the customs of chemists and be mathematically correct simultaneously.
-The novel coronavirus SARS-CoV-2, and the corresponding illness COVID-19, has afflicted hundreds of millions of people worldwide, killed at least 5 million, and devastated the world economy. The rapid development of effective and safe vaccines, which were authorized in the United States under Emergency Use Authorization in December 2020, have offered some hope that the end of the pandemic may be sight; however, at the same time we have seen the rise of variants, such as Delta, which are much more transmissible than the original strains. In this talk, I will introduce an n-stage vaccination model and corresponding system of differential equations which can simulate a disease outbreak by breaking the population down according to their vaccination status. This allows the mitigation effects of vaccination and accelerating effects of variants such as Delta to be uncoupled from one another, and offers valuable insight for the future course of the COVID-19 pandemic. I fit the model to 2021 data from the Virginia Department of Health.
+We also show how to apply this concept to exotic reactions: reactions with more than one stationary state, oscillatory reactions, and reactions showing chaotic behavior. With the new definition, one can calculate not only the time evolution of the concentration of each reacting species but also the number of occurrences of the individual reaction events.
-===Xiang Xu===
-Blowup rate estimates of a singular potential in the Landau-de Gennes theory for liquid crystals
+This is joint work with Vilmos Gáspár.
-The Landau-de Gennes theory is a type of continuum theory that describes nematic liquid crystal configurations in the framework of the Q-tensor order parameter. In the free energy, there is a singular bulk potential which is considered as a natural enforcement of a physical constraint on the eigenvalues of symmetric, traceless Q-tensors. In this talk we shall discuss some analytic properties related to this singular potential. More specifically, we provide precise estimates of both this singular potential and its gradient as the Q-tensor approaches its physical boundary.
+=== Zi-Xia Song===
-===Lorand Parajdi===
+'''''Coloring Graphs with Forbidden Minors'''''
-On the controllability of some systems modeling cell dynamics related to leukemia
+[[Media:SongAbstract.png|'''Abstract link''']]
-In this talk, I will present two control problems for a model of cell dynamics related to leukemia.  The first control problem is in connection with classical chemotherapy, which indicates that the evolution of the disease under treatment should follow a prescribed trajectory assuming that the drug works by increasing the cell death rates of both malignant and normal cells. In the second control problem, as for targeted therapies, the drug is assumed to work by decreasing the multiplication rate of leukemic cells only, and the control objective is that the disease state reaches a desired endpoint. The solvability of the two problems as well as their stability is proved by using a general method of analysis. Some numerical simulations are included to illustrate the theoretical results and prove their applicability. The results can possibly be used to design therapeutic scenarios such that an expected clinical evolution can be achieved.
-===Adrian Tudorascu===
+===Benjamin Bagozzi===
-On the convexity condition for the semi-geostrophic system
+'''''Understanding the Politics of Information Access in Big Data Contexts'''''
-We show that conservative distributional solutions to the Semi-Geostrophic system in a rigid domain are in some well-defined sense critical points of a time-shifted energy functional involving measure-preserving rearrangements of the absolute density and momentum, which arise as one-parameter flow maps of continuously differentiable, compactly supported divergence free vector fields. We also show directly, with no recourse to Monge- Kantorovich theory, that the convexity requirement on the modified pressure potentials arises naturally if these critical points are local minimizers of said energy functional for any admissible vector field.
+Access to information (ATI) systems empower groups and individuals to request information from their governments and obligate these governments to respond, subject to certain legal exemptions. These systems are now in operation in over 100 countries worldwide. The data that are generated by ATI systems can often be characterized as having (i) fine-grained spatio-temporal properties, (ii) extensive amounts of text, (iii) sender-receiver characteristics, and (iv) potential privacy concerns. For political science, such data offer researchers an opportunity to study questions related to government responsiveness, bureaucratic performance, and public accountability at near-unprecedented levels of disaggregation. This presentation highlights the opportunities and challenges associated with ATI data for both data science and political science audiences. Its focus is primarily on Mexico's federal ATI system and over two million associated ATI requests and responses covering the 2003-2020 period. Applications of supervised and unsupervised machine learning tools to the texts of these requests and their responses will be presented, alongside analyses of these request-response measures in relation to government responsiveness in Mexico.

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