Faculty Research Talks - Fall 2022
Talks will be held at 2:30PM on every other Monday (M) at 2:30PM in CULM 611 unless otherwise noted. Please see more information below:
September 19
Location: CULM 111
Soft Matter Systems: Big-data, Networks, Topology, Machine Learning
This project focuses on modeling soft matter systems using the methods that include modeling, discrete element simulations, network analysis using computational topology methods, and machine learning. The considered setups are typical for big-data problems involving large amount of dynamical data. The plan is to use various mathematical methods to simplify these data sets with focus on extracting physical mechanisms governing the behavior of underlying systems. The systems of interest include wet and dry granular matter that are of relevance to a number of soft matter systems such as suspensions including active matter ones, among others.
The part of the project at NJIT focuses on modeling and simulations, and will be carried out in close collaboration with another modeling group at the Levich Institute at City College of New York, a group at Rutgers University focusing on topological methods, and a group at Oklahoma University implementing machine learning techniques.
The presentation will provide an overview of various approaches being used, as well as of specific problems that have been explored recently. In addition, we will briefly discuss few other projects that are currently considered by Complex Flow and Soft Matter Group members; more information about current and past projects can be found at the group page, cfsm.njit.edu.
October 3
Professor Chong Jin
Location: CULM 111
Integrating Multi-omics Summary Data Using a Mendelian Randomization Framework
Using Mendelian randomization, we can identify the possible causal relationship between an omics biomarker and disease outcome using genetic variants as instrumental variables. This allows us to prioritize genes whose omics readouts can be used as predictors of the disease outcome through analyzing GWAS and QTL summary data. However, best practices are elusive when jointly analyzing the effects of multiple -omics biomarkers annotated to the same gene of interest. To bridge this gap, we propose powerful combination tests that integrate multiple correlated p-values without knowing the dependence structure between the exposures. Our simulation experiments demonstrate the superiority of our proposed approach compared with existing methods adapted to the setting of our interest. The method is illustrated on a multi-omics Alzheimer's disease dataset.
October 17
Location: CULM 611
Centrosome Dynamics Driven by Collective Pulling Forces from Cortical Force Generators
Centrosome is the main microtubule organization center (MTOC) that regulates cell adhesion, motility and cell division through the collective dynamics of motor proteins and microtubules that nucleate on the centrosome. In the past it was argued that both pulling and pushing forces from the microtubules are needed for centrosome positioning in different geometry of confinement. Over the years this paradigm has been challenged in many different ways. In this study we show that, through a coarse-grained model that captures the stoichiometric interactions between microtubules and motor proteins, pulling forces alone are sufficient for centrosome centering and various centrosome dynamics observed in the experiments. We also show, both analytically and numerically, how various centrosome dynamics may be explained through this coarse-grained model. This is a collaboration with Reza Farhadifa and Michael Shelley at the Center for Computational Biology at Flatiron Institute, part of Simons Foundation.
October 24
Professor Kristina Wicke
Location: CULM 611
The Mathematics of Evolution – An Introduction to Mathematical Phylogenetics
Phylogenetics is the study of the evolutionary history and relationships among different organisms. Originally a subfield of biology, this area of research has given rise to a variety of mathematical and computational problems over the last few decades. It involves various disciplines, ranging from combinatorics and graph theory to probability and statistics to algebra and computer science.
In this talk, I will give a broad introduction into the area of mathematical phylogenetics, before illustrating some specific problems related to my own research interests, for instance the balance of phylogenetic trees, the application of phylogenetic trees to biodiversity conservation, and the study of phylogenetic networks. Rather than focusing on technical details, the aim of this talk is to showcase which kinds of problems arise in phylogenetics and which approaches are used to solve them. This talk assumes no background in biology, and all are welcome.
November 14
Professor Thi-Phong Nguyen
Location: CULM 611
Direct and Inverse Scattering Problems in Locally Perturbed Periodic Media
In this talk, I will discuss some efficient numerical methods for solving both direct and inverse scattering problems in locally perturbed periodic media as well as some open questions (potential projects).
Roughly speaking, the direct scattering problem aims to solve a Helmholtz equation (PDE) numerically. The proposed method, namely spectral method, is based on Floquet-Bloch transform in the periodicity direction of the background of the media and spectral method in the space variable. The discretization in Floquet-Bloch variable provides a coupled quasi-periodic system, where the resolution of each individual equation exploits a volumetric reformulation of the problem in only one period and a periodization of the kernel in the direction orthogonal to the periodicity.
The inverse problems is dedicated to identify local defects (their shapes and locations) in an unknown periodic media using the scattered waves that measured at certain distance. We develop the so-called Differential Sampling Method, based on classical Sampling methods, for this task. The principle of the method is to build an indicator function that is able to indicate whether or not an arbitrary sampling point is inside or out side the defects.
December 5
Location: CULM 611
Title: TBA
Abstract: TBA
Updated: November 28, 2022