Skip to main content

Applied and Computational Mathematics Seminar

Applied Math Seminar

Title:  Linearized Krylov subspace Bregman iteration with nonnegativity constraint

Abstract: Bregman-type iterative methods have attracted considerable attention

in recent years due to their ease of implementation and the high quality of the

computed solutions they deliver. However, these iterative methods may 

require alarge number of iterations and this reduces their attractiveness. This talk

describes a linearized Bregman algorithm defined by projecting the 

problem tobe solved into an appropriately chosen low-dimensional Krylov subspace. The projection reduces both the number of iterations and the computational  effort required for each iteration. A variant of this solution method, in which nonnegativity of each computed iterate is imposed, also is described. 

The talk presents joint work with A. Buccini and M. Pasha.
Date:
-
Location:
POT 745
Tags/Keywords:

Applied Math Seminar

Title: Efficient control methods for stochastic Boolean networks

Abstract: The development of efficient methods for finding intervention strategies that can direct a system from an undesirable state into a more desirable state is an important problem in systems biology. The identification of potential interventions can be achieved through mathematical modeling by finding appropriate input manipulations that represent external interventions in the system. This talk will describe a stochastic modeling framework generalized from Boolean networks, which will be used to formulate an optimal control problem. The optimal control method requires a set of control inputs, each representing the silencing of a gene or the disruption of an interaction between two molecules. Several methods from Markov decision processes can be used to generate an optimal policy that dictates the action to be taken at each state. However, the computational complexity of these algorithms limits the applications of standard algorithms to small models. This talk will discuss alternate methods that can be used for large models.

Date:
-
Location:
POT 745
Tags/Keywords:

Applied Math Seminar

Title: Enhancing mechanistic modeling with machine learning

Abstract: At their core, biological systems are information processing systems. In response to numerous environmental cues, the complex molecular interaction networks within human cells integrate these signals and orchestrate a number of intricate cellular behaviors. Verbal argument and intuition alone are insufficient to understand how these complex networks control cellular behaviors or to rationally design treatment, and it is beneficial to translate these molecular networks into realistic and predictive mathematical models. However, the development of such models faces several fundamental challenges: 1) the control network is complex and full of interacting feedbacks, 2) the kinetic constants characterizing the biological reactions are often unavailable, 3) it is often impossible to derive analytical solutions of these models, and 4) once the models become increasingly realistic and complex, they are often as difficult to understand as the original biological system. To address these above mentioned challenges, we have developed an integrated computational pipeline that combines Mechanistic modeling, Machine learning and nonlinear dynamical analysis. By integrating different methods with unique strength and limitations, this innovative pipeline can potentially overcome each other’s limitations. This novel, integrated pipeline has been applied to study several different biological systems, and the results have been verified experimentally. Based on our theoretical analysis and experimental confirmation, we propose that his novel pipeline can be generally applied to understand any complex and uncertain biological systems.

Date:
-
Location:
POT 745
Tags/Keywords:

Applied Math Seminar

Title: Recovering data sparse in a frame

Abstract: In this talk, we will first review some classical results on compressed sensing, a subject about recovering sparse signals from undersampled linear measurements. The theory developed in compressed sensing is transformative as it has been applied to a broader class of data recovery problems such as matrix completion. Then we will focus on its generalization where signals are sparse in a redundant frame. We will discuss the challenges faced in this case, as well as some new results. A preliminary image inpainting application will also be addressed at the end of the talk.

Date:
-
Location:
POT 745
Tags/Keywords:

Applied Math Seminar

Title: Information Theoretic Learning with Infinitely Divisible Kernels

Abstract: In this work, we introduce a framework for information theoretic learning based on an entropy-like functional defined on positive definite matrices. The proposed functional, which is based on Renyi's axiomatic definition of entropy, provides a quantity that can be estimated from data and applied as an objective function in different machine learning problems. As an application example, we derive a supervised metric learning algorithm using a matrix-based analogue to conditional entropy with results comparable with the state of the art.

Date:
-
Location:
POT 745
Tags/Keywords:

Applied Math Seminar

Title: Particle collision model embedded into an optimization graph theory problem.

Abstract: The color reconnection model is used to explain and predict the production of particles in high energy collisions of hadrons.  According to this model, the colored partons produced in an event  can lose their original color quantum numbers and acquire new ones if this reduces a type of free energy. The computation of the  ground state of the free energy is combinatorially complex.  In this note, we demonstrate the limitations of traditional techniques for solving this problem and the possibility of using quantum solvers.   In particular, we present an Ising model formulation for quantum annealers and a gate-based formulation.

During my time at FermiLab, given by the MSGI-NSF program, I was able to jump in on this problem to help construct an optimal Hamiltonian for quantum annealers. I will be providing an introduction to the physics problem and my contribution in how we used AMPL to help us construct a Hamiltonian.

Date:
-
Location:
POT 745
Tags/Keywords:

Applied Math Seminar

Title: Generative Adversarial Networks
 
Abstract: ​In 2014, Ian Goodfellow et al. proposed a new framework for estimating generative models via an adversarial process, in which we simultaneously train two models: a generative model G that captures the data distribution, and a discriminative model D that estimates the probability that a sample came from the training data rather than G. The training procedure for G is to maximize the probability of D making a mistake. In this talk, I will talk about the structure of such a framework, how we train it as well as some theoretical results and applications.
Date:
-
Location:
POT 745
Tags/Keywords:

Applied Math Seminar

Title: Algebraic Data Science 

Abstract:  Data science has emerged as an important field for making decisions based on data collected from sectors as varied as health care and housing. Two important steps in a data-science pipeline are data collection strategies and predictive modeling.  In this talk, we introduce an algebraic-geometric platform for unifying experimental design for discrete data sets and model selection for polynomial dynamical systems.  We will illustrate the utility of the platform on a few biological systems.

 

 

Date:
-
Location:
POT 745
Tags/Keywords:

Applied Math Seminar

Title: Parameter space analysis and automatic theorem proving in SageMath
Abstract: A metaprogramming trick transforms algebraic programs for testing a property for a given input parameter into programs that compute semialgebraic descriptions of the input parameters for which the property holds. Our implementation of this trick is for the Python-based computer algebra system SageMath. We borrow techniques from global optimization for simplification of semialgebraic sets. We investigate practical representations of proof cells and efficient strategies that lead to shorter proofs. We illustrate it with an application to the theory of integer linear optimization, the automatic discovery and proof of certain cutting plane theorems in integer programming.
Date:
-
Location:
POT 745
Tags/Keywords:

Applied Math Seminar

Title: On the Real-time Learning-based Control of Dynamical Systems

Abstract: Understanding actuation mechanisms, sensing systems, and behavior patterns of humans has been a subject of scientific inquiry for centuries. The brain is arguably the most important organ in the human body. It controls and coordinates actions and reactions, allows us to think and feel, and enables us to have memories and feelings-all the things that make us human. In most applications, controllers are not designed after humans. In general, unique applications in controls require custom controller designs based on systems information. This becomes problematic when there are un-modeled disturbances and/or full knowledge of the system dynamics is not available, etc., if we can mimic human behavior, this allows us to adaptively learn the control law without a priori knowledge about the system dynamics. To mimic human behavior, we must explore methods that can adapt to unknown environments with minimal system information. However, limitations include insufficient data a priori, computational complexity of learning algorithms, and lack of methods for real-time implementation of said algorithms, etc. We will overcome these challenges by considering real-time learning-based methods. I will present the Emotional Learning and Neural Network (-based) approaches for utilization in real-time control of unknown dynamical systems. Specifically, we will demonstrate applications in Robotic, Power Systems, and Process Industries.

Date:
-
Location:
POT 745
Tags/Keywords: