Skip to main content

Applied and Computational Mathematics Seminar

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:

Applied Math Seminar

Title: Correct Model Selection in Big Data Analysis



Abstract: Although recent attention has focused on improving predictive models, less consideration has been given to variability introduced into models through incorrect variable selection. Here, the difficulty in choosing a scientifically correct model is explored both theoretically and practically, and the performance of traditional model selection techniques is compared with that of more recent methods. The results in this talk show that often the model with the highest R-squared (or adjusted R-squared) or lowest Akaike Information Criterion (AIC) is not the scientifically correct model, suggesting that traditional model selection techniques may not be appropriate when data sets contain a large number of covariates. This work starts with the derivation of the probability of choosing the scientifically correct model in data sets as a function of regression model parameters, and shows that traditional model selection criteria are outperformed by methods that produce multiple candidate models for researchers' consideration. These results are demonstrated both in simulation studies and through an analysis of a National Health and Nutrition Examination Survey (NHANES) data set.

Date:
-
Location:
POT 745
Tags/Keywords:

Applied Math Seminar

Title: Modeling the emergence of Division of labor in social systems

 

Abstract: Division of labor (DOL) is a key pattern of social organization that has evolved in a diverse array of systems from microbes, insects and, of course, humans.  Theoretical models predict that division of labor is optimal (and that evolutionary selection can favor it) if there are increasing efficiency (or fitness) benefits arising from individual specialization. One main open question about DOL is ‘What proximate (behavioral) mechanisms are responsible for its initial emergence?’ In this talk, I will propose a novel theory using a framework of individual energetics and optimization in social dynamics. The key assumption is that individuals are myopic optimizers of a utility function that reflects the tradeoffs of energy/ time needed to perform, and become proficient in, a set of alterative (fitness-bearing) tasks. This hypothesis serves as counterpoint to existing theory of inter-individual variation in “response thresholds” popularized by studies of task allocation in social insect colonies.  Simulation findings show that DOL can emerge from individual optimization and can be enhanced by varying parameters of fatigue and group size. This result has broader implications for understanding the evolutionary transition to sociality (the period in which previously solitary animals began living together in groups).

Date:
-
Location:
POT 745
Tags/Keywords:

Applied Math Seminar

Title: Intermittent Preventive Treatment and the Spread of Drug Resistant Malaria

Abstract: Over the last decade, control measures have significantly reduced malaria morbidity and mortality. However, the burden of malaria remains high, with more than 70% of malaria deaths occurring in children under the age of five. The spread of antimalarial resistant parasites challenges the efficacy of current interventions, such as Intermittent Preventive Treatment (IPT), whose aim it is to protect this vulner- able population. Under IPT, a curative dose of antimalarial drugs is administered along with a child’s routine vaccinations, regardless of their infection status, as both a protective measure and to treat subclinical infections. We have developed mathematical models to study the relative impact of IPT in promoting the spread of drug resistant malaria (compared with treatment of clinically ill individuals), and the combined effect of different drug half-lives, age-structure and local transmis- sion intensity on the number of childhood deaths averted by using IPT in both the short and long-term in malaria endemic settings. I will also discuss some potential consequences of unstable and seasonal transmission of malaria on the efficacy of IPT.

Date:
-
Location:
POT 745
Tags/Keywords:

Applied Math Seminar

Title: Exponential convergence rates for Batch Normalization

Abstract: Batch Normalization is a normalization technique that has been used in training deep Neural Networks since 2015. In spite of its empirical benefits, there exists little theoretical understanding as to why this normalization technique speeds up learning. From a classical optimization perspective, we will discuss specific problem instances in which we can prove that Batch Normalization can accelerate learning, and how this acceleration is due to the fact that Batch Normalization splits the optimization task into optimizing length and direction of parameters separately. 

 

Date:
-
Location:
POT 715
Tags/Keywords:
Subscribe to Applied and Computational Mathematics Seminar