Stony Brook University Applied Mathematics and Statistics

Speaker: Jinsoo Hwang   Location: B105 Date and Time: April 22 (Mon), 6:30 PM - 7:30 PM in KST About the Speaker: Dr. Jinsoo Hwang Adjunct Professor, Dept. of Applied Mathematics and Statistics | SUNY Korea Dean, College of Natural Sciences | Inha University Assistant Professor, Department of Mathematical Sciences | Arizona State University Ph.D. in Statistics | Purdue University M.S. in Statistics | Seoul National University B.S. in Statistics & Computer Science | Seoul National University Abstract Detecting ransomware is harder than general malware because of the ever-increasing number of ransomwares with different signatures, which makes traditional signature-based detection technique powerless against ransomware. Current ransomware detection techniques usually build a complex model that incorporates various behavioral traits. The traits include suspicious file activities, API call pattern or frequency, registry keys, file extensions, etc. In this paper, we build a two-stage mixed ransomware detection model, Markov model and Random Forest model. First, we focus on Windows API call sequence pattern and build a Markov model to capture the characteristics of ransomware. Next, we build Random Forest machine learning model to the remaining data to control both false positive (FPR) and false negative (FNR) error rates. As a result of our two-stage mixed detection method we can achieve overall accuracy 97.3% with 4.8% FPR and 1.5% FNR.    

[Spring 2024 AMS Seminar I] A Numerical Conversion from Multiple Decrement Rates to Absolute Rates of Decrements by Prof. Taewon Lee  

Speaker: Taewon Lee   Location: B105 Date and Time: March 25 (Mon), 6:30 PM - 7:30 PM in KST   About the Speaker: Dr. Taewon Lee - (Current) Visiting Professor, Dept. of Applied Math and Statistics, SUNY Korea - Professor, Division of Applied Mathematical Sciences, Korea University, Sejong Campus - Visiting Scholar, Dept. of Statistics and Actuarial Science, University of Waterloo - Ph.D. in Applied Mathematics and Statistics, State University of New York at Stony Brook - MS in Statistics, Seoul National University - BS in Mathematics, Seoul National University   Abstract Modeling interactions of competing risks affecting the occurrence of various decrements such as death or disease is a critical issue in survival analysis and actuarial science. It is essential to incorporate multiple decrements for offerring various coverages in an insurance contract. Popular assumptions for the construction of decrement models are uniform distributions of decrements (UDD) in a multiple decrement table (MDT) and associated single decrement tables (ASDT). Whereas the conversion from absolute rates of decrements in ASDT to multiple decrement rates in MDT under the UDD assumption has an explicit formula, extracting absolute rates from multiple decrement rates becomes solving a system of non-linear equations. A novel numerical algorithm using a fixed point iteration method for searching a solution of the system of equations is proposed. The proposed numerical algorithm to obtain absolute rates of decrement from observed probabilities of decrement makes it possible to estimate a new multiple-decrement table from an old multiple-decrement table with some risk factors to be removed. The algorithm delivers reliable results in terms of efficiency and accuracy. The proposed algorithm is proved to be a stable algorithm that never diverges out of range of probability during the iterations. The self-mapping property in iteration is expected to lead to prove the existence of a solution of the system of equations.  

Welcome aboard, the class of 2028! Congratulations and best wishes on your first semester!  

We have been hosting the Math Competition since 2016. After a pause due to the COVID-19 pandemic, we are thrilled to resume this event. It is wonderful to have this event reactivated and to meet the outstanding students once again.   We had 38 high school students, from 24 different high schools, and 27 SUNY Korea students, not only from the College of Engineering and Applied Sciences from SBU but also from the Fashion Design Department from FIT.    Thank you for all your participation. We’d like to express our sincere congratulations to all the winners! Hope to see more students from various high schools and also from all different departments at SUNY Korea next year.   [Pic.1] 2023 Math Competition Award Ceremony for the winners of 2023! (12/02/2023)   [Pic.2] A Short Lecture delivered by Prof. Hongshik Ahn before the Math Competition (11/23/2023)

SUNY Korea Admissions Team hosted the 2023 SUNY Korea Experience Day on November 25, welcoming all prospective and admitted students. Prof. Hongshik Ahn provided an introduction about the AMS Department, and Prof. Young-Seon Lee gave a mock lecture on the topic of 'Essential Concepts of Integral Calculus' to the students. The Experience Day will be held every semester. All prospective students are welcome to the event. Hope to see many students next year again! Introduction of the AMS Department by Prof. Hongshik Ahn   Mock Lecture <Essential Concepts of Integral Calculus> by Prof. Young-Seon Lee

Fall 2023 AMS Seminars -> Seminar II, Hierarchical Bayesian Spatial Regression Models by Prof. Jaewoo Park from Yonsei University.     -> Seminar III, Accelerated Failure Time Modeling via Nonparametric Mixtures by Prof. Sangwook Kang from Yonsei University.   There will be more interesting seminars coming up next semester, so stay tuned! :) 

Speaker: Sangwook Kang   Location: B105 Date and Time: November 20 (Mon), 10:30 AM - 11:30 AM in KST About the Speaker: Dr. Sangwook Kang - (Current) Professor and Chair, Dept of Applied Statistics, Yonsei University -  Assistant/Associate Professor, Dept of Applied Statistics, Yonsei University -  Visiting Professor, Dept of Statistics, University of Connecticut -  Associate Director, Yonsei Institute of Data Science, Yonsei University -  Assistant Professor, Dept of Statistics, University of Connecticut -  Assistant Professor, Dept of Epidemiology and Biostatistics, University of Georgia Abstract An accelerated failure time (AFT) model assuming a log-linear relationship between failure time and a set of covariates can be either parametric or semi-parametric, depending on the distributional assumption for the error term. Both classes of AFT models have been popular in the analysis of censored failure time data. The semiparametric AFT model is more flexible and robust to departures from the distributional assumption than its parametric counterpart. However, the semiparametric AFT model is subject to producing biased results for estimating any quantities involving an intercept. Estimating an intercept requires a separate procedure. Moreover, a consistent estimation of the intercept requires stringent conditions. Thus, essential quantities such as mean failure times might not be reliably estimated using semiparametric AFT models, which can be naturally done in the framework of parametric AFT models. Meanwhile, parametric AFT models can be severely impaired by misspecifications. To overcome this, we propose a new type of the AFT model using a nonparametric Gaussian-scale mixture distribution. We also provide feasible algorithms to estimate the parameters and mixing distribution. The finite sample properties of the proposed estimators are investigated via an extensive stimulation study. The proposed estimators are illustrated using the well-known PBC dataset.

Speaker: Jaewoo Park   Location: B105 Date and Time: October 30 (Mon), 6:40 PM - 7:40 PM in KST RSVP HERE: https://forms.gle/SJeFVFSNsZRD2yfVA About the Speaker: Dr. Jaewoo Park -  (Current) Assistant Professor, Department of Applied Statistics, Yonsei University -  Ph.D. in Statistics, The Pennsylvania State University -  BA in Applied Statistics, Economics, Yonsei University Abstract Spatial regressions are widely used to study relationships between spatial variables in many scientific domains, such as ecology, epidemiology, and sociology. For a given spatial latent process, hierarchical structures are defined for building complex high-dimensional models from simple and low-dimensional building blocks. Bayesian approaches are popular for hierarchical spatial models due to their computational and inferential advantages. In this talk, I will review the Bayesian framework for hierarchical spatial regression models. I will show how such models can be applied to real datasets, such as confirmed COVID-19 cases in the United States.

Speaker: Thieu Nguyen   Location: B105 Date and Time: September 25 (Mon), 6:40 PM - 7:40 PM in KST RSVP HERE: https://forms.gle/GiLkAd6fvrdMSGH29 About the Speaker: Dr. Thieu Nguyen -  (Current) Institute of Mathematics, Vietnam Academy of Science And Technology, Hanoi, Vietnam -  Ph.D. in Applied Mathematics, University of Limoges, France -  MS in Mathematics, University of Limoges, France -  MS in Mathematics, Institute of Mathematics, Vietnam -  BS in Mathematics, Vietnam National University Abstract This talk serves as an introductory overview of generalized differentiation. We will present the concepts of generalized differentiation and their applications in optimization and optimal control. Firstly, we will revisit the definition of classical differentiability and explore some related results in optimization problems. Then, we will delve into nonsmooth techniques designed for scenarios where classical differentiation is inapplicable. Lastly, we will discuss the applications of these principles in optimal control and introduce some ongoing research problems.      

The Department of Applied Mathematics and Statistics (AMS) at SUNY Korea seeks applicants for multiple tenure track and non-tenure-track faculty positions in the area of mathematics, applied mathematics or statistics at all levels, starting spring of 2024 or fall 2024. 

Congratulations to all of our proud class of Spring 2023!  Besides the students who attended today's SUNY Korea commencement, we would also like to express our congrats to all SUNY Korea AMS students graduating from Stony Brook New York Campus. Please join us in congratulating the class of Spring 2023 listed below. Master of Science Juan Kim Solha Park Su Hyun Shin Bachelor of Science Dajung Choi, Cum Laude Seung Won Han Yeji Kim, Magna Cum Laude Haejoon Lee, Summa Cum Laude Juyoung Lee, Cum Laude Leah Nabangi Ji Woo Park Seoyun Park, Magna Cum Laude Jihye Yang ​​​​​​​ Well done and wish you all the best on your new journey!!

Speaker: Jiangdong Ai  Venue: B103 Date and Time: May 22 (Mon), 6:30 PM - 7:30 PM in KST RSVP HERE: https://forms.gle/nLJsmjp8Y6JtaXG37 About the Speaker  -  (Current) Postdoctoral Research Fellow, SUNY Korea -  Postdoctoral Research Fellow, Royal Holloway, University of London, UK -  Ph.D. Candidate in Computer Science, Royal Holloway, University of London, UK -  BS in Math and Applied Math, Beijing University of Chemical Technology, China -  Research interest: Colorings of digraph; the generalization and improvement of some                              conclusions in undirected graphs in directed graphs; the proof or                              promotion or refutation of certain conjectures; for the basic properties                             of directed hypergraphs, including Hamiltonian, King, and so on. Abstract Graph theory is an area which connects the elegance of painting and the rigor of mathematics; It is simple, but not unsophisticated. Graph Theory gives us, both an easy way to pictorially represent many major mathematical results, and insights into the deep theories behind them.    

Speaker: Dr. Sehun Chun  Venue: B105 Date and Time: April 24 (Mon), 6:30 PM - 7:30 PM in KST RSVP HERE: https://forms.gle/xdcvA7r5baVyPoabA About the Speaker  -  (Current)  Assistant Professor of Applied Mathematics, UIC, Yonsei University, Incheon -  Residential Researcher, African Institute for Mathematical Sciences, Cape Town, South Africa -  Research Associate, Imperial College London, London, UK -  Research Assistant, Brown University, Providence, US -  Ph.D. in Applied Mathematics, Brown University -  M.S. in Applied Mathematics, Brown University & in Mathematics, Purdue University -  BS in Mech. & Aero Engineering, Seoul National University -  Research interest: Electrodynamics, Moving Frames, Curved surfaces, Electrophysiology, Cardiology, Neuroscience Abstract Recent advances in artificial intelligence (AI) have drawn unprecedented attention from every corner of our society. This presentation focuses on AI based on neural network algorithms. These algorithms derive from the study of a small region or function of the brain, particularly regarding vision. Their implications are almost limitless in the modern era but only a handful of applications survive, leaving other applications incomplete or inferior. Thus, we should pay attention to what is missing in AI algorithms compared to the real human brain before being overwhelmingly pessimistic about AI. Among the critical factors which will limit AI functionalities, we focus on the unique structure and distribution of neural fibers within a small volume of the brain, called the geometry of intelligence. The geometry of intelligence may explain the secret behind superior data processing efficiency and the mysterious entanglement with our physical world. The study of the geometry of intelligence can shed light on a possible breakthrough with respect to the current critical flaws of AI, or at least help us better understand the boundaries of AI for constructive and safe applications.   

Haejoon Lee has been admitted to the Ph.D. program in Robotics at the University of Michigan. Haejoon will be receiving 5-year guaranteed funding.  Haejoon will graduate in Spring 2023 with a bachelor's degree in applied mathematics and statistics and a minor in computer science.  Please join us in congratulating Haejoon Lee on the successful beginning of his Ph.D. program!