Monday, March 15, 2021

2021-03-16 / 12:00 ~ 13:00

학과 세미나/콜로퀴엄 - 대학원생 세미나: Synthetic multistability in mammalian cells

by 정의민()

We will discuss about “Synthetic multistability in mammalian cells”, Zhu et al., bioRxiv (2021) In multicellular organisms, gene regulatory circuits generate thousands of molecularly distinct, mitotically heritable states, through the property of multistability. Designing synthetic multistable circuits would provide insight into natural cell fate control circuit architectures and allow engineering of multicellular programs that require interactions among cells in distinct states. Here we introduce MultiFate, a naturally-inspired, synthetic circuit that supports long-term, controllable, and expandable multistability in mammalian cells. MultiFate uses engineered zinc finger transcription factors that transcriptionally self-activate as homodimers and mutually inhibit one another through heterodimerization. Using model-based design, we engineered MultiFate circuits that generate up to seven states, each stable for at least 18 days. MultiFate permits controlled state-switching and modulation of state stability through external inputs, and can be easily expanded with additional transcription factors. Together, these results provide a foundation for engineering multicellular behaviors in mammalian cells.

2021-03-19 / 10:00 ~ 12:00

학과 세미나/콜로퀴엄 - SAARC 세미나: Understanding Infinite-Width Deep Neural Networks

by ()

Deep neural networks have shown amazing success in various domains of artificial intelligence (e.g. vision, speech, language, medicine and game playing). However, classical tools for analyzing these models and their learning algorithms are not sufficient to provide explanations for such success. Recently, the infinite-width limit of neural networks has become one of key breakthroughs in our understanding of deep learning. This limit is unique in giving an exact theoretical description of large scale neural networks. Because of this, we believe it will continue to play a transformative role in deep learning theory. In this talk, we will first review some of the interesting theoretical questions in the deep learning community. Then we will review recent progress in the study of the infinite-width limit of neural networks focused around Neural Network Gaussian Process (NNGP) and Neural Tangent Kernel (NTK). This correspondence allows us to understand wide neural networks as different kernel based machine learning models and provides 1) exact Bayesian inference without ever initializing or training a network and 2) closed form solution of network function under gradient descent training. We will discuss recent advances, applications and remaining challenges of the infinite-width limit of neural networks.

2021-03-18 / 16:15 ~ 17:15

학과 세미나/콜로퀴엄 - 콜로퀴엄: A region with simply-connected-boundary is not necessarily simply-connected.

by 최경수(고등과학원)

It is a gentle introduction to the mean curvature flow and its application to knot theory for undergraduate students. J.W.Alexander discovered a knotted sphere embedded in 3-dimensional Euclidean space in 1924. This example has provoked curiosity to find simple conditions under which embedded spheres are unknotted. In this talk we will sketch theorems and conjectures in the mean curvature flow for the knot theory, in analogy to the Ricci flow for the smooth 4-dimensional Poincare conjecture.

2021-03-19 / 16:00 ~ 17:00

학과 세미나/콜로퀴엄 - 대수기하학: Introduction to infinity-categories I

by 조창연(QSMS, Seoul National University)

Infinity-category theory is a generalization of the ordinary category theory, where we extend the categorical perspective into the homotopical one. Putting differently, we study objects of interest and "mapping spaces" between them. This theory goes back to Boardman and Vogt, and more recently, Joyal, Lurie, and many others laid its foundation. Despite its relatively short history, it has found applications in many fields of mathematics. For example, number theory, mathematical physics, algebraic K-theory, and derived/spectral algebraic geometry: more concretely, p-adic Hodge theory, Geometric Langlands, the cobordism hypothesis, topological modular forms, deformation quantization, and topological quantum field theory, just to name a few. The purpose of this series of talks on infinity-categories is to make it accessible to those researchers who are interested in the topic. We’ll start from scratch and try to avoid (sometimes inevitable) technical details in developing the theory. That said, a bit of familiarity to the ordinary category theory is more or less necessary. Overall, this series has an eye toward derived/spectral algebraic geometry, but few experience in algebraic geometry would hardly matter. Therefore, everyone is welcome to join us. This is the first in the series. We’ll catch a glimpse of infinity-category theory through some motivational examples.

Events for the 취소된 행사 포함