이재용 교수
Jaeyong Lee
서울대학교 통계학과 · 컴퓨터과학
연구실 소개
이재용 교수의 연구실은 베이지안 비모수통계 및 고도로 유연한 통계모델링을 핵심으로 하며, 특히 왜류(Left-truncation, Right-censoring) 데이터를 다루는 생존분석, 선택모형(Selection models)에서의 비모수적 가중함수 추정, 그리고 BART 기반의 순서형 데이터 분석 기법 개발에 주력하고 있습니다. 특히, 디리클레 과정, 중립성 기반 프로세스(NTR), MCMC 기반 추론 알고리즘 등 비모수적 사전분포의 이론적 기반과 실용적 적용을 결합한 연구가 두드러집니다. 연구는 의료, 환경, 약물 개발 등 다양한 분야의 복잡한 데이터를 효과적으로 분석할 수 있도록 기여하고 있습니다.
연구 현황
연구 성과 추이
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
주요 논문
15This paper is concerned with Bayesian analysis of the proportional hazard model with left truncated and right censored data. We use a process neutral to the right as the prior of the baseline survival function and a finite-dimensional prior is placed on the regression coefficient. We then obtain the exact form of the joint posterior distribution of the regression coefficient and the baseline cumulative hazard function. As a by-product, we prove the propriety of the posterior distribution with th
Selection models are appropriate when a datum x enters the sample only with probability or weight w(x). It is typically assumed that the weight function w is monotone, but the precise functional form of the weight function is often unknown. In this article, the Dirichlet process prior, centered on a parametric form, is used as a prior distribution on the weight function. This allows for incorporation of knowledge about the weight function, without restricting it to be of some particular function
Since Ferguson's seminal article on the Dirichlet process, the area of Bayesian nonparametric statistics has seen development of many flexible prior classes. At the center of the development lies the neutral to the right (NTR) process proposed by Doksum. Although the class of NTR processes is very rich in its members and has well-developed theoretical properties, its application has been restricted to very small portions of the class—mainly the Dirichlet, gamma, and beta processes. We believe th
The highly enantioselective aza-Michael reaction of <i>tert</i>-butyl β-naphthylmethoxycarbamate to cyclic enones has been accomplished by using a new <i>cinchona</i> alkaloid derived C(9)-urea ammonium catalyst under phase-transfer catalysis conditions with up to 98% ee at 0 °C. The resulting aza-Michael adducts can be converted to versatile intermediates by selective deprotection and the cyclic 1,3-aminoalcohols by diastereoselective reduction with up to 32:1, which have been widely used as im
Bayesian additive regression trees (BART) is a nonparametric model that is known for its flexibility and strong statistical foundation. To address a robust and flexible approach to analyse ordinal data, we extend BART into an ordered probit regression framework (OPBART). Further, we propose a semiparametric setting for OPBART (semi‐OPBART) to model covariates of interest parametrically and confounding variables nonparametrically. We also provide Gibbs sampling procedures to implement the propose
Abstract Ozonesondes collect data relevant to ozone level at various altitudes. Modeling these data involves a combination of spatial and temporal modeling. The spatial component can be conveniently modeled as a four component mixture of normal distributions. The (relatively few) parameters of this mixture can then be modeled in a time‐dependent fashion, via a dynamic linear model. Computations are carried out via Markov chain Monte Carlo methods. Copyright © 2003 John Wiley & Sons, Ltd.
We review the class of species sampling models (SSM). In particular, we investigate the relation between the exchangeable partition probability function (EPPF) and the predictive probability function (PPF). It is straightforward to define a PPF from an EPPF, but the converse is not necessarily true. In this paper we introduce the notion of putative PPFs and show novel conditions for a putative PPF to define an EPPF. We show that all possible PPFs in a certain class have to define (unnormalized)
Real Time Strategy (RTS) Game has the same problem which has to be solved in decision making in the real world. These problems are on real-time performance, high complexity caused by the large state space and multi-agent, insufficient information and on-line learning. AI which has been applied to RTS Game is somewhat limited and has poor performance due to these problems. Recent research to apply AI to RTS Game has proposed Dynamic Scripting. This method is generating rule-based game script by u
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