Yikun Zhang (he/him)

Doubly Robust Inference on Causal Derivative Effects for Continuous Treatments
Yikun Zhang, Yen-Chi Chen
Statistical methods for causal inference with continuous treatments mainly focus on estimating the mean potential outcome function, commonly known as the dose…

Efficient Inference on High-Dimensional Linear Models with Missing Outcomes
Yikun Zhang, Alexander Giessing, Yen-Chi Chen
This paper is concerned with inference on the regression function of a high-dimensional linear model when outcomes are missing at random. We propose an…

Nonparametric Inference on Dose-Response Curves Without the Positivity Condition
Yikun Zhang, Yen-Chi Chen, Alexander Giessing
Existing statistical methods in causal inference often assume the positivity condition, where every individual has some chance of receiving any treatment level…

SCONCE: A cosmic web finder for spherical and conic geometries
Yikun Zhang, Rafael S. de Souza, Yen-Chi Chen
The latticework structure known as the cosmic web provides a valuable insight into the assembly history of large-scale structures. Despite the variety of…

Linear Convergence of the Subspace Constrained Mean Shift Algorithm: From Euclidean to Directional Data
Yikun Zhang, Yen-Chi Chen
This paper studies the linear convergence of the subspace constrained mean shift (SCMS) algorithm, a well-known algorithm for identifying a density ridge…

Mode and Ridge Estimation in Euclidean and Directional Product Spaces: A Mean Shift Approach
Yikun Zhang, Yen-Chi Chen
The set of local modes and the ridge lines estimated from a dataset are important summary characteristics of the data-generating distribution. In this work, we…

Kernel Smoothing, Mean Shift, and Their Learning Theory with Directional Data
Yikun Zhang, Yen-Chi Chen
Directional data consist of observations distributed on a (hyper)sphere, and appear in many applied fields, such as astronomy, ecology, and environmental…

The EM Perspective of Directional Mean Shift Algorithm
Yikun Zhang, Yen-Chi Chen
The directional mean shift (DMS) algorithm is a nonparametric method for pursuing local modes of densities defined by kernel density estimators on the unit…