Current focus
Self-evolvable software I am a PhD student in Computer and Information Science at the University of Pennsylvania, advised by Ryan Marcus. My work sits at the intersection of database systems, machine learning, and machine programming. I am interested in software that can observe its own behavior, adapt at runtime, and evolve without losing the guarantees that make systems dependable.
Advised by Ryan Marcus ↗ (opens in a new window) at the Penn Database Group ↗ (opens in a new window) .
R.01
Adaptive execution How can a database choose better physical behavior at microsecond timescales?
I study execution engines that learn from fine-grained runtime feedback and change strategy as data and workloads shift.
Piece of CAKE ↓ R.02
Workload understanding What do production traces hide about the work users actually wanted to run?
I examine the feedback loop between platforms and users so workload data can be interpreted without mistaking survivors for demand.
Survivorship Bias ↓ R.03
Self-evolvable software Can software adapt inputs, policies, and implementations instead of waiting for retraining or manual tuning?
My broader goal is to combine machine learning with program structure to build systems that improve while they run.
CodeImprove ↓ Ref. / date Title / authors / contribution Venue Access
P—01 2026.02
Piece of CAKE: Adaptive Execution Engines via Microsecond-Scale Learning Zijie Zhao, Ryan Marcus
A microsecond-scale learning system selects a physical kernel for each data morsel, reducing end-to-end workload latency by up to 2×.
DATABASE SYSTEM QUERY PROCESSING MACHINE LEARNING Venue: UNDER REVIEW
P—02 2025.10
Survivorship Bias in Industrial Database Workloads Ryan Marcus, Jeffrey Tao, Peizhi Wu, Zijie Zhao · All authors contributed equally.
Shows how production traces encode a negotiation between users and platforms—and why the queries missing from those traces matter.
DATABASE SYSTEM QUERY OPTIMIZATION SURVIVORSHIP BIAS Venue: CIDR 2026 Best Paper
P—03 2025.05
CodeImprove: Program Adaptation for Deep Code Models Ravishka Rathnasuriya, Zijie Zhao, Wei Yang
Adapts out-of-scope programs with semantics-preserving transformations, improving deep code models without frequent retraining.
SOFTWARE ENGINEERING DEEP LEARNING PROGRAM ANALYSIS Venue: ICSE 2025
P—04 2025.04
NuClass: An ontology-driven vision–language foundation model for zero-shot nuclei classification Yinuo Xu, Jina Kim, Zijie Zhao, Zhi Huang
An ontology-aware vision–language foundation model for zero-shot nuclei classification across tissues and unseen cell classes.
MEDICAL IMAGE VISION-LANGUAGE MODEL DEEP LEARNING Venue: MMFM-BIOMED @ CVPR 2025
Access: Not public
2024—present PhD, Computer and Information Science University of Pennsylvania Advised by Ryan Marcus · Penn Database Group
Completed 2026
MA, Statistics The Wharton School Completed 2024
BE, Computer Science Tianjin University