Zeke Zhang

Computer Science & Mathematics
University of Wisconsin–Madison

I build trading-system prototypes, machine learning systems, and quantitative research tools, with an emphasis on reproducible evaluation, clear system boundaries, and measured results.

Most of my work follows the same shape: take a method that is supposed to help, build the harness that can actually tell whether it did, and report the number that comes back — including when it is smaller than expected. The projects below are written that way, and state the limits of what their measurements support.

Selected work

Limit Order Book Matching Engine

Reviewed version Passing CI

A single-instrument, price–time priority matching core built around a flat price ladder, two-level bitmap, pooled intrusive FIFO queues, and an open-addressing order-ID map. A separate std::map reference supports differential testing across 1.6 million messages; regression tests cover reserved IDs, invalid configurations, and order lifecycle edge cases.

Apple M4 · single thread · 5M synthetic messages · median of 7 runs
Flat ladder engine91.3 Mmessages/s
Map reference16.1 Mmessages/s

In-process synthetic replay excludes parsing and network I/O. This measures the matching core, not production exchange throughput or end-to-end latency. The LOBSTER adapter has synthetic-fixture coverage, not validation against a real exchange dataset.

  • C++20
  • Cache-aware data structures
  • Differential testing
  • ASan / UBSan

A-Share Factor Research Pipeline

Research report Passing CI

A reproducible ten-factor study of the CSI 300 point-in-time universe, covering 2018–2025 H1. Factor selection uses 2018–2021 only; 2022–2025 H1 is held out. The pipeline includes size neutralization, next-open execution, drift-adjusted turnover, and a survivorship-bias comparison. Locked dependencies, SHA-256 data manifests, and a frozen 100-stock sample make the evaluation testable in CI.

Composite factor · out-of-sample 2022–2025 H1 · 5-day horizon
Mean RankIC0.0324Spearman
Annualized ICIR1.44annualized
Q5 − Q1 annualized return14.0% / 5.2%gross / net

Historical A-share research, not a demonstrated live strategy. The long–short spread is hypothetical: shorting restrictions, borrow costs, and market impact are not modeled. Results are not evidence of transferability to U.S. equities. The linked report includes the reviewed turnover correction.

  • Python
  • pandas / NumPy
  • Point-in-time universe
  • Regression testing

MiniMind Systems

Systems extensions on top of MiniMind: a preallocated static KV cache, request batching, and an observable FastAPI serving path with Prometheus metrics. Equivalence tests pin the cache to the reference implementation; the benchmark harness emits JSON reports rather than screenshots.

Exploratory runs · Apple Silicon CPU · 532,864-parameter model
Static cache vs. no cache +74.10% tokens/s
Static cache vs. existing dynamic cache +0.11% tokens/s
Batched serving batch 8 vs. batch 1 +155.20% requests/s

Short local runs on a CPU micro-model — not GPU results, statistical guarantees, or model-quality claims. The +0.11% row is reported precisely because it is not evidence of a robust speedup.

  • PyTorch
  • FastAPI
  • Static KV cache
  • Dynamic batching
  • Prometheus

Explainable ESG Risk & Reporting

Live demo three precomputed companies — Pages cannot run the model

A leakage-aware modeling benchmark, a SHAP evidence bundle, and a FastAPI service that returns a risk estimate alongside the strongest positive and negative contributions behind it. Encoding, imputation, and scaling are fitted inside each training fold, so the comparison below is not flattered by the validation split.

430 eligible companies · 5 shared folds · seed 42 · lower is better
ModelOOF RMSEOOF MAE
Training-fold mean (baseline)6.8905.615
CatBoost4.8703.728
ElasticNet5.9134.812
LightGBM6.0034.709
Equal-weight blend5.3314.232

Internal cross-validation estimates on a historical cross-sectional dataset — not future-period or external validation. The blend did not beat CatBoost in this run.

Grand Prize 2025 Zhixiang Cup — national university economics and management case competition. The award applies to the original competition case; the repository documents the later engineering release.

  • CatBoost
  • SHAP
  • scikit-learn
  • FastAPI

Interests

Machine learning systems · applied mathematics · interpretable modeling · quantitative research.

Currently reading into inference-time efficiency and evaluation design — the question of what a benchmark is actually licensed to conclude.

Contact

Open to research collaborations and internships. Email is the fastest way to reach me: zhengji.zhang@wisc.edu. Code and ongoing work live on GitHub.