Work & Experience

Senior ML Engineer building LLM-powered agentic systems, post-training pipelines, and evaluation infrastructure at scale.

Skills & Focus

Modeling & Methods

SFT, DPO/RLAIF, LoRA, Reward Modeling, RAG, Prompt Engineering, Red-Teaming

Focus Areas

LLM Post-Training, Agentic AI, Evaluation, Alignment, Synthetic Data

Systems & Infra

Multi-Agent Orchestration, Tool-Use Pipelines, Sandboxed Code Execution, CI/CD for ML

Languages & ML Stack

Python, Swift, C++, TypeScript · PyTorch, vLLM, Ray, Weights & Biases

Work Experience

Senior Machine Learning Engineer

Apple Inc. • Siri Core Modeling

Sep 2024 - Present Current
  • Drove post-training iteration loops (SFT → DPO/RLAIF → reward modeling) end-to-end, coordinating data curation, training runs, and deployment gating for models serving 1B+ devices.
  • Designed and delivered synthetic data pipelines (scenario generation, preference pairs, reward signals) that raised alignment pass rates from ~60% to 92%+ on internal safety benchmarks.
  • Shipped a fault-tolerant Natural-Language-to-Python platform spanning 2,000+ user intents, architecting a multi-stage system of semantic clustering, tool generation, and sandboxed code synthesis.
  • Achieved ~95% tool-calling accuracy on held-out multi-step agentic workflows by developing a rigorous evaluation harness with zero-shot testing, adversarial perturbations, and argument fuzzing.
  • Architected a meta-prompting self-improvement engine that turns failure patterns into automated remediation, reducing manual diagnostics and resolution effort by ~85%.
  • Built a unified evaluation framework with dataset versioning and a metric registry to consolidate disparate data stacks, enabling reproducible, traceable comparisons across all models and agents.
  • Led red-teaming sprints and built automated adversarial probing for jailbreak, prompt-injection, and policy-violation detection across agentic workflows.
  • Mentored junior engineers on evaluation-driven development and contributed to cross-org alignment standards for LLM safety and quality.

Machine Learning Engineer II

Apple Inc. • AI/ML

Sep 2021 - Sep 2024
  • Improved tool retrieval and query-to-program quality (+10% recall, −30% hallucinations) through RAG, LoRA/SFT on large models, prompt optimization, and user-simulation evals — early contributions to Apple Intelligence.
  • Built synthetic data and evaluation pipelines for intent understanding, enabling rapid iteration on LLM-driven features across Siri and system-level intelligence.
  • Increased OS update success rate by +25% by developing time-series forecasting models to smooth peak server loads and reduce resource contention failures.
  • Co-inventor on three U.S. patents covering sensor-driven display power control and predictive energy management.

Machine Learning Engineer

Apple Inc. • CoreOS

Aug 2020 - Sep 2021
  • Built on-device ML models for intelligent charging and background scheduling using device-state signals under strict privacy constraints, improving battery-health outcomes without cloud data.
  • Enabled Apple ProRes video on iPhone 13 Pro/Max by optimizing background task scheduling within power and thermal budgets.

Game Software Engineer

Tencent Holdings Ltd. • Interactive Entertainment Group

Jun - Aug 2019
  • Unity editor tools and real-time inspectors; ~3x designer workflow speed-up; shipped to titles serving 2M+ DAU.

Software Engineer

J.P. Morgan • Corporate & Investment Bank

Jun - Aug 2018
  • Spring Boot/Node.js monitoring for millions of instruments; Oracle SQL optimized ~120s → ~3s; led a 6-person LSTM prototype for predictive monitoring.

Patents & Awards

Patents

  • U.S. Patent No. 12,141,012 — Energy saving for battery powered devices (2024)
  • U.S. Patent No. 12,436,593 B2 — Sensor-based display power control (2025)
  • U.S. Patent No. 12,436,594 B2 — Predictive display power control (2025)

Academic Honors

  • Dean's Honors List, The University of Hong Kong (2015-2019)
  • CLP "Powering a Sustainable Generation" Scholarship (2017)
  • Zhiyuan Scholarship (Soong Ching Ling Foundation) (2015)

Education

University of California, Berkeley

2019 - 2020

M.Eng. in Electrical Engineering & Computer Science

GPA: 3.96

The University of Hong Kong

2015 - 2019

B.Eng. in Computer Science (First Class Honors)

Princeton University

2017

Exchange Student in Computer Science

GPA: 4.0

The first principle is that you must not fool yourself —
and you are the easiest person to fool.
Richard Feynman