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Contact Information

Name Zijian Feng
Professional Title Staff Applied Scientist, TikTok Business Integrity
Email vincent.fung13@gmail.com
Website https://vincentfung13.github.io

Experience

  • 2023 - present

    Singapore

    Staff Applied Scientist, Business Integrity
    TikTok Pte. Ltd.
    I lead a team of 7 full-time scientists and engineers building the AI foundation for TikTok Business Integrity, with a focus on large-scale foundation model data, moderation intelligence, and agentic system evaluation.
    • Agentic ads moderation system. Built an agentic content moderation system from scratch, end to end: problem definition, data curation, agentic SFT, agentic RL and serving. Adaptive feature selection through tool calls improves recognition performance and adapts quickly to policy changes, at a throughput of more than 2 QPS per NVIDIA H20.
    • Large-scale synthetic data for foundation models. Built a fine-grained integrity knowledge graph of more than 300 entities and an online multimodal synthetic-data pipeline that grounds real-world videos to granular risk concepts and generates aligned QA, captions, spatial grounding and agentic moderation tasks. The pipeline generates more than 2B tokens a day and continuously improves our in-house foundation model.
    • Agentic system evaluation. Built large-scale evaluation infrastructure and benchmark datasets for internal risk-operation agents, with automatic multi-round conversations against a user simulator, sandboxed trajectory rollouts with more than 20 internal skills, and evaluation of long-horizon tasks and memory.
  • 2021 - 2023

    Singapore

    Staff Research Engineer
    Gaussian Robotics
    Built the technical foundation from scratch for machine learning model training, evaluation and deployment on low-compute robotics systems.
    • Large-scale multi-task learning. Ran a dozen deep-learning recognition tasks on 2-TOPS edge devices and set up MLOps for fast model iteration.
    • Model development toolkit. Infrastructure for self-supervised pretraining, supervised training, INT8 quantization (PTQ and QAT) and runtime conversion.
    • End-to-end testing system. A hardware-in-the-loop (HIL) testing framework with a web interface for pre-release checks.
    • Foundation model research. A semi-automatic annotation system based on the Segment Anything Model (SAM), with fine-tuning techniques for in-house data.
  • 2020 - 2021

    Singapore

    Senior Research Scientist, AI Lab
    TikTok Pte. Ltd.
    Research on novel view synthesis and large-scale visual search.
    • Novel view synthesis. Co-developed MINE, dense 3D reconstruction from a single image with NeRF and multiplane images, published at ICCV 2021.
    • Visual search for TikTok e-commerce. Built the visual search embedding model for large-scale product retrieval from TikTok videos and co-designed the search pipeline and re-ranking.
  • 2019 - 2020

    Singapore

    Senior Research Engineer
    ViSenze Pte. Ltd.
    Large-scale visual search for e-commerce.
    • ICCV 2019 DeepFashion2 clothes retrieval challenge. Built the retrieval model and re-ranking pipeline that won 1st place.
    • Image retrieval. Trained most of the company’s online retrieval models and built the team’s training codebase; moved all online models to efficient architectures (MobileNet, ShuffleNet) with no accuracy drop; developed multi-task embedding training for category relevance.
    • Large-scale distributed training. Combined data and model parallelism to train arc-softmax embeddings over millions of classes.
  • 2016 - 2019

    Guangzhou, China

    Lead Research Engineer
    Tuputech
    Led a team of 5 research engineers on large-scale pedestrian recognition (Re-ID) and tracking.
    • Person re-identification and tracking. Built a system for pedestrian recognition and tracking across multiple cameras, with a data-driven Re-ID development workflow.
    • Image classification. Built and maintained a TensorFlow training platform that let solution engineers train and evaluate classifiers in a few clicks.

Research Interests

  • LLM/VLM post-training, application and evaluation: synthetic data, agentic RL, evaluation of content-understanding LLMs/VLMs and agents
  • Computer vision and robotics: 3D computer vision (scene understanding, novel view synthesis, depth estimation), large-scale image retrieval, object recognition (detection and segmentation), multi-task learning, deep model compression and quantization
  • ML infra and tools: PyTorch, Triton

Education

  • 2013 - 2016

    Glasgow, UK

    B.Sc. (Honours)
    University of Glasgow
    Computing Science

Awards

  • 2019
    1st place, ICCV 2019 DeepFashion2 Clothes Retrieval Challenge
    ICCV 2019 DeepFashion2 Workshop

Academic Service

Conference reviewer: ECCV'22, ICRA'22, CVPR'23, ICCV'23
Journal reviewer: IJCV