Heelim Hong

Ph.D. Candidate, Graduate School of Artificial Intelligence
Ulsan National Institute of Science and Technology (UNIST)
Advisor: Prof. Myeongjae Jeon

My research is in machine learning systems. I design systems that adapt how compute and memory are allocated at runtime, so that AI workloads meet their performance goals at lower cost. My work so far has focused on LLM serving, and I am now extending it to compound AI systems, where many model and tool calls must be optimized end to end.

Publications

Xinyue Ma*, Heelim Hong*, Taegeon Um, Jongseop Lee, Seoyeong Choy, Woo-Yeon Lee, Myeongjae Jeon
VLDB '26PVLDB, Vol. 19, No. 5* equal contribution
Summary

In long-context serving, the KV cache grows with every generated token and the batch keeps changing, so offloading plans fixed ahead of time cannot keep up with GPU memory demand. ORBITFLOW re-plans KV cache placement per request and per layer with a lightweight ILP solver and runtime feedback, raising SLO attainment for TPOT and TBT by up to 66% and 48% and throughput by up to 3.3× over existing offloading methods.

Taeyoon Kim, ChanHo Park, Mansur Mukimbekov, Heelim Hong, Minseok Kim, Ze Jin, Changdae Kim, Ji-Yong Shin, Myeongjae Jeon
VLDB '24PVLDB, Vol. 17, No. 4
Summary

Modern data augmentation is expensive enough that CPU-side preprocessing, not the GPU, becomes the training bottleneck. FusionFlow offloads part of each batch's augmentation onto idle GPU cycles without disturbing training, speeding up single-machine training by 16–285% over CPU-only preprocessing with 50–60% fewer CPUs than scaling out.

Education

  • 2021.09 –UNIST, Ulsan, KoreaCombined M.S./Ph.D., Graduate School of Artificial Intelligence
  • 2015 – 2021Chung-Ang University, Seoul, KoreaB.S., Department of Integrative Engineering

Awards

  • 2015 – 2021Da Vinci Scholarship VFull tuition for all semesters, awarded for admission with highest distinction
  • 2020 FallAcademic Excellence Scholarship

Teaching

  • 2024 SpringTA, AI Toolkits
  • 2022 FallTA, Optimizations for AI Systems
  • 2021 FallTA, Computer Architecture