My research has been driven by two primary keywords: HPC and Scalable, Secure AI.

Jiheon Choi (최지헌) received a B.S. degree in Software and Computer Engineering from Ajou University in Suwon, South Korea in August 2023. Currently, I am a Ph.D. student in the Department of Artificial Intelligence at Ajou University. I am a software engineer with over six years of experience in both academic research and industry applications. I am a member of the Distributed and Parallel Computing Lab, led by Ph.D. Sangyoon Oh. My research interests include high-performance computing, distributed AI/ML systems, and application security. You can contact me via email at unidev [at] ajou.ac.kr.

• High-Performance & Distributed Computing: HPC System Optimization and Job Scheduling
• AI & Machine Learning: Distributed ML Architecture (i.e., Distributed LLM and GNN), Federated Learning and Privacy-Preserving ML Techniques, Machine Learning for Resource Optimization
• Security & Privacy: Privacy-enhancing Techniques (i.e., Differential Privacy and Homomorphic Encryption), Automatic Security Vulnerability Assessment, Secure ML Systems Design

News

Education

• Ph.D. degree in Department of Artificial Intelligence at Ajou University. Advised by Ph.D. Sangyoon Oh.  Sep. 2023 - now
• B.S. degree in Department of Software and Computer Engineering at Ajou University.  Mar. 2019 - Aug. 2023

Publications Google Scholar

C: conferences, J: journals, W: workshops, P: preprints

2026

• [C5] Jiheon Choi, Minjoong Jeong, Sangjae Seo, Sangyoon Oh. Under Review Anonymous Title. Topic: graph parallelism. HPC-related venue.
• [C4] Jiheon Choi, Hyeokjun Jeong, Chanhyeok Jo, Hyunsouk Cho, Sangyoon Oh. Under Review Anonymous Title. Topic: federated learning. Cloud-related venue.
• [J4] Seokhyun Yoon, Jaeyoon Cheong, Jiheon Choi, Minjoong Jeong, Sangyoon Oh. Under Review Anonymous Title. TBA.
• [C3] Jiheon Choi, Sangyoon Oh. S-CQR: Stratified Calibration for Runtime Prediction in HPC Backfill Scheduling. The 32nd International European Conference on Parallel and Distributed Computing [Euro-par '26]. NRF-listed Major CS Conference [BK21, KIISE].
• [C2] Jiheon Choi, Sangyoon Oh. Reducing Backfill Failures from Workload Drift with Lightweight Uncertainty Buffers in HPC Job Scheduling. The 26th IEEE/ACM International Symposium on Cluster, Cloud and Grid Computing [CCGrid '26]. NRF-listed Major CS Conference [BK21, KIISE].
• [J3] Jiheon Choi, Sangyoon Oh. UARP: Uncertainty-Aware Runtime Prediction for Preventing Scheduler Termination under Wallclock Constraints in HPC. Journal of Supercomputing. [pdf]

2025

• [J2] Jiheon Choi, Sangyoon Oh. Lightweight Multi-Layered De-Identification Architecture: Secure Client Selection in Federated Learning. Journal of Systems Architecture (IF 4.1, JCR Q1). [pdf]
• [C1] Jiheon Choi, Jaehyun Lee, Minsol Choo, Taeyoung Yoon, Oh-Kyoung Kwon, Sangyoon Oh. When HPC Scheduling Meets Active Learning: Maximizing the Performance with Minimal Data. HPCAsia 2025: High Performance Computing in Asia-Pacific Region. [pdf]

2024

• [J1] Miri Yu, Jiheon Choi, Jaehyun Lee, Sangyoon Oh. Staleness Aware Semi-asynchronous Federated Learning. Journal of Parallel and Distributed Computing (JPDC) (IF: 4.0, JCR Q1). [pdf]

Domestic Publications (in Korean)

• 권도현, 최지헌, 정혁준, 김영훈, 오상윤. 로그 구조 병합 트리의 복합 질의 처리를 위한 보조 인덱스 구조 및 수행 전략 분석, 한국통신학회 동계학술대회 2026
• 정혁준, 조찬혁, 최지헌, 오상윤. 자율주행 데이터를 위한 연합학습 기반 불확실성 샘플링 벤치마킹 연구, 한국통신학회 추계학술대회 2025
• 임동현, 최지헌, 정재윤, 추민솔, 송봉섭, 오상윤. 자율주행 안전성 평가를 위한 시나리오 라이브러리 및 테스트 자동화 연구, 한국자동차공학회 추계학술대회 2025
• 최지헌, 이은학, 이재현, 오상윤. 다계층 스토리지 시스템 설계 및 평가: RocksDB를 활용한 MongoDB 쓰기 처리 가속, 한국통신학회 하계종합학술대회 2025 · NRF 정보융합기술단 특별세션
• 최지헌, 오상윤. 대규모 언어 모델 RAG 시스템의 벡터 인덱싱 확장성, 한국통신학회 동계종합학술대회 2025 [link]
• 윤태영, 최지헌, 권오경, 오상윤. HPC 환경에서 데이터 불균형을 고려한 작업 응용 예측 기법, 한국정보과학회 2024 한국소프트웨어종합학술대회 [link]
• 이민서, 최지헌, 윤태영, 오상윤. 스트리밍 기반의 고성능 데이터 파일 병합 기법, 한국정보과학회 2024 한국컴퓨터종합학술대회 [link]
• Sergio P. Caetano, Miri Yu, Jiheon Choi, Sangyoon Oh. Dynamic Programming-Based Multilevel Graph Partitioning for Large-Scale Graph Data, 한국통신학회 동계학술대회 2024 [link]
• Hyunsuk Jung, Jiheon Choi, Jongwon Park, Sehee Baek, Sangyoon Oh. Conditional LSTM-VAE-based Data Augmentation for Disaster Classification Prediction, The 9th International Conference on Next Generation Computing (ICNGC 2023) [link]
• 정현석, 최지헌, 박종원, 백세희, 오상윤. 화재 감지 시스템을 위한 MLOps 시스템 구조, 한국차세대컴퓨팅학회 춘계학술대회 2023 [link]
• 최지헌, 유미리, 윤대건, 오상윤. 연합학습에서의 보안 취약점 분석, 한국통신학회 동계종합학술발표회 2023 [link]
• 최지헌, 송봉섭, 오상윤. 자율주행 데이터 관리를 위한 백엔드 아키텍처 연구, 한국통신학회 하계종합학술발표회 2023 [link]
• 정준영, 구도훈, 김종민, 김주원, 이주명, 이상현, 이강석, 최지헌. 브라우저 확장 프로그램을 활용한 웹 취약점 분석 방안, 한국정보보호학회 동계학술대회 2021
• 최지헌. P2P 네트워크 기반 악성코드 분석 생태계 구현 방법, 한국정보보호학회 동계학술대회 2019

Patents

• [P6] Task Scheduling Device, Task Scheduling method thereof and Computing System. South Korea 10-2025-0078984 (Applied)
• [P5] Method and Apparatus for Classifying Workload Using Artificial Intelligence Model. South Korea 10-2023-0029398 (Applied)
• [P4] Apparatus and Method for Hotspot Prevention Based on Bloom Filter in Distributed Database Management System. South Korea 10-2024-0162896 (Applied)
• [P3] System and Method for Detecting Dynamic Web Vulnerability of Data Normalization of HTTP Headers for Classification of HTTP Headers. South Korea 10-2024-0159333 (Applied)
• [P2] Method for Automatic Diagnosis Vulnerability of Web and Apparatus for Performing The Method. South Korea 10-2311119 (Registered)
• [P1] System and Method for Analyzing Malicious Code Based on Blockchain. South Korea 10-222804 (Registered)

Work and Research Experience

• Lead Software and Security Engineer, MONTHLY HACKING Inc., Seoul, Republic of Korea (Aug 2020 - Dec 2023)
  • Co-founded the company with a non-technical partner and jointly led operations, while personally directing the technical R&D division and providing essential technical expertise for all strategic business decisions.
  • Delivered high-impact security consulting to well-known domestic startups (approximately 60+), uncovering critical vulnerabilities through penetration testing and providing rapid incident response during security breaches (e.g., penetration testing, vulnerability assessment, and incident response).
  • Engineered a sophisticated REST API for an automated penetration testing SaaS platform that transformed manual security processes into scalable solutions, enabling protection of enterprise-level systems with startup-sized security teams.
• Researcher, WAPAS SYSTEMS Inc., Incheon, Republic of Korea (Oct 2019 - Aug 2020)
  • Developed new research initiatives on mobile operating system security architectures (Android and iOS), including innovative bypass methodologies that significantly improved application functionality and secured new project funding.
  • Implemented a web application for a Philippine water shop that included both customer-facing ordering platform and robust administrative backend, after skillfully obtaining precise business requirements through effective stakeholder communication and translating complex operational needs into technical solutions that streamlined their entire water delivery service.
• Other Experience
  • BSKB's Summer Patent Seminar, Birch, Stewart, Kolasch & Birch, LLP (Jun 2023): Completed comprehensive training on U.S. patent law, including patent prosecution and litigation strategies, recent legal developments, and case studies at this prestigious annual legal seminar.

Research Projects

• [KISTI · National Research Council of Science and Technology] A Study on Graph Parallel Processing Algorithm Based on GPU. June 2024 - now
• [Ministry of Science and ICT] Development of multi-tiered, multi-purpose autotuning framework for exa-scale supercomputers. Nov 2023 - now
• [Samsung Display Inc.] Development of High Efficiency HPC Job Scheduling Algorithm. Jan 2024 - Feb 2025
• [Korea Automotive Technology Institute] Development of Safety of the intended functionality from insufficiency of perception and decision making. Sep 2022 - now
• [IITP] AI Application Technology with MR-IoT Convergence to countermeasure Disasters. Jan 2023 - Dec 2023
• [Ajou University] User Engagement in Social/Mobile Platforms and Its Welfare Value. Jan 2022 - Oct 2022
• [Ministry of SMEs and Startups] Development of Web Application Vulnerability Assessment Software. Apr 2022 - Dec 2022

Services

• Teaching Assistant, Ajou University. Jan 2022 - now
  • Distributed and Parallel Computing: Fall 2025
  • Object-oriented Programming: Spring 2024, Spring 2025, Spring 2026
  • Web System Design: Fall 2023, Fall 2024
  • Artificial Intelligence Convergence Capstone Design: Fall 2022, Spring 2023
  • Data Analytics–Machine Learning: Spring 2022
• Mentor, Developer Bootcamp Mentoring
  • Team Sparta Inc. (Jul 2022 - May 2023): React, Node.js
  • Coach, Elice Inc. (Nov 2021 - Aug 2022): React, Node.js
• Mentor, Korea Open Source Software Association (Oct 2020 - now)
  • Provided mentoring for the Open Source Software Developer Competition hosted by the Ministry of Science and ICT.
• Instructor, Korea Information Technology Research Institute (Aug 2021 - Dec 2021)
  • Conducted lectures on essential hacking techniques, encompassing web, mobile, and system hacking domains. Furthermore, delivered a lecture on ethical hacking best practices to participants. The “Cyber Guardians” program is specifically designed for high school students who aspire to initiate their learning journey in the field of information security.

Last updated: May 2026