Jiha Kim · 김지하

Myongji University · DAN Lab · Integrated MS–PhD 명지대학교 · DAN 연구실 · 석·박사 통합과정

Jiha Kim 김지하

I design medium access control for the next generation of Wi-Fi, and attention models that keep working when the network underneath them does not. Both halves of that sentence are the same problem: deciding what to spend scarce capacity on, and when.

차세대 Wi-Fi의 매체 접근 제어(MAC)를 설계하고, 그 네트워크가 흔들릴 때도 견디는 어텐션 모델을 연구합니다. 두 주제는 결국 하나의 문제입니다 — 한정된 자원을 무엇에, 언제 쓸 것인가.

My current work centres on IEEE 802.11bn (Wi-Fi 8) ultra-high reliability: Markov/fixed-point analysis of EMLSR multi-link contention, and constrained multi-agent reinforcement learning that holds p99 deadline guarantees across dense overlapping BSSs. In parallel I build video models — anomaly anticipation, action recognition, WiFi-CSI pose estimation — under the degradation real links actually produce.

현재는 IEEE 802.11bn(Wi-Fi 8) 초고신뢰성(UHR)에 집중하고 있습니다. EMLSR 멀티링크 경쟁의 Markov/고정점 해석, 그리고 밀집 OBSS 환경에서 p99 지연 보장을 유지하는 제약 기반 다중 에이전트 강화학습이 중심입니다. 동시에 이상 예측, 행동 인식, WiFi-CSI 자세 추정 등 실제 링크 열화를 견디는 비디오 모델을 만듭니다.

Position 과정 Integrated MS–PhD Candidate, 2020–present 석·박사 통합과정, 2020–현재
Dept. 학과 Information & Communication Engineering 정보통신공학과
Lab 연구실 DAN Lab — Distributed AI and Networked Robotics — 분산 AI 및 네트워크 로보틱스
Advisor 지도교수 Prof. Hyunhee Park 박현희 교수
Elsewhere 링크 Google Scholar · GitHub · Blog
EMLSR multi-link operation — the object of study EMLSR 멀티링크 동작 — 연구 대상

one radio, three bands, contention on every link 라디오 1개 · 대역 3개 · 링크마다 경쟁

6 GHz 5 GHz 2.4 GHz TIME
9 Published papers게재 논문
5 Under review투고 중
6 Patents filed특허 출원
60 Citations피인용 Google Scholar
5 h-index i10 · 1
3 Funded projects참여 과제

Research연구 분야

01

Reliability-oriented MAC for Wi-Fi 8 Wi-Fi 8 신뢰성 중심 MAC

Multi-link contention resists closed-form analysis once the EMLSR single-active-radio constraint couples queues across bands. I build Markov/fixed-point closures that stay analytically auditable, then drive contention windows from MAC observables inside the standard EDCA loop.

EMLSR의 단일 활성 라디오 제약이 대역 간 큐를 결합시키면 멀티링크 경쟁은 닫힌 형태로 풀리지 않습니다. 분석 가능성을 유지하는 Markov/고정점 폐형을 세우고, 표준 EDCA 루프 안에서 MAC 관측값으로 경쟁 윈도우를 제어합니다.

802.11bnMLO / EMLSRMarkov
02

Constrained RL for network control 제약 기반 강화학습 네트워크 제어

Ultra-high reliability is a tail problem, not a mean problem. I use Lyapunov drift-plus-penalty to put p99 and p99.9 violation rates directly into the learning signal, with federated aggregation weighted by measured interference rather than plain averaging.

초고신뢰성은 평균이 아니라 꼬리 분위의 문제입니다. Lyapunov drift-plus-penalty로 p99·p99.9 위반율을 학습 신호에 직접 넣고, 단순 평균 대신 측정된 간섭에 비례한 가중치로 연합 집성을 수행합니다.

MARLLyapunovFederated
03

Video understanding under degradation 열화 환경에서의 비디오 이해

Packet loss, jitter and aggressive compression are the normal operating condition for deployed video, not an edge case. My doctoral work makes attention degradation-aware and explainable, spanning anomaly anticipation, action recognition and device-free CSI sensing.

패킷 손실, 지터, 강한 압축은 예외가 아니라 실제 운용 환경의 기본값입니다. 학위 연구는 어텐션을 열화 인지적이고 설명 가능하게 만드는 데 있으며, 이상 예측·행동 인식·비접촉 CSI 센싱을 포함합니다.

ViTWVADWiFi-CSI

Trajectory — where the work has gone 연구 궤적 — 주제의 이동

Blockchain & distributed ledgers 블록체인 · 분산 원장 IMIS
11편
Explainable AI & GAN 설명 가능한 AI · GAN ICUFN · IMIS · ICT Express
4 papers4편
Reinforcement learning for wireless resource control 무선 자원 제어를 위한 강화학습 ICTC · IEEE Access
2 papers2편
Wi-Fi multi-link & ultra-high reliability Wi-Fi 멀티링크 · 초고신뢰성 BWCCA · KICS · IEEE TMC
6 papers6편
Video understanding & wireless sensing 비디오 이해 · 무선 센싱 IMIS · JCCI · under review
5 papers5편

Publications논문

09 + 05
Output by year연도별 실적 one mark = one paper · 2020–2026 마크 1개 = 논문 1편 · 2020–2026
IMIS 2020 — Accounting ledger system on Hyperledger Fabric ICUFN 2021 — OA-GAN IMIS 2021 — Reduced CNN Model for Face Image Detection IMIS 2022 — Hierarchical output model of CNN learning ICT Express 2023 — Limited Discriminator GAN ICTC 2023 — RL-Based Backoff Indicator for 5G NR IEEE Access 2024 — Dynamic Transmission and Delay Optimization BWCCA 2024 — Multi-Link/Multi-AP Coordination for Seamless Roaming IMIS 2025 — STCA-Net KICS Summer 2025 — PRIME Wi-Fi KICS Winter 2026 — Adaptive Federated DRL for Multi-AP Wi-Fi JCCI 2026 — SEAR KICS Summer 2026 — IW-FedMAPPO Under review — IEEE TMC, EMLSR contention control Under review — LyMAPPO Under review — STCA-ViT Under review — PhysRoute-Fi Under review — SEAR 2020 2021 2022 2023 2024 2025 2026
  • Journal학술지
  • International conf.국제학회
  • Domestic conf.국내학회
  • Under review투고 중

Journal Articles학술지 논문

Dynamic Transmission and Delay Optimization Random Access for Reduced Power Consumption

IEEE Access, vol. 12, pp. 55033–55050, April 2024

Limited Discriminator GAN using explainable AI model for overfitting problem

ICT Express, vol. 9, no. 2, pp. 241–246, 2023

International Conferences국제 학술대회

STCA-Net: Spatio-Temporal Convolutional Attention Network for Efficient Action Recognition in Videos

International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS), 2025

Multi-Link/Multi-AP Coordination Based Joint Transmission for Seamless Roaming in IEEE 802.11bn (Wi-Fi 8)

International Conference on Broadband and Wireless Computing, Communication and Applications (BWCCA), 2024

Optimization of Reinforcement Learning-Based Backoff Indicator for 5G NR Random Access Procedure

International Conference on ICT Convergence (ICTC), 2023

Hierarchical output model of CNN learning using multi-label datasets

International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS), 2022

OA-GAN: Overfitting Avoidance Method of GAN Oversampling based on Explainable AI

International Conference on Ubiquitous and Future Networks (ICUFN), July 2021

Reduced CNN Model for Face Image Detection with GAN Oversampling

International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS), 2021

An Accounting Ledger System using the Hyperledger Fabric-based Blockchain

International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS), 2020

Under Review투고 중

Reliability-Aware Adaptive Contention Control for EMLSR Multi-Link Operation in IEEE 802.11bn WLANs

IEEE Transactions on Mobile Computing — under review — 심사 중

Abstract초록

IEEE 802.11bn Ultra High Reliability (UHR) extends multi-link operation toward a reliability-oriented MAC, but multi-link contention under the EMLSR active-link constraint resists closed-form analysis. We develop a Markov/fixed-point closure for three-band MLDs coexisting with single-link legacy stations: exact under saturated, per-link-independent STR; reducing to an availability-based approximation under saturated EMLSR with an explicit validity range; and extending to unsaturated traffic through per-link Bernoulli arrivals. On top of it we build a controller that adapts the per-link minimum contention window from MAC observables inside the standard EDCA/EMLSR loop. Against SLD, STR-MLD and static-EMLSR baselines it raises throughput by 10.6%, lowers 95th-percentile HOL-service delay by 28%, and improves Jain's fairness from 0.910 to 0.954 at 48 stations. Triangulation across the analytical model, a discrete-event simulator and ns-3 closes within a 2–4% mean relative gap.

+10.6% throughput −28% p95 HOL delay fairness 0.910 → 0.954 model ↔ ns-3 gap 2–4%

LyMAPPO: Lyapunov-Constrained Independent Learning for Ultra-High Reliability in Dense Multi-Band Wi-Fi

Under review심사 중

Abstract초록

IEEE 802.11bn defines ultra-high reliability through per-BSS deadline-violation-rate targets. We study these constraints in dense multi-band deployments with heterogeneous AP link sets. LyMAPPO combines independent per-AP PPO with drop-inclusive rate-form Lyapunov duals, one dual-derived congestion price per beacon for cross-BSS coordination, and an auxiliary lower-tail quantile critic. Training and evaluation use an ns-3-in-the-loop environment with 16 APs, three bands, shared-buffer multi-link operation and Markov channels. Across 16 seeds with 110 s episodes, LyMAPPO achieves 15.1/16 feasible BSSs and a network p99 of 0.0017 — 6.1× to 25× lower than three static baselines. The drift-plus-penalty analysis accounts for clipping and establishes a run-time dual-stability condition under the Slater assumption.

network p99 0.0017 6.1–25× lower than static 15.1/16 feasible BSS 16 APs · 3 bands · ns-3

STCA-ViT: Spatio-Temporal Cross-Attention Vision Transformer for Video Action Recognition

Under review심사 중

Abstract초록

STCA-ViT is a hybrid framework integrating a VideoMAE ViT-Base backbone with bidirectional spatio-temporal cross-attention, Sobel-based boundary detection for motion gating, and YOLO-based person attention in parallel. It adds residual contribution fusion with gradient reversal for feature diversity, orthogonal regularization, a multi-head ensemble classifier, and an optional weakly-supervised temporal action localization head that recycles motion features into frame-level scores without temporal annotations. STCA-ViT reaches 90.46% Top-1 on HMDB-51 — above VideoMAE V2 ViT-g (86.08%) — with 98.29% on UCF-101, 79.44% on Kinetics-400 and 65.01% on Something-Something-v2, using 110M parameters and 305 GFLOPs.

HMDB-51 90.46% UCF-101 98.29% K-400 79.44% 110M params · 305 GFLOPs Code ↗코드 ↗

PhysRoute-Fi: Physically-Routed Two-Branch WiFi-CSI 3D Human Pose Estimation

Under review심사 중

Abstract초록

WiFi channel state information supports device-free 3D pose estimation, but posture and motion remain hard to recover across subjects and scenes. On MM-Fi, recent estimators' Procrustes-aligned errors (99.8–106.2 mm) sit close to a mean-posture reference (99.4–103.6 mm), indicating much of the reported gain comes from localization. PhysRoute-Fi separates CSI into physical components and assigns them to pose factors: sanitized per-antenna phase is fused with an amplitude-led composite representation for location, while the composite representation drives a graph-convolutional posture decoder. With one-time enrollment, a motion-consistency loss recovers about 93% of the aggregate inter-frame displacement magnitude and reaches 102.7 mm MPJPE and 65.5 mm PA-MPJPE.

MPJPE 102.7 mm PA-MPJPE 65.5 mm 93% motion recovered

SEAR: Segment-level Early Anomaly Recognition via Cross-Task Anticipation Gating and Temporal Contrastive MIL

Under review심사 중

Abstract초록

Weakly-supervised video anomaly detection localizes frame-level anomalies using only video-level binary labels. Existing methods treat anomaly detection and risk anticipation as independent tasks, discarding cross-task predictive cues. SEAR jointly performs multi-horizon risk anticipation and MIL-based detection through a shared representation via three contributions: a Cross-Task Anticipation Gate, a zero-initialized scalar that modulates detection features with anticipation risk scores; Temporal Contrastive MIL, a hinge-loss objective separating peak anomaly scores from all normal scores; and Curriculum Pseudo-Labeling with Negative Mining. On UCF-Crime, SEAR reaches 85.36% frame-level AUC with frozen dual encoders (~0.59M trainable parameters), and 87.78% AUC under triple-encoder fusion — the highest among frozen-encoder methods. It detects 89% of anomalous videos before annotated event onset.

UCF-Crime AUC 87.78% AP 33.04% 0.59M trainable params 89% detected pre-onset

Selected Domestic Conferences (KICS)국내 학술대회 (한국통신학회)

IW-FedMAPPO: Interference-Weighted Federated Multi-Agent PPO for Ultra-Reliable Coordinated MLO Scheduling in Asymmetric OBSS Wi-Fi 8 Networks

SEAR: Shared Evidential Anomaly and Risk Detection — Unified Framework for Video Detection and Multi-Horizon Anticipation

Adaptive Federated Deep Reinforcement Learning for Multi-AP Wi-Fi Optimization

PRIME Wi-Fi: Predictive Resource Intelligence for Multi-Link Efficiency in Wi-Fi

Patents특허

06

Korean patent applications filed through the Myongji University Industry–Academic Cooperation Foundation, with Prof. Hyunhee Park.

명지대학교 산학협력단을 통해 박현희 교수와 공동 출원한 국내 특허입니다.

2022 — GAN-based model learning 2023 — RL-based random access procedure 2024 — Non-AP MLD handover for joint transmission 2024 — UMAC-based AP MLD cooperative transmission 2024 — Non-AP MLD cooperative-transmission reception 2024 — Parameter exchange for multi-AP-MLD joint transmission 2022 2023 2024 ×4

A Method for Performing Handover of Non-AP MLD for Multiple AP MLDs Performing Joint Transmission, and a Device Therefor

Ref. PD241137 · filed 23 Dec 20242024.12.23 출원

A Method for Performing Cooperative Transmission of UMAC-based AP MLD in Wireless LAN Network and an Apparatus Therefor

Ref. PD241138 · filed 23 Dec 20242024.12.23 출원

A Method for Receiving Cooperative Transmission Data of Non-AP MLD in Wireless LAN Network and an Apparatus Therefor

Ref. PD241139 · filed 23 Dec 20242024.12.23 출원

A Method for Parameter Exchange for Joint Transmission Among Multiple AP-MLDs Supporting Multi-Link, and Device Therefor

Ref. PD241140 · filed 23 Dec 20242024.12.23 출원

Method for Performing Random Access Procedure Based on Reinforcement Learning

10-2023-0196634 · published KR 10-2025-0104336 A, 8 Jul 2025공개 KR 10-2025-0104336 A, 2025.07.08

Method and Apparatus for GAN-based Model Learning

10-2022-0024885 · published KR 10-2023-0127508 A, 1 Sep 2023공개 KR 10-2023-0127508 A, 2023.09.01

Projects연구 과제

NRF 2022R1A2C2005705AI-MAC for flying base stations
MOTIE / KEIT RS-2024-00469138Vision SDK on domestic AI semiconductors
Innopia TechnologiesVideo clip understanding

Vision Recognition Technology SDK Based on Domestic AI Semiconductors 국산 AI 반도체 기반 비전 인식 기술 SDK 개발

RS-2024-00469138

Vision models targeted at domestic AI accelerators — the constraint that pushed my action-recognition work toward accuracy-per-GFLOP rather than accuracy alone.

국산 AI 가속기를 대상으로 하는 비전 모델 개발. 정확도만이 아니라 GFLOP당 정확도를 기준으로 행동 인식 연구를 설계하게 된 배경입니다.

AI-MAC Protocol for Intelligent Flying Base Stations Based on Distributed Machine Learning 분산 기계학습 기반 지능형 비행 기지국을 위한 AI-MAC 프로토콜

2022R1A2C2005705

Distributed learning for MAC-layer decisions in UAV-assisted networks; the origin of my multi-UAV energy and Age-of-Information work.

UAV 기반 네트워크의 MAC 계층 의사결정을 위한 분산 학습 연구. 다중 UAV 에너지·AoI 최적화 연구의 출발점입니다.

Video Clip Understanding for Media Recommendation 미디어 추천을 위한 비디오 클립 이해

Innopia Technologies (이노피아테크)

Person-centred clip analysis over a broadcast video corpus: CLIP-based embeddings, scene and appearance analysis, and retrieval built on top of them.

방송 영상 코퍼스를 대상으로 한 인물 중심 클립 분석. CLIP 기반 임베딩, 장면·출연 분석 및 이를 활용한 검색 파이프라인을 구축했습니다.

Education학력

Integrated Master's–PhD Program 석·박사 통합과정

Myongji University · Department of Information and Communication Engineering 명지대학교 정보통신공학과

Doctoral thesis: Attention-Based Robust Learning Method for Explainable Video Understanding under Communication Constraints — advised by Prof. Hyunhee Park.

학위논문: 통신 환경을 고려한 설명 가능한 비디오 이해를 위한 Attention 기반 강건 학습 기법에 관한 연구 — 지도교수 박현희.

B.S., Computer Software Engineering 컴퓨터소프트웨어학과 학사

Korea Bible University 한국성서대학교