Jiha Kim · 김지하

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

Jiha Kim 김지하

Research topics연구 주제

Multi-link contention stops being tractable the moment one radio has to serve three bands.

라디오 하나가 세 대역을 감당하는 순간, 멀티링크 경쟁은 풀리지 않는 문제가 됩니다.

Under the EMLSR active-link constraint the queues couple across links, so single-link Bianchi analysis no longer transfers. I build Markov/fixed-point closures that stay analytically auditable — exact under saturated STR, an availability-based approximation under EMLSR with its validity range made explicit — and drive the contention window from observables the MAC already has: collision rate, blocked ratio, queue backlog, head-of-line excess.

EMLSR의 단일 활성 링크 제약 아래에서는 큐가 링크 간에 결합되어, 단일 링크 Bianchi 해석이 그대로 옮겨가지 않습니다. 분석 가능성을 유지하는 Markov/고정점 폐형을 세우고 — 포화 STR에서는 엄밀하게, EMLSR에서는 유효 범위를 명시한 가용성 기반 근사로 — MAC이 이미 관측하는 값(충돌률, 차단 비율, 큐 적체, HOL 초과)으로 경쟁 윈도우를 제어합니다.

Ultra-high reliability is a promise about the worst one percent, not about the average.

초고신뢰성은 평균이 아니라 최악의 1%에 대한 약속입니다.

So the tail belongs in the objective. I carry p99 and p99.9 deadline-violation rates as Lyapunov drift-plus-penalty duals, price cross-BSS congestion once per beacon, and weight federated aggregation by measured interference rather than a plain mean — because averaging dilutes exactly the access points that need the most help.

그래서 꼬리 분위를 목적함수에 넣습니다. p99·p99.9 지연 위반율을 Lyapunov drift-plus-penalty의 쌍대변수로 다루고, 비컨마다 BSS 간 혼잡 가격을 한 번 산출하며, 연합 집성은 단순 평균이 아니라 측정된 간섭에 비례해 가중합니다 — 평균은 정작 가장 도움이 필요한 AP의 갱신을 희석시키기 때문입니다.

Deployed video arrives compressed, dropped and late. Models are usually trained as if it did not.

실제 운용 환경의 영상은 압축되고, 유실되고, 늦게 도착합니다. 모델은 대개 그렇지 않은 것처럼 학습됩니다.

My doctoral work makes attention degradation-aware and explainable: simulate packet loss, jitter and compression on the input, then teach spatial and temporal attention to weight what actually survived. Applied to weakly-supervised anomaly detection — where anticipation and detection share one representation — and to action recognition under a real compute budget.

학위 연구는 어텐션을 열화 인지적이고 설명 가능하게 만드는 데 있습니다. 입력에 패킷 손실·지터·압축을 시뮬레이션한 뒤, 공간·시간 어텐션이 살아남은 정보에 가중치를 두도록 학습시킵니다. 예측과 탐지가 하나의 표현을 공유하는 약지도 이상 탐지, 그리고 실제 연산 예산 안에서의 행동 인식에 적용합니다.

The same channel state that tells a MAC how bad the link is can also tell you where a body is.

링크 상태를 MAC에 알려주는 바로 그 채널 정보가, 사람이 어디에 어떤 자세로 있는지도 알려줍니다.

On MM-Fi, reported gains largely reflect better localization — Procrustes-aligned errors sit close to a mean-posture reference. So I route CSI by physics: sanitized per-antenna phase carries location, an amplitude-led composite carries posture, and a motion-consistency loss recovers the posture dynamics that pure localization misses.

MM-Fi에서 보고되는 성능 향상의 상당 부분은 사실 위치 추정 개선입니다 — Procrustes 정렬 오차가 평균 자세 기준선에 가깝습니다. 그래서 CSI를 물리적으로 분기시킵니다. 정제된 안테나별 위상은 위치를, 진폭 중심 합성 표현은 자세를 담당하며, 움직임 일관성 손실이 위치 추정만으로는 놓치는 자세 동역학을 회복합니다.

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
6 GHz 5 GHz 2.4 GHz TIME ACTIVE LINK
One radio, three bands. The active link moves; every other link still contends. 라디오는 하나, 대역은 셋. 활성 링크는 옮겨 다니고, 나머지 링크는 그동안에도 경쟁합니다.
p99 p99.9 DEADLINE MARGIN VIOLATION
Both tail quantiles enter the objective as duals — averaging the reward would hide exactly this region. 두 꼬리 분위를 쌍대변수로 목적함수에 넣습니다 — 보상을 평균 내면 바로 이 구간이 가려집니다.
EARLY WARNING EVENT ONSET FRAMES · DASHED = DEGRADED BY THE LINK
Attention is trained on degraded input, and the anticipation branch scores the event before its annotated onset. 어텐션을 열화된 입력에서 학습시키고, 예측 분기가 주석된 사건 시작 이전에 점수를 올립니다.
CSI · PER-ANTENNA PHASE + AMPLITUDE PHYSICAL ROUTING DEVICE-FREE 3D POSE
Phase routes to location, an amplitude-led composite to posture — the split is set by measured recoverability. 위상은 위치로, 진폭 중심 합성 표현은 자세로 보냅니다 — 이 분기는 측정된 복원 가능성에 따라 정했습니다.
9 Published papers게재 논문
17 Domestic국내 발표
5 Under review투고 중
6 Patents filed특허 출원
60 Citations피인용 Google Scholar
5 h-index i10 · 1
01

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
02

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
03

Domestic국내 발표

17

Korean Institute of Communications and Information Sciences (KICS) conferences and JCCI. Titles are given as published, in Korean.

한국통신학회(KICS) 종합학술발표회 및 통신정보 합동학술대회(JCCI) 발표 논문입니다.

Domestic — first author국내 발표 — 제1저자

IW-FedMAPPO: 비대칭 OBSS Wi-Fi 8 네트워크에서 초고신뢰 조정 MLO 스케줄링을 위한 간섭 가중 연합 다중 에이전트 근접 정책 최적화

Interference-Weighted Federated Multi-Agent PPO for Ultra-Reliable Coordinated MLO Scheduling

SEAR: 공유적 증거 이상 및 위험 탐지 — 비디오 탐지 및 다중 시간 지평 예측 통합 프레임워크

Shared Evidential Anomaly and Risk Detection

QA-FedDQN: 독립 배치 다중 AP Wi-Fi 네트워크를 위한 품질 인식 적응적 연합 심층 Q-Network

Quality-Aware Adaptive Federated Deep Q-Network for Distributed Multi-AP Wi-Fi

PRIME Wi-Fi: Wi-Fi의 멀티링크 효율성을 위한 예측적 리소스 인텔리전스

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

동적 컨볼루션과 다중 스케일 시공간 주의 메커니즘을 사용한 비디오 분류 모델

Video classification with dynamic convolution and multi-scale spatio-temporal attention

자율주행을 위한 Unknown Object Detection 연구 동향: Multi-Modal 접근과 불확실성 인식 기법

Research trends in unknown object detection for autonomous driving

수직 및 수평 필터를 활용한 이중 생성자 구조를 통한 GAN의 이미지 생성 품질 향상

Improving GAN image quality with a dual-generator structure

5G mMTC 환경에서 2-pair UE NOMA를 이용한 sectorization 랜덤 액세스 절차의 성능 비교

Sectorized random access with 2-pair UE NOMA in 5G mMTC

다중 클래스 데이터 셋에서의 딥 러닝 성능 개선을 위한 다중 출력 모델 제안

A multi-output model for deep learning on multi-class datasets

Multi-Link Operation의 Internal Interference를 위한 적응적 Contention Window 기법

Adaptive contention window for internal interference in multi-link operation

GAN Data augmentation을 위한 검증 및 설명 가능한 VX-GAN 모델

VX-GAN: a validation and explainable GAN model for data augmentation

CNN 알고리즘을 이용한 소형 임베디드 인물 판별 시스템 모델

Face recognition model for small embedded systems based on CNN

Domestic — co-author국내 발표 — 공저

UAV를 활용한 통합 시맨틱 객체 인식 기반 도로 밀집도 이상 영역 탐지

Road-density anomaly detection from UAV semantic object recognition

SDN 환경에서 서비스별 네트워크 요구사항에 따른 우선순위 결정 기법

Service-aware prioritization by network requirement in SDN

사용자별 가중치 표준 편차를 활용한 Federated Learning 성능 향상 기법

FedSD: federated learning using per-user weight standard deviation

NHANES 데이터를 이용한 생활 패턴 기반의 우울증 예측 머신러닝 기법

Lifestyle-based depression prediction from NHANES data

MEC 환경에서 5G-V2X 기반 사고 예방 시스템 제안

A 5G-V2X accident-prevention system in MEC environments

04

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

05

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.

06

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