This study investigated the impact of rainfall on the network performance and video transmission quality of smart CCTV systems deployed across 16 bridges over the Han River in Seoul. Using operational logs collected from September 22 to October 6, 2025 (n=254), a comparative analysis was performed between the wired (n=5) and wireless (n=11) network architectures. The results reveal that under rainfall conditions, wireless networks experienced critical performance degradation. Specifically, at a heavy rainfall intensity of 10 mm/h, the average latency (Ping) surged from 22.5 ms to 355.2 ms, while video frame rates (FPS) plummeted from 19.8 to 6.4. Notably, at a maximum rainfall intensity of 15 mm/h, the wireless network performance exhibited a 78.8% degradation compared with clear weather conditions, severely compromising real-time monitoring reliability. Conversely, the wired networks exhibited robustness, maintaining a Ping of approximately 20 ms and an FPS within the 19–20 range, regardless of weather conditions. A significant negative correlation (r = -0.81, p < 0.01) between Ping and FPS was identified, establishing increased network latency as the primary driver of video quality degradation. These findings provide a technical basis for implementing real-time operational thresholds at Ping 40 ms and FPS 15 as leading indicators to ensure surveillance reliability in a smart city infrastructure.

ABSTRACT
1. 서론
    1.1. 연구의 배경 및 목적
    1.2. 연구의 범위 및 방법
2. 이론적 배경
    2.1. 교량 스마트 감시체계와 통신망 구조
    2.2. 강우와 무선 통신 성능 변동
    2.3. 네트워크 지연과 영상 품질 지표
    2.4. 선행연구의 한계
3. 연구방법
    3.1. 연구 대상지 및 시스템 구성
    3.2. 데이터 수집 및 전처리
    3.3. 분석 시나리오 및 방법
4. 분석 결과 및 고찰
    4.1. 기상 조건별 네트워크 지연(Ping) 변화 분석
    4.2. 기상 조건별 영상 연속성(FPS) 변화 분석
    4.3. Ping-FPS 상관관계 및 영상 품질 저하 메커니즘
    4.4. 분석결과 고찰
5. 결론
    5.1. 연구요약
    5.2. 시사점 및 제언
    5.3. 연구의 한계 및 향후 과제
REFERENCES

• 구본형(서울시립대학교 도시과학대학원 방재공학과 대학원생) | Gu Bonhoung
• 함승희(서울시립대학교 도시과학대학원 방재공학과 교수) | Haam Sunnie Corresponding author