Earthquakes can damage transmission system components, leading to extensive blackouts and disrupting essential societal functions. In urban areas, interruptions in power supply critically impact sectors such as industry, healthcare, and telecommunications, highlighting the need for quantitative and systematic analysis. Most existing research has focused on assessing seismic fragility at the individual facility level, with insufficient probabilistic safety evaluations that consider the connectivity of entire transmission systems. This study aims to quantify the connectivity-based seismic fragility and risk associated with transmission systems in Busan and its neighboring regions, Ulsan and Gyeongnam. To achieve this, a network model of Busan’s transmission system was developed using OpenStreetMap data. Damage probabilities were calculated using seismic fragility curves from HAZUS and reports from the Ministry of the Interior and Safety. Damage state-specific risks were then quantitatively assessed by combining these fragility values with Busan’s seismic hazard curves. The results showed High Confidence and Low Probability of Failure values ranging from 0.049 g (Slight) to 0.273 g (Complete), with median fragility values ranging from 0.143 g (Slight) to 0.605 g (Complete). The annual risk for each damage state was determined to be 4.151×10-4/yr, 1.177×10-4/yr, 3.667×10-5/yr, and 9.391×10-6/yr. This research quantitatively assesses the seismic fragility of Busan’s transmission system, providing a practical basis for disaster response strategies and risk-informed decision-making related to regional electric power infrastructure.

지하 매설 수도관은 연약지반의 지반침하, 도심지의 부등침하, 싱크홀 등에 의한 허용한계를 초과하는 지반영구변형에 의해 손상이 발생할 수 있다. 지반변형으로부터 수도관을 보호하기 위한 관이음의 사용으로 수도시설의 안전성 확보가 요구된다. 따라서 매립 수도관의 과도 지반변형에 대한 안전성 평가를 위하여 다중적층형 벨로우즈를 신축관 이음으로 적용한 수도 배관시스템을 제작하 였다. 제작된 배관시스템의 굽힘 및 처짐에 대한 변형 성능 확인을 위하여 4점 굽힘 시험을 수행하였다. 4점 굽힘 시험 결과를 바탕으 로 국내 연약지반 모델을 고려하여 KS D ISO 16134에 따라 지반변형에 대한 안전성을 평가하였다. 안전성 평가 결과 다중적층형 벨로우즈 신축관 이음의 지반변형에 대한 성능은 매우 우수한 것으로 평가되었다.

In this study, static and dynamic analysis verification was performed to apply the fuel cell system to the E-PTO of the Wire aerial vehicle. First, structural analysis was performed to improve the weak points that occurred. Next, vibration analysis was performed on the fuel cell system for which structural safety review was completed according to the wide-band irregular vibration test standard. The analysis results showed that resonance occurred in a specific frequency band and local stress was high, so stiffness reinforcement was performed. After reinforcing the stiffness, stress was reduced through a decrease in transient response characteristics and resonance phenomenon.

This study aimed to improve safety and reduce labor intensity in offshore crab pot fisheries through the development of six types of automated fishing gear: a bait cutter, bait crusher, mainline arranging device, automatic pot hauler, cold water tank system, and crab pot unloading device. Sea trials demonstrated that both the bait cutter and bait crusher effectively reduced overall operation time. The mainline arranging device lowered the risk of injury compared to the conventional manual handling. The automatic pot hauler enabled the automated separation of crab pots, significantly decreasing the physical workload. The cold water tank system facilitated the efficient sorting of live crabs while enhancing onboard safety. Additionally, the crab pot unloading device reduced physical strain on workers and minimized catch damage. A satisfaction survey revealed high levels of approval among fishers, particularly regarding labor reduction and improved safety. Economic analysis indicated that vessels equipped with the automated gear experienced reduced overall operating costs. These findings suggest that the developed technologies will contribute to the long-term sustainability and modernization of offshore crab pot fisheries.

도시화로 인한 인구 집중은 다양한 도시 문제를 야기하고 있으며, 이에 따라 시민들의 쾌적하고 안전한 공간에 대한 수요가 증가하고 있다. 이러한 맥락에서 도시공원의 역할은 확대되고 있으며, 주간뿐 아니 라 야간 이용 역시 증가하는 추세이다. 그러나 공원 내 범죄는 주로 야간에 발생하는 경향이 있음에도 불구하고 야간 시간대를 대상으로 한 실증 연구는 부족한 실정이다. 본 연구는 CPTED 이론 중 영역성 의 하위 요소인 접근통제와 활동 지원 요인이 야간 안전성 인식에 미치는 영향을 분석하고자 하였다. 이를 위해 실제 야간 공원 방문자를 대상으로 설문조사를 실시하고 성별 및 연령에 따른 인식 차이를 검토하기 위해 빈도분석, 다중회귀분석, 분산분석을 수행하였다. 분석 결과 공원의 규모와 명확한 경계 는 모든 집단에서 공통적으로 야간 안전성 인식에 긍정적인 영향을 미치는 물리적 요인으로 나타났다. 여성과 고연령층은 시각적 식별성과 공간의 통제 가능성을 상대적으로 더 중시하는 경향을 보였으며, 활동 지원 요인에서는 남성은 도로 인접성과 외부 프로그램에, 여성은 편의시설 및 야간 이용 시설에 민감하게 반응하였다. 청년층은 개방성과 활동성을 중심으로 노년층은 시각적 단서와 생활 편의성을 중심으로 안전을 인식하는 특성이 확인되었다. 특히 일부 주민참여 프로그램은 낮은 참여율과 실효성 부족에 대한 불만으로 인해 오히려 야간 안전성 인식에 부정적인 영향을 미치는 것으로 분석되었다. 이러한 결과는 성별 및 연령에 따른 공간 인식 특성을 반영한 맞춤형 공원 설계의 필요성을 시사한다.

This study evaluated the safety impact of automated traffic enforcement cameras targeting tailgating behavior at signalized intersections by comparing traffic conditions shortly after installation and one year later. The Kukkiwon intersection in Gangnam-gu, Seoul, South Korea was selected as the study site. Individual vehicle speeds, accelerations, and subsequent distances were extracted from video data using YOLOv8 and ByteTrack, which are advanced deep learning-based object detection and tracking algorithms. Surrogate safety measures (SSM), such as time to collision (TTC), modified time to collision (MTTC), and proportion of stopping distance (PSD), were calculated to assess changes in traffic safety. Every SSM indicated an improvement one year after the installation of enforcement cameras, suggesting a reduction in collision risks. In particular, the PSD indicator showed a notable improvement, reflecting a better maintenance of safe following distances. These results highlight the effectiveness of automated enforcement in improving intersection safety and suggest its scalability to other intersections with similar tail-gating issues. Future research should explore the long-term and multisite effects using diverse intersection types and behavioral indicators.

Korea has many test beds where various mobility services are provided by automated vehicles. The test beds are operated in their operational design domain (ODD). However, disengagement frequently occurs, even in the ODDs of automated vehicles. In particular, human drivers have to take control of the automated vehicles at SAE Level 3 whenever the vehicles cannot drive by themselves because of an emergency or unknown factors. This study analyzed the driving safety of right turning at signalized intersections where automated vehicles face selfdriving issues because of potential conflicts with other vehicles, crossing pedestrians, and geometric factors. To conduct this analysis, we categorized right-turning intersections into two types with right-turning lanes and channelization islands and divided them into three sections, with a total of six sections. Subsequently, the six sections were compared with each other by disengagements of the automated vehicles as the key index to investigate their self-driving safety. Their significant differences indicate that ODD-related variables must be considered when designing and updating target test beds for automated vehicles.