In this study, a hybrid cooling system combining thermoelectric modules and a vapor compression cycle was applied to a cold storage unit, and the effect of enhancing energy efficiency through the application of mist spraying technology to the heat exchanger coils was analyzed. The hybrid cooling system was designed to operate the vapor compression cycle during the initial temperature reduction phase (from ambient to 5°C), and to maintain the set temperature using thermoelectric modules thereafter. Separate heat exchangers were installed for the thermoelectric and vapor compression components, and mist spraying was applied individually to each heat exchanger coil. Experimental results showed that mist spraying reduced power consumption by approximately 20% during vapor compression operation, and by about 1~2% during thermoelectric operation. This study empirically demonstrates the potential of mist spraying technology as an energy-saving enhancement for hybrid cooling systems, and the findings can serve as a foundation for the development and commercialization of integrated heat exchangers in the future.

This study empirically examines the effectiveness of the Ramsar Wetland City Accreditation System in promoting integrated management of urban-adjacent wetlands, enhancing community participation, and strengthening local capacity. Using survey and monitoring data from Jeju-si, Inje-gun, and Changnyeonggun (accredited in 2018) and Gochang-gun and Seogwipo-si (accredited in 2022), the analysis integrates AHP and statistical verification to evaluate system effectiveness, operational elements, and the relationship between performance and perception. The results indicate that the system positively contributed to establishing a supportive social foundation, including improved information accessibility (72%), strengthened community capacity (71%), enhanced conservation and management interest (83%), and greater public understanding of wetlands (84%), which in turn led to increased program participation and behavioral changes. Trust in local governments and management committees was relatively high, reinforcing regional governance. However, limitations such as inconsistent and discontinuous implementation, declining trust in central government, overreliance on local government initiative, and budget imbalances across project types were identified as constraints to sustainability. To address these issues, this study suggests establishing a scientific performance management system, expanding financial independence based on local resources, strengthening the authority of local management committees, improving evaluation quality, enhancing central-local cooperation, ensuring balanced budget allocation, and advancing information feedback systems, thereby supporting the evolution of Ramsar Wetland Cities as models of sustainable socio-ecological development.

This study experimentally evaluated the filter lifespan extension achieved by a retractable, built-in air purification system equipped with a self-cleaning rotating filter. Conventional fixed-type air purifiers commonly experience a rapid increase in pressure drop and non-uniform airflow distribution as dust accumulates on the filter surface, leading to degradation in long-term purification performance. To overcome these limitations, the proposed system incorporates a retractable filter module and a rotational dust-removal mechanism designed to maintain stable airflow and reduce particulate loading during extended operation. Experiments were carried out in a controlled 30 m3 residential-scale test chamber to compare filtration performance, pressure-drop characteristics, and particle removal efficiency between the self-cleaning retractable system and a conventional fixed-depth configuration. The results indicate that the rotating self-cleaning mode reduced pressure drop by up to 18.5% and improved PM2.5 removal efficiency by approximately 12.7% relative to fixed operation. Increasing the filter protrusion depth further enhanced airflow uniformity and expanded the clean-air coverage area, thereby delaying the onset of filter saturation. Overall, the findings demonstrate that the proposed retractable, built-in air purification system effectively suppresses pressure-drop rise, maintains purification efficiency, and extends usable filter life. These results confirm the system’s practical applicability for residential indoor-air-quality management and lay the foundation for future optimization and commercialization.

마늘의 파종 작업에 투입되는 노동력 및 노동시간은 마늘 재배 중 많은 비중을 차지한다. 이에 마늘 파종을 위한 기계가 개발 및 이용되고 있지만, 이중 파종과 결주 등으로 인해 동일 토지 대비 인력 파종에 비해 생산성이 감소하는 문제가 발생하고 있다. 따라서, 본 연구에서는 마늘의 기계 파종 생산성 향상을 목표로 파종기 결주율에 영향을 미칠 것으로 예상되는 파종시스템의 설계 및 운용 변수에 대한 이산요소 시뮬레이션을 수행하였다. 파종시스템에 이용되는 버킷의 형상 및 크기와 마늘의 이산요소모델은 기존 연구 결과를 활용하였으며, 이를 바탕으로 버킷의 회전속도, 간격 그리고 파종시스템의 경사가 결주율에 미치는 영향을 분석하였다. 시뮬레이션 분석 결과, 버킷의 회전속도와 간격은 결주율에 큰 영향을 미치지 않는 것으로 확인되었으나, 파종시스템의 경사는 결주율에 직접적인 영향을 미치는 것으로 확인되었다. 따라서, 파종기를 이용하여 마늘의 파종 작업을 수행할 경우, 파종기의 기울기 또는 토지의 경사 등을 고려해야 하며, 파종기 설계 시 경사조절장치 등의 도입을 통해 결주율 감소 및 생산성 향상에 효과적으로 대응할 수 있음을 확인하였다.

This study aims to quantitatively and qualitatively evaluate the operational effects of an emergency-vehicle preemption (EVP) system implemented in Anyang City and to derive improvement directions based on both empirical performance outcomes and user-experienced insights. Specifically, this study integrates three complementary methodologies: (1) controlled field tests comparing pre- and post-EVP travel performance under consistent traffic and signal conditions, (2) a one-year operational evaluation using 204 actual dispatch cases collected from six 119 Safety Centers, and (3) a structured survey of frontline firefighters who directly utilized the EVP system during actual emergency responses. The field test results indicated that the average travel time reduced by approximately 44% while the average travel speed increased by approximately 79%, with paired t-test verification confirming that the observed improvements were statistically significant and attributable to the EVP system instead of to random variations. Similarly, the operational evaluation indicated that the actual travel time reduced by an average of 49% compared with navigation-estimated values, whereas the golden-time (5 min) arrival rates for both fire/rescue and medical dispatches exceeded the regional average, with consistent performance demonstrated even under varying travel distances and road complexities. The firefighter survey further reinforced these findings, with respondents reporting clear improvements in golden-time achievement, reduced anxiety toward potential safety risks, and enhanced perceived safety during emergency trials, as well as identified several practical limitations such as route mismatches, occasional system malfunctions, and difficulty in perceiving preemption activation—factors that suggest necessary technical and operational refinements. In general, the EVP system was evaluated as an effective and highly practical tool that improves emergency-vehicle mobility, arrival-time stability, and operational reliability across diverse dispatch conditions. The combined quantitative and qualitative verification in this study underscores its value as a field-proven technology. Future studies should expand to multiregional longitudinal datasets, controlled analyses considering external variables such as traffic volume and weather, and quantitative evaluation of safety-related impacts such as reductions in intersection collisions or on-route risk exposure to assess the system’s broader policy and operational benefits more comprehensively.

As renewable energy penetration continues to increase, the output variability and forecasting uncertainty of photovoltaic generation have emerged as major operational risks in power systems. This study establishes a sensor-based data quality control procedure to ensure the reliability of meteorological data collected at a PV plant. For temperature, humidity, and wind speed, a four stage QC process physical range check, persistence check, step change check, and median filtering was applied. Solar radiation, which exhibits strong temporal and distributional characteristics, was processed using a three-stage QC procedure consisting of physical range, step change, and frequency distribution checks. Using the quality-controlled meteorological data, PV generation forecasting was performed with SVM and XGBoost models. As a result, the MAPE values improved to 6.32% for SVM and 6.08% for XGBoost after QC application. The findings confirm that meteorological data quality control significantly enhances PV forecasting accuracy and can support future strategies for distributed energy resource management, curtailment mitigation, and power system risk reduction.

Traffic congestion in tunnels, particularly phantom jams, significantly reduces driving efficiency and increases crash risks. To address this issue, a Pacemaker System (PMS) was implemented in the Geumnam Tunnel along the Seoul–Yangyang Expressway. A PMS aims to stabilize traffic flow and improve operational efficiency by guiding drivers to maintain uniform speeds through sequential LED illumination. This study aims to quantitatively evaluate the effectiveness of a PMS on traffic flow by analyzing Vehicle Detection System (VDS) data collected before and after its implementation. The analysis incorporated Level of Service (LOS) categories A–E, and distinguished between peak and non-peak hours to assess speed improvements and flow stabilization. The results indicated that the PMS increased the average speeds by approximately 6.5% across the LOS A–E conditions, with the most pronounced effects observed in LOS C–E. Furthermore, the speed distribution analysis revealed that the PMS enhanced lower-percentile speeds and reduced speed variance, thereby contributing to improved traffic stability. Statistical tests confirmed that the observed improvements were significant (p < 0.05). These findings demonstrate that the PMS effectively mitigates phantom jams and improves tunnel traffic efficiency, offering empirical evidence to support future PMS deployment and the development of tunnel traffic management policies.

This study was conducted to improve the stability of small barges used for remote bird monitoring at Capsosiphon fulvescens aquaculture farms. The monitoring accuracy is compromised by rolling and pitching motions induced by waves and wind. To address this problem, a damping system was developed to enhance barge stability. Field experiments were conducted at a farm to evaluate the effectiveness of the developed damping system. The rotational motions of the barge, with and without the damping system, were measured using a six-axis gyroscope sensor. The measurements were conducted at the Capsosiphon fulvescens farm located in Cheokchan-ri and Deokdong-ri, Gogeum-myeon, Wando-gun, Jeollanam-do across two periods: from October 5, 2024 to December 17, 2024 (Damping without) and from February 19, 2025 to April 15, 2025 (Damping with). The collected data were validated against wind speed records from the Korea Meteorological Administration. The results demonstrated that the damping system effectively reduced barge motion. Within a wind speed range of 0.1-9.0 m/s, the system achieved an average reduction of 7.11% in rotational motions. Its maximum performance was recorded at approximately 7.0 m/s wind speed where it achieved a reduction of 23.35%. These findings confirm the system significantly enhances barge stability and improves monitoring reliability.

항공기와 여객선과 같은 대형 여객 운송의 핵심 가치는 안전이며, 안전관리를 위해 국제조약을 기반으로 제정된 규칙에 따라 명시된 인원 이상의 훈련받은 승무원이 탑승해야 하는 공통점을 가지고 있다. 참사로 이어졌던 항공기와 크루즈 여객선 사고사례 분석을 통해 승무원의 역량과 교육 및 매뉴얼 관리가 안전에 지대한 영향을 미치고 있음을 확인하였으며, 사고 이후 관리부서를 일원화하고, 법 조항의 신설 및 강화와 함께 승무원 안전교육의 중요성이 대두되었다. 그러나 사고를 예방하고 비상 상황에 즉각 대응하기 위해서는 안 전교육 과정과 방식의 변화가 필요하며 이를 통해 교육 효과를 높여 승무원이 정확히 대응할 수 있도록 해야 한다. 첫째, 수직 형태의 구 조와 비슷한 공간의 반복, 화재 방지를 위해 닫힌 구조인 여객선의 공간적 특성은 여행객들이 쉽게 탈출하기 어려운 구조다. 따라서 이는 승무원의 공간적 이해의 중요성을 시사하며 탈출 교육에 확대 반영될 필요가 있다. 둘째, 항공기에 비해 승객의 이동 공간이 큰 여객선의 여객선 승무원의 비율을 높여, 안전관리 수행이 가능한 환경을 조성해야 하며 법률로 규제할 필요가 있다. 셋째, VR, 사이버, 메타버스 등 을 활용한 교육방식의 변화를 통해 승무원의 교육 효과를 높이고 실습 중심의 교육이 되어야 한다. 사고 사례분석을 통해 여객선 승무원 교육방식 및 방향 개선에 시사점을 제시했다. 이를 통해 대부분의 안전사고에 원인으로 지목된 인적요인 즉, 승무원의 안전관리 역량의 향상과 함께 대한민국 크루즈사업의 안전성 확보 및 완전한 성장에 기여하려 한다.

본 연구에서는 Romanoff(1957)의 실측 데이터를 사용하여 머신러닝 기반 상수도관의 부식 깊이를 예측하였다. 이를 실제 상수도관망에 적용하여 누적피해도를 분석하였다. 예측한 부식깊이를 사용하여 누적피해도를 분석하였으며 MCS(Monte Carlo Simulation)를 적용한 누적피해도와 비교 분석하였다. 부식깊이 예측모델에 따른 부식깊이를 분석한 결과 MLP-ReLU 모델이 가장 부식속도가 가장 빠르며 MLP-sigmoid가 가장 부식속도가 느렸다. 천안시 신방동과 성환읍 상수도관망에 MCS를 적용한 누적피해도 분석법과 머신러닝을 적용한 누적피해도를 비교 분석하였다. 신방동에서는 두 분석법 모두 2번 상수도관이 먼저 사용 한계에 도달하였으며 성환읍에서는 4번 상수도관이 가장 먼저 사용 한계에 도달하였다. 사용 한계에 가장 먼저 도달한 상수도관은 다른 상수도관보다 사용 년수가 오래되었거나 수압이 높은 것으로 확인되었다. MCS를 적용한 누적피해도 분석 결과 신방동의 경우 45년 만에 사용 한계를 초과한 반면 성환읍의 경우 47년 만에 사용 한계를 초과했다.

The concept of resilience has gained increasing attention amid growing urbanization and rising vulnerability to infrastructure. While various methodologies exist for evaluating the resilience of lifeline systems, few address the distinct structural features and failure modes of railway networks. This study refines existing approaches by incorporating characteristics unique to high-speed railways, with a focus on two key aspects. First, we define the structure of railway networks by identifying nodes and links, and deriving link-specific resilience criteria based on the fragility characteristics and recovery profiles of their structural components. Second, we utilize real data from the Korean railway system to quantify the performance degradation caused by component failures during seismic events. To assess the framework’s applicability, we use a simplified network and a more complex one integrating Korea’s Honam Line and Honam High-Speed Line. The framework effectively identifies critical scenarios and provides a valuable tool for decision-makers in assessing seismic risk and planning recovery for railway infrastructure.

본 연구는 MTS가 피부개선에 미친 영향에 관한 기존 연구들을 분석하여, 근거 체계를 구축하고, 주요 키워드 간 관계와 역할 및 패턴 등을 구조적으로 분석하고자 텍스트마이닝과 토픽모델링 및 단어네트워크 분석을 실시하였다. 관련 선행연구들은 MTS와 관련된 핵심 키워드와 연관 키워드를 혼합하여 전자도서관에서 검색하였으 며, 결론 부분의 Text를 수집하여 분석에 사용하였다. 분석결과는 다음과 같다. 첫 째, '피부', '효과', '실험', '관리', '개선' 등의 어휘가 주요 개념으로 확인되었다. 둘째, TF-IDF 분석에서 높은 가중치의 키워드들은 MTS의 피부 개선 효과에 관한 과학적 실험 기반 논의를 시사했다. 셋째, LDA 분석 결과, ‘과학적 검증 중심’과 ‘피부 개선 효과 중심’의 토픽2개로 나뉘었다. 넷째, 단어 네트워크에서 '피부'를 중심으로 '주름', '효과', '실험' 등이 강하게 연결되었고, '여성'과 '모공' 노드는 MTS가 여성 안면 부위 에 주로 적용됨을 나타냈다. 본 텍스트마이닝 기법은 유사 의료 미용 시술 분석에도 적용 가능하며, 향후 시계열 분석과 감성 분석을 통해 MTS 효과의 변화와 대상자 반응을 심층 탐색할 필요가 있다.

This study analyzed the structural performance of a microalgae-based lightweight ecological integration system for large-span structures to achieve carbon neutrality. To address the load problems of existing soil-based ecological systems, a lightweight system utilizing microalgae bioreactors was proposed, and structural performance was evaluated for four types of large-span structures: truss, arch, dome, and cable structures. Structural analysis results through finite element analysis showed that the proposed system achieved a 70% load reduction effect compared to existing systems, with structural performance improvements including 35-40% reduction in maximum deflection, 30-35% reduction in maximum stress, and 25-30% increase in natural frequency. Environmental performance analysis confirmed CO₂absorption capacity of 12-18 kg per m² annually and PM2.5 reduction effects of 15-25%. Economic analysis results indicated that benefits of 3.95-6.7 million KRW per year are generated for a 1,000 m²reference area, creating cumulative benefits of 179.75-227.5 million KRW over 25 years. Verification through the German BIQ House case confirmed CO₂reduction performance of 6 tons per year for 200 m², demonstrating the practical applicability of the system. This study presented the potential of an innovative ecological integration system that can ensure structural safety of large-span structures while simultaneously contributing to carbon neutrality.

Hydrogen has a wide flammability range and rapidly diffuses in air, making precision detection technology essential to prevent explosion risks and ensure system safety as the adoption of hydrogen infrastructure expands. Polymer materials are employed in such infrastructure to seal high-pressure hydrogen, and reliable measurement techniques capable of quantifying trace amounts of hydrogen permeating or leaking through these materials is necessary. In this study, a hydrogen quantification system combining volumetric analysis with image analysis was utilized to evaluate the hydrogen uptake and diffusivity of HDPE (high-density polyethylene), NBR (nitrile butadiene rubber), and EPDM (ethylene propylene diene monomer) under high-pressure conditions. The results indicated that HDPE and NBR samples containing silica filler exhibited hydrogen uptake behavior consistent with Henry’s law, while EPDM samples with carbon black filler demonstrated additional hydrogen adsorption on the carbon black surface. These research results provide a foundation for more precisely evaluating the permeation and leakage behavior of polymers in high-pressure hydrogen environments, and are expected to contribute to the safe and efficient development of hydrogen infrastructure.

This study presents energy-saving performance analysis of a recirculating aquaculture system (RAS) that uses seawater-source heat pumps to control the seawater temperature in the breeding tank. The analysis is based on artificial neural network (ANN) and TRNSYS-based digital twin simulations. The complex thermal load of the RAS, which fluctuates in real time due to changing environmental conditions, is simulated using the dynamic simulation software, TRNSYS. A fuzzy logic controller (FLC) was designed based on the dynamic heat load calculated by TRNSYS and the water temperature data of the breeding tank enabling capacity control of the inverter manipulator of the heat pump. At this stage, energy is saved through the control of the variable speed compressor responding to the partial load via the inverter. Power consumption was predicted at appropriate time intervals using a custom-built ANN model. The prediction results are used to determine the optimal number of heat pumps to operate. Through the digital twin simulation, the proposed heat pump capacity control is compared with conventional operating number control in terms of temperature regulation performance and power consumption. The results demonstrated that the proposed method can be easily implemented in Matlab and significantly improves energy efficiency in RAS farms.

확률론적 지진 안전성 평가(Probabilistic Safety Assessment)를 위해서 고장수목(Fault Tree) 기반 베이지안 네트워크(Bayesian Network, BN) 방법론이 제안된 바 있다. 해당 방법론은 시스템 구성요소들을 확률변수로 가정하고 변수들의 상관관계를 네트워크로 구축한 후, 변수들에 다양한 정보들을 입력함으로써 유연한 시스템 의사결정 수행이 가능하다는 장점이 있다. 그런데 이러한 시스템 평가를 위해서는 개별 요소들의 취약도 정보는 필수적이나, 플랜트 관련 설비들의 취약도 정보는 매우 한정적이다. 따라서, 우선적으 로 문헌조사를 수행하였고 Federal Emergency Management Agency(FEMA)에서 전체 시스템과 더불어 다양한 구조물 및 설비들의 취 약도 정보를 제공함을 확인하였다. 본 연구에서는 FEMA에서 제공하는 시스템 취약도와 개별 요소들의 취약도 정보를 기반으로 BN 을 통해 도출한 시스템 취약도를 비교･분석하는 것을 목표로 한다. 이를 위해 세 규모의 가스플랜트 Plot Plan을 정의하였고, 이에 대 응하는 BN 모델을 이용하여 시스템 취약도를 산출하였다. 세 규모에 대해 도출한 시스템 취약도와 FEMA에서 제공한 시스템 취약도 를 비교한 결과, 도출된 취약도가 보수적으로 산정됨을 확인하였고, 추가적으로 구축된 BN의 개별 설비들의 취약도 손상 상태 (Damage State, DS)를 변경해가면서 시스템 취약도를 산출한 결과 역시 FEMA에서 제시한 값보다 보수적임을 확인하였다. 이는 시스 템의 고장을 정의하는 DS 차이로 인한 결과이며 플랜트마다 모델링을 기반으로 하는 시스템 취약도 산출이 필요한 것으로 이해할 수 있다.

A high-pressure in-situ permeation measuring system was developed to evaluate the hydrogen permeation properties of polymer sealing materials in hydrogen environments up to 100 MPa. This system employs the manometric method, utilizing a compact and portable manometer to measure the permeated hydrogen over time, following high-pressure hydrogen injection. By utilizing a self-developed permeation-diffusion analysis program, this system enables precise evaluation of permeation properties, including permeability, diffusivity and solubility. To apply the developed system to high-pressure hydrogen permeation tests, the hydrogen permeation properties of ethylene propylene diene monomer (EPDM) materials containing silica fillers, specifically designed for gas seal in high-pressure hydrogen environments, were evaluated. The permeation measurements were conducted under pressure conditions ranging from 5 MPa to 90 MPa. The results showed that as pressure increased, hydrogen permeability and diffusivity decreased, while solubility remained constant regardless of pressure. Finally, the reliability of this system was confirmed through uncertainty analysis of the permeation measurements, with all results falling within an uncertainty of 11.2 %.