Performance of the hydrogen fuel cell system in a compact special vehicle is mainly influenced by the thermal characteristics of heat release through air flow with electrochemical mechanisms. In this study, numerical analysis has been carried out to investigate air flow and heat transfer characteristics near the fuel cell system for various operating conditions. The cooling characteristics around the radiator system depend on air flow generated by vehicle movement, and the effects of vehicle-induced air flow on the velocity and temperature distributions within the heat release system were examined. These results showed that there are quite complicated air flow around the radiator and fan near the fuel cell system in the vehicle cargo area, and its efficient flow field resulted in cooling performance improvement with driving speed. Hence overall heat release characteristics of the hydrogen fuel cell system are strongly associated with various air flow behavior formed around the compact special vehicle including cargo area.

본 연구에서는 작물 이미지 데이터셋에 적합한 데이터 증강 기법으로 자연광 기반 증강을 제안하였다. NLA는 밝기, 색온 도, 대비 변화를 반영하여 실제 환경에서 발생 가능한 광조건 을 학습 데이터에 적용함으로써, 기존 YOLO 기본 증강 대비 더욱 현실적인 학습 데이터를 생성할 수 있도록 설계되었다. 참외와 딸기 데이터셋을 대상으로 한 실험 결과, NLA는 Baseline 대비 전반적인 성능 향상을 보였다. 또한 Baseline에 서 학습 후반부에 나타난 성능 저하나 불안정성이 NLA에서 는 완화되어, 제안 기법이 과적합 방지와 학습 안정성 유지에 도 효과적임을 입증하였다. PatchSwap은 Mosaic의 한계를 보완하기 위한 보조적 시도로 실험에 포함되었으나, 종합적 인 성능 향상에는 뚜렷한 기여를 하지 못하였다. 본 연구 결과는 작물 이미지에서 실제 광조건을 반영한 데 이터 증강의 필요성과 유효성을 보여주었으며, 이는 향후 다 양한 작물과 촬영 환경으로 확장 가능한 가능성을 제시한다. 앞으로는 NLA의 적용 범위를 확대하고, 다른 딥러닝 모델 및 추가적인 농업 데이터셋에 대한 성능 검증을 통해 본 기법의 범용성과 실효성을 더욱 강화할 필요가 있다.

Aerial work platforms (AWPs) are specialized vehicles designed for tasks at elevated heights, and are widely used in various environments such as construction sites, road maintenance, and high-altitude operations. In this study, computational fluid dynamics (CFD) analysis was conducted to investigate the airflow field, drag force, and torque characteristics around an AWP. The simulation results showed that the overall airflow velocity decreased as it passed over the vehicle and boom, while it increased locally between the vehicle and the boom, and beneath the work platform. The drag force and torque acting on each component were highly sensitive to changes in boom angle due to variations in airflow. As the boom angle increased, the drag force increased by approximately 20 times, and the torque by up to 108 times. These findings provide fundamental data for establishing design criteria to enhance the structural stability and aerodynamic performance of aerial work platforms.

Seafood, a major source of essential protein for human nutrition, has gained increasing significance as consumption rises due to higher income levels, growing health awareness, and environmental concerns. This study investigates the effects of individual lifestyles, food consumption tendencies, and food safety concerns on seafood consumption behavior. Utilizing data from the 2022 Food Consumption Behavior Survey conducted by the Korea Rural Economic Institute, the analysis categorizes consumers by age group to account for the nonlinear relationship between age and seafood consumption. Key variables include seafood purchase frequency, demographic characteristics, food safety concerns, and dietary preferences. The results reveal that seafood consumption patterns vary significantly across age groups, highlighting the importance of age-specific marketing strategies. Moreover, the findings suggest a need to expand and strengthen the promotion of food safety certification systems and to develop more targeted promotional strategies that reflect the diverse characteristics of individual consumers.

Toilet liquid-type cleaners utilize operating technology that employs buoyancy mechanism to inject uniform amount of cleaning solution. Flow characteristics of velocity and pressure distributions in the flow field of toilet flush cleaner injection device have been analyzed with CFD method. The flow rate decreases near the inlet of the system, where it contacts the container of the cleaning liquid bottle. It then increases near the injection device stopper and decreases again as it moves toward the system outlet The height of the cleaning solution decreases from 12 cm to 3 cm when using the spray device, the average outlet velocity decreases by approximately 73%. The solution level difference increases from 1.616 cm to 3.216 cm, the inlet velocity decreases by approximately 4.1%~5.6%. These predicted results can be widely applied as basic conceptual design data for highly efficient toilet flush cleaner injection device.

Aerial work platform truck is used in various ways depending on the surrounding environment, of city roads, farming areas, and industrial sites. Air flow, drag force and torque in surroundig the flow field of AWP have been analyzed with CFD method. The overall air flow rate decreases as the AWP passes and increases between the vehicle and the boom, at the boom connections, and at the bottom of the work platform. The drag force and torque on the boom, workspace, and the combined boom and workspace are largely affected by air flow velocity. The boom's drag and torque are approximately 2.2 and 1.3 times greater than those of the work platform, respectively. These predicted results can be widely applied as basic conceptual design data for highly efficient aerial work platform truck.

In this study, power generation characteristics based on water flow dynamics in a pipe system with a mobile firefighting robot were analyzed using 3D CAD modeling and computational fluid dynamics(CFD) simulations. The water flow field which is significantly affected by applied pressure, generates mechanical torque at the turbine blades, enabling power generation. The inlet pressure of the flow field was set to approximately 6 to 12 bar, and the flow characteristics such as velocity, pressure, and mass flow rate, along with power generation characteristics, were analyzed under various turbine rotational velocities. It was observed that higher inlet pressures resulted in increased torque and mechanical power output at the turbine blades. This research is expected to serve as a fundamental design and data reference to improve the performance of firefighting robots at fire sites.

The Climate chamber system is an essential facility for aerodynamic performance development of commercial vehicles to investigate air flow field characteristics in different climatic conditions. In particular, the analysis of airflow fields within the chamber system is an essential consideration for optimal design. In this study, the pressure characteristics and velocity uniformity in the test section area were predicted with blower impeller rotational speed using CFD. The velocity uniformity is affected by the distance from the blower nozzle outlet, reaching up to 72.7% at 695 RPM. The pressure differential between 300 RPM and 740 RPM shows an approximate difference of 2651 Pa, with a high-pressure distribution observed along the right side wall of the blower. These results are expected to be used as design data applicable for improving the performance of environmental chamber systems.

Air flow field characteristics in a compact chamber system are indispensable for the efficient development of vehicle aerodynamic performance. In this study, air flow and velocity uniformity in the chamber system were numerically analyzed using the CFD method. Air flows at a uniform velocity from the outlet of the blower, passes fast through the heat exchanger with partial pressure difference, and then moves into the blower inlet. Overall pressure drop through the fan gradually increases with the flow rate. The uniformity varies along the test section, decreasing by 5-10% with distance from the nozzle. These predicted results can be widely used as basic conceptual design data for an efficient vehicle chamber system.

Recently injection mold processing is necessary for the development of efficient solar concentrator system with a Fresnel lenses. Heat transfer mechanism in the Fresnel lens manufacturing process have a significant influence on precision machining and optical performance of solar power generation. In this study, we analyzed the thermal characteristics of temperature and heat flux distributions near the lens for transient molding process using CFD method. Initially for one second fast temperature variation on the upper surface of the lens leads to high heat flux distribution. It is gradually cooled to around 128℃ over a period of 60 seconds which is largely affected by the mold structure and the characteristics of the cooling lines. There is also high heat flux occurred on the lens upper side and lower surfaces with rapid temperature change. These results can be applied as fundamental design data for the manufacturing process in the development of Fresnel lenses.

Air blower has been widely used in many industrial fields such as wind tunnel and large ventilation systems. Its performance is affected by operating conditions and system geometry of inpeller and duct, and these design parameter optimization is essential for the effective development. CFD analysis is carried out to investigate the air flow field characteristics with outlet total pressure in a blower system. Intake air into the impeller blade through the inlet is compressed, and then gradually discharged from the outlet with ascending total pressure, and predicted results are compared with test data. Especially this overall pressure difference in the blower system severely depends on the flow rate. These results are expected to be used as applicable design data for blower performance improvement.

Application areas of floating marine structure systems have been increased with the development of power generation systems using renewable energy. Hence it is necessary to analyze the behavior of these floating systems for efficient design and operation. In this study, a computational analysis was performed to predict the characteristics of mooring lines load variation connected to a floating marine structure with waves. Pressure on the floating body and mooring lines load were analyzed with wave direction and height. The floating body stability severely decreased for 90° of the wave incident direction, and maximum load of the mooring lines increased with the height. These results are expected to be applicable for optimal design of the marine floating system.