• Journal of The Geomorphological Association of Korea
• /
• v.21 no.4
• /
• pp.41-52
• /
• 2014

Coastal dune, as one part of beach system, contributes for beach recovery as well as preventing beach erosion by exchanging sands between beach and dune. Due to high tidal range, the boundary of sand dunes on the west coast of Korean Peninsula is outside the high water line during spring tide and erosion also occurs in high waves during spring high tide. This paper investigates the erosion status of the dunes located in the JangHang beach by analyzing images from camera monitoring system, and tide and wave data observed adjacent to the study site during the passage of 4 typhoons in 2012. It also studies the benefits of camera monitoring images in investigating the dune erosion and analyzing coastal topographic changes.

• Journal of Aerospace System Engineering
• /
• v.16 no.6
• /
• pp.64-73
• /
• 2022

This study aimed to design a 3D fairing shape to reduce the air resistance of commercial vehicles. Rankine Half Body was applied to design the fairing shape, and the design was verified through aerodynamic analysis. Aerodynamic loads were calculated considering the speed conditions of commercial vehicles and gust conditions to ensure the structural safety of the fairing. A glass fibre/epoxy composite material was used to design a fairing structure that satisfied the safety factor 3. The structural safety of the lightest fairing was confirmed through structural analysis.

• Journal of Aerospace System Engineering
• /
• v.16 no.2
• /
• pp.25-32
• /
• 2022

A cab roof fairing is a device that reduces the drag coefficient of a commercial vehicle, by controlling the resistance of flow separation occurring in the front when the commercial vehicle travels. Commercial vehicles are designed to facilitate aerodynamic resistance that cannot be avoided from the driving direction of the vehicle, because they must structurally load containers in the rear. For this reason, it is closely related to oil costs and environmental pollutants. In this study, the 3D fairing shape was designed based on the Rankine half body theory, and the design results were verified through aerodynamic analysis.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.23 no.6
• /
• pp.191-197
• /
• 2023

The farming diary has significant value for farmers as it serves as crucial documentation, supporting evidence for eco-friendly and GAP (Good Agricultural Practices) certifications, as well as when applying for diverse subsidies. A detailed farming diary holds immense value, yet many farmers face challenges in document preparation, so even though training is provided on how to write a farming diary, making these remains impracticable for some. Therefore, this paper suggests using ChatGPT as a solution, enabling the effortless addition of comprehensive information to existing farming diary. With this method, it is expected that enhancing the thoroughness of the farming diary will significantly amplify its worth as robust certification evidence, thereby providing substantial support for future farming endeavors.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.11 no.4
• /
• pp.145-151
• /
• 2006

The water line moving on the intertidal flat during a flood indicates depth contours between low and high water lines. The water lines extracted from the consecutive images are rectified to get the ground coordinates of each depth contour and integrated to provide three dimensional information of Intertidal flat topography. The tidal flat outside Saemankeum-1 sea dike shows the most obvious changes of tidal flat topography after the construction of sea dikes. This tidal flat topography was observed using digital camera images, and the calculated depths were very similar to in-situ measurement data. Topography changes obtained from two different period data were also examined.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.13 no.1
• /
• pp.56-66
• /
• 2008

Subtidal surface currents are derived from HF radar measurements in the Saemangeum coastal ocean of the Yellow sea in July 2002 and from September to November 2004. The surface current field is analyzed to examine the effect of wind, river plume and coastline change on the spatial distribution and temporal variation of the surface currents. In July 2002, average wind speed was 0.5 m/s and freshwater discharge from the Keum River was $0.88{\times}10^7\;ton/day$. Temporal mean currents ($\overline{U}$) flow to the northwest with speed of $7{\sim}10\;cm/s$ near the Keum River estuary, to the west as fast as 13 cm/s near the opening gap of the Saemangeum $4^{th}$ dyke, and to the northwest off the Gogunsan-archipelago. This flow pattern is a result of the Keum River plume dispersal and tide-residual currents from the opening gap of the Saemangeum $4^{th}$ dyke. Time series of spatially-averaged current (<$U-\overline{U}$>) direction is highly (r=0.98) correlated with wind direction. From September to November 2004, the opening gap of the Saemangeum $4^{th}$ dyke was closed, northwesterly wind blew with speed of 2.5 m/s on average and the Keum River discharge was $1.19{\times}10^7\;ton/day$. Temporal mean current field ($\overline{U}$) has weak surface flow in most of the coastal ocean and relatively strong currents flow to the southwest with speed of 10 cm/s along the shape coastline of the Gogunsan-archipelago and the Saemangeum $4^{th}$ dyke. The strong flow is generated by the prevailing northwesterly wind which pushes the Keum River plume toward the Saemangeum $4^{th}$ dyke. The residual currents from the opening gap of the Saemangeum $4^{th}$ dyke disappeared and correlation coefficient between time series of spatially-averaged current () direction and the wind direction is 0.69.