• Wind and Structures
• /
• v.20 no.3
• /
• pp.405-422
• /
• 2015

In previous model- and full-scale studies, high-amplitude vertical vibrations of mast-arm traffic signal structures have been shown to be due to vortex shedding, a phenomenon in which alternatingly shed, low-pressure vortices induce oscillating forces onto the mast-arm causing a cross-wind response. When the frequency of vortices being shed from the mast-arm corresponds to the natural frequency of the structure, a resonant condition is created causing long-lasting, high-amplitude vibrations which may lead to the fatigue failure of these structures. Turbulence in the approach flow is known to affect the cohesiveness of vortex shedding. Results from this full-scale investigation indicate that the surrounding terrain conditions, which affect the turbulence intensity of the wind, greatly influence the likelihood of occurrence of long-lasting, high-amplitude vibrations and also impact whether reduced service life due to fatigue is likely to be of concern.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.509-522
• /
• 2010

There is a increasing trend in disaster occurrence due to steep-slope failures in urban area during typhoon and torrential rain season in Korea. The underlying hazards that cause slope failure are mainly linked with urbanization and industrialization. To minimize the disaster damages by slope failure, objective and unified evaluation approached are desired. Since currently available evaluation checklists are developed for specific purposed, there is a limitation to adapt those checklists for stability evaluation in natural terrain. This study proposes an improved evaluation checklist based on the comparison of previous checklists and applicability and feasibility are analyzed implementing field application.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.18 no.3
• /
• pp.225-231
• /
• 2000

Soil loss by the rains has effect on natural environment. But It is difficult to find out the data that is surveyed in watershed. In this study, we combine RUSLE and GSIS, develop a program to automatically extract geo-factors to predict soil loss, and perform recurrent analysis against actual sediment load to bring out the relativity between soil loss and sediment load. Each factors need to RUSLE conducted by grid analysis. As the process to extract terrain factor became programming, the efficiency is rised.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.27 no.5
• /
• pp.57-65
• /
• 2000

Vernacular embodies a culture and economy that are unique to one particular region at a given period, expressed in the lifestyles of the ordinary people of the region. This study aims at interpreting Korean Vernacular Landscape by applying the analytical tool thus developed to the lifestyles of ordinary people found in their permanent dwellings (e. g., villages). By so doing, this study hopes to contribute to building a framework with which to understand the tradition of ordinary people by exploring the uniqueness and basic characteristics of Korean Vernacular Landscape. This study relies primarily on filed studies on, and publications relating to, the agrarian and residential landscapes. The Korean vernacular landscape has not only crude and simple generality, but also individuality derived from cultural circumstances and natural feature. Korean Vernacular Landscape may be characterized as the practical Vernacular Landscape, consisting of the raw materials that were only available in a particular region, shaped by the terrain, and maintained by the customs that varied from a region to a region.

• Proceedings of the KSR Conference
• /
• 2006.11b
• /
• pp.392-401
• /
• 2006

In the July of 2006, devastating rainfalls ravaged the terrain in the province of Kangwon. These rainfalls resulted in debris flows, landslide and overflow over the habitat. Following these events, the urgent field study and countermeasures were to be needed and several methods were indicated. At each site, field observations were made and the properties of the channel and debris flow were broadly characterized. Debris flows are a natural hazard which looks like a combination of flood, land and rock slide. The same goes for that case, debris flow has been reported frequently overseas and the extent of damages has been increased. But the hazards "debris flow" is still insufficiently researched and futhermore debris flows are very hard to predict. In this paper, the general overview of the debris flow problem and the mitigation method will be presented

• Journal of Forest and Environmental Science
• /
• v.26 no.3
• /
• pp.181-192
• /
• 2010

Water erosion is progressing in the Loess Plateau, especially in gullies, and the sediment runoff to the Yellow River amounts to 975 million tons every year. Natural factors for water erosion include climate, soil, geological feature, terrain and vegetation. Many development projects due to the increasing population reduced the forest coverage ratio to 10%, and 200 million people in the downstream area are suffering from the damage during intense rainfall. Accordingly, the Chinese government is continuously trying to efficiently prevent the erosion by establishing measures for water erosion, including fish-scale pits, terrace technique, and check dams.

• Journal of Environmental Science International
• /
• v.32 no.5
• /
• pp.375-384
• /
• 2023

Climate data were obtained over an eight-year period (July 2013 to June 2021) using an automatic weather observation system (AWS) installed at the foot of Mt. Geumo in Chilgok, Gyeongbuk. Using climate data, the statistical and meteorological characteristics of the local circulation between the Nakdong River and Mt. Geumo were analyzed. This study is based on automatic weather observation system data for Dongyeong, along with comparative climate data from the Korea Meteorological Administration (Chilgok) and the Gumi meteorological observatory. Over the eight- years, mountain and valley winds have occurred 48 times a year on average, with the highest occurring in May and the weakest winds in June and December. When mountain winds occurred, the temperature in the nearby lowland region more strongly decreased than when valley winds blew. However, the potential to use mountain winds to improve urban thermal environments is limited because mountain winds occur infrequently in summer when a drop in nighttime temperature is required.

• International conference on construction engineering and project management
• /
• 2017.10a
• /
• pp.242-244
• /
• 2017

Excavation for construction is implemented in natural geographical terrain using a variety of construction equipment. Therefore, 3D excavation simulation requires integration of geographical and equipment modeling. This paper proposes a technique that integrates geographical and equipment modeling for 3D simulations of construction excavation. The geographical model uses a digital map to show ground surface changes during excavation and the equipment model shows equipment movement and placement. This combination produced a state of the art 3D simulation environment that can be used for machine guidance. An equipment operator can use the 3D excavation simulation to help construction equipment operators with decisions during excavation work and consequently improve productivity.

• Korean Journal of Remote Sensing
• /
• v.36 no.5_4
• /
• pp.1209-1220
• /
• 2020

In the case of forest areas, the installation of ground control points (GCPs) and the selection of terrain features, which are one of the unmanned aerial photogrammetry work process, are limited compared to urban areas, and safety problems arise due to non-visible flight due to high forest. To compensate for this problem, the drone equipped with a real time kinematic (RTK) sensor that corrects the position of the drone in real time, and a 3D flight method that fly based on terrain information are being developed. This study suggests to present a method for investigating damage using drones in forest areas. Position accuracy evaluation was performed for three methods: 1) drone mapping through GCP measurement (normal mapping), 2) drone mapping based on topographic data (3D flight mapping), 3) drone mapping using RTK drone (RTK mapping), and all showed an accuracy within 2 cm in the horizontal and within 13 cm in the vertical position. After evaluating the position accuracy, the volume of the landslide area was calculated and the volume values were compared, and all showed similar values. Through this study, the possibility of utilizing 3D flight mapping and RTK mapping in forest areas was confirmed. In the future, it is expected that more effective damage investigations can be conducted if the three methods are appropriately used according to the conditions of area of the disaster.

• Journal of the Korea Computer Graphics Society
• /
• v.23 no.1
• /
• pp.33-38
• /
• 2017

In this paper, we suggest a method to simulate high-quality iguana animation by using low-quality motion capture data. Iguana motion data captured using a small number of markers cannot express its movement precisely, and even with a realistic skin mesh, it shows unnatural movement because of limited degrees of freedom. In order to solve this problem, we propose to simulate a natural and flexible movement by applying a soft-body simulation technique which models the movement of an iguana according to muscle forces and body's elastic forces. We construct a motion graph from the motion capture data to describe the iguana's various movements, and utilize it to select appropriate movements when the iguana moves. A target point on a terrain is set from the user's input, and a graph path is planned based on it. As a result, the input movement of iguana walking on a flat ground transforms to a movement that is adapted in an online manner to the irregular heights of the terrain. Such a movement is used to calculate the ideal muscle lengths that are needed for soft-body simulation. Lastly, a tetrahedral mesh of the iguana is physically simulated to adapt to various situations by applying a soft-body simulation technique.