• Korean Journal of Agricultural and Forest Meteorology
• /
• v.15 no.1
• /
• pp.17-25
• /
• 2013

In this paper we interpreted the changes in wind field over complex mountainous terrains. The results of our study can be applied for predicting the direction of fire spread and for establishing strategies for fire prevention. The study area is bounded by $12{\times}12$ km domains of the Samcheok's long-term ecological research (LTER) site located in the east coast, in which a large-fire had occurred from 7 to 13 April 2000. Because of the area's complex topography, we compared the result of the Weather Research and Forecasting (WRF) mesoscale model with those observed by four automated weather stations. The WRF simulation overestimated the wind speed by 5 to 8 m/s (~200%) in comparison with those from four automated weather stations. The wind directions observed by the AWSs were from various directions whereas those from WRF model were mostly west wind at all stations. Overall, the simulations by the WRF mesoscale models were not appropriate for the estimation of microscale wind fields over complex mountainous areas. To overcome such inadequacy of reproducing the wind fields, we employed the ENVI-met model over Samcheok's LTER site. In order to test the model's sensitivity with the terrain effects, experimental simulations were conducted with various initial conditions. The simulation results of the ENVI-met model showed a reasonable agreement in wind speeds (about 70% accuracy) with those of the four AWSs. Also, that the variations in wind directions agreed reasonably well with changes in terrain effect. We concluded that the ENVI-met model is more appropriate in representing the microscale wind field over complex mountain terrains, which is required to predict fire spread and to establish strategies for forest fire prevention.

• Wind and Structures
• /
• v.30 no.6
• /
• pp.649-662
• /
• 2020

The existence of a dam has potential effects on the surrounding wind environment especially when it is located in mountainous areas. In this situation, the long-span bridge over the reservoir can easily be exposed to non-uniform incoming flows, affecting its wind-resistance performance. This paper presents a study on the aerostatic stability of such a bridge. Wind tunnel tests were first carried out to investigate the wind environment above a mountainous reservoir. The results show that the angle of attack and the wind speed along the bridge axis show obvious non-uniform characteristics, which is related to the inflow direction. When winds come from the south where the river is winding, the angle of attack varies along the span direction significantly. The finite element model for the bridge was established using ANSYS software, and effects of non-uniform wind loads on the aerostatic stability were computed. Non-uniform angle of attack and wind speed are unfavorable to the aerostatic stability of the bridge, especially the former. When the combined action of non-uniform angle of attack and wind speed is considered, the critical wind speed of aerostatic instability is further reduced. Moreover, the aerostatic stability of the bridge is closely related to the dam height.

• ETRI Journal
• /
• v.28 no.6
• /
• pp.796-798
• /
• 2006

This letter proposes a tapered stacked microstrip antenna for application in small unmanned aerial vehicles (UAVs), which has advantages in mountainous terrains. With its tapered structure and increased bandwidth designed to operate at the resonance frequency of 2.4 GHz, the proposed antenna improves directivity, accuracy, and precision of small UAVs. The test flight results show the proposed tapered antenna has a three times higher impedance capability of 350 MHz based on VSWR<2. The transmission pattern is also more reliable than that of previous antenna designs.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.2
• /
• pp.586-595
• /
• 1997

We proposea a more inproved alperithm which can reconstruct the berrer 3D terrains from cintour line data usong the fractals and the Neural Networks and which is an improvement based on that in[1, 2, 3]with the con-sideration on neighboring patch.We have learned the feature data in addition to reflecththe charateristics of complicated toprgraphy, and have implemented on mountainous and flatness topography using the proposed learning pattern by the reduced average error.The results of implements reprsented that the mountainous top-ography is better than that of fltness on the similarity and the visuality.

• Journal of the military operations research society of Korea
• /
• v.23 no.2
• /
• pp.155-170
• /
• 1997

Currently, increasing the number of artillery units requires more deployment space in FABA. However, available positions of artillery units in FEBA is limited due to mountainous terrains. Therefore, it is hard to find enough artillery position space in accordance with the field artillery mannual. This paper studies on determination of the size of battery position in order to maximize the firing-effectiveness and to minimize the enemy threat. Also, it studies the possibility of reducing the size of a battery position. The optimum size of a battery position id obtained by using Dantzig's model and Supper Quick II model which produces the probability of kill data with various input data. As a result, it shows that the size of battery position can be reduced without decreasing the firing-effectiveness.

• Journal of the military operations research society of Korea
• /
• v.18 no.1
• /
• pp.74-85
• /
• 1992

Increasing the number of artillery units requires more deployment space in the field operation area. However, there is limited space available in FEBA due to mountainous terrains. Therefore most artillery units cannot occupy enough deployment space which is proposed in the field artillery mannual(FM) to maximize the firing-effectiveness and to minimize the enemy threat. This paper studies the problems of reducing the size of a battery deployment space being applied currently without decreasing the firing-effectiveness of the battery. The optimum size of a battery position is obtained by using Lemus and David's allocation model and Supper Quick II Model which produces the probability of kill data with various input data. The result shows that the battery deployment space can be reduced without decreasing the firing-effectiveness in the example problem.

• Journal of Species Research
• /
• v.12 no.3
• /
• pp.224-228
• /
• 2023

Three wolf spiders of the family Lycosidae Sundevall, 1833 are newly described from Korea: Arctosa labiata Tso & Chen, 2004, Pardosa altitudis Tikader & Malhotra, 1980, and Pardosa laevitarsis Tanaka & Suwa, 1986. These spiders were collected during a seasonal survey of the spider fauna of National Parks located in Gangwon-do and Gyeongsanbuk-do in 2018-2019; two males of A. labiata from Mt. Songnisan National Park, one female of P. altitudis from Mt. Chiaksan National Park, and two males of P. laevitarsis from Mt. Odaesan and Sobaeksan National Parks. The three newly recorded spiders have previously been known to be distributed in Taiwan, India, China, and Japan. These spiders were collected by hand in mixed forest leaf litter in mountainous terrains. The present paper taxonomically describes these three wolf spiders with measurements and morphological illustrations.

• International Journal of Highway Engineering
• /
• v.13 no.4
• /
• pp.221-229
• /
• 2011

Road design needs to ensure the economic justification and the preservation of nature by adapting road alignment to the natural terrain. Though current road design guideline only defines a flat and a mountainous terrain, classification including rolling terrain should be needed while considering the fact that about 25.8% of our land can be classified as rolling and the road design guideline of developed countries such as United States and Australia has a terrain classification including rolling in order to take a deep consideration on the natural environment. The study attempts to draw a criterion to classify the assumed three individual terrains in a quantitative way by using a index like the undulation of the original ground profile. The study carried out a case study based on a conceptual frame developed in the study as an approach to differentiate each terrain. As a result, the study suggests a criterion in that a flat terrain has less than 40 meters in the difference between the highest and the lowest point of original ground from 40 to 60 meters for rolling terrain, and greater than 60 meters for mountainous respectively.

• Journal of Korean Society of Disaster and Security
• /
• v.13 no.3
• /
• pp.45-58
• /
• 2020

Due to a high portion of mountainous terrains in Korea, debris flow and its disasters have been increased. In addition, recently localized flash-floods caused by climate change should add frequencies and potential risks. Grasping and understanding the behaviors of debris flow would allow us to prevent the consequent disasters caused by its occurrence. In this study, we developed a number of cases by changing the bottom slopes and their curvatures and investigated their effects on potential damage caused by the debris flow using FLO-2D. As simulating each bed slopes we analyzed for velocity, depth, impact, reach distance, and reach shape. As a result the lower the average slope, the greater the influence of its curvature and the numerical results were analyzed with showed a well-marked difference in impact stress and flow velocity. The result from this study could be referred for protecting from the debris flows when design countermeasure structures in mountainous regions.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.11 no.3
• /
• pp.87-93
• /
• 2008

In order to manage national environment effectively, one has to understand its ecological traits. The difference of temperature determines ecological traits of each respective region. In other words, temperature differentials on surface make a great impact on botanical structure. Currently, isothermal data-produced by meteorological stations based upon time series analysis-are widely used to plan and manage national environment. Nonetheless, the isothermal data do not reflect real surface temperature of regions. Because of numerous mountainous terrains in the Korean peninsula where temperature varies widely according to altitude, the range of temperature distribution-that reflects altitudinal change-has to be paid special attention. This study aims at expressing in space isothermal distribution that is necessary to plan and manage national environment effectively. In addition, not just South Korea, but also North Korea was included for isothermal distribution. As a result, this study corrected established isothermal lines up to date and demonstrated that altitude, latitude, and distance from coastal lines greatly influence temperature distribution of the Korean peninsula.