• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.2
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• pp.18-24
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• 2023

According to the results of a survey by Boeing, LOC-I (Loss of Control in Flight) was the highest in the number of deaths by fatality accident category in the past 10 years from 2012 to 2021, and the number of deaths worldwide due to LOC-I accidents was 757. It turned out to be the biggest cause of aircraft fatalities, with a figure close to twice the sum of UNK (Unknown or Undetermined), which is the 2nd place, and CFIT (Controlled Flight Into or Toward Terrain), which is the 3rd place. This study set six scenarios related to spatial disorientation that may occur during sensory-dependent flight targeting student pilots and instructor pilots at domestic designated specialized educational institutions using flight simulation training equipment, and in each scenario, the pilot's. The need for SDRT (Spatial Disorientation Recovery Training) is verified by analyzing the flight experience and recovery ability by qualification, and SDRT is repeatedly performed to verify and present the training cycle and time.

• Journal of the Korean Institute of Rural Architecture
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• v.26 no.2
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• pp.27-36
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• 2024

Many houses have been left vacant in cities worldwide due to changes in the economy, society, and urban composition. The increase in vacant houses causes social problems and decrease in the value of real estate. Considering the cost of preparing a new residence because the existing residence no longer functions, it is an important problem to solve empty houses in the existing residence. Accordingly, policy attempts and studies to reduce and utilize vacant houses are in progress in various countries. In South Korea, the ratio of vacant houses was 6.4% of all houses as of 2021, and in Jeolla-buk-do, it was 11.6%, which is higher than the national average. Jeollabuk-do conducted a fact-finding survey on countermeasures against vacant houses; 17,732 vacant houses (2.4%) were surveyed. The urbanization, population, and terrain of Jeollabuk-do, consisting of 14 cities and counties, were considered. The ratios, types, grades, and spatial autocorrelations of vacant houses were analyzed after classification into city areas (focus, small, and medium) and county areas (plains and mountains) areas to derive policies according to the distribution of vacant houses. The average difference in ratio, type, grade, and spatial autocorrelation of vacant houses was used to analyze the characteristics of the distribution of vacant houses according to these classifications. There were significant differences in the averages of the ratios, grades, and spatial autocorrelations between city and county areas. The autocorrelation of vacant house distribution exhibited differences between urban and county areas.

• Journal of Korean Society of Forest Science
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• v.96 no.3
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• pp.251-258
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• 2007

Airborne Lidar (light detection and ranging) can be an effective alternative in forest inventory to overcome the limitations of conventional field survey and aerial photo interpretation. In this study, we attempt to develop methodologies to identify individual trees and to estimate tree height from airborne Lidar data. Initially, digital elevation model (DEM) data representing the exact ground surface were generated by removing non-ground returns from the multiple-return laser point clouds, obtained over the coniferous forest site of rugged terrain. Based on the canopy height model (CHM) data representing non-ground layer, individual tree heights are extracted through pseudo-grid method and moving window filtering algorithm. Comparing with field survey data and aerial photo interpretation on sample plots, the number of trees extracted from Lidar data show over 90% accuracy and tree heights were underestimated within 1.1m in average at two plantation stands of pine (Pinus koraiensis) and larch (Larix leptolepis).

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.4
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• pp.28-38
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• 2004

Korean goral (Nemorhaedus caudatus raddeanus) is one of the endangered species in Korea, and the rugged terrain of the Soraksan National Park (373㎢) is a critical habitat for the species. But the goral population is threatened by habitat fragmentation caused by roads and hiking trails. The objective of this study was to develop a potential habitat suitability model for Korean goral in the park, and the model was based on the concepts of fuzzy set theory and multi-criteria evaluation. The process of the suitability modeling could be divided into three steps. First, data for the modeling was collected by using field work and a literature survey. Collected data included 204 points of GPS data obtained through a goral trace survey and through the number of daily visitors to each hiking trail during the peak season of the park. Second, fuzzy set theory was employed for building a GIS data base related to environmental factors affecting the suitability of the goral habitat. Finally, a multiple-criteria evaluation was performed as the final step towards a goral habitat suitability model. The results of the study were as follows. First, characteristics of suitable habitats were the proximity to rock cliffs, scattered pine (Pinus densiflora) patches, ridges, the elevation of 700∼800m, and the aspect of south and southeast. Second, the habitat suitability model had a high classification accuracy of 93.9％ for the analysis site, and 95.7％ for the validation site at a cut off value of 0.5. Finally, 11.7％ of habitatwith more than 0.5 of habitat suitability index was affected by roads and hiking trails in the park.

• 한국지구물리탐사학회:학술대회논문집
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• 1999.08a
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• pp.21-36
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• 1999

Recently resistivity survey is widely used for site investigations in the field of civil engineering. Since such application area requires accurate interpretation tools especially in the area of complicated geology and rough terrain topography, we developed a three-dimensional (3-D) resistivity inversion code, which can reconstruct real earth structures. Furthermore, the inversion code gives resolution-enhanced images by applying the ACB(Active Constraint Balancing) method. With the help of this inversion code, 3-D resistivity survey is now used as new techniques for site investigations in civil engineering problem. By imaging the 3-D resistivity distribution, we could get useful informations such as depth distribution of basement rock, distribution of weak zone, fractures and cavities which is crucial to civil engineers.

• Journal of Korean Society of Rural Planning
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• v.15 no.3
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• pp.61-79
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• 2009

This study discusses developing ecological trails and route alignment in mountainous rural area. Through a process of ecological resources survey, ecological trails and route alignment has been established. Mainly, by focusing on ecological resources in rural areas, it was indifferent to their own ecological resource and charm to make it unique strengths. Based on survey the results, Natural ecology resources, there were the climate factor, surface, geological, terrain analysis. Furthermore, ecological resources were researched and analyzed the elements of it, distribution of resources, types, location, semantic analysis. The results are expressed on the map and recorded by taking pictures. Plant ecosystem, there were actual vegetation, land use, flora analysis. Wild animal ecosystem, it was checked and recorded on 1/1,000 map partition the emergence of wild birds, the number of species distributed by foraging guild, the emergence of amphibians, reptile, mammals and insect species. The site is chosen as rural theme village in 2007, base on their own rich ecological and landscape resources. Therefore, we carried out ecological trails and route alignment plan in accordance with analyzed the natural ecological resource and after setting up the basic goal, ecological trail has been composed and planting has done and direction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.592-597
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• 2020

Currently, river survey data is mainly performed by acquiring longitudinal and cross-sectional data of rivers using total stations or the GNSS(Global Navigation Satellite System). There is not much research that addresses the use of LiDAR(Light Detection and Ranging)systems for surveying rivers. This study evaluates the applicability of using LiDAR data for surveying rivers The Ministry of Land, Infrastructure and Transport recently launched a drone-based river fluctuation survey. Pilot survey projects were conducted in major rivers nationwide. Studies related to river surveying were performed using the ground LiDAR(Light Detection And Ranging)system.Accuracy was ensured by extracting the linearity of the object and comparing it with the total station survey performance. Data on trees and other features were extracted to generate three-dimensional geospatial information for the point-cloud data on the ground.Deviations were 0.008~0.048m. and compared with the results of surveying GNSS and the use of drone LiDAR data. Drone LiDAR provided accurate three-dimensional spatial information on the entire target area. It was able to reduce the shaded area caused by the lack of surveying results of the target area. Analyses such as those of area and slope of the target sites are possible. Uses of drones may therefore be anticipated for terrain analyses in the future.

• The Journal of Engineering Geology
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• v.23 no.1
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• pp.57-65
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• 2013

We developed a computer program (CDFlow v. 1.0) to design countermeasures against debris flows in natural terrain. The program can predict the probability of landslides occurring in natural terrain and can estimate the zone of damage caused by a debris flow. It can also be used to design the location and size of countermeasures against the debris flow. The program is run using the ArcGIS Engine, which is one of the most well-known Geographic Information System (GIS) tools for developers. The quasi-dynamic wetness index and the infinite slope stability equation were applied to predict landslide probability as a type of slope safety factor. The calculated safety factor was compared with the required safety factor, and areas of high probable potential for landslides were then selected and represented on the digital map. The volume of debris flow was estimated using these areas of high probable potential for landslides and soil depth. The accumulated volume of debris flow can be calculated along the flow channel. To assess the accuracy of the program, it was applied to a real landslide site at Deoksan-ri, Inje-gun, Kangwon-Province, where four debris barriers have been installed in the watershed of the site. The results of soil tests and a field survey indicate that the program has great potential for estimating probable landslide areas and the trajectory of debris flows. Calculation of the capacity volume of existing debris barriers revealed that they had insufficient capacity to store the calculated amount of debris flow. Therefore, this program enables a rational estimation of the optimal location and size of debris barriers.

• Journal of the Korean Association of Geographic Information Studies
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• v.4 no.4
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• pp.61-71
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• 2001

In these days, surveying instruments are developing rapidly and the precision is improving continuously. The reappearance of three dimensional terrains of a great precision are possible and the calculation of the area or the volume has a high precision due to the development of the technique of the spatial information system using computer. But actually, in construction site they calculate two-dimensional area using the traditional method, plane table surveying, planimeter, and then get ground surface area through timing the slope correction factor. In this study, I show the defect and inefficiency of the calculation of the area by the traditional methods and survey the area with Electronic Distance Measuring equipment and GPS instrument. With these data, we made the three dimensional terrain model and calculated two-dimensional area and ground surface area. After that, I compared areas that calculated by algorithm method of irregular triangle and analysis of grid method with standardizing the area that calculated by the traditional method. Finally, I suggested more effective and precise method in calculating ground surface area.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.3
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• pp.113-122
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• 2007

The rapid growth of aerial survey and remote sensing technology has enabled the rapid acquisition of very large amounts of geographic data, which should be analyzed using real-time visualization technology. The level of detail(LOD) algorithm is one of the most important elements for realizing real-time visualization. We chose the triangulated irregular network (TIN) method to generate normalized digital elevation model(DEM) data. First, we generated TIN data using contour lines obtained from a two-dimensional(2D) digital map and created a 2D grid array fitting the size of the area. Then, we generated normalized DEM data by calculating the intersection points between the TIN data and the points on the 2D grid array. We used constrained Delaunay triangulation(CDT) and ray-triangle intersection algorithms to calculate the intersection points between the TIN data and the points on the 2D grid array in each step. In addition, we simulated a three-dimensional(3D) terrain model based on normalized DEM data with real-time visualization using a Microsoft Visual C++ 6.0 program in the DirectX API library and a quad-tree LOD algorithm.