• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.22 no.6
• /
• pp.1-14
• /
• 2019

Carbon storage is one of the regulating ecosystem services provided by urban street trees. It is important that evaluating the economic value of ecosystem services accurately. The carbon storage of street trees was calculated by measuring the morphological parameter on the field. As the method is labor-intensive and time-consuming for the macro-scale research, remote sensing has been more widely used. The airborne Light Detection And Ranging (LiDAR) is used in obtaining the point clouds data of a densely planted area and extracting individual trees for the carbon storage estimation. However, the LiDAR has limitations such as high cost and complicated operations. In addition, trees change over time they need to be frequently. Therefore, Structure from Motion (SfM) photogrammetry with unmanned Aerial Vehicle (UAV) is a more suitable method for obtaining point clouds data. In this paper, a UAV loaded with a digital camera was employed to take oblique aerial images for generating point cloud of street trees. We extracted the diameter of breast height (DBH) from generated point cloud data to calculate the carbon storage. We compared DBH calculated from UAV data and measured data from the field in the selected area. The calculated DBH was used to estimate the carbon storage of street trees in the study area using a regression model. The results demonstrate the feasibility and effectiveness of applying UAV imagery and SfM technique to the carbon storage estimation of street trees. The technique can contribute to efficiently building inventories of the carbon storage of street trees in urban areas.

• Journal of Environmental Science International
• /
• v.29 no.12
• /
• pp.1249-1260
• /
• 2020

Non-point source pollutants have characteristics the render them difficult to manage owing to the uncertainty of flow paths. As agricultural non-point sources account for more than 57% of non-point source pollutants, the necessity for management is increasing. This study examines the possibility of utilizing land cover maps to suggest a more appropriate method of setting management priority for agricultural non-point sources in the Daecheong Lake area and draws implications by comparing the results derived using the cadastral map, as mentioned in the TMDL Basic Policy. To define the prioritized areas for management, the pollution load was calculated for each subbasin using the formula from the TMDL technical guidelines. As a result, the difference in the average pollution load between the land cover map and cadastral map ranged from 11.6% to 21% among the subbasins. In almost all subbasins, there were differences in the ranking of management priorities depending on the land information that was used. In addition, it was found that it was reasonable to use the level 3 land cover map to calculate the load generated by the land system for examining the implementation goals and methods of each data and comparing them with satellite images.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1991.04a
• /
• pp.69-74
• /
• 1991

This paper reviewed various methods of evaluating the toughness of fiber reinforced concrete materials by means of toughness indices and discussed the use of various multiples of first-crack deflection or first-crack secant compliance to define toughness indices. And a new method what is called effective toughness used to evaluate the toughness of steel fiber reinforced concrete. The proposed method determinded from the area below the load-deflection curve until deflection at the loading point becoms 1/150 of the span devided by the ligament area.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.23 no.4
• /
• pp.16-41
• /
• 2020

Geospatial input setting to represent the reality of spatial distribution or quantitative property within model has become a major interest in earth system simulation. Many studies showed the variation of grid resolution could lead to drastic changes of spatial model results because of insufficient surface property estimations. Hence, in this paper, the authors proposed Monte Carlo Integration (MCI) to apply spatial probability (SP) in a spatial-sampling framework using a three-dimensional point cloud (3DPC) to keep the optimized spatial distribution and area/volume property of buildings in urban area. Three different decision rule based building identification results were compared : SP threshold, cell size, and 3DPC density. Results shows the identified building area property tend to increase according to the spatial sampling grid area enlargement. Hence, areal building property manipulation in the sampling frameworks by using decision rules is strongly recommended to increase reliability of geospatial modeling and analysis results. Proposed method will support the modeling needs to keep quantitative building properties in both finer and coarser grids.

• Proceedings of the KIEE Conference
• /
• 1997.11a
• /
• pp.257-260
• /
• 1997

This paper designs the optimal PID controller for load frequency control on 2-area power system. Genetic algorithm is utilized to optimize parameters of PID controller which is applied to power system. Using two-point crossover, uniform crossover and one-point crossover, Search performance of genetic algorithm with each crossover method is considered. In case of load variation in 1-area, the dynamic characteristic of power system is considered. The simulation results show that the proposed PID controller is better control performance than PID controller using Ziegler-Nichols method.

• Journal of Institute of Control, Robotics and Systems
• /
• v.18 no.8
• /
• pp.794-799
• /
• 2012

The international standard, ISO-11783, was designed for the communication within an agriculture machinery. Even if it is based on the CAN (Control Area Network) protocol, its extended features which include point-to-point communication and large data transmission support show different network performance from the standard CAN. This paper proposes a dynamic priority allocation method to improve the real-time performance of ISO-11783. Computer simulation shows reduction of the deadline-missed cases and community latency via proposed algorithm.

• Journal of KIISE:Information Networking
• /
• v.37 no.6
• /
• pp.431-443
• /
• 2010

In this paper, we propose a range-free localization method that can improve the estimation accuracy of Approximate Point in Triangle(APIT), which is the representative localization method for low cost wireless sensor networks. Specifically, we propose extended-APIT(e-APIT) method, which minimizes the error in deciding whether an object is in an area formed by three beacons. We also propose a way to improve the localization by narrowing down the potential localization area using the signals from neighboring beacons. According to the simulation performed, the proposed e-APIT method demonstrated noticeable accuracy improvement over the conventional APIT method.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.38 no.1
• /
• pp.35-41
• /
• 2020

3D laser scanners are an effective way to quickly acquire a large amount of data about an object. Recently, it is used in various fields such as surveying, displacement measurement, 3D data generation of objects, construction of indoor spatial information, and BIM(Building Information Model). In order to utilize the point cloud data acquired through the 3D laser scanner, it is necessary to make the data acquired from many stations through a matching process into one data with a unified coordinate system. However, analytical researches on the accuracy of point cloud data according to the registration method are insufficient. In this study, we tried to analyze the accuracy of registration method of point cloud data acquired through 3D laser scanner. The point cloud data of the study area was acquired by 3D laser scanner, the point cloud data was registered by the ICP(Iterative Closest Point) method and the shape registration method through the data processing, and the accuracy was analyzed by comparing with the total station survey results. As a result of the accuracy evaluation, the ICP and the shape registration method showed 0.002m~0.005m and 0.002m~0.009m difference with the total station performance, respectively, and each registration method showed a deviation of less than 0.01m. Each registration method showed less than 0.01m of variation in the experimental results, which satisfies the 1: 1,000 digital accuracy and it is suggested that the registration of point cloud data using ICP and shape matching can be utilized for constructing spatial information. In the future, matching of point cloud data by shape registration method will contribute to productivity improvement by reducing target installation in the process of building spatial information using 3D laser scanner.

• International Journal of Contents
• /
• v.11 no.3
• /
• pp.7-13
• /
• 2015

One of the biggest problems of skeletonization is the occurrence of distortions at the junction point of the final binary image. At the junction area, a single point usually becomes a small stroke, and the corresponding trajectory task, as well as the OCR, consequently becomes more complicated. We therefore propose an adaptive post-processing method that uses an adaptive threshold technique to correct the distortions. Our proposed method transforms the distorted segments into a single point so that they are as similar to the original image as possible, and this improves the static handwriting images after the skeletonization process. Further, we attained promising results regarding the usage of the enhanced skeletonized images in other applications, thereby proving the expediency and efficiency of the proposed method.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.49 no.3
• /
• pp.197-204
• /
• 2021

If a failure or an abnormal maneuver occurs during the flight test of a missile, the missile is deliberately self-destructed so as not to continue the flight. At this time, debris are produced and it is important to estimate the impact area in real-time whether it is out of the safety area. In this paper, we propose a method to estimate the debris dispersion area and falling time in real-time using a Fully-Connected Neural Network (FCNN). We applied the Unscented Transform (UT) to generate a large amount of training data. UT parameters were selected by comparing with Monte-Carlo (MC) simulation to secure reliability. Also, we analyzed the performance of the proposed method by comparing the estimation result of MC.