• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.4
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• pp.104-114
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• 2016

Potholes have caused diverse problems such as wheel damage and car accident. A pothole detection technology is the most important to provide efficient pothole maintenance. The previous pothole detections have been performed by manual reporting methods. Thus, the problems caused by potholes have not been solved previously. Recently, many pothole detection systems based on video cameras have been studied, which can be implemented at low costs. In this paper, we propose a new pothole detection algorithm based on saliency map information in order to improve our previously developed algorithm. Our previous algorithm shows wrong detection with complicated situations such as the potholes overlapping with shades and similar surface textures with normal road surfaces. To address the problems, the proposed algorithm extracts more accurate pothole regions using the saliency map information, which consists of candidate extraction and decision. The experimental results show that the proposed algorithm shows better performance than our previous algorithm.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.553-559
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• 2020

In order to prevent subsidence in urban areas, which is a major cause of damage to aging underground facilities, an integrated underground space map is being produced for systematic management of underground facilities. However, there is a problem of delaying the update time because an unupdated underground facility object is included in the process of updating the underground space integrated map. In this paper, we proposed a method to shorten the update time of the integrated map by selecting only the updated objects required for the update process of the underground space integrated map based on the central point of the underground facilities. Through the comparison of the centroid, the number of search targets is greatly reduced to shorten the search speed, and the distance of the actual location values between the two objects is calculated whether or not the objects are the same. The proposed method shows faster performance as the number of data increases, and the updated object can be reflected in the underground space integrated map about four times faster than the existing method.

• Economic and Environmental Geology
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• v.40 no.1 s.182
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• pp.87-101
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• 2007

A variety of informations obtained from satellite image, digital elevation relief map (DEM), borehole logging, televiewer, geophysical prospecting, etc were synthetically analyzed to investigate subsurface geological and structural characteristics and to evaluate geohazard pertinent to fault-damage in the Busan metropolitan city. It is revealed that the geology is composed of the Cretaceous andesitic$\sim$dacitic volcanics, gabbro, and granitoid and that at least three major faults including the Dongrae fault are developed in the study area. Based on characteristics of topography, fault-fractured zone, and isobath maps of the Quaternary sediments and weathered residuals of the basement, the Dongrae fault is decreased in its width and fracturing intensity of damaged zone from south toward north, and the fault is segmented around the area between the Seomyeon and Yangieong junctions. Meanwhile, we drew a geohazard sectional map using the five major parameters that significantly suggest damage intensity of basement by fault, i.e. distance from fault core, TCR, RQD, uniaxial rock strength, and seismic velocity of S wave. The map is evaluated as a suitable method to express the geological and structural characteristics and fault-damaged intensity of basement in the study area. It is, thus, concluded that the proposed method can contribute to complement and amplify the capability of the present evaluation system of rock mass.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.768-777
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• 2017

The efforts to improve river levee maintenance technologies have accelerated globally in a bid to deal with the flood damage resulting from the changes to the climate and flood events. This paper, in line with such tendency, proposes an evaluation system of a river levee safety map to maintain the river levee in an efficient manner. The concept of a river levee safety map is aimed at maximizing the maintenance efficiency for a manager to indicate the safety index, including the current river levee sliding, piping, and visual inspection on a GIS map. To develop such an evaluation system, a safety index covering the sliding, piping, and visual inspection are designated through the data and document examination and the rational guideline to classify each index into three grades, A, B, and C, is proposed. Based on the guideline proposed, the sliding and piping characteristics in terms of safety depending on the change to the flood water level duration time at the test section (Nam river) were evaluated by numerical analysis. As a result, both the protected landside and riverside satisfied the requirements for Grade A in terms of sliding, and when it comes to piping, the grade declined to C because the flood water level duration time increased at R2. As a planning study to propose a river levee safety map evaluation system, a further advanced study, standardization of the river levee data, and improvement of the existing system and laws are required.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.4
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• pp.31-46
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• 2021

In South Korea, there is a growing domestic need for a biotope map which contains ecological and environmental geographic information of a city. After the production of a Urban Ecological Maps(biotope map) by the Seoul metropolitan government in 2000, Natural Environment Conservation Act was revised in 2017 to make it mandatory for a local government to draw up its own urban ecological map. The aim of the present study was to find out ways to utilize an urban ecological map as a mean of communication between natural environment planning and urban planning sectors in a preliminary stage before introducing a big framework of 'environmental and ecological planning.' The northern area of Incheon metropolitan city was selected as the target area for this study. The major research content includes a comparative analysis of special-purpose zones, urban planning zones, restricted development zones, and conservation forests with focus on biotope types and Grades 1 of 'Biotope Type Assessment.' Farmland biotopes and forest biotopes within an area designated as an urban zone (residential, commercial and industrial zones) need to be redesignated as a zone which can conserve them. Especially considering a high possibility of damage to a large scale of natural green areas, these areas need to be readjusted immediately. If the entire area designated as an urban planning zone is to be developed, it is likely to cause serious damage to natural biotopes in the area (56.2%), including farmland biotope (30.4%), forest biotope (15.0%) and grassland biotope (10.8%), and thus, readjustment is needed. In case of a conservation forest, as it can possibly be damaged by the designation of special-purpose zones, it is necessary to match the designation of conservation forests or a special-purpose zones with their biotope types. In conclusion, we present a variety of thematic maps for utilization of an urban ecological map and propose a phase-specific environmental and ecological plan. Phase 1 is the establishment of a urban plan in consideration of ecological status; Phase 2 is the independent establishment of an environmental and ecological plan by an environment department; Phase 3 is an integrated management of ecological planning system and urban planning system.

• Journal of Forest and Environmental Science
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• v.40 no.1
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• pp.24-34
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• 2024

Fire, being primarily a natural phenomenon, is impossible to control, although it is feasible to map the forest fire risk zone, minimizing the frequency of fires. The spread of a fire starting in any stand in a forest can be predicted, given the burning conditions. The natural cover of the land and the safety of the population may be threatened by the spread of forest fires; thus, the prevention of fire damage requires early discovery. Satellite data and geographic information system (GIS) can be used effectively to combine different forest-fire-causing factors for mapping the forest fire risk zone. This study mainly focuses on mapping forest fire risk in the Madikhola watershed. The primary causes of forest fires appear to be human negligence, uncontrolled fire in nearby forests and agricultural regions, and fire for pastoral purposes which were used to evaluate and assign risk values to the mapping process. The majority of fires, according to MODIS events, occurred from December to April, with March recording the highest occurrences. The Risk Zonation Map, which was prepared using LULC, Forest Type, Slope, Aspect, Elevation, Road Proximity, and Proximity to Water Bodies, showed that a High Fire Risk Zone comprised 29% of the Total Watershed Area, followed by a Moderate Risk Zone, covering 37% of the total area. The derived map products are helpful to local forest managers to minimize fire risks within the forests and take proper responses when fires break out. This study further recommends including the fuel factor and other fire-contributing factors to derive a higher resolution of the fire risk map.

• Smart Structures and Systems
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• v.16 no.5
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• pp.873-889
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• 2015

In civil engineering, probabilistic seismic risk assessment is used to predict the economic damage to a lifeline system of possible future earthquakes. The results are used to plan mitigation measures and to strengthen the structures where necessary. Instead, after an earthquake public authorities need mathematical models that compute: the damage caused by the earthquake to the individual vulnerable components and links, and the global behavior of the lifeline system. In this study, a framework that was developed and used for prediction purpose is modified to assess the consequences of an earthquake in quasi real-time after such earthquake happened. This is possible because nowadays entire seismic regions are instrumented with tight networks of strong motion stations, which provide and broadcast accurate intensity measure maps of the event to the public within minutes. The framework uses the broadcasted map and calculates the damage to the lifeline system and its component in quasi real-time. The results give the authorities the most likely status of the system. This helps emergency personnel to deal with the damage and to prioritize visual inspections and repairs. A highway transportation network is used as a test bed but any lifeline system can be analyzed.

• Journal of Power System Engineering
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• v.18 no.5
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• pp.137-143
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• 2014

An investigation on lightning characteristics and damage to wind turbines was performed on Jeju and Gangwon regions. The lightning data from January 2010 to September 2013 detected by IMPACT ESP were collected and analyzed in detail. Hangyeong and Seongsan wind farms of Jeju province and Taebaek, Changjuk, Taegisan and Gangwon wind farms of Gangwon province were selected for this study. Lightning rates and lightning damage events at the six wind farms were compared with each other. Lightning maps for the two regions were drawn using lightning frequency data. As a result, lightning frequency of Gangwon region was higher than that of Jeju region, while lightning strength of Gangwon was weaker than that of Jeju. Lightning rates were assessed to be good for all of the six wind farms. No lightning damage to wind turbines occurred at the two wind farms of Jeju, while some lightning damage to wind turbines took place at the four wind farms of Gangwon.

• Structural Monitoring and Maintenance
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• v.3 no.3
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• pp.215-232
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• 2016

This paper presents a multi helical ultrasonic imaging approach for quantitative corrosion damage monitoring of cylindrical structures. The approach consists of two stages. First a multi helical ultrasonic imaging (MHUI) algorithm is used to provide qualitative images of the structure of interest. Then, an optimization problem is solved in order to obtain quantitative damage information, such as thickness map. Experimental tests are carried out on a steel pipe instrumented with six piezoelectric transducers to validate the proposed approach. Three thickness recesses are considered to simulate corrosion damage. The results show the efficiency of the proposed approach for quantifying corrosion location, area and remnant thickness.

• Journal of the Korean Professional Engineers Association
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• v.45 no.1
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• pp.45-48
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• 2012

The 2011 Japan Tsunami caused tremendous damage to coastal areas. Because of their drastic propagation speed and large run-up height, nearshore tsunami can cause catastrophic damages on coastal communities within a short time. It is necessary to establish the tsunami hazard mitigation to reduce human injury housing damage. The construction of Tsunami warning system and production of hazard map are needed for minimizing damage by tsunami.