• International Journal of Highway Engineering
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• v.13 no.1
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• pp.139-148
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• 2011

Asphalt concrete overlay method is used by general maintenance and rehabilitation of construction for aged concrete pavement in Korea. However, in case of the AC overlay method to extend service life of the existing concrete pavements, various distresses of reflection crack, pothole and rutting are the typical problems of the asphalt overlay on existing concrete pavement since it has different physical characteristics between asphalt overlay and existing concrete pavement. To achieve this, application of concrete overlay method is required instead of AC overlay method. Concrete overlay method has advantages that can reduce maintenance cycle and costs since it has excellent bearing value for heavy vehicles and no rutting. However, technical problems of detour road construction, traffic control and other disadvantages happened by long curing time. Thus, in this study and experimental research were launched to evaluate the workability, durability and resistance against environmental loading of Very Rapid Hardening Acrylic Polymer Modified Concrete(VRH-APMC) for application of bonded concrete overlay method. Test results showed that the compressive and bond strength were exceed 21MPa and 1.4MPa of target strength after four hours for rapid traffic opening properties. And tests of resistance against environmental loading results showed that VRH-APMC secured excellent durability. Thus, it was known that VRH-APMC was suitable material for large scale bonded concrete overlay method, and it was possible to use maintenance and rehabilitation method which needs enough workability and rapid traffic opening.

• Korean Journal of Ecology and Environment
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• v.48 no.1
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• pp.68-76
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• 2015

There is no willow riparian vegetation in Jeju Island, Korea. Instead, a genetically-isolated population of Adina rubella is found in some parts of the riparian system. We describe its syntaxonomy and synecology. A total of 27 phytosociological relev$\acute{e}$s were collected, 11 relev$\acute{e}$s from 91 sites and 16 relev$\acute{e}$s from the previously published relevant materials. Data were analyzed by traditional Braun-Blanquet method and multivariate PCoA (Principal coordinates analysis). New syntaxa are distinguished, Adinion rubellae all. nov. and its type association Tripogono-Adinetum rubellae ass. nov. with two subassociations, typicum and rhododendretosum poukhanensae. Adino-Rhododendretum poukhanensae Itow et al. 1993 was discarded owing to mismatch of syntaxonomy and syngeography of Adina and Rhododendron phytocoena. The alliance Adinion is Jeju's regional and partly ombrotrophic vegetation occurring in pothole and rock crevice where are independent on ground-water table. We also suggest a revised alliance, Rhododendrion poukhanensae Lee 2004 ex. hoc loco in Korean peninsula, as a corresponding syntaxon to Adinion, which completely differs from Phragmito-Salicion. Finally we pointed out that Adina phytocoena requiring an absolutely monitoring has been threatened by river maintenance project of local government.

• Korean Journal of Construction Engineering and Management
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• v.15 no.4
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• pp.150-158
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• 2014

A bunch of asphalt roads have been damaged frequently in relation to the rapid climate change. To solve and prevent this type of problems, many nationalities in the world have performed various researches. In this regard, the objective of this study is to develop prediction model as to the number of potholes occurred in seoul. At the same time, we have utilized empirical and statistical approaches in order for us to identify factors which is affecting the actual occurrence. The predictive model was determinded by using BHS (Basic Harmony Search) algorithm. Prediction was based on the weather and traffic data as well as data occurrence data of porthole. To assess the influences which are PAR(Pitch Adjusting Rate) and HMCR(Harmony Memory Considering Rate), we determined suitability by changing the values. In the process of the determining a predictive model, the predictive model composed Training data (2011, 2012 and 2013yrs data). To determine the suitability of the model, we have utilized Testing Set (2009 and 2010 yrs data). The suitability of the basic prediction model has been from RMSE(Root Mean Squared Error), MAE(Mean Absolute Error) and Coefficient of determination.

• Journal of The Geomorphological Association of Korea
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• v.19 no.2
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• pp.31-49
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• 2012

Satae cheon, a tributary of the Suip cheon in Yanggu, Gangwon province, is an international river extended to North Korea. Most of drainage basin area of the river was the fierce battle field during the Korean War(1950-1953) and hard to access as it located between the MDL(Military Demarcation Line) and the CCZ(Civilian Control Zone: about 10km south from MDL). By the restriction of access to the sites, most of natural landscape have been well conserved except limited use for military activities. Even the landfoms in that area were not studied, except the government's heritage reports. Satae Cheon's channel follows the Imdang fault line(N-S) to Satae-ri and flow to west to the Dutayeon area. The river meanders along geological structure or weak line at the Dutayeon area. The meandering channel was shorten by the meander cut which linked the thalweg line of meander loop ant the meander neck. As a result of this cut, the river cliff formed by the Satae cheon became the part of newly formed channel bed and the S-forms are formed. After the channel route stabilized, channel incised the rock with large potholes and undulating walls were formed. The channel width changes from 1m to 10m with restriction of the undulating walls, so this part can be regarded as inner channel or inner gorge. From the point of planar forms it also can be slot-type canyon.

• Journal of The Geomorphological Association of Korea
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• v.19 no.3
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• pp.51-69
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• 2012

Physical strength of the rock is the most important factor of resistance to erosion and has been measured through various way. Bedrock microforms, like potholes and grooves, are the forms sculpted by the erosional processes of flow and the location and morphology are strongly affected by the differential erosion. It also assumed that the physical strength of the rock controls the erosion rate and mode of erosion. The schmidt hammer has been used to measure the rock strength in the field for the geomorphological research. To find the relationship between the rock strength and microforms, Schmidt hammer's R(rebound) were measured in the Baeksuktan, middle reach of Gilancheon, Cheongsong, Gyungsangbuk do. The overall values of rebound of the local sandstone showed over 65 in most cases, so it can be regarded as 'very strong'. It is found that the rebound values of the rock surface decreased towards current water level. It also, however, found that there was no systematic differences in rebound values among the topographically high and lows in the bedrock surface. There was no statistically significant difference in rebound values of the area with well developed microforms and others. The values of R from the exposed faces and inside of the microforms are similar. In the case of conglomerate, the part with the gravel showed higher values that the parts with sands. The rebound values are decreased near of(<1cm) the geological discontinuities(including joint and faults), so this line of weakness could be the point of initiation of active erosion to form microforms. However there is large variations in rebound values within this part. It also should be mentioned that topological relation between the strike of the geologic discontinuities and flow direction looks control the mode of erosional processes.

• Journal of Intelligence and Information Systems
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• v.29 no.3
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• pp.79-101
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• 2023

The current status of local road pavement management in Jeollabuk-do only relies on the accomplishments of the site construction company's pavement repair and is only managed through Microsoft Excel and word documents. Furthermore, the budget is irregular each year. Accordingly, a systematic maintenance plan for local roads is necessary. In this paper, data related to road damage and road environment were collected and processed to derive possible areas which could suffer from road damage. The effectiveness of the methodology was reviewed through the on-site inspection of the area. According to the Ministry of Land, Infrastructure and Transport, in 2018, the number of damages on general national roads were about 47,000. In 2019, it reached around 38,000. Furthermore, the number of lawsuits regarding the road damages were about 93 in 2018 and it increased to 119 in 2019. In the case of national roads, the number of damages decreased compared to 2018 due to pavement repairs. To measure the priorities in maintenance of local roads at Jeollabuk-do, data on maintenance history, local port hole occurrence site, overlapping business section, and emergency maintenance section were transformed into data. Eventually, it led to improvements in maintenance of local roads. Furthermore, spatial data were constructed using various current status data related to roads, and finally the data was processed into a new form that could be utilized in machine learning and predictions. Using the spatial data, areas requiring maintenance on pavement were predicted and the results were used to establish new budgets and policies on road management.

• Land and Housing Review
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• v.14 no.2
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• pp.125-135
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• 2023

Drones are used in various fields, including land survey, transportation, forestry/agriculture, marine, environment, disaster prevention, water resources, cultural assets, and construction, as their industrial importance and market size have increased. In this study, image data for deep learning was collected using a mavic3 drone capturing images at a shooting altitude was 20 m with ×7 magnification. Swin Transformer and UperNet were employed as the backbone and architecture of the deep learning model. About 800 sheets of labeled data were augmented to increase the amount of data. The learning process encompassed three rounds. The Cross-Entropy loss function was used in the first and second learning; the Tversky loss function was used in the third learning. In the future, when the crack detection model is advanced through convergence with the Internet of Things (IoT) through additional research, it will be possible to detect patching or potholes. In addition, it is expected that real-time detection tasks of drones can quickly secure the detection of pavement maintenance sections.