• The Journal of Engineering Geology
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• v.33 no.2
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• pp.275-291
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• 2023

Global warming has made the polar regions more accessible, leading to increased demand for the construction of new resource-development plants in oil-rich permafrost regions. The selection of locations of resource-development plants in permafrost regions should consider the surface displacement resulting from thawing and freezing of the active layer of permafrost. However, few studies have considered surface displacement in the selection of optimal locations of resource-development plants in permafrost region. In this study, Analytic Hierarchy Process (AHP) analysis using a range of geospatial information variables was performed to select optimal locations for the construction of oil-sands development plants in the permafrost region of southern Athabasca, Alberta, Canada, including consideration of surface displacement. The surface displacement velocity was estimated by applying the Small BAseline Subset Interferometric Synthetic Aperture Radar technique to time-series Advanced Land Observing Satellite Phased Array L-band Synthetic Aperture Radar images acquired from February 2007 to March 2011. ERA5 reanalysis data were used to generate geospatial data for air temperature, surface temperature, and soil temperature averaged for the period 2000~2010. Geospatial data for roads and railways provided by Statistics Canada and land cover maps distributed by the North American Commission for Environmental Cooperation were also used in the AHP analysis. The suitability of sites analyzed using land cover, surface displacement, and road accessibility as the three most important geospatial factors was validated using the locations of oil-sand plants built since 2010. The sensitivity of surface displacement to the determination of location suitability was found to be very high. We confirm that surface displacement should be considered in the selection of optimal locations for the construction of new resource-development plants in permafrost regions.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.306-314
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• 2023

Stream sediments are an important component of water quality management because they are receptors of various pollutants such as heavy metals and organic matters emitted from upland sources and can be secondary pollution sources, adversely affecting water environment. To effectively manage the stream sediments, identification of primary sources of sediment contamination and source-associated control strategies will be required. We evaluated the performance of machine learning models in identifying primary sources of sediment contamination based on the physico-chemical properties of stream sediments. A total of 356 stream sediment data sets of 18 quality parameters including 10 heavy metal species(Cd, Cu, Pb, Ni, As, Zn, Cr, Hg, Li, and Al), 3 soil parameters(clay, silt, and sand fractions), and 5 water quality parameters(water content, loss on ignition, total organic carbon, total nitrogen, and total phosphorous) were collected near abandoned metal mines and industrial complexes across the four major river basins in Korea. Two machine learning algorithms, linear discriminant analysis (LDA) and support vector machine (SVM) classifiers were used to classify the sediments into four cases of different combinations of the sampling period and locations (i.e., mine in dry season, mine in wet season, industrial complex in dry season, and　industrial complex in wet season). Both models showed good performance in the classification, with SVM outperformed LDA; the accuracy values of LDA and SVM were 79.5% and 88.1%, respectively. An SVM ensemble model was used for multi-label classification of the multiple contamination sources inlcuding landuses in the upland areas within 1 km radius from the sampling sites. The results showed that the multi-label classifier was comparable performance with sinlgle-label SVM in classifying mines and industrial complexes, but was less accurate in classifying dominant land uses (50~60%). The poor performance of the multi-label SVM is likely due to the overfitting caused by small data sets compared to the complexity of the model. A larger data set might increase the performance of the machine learning models in identifying contamination sources.

• Korean Journal of Heritage: History & Science
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• v.42 no.3
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• pp.154-175
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• 2009

At the present state, studies on Gyeongbok palace are being done with history of architecture, records, and art. However, these studies have limits that they can only depend on existing buildings and record, which make it hard to research whole aspect of palaces. The foundation remains(Jeoksim) of Gyeongbok palace in the ground gives important clues that can fill the gaps of these studies. Thus I analysed jeoksim of Gyeongbok palace, assorted them by type, scale, material, and construction method. I examined jeoksim used by various types of building, and looked at changes by periods. Jeoksims are classified in 21 types. The foundation(jeoksim) varies according to types of buildings, building types and material of jeoksim also varies along the periods, and the fact proves certain peroid of time has its own jeoksim style in fashion. Jeoksims of Gyeongbok palace are divided into round-shape(I), rounded square-shape(II), rectangular-shape(III), square-shape(IV), and whole foundation of building(V) by the plane shape. They can be divided again into 21 types by construction techniques and materials used. During early Joseon(I), only three types of jeoksim; round-shape riprap jeoksim(1-1), II-1(rounded square-shape), II-2a(rounded square-shape riprap+roofingingtile brick), had been built, but as 19th century begun, all 21 types of jeoksim had built. In 19th century during Emperor Gojong, different types of jeoksim by periods were built, and especially different materials were used. During Gojong year 2(1865)~year 5(1868), in which Gyeongbok palace were rebuilt, 7 out of 10 types of jeoksim used piece of roofinging tile and brick mixture, in contrast, during Gojong year 10(1873)~13(1876), or 25(1888), 3 out of 5 types of jeoksim used sandy soil with mixture of plaster. Meanwhile palace buildings have different names by the class of owner and use such as Jeon, Dang, Hap, Gak, Jae, Heon, Nu, and Jeong, which were classified by types and buildings were built according to each level. With an analysis of jeoksim by its building types, I ascertained that jeoksim were built differently in accordance to building types(Jeon, Dang, Hap, Gak, Jae, Heon, Nu, and Jeong). By the limitation of present document, only some types of buildings such as Jeon, Dang, Gak, Bang were confirmed, as for Jeon and Gak, square-shape(IV) built with rectangular parallelepiped stone, and for Dang and Bang, rounded square-shape(IV) built with roofinginginging tile and riprap were commonly used. From the fact that other jeoksim with uncertain building names, were mostly built in early Joseon, we learn that round-shape riprap jeoksim(1-1) were commonly built. Therefore, the class of building was higher if the owner was in higher class, jeoksim is also considered to be built with the strongest and best material. And for Dang and Bang, rounded square-shape jeoksim were used, Dang has lots of II-2a (riprap + piece of roofing tile and brick rounded square-shape) type which mainly used riprap and piece of roofing tile and brick, but Bang has lots of II-2b (piece of roofing tile and brick+(riprap+piece of roofing tile and brick rounded square-shape), which paved piece of roofing tile and brick by 15~20cm above. These jeoksim by building types were confirmed to have changed its construction type by period. As for Jeon and Gak, they were built with round-shape riprap jeoksim(1-1) in early Joseon(14~15c), but in late Joseon(19c), various types of Jeoksim were built, especially square-shape(IV) were commonly built. For Dang, only changes in later Joseon were confirmed, jeoksim built in Gojong year 4(1867) mostly used mixture of riprap and piece of roofing tile and brick. In Gojong year 13(1876) or year 25(1888), unique type of plaster with sand and coal and soil layered jeoksim were built that are not found in any other building types. Through this study, I learned that various construction types of jeoksim and material were developed in later Joseon compare to early Joseon. This states that construction technique of building foundation of palace has upgraded. Above all, I learned jeoksim types are all different for various kinds of buildings. This tells us that when they constructed foundation of building, they used pre-calculated construction technique.