• Journal of Korean Classical Literature and Education
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• no.32
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• pp.5-27
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• 2016

This study shows the points of interest and the meanings contained within Hyangga which are derived from three literary characteristics: easy-to-understand structure of dialectic thinking, old-fashioned and universal lyric, and the sense of a place from the past that it reveals. Hyangga is a literary genre that is structured on dialectic thinking in its form and contents. The construction of meaning in these poems happens three stages, which is explicit in four-line and eight line Hyangga as well as in ten-line Hyangga. Therefore, to enjoy Hyangga, it makes more sense to understand the structure of the thoughts contained in Hyangga. A deeper understanding and enjoyment of the thoughts contained in Hyangga can be gained by thinking dialectically. The poems of Hyangga that have survived to present day have peculiar and rich lyrics. The emotions and thoughts contained in Hyangga are a combination of the universal human being and historically peculiar ones. The literary interests of Hyangga come from its universality and individuality, and the concreteness and reality of emotions expressed in its poems. Its beautifully and aesthetically described emotions resonate deep within us. The poems of Hyangga reveal features relating to spaces. We are able to get a sense of places from the past by reading their description in these poems. The places mentioned in Hyangga bring about a connection between our past and our present because they describe the same place but in a different period. Hyangga is a literary genre depicting the emotions and thoughts derived from places that belong to our people's territories. Therefore, the sense of place that Hyangga awakens in us reveals how we exist in the flow of our history. To sum up, the point of interest and meaning contained within Hyangga reveal the structure of dialectic thinking, the lyrics of those days, and the feeling of a sense of place. If these boundaries can be extended, there will be a wider scope for enjoying Hyangga.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.3
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• pp.1-20
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• 2023

The present study has monitored the changes in the biodiversity of Dunchon-Dong ecological and landscape conservation area after the restoration of the wetland, identified and analyzed the threats to the ecosystem, and presented a management plan accordingly. In this area which was forests and rice paddies in the past, apartment reconstruction is currently underway, with some hinterland forests and wetlands remaining. When we look into the change in the floras, the total number of species was 193 in 2000 before the restoration, it decreased from 2004 to 2006, and as of 2019, it was 149, showing an increasing trend. The result of comparing the species that emerged before and after the restoration showed an increase in Cyperaceae herbs such as Carex maximowiczii and Carex dispalata growing in wetland areas within forests and Schoenoplectiella juncoides and Schoenoplectus tabernaemontani growing in areas within wetlands where shallow water is maintained. As a result of analyzing the change in the area ratio of each type of extant vegetation, the wetland native herbs formed the power at the highest ratio after the restoration. The change in the power of the wetland native herbs was on an increasing trend until 2007, after which it decreased much in 2010 and then gradually increased, showing values of 26.6% in 2000, 44.6% in 2002, 49.0% in 2005, 53.3% in 2007, 28.7% in 2010, and 37.3% in 2019. The cause of the decrease in 2010 was judged to be due to the vegetation management conducted to secure open water and remove organic matter in freshwater reservoirs. The amphibia which emerged from 2000 to 2019 was a total of 9 species including Hynobius leeshii, Bufo gargarizans, Kaloula borealis, and Rana uenoi. As a result of the changes in the emerging wild birds, the species diversity index before the restoration was 0.9922 in 2000, and the species diversity index after the restoration gradually increased to 1.2449 in 2005, 1.2467 in 2010, and 2.2631 in 2019. The amphibia and wild birds inhibiting in the Dunchon-Dong forest and wetland were judged to have increased through continuous wetland maintenance such as naturalized plant removal management, native plant maintenance, and open water securing management. For the ecosystem preservation management of the Dunchon-Dong ecological and landscape conservation area, it was suggested to minimize the impact of the Dunchon-Dong reconstruction project, reorganize the indiscriminate access roads adjacent to the wetland, and reorganize the main entrance to the wetland. For ecosystem restoration management, systematic restoration and ecological buffer planting were suggested to be carried out at the time of construction fence demolition.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.2
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• pp.81-87
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• 2006

Purpose: Few researches have been peformed on the dose distribution of the moving organ for radiotherapy so far. In order to simulate the organ motion caused by respiratory function, multipurpose phantom and moving device was used and dosimetric measurements for dose distribution of the moving organs were conducted in this study. The purpose of our study was to evaluate how dose distributions are changed due to respiratory motion. Materials and Methods: A multipurpose phantom and a moving device were developed for the measurement of the dose distribution of the moving organ due to respiratory function. Acryl chosen design of the phantom was considered the most obvious choice for phantom material. For construction of the phantom, we used acryl and cork with density of $1.14g/cm^3,\;0.32g/cm^3$ respectively. Acryl and cork slab in the phantom were used to simulate the normal organ and lung respectively. The moving phantom system was composed of moving device, moving control system, and acryl and cork phantom. Gafchromic film and EDR2 film were used to measure dose ditrbutions. The moving device system may be driven by two directional step motors and able to perform 2 dimensional movements (x, z axis), but only 1 dimensional movement(z axis) was used for this study. Results: Larger penumbra was shown in the cork phantom than in the acryl phantom. The dose profile and isodose curve of Gafchromic EBT film were not uniform since the film has small optical density responding to the dose. As the organ motion was increased, the blurrings in penumbra, flatness, and symmetry were increased. Most of measurements of dose distrbutions, Gafchromic EBT film has poor flatness and symmetry than EDR2 film, but both penumbra distributions were more or less comparable. Conclusion: The Gafchromic EBT film is more useful as it does not need development and more radiation dose could be exposed than EDR2 film without losing film characteristics. But as response of the optical density of Gafchromic EBT film to dose is low, beam profiles have more fluctuation at Gafchromic EBT. If the multipurpose phantom and moving device are used for treatment Q.A, and its corrections are made, treatment quality should be improved for the moving organs.

• Korean Journal of Heritage: History & Science
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• v.52 no.2
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• pp.62-79
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• 2019

This study examined the background of Gyeongju Seochulji Pond (world heritage, historic site No. 138), a historic pond in Sam-guk-yu-sa (三國遺事), and its landscaping period when it served as the garden of the Pungcheon Lim clan (豊川 任氏) in the middle of the Joseon dynasty. For this study, a literature review of poetry, prose, and a personal anthology, and a field survey were conducted. Changes in the landscape were analyzed by comparing the landscape appearing in the literature of the Joseon period with past photographs. The results were as follows: First, even though the function and landscape at that time cannot be guessed as the objective ground from Silla to the early part of the Joseon dynasty is insufficient, it has been managed as a Byeolseo (別墅) garden as Pungcheon Lim's family resided in the area of Eastern-Namsan Mountain during the Joseon dynasty. At that time, Seochulji Pond was recognized as a historic place. It functioned as the garden of Pungcheon Lim's family as Lim Jeok (任勣, 1612~1672) built the Yiyodang pavilion (二樂堂). Second, in the literature, the Yiyodang pavilion has been called Gaekdang (客堂), Jeongsa (精舍), Byeolgak (別閣) and Byeolseo, etc. It can be seen as Nu and Jeong (樓亭), utilized for various uses. Because of this, the name Bingheoru Pavilion (憑虛樓) has mostly been in common use. Third, Seochulji Pond was positioned where the scenery is beautiful, with Gyeongju Mt. Namsan (Mt. Geumo) in the background and with a wide field and the Namcheon River flowing in the front. This was typical of Byeolseo gardens of the Joseon dynasty, combining human environments with natural environments. Fourth, the relationship with the Byeolseo garden disappeared as the head of Pungcheon Lim's family added a temple, lotus flowers, pine trees, and a bamboo forest as described in the old poetry and prose. Currently, the landscape does not appear to be significantly different from that as development has not occurred in the area of Seochulji Pond. Also, crape myrtle (Lagerstroemia indica), which now symbolizes the Seochulji Pond, was not identified in the old poetry or past photographs and is not old enough to confirm whether it was prominent at the time. Through this study, it is necessary to reconsider the spatial meanings of the gardens of the Joseon dynasty period and not to highlight the area of Seochulji Pond as a place in the legend. This is a cultural asset in the area of Eastern-Namsan Mountain and has an important meaning in terms of garden history.

• Korean Journal of Heritage: History & Science
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• v.56 no.1
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• pp.226-256
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• 2023

Gyeongju has been the capital of Silla Kingdom for about 1,000 years, and many cultural heritages of the Silla period, such as the Wolseong Palace Site, Daereungwon Ancient Tomb Complex and Donggung Palace and Wolji Pond, are located in the city. Due to these characteristics, the process of heritagization has been carried out in Gyeongju from the Japanese colonial era to after liberation. Heritagization means selecting things from the past due to the needs of the present and making them heritages. In the case of South Korea, national government-led heritagization was achieved during the Japanese colonial period, and after liberation because of the restoration of national culture and the construction of a national identity. Gyeongju is a representative example. On the other hand, Gyeongju's heritagization process was carried out with little consideration of the local community, and thus the local community and Gyeongju's heritage have been distancing. In 2002, Gyeongju's heritage sites were nominated as World Heritage Sites. With the nomination, the perception of the role of local communities in heritage has been changed, and institutional mechanisms to promote the participation of local communities have been continuously reorganized. However, Gyeongju's heritagization process, which was thoroughly conducted through the central government and expert groups, was the reason why Gyeongju residents actually thought Gyeongju's heritage and the locality of Gyeongju were formed through the central government and expert groups. This has been the result of Gyeongju residents' passive participation in heritagization or heritage management to date. This study analyzed the heritagization process of Gyeongju through literature research and conducted an interview survey of residents who have lived in Gyeongju for a long time to understand the impact of the institutional heritagization process on residents and the relationship with heritage. Based on the analysis results, it was suggested that local residents and communities could take the initiative in managing the heritage of Gyeongju.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.815-826
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• 1994

Skew bridges are found frequently in new bridge construction due to geographical conditions when new constructing bridges are put across the existing highways, railroads or rivers. This study is to investigate the static behaviors of the steel deck plates of skew bridges which are increasingly used in bridges due to outstanding quality of structural steels, development of welding techniques, in order to reduce dead loads and period of constructions. The static behaviours of steel deck plates are analyzed using general purpose FE code SAP90 by modeling the skewed deck plates with rigorous finite elements, as the skew angles vary. The results of finite element analysis for the behaviors of steel deck plates and concrete slabs in acute, obtuse corners and center of decks are compared and discussed as the skew angles vary from $90^{\circ}$ to $30^{\circ}$. Two types of decks are treated, as isotropic plates and orthotropic plates, respectively. From the results of finite element analysis, it is found that more moments, reactions, and deflections occur at the obtuse corners than at the center of skewed decks regardless of isotropy or orthotropy. Especially, in case of the skewed deck plates with skew angles less than 45 degrees, significantly large discrepancies for the values of those internal forces are shown between the skewed and right deck plates. This study estimates the characteristics of deck behaviors according to skew angles, and proposes limitations of skew angles and the ciritical regions of decks.

• Journal of Korean Society of Forest Science
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• v.81 no.4
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• pp.363-371
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• 1992

This study was aimed at developing a computer model to determine rational road networks in mountainous forests. The computer model is composed of two major subroutines for digital terrain analyses and route selection. The digital terrain model(DTM) provides various information on topographic and vegetative characteristics of forest stands. The DTM also evaluates the effectiveness of road construction based on slope gradients. Using the results of digital terrain analyses, the route selection subroutine, heuristically, determines the optimal road layout satisfying the predefined road densities. The route selection subroutine uses the area-partitioning method in order to fully of roads. This method leads to unbiased road layouts in forest areas. The size of the unit partitiones area can be calculated as a function of the predefined road density. In addition, the user-defined road density of the area-partitioning method provides flexibility in applying the model to real situations. The rational road network can be easily achived for varying road densities, which would be an essential element for network design of forest roads. The optimality conditions are evaluated in conjuction with longitudinal gradients, investment efficiency earthwork quantity or the mixed criteria of these three. The performance of the model was measured and, then, compared with those of conventional ones in terns of average skidding distance, accessibility of stands, development index and circulated road network index. The results of the performance analysis indicate that selection of roading routes for network design using the digital terrain analysis and the area-partitioning method improves performance of the network design medel.

• Korean Journal of Remote Sensing
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• v.38 no.2
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• pp.139-151
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• 2022

SAGD (Steam-Assisted Gravity Drainage) method is widely used for oil recovery in oil sands regions. The SAGD operation causes surface displacement, which can affect the stability of oil recovery plants and trigger various geological disasters. Therefore, it isimportant to monitor the surface displacement due to SAGD in the oil sands region. In this study, the surface displacement due to SAGD operations of the Athabasca oil sands region in Alberta, Canada, was observed by applying Permanent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR) technique to the Sentinel-1 time series SAR data acquired from 2016 to 2021. We also investigated the construction and expansion of SAGD facilitiesfrom Landsat-7/8 time seriesimages, from which the characteristics of the surface displacement according to the oil production activity of SAGD were analyzed. Uplift rates of 0.3-2.5 cm/yr in the direction of line of sight were observed over the SAGDs and their vicinity, whereas subsidence rates of -0.3--0.6 cm/yr were observed in areas more than several kilometers away from the SAGDs and not affected by oil recovery activities. Through the analysis of Landsat-7/8 images, we could confirm that the SAGDs operating after 2012 and showing high oil production activity caused uplift rates greater than 1.6 cm/yr due to the subsurface steam injection. Meanwhile, very small uplift rates of several mm per year occurred over SAGDs which have been operated for a longer period of time and show relatively low oil production activity. This was probably due to the compression of reservoir sandstone due to continuous oil recovery. The subsidence observed in areas except for the SAGDs and their vicinity estimated to be a gradual land subsidence caused by melting of the permafrost. Considering the subsidence, it was expected that the uplift due to SAGD operation would be greater than that observed by the PSInSAR. The results of this study confirm that the PSInSAR can be used as an effective means for evaluating productivity and stability of SAGD in the extreme cold regions.

• Economic and Environmental Geology
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• v.57 no.4
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• pp.397-416
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• 2024

This study assessed the hydrogeological properties of the deep geological environment to develop safety criteria for the natural barriers used in the deep geological disposal of high-level radioactive waste in Korea. The assessment focused on the distribution and trends of hydraulic conductivity and permeability properties appropriate for the domestic geological environment, using various in-situ hydraulic test data collected for groundwater development and management. To develop a depth-hydrogeological property relationship model suitable for domestic conditions, the study reviewed various international research examples and applied a representative model that explains the trends of hydraulic conductivity and permeability with depth. The development of the model suitable for Korea involved applying ensemble regression analysis to account for the uncertainty of various factors in the collected data. The results confirmed that existing international depth-hydrogeological property relationship models adequately describe the characteristics of the domestic geological environment. Considering the preferred hydrogeological criteria suggested by countries like Sweden, Germany, and Canada, there is a high likelihood that a suitable geological environment exists in Korea. Additionally, the application of hydrogeological criteria indicative of low-permeability environments showed that suitable conditions for disposal construction increase at depths greater than 300 m, where the influence of fractures on groundwater flow might be minimal at depths exceeding 500 m. This research can serve as foundational information for establishing hydrogeological safety standards for natural barriers in Korea according to international regulatory guidelines.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.374-383
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• 2010

Microwave radar can penetrate cloud cover regardless of weather conditions and can be used day and night. Especially a ground-based polarimetric scatterometer has advantages of monitoring crop conditions continuously with full polarization and different frequencies. Kim et al. (2009) have measured backscattering coefficients of paddy rice using L-, C-, X-band scatterometer system with full polarization and various angles during the rice growth period and have revealed the necessity of near-continuous automatic measurement to eliminate the difficulties, inaccuracy and sparseness of data acquisitions arising from manual operation of the system. In this study, we constructed an X-band automatic scatterometer system, analyzed scattering characteristics of paddy rice from X-band scatterometer data and estimated rice growth parameter using backscattering coefficients in X-band. The system was installed inside a shelter in an experimental paddy field at the National Academy of Agricultural Science (NAAS) before rice transplanting. The scatterometer system consists of X-band antennas, HP8720D vector network analyzer, RF cables and personal computer that controls frequency, polarization and data storage. This system using automatically measures fully-polarimetric backscattering coefficients of rice crop every 10 minutes. The backscattering coefficients were calculated from the measured data at a fixed incidence angle of $45^{\circ}$ and with full polarization (HH, VV, HV, VH) by applying the radar equation and compared with rice growth data such as plant height, stem number, fresh dry weight and Leaf Area Index (LAI) that were collected at the same time of each rice growth parameter. We examined the temporal behaviour of the backscattering coefficients of the rice crop at X-band during rice growth period. The HH-, VV-polarization backscattering coefficients steadily increased toward panicle initiation stage, thereafter decreased and again increased in early-September. We analyzed the relationships between backscattering coefficients in X-band and plant parameters and predicted the rice growth parameters using backscattering coefficients. It was confirmed that X-band is sensitive to grain maturity at near harvesting season.