• Fire Science and Engineering
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• v.31 no.5
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• pp.53-62
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• 2017

Electric power which is the energy source of economy and industries requires long distance transportation due to regional difference between its production and consumption, and it is supplied through the multi-loop transmission and distribution system. Prior to its actual use, electric power flows through several transformations by voltage transformers in substations depending on the characteristics of each usage, and a transformer has the structure consisting of the main body, winding wire, insulating oil and bushings. A transformer fire that breaks out in substations entails the primary damage that interrupts the power supply to houses and commercial facilities and causes various safety accidents as well as the secondary economic losses. It is considered that causes of such fire include the leak of insulating oil resulting from the destruction of bottom part of bushings, and the chain reaction of fire due to insulating oil that reaches its ignition point within 1 second. The smoke detector and automatic fire extinguishing system are established in order to minimize fire damage, but a difficulty in securing golden time for extinguishing fire due to delay in the operation of detector and release of gas from the extinguishing system has become a problem. Accordingly, this study was carried out according to needs of active mechanism to prevent the spread of fire and block the leak of insulating oil, in accordance with the importance of securing golden time in extinguishing a fire in its early stage. A bushings fireproof structure was developed by applying the high temperature shape retention materials, which are expanded by flame, and mechanical flame cutoff devices. The bushings fireproof structure was installed on the transformer model produced by applying the actual standards of bushings and flange, and the full scale fire test was carried out. It was confirmed that the bushings fireproof structure operated at accurate position and height within 3 seconds from the flame initiation. It is considered that it could block the spread of flame effectively in the event of actual transformer fire.

• Journal of the Institute of Convergence Signal Processing
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• v.16 no.4
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• pp.149-155
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• 2015

Tooth implant is located in oral cavity and affects neck, skull base, and facail image. These magnetic inhomogeneities are usually frequency encoding direction which cause artifacts due to change of signal strength and geometric distortion. First, to evaluate signal to noise ratio (SNR) of magnetic resonance image caused by tooth implant this study uses meat phantom which is similar to human body and is consisted with fat, muscle, and water to measure signal to noise ratio. Second, signal to noise ratio by using custom-made fixed phantom is measured, and then signal to noise ratio size of different tooth implant types is compared and analyzed. The measured signal to noise ratio values of Brushite, HSA, Metal, and RBM for meat phantom were 2.76, 2.22, 1.88, and 1.57 on T1 SE, 1.88, 1.78, 1.65, and 1.79 on T2 FLAIR, 2.28, 2.25, 2.88, and 2.05 on T2 FSE, and 2.74, 1.94, 1.67, and 1.48 on T2 GRE. The measured signal to noise ratio values of Brushite, HSA, Metal, and RBM for fixed water phantom were 1.2, 1.06, 1.12, and 1.22 on DWI, 1.93, 1.87, 1.93, and 2.06 T1 SE, 1.83, 1.76, 1.82, and 1.92 on T2 FLAIR, 1.85, 1.79, 7.86, and 1.97 on T2 FSE, and 1.97, 1.93, 1.99, and 2.06 on T2 GRE. By considering through the results, patients and dentists need to consider some impacts from testing many aspects although their main purpose of having tooth implants is a dental restoration. Moreover, depending on the tooth implant characteristics of individual patients this study results can be used as baseline data when choosing test protocol.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.30 no.3
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• pp.42-56
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• 2012

This study was carried out to investigate the construction characteristics and the landscaping design skill for Wiyiam at Ongnyucheon(玉流川) in the rear garden of Changdeok Palace focusing on constructing technique, space composition and transformational process of the site. The results of this study were summarized as follows; First, Wiyiam of Ongnyucheon was constructed as garden ornament which was modified the huge bedrock into the shape of the mountain. The waterfall of Wiyiam was originally made of torrent which water flowed into the bottom, but it was reconstructed to take the effect of Inak(離落: the method to drop water from high place) by carving rock into square shape at the era of King Gojong(高宗). Second, main characteristics of Wiyiam appeared in Donggwoldo was the hill built up with a square pond and ground at the back of Wiyiam and the profound scenery of mountains and stream from the view of Wiyiam. Also, pavilions such as Soyojeong(逍遙亭), Cheongujeong and Taegeukjeong(太極亭) built in Ongnyucheon seemed to be constructed as the spots to appreciate the view and waterfall sound of Wiyiam. Also the spots were not bounded by the function of creating special water systems such as Cheongujeong pond and Taegeukjeong pond and showed the outstanding landscape design skill to make people feel unusual interest from each spot. On the other hand, this study considered that the evening scenery of Wiyiam, beautiful sound of falling water, unusual water system with beautiful plant materials were landscaped for the function of the psychological peace and stability to the appreciators. Lastly, the extreme change of space composition in Ongnyucheon was assumed as a strategy to improve the existing poor drain environment by confirming that the mountain stream and wall of Soyojeong were removed and drainage in both side of Soyojeong was installed in the 21th year of King Gojong's reign(1884).

• Korean Journal of Remote Sensing
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• v.12 no.2
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• pp.139-154
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• 1996

In order to evaluate the sensor`s look direction bias in the Landsat TM image and to estimate trends of primary geological lineaments, we have attempted to systematically compare lineaments in TM image, relief shadowed DEM's, and actual lineaments of geologic and topographic map through the Hough transform technique. Hough transform is known to be very effective to estimate the trend of geological lineaments, and help us to obtain the true trends of lineaments. It is often necessary to compensate the preferential enhancements of terrain lineaments in a TM image occurred by to look direction bias, and that can be achieved by utilizing an auxiliary data. In this study, we have successfully adopted the relief shadowed DEM in which the illuminating azimuth angle is perpendicular to look direction of a TM image for assessing true trends of geological lineaments. The results also show that the sum of four relief shadowed DEM's directional components can possibly be used as an alternative. In Euiseong-gun area where Sindong Group and Mayans Group are mainly distributed, geological lineaments trending $N5^{\circ}$~$10^{\circ}$W are dominant, while those of $N55^{\circ}$~$65^{\circ}$ W are major trends in Cheongsong-gun area where Hayang Group, Yucheon Group and Bulguksa Granite are distributed. Using relief shadowed DEM as an auxiliary data, we found the $N55^{\circ}$~$65^{\circ}$ W lineaments which are not cleanly observed in TM image over Euiseong-gun area. Compared with the trend of Gumchon and Gaum strike-slip faults, these lineaments are considered to be an extension of the faults. Therefore these strike-slip faults possibly extend up to Sindong Group in the northwest parts in the study area.

• Journal of The Geomorphological Association of Korea
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• v.15 no.2
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• pp.67-83
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• 2008

To find out the process of hillslope denudation since the Last Glacial Maximum in Asan area, we conducted the stratiform interpretation and carbon age measurements with the collected samples through trenching in the valley bottom of 'Agol' located in the lower stream of Magok stream. The results are as follows. 11 inorganic and 8 organic matter layers were confirmed at the point of trench MG1 in the subject area, 7 inorganic and 3 organic at the point of trench MG2, and 5 inorganic and 3 organic at the point of trench MG3, respectively. The frequency of hillslope denudation, hillslope mass movement, which had occurred in the unstable environment of back hillslope at the point of MG 1, was 11 times (8 times before about 2,900yrBP, twice in between about 2,900~1,900yrBP, and once after about 1,900yrBP) as a whole. The frequency of moor which had formed in the comparatively stable environment of back hillslope was 9 times (5 times before about 3,000yrBP, twice in between 3,000~2,800yrBP, and once in between 2,200~1,900yrBP) at minimum. The frequency of back hillslope denudation at the point of MG2 was totally 7 times (4 times before about 1,900yrBP and 3 times after about 1,900yrBP) and the moor formations were 3 times (twice before about 1,900yrBP and once after 1,900yrBP). The frequency of back hillslope denudation at the point of MG3 was totally 5 times (3 times before about 1,900yrBP and twice after about 1,900yrBP) and the moor formations were 3 times (twice before about 1,900yrBP and once after 1,900yrBP). The hillslope surrounded by valley bottom of 'Agol' was confirmed as the pile up of various inorganic matters by the mass movement such as sand or sandy gravel in the valley bottom of the subject area, formed not once but several times of denudation. We could know that the hillslope denudation cycle converged to the time period of $10^2{\sim}10^3$ years. These results will be an important basic data for restoring hillslope denudation process near Asan and changing climate of the Late Quaternary Period.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.886-891
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• 2010

Importance of climate change and its impact on agriculture and environment have increased with a rise of greenhouse gases (GHGs) concentration in Earth's atmosphere, which caus an increase of temperature in Earth. Greenhouse gas emissions such as carbon dioxide ($CO_2$), methane ($CH_4$) and nitrous oxide ($N_2O$) in the Upland field need to be assessed. GHGs fluxes using chamber systems in two upland fields having different soil textures during pepper cultivation (2005) were monitored under different soil textures at the experimental plots of National Academy of Agricultural Science (NAAS), Rural Development Administration (RDA) located in Suwon city, Korea. $CO_2$ emissions were 12.9 tonne $CO_2\;ha^{-1}$ in clay loam soil and 7.6 tonne $CO_2\;ha^{-1}$ in sandy loam soil. $N_2O$ emissions were 35.7 kg $N_2O\;ha^{-1}$ in clay loam soil and 9.2 kg $N_2O\;ha^{-1}$ in sandy loam soil. $CH_4$ emissions were 0.054 kg $CH_4\;ha^{-1}$ in clay loam soil and 0.013 kg $CH_4\;ha^{-1}$ in sandy loam soil. Total emission of GHGs ($CO_2$, $N_2O$, and $CH_4$) during pepper cultivation was converted by Global Warming Potential (GWP). GWP in clay loam soil was higher with 24.0 tonne $CO_2$-eq. $ha^{-1}$ than that in sandy loam soil (10.5 tonne $CO_2$-eq. $ha^{-1}$), which implied more GHGs were emitted in clay loam soil.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.4
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• pp.487-496
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• 2021

Full mouth rehabilitation is re-organizing the occlusion of the remaining teeth and missing teeth considering the functions, esthetics, and neuromuscular harmony. With the loss of multiple teeth, the patient's occlusal plane gradually collapses and the vertical dimension can be reduced. Since reduced vertical dimension can be a potential etiology of the temporomandibular joint and masticatory muscles, prosthetic restoration with increased vertical dimension is required. This case report is about a 68 years old patient with vertical dimension loss due to worn dentition and multiple loss of teeth. In this case, the loss of vertical dimension is assessed carefully using the digital dentistry technology. Using CAD software in digital analysis step, the occlusal plane was established and evaluated using several criteria. Orienting the position of the bone and teeth using CBCT image, patient's condition was visualized in 3 dimension and treatment planning was possible virtually. The information that matches the patient's condylar position with the articulator, which is the virtual face bow, is reproduced on the actual articulator, and evaluated again. After the evaluation, provisional prosthesis was fabricated and it was confirmed that the patient adapts without any abnormality. This was implemented as a final prosthesis. As a result, the patient obtained satisfying results, utilizing the benefits of digital dentistry technology and traditional methods.

• Korean Journal of Heritage: History & Science
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• v.54 no.4
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• pp.174-191
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• 2021

Gangdo (江都), a reproduction of Gaegyeong, was the capital of Goryeo for 39 years. However, due to the urgent wartime situation of the Mongol invasion and the geographical features of Ganghwa Island, the castle system and palace layout were somewhat different from those of Gaegyeong. Gangdo's castle can be understood as a triple castle system consisting of outer castle, middle castle, and inner castle. First, the outer castle was the first to be completed, and it was built at the forefront to prevent the Mongol army from invading in the first place. It is presumed that the section was between Huamdon and Hwadodon in the outer castle during the Joseon Dynasty. The middle castle can be seen as the present 'Middle Castle', a castle built of earth on the outskirts of the Ganghwa-mountain Castle. Considering the sophistication and robustness of the construction method confirmed in the archaeological research, this castle is thought to have been built under a meticulous plan. In other words, as the capital city, it was completed 'at last' as recorded in the Koryo History, after a long 18-year construction process to protect palaces, government offices, and private houses. The inner castle was a castle with the character of a palace. This corresponds to the Old Castle of Ganghwabu (江華府) during the Joseon Dynasty, and it almost coincided with the scale of the composition of Gaegyeong's palace castle. It was a complex functional space, featuring the integration of the palace and the imperial castle, where the main government offices and ancillary facilities, including the palace, were located. Based on the documentary record that these palaces were similar to Gaegyeong's palace, the palace map was overlapped with that of Gaegyeong. The central axis of the building from Seungpyeongmun (昇平門) to Seongyeongjeon (宣慶殿) coincided with Kim Sangyongsunjeol Monument in Ganghwa- Goryeo Palace. Therefore, it seems that the palace of Gangdo had the same basic structure as that of Gaegyeong. However, the inner palace and annexed buildings must have been arranged in consideration of the topographical conditions of Ganghwa, and this is estimated to be the Gunggol area in Gwancheong-ri.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.1135-1147
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• 2021

In order to geometrically correct high-resolution satellite imagery, the sensor modeling process that restores the geometric relationship between the satellite sensor and the ground surface at the image acquisition time is required. In general, high-resolution satellites provide RPC (Rational Polynomial Coefficient) information, but the vendor-provided RPC includes geometric distortion caused by the position and orientation of the satellite sensor. GCP (Ground Control Point) is generally used to correct the RPC errors. The representative method of acquiring GCP is field survey to obtain accurate ground coordinates. However, it is difficult to find the GCP in the satellite image due to the quality of the image, land cover change, relief displacement, etc. By using image maps acquired from various sensors as reference data, it is possible to automate the collection of GCP through the image matching algorithm. In this study, the RPC of KOMPSAT-3A satellite image was corrected through the extracted matching point using the UAV (Unmanned Aerial Vehichle) imagery. We propose a pre-porocessing method for the extraction of matching points between the UAV imagery and KOMPSAT-3A satellite image. To this end, the characteristics of matching points extracted by independently applying the SURF (Speeded-Up Robust Features) and the phase correlation, which are representative feature-based matching method and area-based matching method, respectively, were compared. The RPC adjustment parameters were calculated using the matching points extracted through each algorithm. In order to verify the performance and usability of the proposed method, it was compared with the GCP-based RPC correction result. The GCP-based method showed an improvement of correction accuracy by 2.14 pixels for the sample and 5.43 pixelsfor the line compared to the vendor-provided RPC. In the proposed method using SURF and phase correlation methods, the accuracy of sample was improved by 0.83 pixels and 1.49 pixels, and that of line wasimproved by 4.81 pixels and 5.19 pixels, respectively, compared to the vendor-provided RPC. Through the experimental results, the proposed method using the UAV imagery presented the possibility as an alternative to the GCP-based method for the RPC correction.