• Resources Recycling
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• v.32 no.1
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• pp.50-59
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• 2023

The amount of dust generated during the dissolution of scrap in an electric arc furnace is approximately 1.5% of the scrap metal input, and it is primarily collected in a bag filter. Electric arc furnace dust primarily consists of zinc and ion. The processing of zinc starts with its conversion into pellet form by the addition of a carbon-based reducing agent(coke, anthracite) and limestone (C/S control). These pellets then undergo reduction, volatilization, and re-oxidation in rotary kiln or RHF reactor to recover crude zinc oxide (60%w/w). Next, iron is discharged from the electric arc furnace dust as a solid called Fe clinker (secondary by-product of the Fe-base). Several methods are then used to treat the Fe clinker, which vary depending on the country, including landfilling and recycling (e.g., subbase course material, aggregate for concrete, Fe-source for cement manufacturing). However, landfilling has several drawbacks, including environmental pollution due to leaching, high landfill costs, and wastage of iron resources. To improve Fe recovery in the clinker, we pulverized it into optimal -sized particles and employed specific gravity and magnetic force selection methods to isolate this metal. A carbon-based reducing agent and a binding material were added to the separated coarse powder (>10㎛) to prepare briquette clinker. A small amount (1-3%w/w) of the briquette clinker was charged with the scrap in an electric arc furnace to evaluate its feasibility as an additives (carbonaceous material, heat-generating material, and Fe source).

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.305-314
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• 2023

With the development of medical technology and radiation treatment equipment, the frequency of high-precision radiation therapy such as intensity modulation radiation therapy has increased. Image-guided radiation therapy has become essential for radiation therapy in precise and complex treatment plans. In particular, with the introduction of imaging equipment for diagnosis in a linear accelerator, CBCT scanning became possible, which made it possible to calibrate and correct the patient's posture through 3D images. Although more precise reproduction of the patient's posture has become possible, the exposure dose delivered to the patient during the image acquisition process cannot be ignored. Radiation optimization is necessary in the field of radiation therapy, and efforts to reduce exposure are necessary. However, when acquiring 3D CBCT images by changing the imaging conditions to reduce exposure, there should be no image quality or artefacts that would make it impossible to align the patient's position. In this study, Rando phantom was used to scan and evaluate images for each shooting condition. The highest SNR was obtained at 100 kV 80 mA 25 ms F1 filter 180°. As the tube voltage and tube current increased, the noise decreased, and the bowtie filter showed the optimal effect at high tube current. Based on the actual scanned images, it was confirmed that patient alignment was possible under all imaging conditions, and that image-guided radiation therapy for patient alignment was possible under the condition of 70 kV 10 mA 20 ms F0 filter 180°, which showed the lowest SNR. In this study, image evaluation was conducted according to the imaging conditions, and low tube voltage, tube current, and small rotation angle scan are expected to be effective in reducing radiation exposure. Based on this, the patient's exposure dose should be kept as low as possible during CBCT imaging.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.441-447
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• 2023

Lead(Pb), which is currently mainly used for shielding purposes in the medical radiation, has excellent radiation shielding functions, but is continuously exposed to radiation directly or indirectly due to the harmfulness of lead itself to the human body and the inconvenience caused by its heavy weight. Research on shielding materials that are human-friendly, lightweight, and convenient to use that can block risks and replace lead is continuously being conducted. In this study, based on the commonly used polyethylene terephthalate (PET) film and the fabric material used in actual radiation protective clothing, a multi-layer thin film was realized through sputtering and vacuum deposition of bismuth, tungsten, and tin, which are metal materials that can shield radiation. Thus, a shielding film was produced and its applicability as a radiation shielding material was evaluated. The radiation shielding film was manufactured by establishing the optimized conditions for each shielding material while controlling the applied voltage, roll driving speed, and gas supply amount to manufacture the shielding film. The adhesion between the parent material and the shielding metal thin film was confirmed by Cross-cut 100/100, and the stability of the thin film was confirmed through a hot water test for 1 hour to measure the change of the thin film over time. The shielding performance of the finally realized shielding film was measured by the Korea association for radiation application (KARA), and the test conditions (inverse wide beam, tube voltage 50 kV, half layer 1.828 mmAl) were set to obtain an attenuation ratio of 16.4 (initial value 0.300 mGy/s, measured value 0.018 mGy/s) and damping ratio 4.31 (initial value 0.300 mGy/s, measured value 0.069 mGy/s) were obtained. by securing process efficiency for future commercialization, light and shielding films and fabrics were used to lay the foundation for the application of films to radiation protective clothing or construction materials with shielding functions.

• Journal of Intelligence and Information Systems
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• v.29 no.2
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• pp.57-84
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• 2023

With the development of information and communications technology (ICT) and big data technology, anyone can easily obtain and utilize vast amounts of data through the Internet. Therefore, the capability of selecting high-quality data from a large amount of information is becoming more important than the capability of just collecting them. This trend continues in academia; literature reviews, such as systematic and non-systematic reviews, have been conducted in various research fields to construct a healthy knowledge structure by selecting high-quality research from accumulated research materials. Meanwhile, after the COVID-19 pandemic, remote healthcare services, which have not been agreed upon, are allowed to a limited extent, and new healthcare services such as health recommender systems (HRS) equipped with artificial intelligence (AI) and big data technologies are in the spotlight. Although, in practice, HRS are considered one of the most important technologies to lead the future healthcare industry, literature review on HRS is relatively rare compared to other fields. In addition, although HRS are fields of convergence with a strong interdisciplinary nature, prior literature review studies have mainly applied either systematic or non-systematic review methods; hence, there are limitations in analyzing interactions or dynamic relationships with other research fields. Therefore, in this study, the overall network structure of HRS and surrounding research fields were identified using citation network analysis (CNA). Additionally, in this process, in order to address the problem that the latest papers are underestimated in their citation relationships, the GraphSAGE algorithm was applied. As a result, this study identified 'recommender system', 'wireless & IoT', 'computer vision', and 'text mining' as increasingly important research fields related to HRS research, and confirmed that 'personalization' and 'privacy' are emerging issues in HRS research. The study findings would provide both academic and practical insights into identifying the structure of the HRS research community, examining related research trends, and designing future HRS research directions.

• Korean Journal of Heritage: History & Science
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• v.55 no.4
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• pp.72-94
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• 2022

This study is about the architectural changes over time in Dongchun-gotaek, the house of Song Jun-gil, one of the representative figures of the Hoseosarim(湖西士林), also an architectural cultural asset representing Daejeon. Data related to Sangryang(上樑) found in the restoration process of Dongchundang(同春堂) and DongchundangJongtaek(同春堂 宗宅), the state designated heritage application report written by Daejeon Metropolitan City, Deokeun-gaseung(德恩家乘), a book which has been handed down from generation to generation from Dongchundang Munjeonggongpa(同春堂 文正公派) of Eunjin Song's Clan and the results of partial excavation surveys respectively conducted in 2010 and 2020 were used as basic research data, and these data were compared and analyzed to examine the changes of the arrangement of Dongchundang, Jeongchim(正寢), and ancestral shrine buildings. Dongchundang was built by Song Jun-Gil. Rather than a new building, it was a building that was basically relocated to its current area when Cheongjwawa(淸坐窩), which was built by his father, dilapidated, and the timing of its construction can be clarified through Sangryangmun(上樑文). However, in the estimated area of Cheongjwawa, no exact site was found in two surveys of buried cultural heritages. In the case of Jeongchim, it was possible to confirm that it had been relocated two times, and it can be said that the biggest achievement of this study was to confirm that the first relocation was outside the current fence. In addition, one of the building sites which was identified in the excavation survey for confirming the servants' quarters was estimated to be the first construction at the site of Dongchun-gotaek. In the shrine area, there were the first constructed Gamyo(家廟), including Byeolmyo(別廟) dedicated to Bulcheonwi(不遷位), and Jomyo(祧廟) dedicated to Checheon(遞遷), and it can be seen that it was a space where many changes such as new construction, demolition, or mutual exchange of location occurred over time. The present buildings arrangement through these processes was not far from the original plan of Song Joon-gil. Therefore, the name of 'Dongchun-gotaek' is appropriate.

• Korean Journal of Heritage: History & Science
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• v.55 no.4
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• pp.96-116
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• 2022

The Daebodan was an altar, which held a memorial service for emperors of the Ming dynasty. This alter, which was referred to as Hwangdan, was first constructed in 1704. When the Japanese Invasion of Korea commenced in 1592, Shinjong, the emperor of the Ming dynasty, sent reinforcements to Josun to help. This alter was made to repay Shinjong's kindness. Before this, Song-siyeol(宋時烈), Leader of Noron(老論), made a shrine at Hwayangdong to hold memorial services for Shinjong, and after some time, this developed into a national ceremony. Construction of the Daebodan largely changed the backyard of Changdukgung-palace. However considering the construction process, the meaning of the Daebodan was not a big deal. At first, the optimal place for the Daebodan was selected at the site of a inner icehouse. But the inner icehouse could not be transferred to other site due to the circumstances. After all, the Daebodan was constructed at the site of Byeoldaeyeong(別隊營) which was located in the outside of palace. Most of the stones for the new Daebodan were used ones. And the annexe of Byeoldaeyeong was used for Daebodan without any changes being made. The scale of the construction was not particularly grand. After the construction, Sukjong, who made the Daebodan, showed barely any interest in it. But the conception of the Daebodan was back again in the history by Youngjo. He was also not interested in the Daebodan during his early years of ruling time. However, in the 1740's, he started to become interested in the ceremony of Daebodan, and carried out a large-scale reconstruction of the Daebodan. Jegigo(祭器庫) was rebuilt In 1739. And Jaesil(齋室), staying one night before the ceremonial day, was added in 1745. In 1749, the Daebodan was greatly changed by enshrining Uijong and Taejo, emperors of the Ming dynasty. The shape of alter was changed. Moreover this alter was made by newly quarried stones. And several buildings, Junsachung(典祀廳), Jaesaengchung(宰牲廳) and Akgongchung(樂工廳), were added to the site. In 1762, meritorious retainers were enshrined to the Daebodan. After all the Daebodan became an important part of the backyard of Changdukgung-palace. During the reign of Jungjo, the Daebodan also was an important part of backyard of Changdukgung-palace. But significant changes were not made at that time. The only change was the moving of Kyungbonggak(敬奉閣) in 1799. Afterward the Daebodan remained unchanged. The ceremonies at the Daebodan stopped in 1908. And the Daebodan disappeared into the mist of history.

• Korean Journal of Heritage: History & Science
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• v.55 no.4
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• pp.138-164
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• 2022

The Neolithic shell midden in Daejuk-ri, Seosan, is distributed on the gentle slope of a low hill close to the west coast. The bedrock of the area consists mainly of schist with various mafic minerals, but shows a partial gneiss pattern. The site consists of loamy topsoil and clay loam subsoil, and the degree of siallization is relatively low. Although the pottery excavated from the shell midden shares mostly similar features, a variety of shapes and patterns coexist. The surface colors, thickness and physical properties are slightly different. The pottery can be subdivided into three types (IA, IB and II) according to the composition of the body clay, the temper and the existence of a black core. Types IA and IB are colorless mineral pottery with a non-black or black core respectively. TypeII is colored mineral pottery with a non-black core. Type I pottery also contains non-plastic colored minerals, but type II contains a large amount of biotite, chlorite, talc, amphibole, diopside and tremolite, which include a large amount of Mg and Fe. The studied pottery contains a small amount of organic matter. Considering the grain size and relatively poor sorting and roundness of the non-plastic particles, the pottery appears to be made by adding coarse non-plastic tempers for special purposes to the untreated weathered soil around the site. The three types of pottery seem to have been incompletely fired in general. While type IB has the lowest degree of oxidation, typeII shows the highest degree of redness and oxidation. It can be interpreted that these differences depend on the firing temperature and the ratio of non-plastic particles. Through a synthesis of the minerals, geochemical data and thermal history, it can be determined that the firing temperature ranged from 600 to 700℃. The pottery types of the Daejuk-ri Shell Midden have slightly different production conditions, mineral compositions, and physical properties, but have undergone similar production processes with basically the same clay materials. The clay is almost identical to the composition of the bedrock and weathered soil distributed in the Daejuk-ri area. Currently, there is an industrial complex in the area, so it is difficult to confirm the soil and geological distribution of the site. However, it is highly probable that the area around the site was self-sufficient for the clay and tempers required for the production of the Neolithic pottery. Therefore, it can be interpreted that the group that left the shell midden in Daejuk-ri lived near the site, visited the site for the purpose of collecting and processing shellfish, and discarded the broken pottery along with shells.

• Korean Journal of Heritage: History & Science
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• v.55 no.4
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• pp.166-177
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• 2022

The Shiveet Khairkhan is located on Tsengel Som in the middle of Bayan-ulgi Aimag in the Altai region. Various remains have been identified, and it has been found to be an important area of the Eurasian steppe. In this study, the characteristics of textile fibers and dyes excavated from the tombs of the 1st~3rd century Xianbei period in the sites of Shiveet Khairkhan, Mongolia were investigated. As a result of analysis using optical microscopic observation and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) for fiber identification, green and yellow fabrics were identified as silk fabrics. To investigate the properties of the dye, the surface reflectance of the dyed fabric was measured using an fiber optic reflectance spectrophotometer for non-destructive analysis. The green fabric appeared similar to the reflection spectrum of indigo dye. In addition, as a result of component analysis using gas chromatography-mass spectrometry, isatin and indigotine were detected. Isatin and indigotine are characteristic components of indigo dye, and it was found that the green fabric of the tombs of the Xianbei period was dyed using indigo dye. It was difficult to identify the type of dye in the yellow fabric as a result of reflectance spectrum and gas chromatography analysis. Indigo plants are a dye used for blue dyeing from thousands of years ago, and many species are distributed around the world. It was confirmed that the fabric was relatively well preserved and indigo dye was used for the green Jikryeongui (garment with a straight collar) in the ancient tomb of the Xianbei period about 1,800 years ago, even though it was buried for a long time. Scientific investigation of textile cultural heritage is an essential process for conservation treatment, restoration, exhibition, and the creation of a conservation environment. It is expected that related research will be activated in the future and will be helpful in interpreting the living culture at the time, preserving textiles, and a conservation environment.

• Korean Journal of Heritage: History & Science
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• v.55 no.4
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• pp.180-193
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• 2022

The East Nine Royal Tombs is a representative place in the Royal Tombs of Joseon (a World Heritage Site). It consists of 1,289 stone artifacts including 979 related stone structures, 310 stone statues, and objects. Most of the stone structures in the East Nine Royal Tombs are composed of biotite granite, but some tombs are composed of light red granite. As a result of magnetic susceptibility measurement, the average data from Geonwolleung to Mongneung, excluding Hyeolleung, were similar, so it is estimated that stones were obtained from the same quarry. In the case of Sungneung, Sureung, and Gyeongneung, the range of susceptibility measurement is widely distributed. It assumed that the newly produced stones were mixed in the moving and construction process. Also, stones might be gathered from different quarries. As a result of a conservation status investigation, both the mound member and the ridge stone had the highest damage rate due to peeling and granular decomposition according to surface weathering. In the case of surface discoloration, yellowing and soils were found in the burial mound members. Yellowing, blackening, and soil were identified in the ridge stone structures. Bio-degradation is the major factor of deterioration of the East Nine Royal Tombs and the conservation status of the tombs were detected as grades 4 to 5. It seems that it is easy for the environment of the royal tombs to form soil for the microorganisms and fine conditions for continuous moisture. In the case of structures, they are in relatively good condition. As a result of a comprehensive damage rating for each tomb, the overall condition is good, but the Geonwolleung Royal Tomb and Hyeolleung Tomb, which were created in the early period, had relatively high weathering ratings. Stone objects in East Nine Royal Tombs have lost many pieces and gateway members due to surface deterioration. Also, secondary damage is ongoing. Each damage factor of the stone artifacts of the East Nine Royal Tombs combines to cause various and continuous damages. Therefore, it is necessary to establish regular conservation status data of the stone artifacts for efficient management after processing as well as conservation treatment of the royal tombs, and specific management manuals and systems. This study investigated the conservation status of stone structures in the East Nine Royal Tombs, a World Heritage Site, and systematically classified them to provide priority and necessity for conservation processing. We look forward to establishing a plan for the conservation and management of the East Nine Royal Tombs with this database in the future.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.6-7
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• 2021

Vegetation development in rivers is one of the important issues not only in academic fields such as geomorphology, ecology, hydraulics, etc., but also in river management practices. The problem of river vegetation is directly connected to the harmony of conflicting values of flood management and ecosystem conservation. In Korea, since the 2000s, the issue of river vegetation and land formation has been continuously raised under various conditions, such as the regulating rivers downstream of the dams, the small eutrophicated tributary rivers, and the floodplain sites for the four major river projects. In this background, this study proposes a method for classifying the distribution of vegetation in rivers based on remote sensing data, and presents the results of applying this to the Naeseong Stream. The Naeseong Stream is a representative example of the river landscape that has changed due to vegetation development from 2014 to the latest. The remote sensing data used in the study are images of Sentinel 1 and 2 satellites, which is operated by the European Aerospace Administration (ESA), and provided by Google Earth Engine. For the ground truth, manually classified dataset on the surface of the Naeseong Stream in 2016 were used, where the area is divided into eight types including water, sand and herbaceous and woody vegetation. The classification method used a random forest classification technique, one of the machine learning algorithms. 1,000 samples were extracted from 10 pre-selected polygon regions, each half of them were used as training and verification data. The accuracy based on the verification data was found to be 82~85%. The model established through training was also applied to images from 2016 to 2020, and the process of changes in vegetation zones according to the year was presented. The technical limitations and improvement measures of this paper were considered. By providing quantitative information of the vegetation distribution, this technique is expected to be useful in practical management of vegetation such as thinning and rejuvenation of river vegetation as well as technical fields such as flood level calculation and flow-vegetation coupled modeling in rivers.