• Korean Journal of Heritage: History & Science
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• v.52 no.2
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• pp.38-61
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• 2019

Up until the early twentieth century in Germany, there were two research trends: 1) emphasizing objectives and making detailed observations of archaeological artifacts and sites, 2) tracing the remains of specific nations or ethnic groups and defining their temporal-spatial boundaries by conducting research on material culture in terms of nationalism or ethnocentrism. After the Second World War ended and Germany was divided, West German archaeology focused on observations of artifacts and sites, cataloging them, and doing research on chronology and distribution following their own traditional methodologies. East German archaeology attempted to prove the developing process of history and its Marxist principles based upon material culture and to examine the historic value of inherent specific cultural heritage based on criteria regarding how it corresponded to socialism and contributed to the development of socialism. Nevertheless, East and West German archaeology shared traditional archaeological methods inherited from German archaeology since the nineteenth century, and contact between archaeologists in West and East Germany continued to a degree. Furthermore, East German archaeology produced significant archaeological achievements acknowledged by West German and European archaeologists. These facts provided the momentum to complete rapid incorporation of the archaeologies of West and East Germany in spite of a one-sided process imposed by West German archaeology. In the case of Korea, it seems necessary to make an effort to share common research history and traditions and to encourage mutual academic exchange (e.g. joint excavation and archaeological research). Furthermore, it is also imperative to have open-minded attitudes toward accepting substantial results and interpretations achieved by North Korean archaeologists under scrutiny when and where necessary, despite seeming to have been fossilized by Marxism and Juche ideology. Any efforts to narrow the gap in archaeological research and conservation of cultural heritage between the archaeologies of South and North Korea should be made immediately. The case of Germany demonstrates how such a project could proceed efficaciously.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.166-171
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• 2019

This study was conducted to investigate the effect of gaseous chlorine dioxide ($ClO_2$) concentration and treatment method for maintaining marketability in strawberries 'Maehyang' for export. After harvesting strawberry colored with $60{\pm}5%$ of the skin, and the gaseous $ClO_2$ was applied as four treatments in the cold store set with $10^{\circ}C$ which were as follows: i) non-treatment (Control), ii) $0.2mg{\cdot}L^{-1}$ for 30 minutes, iii) $0.4mg{\cdot}L^{-1}$ for 30 minutes, and iv) continuously exposed at $0.4mg{\cdot}L^{-1}$ during the storage period. Weight loss, firmness, soluble solids content, color, incidence of gray mold, and quality grade of strawberries were investigated every 3 days during 16 days storage in cold store. The weight loss was consistently high at $0.2mg{\cdot}L^{-1}\;ClO_2$ treatment, and the weight loss was lower than other treatments when gaseous $ClO_2$ was continuously treated. Firmness was significantly higher at 0.2 and $0.4mg{\cdot}L^{-1}$ $ClO_2$ treatment on the 13th day of storage. Soluble solids content tended to below in continuous gaseous $ClO_2$ treatment. The colors showed no tendency as affected by concentrations and treatment methods of gaseous $ClO_2$. No gray mold was observed in the continuous gaseous $ClO_2$ treatment until the 13th day of storage. The quality grade was lower in gaseous $ClO_2$ treatment group than in the control. As a result, it was possible to decrease the weight loss and the incidence of gray mold by continuously treating the gaseous $ClO_2$ to strawberry 'Maehyang' for export during the storage period after harvest. However, further research is needed on method to maintain quality grades of fruits.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.2
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• pp.173-180
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• 2021

Purpose: The purpose of this study was to evaluate the retentive characteristics of the additional attachments used with implant bar attachment under repeated insertion/removal cycles. Materials and methods: The newly developed attachment and the commercially available attachment were investigated: ADD-Lock (AL), Locator blue (LB). Two fixtures were placed parallel to each other on the custom lower mounting, and patrix of each attachment was fixed to the fixture. Also, the matrix of each attachment was placed on the opposing upper mounting. A universal testing machine was used to measure the retentive force during initial, 100, 250, 500, 1000, 2000, and 2500 repeated insertion/removal cycles. Wear and deformation of the attachment s were observed by scanning electron microscopy (SEM). Mann-Whitney U test (α=.05) and wilcoxon signed-rank test (α=.05) were performed to compare retentive force between each group and before and after 2500 repeated insertion/removal cycles. Results: In terms of initial retentive force and retentive force after 2500 repeated insertion/removal cycles, the AL group (15.24 ± 1.46 N and 9.74 ± 1.16 N) showed significantly smaller values than the LB group (43.53 ± 12.39 N and 22.99 ± 4.77 N) (P<.05). Also, in the loss of retentive force, the AL group (5.50 ± 1.08 N, 36.08%) showed a smaller value than the LB group (20.54 ± 11.89 N, 47.19%) (P<.05). Based on SEM analysis, The AL group showed noticeable wear and deformation in the patrix and the LB group in the matrix. Conclusion: Locator showed a higher initial retentive force than newly developed attachment, while the loss of retentive force was also higher. Both additional attachments are considered to have sufficient retentive force after repeated insertion/removal cycles.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.39 no.3
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• pp.42-55
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• 2021

This study investigated the memories of the natives and the migrants who had been living with the 760-year-old Zelkova serrata located in the Keangnam Apartment Complex in Dogok 1-dong. Place memory is a newly illuminated concept since the 1980s, and is also used as a new research methodology for studying and recording multi-layered memories left in a place based on feelings and traces of vivid memories. The urban development of Gangnam, which began in the 1970s, quickly changed rural to apartment complexes. The natives of Yeokmal were scattered throughout the country, and new migrants moved in. In the process, zelkova serrata was managed in different ways from time to time, and residents also establish relationship in different ways. Natives used to take a rest in the tree or swing at Dan-o, and recognized it as a place to receive the god during the village ritual. In other words, they shared the entire process of life and death and were given various roles depending on the lives of the residents. It is also a direct experience that was experienced in detail and a place where collective memories of residents are melted. On the other hand, with the construction of Keangnam Apartment, the management of zelkova tree has become stricter, making it impossible for migrants to access. Migrants have come to enjoy zelkova serrata visually, and the annual Yeokmal Traditional Festival makes common memories in the city. In addition, many people personified trees and received mental comfort. In addition, the nature of the old big tree was highlighted in the background of the city, and the symbol of "uniqueness and speciality" was newly formed, which led to the formation of pride and attachment. Through the memories of the two subjects' zelkova tree, we were able to examine the memories of the tree value, and management of protected tree in the city.

• Economic and Environmental Geology
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• v.54 no.2
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• pp.233-245
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• 2021

Many studies on the microstructures in rocks have been conducted using experimental methods with various equipment as well as natural rock studies to see the development of microstructures and understand their mechanisms. Grain boundary migration of mineral aggregates in rocks could cause grain growth or grain size changes during metamorphism or deformation as one of the main recrystallization mechanisms. This study suggests improved ways regarding the analog material experiments with reformed equipment to see sequential observations of these grain boundary migration. It can be more efficient than the existing techniques and carry out an appropriate microstructure analysis. This reformed equipment was implemented to enable optical manipulation by mounting polarizing plates capable of rotating operation on a stereoscopic microscope and a deformation rig capable of experimenting with analog materials. The equipment can automatically control the temperature and strain rate of the deformation rig by microcontrollers and programming and can take digital photomicrographs with constant time intervals during the experiment to observe any microstructure changes. The composite images synthesized using images by rotated polarizing plates enable us to see more accurate grain boundaries. As a rock analog material, norcamphor(C7H10O) was used, which has similar birefringence to quartz. Static grain growth and simple shear deformation experiments were performed using the norcamphor to verify the effectiveness of the equipment. The static grain growth experiments showed the characteristics of typical grain growth behavior. The number of grains decreases and the average grain size increases over time. These case experiments also showed a clear difference between the growth curves with three temperature conditions. The result of the simple shear deformation experiment under the medium temperature-low strain rate showed no significant change in the average grain size but presented the increased elongation of grain shapes in the direction of about 53° regarding the direction perpendicular to the shearing direction as the shear strain increases over time. These microstructures are interpreted as both the plastic deformation and the internal recovery process in grains are balanced by the deformation under the given experimental conditions. These experiments using the reformed equipment represent the ability to sequentially observe changing the microstructure during experiments as desired in the tests with the analog material during the entire process.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.5
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• pp.14-27
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• 2019

This study presents a plan for a memorial park that respects the characteristics based on the historical facts for the concept of space of the Gwangju Hospital of Korea Army and the location of the 505 Security Forces, which were designated as historic sites after the 5-18 Democratization Movement. The Gwangju Metropolitan City as it is the location of the 5-18 historic sites, is taking part in the 5-18 Memorial Project, and plans to establish a city park recognizing the historic site of the 5-18 Democratization Movement, which has been preserved only as a memory space to this point. The park is promoting a phased development plan. This study suggests that the 5-18 historic sites can be modernized and that social consensus can establish the framework of the step-by-step planning and composition process to ensure the plans for the space heals wounds while preserving the history. In this paper, we propose a solution to a problem. We solve the approach for space utilization through an analysis of precedent research and planning cases related to park planning at historical sites. In addition to exploring the value of the site, we also describe the space utilization strategy that covers the historical characteristics and facts while maintaining the concept of park planning. As a result of the research, the historic site of the Gwangju Hospital of Korea Army is planned as a park of historical memory and healing in order to solve the problems left behind by the 5-18 Democratization Movement. The historic site of the 505 Security Forces was selected as an area for historical experiences and a place for learning that can be sympathized with by future generations of children and adolescents in terms of expanding and sustaining the memory of the 5-18 Democratization Movement. In the planning stage, the historical sites suggested the direction of space utilization for representation as did the social consensus of citizens, related groups, and specialists. Through this study, we will contribute to construction of a memorial park containing historical values in from 5-18 historic sites. It is meaningful to suggest a direction that can revitalize the life of the city as well as its citizen and can share with the history with future generations beyond being a place to heal wounds and keep alive the memory of the past.

• Korean Journal of Environment and Ecology
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• v.33 no.5
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• pp.525-538
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• 2019

The purpose of this study was to analyze the habitat status and species diversity of benthic diatoms and estimate the applicability of TDI (Trophic Diatom Index) to obtain the basic data for the identification and management of created wetlands in the Nakdong River. We observed a total of 38 families and 173 species of benthic diatom during the survey period, and spring and autumn showed a similar number of species of 156 and 154, respectively. The result of the SOM (Self-Organizing Map) analysis showed that the distribution of benthic diatom was sensitive to environmental factors such as nutrient concentration and rainfall in each wetland. The cluster 1 was characterized by the survey sites of autumn mostly and consisted of points of high TDI, although the nutrients such as total phosphorus and total nitrogen were low, and the species number and abundance of diatoms were low. Conversely, cluster 4 was characterized by the survey sites of spring mostly and consisted of points of low TDI, even though total nitrogen was high. Considering that most of the created wetlands had the reduced inflow and outflow, the increased flow rate in the summer lowers nutrient values in autumn, and the species number and abundance of benthic diatom decreases due to the increase of turbidity, which reduces the light penetrations to the substrates. On the contrary, the TDI value is low in spring because the low water level causes insufficient substrate surface to the benthic diatoms, and it is too early for the establishment and development of saprophilous species. Although various studies have used TDI as an indicator for evaluating the habitat environment and water quality, it is not a good evaluation indicator in this study since the nutrient concentration in the wetlands mostly high as they have a low flow rate and are close to the stagnant area. Nevertheless, additional periodic surveys that comprehensively reflect the fact that the summer rainfall and inflow/outflow regulating function might affect the species diversity and distribution of benthic diatoms are necessary.

• Journal of IKEEE
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• v.25 no.1
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• pp.156-167
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• 2021

In this paper, we propose a digital transceiver unit design for in-building of 5G optical repeaters that extends the coverage of 5G mobile communication network services and connects to a stable wireless network in a building. The digital transceiver unit for driving the proposed 5G optical repeater is composed of 4 blocks: a signal processing unit, an RF transceiver unit, an optical input/output unit, and a clock generation unit. The signal processing unit plays an important role, such as a combination of a basic operation of the CPRI interface, a 4-channel antenna signal, and response to external control commands. It also transmits and receives high-quality IQ data through the JESD204B interface. CFR and DPD blocks operate to protect the power amplifier. The RF transmitter/receiver converts the RF signal received from the antenna to AD, is transmitted to the signal processing unit through the JESD204B interface, and DA converts the digital signal transmitted from the signal processing unit to the JESD204B interface and transmits the RF signal to the antenna. The optical input/output unit converts an electric signal into an optical signal and transmits it, and converts the optical signal into an electric signal and receives it. The clock generator suppresses jitter of the synchronous clock supplied from the CPRI interface of the optical input/output unit, and supplies a stable synchronous clock to the signal processing unit and the RF transceiver. Before CPRI connection, a local clock is supplied to operate in a CPRI connection ready state. XCZU9CG-2FFVC900I of Xilinx's MPSoC series was used to evaluate the accuracy of the digital transceiver unit for driving the 5G optical repeater proposed in this paper, and Vivado 2018.3 was used as the design tool. The 5G optical repeater digital transceiver unit proposed in this paper converts the 5G RF signal input to the ADC into digital and transmits it to the JIG through CPRI and outputs the downlink data signal received from the JIG through the CPRI to the DAC. And evaluated the performance. The experimental results showed that flatness, Return Loss, Channel Power, ACLR, EVM, Frequency Error, etc. exceeded the target set value.

• Journal of Nutrition and Health
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• v.53 no.6
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• pp.676-687
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• 2020

Purpose: The purpose of this study was to investigate the differences in portion size of 11 types of foods that Korean adults frequently consume, based on the parameters of eating place, gender, and age using the Korea National Health and Nutrition Examination Survey (KNHANES) data. Methods: The dietary survey data from 2012-2016 KNHANES was used. A total of 19,779 subjects (8,034 male [40.6%], 11,745 female [59.4%]) were classified based on gender, three age groups (19-29 years old [15.7%], 30-49 years old [46.9%], 50-64 years old [37.4%]) and three eating places (home, institution, and restaurants/convenient stores etc.). Results: The portion sizes according to the eating places were calculated as per the median intake of Korean adults. Foods that showed the highest median intake in restaurants/convenience stores were boiled rice and kimchi stew. The median intake quantity of kimchi stew was the highest in restaurants/convenience stores in men across most age groups. Women in 30-49 years age group also consumed a lot of kimchi stew in restaurants/convenience stores. Men in the age groups 30-49 and 50-64 years consumed soybean paste stew the most in institutions compared to home and restaurants/convenient stores. Stir-fried pork was consumed the most at institutional meal places across all age groups. Conclusion: The portion sizes of kimchi stew and boiled rice were the highest in restaurants/convenience stores. As kimchi stew and soybean paste stew is high in sodium, the intake should be reduced in institutions and restaurants/convenience stores. Furthermore, it is necessary to reduce sodium intake through consumer nutrition education and the development of low-salt standard recipes for restaurants.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.531-542
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• 2021

Open-pit mines require constant monitoring as they can cause surface changes and environmental disturbances. In open-pit mines, there is little vegetation at the mining site and can be monitored using InSAR (Interferometric Synthetic Aperture Radar) coherence imageries. In this study, activities occurring in mine were analyzed by applying the recently developed InSAR coherence-based NDAI (Normalized Difference Activity Index). The March 5 Youth Mine is a North Korean mine whose development has been expanded since 2008. NDAI analysis was performed with InSAR coherence imageries obtained using Sentinel-1 SAR images taken at 12-day intervals in the March 5 Youth Mine. First, the area where the elevation decreased by about 75.24 m and increased by about 9.85 m over the 14 years from 2000 was defined as the mining site and the tailings piles. Then, the NDAI images were used for time series analysis at various time intervals. Over the entire period (2017-2019), average mining activity was relatively active at the center of the mining area. In order to find out more detailed changes in the surface activity of the mine, the time interval was reduced and the activity was observed over a 1-year period. In 2017, we analyzed changes in mining operations before and after artificial earthquakes based on seismic data and NDAI images. After the large-scale blasting that occurred on 30 April 2017, activity was detected west of the mining area. It is estimated that the size of the mining area was enlarged by two blasts on 30 September 2017. The time-averaged NDAI images used to perform detailed time-series analysis were generated over a period of 1 year and 4 months, and then composited into RGB images. Annual analysis of activity confirmed an active region in the northeast of the mining area in 2018 and found the characteristic activity of the expansion of tailings piles in 2019. Time series analysis using NDAI was able to detect random surface changes in open-pit mines that are difficult to identify with optical images. Especially in areas where in situ data is not available, remote sensing can effectively perform mining activity analysis.