• Journal of Korean Society of Forest Science
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• v.108 no.1
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• pp.40-49
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• 2019

Coarse woody debris (CWD), which is a component of the forest ecosystem, plays a major role in forest energy flow and nutrient cycling. In particular, CWD isolates carbon for a long time and is important in terms of slowing the rate of carbon released from the forest to the atmosphere. Therefore, this study measured the physiochemical characteristics and respiration rate ($R_{CWD}$) of CWD for Larix kaempferi and Pinus rigida in temperate forests in central Korea. In summer 2018, CWD samples from decay class (DC) I to IV were collected in the 14 forest stands. $R_{CWD}$ and physiochemical characteristics were measured using a closed chamber with a portable carbon dioxide sensor in the laboratory. In both species, as CWD decomposition progressed, the density ($D_{CWD}$) of the CWD decreased while the water content ($WC_{CWD}$) increased. Furthermore, the carbon concentrations did not significantly differ by DC, whereas the nitrogen concentration significantly increased and the C/N ratio decreased. The respiration rate of L. kaempferi CWD increased significantly up to DC IV, but for P. rigida it increased to DC II and then unchanged for DC II-IV. Accordingly, except for carbon concentration, all the measured characteristics showed a significant correlation with $R_{CWD}$. Multiple linear regression showed that $WC_{CWD}$ was the most influential factor on $R_{CWD}$. $WC_{CWD}$ affects $R_{CWD}$ by increasing microbial activity and is closely related to complex environmental factors such as temperature and light conditions. Therefore, it is necessary to study their correlation and estimate the time-series pattern of CWD moisture.

• Journal of Environmental Impact Assessment
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• v.30 no.5
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• pp.271-296
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• 2021

Since the thermal stratification in a reservoir inhibits the vertical mixing of the upper and lower layers and causes the formation of a hypoxia layer and the enhancement of nutrients release from the sediment, changes in the stratification structure of the reservoir according to future climate change are very important in terms of water quality and aquatic ecology management. This study was aimed to develop a data-driven inflow water temperature prediction model for Daecheong Reservoir (DR), and to predict future inflow water temperature and the stratification structure of DR considering future climate scenarios of Representative Concentration Pathways (RCP). The random forest (RF)regression model (NSE 0.97, RMSE 1.86℃, MAPE 9.45%) developed to predict the inflow temperature of DR adequately reproduced the statistics and variability of the observed water temperature. Future meteorological data for each RCP scenario predicted by the regional climate model (HadGEM3-RA) was input into RF model to predict the inflow water temperature, and a three-dimensional hydrodynamic model (AEM3D) was used to predict the change in the future (2018~2037, 2038~2057, 2058~2077, 2078~2097) stratification structure of DR due to climate change. As a result, the rates of increase in air temperature and inflow water temperature was 0.14~0.48℃/10year and 0.21~0.41℃/10year,respectively. As a result of seasonal analysis, in all scenarios except spring and winter in the RCP 2.6, the increase in inflow water temperature was statistically significant, and the increase rate was higher as the carbon reduction effort was weaker. The increase rate of the surface water temperature of the reservoir was in the range of 0.04~0.38℃/10year, and the stratification period was gradually increased in all scenarios. In particular, when the RCP 8.5 scenario is applied, the number of stratification days is expected to increase by about 24 days. These results were consistent with the results of previous studies that climate change strengthens the stratification intensity of lakes and reservoirs and prolonged the stratification period, and suggested that prolonged water temperature stratification could cause changes in the aquatic ecosystem, such as spatial expansion of the low-oxygen layer, an increase in sediment nutrient release, and changed in the dominant species of algae in the water body.

• Atmosphere
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• v.31 no.2
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• pp.229-240
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• 2021

The Global Ocean Data Assimilation and Prediction System (GODAPS) in operation at the KMA (Korea Meteorological Administration) is introduced. GODAPS consists of ocean model, ice model, and 3-d variational ocean data assimilation system. GODAPS assimilates conventional and satellite observations for sea surface temperature and height, observations of sea-ice concentration, as well as temperature and salinity profiles for the ocean using a 24-hour data assimilation window. It finally produces ocean analysis fields with a resolution of 0.25 ORCA (tripolar) grid and 75-layer in depth. This analysis is used for providing a boundary condition for the atmospheric model of the KMA Global Seasonal Forecasting System version 5 (GloSea5) in addition to monitoring on the global ocean and ice. For the purpose of evaluating the quality of ocean analysis produced by GODAPS, a one-year data assimilation experiment was performed. Assimilation of global observing system in GODAPS results in producing improved analysis and forecast fields with reduced error in terms of RMSE of innovation and analysis increment. In addition, comparison with an unassimilated experiment shows a mostly positive impact, especially over the region with large oceanic variability.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.127-137
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• 2021

Air emission charge for nitrogen oxide as a precursor of fine dust has been introduced and implemented within the country from 2020. Therefore, the development of economical combustion technology for NOx reduction has got more needed urgently. This study investigated the air-staging effect as a way to reduce the NOx during combustion of domestic unused forest biomass, recently possible to secure REC (Renewable Energy Certification) as a substitute for overseas wood pellets in a 0.1 MWth circulating fluidized bed combustion test-rig. Operating conditions were comparison with and without air-staging, the supply position of tertiary air (6.4 m, 8.1 m, 9.4 m in the combustor) and variation of air-staging ratio (Primary air:Secondary air:Tertiary air=91%:9%:0%, 82%:9%:9%, 73%:9%:18%). NO and CO concentrations in flue gas, profiles of temperature and pressure at the height of the combustion, unburned carbon in sampled fly ash and combustion efficiency on operating conditions were evaluated. As notable results, NO concentration with air-staging application under tertiary air supply at 9.4 m in the combustor reduced 100.7 ppm compared to 148.8 ppm without air-staging while, CO concentration increased from 52.2 ppm without air-staging to 99.8 ppm with air-staging. However, among air-staging runs, when tertiary air supply amount at 6.4 m in the combustor increased by air-staging ratio (Primary air:Secondary air:Tertiary air=73%:9%:18%), NO and CO concentrations decreased the lowest 90.8 ppm and 66.1 ppm, respectively. Furthermore, combustion efficiency at this condition was improved to 99.3%, higher than that (98.3%) of run without air-staging.

• Journal of the Korean earth science society
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• v.43 no.2
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• pp.239-252
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• 2022

Quality control methods for the first G-band vapor radiometer (GVR) mounted on a weather aircraft in Korea were developed using the GVR Precipitable Water Vapor (PWV). The aircraft attitude information (degree of pitch and roll) was applied to quality control to select the shortest vertical path of the GVR beam. In addition, quality control was applied to remove a GVR PWV ≥20 mm. It was found that the difference between the warm load average power and sky load average power converged to near 0 when the GVR PWV increased to 20 mm or higher. This could be due to the high brightness temperature of the substratus and mesoclouds, which was confirmed by the Communication, Ocean and Meteorological Satellite (COMS) data (cloud type, cloud top height, and cloud amount), cloud combination probe (CCP), and precipitation imaging probe (PIP). The GVR PWV before and after the application of quality control on a cloudy day was quantitatively compared with that of a local data assimilation and prediction system (LDAPS). The Root Mean Square Difference (RMSD) decreased from 2.9 to 1.8 mm and the RMSD with Korea Local Analysis and Precipitation System (KLAPS) decreased from 5.4 to 4.3 mm, showing improved accuracy. In addition, the quality control effectiveness of GVR PWV suggested in this study was verified through comparison with the COMS PWV by using the GVR PWV applied with quality control and the dropsonde PWV.

• Journal of Korea Entertainment Industry Association
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• v.15 no.6
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• pp.35-54
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• 2021

This study examines the characteristics of CBS's Kim Hyun-Jung's News Show(hearafter News Show) and the change to transmedia. The distinguishing characteristics of News Show compared to radio-based current affairs programs are as follows. First, despite its time limit, it adopts the form of investigative reports or investigative documentaries to uncover the truth of the events through 'Detective Son Su-Ho', etc. Second, News show's interviews have avoided biased stance in the reporting of minority issues by interviewing the affected parties anonymously including people involved in incidents and accidents, bereaved families, and other victims. News Show has been producing a transmedia content called 'That Honey Show' (a show that reads comments as fun as honey) since November 2018. 'That Honey Show' is broadcast in real time on YouTube right after the News Show radio broadcast ends. As a form of spin-off content, 'That Honey Show' breaks down the boundaries among staff, MCs, and guests, as well as shifting roles by using 'vice characters'. The female host, Kim conducts interviews with the main characters related to various issues and extends the fixed identity of current affairs shows to the everyday politics and cultural realms. Thus she draws active participation and responses audience. This paper analyzes two representative broadcast cases of 'That Honey Show'-first, the case of resistance and activity of the BTS fandom ARMY in the US presidential election, and, second, the case of reporting on the Nth room incident. This analysis considers the critical participation of digital citizens and the effect of fostering a sense of community in the current affairs show in the transmedia era.

• Journal of the Korean Society for information Management
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• v.39 no.1
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• pp.257-280
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• 2022

In this study, we analyzed comments on news articles of representative companies of the three industries (i.e., semiconductor, secondary battery, and bio industries) that had been listed as national strategic technology projects of South Korea to identify public opinions towards them. In addition, we analyzed the relationship between changes in public opinion and stock price. 'Samsung Electronics' and 'SK Hynix' in the semiconductor industry, 'Samsung SDI' and 'LG Chem' in the secondary battery industry, and 'Samsung Biologics' and 'Celltrion' in the bio-industry were selected as the representative companies and 47,452 comments of news articles about the companies that had been published from January 1, 2020, to December 31, 2020, were collected from Naver News. The comments were grouped into positive, neutral, and negative emotions, and the dynamic topics of comments over time in each group were analyzed to identify the trends of public opinion in each industry. As a result, in the case of the semiconductor industry, investment, COVID-19 related issues, trust in large companies such as Samsung Electronics, and mention of the damage caused by changes in government policy were the topics. In the case of secondary battery industries, references to investment, battery, and corporate issues were the topics. In the case of bio-industries, references to investment, COVID-19 related issues, and corporate issues were the topics. Next, to understand whether the sentiment of the comments is related to the actual stock price, for each company, the changes in the stock price and the sentiment values of the comments were compared and analyzed using visual analytics. As a result, we found a clear relationship between the changes in the sentiment value of public opinion and the stock price through the similar patterns shown in the change graphs. This study analyzed comments on news articles that are highly related to stock price, identified changes in public opinion trends in the COVID-19 era, and provided objective feedback to government agencies' policymaking.

• Korean Journal of Heritage: History & Science
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• v.57 no.1
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• pp.110-123
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• 2024

Onyanghaenggung Palace(temporary palace at Onyang) is an important cultural heritage that can substantially confirm the king's visiting at hot springs based on literature records such as <Ongungyeonggoedae(溫宮靈槐臺)>, <Oncheonhaenggungdo(溫泉行宮圖)> of 『Ongungsasil(溫宮事實)』, <Younggoedaedo(靈槐臺圖)>, 『Younggoedaegi(靈槐臺記)』 and cultural properties such as Yeonggoedae(靈槐臺) and Shinjeong Monument(神井碑). Through a photo taken by Hermann Sander in 1906, it can be confirmed that the hot springs(Tangsil building) at Onyanghaenggung Palace during the Joseon Dynasty was maintained until the early Japanese colonial period. The purpose of this study is to estimate the compositions of the hot springs(Tangsil building) in Onyanghaenggung Palace based on literature records and <Oncheonhaenggungdo>(1795). To achieve these purposes, we firstly examined the changes in Onyanghaenggung Palace and the hot springs (Tangsil building); secondly, the bathing behaviors of kings were reviewed; thirdly, we organized the architectural composition of the hot springs (Tangsil building) according to "Ongung Repair" of 『Ongungsasil (溫宮事實)』; and fourthly, by comparing Sander's photo in the early days of Japanese colonial rule, the architectural composition of the hot springs (Tangsil building) in the late Joseon Dynasty was examined. The results of this study are as follows. First, the hot springs(Tangsil building) of Onyanghaenggung Palace were continuously connected to the Onjeongsil(溫井室) in the reign of King Hyeonjong and maintained until 『Hoseo-eupji』 (1871) in the late Joseon Dynasty. It matches the photograph taken by Hermann Sander(1906) and <1912 Onyang Hot Springs in Asan City>(1912) of Korea Copyright Commission during the early Japanese colonial period. Second, the various king's bathing methods during the Joseon Dynasty were adopted such as washing, spilling and bathing head while sitting on a bathing platform or chair, or exposing the steam of hot spring water, dipping feet into the water and a half-body soaking bath below the navel immersed in water. Third, the stone bathtubs of hot springs(Tangsil building) are composed of the upper bath which was hot spring water gushes out from the northwest, bends to the east, enters the middle bath, and bends to the south to come out to the outside to gather in the lower bath. Around the stone bathtubs, pebble stones brought in from Taean were laid on the floor of the hot springs(Tangsil building). From the above considerations, the compositions of the Tangsil building in Onyang Temporary Palace is based on the king's approach from the main royal building, the king's bathing method and bathing tools, the bathing behavior of enlisted medical officers and bathing assistants, and each rooms mentioned in "Ongung Repair". By comparing it with Hermann Sander's photo, the architectural compositions of the hot springs(Tangsil building) can be estimated.