• Journal of Intelligence and Information Systems
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• v.27 no.3
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• pp.1-27
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• 2021

The entire tourism industry is being hit hard by the COVID-19 as a global pandemic. Accommodation sharing services such as Airbnb, which have recently expanded due to the spread of the sharing economy, are particularly affected by the pandemic because transactions are made based on trust and communication between consumer and supplier. As the pandemic situation changes individuals' perceptions and behavior of travel, strategies for the recovery of the tourism industry have been discussed. However, since most studies present macro strategies in terms of traditional lodging providers and the government, there is a significant lack of discussion on differentiated pandemic response strategies considering the peculiarity of the sharing economy centered on peer-to-peer transactions. This study discusses the marketing strategy for individual hosts of Airbnb during COVID-19. We empirically analyze the effect of changes in listing descriptions posted by the Airbnb hosts on listing performance after COVID-19 was outbroken. We extract nine aspects described in the listing descriptions using the Attention-Based Aspect Extraction model, which is a deep learning-based aspect extraction method. We model the effect of aspect changes on listing performance after the COVID-19 by observing the frequency of each aspect appeared in the text. In addition, we compare those effects across the types of Airbnb listing. Through this, this study presents an idea for a pandemic crisis response strategy that individual service providers of accommodation sharing services can take depending on the listing type.

• Journal of the Korean GEO-environmental Society
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• v.20 no.11
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• pp.11-22
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• 2019

Limit state design (LSD) and allowable stress design (ASD) are two main types of soil nailing design methodologies. In the LSD method, stability is determined by applying individual coefficients to ground strength, working load and etc. The ASD method calculates the safety factor and compares it with the minimum safety factor to determine the stability. The global design trend of soil nailing system is changing from the ASD method to the LSD method. The design method in Korea still adopts the ASD philosophy while others mostly do the limit state design. In this study, four soil nail design methods, 'FHWA GEC 7' in U.S. (2015), 'Clouterre' in France (1991), 'Soil nailing - best practice guidance' in U.K. (2005), 'Geoguide 7' in Hongkong (2008), and 'Design guide for slope in construction work' in Korea (2016) were applied to the evaluation of the stability and the results were analyzed comparatively in brief. It is revealed that the design method of 'the overall stability of soil nail walls' in Korea is the most conservative and next those by FHWA, Clouterre and CIRIA become more conservative in order. However, the difference of results obtained from FHWA and Clouterre is negligible. Also, this study found out that efforts to improve domestic design criterion are needed.

• Resources Recycling
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• v.29 no.6
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• pp.125-132
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• 2020

Enrichment possibilities for recovering rare earth elements contained in coal bottom ash generated from domestic circulating fluidized bed combustion (CFBC) were identified. The transport characteristics of the REEs according to the separation and removal of major minerals were evaluated using sieving and leaching process. The main minerals of bottom ash were identified as anhydrite, magnetite, and quartz, and this was confirmed as a 30% of REE content of the world's average coal ash REE value (404 ppm) as a result of the difference in the combustion characteristics of power plants (REE contents in starting material: 123 ppm). More than 90% of the REEs contained in the bottom ash were found to move mainly with magnetite, and less than 10% of the components were found to move with the quartz. Therefore, In order to recover rare earth elements from coal bottom ashes generated from CFBC boiler, it is necessary to select the main rare elements such as magnetite and develop a pretreatment and concentration process.

• The Korean Journal of Applied Statistics
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• v.33 no.6
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• pp.697-712
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• 2020

New infectious diseases have broken out repeatedly across the world over the last 20 years; COVID-19 is causing drastic changes and damage to daily lives. Furthermore, as there is no denying that new epidemics will appear in the future, there is a continuous need to develop measures aimed towards responding to economic damage. Against this backdrop, the living population is an important indicator that shows changes in citizens' life patterns. This study analyzes time-based and socio-environmental characteristics by detecting and classifying changes in everyday life caused by COVID-19 from the perspective of the floating population. k-shape Clustering is used to classify living population data of each of the 424 dong's in Seoul measured by the hour; then by applying intervention analysis and One-way ANOVA, each cluster's characteristics and aspects of change in the living population occurring in the aftermath of COVID-19 are scrutinized. In conclusion, this study confirms each cluster's obvious characteristics in changes of population flows before and after the confirmation of coronavirus patients and distinguishes groups that reacted sensitively to the intervention times on the basis of COVID-related incidents from those that did not.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.439-446
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• 2020

The IMO has adopted emission standards through Annex VI of the International Convention for the Prevention of Pollution from Ships (MARPOL) that strictly prohibit the use of bunker C oil for vessels. In this study, we have adopted the turret-moored Floating LNG-Bunkering Terminal (FLBT) which is designed to receive the LNG from LNGCs and transfer it to LNG-bunkering shuttles in side-by-side moored condition. Numerical analyses were carried out using the high-order boundary-element method for four vessels at various relative distances. Mean wave drift forces were compared in an operational sea state. A model test was performed in the ocean engineering basin at the Korea Research Institute of Ships & Ocean Engineering (KRISO) to verify the safety of the berthing/unberthing operation. In the model test, a jig was designed to simulate tug boats pushing or pulling the bunkering vessels, so that the friction force of the g operation was not affected. Safety depended on the environmental direction, with more stable operation possible if the heading-control function of FLBT is applied to avoid beam-sea conditions.

• Journal of Korean Classical Literature and Education
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• no.39
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• pp.181-220
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• 2018

I analyze Seo Kyung Duk's (徐敬德, 1489-1546) phonetic essay and deduce whether it is related to the Tang poetry style [唐詩風], which was popular in the 16th century. Seo Kyung Duk was known as a Ki[氣]-oriented scholar and a kind of numerologist. He taught people regardless of their status differences, which gave them an open-minded attitude. Most of them were active in the areas near Seoul. Around this time, the Tang poetry style began to be popular in the Yi dynasty. Most of the leading writers of this literary trend were his students. He thought that the universe was made up of the movement of Ki[氣] and that the movement followed the correct order of numbers. Ki[氣] is active, automatic, and inevitably creates the universe in the order of numbers. The reasons for their existence are clear. All present existences, including human beings, fit together and collectively harmonize by themselves. Beyond the present discrimination, the Great Body [本體] returns to a clean and transparent unity. As such, the school presented the political stance of taking the differences of the present world into harmony and the literary position of trying to experience the clean and transparent unity of the Great Body through an aesthetic experience.

• Food Engineering Progress
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• v.22 no.4
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• pp.337-343
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• 2018

Coffee is a commonly consumed beverage that contains anti-inflammatory compounds such as caffeine, chlorogenic acid, cafestol, trigonelline, and kahweol. Lactobacillus plantarum is a lactic acid bacterium most frequently used in the fermentation of food products of plant origin. L. plantarum is able to degrade some food phenolic compounds and provide high value-added compounds such as powerful antioxidants or food additives approved as flavouring agents. In this study, we investigated the anti-inflammatory effects of coffee extract fermented by L. plantarum on RAW264.7 macrophages. In lipopolysaccharide-stimulated RAW264.7 cells, these coffee extracts exhibited anti-inflammatory activities through the reduction of nitric oxide (NO) production and inducible NO synthase expression. Fermented coffee extracts significantly decreased the expression of inflammatory cytokines such as tumor necrosis factor ${\alpha}$, interleukin $1{\beta}$, interleukin 6, and interferon ${\gamma}$. Cyclooxygenase-2, which is one of the key biomarkers for inflammation, was significantly suppressed. These results might be helpful for understanding the anti-inflammatory mechanism of fermented coffee extract on immune cells and, moreover, suggest that fermented coffee extract may be a beneficial anti-inflammatory agent.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.502-510
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• 2021

This study examines gender inequality in the Utopian literature through Bellamy's novelLooking Backward: 2000-1887. Boston, USA, in 2000 is an equal society in which production and distribution are performed efficiently, and everyone can work with an equal opportunity without discrimination. But a closer look at the social structure shows that housework and parenting are predominantly women's duties, and the jobs that women and men can have are differentiating. Therefore, it is hard to say that true gender equality has been achieved. In addition, we could see that there were still remnants of gender inequality, such as showing the notion of beauty judged by male standards. However, Bellamy's Looking Backward: 2000-1887 is meaningful in that it improved women's status and suggested the direction and hope of social development in the 19th century. This study further examined whether these gender inequality factors have disappeared in modern society and confirmed that there remain many gender inequality factors. Therefore, we should all work together to improve the perception of members of society and make changes in social policies so that there is no discrimination between women and men so that we can truly become a gender-equal society.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.33-39
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• 2021

As the interest and demand in the recycled yarn field has increased rapidly worldwide, domestic companies are also promoting research and development and business on recycled yarn. The chemical and thermal properties of four types of virgin and recycled PET samples from A and B company, which are the leading domestic companies in the recycled polyester yarn business, were confirmed through infrared (FT-IR) spectroscopy and differential scanning calorimetry (DSC). Virgin and recycled PET from two companies were compared. FT-IR spectroscopy revealed the typical spectra of PET for both companies and a different peak at 872 cm-1. DSC confirmed that the melting point and crystallization temperature of recycled PET were lower than those of virgin PET. These results indicate that small amounts of contaminants are an important parameter affecting the thermal properties of recycled PET. In the DSC results after seven repeats of the heating and cooling processes, all four samples showed that a lower melting point, crystallization temperature, and low heat flow intensity increased with increasing number of cycles. The results of melting and crystallization enthalpy also showed similar patterns.

• Knowledge Management Research
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• v.22 no.4
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• pp.217-235
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• 2021

As 49% of the world's population uses social media platforms, communication and content sharing within social media are becoming more active than ever. In this environmental base, the one-person media market grew rapidly and formed public opinion, creating a new trend called sell-sumer. This study defined new types of influencers by product category by analyzing the subject concentration of the commercial/non-commercial keywords of influencers and the impact of the ratio of commercial postings on sales. It is hoped that influencers working within social media will be helpful to new sales strategies that are transformed into sell-sumers. The method of this study classifies influencers' commercial/non-commercial posts using Python, performs text mining using KoNLPy, and calculates similarity between FastText-based words. As a result, it has been confirmed that the higher the keyword theme concentration of the influencer's commercial posting, the higher the sales. In addition, it was confirmed through the cluster analysis that the influencer types for each product category were classified into four types and that there was a significant difference between groups according to sales. In other words, the implications of this study may suggest empirical solutions of social media sales strategies for influencers working on social media and marketers who want to use them as marketing tools.