• The Journal of Engineering Geology
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• v.32 no.1
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• pp.157-171
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• 2022

Electrical resistivity tomography (ERT) is a traditional and representative geophysical method for determining the resistivity distributions of surrounding soil and rock volumes. Depth resolution profiles and sensitivity distribution sections of the resistivities with respect to various electrode configurations are calculated and investigated using numerical model data. Shallow vertical resolution decreases in the order of Wenner, Schlumberger, and dipole-dipole arrays. A high investigable depth in homogeneous medium is calculated to be 0.11-0.19 times the active electrode spacing, but is counterbalanced by a low vertical resolution. For the application of ERT depth resolution profiles and sensitivity distributions, we provide subsurface structure models for two types of land-creping failure (planar and curved), subvertical fracture, and weathered layer over felsic and mafic igneous rocks. The dipole-dipole configuration appears to be most effective for mapping land-creeping failure planes (especially for curved planes), whereas the Wenner array gives the best resolution of soil horizons and shallow structures in the weathered zone.

• Journal of Intelligence and Information Systems
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• v.28 no.1
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• pp.197-216
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• 2022

With the development of Internet and mobile technology and the spread of social media, a large amount of information is being generated and distributed online. Some of them are useful information for the public, but others are misleading information. The misleading information, so-called 'fake news', has been causing great harm to our society in recent years. Since the global spread of COVID-19 in 2020, much of fake news has been distributed online. Unlike other fake news, fake news related to COVID-19 can threaten people's health and even their lives. Therefore, intelligent technology that automatically detects and prevents fake news related to COVID-19 is a meaningful research topic to improve social health. Fake news related to COVID-19 has spread rapidly through social media, however, there have been few studies in Korea that proposed intelligent fake news detection using the information about how the fake news spreads through social media. Under this background, we propose a novel model that uses Graph2vec, one of the graph embedding methods, to effectively detect fake news related to COVID-19. The mainstream approaches of fake news detection have focused on news content, i.e., characteristics of the text, but the proposed model in this study can exploit information transmission relationships in social engagement networks when detecting fake news related to COVID-19. Experiments using a real-world data set have shown that our proposed model outperforms traditional models from the perspectives of prediction accuracy.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.2
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• pp.265-278
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• 2022

The global energy paradigm is rapidly changing by centering on carbon neutrality, and wind energy is positioning itself as a leader in renewable energy-based power sources. The success of onshore and offshore wind energy projects focuses on securing the economic feasibility of the project, which depends on securing high-quality wind resources and optimal arrangement of wind turbines. In the process of constructing the wind farm, the optimal arrangement method of wind turbines considering the main wind direction is important, and this is related to minimizing the wake effect caused by the fluid passing through the structure located on the windward side. The accuracy of the predictability of the wake effect is determined by the wake model and modeling technique that can properly simulate it. Therefore, in this paper, using WindSim, a commercial CFD model, the wake diffusion pattern is analyzed through the sensitivity study of each wake model of the proposed onshore wind farm located in the mountainous complex terrain in South Korea, and it is intended to be used as basic research data for wind energy projects in complex terrain in the future.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.6
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• pp.239-246
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• 2017

This paper compares the speech signal parameters between Korean and Chinese for Korean pronunciation /ㄹ/, which is caused many errors by Chinese leaners. Allophones of /ㄹ/ in Korean is divided into lateral group and tap group. It has been investigated the reasons for these errors by studying the similarity and the differences between Korean /ㄹ/ pronunciation and its corresponding Chinese pronunciation. In this paper, for the purpose of comparison the speech signal parameters such as energy, waveform in time domain, spectrogram in frequency domain, pitch based on ACF, Formant frequencies are used. From the phonological perspective the speech signal parameters such as signal energy, a waveform in the time domain, a spectrogram in the frequency domain, the pitch (F0) based on autocorrelation function (ACF), Formant frequencies (f1, f2, f3, and f4) are measured and compared. The data, which are composed of the group of Korean words by through a philological investigation, are used and simulated in this paper. According to the simulation results of the energy and spectrogram, there are meaningful differences between Korean native speakers and Chinese leaners for Korean /ㄹ/ pronunciation. The simulation results also show some differences even other parameters. It could be expected that Chinese learners are able to reduce the errors considerably by exploiting the parameters used in this paper.

• Korea Trade Review
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• v.43 no.5
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• pp.25-45
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• 2018

This paper estimates the export losses of the Korean domestic automobile industry due to US trade pressure and its economic ripple effects. Using the HS 6 digit tariff and export data from 2010 to 2017, this paper estimates the tariff elasticity of Korea's US automobile exports against a US tariff increase by applying the Poisson Pseudo maximum likelihood estimation method. After estimating Korea's export losses to the US in three trade pressure scenarios, we estimate its impact on Korean domestic production, value-added and job creation by applying the tariff impact accumulation model based on the industry input-output analysis. Empirical results show that the impact of 25% global tariff by the US on the Korean domestic economy is estimated to result in $30.8 billion in export losses for the five years from 2019 to 2023, about 300 thousand job losses, 88.0 trillion in production inducement losses, and 24.0 trillion in value-added inducement losses. The impacts of withdrawal of the automobile tariff concession are estimated at $4.27 billion export losses and 41.7 thousand job losses. A 15% tariff rate on automobile parts for 3 years is estimated to result in $1.93 billion export losses and 18.7 thousand job losses.

• Korea Trade Review
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• v.41 no.4
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• pp.157-183
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• 2016

This study examines the effects of the acquirer's experience on cross-border mergers and acquisitions(CB M&A) performance. We posit that various types of experience on M&A, including heterogeneity of experience, strategic alliance experience, first CB M&A, domestic and CB M&A experience may have an influence on the performance of CB M&A. The hypotheses are tested with multiple regression on global M&As made by Korean firms over the period of more than fifteen years. The empirical results indicate that firms with domestic M&A experience and the ones with CB M&A experience improve firm performance. Specifically, CB M&A experience more strongly and positively affects CB M&A performance. It also reveals that M&A experience and first CB M&A positively affect CB M&A performance. However, heterogeneity of experience negatively affects CB M&A performance and it has found no significant relationship between strategic alliance and firm performance. In addition, data show that the better explanation is an overall U-shaped relationship than a linear one between CB M&A experience and Performance. Overall, this study contributes to the literature on CB M&A by examining the effect of various types of experience such as heterogeneity of experience and alliance experience and offering a different explanation based on experience, more specifically, addressing the negative relationship between heterogeneity of experience and M&A performance.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.60.3-61
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• 2021

The Korean VLBI Network (KVN) consists of three 21m radio telescopes installed in Seoul, Ulsan, and Jeju Island with the world's first 4-channel receiver that can observe four different frequencies (e.g., 22, 43, 86, 129 GHz) simultaneously. This receiving system of KVN is particularly effective in millimeter-wavelength VLBI (mm-VLBI) observations by compensating fast atmospheric fluctuations effectively. This technology is now being enhanced with a compact triple-band receiver, becoming the world standard for a mm-VLBI system. In 2020, KVN supported 54 observing programs (KVN: 28, EAVN: 26) including the 2nd KVN Key Science Program (KSP) which supports 8Gbps data recording rate and the East Asian VLBI Network (EAVN) programs. KVN also participated in the European VLBI Network (EVN) and GMVA (Global Millimeter VLBI Array) sessions regularly. Here, we report current status and future propsects of KVN.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.6
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• pp.927-937
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• 2018

In this paper the comparative study of the consonants of Pyongyang and Seoul dialects of Korean is performed from the perspective of the signal processing which can be regarded as the basis of engineering applications. Until today, the most of speech signal studies were primarily focused on the vowels which are playing important role in the language evolution. In any language, however, the number of consonants is greater than the number of vowels. Therefore, the research of consonants is also important. In this paper, with the vowel study of the Pyongyang dialect, which was conducted by phonological research and experimental phonetic methods, the consonant studies are processed based on an engineering operation. The alveolar consonant, which has demonstrated many differences in the phonetic value between Pyongyang and Seoul dialects, was used as the experimental data. The major parameters of the speech signal analysis - formant frequency, pitch, spectrogram - are measured. The phonetic values between the two dialects were compared with respect to /시/ and /씨/ of Korean language. This study can be used as the basis for the voice recognition and the voice synthesis in the future.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.12
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• pp.871-879
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• 2017

The purpose of this study is to propose a Busan tourism industry in which the 2016 OECD Tourism policy and ICT convergence platform are applied. OECD proposed 3 policies to promote the tourism industry: First, to maintain the competitiveness of the tourism industry as well as improve its efficiency and sustainability, second, to establish a seamless traffic system, and third, to build a response to the sharing economy. Centering on the OECD's three policies, we propose the developmental possibilities of tourism in Busan. At the same time, we suggest the necessity to build an ICT convergence platform that will help foster the industry. In building an ICT convergence platform, we especially focus on the necessity of: 1. Sharing and creating experience-based interactive contents on the software side, and 2. Developing high quality user experience (UX) and providing a data analysis-based customized service on the hardware side. In addition, we insist on the establishment of the Tourism Promotion Agency for the continuous performance and management of Busan tourism industry. The study ultimately suggests that the construction of ICT convergence platform based on OECD tourism policy can result in the expected outcomes of high effects with low cost for both consumers and suppliers related to the tourism industry.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.148-149
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• 2021

Food waste has increasingly become a global issue of concern among the researchers and policymakers due to its significant environmental and economic impacts, and other associated unsustainable use of resources, including water resources. While food wastage occurs at each stage of the supply chain with food loss at the upstream and food waste at the downstream, the impacts of food waste occurring at the consumption side are enormous due to the accumulated added values. In this study, the embedded water resources, greenhouse gas emissions, and economic loss of household food waste were investigated. The primary granular data of household food waste was collected through direct sampling from 218 selected households of the Buk-gu community in Daegu, South Korea from July 2019 to May 2020. The water footprint, which was based on the water footprint concept, i.e., indirect water use, and GHG emission potential factor for each of the food items were adopted from the literature, while the retail prices and disposal cost were used to assess the economic cost of wasted food items. The water footprint, GHG emission associated with environmental impacts, and the economic cost of 42 major identified wasted food items were conducted. The findings showed that an average of 0.73 ± 0.06 kg/household/day edible food waste was generated among the sampled households, with leafy vegetable, watermelon, and rice responsible for 10, 9, and 4%, respectively, of the total weight of the 42 food wasted items. The water footprint and environmental impact of the household food waste resulted in 0.46 ± 0.04 m³ and 0.71±0.05 kg CO2eq, respectively. Beef, pork, poultry, and rice accounted for 52, 9, 5, and 4% of the total water footprint, while beef, pork, rice, tofu/cheese had 52, 8, 6, and 6% of the total emissions, respectively, embedded in the food wasted. Furthermore, the average estimated economic cost associated with wasted food items was 3855.93±527.27 Korean won, with beef, fish, and leafy vegetable responsible for 21, 13, and 10%, respectively, of the total economic cost. A combined assessment using water-environmental-economic nexus indicated that animal-based food had the highest footprint impacts, with beef, pork, and poultry indicating high indices of 0.3, 0.08, and 0.06 respectively, on a scale of 0 to 1, compared to corn and lettuce with lowest impacts of 0.02. Other food items had moderate impact values ranging from 0.03 to 0.05. This study, therefore, provides insight into the enormity of environmental and economic implications of household food waste among Korean households.