• Title/Summary/Keyword: Frequency response characteristics

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Installation of Very Broadband Seismic Stations to Observe Seismic and Cryogenic Signals, Antarctica (남극 지진 및 빙권 신호 관측을 위한 초광대역 지진계 설치)

  • Lee, Won-Sang;Park, Yong-Cheol;Yun, Suk-Young;Seo, Ki-Weon;Yee, Tae-Gyu;Choe, Han-Jin;Yoon, Ho-Il;Chae, Nam-Yi
    • Geophysics and Geophysical Exploration
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    • v.15 no.3
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    • pp.144-149
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    • 2012
  • Korea Polar Research Institute (KOPRI) has successfully installed two autonomous very broadband three-component seismic stations at the King George Island (KGI), Antarctica, during the 24th KOPRI Antarctic Summer Expedition (2010 ~ 2011). The seismic observation system is originally designed by the Incorporated Research Institutions for Seismology Program for Array Seismic Studies of the Continental Lithosphere Instrument Center, which is fully compatible with the Polar Earth Observing Network seismic system. The installation is to achieve the following major goals: 1. Monitoring local earthquakes and icequakes in and around the KGI, 2. Validating the robustness of seismic system operation under harsh environment. For further intensive studies, we plan to move and install them adding a couple more stations at ice shelf system, e.g., Larsen Ice Shelf System, Antarctica, in 2013 to figure out ice dynamics and physical interaction between lithosphere and cryosphere. In this article, we evaluate seismic station performance and characteristics by examining ambient noise, and provide operational system information such as frequency response and State-Of-Health information.

A Study on the Prediction Function of Wind Damage in Coastal Areas in Korea (국내 해안지역의 풍랑피해 예측함수에 관한 연구)

  • Sim, Sang-bo;Kim, Yoon-ku;Choo, Yeon-moon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.4
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    • pp.69-75
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    • 2019
  • The frequency of natural disasters and the scale of damage are increasing due to the abnormal weather phenomenon that occurs worldwide. Especially, damage caused by natural disasters in coastal areas around the world such as Earthquake in Japan, Hurricane Katrina in the United States, and Typhoon Maemi in Korea are huge. If we can predict the damage scale in response to disasters, we can respond quickly and reduce damage. In this study, we developed damage prediction functions for Wind waves caused by sea breezes and waves during various natural disasters. The disaster report (1991 ~ 2017) has collected the history of storm and typhoon damage in coastal areas in Korea, and the amount of damage has been converted as of 2017 to reflect inflation. In addition, data on marine weather factors were collected in the event of storm and typhoon damage. Regression analysis was performed through collected data, Finally, predictive function of the sea turbulent damage by the sea area in 74 regions of the country were developed. It is deemed that preliminary damage prediction can be possible through the wind damage prediction function developed and is expected to be utilized to improve laws and systems related to disaster statistics.

Characteristics of Affective Optimization in Elderly Koreans (정서경험 빈도와 정서조절 방향에 나타난 한국 노인의 정서최적화 특징)

  • An, Mi So;Ghim, Hei-Rhee
    • 한국노년학
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    • v.37 no.1
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    • pp.201-219
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    • 2017
  • This study was performed to test the socioemotional selectivity theory (SST) with Korean adults. According to SST, perceiving their life as limited, people are motivated to enhance their mood by regulating their mood in such a way to maximize the positive emotions and weaken the negative ones. Being founded on the dialectical constructs which assume the positive and negative sides of emotional experience coexist, Korean adults were supposed to be less motivated to maximize positive emotions and weaken negative emotions. Thus the elderly koreans might regulate emotions not in the direction of maximizing the positive emotions and weakening the negative ones, but in the direction of not being highly aroused. 166 youth, middle-aged, and elderly were asked to rate the frequencies of 31 positive and negative emotions they had experienced during the last month. In addition, they were asked to judge whether they weaken / adapt / maximize their emotions after experiencing positive and negative events. The elderly experienced less positive emotions as well as negative emotions than youth. Youth experienced emotions of high arousal more often than those of low arousal, but the elderly experienced emotions of high arousal less often. The responses of weakening their negative emotions and their positive emotions were largest in the elderly group. On the other hand, the response of maximizing their positive emotions were largest in the youth group. These results show that the elderly maintains emotional stability by weakening both positive and negative emotions of high arousal.

Application of a Geographically Weighted Poisson Regression Analysis to Explore Spatial Varying Relationship Between Highly Pathogenic Avian Influenza Incidence and Associated Determinants (공간가중 포아송 회귀모형을 이용한 고병원성 조류인플루엔자 발생에 영향을 미치는 결정인자의 공간이질성 분석)

  • Choi, Sung-Hyun;Pak, Son-Il
    • Journal of Veterinary Clinics
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    • v.36 no.1
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    • pp.7-14
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    • 2019
  • In South Korea, six large outbreaks of highly pathogenic avian influenza (HPAI) have occurred since the first confirmation in 2003 from chickens. For the past 15 years, HPAI outbreaks have become an annual phenomenon throughout the country and has extended to wider regions, across rural and urban environments. An understanding of the spatial epidemiology of HPAI occurrence is essential in assessing and managing the risk of the infection; however, local spatial variations of relationship between HPAI incidences in Korea and related risk factors have rarely been derived. This study examined whether spatial heterogeneity exists in this relationship, using a geographically weighted Poisson regression (GWPR) model. The outcome variable was the number of HPAI-positive farms at 252 Si-Gun-Gu (administrative boundaries in Korea) level notified to government authority during the period from January 2014 to April 2016. This response variable was regressed to a set of sociodemographic and topographic predictors, including the number of wild birds infected with HPAI virus, the number of wintering birds and their species migrated into Korea, the movement frequency of vehicles carrying animals, the volume of manure treated per day, the number of livestock farms, and mean elevation. Both global and local modeling techniques were employed to fit the model. From 2014 to 2016, a total of 403 HPAI-positive farms were reported with high incidence especially in western coastal regions, ranging from 0 to 74. The results of this study show that local model (adjusted R-square = 0.801, AIC = 954.5) has great advantages over corresponding global model (adjusted R-square = 0.408, AIC = 2323.1) in terms of model fitting and performance. The relationship between HPAI incidence in Korea and seven predictors under consideration were significantly spatially non-stationary, contrary to assumptions in the global model. The comparison between global Poisson and GWPR results indicated that a place-specific spatial analysis not only fit the data better, but also provided insights into understanding the non-stationarity of the associations between the HPAI and associated determinants. We demonstrated that an empirically derived GWPR model has the potential to serve as a useful tool for assessing spatially varying characteristics of HPAI incidences for a given local area and predicting the risk area of HPAI occurrence. Considering the prominent burden of HPAI this study provides more insights into spatial targeting of enhanced surveillance and control strategies in high-risk regions against HPAI outbreaks.

Characteristics of Air Stagnation over the Korean Peninsula and Projection Using Regional Climate Model of HadGEM3-RA (한반도 대기정체의 특성 및 지역기후모델 HadGEM3-RA를 이용한 미래 전망)

  • Kim, Do-Hyun;Kim, Jin-Uk;Kim, Tae-Jun;Byon, Jae-Young;Kim, Jin-Won;Kwon, Sang-Hoon;Kim, Yeon-Hee
    • Atmosphere
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    • v.30 no.4
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    • pp.377-390
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    • 2020
  • Not only emissions, but also atmospheric circulation is a key factor that affects local particulate matters (PM) concentrations in Korea through ventilation effects and transboundary transports. As part of the atmospheric circulation, air stagnation especially adversely affects local air quality due to weak ventilation. This study investigates the large-scale circulation related to air stagnation over Korea during winter and projects the climate change impacts on atmospheric patterns, using observed PM data, reanalysis and regional climate projections from HadGEM3-RA with Modified Korea Particulate matter Index. Results show that the stagnation affects the PM concentration, accompanied by pressure ridge at upper troposphere and weaken zonal pressure gradient at lower troposphere. Downscaling using HadGEM3-RA is found to yield Added-Value in the simulated low tropospheric winds. For projection of future stagnation, SSP5-8.5 and SSP1-2.6 (high and low emission) scenarios are used here. It has been found that the stagnation condition occurs more frequently by 11% under SSP5-8.5 and by 5% under SSP1-2.6 than in present-day climate and is most affected by changes in surface wind speed. The increase in the stagnation conditions is related to anticyclonic circulation anomaly at upper troposphere and weaken meridional pressure gradient at lower troposphere. Considering that the present East Asian winter monsoon is mainly affected by change in zonal pressure gradient, it is worth paying attention to this change in the meridional gradient. Our results suggest that future warming condition increase the frequency of air stagnation over Korea during winter with response of atmospheric circulation and its nonlinearity.

The effect of black consumers' perception of behavior on beauty workers' anger and intention to change jobs (블랙컨슈머 행동지각이 미용 종사자의 분노표현과 이직의도에 미치는 영향)

  • Yun, Su-Mi;Choi, Myo-Sun;Seo, Eun-Hee;Yoon, Mi-Hwa
    • Journal of Convergence for Information Technology
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    • v.12 no.5
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    • pp.183-193
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    • 2022
  • The purpose of this study is to analyze the effect of black consumer behavior perception on the anger expression and turnover intention of beauty workers. For data collection, the final 392 copies were used by distributing questionnaires to 400 people for three months from November 1, 2021 to January 31, 2022, centering on beauty service workers in Seoul, Gyeonggi, and Incheon. For data analysis, SPSS 25.0 program was used. Frequency analysis was performed to identify demographic characteristics, and factor analysis and reliability analysis were performed to understand the validity of the measurement tool. Correlation analysis, A regression analysis was performed. As a result of the analysis, the transient and deterrence of black consumers had a positive (+) effect on anger expression, anger suppression, and turnover intention, and anger expression and anger control had a positive (+) effect on turnover intention. Therefore, it is necessary to raise excessive problems of black consumers or eradicate forced services, and it is believed that proper customer response methods and programs for stress relief should be provided by members.

COVID-19-related Korean Fake News Detection Using Occurrence Frequencies of Parts of Speech (품사별 출현 빈도를 활용한 코로나19 관련 한국어 가짜뉴스 탐지)

  • Jihyeok Kim;Hyunchul Ahn
    • Journal of Intelligence and Information Systems
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    • v.29 no.2
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    • pp.267-283
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    • 2023
  • The COVID-19 pandemic, which began in December 2019 and continues to this day, has left the public needing information to help them cope with the pandemic. However, COVID-19-related fake news on social media seriously threatens the public's health. In particular, if fake news related to COVID-19 is massively spread with similar content, the time required for verification to determine whether it is genuine or fake will be prolonged, posing a severe threat to our society. In response, academics have been actively researching intelligent models that can quickly detect COVID-19-related fake news. Still, the data used in most of the existing studies are in English, and studies on Korean fake news detection are scarce. In this study, we collect data on COVID-19-related fake news written in Korean that is spread on social media and propose an intelligent fake news detection model using it. The proposed model utilizes the frequency information of parts of speech, one of the linguistic characteristics, to improve the prediction performance of the fake news detection model based on Doc2Vec, a document embedding technique mainly used in prior studies. The empirical analysis shows that the proposed model can more accurately identify Korean COVID-19-related fake news by increasing the recall and F1 score compared to the comparison model.

Analysis of Runoff Reduction Effect of Flood Mitigation Policies based on Cost-Benefit Perspective (비용-편익을 고려한 홍수 대응 정책의 유출 저감 효과 분석)

  • Jee, Hee Won;Kim, Hyeonju;Seo, Seung Beom
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.43 no.6
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    • pp.721-733
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    • 2023
  • As the frequency of extreme rainfall events increase due to climate change, climate change adaptation measures have been proposed by the central and local governments. In order to reduce flood damage in urban areas, various flood response policies, such as low impact development techniques and enhancement of the capacity of rainwater drainage networks, have been proposed. When these policies are established, regional characteristics and policy-effectiveness from the cost-benefit perspective must be considered for the flood mitigation measures. In this study, capacity enhancement of rainwater pipe networks and low impact development techniques including green roof and permeable pavement techniques are selected. And the flood reduction effect of the target watershed, Gwanak campus of Seoul National University, was analyzed using SWMM model which is an urban runoff simulation model. In addition, along with the quantified urban flooding reduction outputs, construction and operation costs for various policy scenarios were calculated so that cost-benefit analyses were conducted to analyze the effectiveness of the applied policy scenarios. As a result of cost-benefit analysis, a policy that adopts both permeable pavement and rainwater pipe expansion was selected as the best cost-effective scenario for flood mitigation. The research methodology, proposed in this study, is expected to be utilized for decision-making in the planning stage for flood mitigation measures for each region.

Analysis of Flood Level Changes by Creating Nature-based Flood Buffering Section (자연성기반 홍수완충공간 조성에 따른 홍수위 변화 분석)

  • Ryu, Jiwon;Ji, Un;Kim, Sanghyeok;Jang, Eun-kyung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.43 no.6
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    • pp.735-747
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    • 2023
  • In recent times, the sharp increase in extreme flood damages due to climate change has posed a challenge to effectively address flood-related issues solely relying on conventional flood management infrastructure. In response to this problem, this study aims to consider the effectiveness of nature-based flood management approaches, specifically levee retreat and relocation. To achieve this, we utilized a 1D numerical model, HEC-RAS, to analyze the flood reduction effects concerning floodwater levels, flow velocities, and time-dependent responses to a 100-year frequency flood event. The analysis results revealed that the effect of creating a flood buffer zone of the nature-based solution extends from upstream to downstream, reducing flood water levels by up to 30 cm. The selection of the flow roughness coefficient in consideration of the nature-based flood buffer space creation characteristics should be based on precise criteria and scientific evidence because it is sensitive to the flood control effect analysis results. Notably, floodwater levels increased in some expanded floodplain sections, and the reduction in flow velocities varied depending on the ratio of the expanded cross-sectional area. In conclusion, levee retreat and floodplain expansion are viable nature-based alternatives for effective flood management. However, a comprehensive design approach is essential considering flood control effects, flow velocity reduction, and the timing of peak water levels. This study offers insights into addressing the challenges of climate-induced extreme flooding and advancing flood management strategies.

A Study on the Differences in Awareness of the Social Value of Public Libraries between Public library Users and Non-Users: Focused on Paju City (공공도서관의 사회적 가치에 대한 이용자와 비이용자의 인식 차이에 관한 연구 - 파주시를 중심으로 -)

  • Dong-Geun Oh;Dong-Jo Noh
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.35 no.1
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    • pp.47-71
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    • 2024
  • This study aims to compare the awareness of the social value of public libraries between users and non-users to materialize the abstract concept of social value and, thereby, to present measures that can be applied to the library field. For this purpose, a survey was conducted in person or online for 15 days from May 7, 2023, targeting Paju citizens. Frequency analysis, factor analysis, independent samples t-test, and one-way analysis of variance were conducted on 206 valid response copies using SPSS 25.0. In the results, it is shown that, first, for awareness of the social value of public libraries according to socio-demographic characteristics, there were significant differences depending on age, with in particular, awareness among those in their 10s and 40s being higher than other age groups. For awareness of community development, the awareness of the female group was higher than that of the male group, while, for the awareness according to occupation, it is shown that awareness was highest in the following order: student, others, housewife, self-employed, and office worker. Second, for the awareness of the social value of public libraries, the awareness of the user group was higher than that of the non-user group in all areas. Third, for awareness of the social value of public libraries according to the level of library use, there was no significant difference between groups. In conclusion, it is suggested that measures to encourage non-users to become users, develop new content and services targeting male group and those in their 60s, and 20s, and strengthen community activities are needed to raise awareness of the social value of Paju City public libraries in the future.