• Title/Summary/Keyword: 모델 이해

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A Study on the Research Topics and Trends in South Korea: Focusing on Particulate Matter (토픽모델링을 이용한 국내 미세먼지 연구 분류 및 연구동향 분석)

  • Park, Hyemin;Kim, Taeyong;Kwon, Daewoong;Heo, Junyong;Lee, Juyeon;Yang, Minjune
    • Korean Journal of Remote Sensing
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    • v.38 no.5_3
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    • pp.873-885
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    • 2022
  • The particulate matter (PM) has emerged as a hot topic around the world as it has been reported that PM is related to an increase in mortality and prevalence rates. In South Korea, the importance of PM has been recognized since the late 1990s, and various studies on PM have been conducted. This study investigated the PM research topics and trends for papers (D=2,764) published in Research Information Sharing Service (RISS) using topic modeling based on Latent Dirichlet Allocation (LDA). As a result, a total of 10 topics were identified in the whole papers, and the PM research topics were classified as 'PM reduction (Topic 1)', 'Government policy and management (Topic 2)', 'Characteristics of PM (Topic 3)', 'PM model (Topic 4)', 'Environmental education (Topic 5)', 'Bio (Topic 6)', 'Traffic (Topic 7)', 'Asian dust (Topic 8)', 'Indoor PM (Topic 9)', 'Human risk (Topic 10)'. In particular, the proportion of papers on topics 'Government policy and management (Topic 2)', 'PM model (Topic 4)', 'Environmental education (Topic 5)', and 'Bio (Topic 6)' to the toal number of papers increased over time (linear slope > 0). The results of this study provide the new literature review methodology related to particulate matter and the history and insight.

Prediction of KRW/USD exchange rate during the Covid-19 pandemic using SARIMA and ARDL models (SARIMA와 ARDL모형을 활용한 COVID-19 구간별 원/달러 환율 예측)

  • Oh, In-Jeong;Kim, Wooju
    • Journal of Intelligence and Information Systems
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    • v.28 no.4
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    • pp.191-209
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    • 2022
  • This paper is a review of studies that focus on the prediction of a won/dollar exchange rate before and after the covid 19 pandemic. The Korea economy has an unprecedent situation starting from 2021 up till 2022 where the won/dollar exchange rate has exceeded 1,400 KRW, a first time since the global financial crisis in 2008. The US Federal Reserve has raised the interest rate up to 2.5% (2022.7) called a 'Big Step' and the Korea central bank has also raised the interested rate up to 2.5% (2022.8) accordingly. In the unpredictable economic situation, the prediction of the won/dollar exchange rate has become more important than ever. The authors separated the period from 2015.Jan to 2022.Aug into three periods and built a best fitted ARIMA/ARDL prediction model using the period 1. Finally using the best the fitted prediction model, we predicted the won/dollar exchange rate for each period. The conclusions of the study were that during Period 3, when the usual relationship between exchange rates and economic factors appears, the ARDL model reflecting the variable relationship is a better predictive model, and in Period 2 of the transitional period, which deviates from the typical pattern of exchange rate and economic factors, the SARIMA model, which reflects only historical exchange rate trends, was validated as a model with a better predictive performance.

Numerical Study on Impact Resistance of Nonuniform Nacre-patterned Multi-layer Structures (비균일 진주층 모사 다층형 복합재료의 내충격성에 관한 수치해석)

  • Lee, Tae Hee;Ko, Kwonhwan;Hong, Jung-Wuk
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.35 no.4
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    • pp.215-226
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    • 2022
  • Significant efforts have been devoted to developing high-performance composite materials by emulating the structure of biological creatures with superior mechanical characteristics. Nacre has been one of the most sought-after natural structures due to its exceptional fracture toughness compared with the constituent materials. However, the effect of manipulating the nacre-like geometry on the impact performance has not been fully investigated thus far. In this study, composites of randomly manipulated nacreous geometry are numerically developed and the impact performance is analyzed. We develop an algorithm by which the planar area of platelets in the nacre-like design is randomly resized. Thereafter, the numerical models of nonuniform nacre-patterned multi-layer structures are developed and the drop-weight impact simulation is performed. The impact behaviors of the model are evaluated by using the ratio of absorbed energy, the von Mises stress distribution, and the impact force-time curve. Therefore, the effect of the geometric irregularity on the nacre-patterned design is elucidated. This insight can be efficiently utilized in establishing the optimum design of the nacre-patterned structure.

Estimation of Spatial Distribution Using the Gaussian Mixture Model with Multivariate Geoscience Data (다변량 지구과학 데이터와 가우시안 혼합 모델을 이용한 공간 분포 추정)

  • Kim, Ho-Rim;Yu, Soonyoung;Yun, Seong-Taek;Kim, Kyoung-Ho;Lee, Goon-Taek;Lee, Jeong-Ho;Heo, Chul-Ho;Ryu, Dong-Woo
    • Economic and Environmental Geology
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    • v.55 no.4
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    • pp.353-366
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    • 2022
  • Spatial estimation of geoscience data (geo-data) is challenging due to spatial heterogeneity, data scarcity, and high dimensionality. A novel spatial estimation method is needed to consider the characteristics of geo-data. In this study, we proposed the application of Gaussian Mixture Model (GMM) among machine learning algorithms with multivariate data for robust spatial predictions. The performance of the proposed approach was tested through soil chemical concentration data from a former smelting area. The concentrations of As and Pb determined by ex-situ ICP-AES were the primary variables to be interpolated, while the other metal concentrations by ICP-AES and all data determined by in-situ portable X-ray fluorescence (PXRF) were used as auxiliary variables in GMM and ordinary cokriging (OCK). Among the multidimensional auxiliary variables, important variables were selected using a variable selection method based on the random forest. The results of GMM with important multivariate auxiliary data decreased the root mean-squared error (RMSE) down to 0.11 for As and 0.33 for Pb and increased the correlations (r) up to 0.31 for As and 0.46 for Pb compared to those from ordinary kriging and OCK using univariate or bivariate data. The use of GMM improved the performance of spatial interpretation of anthropogenic metals in soil. The multivariate spatial approach can be applied to understand complex and heterogeneous geological and geochemical features.

Effects of Temperature on the Development and Fecundity of Maruca vitrata (Lepidoptera: Crambidae) (콩명나방(Maruca vitrata) (나비목: 포충나방과) 발육과 산란에 미치는 온도의 영향)

  • Jeong Joon, Ahn;Eun Young, Kim;Bo Yoon, Seo;Jin Kyo, Jung;Si-Woo, Lee
    • Korean journal of applied entomology
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    • v.61 no.4
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    • pp.563-575
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    • 2022
  • Maruca vitrata is one of important pests in leguminous crops, especially red bean. We investigated the effects of temperature on development of each life stage, adult longevity and fecundity of M. vitrata for understanding the biological characteristics of the insect species at eight constant temperatures of 13, 16, 19, 22, 25, 28, 31, and 34℃. Eggs hatched successfully at all temperature subjected and larvae successfully developed to the adult stage from 16℃ to 31℃. The developmental period of egg decreased up to 31℃ and after then increased. The developmental period of larva and pupa, and adult longevity of M. vitrata decreased with increasing temperature. Lower and higher threshold temperature (TL and TH) were calculated by the Lobry-Rosso-Flandrois (LRF) and Sharpe-Schoolfield-Ikemoto (SSI) models. The lower developmental threshold (LDT) and thermal constant (K) from egg hatching to adult emergence of M. vitrata were estimated by linear regression as 12.8℃ and 280.8DD, respectively. TL and TH from egg hatching to adult emergence using SSI model were 14.2℃ and 31.9℃. Thermal windows, i.e., the range in temperature between the minimum and maximum rate of development, of M. vitrata was 17.7℃. In addition, we constructed the oviposition models of adult, using the investigated adult traits including survival, longevity, oviposition period and fecundity. Temperature-dependent development models and adult oviposition models will be helpful to understand the population dynamics of M vitrata and to establish the strategy of integrated pest management in legume crops.

Effects of Temperature on the Development and Reproduction of Matsumuraeses phaseoli (Lepidoptera: Tortricidae) (팥나방(Matsumuraeses phaseoli)의 발육과 생식에 미치는 온도의 영향)

  • Jeong Joon, Ahn;Eun Young, Kim;Bo Yoon, Seo;Jin Kyo, Jung
    • Korean journal of applied entomology
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    • v.61 no.3
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    • pp.461-473
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    • 2022
  • Matsumuraeses phaseoli is one of important pests in soybean crops, especially adzuki beans. We investigated the effects of temperature on development of each life stage, adult longevity and fecundity of M. phaseoli for understanding the biological characteristics of M. phaseoli at ten constant temperatures of 7, 10, 13, 16, 19, 22, 25, 28, 31, and 34℃. Eggs hatched successfully at all temperature subjected except 7℃ and 34℃. The developmental period of each life stage and adult longevity of M. phaseoli decreased as temperature increased. Lower and higher threshold temperature (TL and TH) were calculated by the Lobry-Rosso-Flandrois (LRF) and Sharpe-Schoolfield-Ikemoto (SSI) models. The lower developmental threshold (LDT) and thermal constant (K) from egg hatching to adult emergence of M. phaseoli were estimated by linear regression as 9.04℃ and 422.97DD, respectively. TL and TH from egg hatching to adult emergence using SSI model were 20.0℃ and 32.3℃. Thermal windows, i.e., the range in temperature between the minimum and maximum rate of development, of M. phaseoli was 12.3℃. We constructed the adult oviposition model of M. phaseoli using adult survivorship and fecundity. Temperature-dependent development models and adult oviposition models will be helpful to understand the population dynamics of M. falcana and to establish the strategy of integrated pest management in soybean fields.

The Validity Study of the CAPP-SR in Korean Correctional Offenders (자기보고식 사이코패시 성격 종합평가 도구(CAPP-SR) 타당화 연구: 한국 수형자 집단을 중심으로)

  • Sea, Jonghan
    • Korean Journal of Forensic Psychology
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    • v.12 no.3
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    • pp.301-321
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    • 2021
  • The Comprehensive Assessment of Psychopathic Personality(CAPP) is an emerging comprehensive approach that makes use of 99 items in 33 symptoms to well-represented psychopathic personality disorder, but cross-cultural generalizability of this potential model have not endured extensive validation to date. The current study sought to validate the recently published CAPP-Self-Report form(CAPP-SR). 311 participants were derived from eleven prisons by the systematic sampling. They were administered the CAPP-SR, Triarchic Psychopathy Measure(TriPM), Levenson's SRP(LSRP), Short Dark Tetrad(SD-4), and Korean Offender Risk Assessment-General(KORAS-G designed for predicting Korean offenders'recidivism. The results showed that the CAPP-SR total, domain, and symptom scores were generally associated with TriPM, LSRP, SD-4, and KORAS-G scores in a manner consistent with conceptual expectations. Also. the findings cross-culturally provide support for construct validity and incremental validity of the CAPP-SR in Korea as well as have clinical implications for the CAPP model more broadly, which are discussed.

A Study on Metaverse Utilization and Introduction Strategies in College Education: Based on Step-by-step Metaverse Introduction Framework (대학 교육의 메타버스 활용 현황 및 도입 전략에 대한 연구: 단계별 메타버스 도입 프레임워크 개발을 바탕으로)

  • Son, Young Jin;Park, Minjung;Chai, Sangmi
    • Knowledge Management Research
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    • v.24 no.1
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    • pp.1-29
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    • 2023
  • The COVID-19 pandemic has accelerated digital transformation across all industries and daily life. Edutech is spreading in the education field, also bringing changes in university education. Non-face-to-face online-only classes at universities have spread after the COVID-19 pandemic physical distancing started. Online-only or real-time online classes showed diverse educational imitations. 'Metaverse' started to attract attention as a learning space and community activity support platform that may solve the limitations of online education and communication. It is time to prepare an introduction strategy for the actual application of education using metaverse. This study, first, by examining previous studies and cases of metaverse application, and second, establishing a metaverse introduction framework based on the technology lifecycle model and the innovation diffusion theory. Finally, we provide an introduction strategy in steps, a specialized introduction plan according to the main users is established and presented as a scenario. We expect that this study will provide the theoretical background of the new technology introduction and the spread of metaverse research. Also, we present an efficient introduction strategy, the basis for a service model, and a practical basis for the university's value-added strategy.

A Study on the Intention to Use of the AI-related Educational Content Recommendation System in the University Library: Focusing on the Perceptions of University Students and Librarians (대학도서관 인공지능 관련 교육콘텐츠 추천 시스템 사용의도에 관한 연구 - 대학생과 사서의 인식을 중심으로 -)

  • Kim, Seonghun;Park, Sion;Parkk, Jiwon;Oh, Youjin
    • Journal of Korean Library and Information Science Society
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    • v.53 no.1
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    • pp.231-263
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    • 2022
  • The understanding and capability to utilize artificial intelligence (AI) incorporated technology has become a required basic skillset for the people living in today's information age, and various members of the university have also increasingly become aware of the need for AI education. Amidst such shifting societal demands, both domestic and international university libraries have recognized the users' need for educational content centered on AI, but a user-centered service that aims to provide personalized recommendations of digital AI educational content is yet to become available. It is critical while the demand for AI education amongst university students is progressively growing that university libraries acquire a clear understanding of user intention towards an AI educational content recommender system and the potential factors contributing to its success. This study intended to ascertain the factors affecting acceptance of such system, using the Extended Technology Acceptance Model with added variables - innovativeness, self-efficacy, social influence, system quality and task-technology fit - in addition to perceived usefulness, perceived ease of use, and intention to use. Quantitative research was conducted via online research surveys for university students, and quantitative research was conducted through written interviews of university librarians. Results show that all groups, regardless of gender, year, or major, have the intention to use the AI-related Educational Content Recommendation System, with the task suitability factor being the most dominant variant to affect use intention. University librarians have also expressed agreement about the necessity of the recommendation system, and presented budget and content quality issues as realistic restrictions of the aforementioned system.

Exploring Physical Activity Promotion Strategies for Older Residents in a Small Town Based on Socio-ecological Model: A Mixed Method Inquiry (사회생태학적 분석을 통한 중소규모 A 도시 거주 노인 신체활동 촉진전략 모색 - 혼합연구기법으로)

  • Kim, Kyung-O
    • 한국체육학회지인문사회과학편
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    • v.55 no.2
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    • pp.47-67
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    • 2016
  • The purpose of this study was to understand barriers and problems associated with physical activity of older adults in a small town and to provide improvement plans based on socio-ecological model. This study employed three independent phases including survey, accelerometer study, and photovoice. Three phases were analyzed based on nesting design among diverse mixed method designs. Among 134 older participants, 73 older individuals reported that their physical activity per week was less than 150min in the first phase. Among the 73 older individuals, 40 older individuals participated in the second phase. In the second phase, 32 older individuals does not meet at least 150min of moderate-to-vigorous physical activity(MVPA) suggested by DHHS. Finally, 6 older adults participated in the third phase. Five major themes emerged including 1) lack of proper information and service regarding physical activity, 2)lack of support from people close to them, 3)some limits due to chronic disease, 4)lack of appropriate facility, and 5)lack of opportunity due to existing inactive lifestyle. Based on these five themes, this study attempted to provide the improvement plans with socio-ecological model.