• 한국항행학회논문지
• /
• 제20권2호
• /
• pp.155-160
• /
• 2016

최근에 수중 음향통신에 대한 연구가 많은 연구자들에 의해 연구되어왔다. 수중 환경 UWAC를 사용하기 위해서는 두 신호들 사이의 시간차이를 추정하는 것이 필요하다. 일반적으로 두 신호 시아의 시간차이를 추정하는 기법으로는 배경 영역이 없는 시간을 추정하여 시간 차이를 추정하는 기법, 시간을 추정하여 두 신호 사이의 상호 상관을 추정하는 기법, 시간 차이 추정을 위한 위상지연을 추정하는 기법이 주로 사용된다. 본 논문에서는 UWAC에 적용하기 위하여 시간 지연 추정에 의한 두 신호 사이의 상호상관을 계산하고 이 상호 상관을 이용한 도착 시간의 추정 결과를 0.003055 초가 됨을 보인다.

• 대기
• /
• 제26권4호
• /
• pp.711-716
• /
• 2016

The dynamical model forecasts using state-of-art general circulation models (GCMs) have some limitations to simulate the real climate system since they do not depend on the past history. One of the alternative methods to correct model errors is to use the canonical correlation analysis (CCA) correction method. CCA forecasts at the present time show better skill than dynamical model forecasts especially over the midlatitudes. Model outputs are adjusted based on the CCA modes between the model forecasts and the observations. This study builds a canonical correlation prediction model for subseasonal (June) precipitation. The predictors are circulation fields over western North Pacific from the Global Seasonal Forecasting System version 5 (GloSea5) and observed snow cover extent over Eurasia continent from Climate Data Record (CDR). The former is based on simultaneous teleconnection between the western North Pacific and the East Asia, and the latter on lagged teleconnection between the Eurasia continent and the East Asia. In addition, we suggest a technique for improving forecast skill by applying the ensemble canonical correlation (ECC) to individual canonical correlation predictions.

• 산업경영시스템학회지
• /
• 제8권11호
• /
• pp.27-34
• /
• 1985

Recently the distributed lag models for time series data have been used in several quantitative analyses. But the analyses of time series which have the serial correlations in error terms and the lagged values of dependent variables violate the hypothesis of OLS method. This paper suggests that the approach technique of distributed lay model with serial correlation should be applied by the Bayesian inference to estimate the parameters. For the application of distributed lag model by Bayesian analysis, the data for monthly consumption expenditure per household by items of commodities from 1972 to 1981 are used in order to estimate the lagged coefficient of processed food and the regression coefficient of the food and beverage.

• 한국컴퓨터정보학회논문지
• /
• 제27권9호
• /
• pp.177-190
• /
• 2022

본 연구에서는 장애인고용패널 2차웨이브 1차년도(2016년)부터 6차년도(2021년)까지 데이터를 활용하여 20세 이상 성인 임금 장애근로자의 장애수용과 직무만족도 사이의 종단적 변화양상과 상호적 인과관계를 분석하기 위해 자기회귀교차지연 모형을 적용하였다. 분석결과, 첫째, 장애 임금근로자의 이전 시점의 장애수용과 직무만족도는 각각 이후 시점의 장애수용(𝛽=.556~.610)과 직무만족도(𝛽=.554~.585)에 안정적으로 유의한 영향을 미치는 것으로 나타났다. 둘째, 장애 임금근로자의 이전 시점의 장애수용은 이후 시점의 직무만족도(𝛽=.077~.090)에 그리고 이전 시점의 직무만족도는 이후 시점의 장애수용(𝛽=.087~.092)에 교차지연효과가 유의한 것으로 나타났다. 셋째, 장애 임금근로자의 성별 집단에 따른 모형적합도 분석결과 시간의 흐름에 따른 장애수용과 직무만족도 사이의 자기회귀효과 및 장애수용과 직무만족도 사이의 교차지연효과의 차이가 유의하지 않게 나타났다.

• 한국전자통신학회논문지
• /
• 제11권4호
• /
• pp.365-372
• /
• 2016

최근에 UWAC에 대한 연구가 많은 연구자와 학자들에 의해 연구되고 있다. 수중 환경에서 두 신호 사이의 시간 차이 추정 기법은 배경이 없는 영역에서 도착 시간 추정, 상관관계 추정, 그리고 시간 지연 추정의 3가지가 제시되어 있다. 이 논문에서는 위상 지연에 기반하여 두 신호 사이에서의 시간 차이 추정 기법을 제시한다.

• 디지털융복합연구
• /
• 제19권10호
• /
• pp.453-467
• /
• 2021

본 연구에서는 어머니의 문화적응 유형, 다문화청소년의 다문화수용성, 국가정체성이 시간의 흐름에 따른 변화 양상과 세 요인 간의 종단적 상호관련성을 검증하고자 자기회귀교차지연모형을 적용하였다. 연구를 위해 MAPS의 자료 중 초등학교 5학년부터 고등학교 2학년까지 추적한 2차-4차-6차-8차년도 시점의 종단자료를 활용하여 분석하였다. 분석결과, 어머니의 문화적응 4가지 유형 모두는 시간의 지남에 따라 유의한 종단적 영향을 미치는 것으로 분석되었다. 어머니의 문화적응 4가지 유형은 다문화청소년의 국가정체성 간의 관계에서 다문화수용성은 종단적 매개효과를 갖는 것으로 분석되었다. 이러한 분석결과를 토대로 다문화청소년이 다문화적 가치를 수용하고 이를 확장해 이중문화스트레스를 극복하고 국가에 대한 소속감과 연대감을 갖는데 다문화수용성을 높이는 교육도 병행되어야 함을 제안하였다.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2015년도 학술발표회
• /
• pp.224-224
• /
• 2015

The East Asia monsoon is one of the most complex atmospheric phenomena caused by Land-Sea thermal contrast. It plays essential role in fulfilling the water needs of the region but also poses stern consequences in terms of flooding and droughts. This study analyzed the influence of Global Sea Surface Temperature Anomalies (SSTA) on occurrence of droughts in the East Asia monsoon region ($20^{\circ}N-50^{\circ}N$, $103^{\circ}E-149^{\circ}E$). Standardized Precipitation Index (SPI) was employed to characterize the droughts over the region using 30-year (1978-2007) gridded rainfall dataset at $0.5^{\circ}$ grid resolution. Due to high variability in intensity and spatial extent of monsoon rainfall the East Asia monsoon region was divided into the homogeneous rainfall zones using cluster analysis method. Seven zones were delineated that showed unique rainfall regimes over the region. The influence of SSTA was assessed by using lagged-correlation between global gridded SSTA ($0.2^{\circ}$ grid resolution) and SPI of each zone. Sea regions with potential influence on droughts in different zones were identified based on significant positive and negative correlation between SSTA and SPI with a lag period of 3-month. The results showed that SSTA have the potential to be used as predictor variables for prediction of droughts with a reasonable lead time. The findings of this study will assist to improve the drought prediction over the region.

• International Journal of Contents
• /
• 제15권4호
• /
• pp.113-119
• /
• 2019

It has been reported that large amounts of information on agri-foods were delivered to consumers through television and social networks, and the information may influence consumers' behavior. The purpose of this paper was first to analyze relations of social network service and broadcasting program on paprika consumption in the aspect of amounts to purchase and identify potential factors that can promote paprika consumption; second, to develop prediction models of paprika consumption by using structured and unstructured big data. By using data 2010-2017, cross-correlation and time-series prediction algorithms (autoregressive exogenous model and vector error correction model), statistically significant correlations between paprika consumption and television programs/shows and blogs mentioning paprika and diet were identified with lagged times. When paprika and diet related data were added for prediction, these data improved the model predictability. This is the first report to predict paprika consumption by using structured and unstructured data.

• The Journal of Asian Finance, Economics and Business
• /
• 제9권6호
• /
• pp.331-341
• /
• 2022

Through emotional exhaustion, this study empirically tests followers' behavioral responses to autocratic leaders. The current research focuses on effects caused by despotic leadership on followers' emotional exhaustion, which leads to employee outcomes such as interpersonal deviances and indirect aggression. The association between despotic leadership and results (employee interpersonal deviance and indirect violence) is investigated in this study. In this study, emotional exhaustion is used as a mediator. Furthermore, negative affectivity is used as a moderator between despotic leadership and emotional exhaustion. A time-lagged framework is employed with a sample of 255 respondents. Age, qualification, marital status, gender, grade, type of organization, department, and job experience are among the eight demographical questions in this study. After evaluating the data for normality, correlation analysis was performed, followed by moderation and mediation analysis. The current study explores the link between despotic leadership and emotional exhaustion among followers, arguing that a despotic leader will leave followers exhausted at work. Emotional exhaustion was also linked to interpersonal deviances, such as indirect aggression, in a significant and positive way. Employee outcomes, such as interpersonal deviances and indirect aggressiveness through emotional exhaustion, will be influenced by a despotic leader, according to the findings.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2023년도 학술발표회
• /
• pp.249-249
• /
• 2023

Spring drought forecasting in South Korea is essential due to the sknewness of rainfall which could lead to water shortage especially in spring when managed without prediction. Therefore, drought forecasting over South Korea was performed in the current study by thoroughly searching appropriate predictors from the lagged global climate variable, mean sea level pressure(MSLP), specifically in winter season for forecasting time lag. The target predictand defined as accumulated spring precipitation(ASP) was driven by the median of 93 weather stations in South Korea. Then, it was found that a number of points of the MSLP data were significantly cross-correlated with the ASP, and the points with high correlation were regionally grouped. The grouped variables with three regions: the Arctic Ocean (R1), South Pacific (R2), and South Africa (R3) were determined. The generalized linear model(GLM) was further applied for skewed marginal distribution in drought prediction. It was shown that the applied GLM presents reasonable performance in forecasting ASP. The results concluded that the presented regionalization of the climate variable, MSLP can be a good alternative in forecasting spring drought.