• Title/Summary/Keyword: 회귀현상

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Abnormal air temperature prediction of South Korea using multiple linear regression model and Terra/Aqua MODIS LST (다중 선형회귀모형과 Terra/Aqua MODIS 지표면온도를 활용한 우리나라 이상기온 예측)

  • Chung, Jeehun;Lee, Yonggwan;Lee, Jiwan;Kim, Seongjoon
    • Proceedings of the Korea Water Resources Association Conference
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    • 2019.05a
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    • pp.139-139
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    • 2019
  • 지구 온난화 및 기후변화로 인해 비롯된 전 지구적인 기온 상승은 가뭄, 폭염, 한파 등의 이상 기후 현상을 야기하여 인류의 생존을 위협하는 환경 문제로 대두되고 있다. 이와 같은 기후변화 및 이상기후 현상을 이해하고 파악하기 위해서는 정확하고 상세한 기온 정보가 필수적이다. 우리나라는 기상청에서 전국 590개소의 기상관측장비로 기온 정보를 생산하고 있지만 산림이 약 70%를 차지하는 복잡한 지형을 가지고 있어 지상관측밀도의 공간적 제약이 발생해 상세하고 균일한 기온 정보 생산에 제약이 있다. 이러한 단점을 극복하기 위해 본 연구에서는 위성으로 측정한 지표면 온도(Land Surface Temperature, LST) 자료와 다중선형회귀모형(Multiple Linear Regression Model)을 활용해 두 자료간의 상관관계를 파악하고 지상기온을 예측하고자 한다. 위성자료로 Terra 및 Aqua MODIS 위성의 1000m 공간해상도를 가진 일별 LST자료 MOD11A1, MYD11A1의 Daytime 자료를 각각 2000년부터 2018년까지 총 19년의 기간에 대해 구축하였으며, 전국 92개의 기상청 관측소로부터 최고, 최저 기온 자료를 동 기간에 대해 구축하였다. LST를 이용한 이상기온 예측 알고리즘은 python을 이용해 구현하였으며 예측 결과는 실제 기온 자료를 통해 검증하였다. 또한, 예측 기온 자료의 연대별, 순별(상, 중, 하순) 분석을 실시하고, 2018년 극한 폭염 및 한파(2017년 12월~2018년 2월)의 예측 가능성을 검토하여 연구 결과에 대한 다양한 활용방안을 제시하고자 한다.

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The Effect of Task-Oriented Mirror Therapy involve Visual Illusion on Upper Extremity Functions in Stroke Patients: Single Subject Study (착시현상이 반영된 과제지향적 거울치료가 뇌졸중 환자의 상지기능에 미치는 영향: 개별실험연구)

  • Choi, Seong-Youl;Kim, Su-Kyoung;Lee, Jae-Hong
    • The Journal of Korean society of community based occupational therapy
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    • v.3 no.2
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    • pp.13-23
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    • 2013
  • Objective : The purpose of this study is to evaluate the effect of task-oriented mirror therapy involve visual illusion on upper extremity functions in stroke patients. Method : We divided into two groups that task-oriented mirror therapeutic exercise program include visual illusion and not include. In order to determine the change in upper extremity function, Box & Block Test and Line-bisection Test was evaluated each time period. Result : The result of this study that we found out that all participation's upper extremity function had been improved during the intervention and sustained during baseline regression. Applying mirror therapy program include visual illusion group more improved trend line during the intervention, visual illusion group, it had been shown there are higher difference between visual illusion group and non-visual illusion group in upper extremity functions. Conclusion : It is thoughtful that task-oriented mirror therapy could help for stroke. It might be more effectiveness to apply who have exercise program include visual illusion.

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Spatial Analysis of the Urban Heat Island Using a 3-D City Model (3차원 도시모형을 이용한 도시열섬의 공간분석)

  • Chun, Bum-Seok;Guldmann, Jean-Michel
    • Spatial Information Research
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    • v.20 no.4
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    • pp.1-16
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    • 2012
  • There is no doubt that the urban heat island (UHI) is a mounting problem in built-up environments, due to energy retention by the surface materials of dense buildings, leading to increased temperatures, air pollution, and energy consumption. To investigate the UHI, three-dimensional (3-D) information is necessary to analyze complex sites, including dense building clusters. In this research, 3-D building geometry information is combined with two-dimensional (2-D) urban surface information to examine the relationship between urban characteristics and temperature. In addition, this research introduces spatial regression models to account for the spatial spillover effects of urban temperatures, and includes the following steps: (a) estimating urban temperatures, (b) developing a 3-D city model, (c) generating urban parameters, and (d) conducting statistical analyses using both Ordinary Least-Squares (OLS) and Spatial Regression Models. The results demonstrate that 3-D urban characteristics greatly affect temperatures and that neighborhood effects are critical in explaining temperature variations. Finally, the implications of the results are discussed, providing guidelines for policies to reduce the UHI.

A Zero-Inated Model for Insurance Data (제로팽창 모형을 이용한 보험데이터 분석)

  • Choi, Jong-Hoo;Ko, In-Mi;Cheon, Soo-Young
    • The Korean Journal of Applied Statistics
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    • v.24 no.3
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    • pp.485-494
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    • 2011
  • When the observations can take only the non-negative integer values, it is called the count data such as the numbers of car accidents, earthquakes, or insurance coverage. In general, the Poisson regression model has been used to model these count data; however, this model has a weakness in that it is restricted by the equality of the mean and the variance. On the other hand, the count data often tend to be too dispersed to allow the use of the Poisson model in practice because the variance of data is significantly larger than its mean due to heterogeneity within groups. When overdispersion is not taken into account, it is expected that the resulting parameter estimates or standard errors will be inefficient. Since coverage is the main issue for insurance, some accidents may not be covered by insurance, and the number covered by insurance may be zero. This paper considers the zero-inflated model for the count data including many zeros. The performance of this model has been investigated by using of real data with overdispersion and many zeros. The results indicate that the Zero-Inflated Negative Binomial Regression Model performs the best for model evaluation.

Demographic Change and Easing Shrinkage in Urban Centers of Metropolises (대도시 도심부의 인구변동과 쇠퇴 양상의 변화 - 도심쇠퇴의 이완과 도심회귀 증후의 검토 -)

  • Yim, Seokhoi
    • Journal of the Korean association of regional geographers
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    • v.22 no.3
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    • pp.599-614
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    • 2016
  • Urban centers have been recognized as problem regions so far. However, urban centers of metropolises take a new aspect in recent years as much as the negative influence of gentrification becomes a social issue. This paper analyzes the declining trend of urban centers in six metropolises - Seoul, Busan, Daegu, Incheon, Gwangju and Daejun from 1995 to 2010. As results of analysis, it is identified that the urban centers' shrinkage got moderated recently in the metropolises, even though their resurgence is not evident. Especially it is difficult to say longer that Jongro-Gu and Jung-Gu of Seoul are declining urban centers. Easing shrinkage is most outstanding in Jung-Gu, Daegu among local metropolises. Nevertheless, a serious obstacle such as high price of housing is in the process of obvious resurgence of urban center differently from the United States, Europe and Japan.

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Development of Return flow rate Prediction Algorithm with Data Variation based on LSTM (LSTM기반의 자료 변동성을 고려한 하천수 회귀수량 예측 알고리즘 개발연구)

  • Lee, Seung Yeon;Yoo, Hyung Ju;Lee, Seung Oh
    • Journal of Korean Society of Disaster and Security
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    • v.15 no.2
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    • pp.45-56
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    • 2022
  • The countermeasure for the shortage of water during dry season and drought period has not been considered with return flowrate in detail. In this study, the outflow of STP was predicted through a data-based machine learning model, LSTM. As the first step, outflow, inflow, precipitation and water elevation were utilized as input data, and the distribution of variance was additionally considered to improve the accuracy of the prediction. When considering the variability of the outflow data, the residual between the observed value and the distribution was assumed to be in the form of a complex trigonometric function and presented in the form of the optimal distribution of the outflow along with the theoretical probability distribution. It was apparently found that the degree of error was reduced when compared to the case not considering where the variance distribution. Therefore, it is expected that the outflow prediction model constructed in this study can be used as basic data for establishing an efficient river management system as more accurate prediction is possible.

Trip Generation Model Using Backpropagation Neural Networks in Comparison with linear/nonlinear Regression Analysis (신경망 이론을 이용한 통행발생 모형연구 (선형/비선형 회귀모형과의 비교))

  • 장수은;김대현;임강원
    • Journal of Korean Society of Transportation
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    • v.18 no.4
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    • pp.95-105
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    • 2000
  • The Purpose of this study is to present a new Trip Generation Model using Backpropagation Neural Networks. For this purpose, it is compared the performance between existing linear/nonlinear Regression models and a new TriP Generation model using Neural Networks. The study was performed according to the below. First, it is analyzed the limits of conventional Regression models, next Proved the superiority of Neural Networks model in theoretical and empirical aspects, and lastly Presented a new approach of Trip Generation methodology. The results show that Backpropagation Neural Networks model is predominant in estimation and Prediction comparable to Regression analysis. Such results mean the possibility of Neural Networks\` application in Trip Generation modeling. Specially under the circumstances of the chancing transportation situations and unstable transportation on vironments, its application in transportation fields will be extended.

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A comparison study of multiple linear quantile regression using non-crossing constraints (비교차 제약식을 이용한 다중 선형 분위수 회귀모형에 관한 비교연구)

  • Bang, Sungwan;Shin, Seung Jun
    • The Korean Journal of Applied Statistics
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    • v.29 no.5
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    • pp.773-786
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    • 2016
  • Multiple quantile regression that simultaneously estimate several conditional quantiles of response given covariates can provide a comprehensive information about the relationship between the response and covariates. Some quantile estimates can cross if conditional quantiles are separately estimated; however, this violates the definition of the quantile. To tackle this issue, multiple quantile regression with non-crossing constraints have been developed. In this paper, we carry out a comparison study on several popular methods for non-crossing multiple linear quantile regression to provide practical guidance on its application.

A Study on Forecasting of Overseas Tour - Gravity Model and Regression Model (해외관광 수요예측 모형에 관한 연구 제목 - 중력모형과 회귀모형)

  • Choi, Kyung-Ho;Kim, Jae-Hoon
    • Journal of the Korean Data and Information Science Society
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    • v.12 no.2
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    • pp.103-111
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    • 2001
  • Now a day, overseas tour which is due to economic development grows very much. In this situation, a forecast of overseas tour is required to establish tourism policy for tourism marketing. In this paper, we compare regression model and gravity model for a forecast of overseas tour. Using gravity model, this study also suggests an attraction which is suitable to our situation, and suggested attraction is compared and analyzed with another.

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Prediction of the Number of Food Poisoning Occurrences by Microbes (원인균별 식중독 발생 건수 예측)

  • Yeo, In-Kwon
    • The Korean Journal of Applied Statistics
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    • v.26 no.6
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    • pp.923-932
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    • 2013
  • This paper proposes a method to predict the number of foodborne disease outbreaks by microbes. The weekly data of food poisoning occurrences by microbes in Korea contain many zero-valued observations and have dependency between outbreaks. In order to model both phenomena, the number of food poisonings is predicted by an autoregressive model and the probabilities of food poisoning occurrences by microbes (given the total of food poisonings) are estimated by the baseline category logit model. The predicted number of foodborne disease outbreaks by a microbe is obtained by multiplying the predicted number of foodborne disease outbreaks and the estimated probability of the food poisoning by the corresponding microbe. The mean squared error and the mean absolute value error are evaluated to compare the performances of the proposed method and the zero-inflated model.