• Title/Summary/Keyword: Stepwise Regression Method

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A Prediction Method Combining Clustering Method and Stepwise Regression (군집분석 기법과 단계별 회귀모델을 결합한 예측 방법)

  • Chong Il-gyo;Jun Chi-Hyuck
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2002.05a
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    • pp.949-952
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    • 2002
  • A regression model is used in predicting the response variable given predictor variables However, in case of large number of predictor variables, a regression model has some problems such as multicollinearity, interpretation of the functional relationship between the response and predictors and prediction accuracy. A clustering method and stepwise regression could be used to reduce the amount of data by grouping predictors having similar properties and by selecting the subset of predictors. respectively. This paper proposes a prediction method combining clustering method and stepwise regression. The proposed method fits a global model and local models and predicts responses given new observations by using both models. The paper also compares the performance of proposed method with stepwise regression via a real data of ample obtained in a steel process.

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Quantitative Analysis by Diffuse Reflectance Infrared Fourier Transform and Linear Stepwise Multiple Regression Analysis I -Simultaneous quantitation of ethenzamide, isopropylantipyrine, caffeine, and allylisopropylacetylurea in tablet by DRIFT and linear stepwise multiple regression analysis-

  • Park, Man-Ki;Yoon, Hye-Ran;Kim, Kyoung-Ho;Cho, Jung-Hwan
    • Archives of Pharmacal Research
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    • v.11 no.2
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    • pp.99-113
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    • 1988
  • Quantitation of ethenzamide, isopropylantipyrine and caffeine takes about 41 hrs by conventional GC method. Quantitation of allylisoprorylacetylurea takes about 40 hrs by conventional UV method. But quantitation of them takes about 6 hrs by DRIFT developing method. Each standard and sample sieved, powdered and acquired DRIFT spectrum. Out of them peak of each component was selected and ratio of each peak to standard peak was acquired, and then linear stepwise multiple regression was performed with these data and concentration. Reflectance value, Kubelka-Munk equation and Inverse-Kubelka-Munk equation were modified by us. Inverse-Kubelka-Munk equation completed the deficit of Kubelka-Munk equation. Correlation coefficients acquired by conventioanl GC and UV against DRIFT were more than 0.95.

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Analysis of Client Propensity in Cyber Counseling Using Bayesian Variable Selection

  • Pi, Su-Young
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.6 no.4
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    • pp.277-281
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    • 2006
  • Cyber counseling, one of the most compatible type of consultation for the information society, enables people to reveal their mental agonies and private problems anonymously, since it does not require face-to-face interview between a counsellor and a client. However, there are few cyber counseling centers which provide high quality and trustworthy service, although the number of cyber counseling center has highly increased. Therefore, this paper is intended to enable an appropriate consultation for each client by analyzing client propensity using Bayesian variable selection. Bayesian variable selection is superior to stepwise regression analysis method in finding out a regression model. Stepwise regression analysis method, which has been generally used to analyze individual propensity in linear regression model, is not efficient since it is hard to select a proper model for its own defects. In this paper, based on the case database of current cyber counseling centers in the web, we will analyze clients' propensities using Bayesian variable selection to enable individually target counseling and to activate cyber counseling programs.

Validation of Nursing Care Sensitive Outcomes related to Knowledge (지식에 관한 간호결과도구의 타당성 조사)

  • 이은주
    • Journal of Korean Academy of Nursing
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    • v.33 no.5
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    • pp.625-632
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    • 2003
  • Purpose: The purpose of this study was to assess the importance and sensitivity to nursing interventions of four nursing sensitive nursing outcomes selected from the Nursing Outcomes Classification (NOC). Outcomes for this study were 'Knowledge: Diet', 'Knowledge: Disease Process', 'Knowledge: Energy Conservation', and 'Knowledge: Health Behaviors'. Method: Data were collected from 183 nurses working in 2 university hospitals. Fehring method was used to estimate outcome and indicators' content and sensitivity validity. Multiple and stepwise regression were used to evaluate relationships between each outcome and its indicators. Result: Results confirmed the importance and nursing sensitivity of outcomes and their indicators. Key indicators of each outcomes were found by multiple regression. 'Knowledge: Diet' was suggested for adding new indicators because the variance explained by indicators was relatively low. Not all of the indicators selected for stepwise regression model were rated for highly in Fehring method. The R² statistics of the stepwise regression models were between 18 and 63% in importance by selected indicators and between 34 and 68% in contribution by selected indicators. Conclusion: This study refined what outcomes and indicators will be useful in clinical practice. Further research will be required for the revision of outcome and indicators of NOC. However, this study refined what outcomes and indicators will be useful in clinical practice.

A Climate Prediction Method Based on EMD and Ensemble Prediction Technique

  • Bi, Shuoben;Bi, Shengjie;Chen, Xuan;Ji, Han;Lu, Ying
    • Asia-Pacific Journal of Atmospheric Sciences
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    • v.54 no.4
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    • pp.611-622
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    • 2018
  • Observed climate data are processed under the assumption that their time series are stationary, as in multi-step temperature and precipitation prediction, which usually leads to low prediction accuracy. If a climate system model is based on a single prediction model, the prediction results contain significant uncertainty. In order to overcome this drawback, this study uses a method that integrates ensemble prediction and a stepwise regression model based on a mean-valued generation function. In addition, it utilizes empirical mode decomposition (EMD), which is a new method of handling time series. First, a non-stationary time series is decomposed into a series of intrinsic mode functions (IMFs), which are stationary and multi-scale. Then, a different prediction model is constructed for each component of the IMF using numerical ensemble prediction combined with stepwise regression analysis. Finally, the results are fit to a linear regression model, and a short-term climate prediction system is established using the Visual Studio development platform. The model is validated using temperature data from February 1957 to 2005 from 88 weather stations in Guangxi, China. The results show that compared to single-model prediction methods, the EMD and ensemble prediction model is more effective for forecasting climate change and abrupt climate shifts when using historical data for multi-step prediction.

Relationship between Aiming Patterns and Scores in Archery Shooting

  • Quan, ChengHao;Lee, Sangmin
    • Korean Journal of Applied Biomechanics
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    • v.26 no.4
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    • pp.353-360
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    • 2016
  • Objective: The aim of this study was to investigate the relationship between aiming patterns and scores in archery shooting. Method: Four (N = 4) elementary-level archers from middle school participated in this study. Aiming pattern was defined by averaged acceleration data measured from accelerometers attached on the body during the aiming phase in archery shooting. Stepwise multiple regression analysis was used to test whether a model incorporating aiming patterns from all nine accelerometers could predict the scores. In order to extract period of interest (POI) data from raw data, a Dynamic Time Warping (DTW)-based extraction method was presented. Results: Regression models for all four subjects are conducted with different significance levels and variables. The significance levels of the regression models are 0.12%, 1.61%, 0.55%, and 0.4% respectively; the $R^2$ of the regression models is 64.04%, 27.93%, 72.02%, and 45.62% respectively; and the maximum significance levels of parameters in the regression models are 1.26%, 4.58%, 5.1%, and 4.98% respectively. Conclusion: Our results indicated that the relationship between aiming patterns and scores was described by a regression model. Analysis of the significance levels, variables, and parameters of the regression model showed that our approach - regression analysis with DTW - is an effective way to raise scores in archery shooting.

Validation of the Nursing Outcomes Classification on Cerebrovascular Patients (뇌혈관질환자에게 적용가능한 간호결과 분류체계의 타당성 검증)

  • Kim, Young-Hwa;So, Hyang-Sook;Lee, Eun-Joo;Ko, Eun
    • Korean Journal of Adult Nursing
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    • v.20 no.3
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    • pp.489-499
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    • 2008
  • Purpose: The purpose of this study was to assess the importance and contribution of 9 nursing outcomes and their indicators that could be applied to cerebrovascular patients. Methods: Data were collected from 175 neurosurgical nurses working at two university affiliated hospitals and five secondary hospitals located in Gwang-ju. The Fehring method was used to estimate outcome content validity(OCV) and outcome sensitivity validity(OSV) of nursing outcomes and their indicators. Stepwise regression was used to evaluate relationship between outcome and its indicators. Results: The core outcomes identified by the OCV were Tissue Perfusion: Cerebral, Nutritional Status, Neurological Status, and Wound Healing: Primary Intention, whereas highly supportive outcomes identified by the OSV were Oral Health, Self-Care: ADL, and Nutritional Status. All the critical indicators selected for Fehring method were not included in stepwise regression model. By stepwise regression analysis, the indicators explained outcomes from 19% to 52% in importance and from 21% to 45% in contribution. Conclusion: This study identified core and supportive outcomes and their indicators which could be useful to assess the physical status of cerebrovascular patients. Further research is needed for the revision and development of nursing outcomes and their indicators at neurological nursing area.

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Evaluation of Sigumjang Aroma by Stepwise Multiple Regression Analysis of Gas Chromatographic Profiles

  • Choi, Ung-Kyu;Kwon, O-Jun;Lee, Eun-Jeong;Son, Dong-Hwa;Cho, Young-Je;Im, Moo-Hyeog;Chung, Yung-Gun
    • Journal of Microbiology and Biotechnology
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    • v.10 no.4
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    • pp.476-481
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    • 2000
  • A linear correlation, by the stepwise multiple regression analysis, was found between the sensory test of Sigumjang aroma and the gas chromatographic data which were transformed with logarithm. GC data is the most objective method to evaluate Sigumjang aroma. A multiple correlation coefficient and a determination coefficient of more than 0.9 were obtained at the 9th and 13th steps, respectively. At step 31, the coefficient of determination level of 0.95 was attained. The accuracy of its estimation became higher as the number of the variables entered into the regression model increased. Over 90% of the Sigumjang aroma was explained by 13 compounds indentified on GC. The contributing proportion of the peak 26 was the highest followed by peaks 57 (9.27%), 29 (7.51%), 54 (6.01%), 8 (5.99%), 49 (4.97%), and 13 (4.11%).

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Study on the Critical Storm Duration Decision of the Rivers Basin (중소하천유역의 임계지속시간 결정에 관한 연구)

  • Ahn, Seung-Seop;Lee, Hyeo-Jung;Jung, Do-June
    • Journal of Environmental Science International
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    • v.16 no.11
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    • pp.1301-1312
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    • 2007
  • The objective of this study is to propose a critical storm duration forecasting model on storm runoff in small river basin. The critical storm duration data of 582 sub-basin which introduced disaster impact assessment report on the National Emergency Management Agency during the period from 2004 to 2007 were collected, analyzed and studied. The stepwise multiple regression method are used to establish critical storm duration forecasting models(Linear and exponential type). The results of multiple regression analysis discriminated the linear type more than exponential type. The results of multiple linear regression analysis between the critical storm duration and 5 basin characteristics parameters such as basin area, main stream length, average slope of main stream, shape factor and CN showed more than 0.75 of correlation in terms of the multi correlation coefficient.

A study on equating method based on regression analysis (회귀분석에 기초한 균등화 방법에 관한 연구)

  • Cho, Jang-Sik
    • Journal of the Korean Data and Information Science Society
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    • v.21 no.3
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    • pp.513-521
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    • 2010
  • Most of universities have carried out course evaluation to apply the performance appraisal for professor. But, course evaluation depends on characteristics of each class such as class size, type of lecture, evaluator's grade and so on. As the results, such characteristics of each class lead to serious bias which makes lecturers distrust the course evaluation results. Hence, we propose a equating method for the course evaluation by regression analysis which use stepwise variable selection. And we compare proposed method with the other method by Cho et al. (2009) with respect to efficiencies. Also we give the example to which the method is applied.