• The Korean Journal of Applied Statistics
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• v.26 no.6
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• pp.915-922
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• 2013

Quantile regression can estimate multiple conditional quantile functions of the response, and as a result, it provide comprehensive information of the relationship between the response and the predictors. However, when estimating several conditional quantile functions separately, two or more estimated quantile functions may cross or overlap and consequently violate the basic properties of quantiles. In this paper, we propose a new stepwise method to estimate multiple non-crossing quantile functions using constraints on the kernel coefficients. A simulation study are presented to demonstrate satisfactory performance of the proposed method.

• Research in Community and Public Health Nursing
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• v.13 no.3
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• pp.523-531
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• 2002

Purpose: The purpose of this study was to assess the importance and sensitivity to nursing interventions of six sensitive nursing outcomes selected from the Nursing Outcomes Classification. The outcomes in this study were Self-Care: Activities of Daily Living, Self-Care: Instrumental Activities of Daily Living, Treatment Behavior: Illness or Injury, Knowledge: Health Promotion, Caregiver Performance: Direct Care, and Caregiver Physical Health. Method: Data were collected from 97 visiting nurses working in public health centers located in a province and a capital city. The Fehring method was used to estimate outcomes and indicators for content validity. Simultaneous multiple regression and stepwise regression were used to evaluate relationships between each outcome and its indicators. Results: Results confirmed the importance and nursing sensitivity of the outcomes and their indicators. Multiple regression revealed key indicators of each outcome. Self-Care: Instrumental Activity of Daily Living needed to be revised. Neither all of the indicators nor the indicators showing the highest importance and contribution ratio were selected as independent variables for the stepwise regression model. The R2 of the regression models ranged from 29 to 56% in importance by selected indicators and from 56 to 83% in contribution. Conclusion: Further research is needed for the revision of outcomes and their indicators.

• 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.

• The Korean Journal of Applied Statistics
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• v.11 no.2
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• pp.435-449
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• 1998

In this article we have introduced a Bayes criterion for the variable selection in multiple discriminant analysis (MDA). The criterion is a default Bayes factor for the comparision of homo/heteroscadasticity of the multivariate normal means. The default Bayes factor is obtained from a development of the imaginary training sample method introduced by Spiegelhalter and Smith (1982). Based an the criterion, we also provided a test for additional discrimination in MDA. The advantage of the criterion is that it is not only applicable for the optimal subset selection method but for the stepwise method. More over, the criterion can be reduced to that for two-group discriminant analysis. Thus the criterion can be regarded as an unified alternative to variable selection criteria suggested by various sampling theory approaches. To illustrate the performance of the criterion, a numerical study has bean done via Monte Carlo experiment.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.2
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• pp.191-200
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• 2000

Objective: This study was carried out to compare the effects of the stepwise exposure treatments on the morphological normality, fertilization and blastocyst formation rate of the frozen-thawed mouse mature oocytes by vitrification or ultra-rapid freezing and to use as a fundamental data for the cryopreservation of human oocytes. Materials and Methods: The morphological normality and fertilization rates of the vitrified and ultra-rapid frozen mouse mature oocytes after three-stepwise exposure treatments (1step, 3step and 5step) were observed. After choosing the 3step exposure treatment groups, we observed the morphological normality and fertilization, blastocyst formation rate of the vitrified and ultra-rapid frozen mouse mature oocytes. Results: The morphological normality and fertilization rates of the vitrified mouse mature oocytes after three-stepwise exposure treatments (1step, 3step and 5step) were 75%, 85%, 88% and 58%, 61 %, 54% respectively. There were no significant differences among treatments(p>0.05). The morphological normality and fertilization rate of the control was 92% and 65%. There were no significant differences in fertilization rate among control and treatments (p>0.05). The morphological normality and fertilization rates of the ultra-rapid frozen mouse mature oocytes after three-stepwise exposure treatments (1step, 3step and 5step) were 83%, 83%, 84% and 75%, 63%, 56% respectively. There were no significant differences among treatments (p>0.05). The morphological normality and fertilization rate of the control was 95% and 67%. There were no significant differences among control and treatments (p>0.05). The morphological normality and fertilization rate of the vitrified or ultra-rapid frozen mouse mature oocytes after 3step exposure treatment were 69% and 75%, respectively. The blastocyst formation rate was 60% and 57%. The results did not differ significantly between vitrification and ultra-rapid freezing (p>0.05). Conclusion: As known in the above results, there were no significant differences in the fertilization and blastocyst formation rate of the frozen-thawed mouse mature oocytes by vitrification or ultra-rapid freezing among the control and treatments. It is suggested that vitrification and ultra-rapid freezing method were effective for the cryopreservation of mouse mature oocytes.

• Journal of Broadcast Engineering
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• v.21 no.3
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• pp.425-435
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• 2016

In this paper, we propose a classification model by analyzing raw material images recorded using a color CCD camera to automatically classify good and defective agricultural products such as rice, coffee, and green tea, and raw materials. The current classifying agricultural products mainly depends on visual selection by skilled laborers. However, classification ability may drop owing to repeated labor for a long period of time. To resolve the problems of existing human dependant commercial products, we propose a vision based automatic raw material classification combining mean shift clustering and stepwise region merging algorithm. In this paper, the image is divided into N cluster regions by applying the mean-shift clustering algorithm to the foreground map image. Second, the representative regions among the N cluster regions are selected and stepwise region-merging method is applied to integrate similar cluster regions by comparing both color and positional proximity to neighboring regions. The merged raw material objects thereby are expressed in a 2D color distribution of RG, GB, and BR. Third, a threshold is used to detect good and defective products based on color distribution ellipse for merged material objects. From the results of carrying out an experiment with diverse raw material images using the proposed method, less artificial manipulation by the user is required compared to existing clustering and commercial methods, and classification accuracy on raw materials is improved.

• The Korean Journal of Applied Statistics
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• v.10 no.1
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• pp.137-149
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• 1997

In this paper we propose a logdensity estimation based on a Fourier expansion. The basis functions consisting of trigonometric functions are determinded by stepwise addition and deletion and the Bayes Information Criterion, where the maximum likelihood method is used to estimate the parameters. Numericla examples using real data and simulated data are provided to show the performance of proposed method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.9
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• pp.1448-1455
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• 1990

In this paper, a range image segmentation method is proposed. This method consists of an initial segmentation stage by discontinuous edge detection and surface type labeling based on the sign of the principal curvatures. Initially type labeled image is oversegmented, this image is merged via stepwise optimal region merging stage based on polynomial function approxiamtion. The successful segmentation results are presented for two synthetic range images with noise and a real-world ERIM range image.

• Explosives and Blasting
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• v.25 no.1
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• pp.31-43
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• 2007

In most tunnel constructions in South Korea, blasting has been widely used as an excavation method. In tunnel blasting, the center-cut to induce first free surface is very important for enhancing excavation efficiency and reducing vibration caused by exploding. This paper introduces new center-cut method named SAV-cut (Stage Advance V-cut) developed on the concept of V-cut. Significant features of SAV-cut are the center hole and stepwise ignition. Many field tests and numerical analysis were carried out to analyze the mechanical behavior and blasting vibration. From the results, the newly developed SAV-cut was proved as an effective center-cut method for both increasing blasting efficiency and decreasing blasting vibration.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.4
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• pp.53-60
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• 2009

Recently, the Korean government has amended the "National Territory Planning Act" by adding criteria to designate the Impact Fee Zone on the basis of the population increase rate. Taking the Dongtan Newtown in Hwasung City as the case, the study first tries to apply a grid analysis method to figure out the cells that exceed the legal population increase rate criteria. Then, the study, for rather a practical purpose, introduces a scenario analysis that tries to envelope the cells into a spatially contiguous groups based on their degrees of stepwise adjacency by cell buffer formation. By overlapping the selected cell groups chosen by such stepwise scenarios over the actual zoning map of land-uses for the vicinity, it seems clear that the chosen areas rationally coincide with those residential blocks and commercial areas with the high population density in the Newtown.