• Proceedings of the Korean Society for Quality Management Conference
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• 2006.04a
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• pp.330-333
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• 2006

Many practical problems of quality control in service management are derived from the use of ordinal variables. Ordered linguistic variables differ from measurement variables. This paper presents a new control chart of a production process based on ordinal variables.

• Journal of the Korea Society for Simulation
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• v.21 no.3
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• pp.71-78
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• 2012

This research discusses the application of the control variables to achieve a more precise estimation for the target response in queueing network simulation. The efficiency of control variable method in estimating the response depends upon how we choose a set of control variables strongly correlated with the response and how we construct a function of selected control variables. For a class of queuing network simulations, the random variables that drive the simulation are basically the service-time and routing probability random variables. Most of applications of control variable method focus on utilization of the service time random variables for constructing a controlled estimator. This research attempts to suggest a controlled estimator which uses these two kinds of random variables and explore the efficiency of these estimators in estimating the reponses for computer network system. Simulation experiments on this model show the promising results for application of routing probability control variables. We consider the applications of the routing probability control variables to various simulation models and combined control variables using information of service time and routing probability together in constructing a control variable as future researches.

• Journal of Families and Better Life
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• v.25 no.3 s.87
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• pp.77-87
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• 2007

This study purports to understand the direct and indirect effects between eating disorder behavior of female adolescents and their body-related variables(concerning the degree of diet regime, weight control, body satisfaction, and obesity), self-esteem and internal control, by checking three sub-categorized behavior of eating disorders of diet behavior, bulimia behavior, and eating control behavior. The sample group used for the study consisted of 190 female high school students and 292 female university students; measurement devices used for the study were those of body-related variables, self esteem and internal control, and eating disorder behavior; and data analysis was performed using ${\chi}2$, t-test, Pearson's correlation, regression analysis and path analysis. The results are as follows. First, there is a significant difference between university students and high school students regarding their body satisfaction, weight control experience, and self esteem. University students are more satisfied with their body, have higher self esteem, and control their weight better than high school students. Second, diet behavior shows a correlation with the degree of diet interest, weight control experience, and body satisfaction. Body satisfaction and internal control proved to be correlated with bulimia behavior, while weight control experience, obesity, and self esteem were correlated with eating control behavior. Third, the variables that showed a direct influence on diet behavior as an eating disorder are diet interest, weight control experience, body satisfaction and obesity, in that the explanatory power of the variables is 60.7% with the highest mark on obesity. The variables that showed effects on bulimia are body satisfaction and internal control with an explanatory power of 2.8%. Indirect variables effecting bulimia include objects, diet interest, body satisfaction, and self esteem. The variable with a direct influence on eating control behavior was self esteem with and explanatory power of 4%, whereas the variables of objects, diet interest, body satisfaction, weight control experience, and internal control were all indirectly correlated with eating control behavior.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.60.4-60
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• 2002

Nonlinear adaptive control for the laboratory pressure-flow model. Control valves are installed on both sides. The pressure and the outlet flow rate are measured. The pressure and outlet flow rate are controlled variables and the control valve stem positions on both sides are the manipulated variables. The variation in both inputs will influence both controlled variables. The control performance is good, in spite of varying valve coefficients of inlet and outlet.

• Journal of The Korean Association For Science Education
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• v.31 no.1
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• pp.32-47
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• 2011

The purpose of this study was to analyze the ability to control variables and the ways by which variables are controlled. First, the assessment criteria for evaluating the students' ability to control variables were developed for 8th grade students. Second, the ways variables are controlled were classified from student activity reports. These students' answers were categorized into six types (type A~ type F). Type A is defined as the group that excelled in recognizing the importance of controlling variables, eliminating unnecessary variables and identifying manipulated, dependent and controlled variables. Third, the scores of ability to control variables (CV score) and the classroom test of scientific reasoning (Lawson SRT) scores were measured. The results indicated that the CV score was highly correlated with Lawson SRT scores (r=.67, p<.01). Therefore, the assessment criteria developed in this study was used to evaluate the ability to control variables (CV score) and to measure the students' scientific reasoning.

• Journal of KSNVE
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• v.8 no.2
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• pp.283-288
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• 1998

If one wants to control the noise from a duct, then one must have sufficient number of sensors and actuators so that the control system is observable and controllable. A number of sensors and actuators for control of radiating noise from a duct have to be incorporated with the number of modes which one wants to control. These considerations motivated the present study that considers a control system which has less microphones and actuators than required. In this work, by theoretical analysis and numerical simulation, the control performance and robust reliability of such a kind of control system is investigated in terms of sound-field variables and control system variables. Then the possibility of implementation of the robust radiation power control system is verified by theoretical analysis and numerical simulation. In addition, the control performance of the control system is verified by experiment.

• Journal of the Korean Data and Information Science Society
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• v.28 no.4
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• pp.937-945
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• 2017

The purpose of using a control chart is to detect any change that occurs in the process. When control charts are used to monitor processes, we want to identify this changes as quickly as possible. Many problems in quality control involve a vector of observations of several characteristics rather than a single characteristic. Multivariate CUSUM or EWMA charts have been developed to address the problem of monitoring covariance matrix or the joint monitoring of mean vector and covariance matrix. However, control charts tend to work poorly when we use the highly correlatted variables. In order to overcome it, Hawkins (1991) proposed the use of regression adjustment variables. In this paper, to monitor covariance matrix, we investigate the performance of MEWMA-type control charts with and without the use of regression adjusted variables.

• Korean Journal of Human Ecology
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• v.13 no.6
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• pp.833-845
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• 2004

This study examines different individual and environmental factors that affect children's self-control. For an analysis, locus of control, perceived competence, and achievement motivation were all included in individual variables. For family variables, mothers' parenting and patents' marriage conflict were examined. For classroom psycho-social environment, teacher support, peer relationship, class involvement, and teachers' supervision were used. The sample consisted of 548 fifth and sixth grade children. Statistics and methods used for the data analysis were Cronbach's alpha, frequency, percentage, Pearson's correlation, and Hierarchical Regression. Several major results were found from the analysis: First, locus of control, perceived competence, and achievement motivation had a positive correlation with children's self-control. Second, mothers' affective parenting had a positive correlation with children's self-control. However, mothers' controlling parenting and parents' marriage conflict had a negative correlation with it. Third, teacher support, peer relationship, and class involvement had a positive correlation with children's self-control. In addition, teacher supervision had a positive correlation with girls' self-control. Fourth, class involvement, locus of control, and academic competence were important variables predicting boys' self-control. On the other hand, Class involvement, achievement motivation, academic competence, teacher's supervision, and mothers' controlling parenting were important variables predicting girl's self-control.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.519-528
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• 2011

The main purpose of this study was to develop a teaching program, especially designed to improve the skills of control variables. The secondary purpose was to investigate the effect of the program on enhancing students' scientific reasoning and understanding. The program was designed based on the 3-step learning model: i.e. students recognize the necessity of controlling the variables (step 1), perform their own experiments (step 2), and reflect on their variables control process (step 3). The program included 9 topics of increasing difficulty. In results, Lawson's SRT scores increased in both experimental and control groups after application of the program, but the difference was not statistically significant. After the application, there was an increase in type A and type B which implied that students' skills of control variables was improved. In addition, responses of students in the experimental group to the open-ended items showed that it was challenging for them to think scientifically and critically when controling variables, but they ended up feeling proud of their achievement after the program.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.157-157
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• 2000

In the fuzzy control for the multi-variable system, it is difficult to obtain the fuzzy rule. Therefore, the parallel structure of the independent single input-single output fuzzy controller using a pairing between the input and output variable is applied to the multi-variable system. The concept of relative gain matrix is used to obtain the input-output pairs. However, among the input/output variables which are not paired the interactive effects should be taken into account. these mutual coupling of variables affect the control performance. Therefore, for the control system with a strong coupling property, the control performance is sometimes lowered. In this paper, the effect of mutual coupling of variables is considered by tile introduction of a simple compensator. This compensator adjusts the degree of coupling between variables using a neural network. In this proposed neuro-fuzzy controller, the Neural network which is realized by back-propagation algorithm, adjusts the mutual coupling weight between variables.