• Solar Energy
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• v.5 no.2
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• pp.77-83
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• 1985

An analysis is performed to investigate the influence of the buoyancy force and the thickness variation of melting layer in the containment that is filled with phase-change Material surrounding a cylindrical heating tube during melting process. The phase-change material is assumed to be initially solid at its phase-change temperature and the remaining solid at any given time is still at the phase-change temperature and neglecting the effect of heat transfer occuring within the solid. At the start of melting process, the thickness of melting layer is assumed to be a stefan-problem and after the starting process, the change of temperature and velocity is calculated using a two dimensional finite difference method. The governing equations for velocity and temperature are solved by a finite difference method which used SIMPLE (Semi Implicit Method Pressure linked Equations) algorithm. Results are presented for a wide range of Granshof number and in accordance with the time increment and it is founded that two dimensional fluid flow occurred by natural convection decreases the velocity of melting process at the bottom of container. The larger the radius of heating tube, the higher heat transfer is occurred in the melting layer.

• Korean Journal of Health Education and Promotion
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• v.23 no.1
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• pp.63-75
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• 2006

Objective: This study was performed to identify the related factors of change affecting the stage of change, on the assumption that there are various stages of change in the exercise behavior of workers. Method: The subjects of the study consisted of 138 workers of 10 workplaces located in Daejeon City, and data collected by using questionnaires were analyzed with SPSS/WIN 11.5 program. Results: The subjects were distributed in the stage of exercise behavior change as follows: precontemplation stage(10.9%), contemplation stage(22.5%), preparation stage(41.3%), action stage(8.7%), and maintenance stage(16.7%). Of the process of change depending on the stage of exercise behavior change, the consciousness raising(F=11.50, p=.00), dramatic relief(F=2.82, p=.02) showed significant difference in the cognitive process, and the counter conditioning(F=4.56, p=.00), reinforcement management(F=4.64, p=.00), self-liberation(F=9.46, p=.00), and stimulus control(F=13.28, p=.00) showed significant difference in the behavioral process. For decision-making depending on the stage of exercise behavior change, both the pros of decision-making(F=9.23, p=.00) and the cons of decision-making(F=2.45, p=.04) showed significant difference. Self-efficacy depending on the stage of exercise behavior change showed significant difference as F=11.50, p=.00. The related factors of change affecting the stage of exercise behavior change were the pros of decision-making, the cons of decision-making, and self-efficacy including 34.1% R-square. Conclusion: In order to change the exercise behavior of workers positively, they need to be stimulated to use the cognitive and behavioral process in the process of change properly, and to be induced to make a decision positively. And also exercise programs suitable to various characteristics of each worker as well as those of workplaces to enhance self-efficacy need to be applied after being devised. Through the further longitudinal research, it is necessary to analyze the various aspects, such as groups to select, to maintain, to stop or give up the exercise, and to avoid the change, and to study how the related factors of change affect diversity like the above.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.76-80
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• 1991

This paper presents a merit of feedforward Dyamic Matrix Control(DMC) for electrolyzer process. The electrolyzer consists of anode part and cathode part that are separated by ion membrane. As the electolyzer process consumes a large amount of electricity, electric power change is inevitable in order to take advantage of the cheaper electricity during night. But the electric power change makes the electrolyzer control difficult because the electric power change affect the dynamics of the process. Feedforward DMC treats the electric power change as a load disturbance and gives the weighting value to the disturbance prediction part in the DMC algorithm. Feedforward DC shows better regulation performance than PID control and feedforward-feedback control for electrolyzer process.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2505-2510
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• 2009

Semiconductor processes need measurement to confirm where there are problems in quality after progresses manufacturing process. This paper suggests equipment and automatic measure sampling method that control monitoring ratio according to change point occurrence availability of process that is not measure method by the existent simple ratio rate. This paper defines measure section as ailment section, metastable section and stability section by change point standard and create statistical model of each section and developed suitable measure rate model by section. As a result, we have accomplished maximum throughput and minimum sampling number that needs to maintain constant level of quality. Proposed method minimizes load of measure process by brings production quality sophistication and decrease of process badness and lowers measure rate in stable section making perception about problem occurrence quick heightening measure rate at change point occurrence.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.10 no.2
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• pp.138-144
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• 2003

Purpose: The purpose of this study was to identify the change processes for exercise behaviors in each stage. Method: Participants for this study were randomly selected from adults between the ages of 20-44. Data were collected using questionnaires over a 2 week period at the end of May, 2003. The instrument, Stages of exercise behavior change developed by Marcus et al. (1992b), and the instrument, Changing phases of exercise behaviors developed by Nigg et al. (1999) and translated by Kwon (2002) were used to investigate the behaviors. Result: 1. Related to stage of exercise behavior change of participants, it was found that 55.2% of participants exercised regularly. 2. Among the change processes according to stage of change showed that dramatic relief was the most frequently used process for all stages. Environmental reevaluation and social liberation were used most in the contemplation stage, while environmental reevaluation and stimulus control were used most in the preparation stage. In addition, scores for stimulus control and environmental reevaluation were high in the action stage. In the maintenance stage, social liberation and counter-conditioning were used most frequently. 3. The process of exercise behavior change which differentiates the stages of exercise behavior change were shown to be counter-conditioning, which was an influential factor that differentiates the contemplation stage and maintenance stage. Conclusion: The results suggest that change process management should be the focus to enhance the stage of change for exercise in this group.

• Journal of Korean Public Health Nursing
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• v.26 no.1
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• pp.147-157
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• 2012

Purpose: The purpose of this study was to identify the related factors of change affecting the stages of change for exercise, on the assumption that there are various stages of change in the exercise behavior of women in nursing college. Methods: The subjects were 496 female college students in D city. The research instruments were stages of change for exercise behavior, the process of change, decisional balance, and self-efficacy. The dates were analyzed by descriptive statistics, ANOVA, and stepwise multiple regression using the SPSS 18.0 program. Results: The distribution of the subjects across the stages was: pre-contemplation, 17.7%; contemplation, 58.7%; preparation, 19.0%; action, 2.8%; maintenance, 1.8%. Analysis of variance showed that cognitive process (F=17.26, p<0.01), behavioral process (F=27.05, p<0.01), the pros of decisional-balance (F=7.07, p<0.01), the cons of decision-balance (F=5.82, p<0.01), and self efficacy (F=17.79, p<0.01) were significantly associated with the change of exercise behavior stages. The related factors of change affecting the change of exercise behavior stage were the cons of decision-making, counter conditioning, self re-evaluation, and body mass index, including 28.4% R-square. Conclusion: The transtheoretical model would be applicable to explain the exercise behavior of some women in nursing college. So, this study will be useful information for developing effective exercise behavior programs considering female students' stages of change.

• Korean Journal of Health Education and Promotion
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• v.27 no.2
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• pp.79-93
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• 2010

Objectives: This study aims to identify the factors associated with the stages of change in colorectal cancer screening, and develop a model explaining these stages of change by using structural equation modeling analysis. Methods: On the basis of literature review and expert advice, we constructed our hypothetical model that consisted of five theoretical constructs(process of change, pros, cons, self-efficacy, stage of change). In 2009, data was collected from 486 participants aged between 50 and 69. The data were analyzed by SPSS 15.0 and AMOS 6.0. Results: In the case of stage of adoption, the contemplation stage was the most common (37.4%), followed by the action stage (26.5%). In the final model of the stage of change for colorectal cancer screening, there was a direct influence of the process of change ($\gamma$=.562, p<.001), and cons ($\gamma$=.132, p<.01) on the stage of change with the terms of GFI .931, AGFI .904, RMR .038, NFI .930, and NNFI .936. Conclusion: It is necessary to produce and disseminate evidence-based cancer screening information, which can mitigate the negative attitude among the public toward cancer screening. Also, it is essential to provide a safer and more comfortable environment at cancer screening center.

• 한국경영정보학회:학술대회논문집
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• 2008.06a
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• pp.338-343
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• 2008

Government intervention, industry cooperation, new vendors, and foreign competition are all factors that exert a powerful influence on the information technology, marketplace, and on the individual IS organization. When these influences need to change an organization, it is likely the culture or identity of the organization will be targeted for change. Because an organization is also composed of cognitive frameworks, there is an implication that the existing cognitive structures are in jeopardy. Thus, the cognitive component is important in how all members of organizations react and respond to change. This paper defines cognitive process and its related research history, introduces organizational change matters, tries to solve conflicts in organizational changes, and applies this topic to the information systems field.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2004.04a
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• pp.97-106
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• 2004

The paper making process itself is a typical nonlinear process with complicated dynamics. In the application of advanced control-methods especially for the grade change operations the nonlinear process is linearized to give suitable linear models to be used in the control strategies. However, the use of the linear model is limited within short range containing steady-state operating conditions for grade change operation. In this paper a bilinear model for the nonlinear grade change processes is presented. We can see that the dynamic behavior for grade change operations can be effective analyzed by using multivariable bilinear model.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2003.11a
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• pp.291-305
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• 2003

In this work we developed the closed-loop model of a paper machine during grade change with the intention to provide a reliable dynamic model to be used in the model-based grade change control scheme. During the grade change, chemical and physical characteristics of paper process change with time. It is very difficult to represent these characteristics on-line by using physical process models. In this work, the wet circulation part and the drying section were considered as a single process and closed-loop identification technique was used to develop the grade change model. Comparison of the results of numerical simulations with plant operation data demonstrates the effectiveness of the model identified.