• 제목/요약/키워드: Control variables

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Multivariate Control Charts for Autocorrelated Process

  • Cho, Gyo-Young;Park, Mi-Ra
    • Journal of the Korean Data and Information Science Society
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    • 제14권2호
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    • pp.289-301
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    • 2003
  • In this paper, we propose Shewhart control chart and EWMA control chart using the autocorrelated data which are common in chemical and process industries and lead to increase the number of false alarms when conventional control charts are applied. The effect of autocorrelated data is modeled as a autoregressive process, and canonical analysis is used to reduce the dimensionality of the data set and find the canonical variables that explain as much of the data variation as possible. Charting statistics are constructed based on the residual vectors from the canonical variables which are uncorrelated over time, and the control charts for these statistics can attenuate the autocorrelation in the process data. The charting procedures are illustrated with a numerical example and simulation is conducted to investigate the performances of the proposed control charts.

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자기상관자료를 갖는 공정을 위한 다변량 관리도 (Multivariate Control Chart for Autocorrelated Process)

  • 남국현;장영순;배도선
    • 대한산업공학회지
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    • 제27권3호
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    • pp.289-296
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    • 2001
  • This paper proposes multivariate control chart for autocorrelated data which are common in chemical and process industries and lead to increase in the number of false alarms when conventional control charts are applied. The effect of autocorrelated data is modeled as a vector autoregressive process, and canonical analysis is used to reduce the dimensionality of the data set and find the canonical variables that explain as much of the data variation as possible. Charting statistics are constructed based on the residual vectors from the canonical variables which are uncorrelated over time, and therefore the control charts for these statistics can attenuate the autocorrelation in the process data. The charting procedures are illustrated with a numerical example and Monte Carlo simulation is conducted to investigate the performances of the proposed control charts.

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강우시 철도성토사면의 열차운전규제기준에 관한 연구 (A Study on the rail-transport operation control for railway embankment under rainfall)

  • 김현기;박영곤;신민호;김수삼
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2001년도 추계학술대회 논문집
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    • pp.514-519
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    • 2001
  • There are a close relationship between natural disasters and train safety. So it is very important to guaranty train safety using reasonable rail-transport operation control against disasters. Therefore, based on the past record of rainfall at failure, rail-transport operation control for railway embankment under rainfall was set up. After slope check list at home and abroad had been analyzed, new slope check list was suggested and site investigations were carried out using this check list. In order to evaluate the stability of railway slopes under rainfall, explanatory variables and subordinate variables were selected for multi-variate analysis and critical rainfall was defined by statistical process. Rail-transport operation control including regional and geological properties was suggested by analyzing the critical rainfall and rail-transport operation control in other country, and this will be a good tool to control train speed under rainfall and to secure train safety.

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전기유압식 모터용 위치제어 시스템의 설계 (Design of a Position Control System for Electro-hydraulic Motors)

  • 박진길;진강규;노영오;한봉주;정주윤;박재식
    • Journal of Advanced Marine Engineering and Technology
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    • 제16권3호
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    • pp.30-41
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    • 1992
  • For the state feedback controller which measures only partial state variables, a state observer can be used to give the estimates of unmeasurable states. In this paper, the delayed state feedback method instead of the state observer for desingning a tracking controller of electro-hydraulic control system is presented. The controller design is based on augmenting the original system by one additional integral and proportional element which compensates for the effect of the integral control and on feeding back the measurable state variables and their delayed values. The performance of the proposed position control system is compared with both that of the full state feedback control system and that of the digital PID control system tuned by the Ziegler-Nichols method and by the parameter readjustment through the computer simulation. And then robustness against unmeasurable constant disturbace and parameter variations during operations is also checked.

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효모 배양을 위한 발효공정의 최적화 및 적응제어 (Optimization and Adaptive Control for Fed-Batch Culture of Yeast)

  • 백승윤;유영제이광순
    • KSBB Journal
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    • 제6권1호
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    • pp.15-25
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    • 1991
  • The optimal glucose concentration for the high-density culture of recombinant yeasts was obtained using dynamic simulation. An adaptive and predictive algoritilm complimented by the rule base was proposed for the control of the fed-batch fermentation process. The measurement of process variables has relatively long sampling period and relatively long time delay characteristics. As one of the solution on these problems, prediction techniques and rule bases were added to a classical recursive identification and control algorithm. Rule bases were used in the determination of control input considering the difference between the predicted value and the measured value. A mathelnatical model was used in the estimation and interpretation of the changes of state variables and parameters. Better performances were obtained by employing the control algorithm proposed in the present study compared to the conventional adaptive control method.

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PID 제어기를 이용한 좌심실보조장치의 제어 (PID control of left ventricular assist device)

  • 정성택;김훈모;김상현
    • 제어로봇시스템학회논문지
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    • 제4권3호
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    • pp.315-320
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    • 1998
  • In this paper, we present the PID control method for the controlling flow rate of highly complicated nonlinear Left Ventricular Assist Device(LVAD) with pneumatically driven mock circulatory system. Beat Rate (BR), Systole-Diastole Rate (SDR) and flow rate are used as the main variables of the LVAD system. System modeling is completed using the neural network with input variables (BR, SDR, their derivatives, actual flow) and an output valiable(actual flow). Then, as the basis of this model, we perform the simulation of PID control to predict the performance and tendency of the system and control the flow rate of LVAD system using the PID controller. The ability and effectiveness of identifying and controlling a LVAD system using the proposed algorithm will be demonstrated through computer simulation and experiments.

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부모요인과 아동의 기질 및 내재적 통제소재가 자기조절능력에 미치는 영향 (Effects of Parental Variables, Temperament and Internal Locus of Control on Self-Regulation of Children)

  • 이경님
    • 가정과삶의질연구
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    • 제28권6호
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    • pp.47-57
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    • 2010
  • This study examines the effects of parental variable(parental support and supervision), temperament(activity level, attention span/persistence, and emotionality) and the internal locus of control on self-regulation of children. Data were collected from 455 5th and 6th graders and analyzed with Pearson's correlations and pathway analysis. The results were as follows : Children's temperament, internal locus of control and parental variable directly affected children's self-regulation. Parental variables mediated between children's temperament and internal locus of control and self-regulation. Internal locus of control mediated between children's temperament and self-regulation: in addition, the most important variable predicting children's self-regulation was children's attention span/persistence temperament.

Development of Intelligently Unmanned Combine Using Fuzzy Logic Control -(Graphic Simulation)-

  • N.H.Ki;Cho, S.I.
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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    • pp.1264-1272
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    • 1993
  • The software for unmanned control of three row typed rice combine has been developed using fuzzy logic. Three fuzzy variables were used : operating status of combine, steering, and speed. Eleven fuzzy rules were constructed and the eleven linguistic variables were used for the fuzzy rules. Six sensors were use of to get input values and sensor input values were quantified into 11 levels. The fuzzy output was infered with fuzzy inferrence which uses the correlation product encoding , and it must have been defuzzified by the method of center of gravity to use it for the control. The result of performance test using graphic simulation showed that the intelligently unmanned control of a rice combine was possible using fuzzy logic control.

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뇌졸중 환자를 위한 팀접근 재활프로그램의 효과 (The Effect of a Multidisciplinary Team Approach on the Rehabilitation of Stroke Survivors)

  • 조복희
    • 재활간호학회지
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    • 제6권2호
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    • pp.137-151
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    • 2003
  • The purpose of this study was to develop a multidisciplinary team approach program for stroke survivors, and to identify its effects on their rehabilitation. The team was composed of 7 members: a rehabilitation nurse, a physician, a physical therapist, an occupational therapist, a therapeutic recreational therapist, a nutritionist, and a researcher. A quasi-experimental study was performed with 36 subjects: 18 in the experimental group and 18 in the control group, using a noneqivalent control group pretest-posttest design. The experimental group participated 4 times in rehabilitation programsfocused on information and emotional support provided by the rehabilation team-and received telephone counseling from the researcher. The control group did not receive any treatment. The selection criteria for the subjects in this study were: (a) patients who were diagnosed as having had an ischemic stroke within the last year, (b) patients free of any communication disorder, (c) and those having a primary caregiver who could assist in filling out the form assessing the level of ADL. The data were collected from patients who had been discharged from a tertiary hospital, between October 1st, 1999 and September 30th, 2000. The data were analysed by $X^2$ test, Fisher's exact test, ANCOVA, Wilcoxon's rank sum test, and Wilcoxon's signed rank test using an SAS program. The results were as follows: 1. In terms of physical variables (blood pressure, grasp power, and ADL) 1) There was a significant difference in blood pressure between the two groups (systolic pressure P= .012, diastolic pressure P= .050). 2) There was also a significant difference in grasp power between the two groups (affected side : P= .012, unaffected side : P= .010). 3) There was no significant change in the level of ADL between the two groups. 2. In terms of psychosocial variables (depression, self-efficacy, self-esteem, and social activities) 1) There were no significant differences between the two groups. However, all four psychosocial variables showed a tendency to improve in the experimental group, while only two variables (depression and self-efficacy) showed a simalar tendency in the control group. 2) The level of social activities in the control group decreased significantly after a month (P= .050). 3. The level of life satisfaction improved in both groups, but no significant difference was found. Stroke has high recurrence rate and requires considerable follow-up care. The program used in this study was developed and designed for stimulting the rehabilitation process of stroke survivors. Through the program period of one month (meetings were held weekly), a positive effect was detected in physical variables, although the psychosocial variables did not improve significantly. In retrospect, a one month period may not be an adequate length of time to improve the psychosocial variables, as the stroke survivors were complicated cases, and most of them were elderly. Further research is therefore recommended by increasing the length of program, so that its effect can be more noticeable.

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아동의 자기통제와 관련변인간의 인과관계-아동의 사려성, 자아개념 및 어머니의 양육행동을 중심으로- (The Causal Relations of Childrens's Self-Control and Related Variables: Focusing on the Children's Refelction, Self-Concept and Mother's Parenting)

  • 이경님
    • 대한가정학회지
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    • 제39권2호
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    • pp.97-110
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    • 2001
  • The purpose of this study was to analyze a causal relations of children's self-control, self-concept, reflection, age, sex and mother's parenting. The subjects were 86 children of 5-and 6-year=olds, and their mothers and leachers. The instruments were TSCRS, MFFT, Self-concept inventory and Parenting scale. The major findings of this study were as follows; (1) Children's reflection, social self-concept and mother's control parenting predicted children's self-control. 20% of the valiance of children's self-control was explained by these variables. (2) Children's reflection was the first contribution factor and had a direct positive effect on children's self-control. Children's social self-concept had a direct positive effect on children's self-control. Mother's control parenting had a direct negative effect on children's self-control. (3) Mother's affect parenting had an indirect positive effect through children's reflection and social self-concept on children's self-control. Children's sex had indirect effect through mother's control and affect parenting on children's self control. Children's age had indirect effect through children's reflection and mother's control parenting on children's self-control.

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