• Journal of Institute of Control, Robotics and Systems
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• v.21 no.2
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• pp.137-144
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• 2015

In hybrid or electric vehicles, the hydraulic brake system must be controlled cooperatively with the traction motor for regenerative braking. Recently, a motor driven brake system with a PMSM (Permanent Magnet Synchronous Motor) has replaced conventional vacuum boosters to increase regenerative power. Unlike industry motor controls, additional source codes such as functional safety are essential in automotive applications to meet ISO26262 standards. Therefore, the control logic execution time increases, which also causes an extension of the motor current control period. The increased current control period makes precise motor current control challenging inhigh speed ranges where the motor is driven by high frequency. In this paper, a PWM update strategy and a time delay compensation method are suggested to improve current control and system performance. The proposed methods are experimentally verified.

• Child Health Nursing Research
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• v.22 no.3
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• pp.172-181
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• 2016

Purpose: This study was conducted to examine the effect of education on infection control for multidrug resistant organism (MDRO). Methods: One group pre-post time series design was used. Infection control education for MDRO infection was provided to nurses working in the Neonatal Intensive Care Unit (NICU). Knowledge and recognition were evaluated before and after education. Hand hygiene compliance, MDRO isolation rate and central line-associated bloodstream infection (CLABSI) rate were used as outcome variables. Data from 45 nurses was used for analysis. Results: General knowledge about MDRO increased (p=.011). Responses to questions about image of MDRO and MDRO management tended to change in a positive direction (p=.046). Hand hygiene compliance was 100% at pre-test, 79.5% during education period and 98.4% at post-education period. MDRO isolation rate was 6.83 per 1,000 patient days at pre-test, 10.24 during education period and 6.68 at post-education period. CLABSI rate was 3.76 per 1,000 central line days at pre-test, 6.84 during education period and 4.71 at post-education period. Conclusion: Findings indicate that the education program is effective in improving knowledge about MDRO in NICU nurses. However, more reliable indicators should be used to determine long-term effects.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.4
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• pp.346-352
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• 2006

In a networked control system (NCS), time delays which are larger than one sampling period can change the control period. As a result, it may cause system instability. This paper presents a control method for an NCS using the controller area network (CAN), where time delays arise in the control loop. Specifically, a simple yet efficient method is proposed to improve control performance in the presence of time delays. The proposed method, which can be regarded as a gain scheduling method, selects a suitable LQ control gain among several gains to deal with the problems due to the change of control period. It is found that the gain can be scheduled in terms of the relation between the gain and the sampling period, which is represented by first-order algebraic equations. The proposed method is evaluated with an inverted cart pendulum system where the actuator and sensors are connected through the CAN. Experiment results are presented to show the efficiency of the proposed method.

• Nuclear Engineering and Technology
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• v.23 no.1
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• pp.30-40
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• 1991

For automatic power control of KMRR, a new method, Reactivity Constraint Method, is applied for time optimal control. This method limits the net reactivity to the amount that can be offset by instantaneous control rod action. The reactivity to be constrained for the constant reactor period should be obtained by the dynamic period equation. A new formulation of the dynamic period equation for 2-point kinetics model is presented. A methematical controller model was applied to the plant simulator, KMRSIM to test this control law. The performance test showed that reactivity constraint approach is also a reliable means for reactor power change control.

• Nuclear Engineering and Technology
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• v.27 no.1
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• pp.8-17
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• 1995

A great effort has been made to improve the nuclear plant control system by use of digital technologies, and a long term schedule for the control system upgrade has been prepared with an aim to implementation in the next generation nuclear plane. In case of digital control system, it is important to decide the sampling period for analysis and design of the system, because the performance and the stability of a digital control system depend on the value of the sampling period of the digital control system. There is, however, currently no systematic method used universally for determining the sampling period of the digital control system. Generally, a traditional way to select the sampling frequency is to use 20 to 30 times the bandwidth of the analog control system which has the same system configuration and parameters as the digital one. In this paper, a new method to select the sampling period is suggested which takes into account of the performance as well as the stability of the digital control system. By use of the frying's model of steam generator, the optimal sampling period of an assumptive digital control system for steam generator level control is estimated and is actually verified in the digital control simulation system for KORI-2 nuclear power plant steam generator level control. Consequently, we conclude the optimal sampling period of the digital control system for KORI-2 nuclear power plant steam generator level control is 1 second for all power ranges.

• Child Health Nursing Research
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• v.5 no.3
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• pp.250-261
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• 1999

This study has been conducted on the nonequivalent control group Pretest-posttest design in quasi experimental basis and newly born premature infants from intensive care unit of G Medical University Hospital in Inchon Metropolitan were selected in two groups of 21 infants each. The first group for experimental and the other for control. Data has been collected form October 30, 1997 to August 29, 1998. For the experimental group tactile and kinesthetic stimulation was applied 2 times a day for 10 days(10:00～ll:00 hours in the morning and 17:00～18:00 in the afternoon). As, a weight weighing instrument, electronic indicator scale(Cas Co. korea) was used. Collected data were analyzed with the SAS program using x²-test, student t-test, repeated measures ANOVA, Pearson correlated coefficient and Stepwise multiple regression. The result were as follow. 1. As for the daily weight gain, the experimental group showed first change in weight and this group also showed higher weight in the average weight than the control group. Statistically, however. there was no significant factor between the two groups. 2. In the correlation between general characteristics and weight gain, gestation Period. apgar score, admission Period before study, N.P.O. period after birth, recovery Period to birth weight showed statistical significance negative correlation with weight gam in the experimental group than control group. 3. In the factor with affected the weight gain by general characteristics showed recovery period to birth weight and head circumference in the experimental group, control group showed recovery period to birth weight, N. P. O. period after birth. admission period before study, feeding amount, weight of study. In conclusion. the sensory stimulation in this study showed a Positive aspect through there was no statistical significance in the weight gam. Tn the correlation of general characteristics and weight gam showed statistical significance negative correlation The main factor which affected the weight gain by general characteristics showed recover period to birth weight.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.100-103
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• 1999

In this paper, a method for the efficient implementation of the PICNET network configurator for a distributed control system(DCS) is proposed. The network configurator is composed of the time parameter estimator and the period scheduler, the file generator. The main role of network configurator estimates time parameter, the pre-run time scheduling of the user input and make the period transmission table for operating the PICNET based distributed control system.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.3
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• pp.206-211
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• 2004

In phase controlled rectifier, it's been known that a fast response is achieved by predictive current control without any overshoot. The frequent sampling period is essential to improve the firing accuracy in conventional predict current control. However, improving the firing accuracy if difficult to reduce the period of sampling efficiently because current sampling and predictive current control is carried out in every period and the ON-OFF current control is performed by comparing two different one. To improve the firing accuracy at the predictive current control, the calculated firing angle is loaded into the high-accuracy hardware timer. So the calculation of exact crossing point between the predictive and actual current is the most important. In this paper, the flow chart for proposed firing angle calculation algorithm is obtained for the fastest current control performance in transient state. The performance of proposed algorithm is verified through simulations and experiments.

• The Korean Nurse
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• v.33 no.1
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• pp.37-51
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• 1994

The cutaneous stimulation is an independent nursing intervention used in various painful conditions, and is explained by gate control theory. This study was aimed at identifying the effect of cutaneous stimulation on reduction of arteriovenous fistula puncture pain of hemodialysis patients. One group repeated measurement post test research was designed. Forty-five hemodialysis patients who received arteriovenous fistula puncture regulary in hemodialysis units of an attacted D hospital to K university have been studied from August 16 to 21, 1993. First the arteriovenous fistula puncture pain of control period was measured, and then the arteriovenous fistula puncture pain of experimental period(with cutaneous stimulation) was measured. The instrument used for this study were visual analogue pain scale as subjective pain measurement, objective pain behavior checklist and Spielberger's Trait Anxiety Inventory as intervening variables. Analysis of data was done by use of paired t-test, t-test, ANOVA and Perarson correlation coefficient. The results of this study were summarized as follows; 1) The first hypothesis that the subjective pain score of arteriovenous fistula puncture pain in experimental period(with cutaneous stimulation) will be lower than in control period was partly supported. The subjective pain score of arterial line was rejected(paired t=-0.28, p=0.77) and the subjective pain score of venous line was supported(paired t=2.61, p=0.01). 2) The second hypothesis that the objective pain behavior score of arteriovenous fistula pain in experimental period(with cutaneous stimulation) will be lower than in control period was rejected(arterial line paired t=-0.45, p=0.65; venous line paired t=-0.36, p=0.72). 3) The third hypothesis that the cardiopulmonary signs of arteriovenous fistula puncture pain in experimental period(with cutaneous stimulation) will be lower than in control period was rejected(pulse paired t=-0.8, p=0.42; systolic BP paired t=0.98, p=0.33; diastolic BP paired t=0.43, p=0.66). Further experimental studies with simple intravenous injection patients will be recommended in order to identify the effect of cutaneous stimulation.

• The korean journal of orthodontics
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• v.22 no.3 s.38
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• pp.617-626
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• 1992

This study was conducted for the assessment of the usefulness of masseteric silent period on electromyogram as a diagnostic method for temporomandibular disorder. Of students and dentists in Dental College of Yonsei University and patients, 36 experimental subjects with symptoms such as clicking bound, pain in the temporomandibular joint area and limitation of jaw movement, and 33 control subjects without such symptoms were selected for this study. On each subject electromyographic masseter muscle silent period followed by mention tap was recorded with surface electrodes and analysed with computerized system. The following results were obtained: 1. The mean silent period was $36.97{\pm}9.23$ msec in experimental group, and $25.62{\pm}5.24$ msec in control group respectively. 2. There were no statistically significant differences in silent period between male and female in either experimental and control group. 3. Silent periods in experimental group were more prolonged than those of control group. (P < 0.01) Taken all together, electromyographic masseter muscle silent period may be useful for diagnosis and evaluation of temporomandibular disorder.