• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.334-336
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• 2005

This paper proposes a simple MPPT control scheme of a Current- Control-Loop Error system Based that can be obtains a lot of advantage to compare with another digital control method, P&O and IncCond algorithm, that is applied mostly a PV system. An existent method is needed an expensive processor such as DSP that calculated to change the measure power of a using current and voltage sensor at the once. But, a proposed method is easy to solve the cost reduction and power unbalance problems that it is used by control scheme to limit error of a current control of common sensor. This proposed algorithm had verified through a simulation and an experiment on battery charger using PIC that is the microprocessor of a low price.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.693-696
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• 2003

Among many servo control systems in steel making plant, AGC system in hot rolling mill is very important to get a accurate strip thickness for good quality. AGC (Auto Gauge Control) system controls the roll gap to maintain the required thickness by using the variation of roll force and the measure of output thickness. In this paper, a simulator of AGC system which unifies both hydraulic servo control system and AGC algorithm is suggested. After proving the concurrence of algorithms between the simulator and real system, main actuator system is added. Instead of usual PI system used in present system, DOB control scheme is applied and shows the effect of disturbance attenuation well.

• 드라이브 ㆍ 컨트롤
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• 제14권4호
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• pp.61-70
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• 2017

In this study, an extended-state-observer (ESO) based non-linear servo control is introduced for an electro-hydrostatic actuator (EHA). Almost hydraulic systems not only are highly non-linear system that has mismatched uncertainties and external disturbances, but also can not measure some states. ESO that only use an output signal can be used to compensate these uncertainties and estimate unmeasurable states. To improve the position tracking performance, the barrier Lyapunov function (BLF) that can guarantee an output tolerance is introduced for the position tracking error signal of back stepping control procedures. Finally, the proposed servo control is compared with the proportional-integral (PI) control.

• Journal of Electrical Engineering and information Science
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• 제1권1호
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• pp.29-38
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• 1996

To improve the reliability of control systems, certain robustness to plant uncertainties and disturbance inputs is required in terms of well founded mathematical basis. Robust control theory was set up and developed until now from this motivation. In this field, H$_2$or H\ulcorner norm performance measures are frequently used nowadays. Moreover a mixed H$_2$/H\ulcorner control problem is introduced to combine the merits of each measure since H$_2$control usually makes more sense for performance while H\ulcorner control is better for robustness to plant perturbations. However only some partial analytic solutions are developed to this problem under certain special cases at this time. In this paper, the mixed H$_2$/H\ulcorner control problem is considered. The analytic(or semi-analytic) solutions of (sub)optimal mixed H$_2$/H\ulcorner state-feedback controller are derived for the scalar plant case and the multivariable plant case, respectively. An illustrative example is given to compare the proposed analytic solution with the existing numerical one.

• 한국치위생학회지
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• 제9권2호
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• pp.73-88
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• 2009

The purpose of the study was to provide the basic for the prevention of infection control by analyzing the level of recognition and practice of dental hygiene students. It is important for dental clinic staffs to know and practice infection control measures in favor of effective infection control. Thus, this study conducted an one-month questionnaire survey (during October 2008) for dental hygiene students who ever experienced in 16-week clinical practice, and analyzed total 206 questionnaire forms as collected from them, so that it could determine potential associations between their recognition and practice of infection control and thereby suggest an efficient solution for infection control in dental hygiene. 1. It was found that our students' recognition about infection control averaged $4.49{\pm}.58$ points on the whole, and they were best aware of instrumental disinfection and sterilization among other measures, which was followed by hand washing, extirpation control, post-sterilization management, personal protective outfit and instrumental surface maintenance respectively. 2. It was found that our students' practice of infection control averaged $3.85{\pm}.57$ points on the whole, and they practiced hand washing most actively among other measures, which was followed by extirpation control, post-sterilization management, instrumental disinfection and sterilization, personal protective outfit and instrumental surface maintenance respectively. 3. It was found that our students scored higher mean points in recognition about every measure of infection control than those in practice (t=15.676, p=0.000). Particularly, it was notable that there were significant differences between their mean points in recognition and practice of some infection control measures, such as instrumental surface maintenance (t=15.361, p=0.000), personal protective outfit (t=15.245, p=0.000) and instrumental disinfection and sterilization (t=11.169, p=0.000). But there was least significant difference between mean points in recognition and practice of hand washing (t=5.460, p=0.000). 4. For potential associations between recognition and practice of infection control, it was found that higher recognition was in significantly positive associations with higher practice in every measure of infection control (r=.478, p=.000), such as extirpation control (r=.630, p=.000), instrumental disinfection and sterilization (r=.477, p=.000) and post-sterilization management (r=.433, p=.000). 5. It was found that there were differences in our students' recognition depending upon availability of infection control guideline (t=4.587, p=.011), and there were significant differences in practice depending on necessity of infection control education on a statistical basis (t=2.229, p=.027). Overall, it is found that our dental hygiene students are very likely to practice hand washing and extirpation control, because both of these measures are relatively easy to practice or are considered legally binding.

• 대한토목학회논문집
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• 제44권5호
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• pp.683-694
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• 2024

유역에서 홍수조절 능력 증대 방안은 크게 구조적 대책과 비구조적 대책으로 구분될 수 있다. 본 연구에서는 섬진강유역 홍수조절능력 제고를 위해 비구조적 대책으로 섬진강댐 운영체제의 개선, 특히 홍수기 탄력(가변)제한수위의 도입을 제안하였다. 홍수기 제한수위의 탄력적인 운영이란 홍수기 초에는 제한수위를 낮게 설정함으로써 홍수조절용량을 증대되도록 하고 홍수기가 경과함에 따라 이를 높여 운영함으로써 댐의 홍수조절을 보다 효과적으로 하는 것이다. 구조적 대책으로는 자연기반해법(NbS)의 대표기법인 천변저류지 설치를 검토하였다. 2020년 홍수사상을 기반으로 구조적/비구조적 대책을 각각 시행했을 때와 두 대책을 동시에 시행했을 때 홍수위 저감을 분석하여 가장 효과적이고 경제적인 방안을 도출하였다. 그 결과 비구조적대책으로 홍수기 중반 섬진강댐 제한수위를 EL. 190 m로 운영하고, 구조적 대책으로 저류지를 고달교 하류 곡성군 대평리에 설치하는 것이 2020년 홍수사상시 섬진강 본류의 홍수피해예방의 최적 방안이라 검토되었다.

• 대한물리의학회지
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• 제4권1호
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• pp.43-48
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• 2009

Purpose : The purpose of this study is to determine the effects of high heeled shoes on the static balance and EMG activity of lower extremity muscles. Methods Twenty subjects were composed of control group(wearing low-heeled shoes) and experimental group(wearing high-heeled shoes). Two groups participated in bearfoot standing and measured static balance and EMG activity of lower extremity muscles. Balance Performance Monitor(BPM) was used to measure the static balance and FlexComp $Infiniti^{TM}$ was used to measure the EMG activity of lower extremity muscles. Results In static balance, sway area and path of experimental group was significantly larger than control group(p<0.05). And sway velocity of experimental group was significantly faster than control group(p<0.05). They means static balance of experimental group was significantly lower than control group(p<0.05). In EMG activity, L5 paraspinalis and biceps femoris of experimental group was significantly more increased than that of control group(p<0.05). Conclusion : The long-time experience in wearing high heeled shoes may have caused change in static balance and EMG activity of lower extremity muscles.

• 산업경영시스템학회지
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• 제40권3호
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• pp.1-6
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• 2017

Process capability is well known in quality control literatures. Process capability refers to the uniformity of the process. Obviously, the variability in the process is a measure of the uniformity of output. It is customary to take the 6-sigma spread in the distribution of the product quality characteristic as a measure of process capability. However there is no reference of process capability when maximum material condition is applied to datum and position tolerance in GD&T (Geometric Dimensioning and Tolerancing). If there is no material condition in datum and position tolerance, process capability can be calculated as usual. If there is a material condition in a feature control frame, bonus tolerance is permissible. Bonus tolerance is an additional tolerance for a geometric control. Whenever a geometric tolerance is applied to a feature of size, and it contains an maximum material condition (or least material condition) modifier in the tolerance portion of the feature control frame, a bonus tolerance is permissible. When the maximum material condition modifier is used in the tolerance portion of the feature control frame, it means that the stated tolerance applies when the feature of size is at its maximum material condition. When actual mating size of the feature of size departs from maximum material condition (towards least material condition), an increase in the stated tolerance-equal to the amount of the departure-is permitted. This increase, or extra tolerance, is called the bonus tolerance. Another type of bonus tolerance is datum shift. Datum shift is similar to bonus tolerance. Like bonus tolerance, datum shift is an additional tolerance that is available under certain conditions. Therefore we try to propose how to calculate process capability index of position tolerance when maximum material condition is applied to datum and position tolerance.

• 한국학교보건학회지
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• 제24권1호
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• pp.50-60
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• 2011

Purpose: This paper compares practical first aid training and theoretical first aid training in elementary schools. Methods: Research subjects were randomly selected and sorted into experimental and control groups. The former is one class (28 students) of the fifth grade students, and the latter is another class (30 students). In order to verify the effect of first aid training, we conducted theoretical as well as practical first-aid instruction about foreign body airway obstruction to the experimental group, but conducted only theoretical instruction with the control group. Data were analyzed by the ${\chi}^2$-test and t-test, one-way using the SPSS / win 12.0 program. The results were as follows (p=.05). Results: The first hypothesis was that the knowledge of an experimental group would be better than that of a control group. The analysis showed a significant difference (p=.000) between the two groups, supporting this hypothesis. The second hypothesis was that the experimental group would be more accurate than the control group. There was no because of (p=.000) between the two groups on this measure. The third hypothesis, that the two groups would vary over time on the measure of accuracy, was supported by the following observations: the experimental results were accumulated before, two days after and two weeks after the training (experimental group, p=.000, and control group, p=.000). This supports the third hypothesis that the technical performance accuracy levels of complete respiratory obstruction first aid vary over time. Conclusion: First aid training has to include practical education as well as theoretical education in the future, as part of a school's health education for elementary students. Health education classrooms should be prepared to teach first-aid theory and be supplied with equipment for practical exercises. Schools, communities, and private organizations need to carry out the practical education component periodically.

• 대한통합의학회지
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• 제8권4호
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• pp.171-181
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• 2020

Purpose : The purpose of this study was to investigate the effects of curl-up and proprioceptive neuromuscular facilitation (PNF) neck flexion exercises on stroke patients' trunk muscle activity, ability to control the trunk, and balance by comparing two exercise methods. Methods : The study involved patients who had been diagnosed with stroke based on the results of computerized tomography or magnetic resonance imaging at O Hospital in Daegu, South Korea, between January and July 2020. In total, 30 subjects were selected and by flipping a coin, randomly assigned to an experimental group (n=15) that performed PNF neck flexion exercises and a control group (n=15) that performed curl-up exercises. Both groups received traditional rehabilitation therapy for 30 minutes a day five times a week for a six-week period. In addition, the experimental group performed PNF neck flexion exercises and the control group curl-up exercises for 15 minutes a day five times a week over the same period. The subjects' muscle activity in the rectus abdominis (RA), external oblique (EO), and internal oblique (IO) were measured before and after the experiment. The subjects' trunk impairment scale (TIS) and Berg balance scale (BBS) scores were also assessed. Paired t test was performed to measure the amount of statistical change before and after intervention in both groups. An independent sample T test was performed to measure the amount of statistical change between the two groups. Results : Both groups experienced statistically significant increases in their RA, IO and EO muscle activity, total TIS scores, and total BBS scores after the intervention. No statistically significant differences in the changes before and after the intervention were found for any of the resulting values between the two groups. Conclusion : A comprehensive review of the study's results suggested that neck flexion exercises using the PNF irradiation concept and curl-up exercise are effective in increasing stroke patients' abdominal muscle activity and improving trunk control ability and balance in chronic stroke patients.