• Journal of the Korean Society of Systems Engineering
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• v.17 no.1
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• pp.11-20
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• 2021

Decontamination of systems, structures and components (SSC) during the decommissioning of a Nuclear Power Plant (NPP) can be for a variety of reasons. The main reasons for decontamination are: to reduce the contamination of SSC to a reasonably low level, to reduce the potential for the spread of contaminants into the environment and to reduce the cost of disposal due to the reduced level of contamination in a particular SSC. The decontamination technique can be aggressive or non-aggressive depending on the intent after the decontamination process. Aggressive decontamination technique is used when the intent is not to reuse the SSC while a non-aggressive decontamination technique is used with the intent of SSC reuse. For different SSCs there are different decontamination techniques that can be used, each having its own advantages and drawbacks. Metal components such as pipes in the nuclear power plant account for a large amount of nuclear wastes generated. Some of these wastes can be reused if the contaminant level is reduced to an acceptable level. Laser ablation is a non-aggressive decontamination technique that can be used to reduce the contamination in pipes to an acceptable level with no secondary waste generated during the process. The operation and control of a laser ablation device must be precise to achieve a high decontamination factor. This precision can be achieved by a well-designed motion control system. For this purpose, a motion control system was developed consisting of two parts: the first part being the precise control of the laser ablation device inside the pipe and the second part is the control of the laser ablation device outside the pipe. This paper describes the Systems Engineering approach for the development process of a motion control system for the Laser decontamination system.

• Journal of Biosystems Engineering
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• v.29 no.5 s.106
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• pp.425-432
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• 2004

In harvesting rice and barley using combine, the inclination of the body caused by the irregular surface condition of the field and the soil sinking from the unbalanced weight during the grain collection used to make harvesting operation difficult and even impossible. To overcome such a problem hydraulic system far automatic and manual leveling control of a combine has been developed. The system was composed of the combine body and the hydraulic level control system mounted on it. The maximum height of ground clearance was set up to be 290mm. And the limit angle of the leveling control was set up to be $\pm7^{\circ}$. The proposed controller and hydraulic system was implemented to the prototype combine. The prototype combine was designed and built as a separable structure with the body and the track of it. This paper shows results of a specification and design testing with the hydraulic level control system far body of combine.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.4
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• pp.306-311
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• 1996

This paper discusses the maintenance of the water level of steam generators at its programmed value. The process, the water level of a steam generator, has the nonminimum phase property. So, it causes a reverse dynamics called a swell and shrink phenomenon. This phenomenon is severe in a low power condition below 15 %, in turn makes the start-up of the power plant too difficult. The control algorithm used here incorporates a pole-assignment scheme into the minimum variance strategy and we use a parallel adaptation algorithm for the parameter estimation, which is robust to noises. As a result, the total control system can keep the water level constant during full power by locating closed-loop poles appropriately, although the process has the characteristics of high complexity and nonlinearity. Also, the extra perturbation signals are added to the input signal such that the control system guarantee persistently exciting. In order to confirm the control performance of a proposed pole-assignment self-tuning controller we perform a computer simulation in full power range.

• Journal of Sasang Constitutional Medicine
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• v.19 no.2
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• pp.155-169
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• 2007

1. Objectives This study aimed to investigate the anti-oxidative effect of Nocyongdaebo-tang (NYD) decoction in oxidized rats induced by AAPH. 2. Methods AAPH (2.2-azobis-2 aminodinopropane-hydrochloride) was injected intraperitoneally to induce oxidization and NYD was orally administered to the rats. To observe the anti-oxidative effect of NYD, we performed blood chemistry analysis, histological analysis, and evaluated the levels of SOD, catalase, glutathione, NO and MDA in liver. 3. Results & Conclusions 1) Serum Albumin level was increased significantly in the NYD group as compared with the control group and the saline group. 2) Serum LDL-cholesterol level was reduced significantly in the NYD group as compared with the control group. 3) GPT level in liver was reduced significantly in the NYD group as compared with the control group. 4) SOD, catalase activity and glutathione levels were increased significantly in the NYD group as compared with the control group and the saline group. 5) The levels of NO and MDA were reduced significantly in the NYD group as compared with the control group. 6) The degenerative change of liver tissue of NYD group was decreased in comparison with the control group. In conclusion, NYD decoction is considered to have an anti-oxidative effect in rats.

• Journal of Korean Public Health Nursing
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• v.19 no.1
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• pp.95-107
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• 2005

With the aim of diagnostic research on health education. the health promoting behaviors related to elementary school students' weight control. life satisfaction. health state. self-efficacy. parent's interest and knowledge about weight control and school health education of weight control were investigated on the basis of the PRECEDE model. The data for this study were collected from a sample at an elementary school in Chongju for 5 days in July. 2004. In analyzing the data. t-test. one-way ANOVA. chi-square test and multiple regression analysis were done by using SPSS 10.1 The results were as follows : 1. The elementary school students' level of life satisfaction was above half of the full point. The score difference of life satisfaction was statistically significant by grade and academic achievement(F=4.646. p=.010. F=16.042. p=.000). 2. The perceived level of health state was moderate for all students. Normal weight students' level was significantly higher than obese students' (t=3.667. p=.000). 3. The perceived level of health promoting behaviors related to weight control was above the moderate. The perceived level of health promoting behaviors related to weight control in the obese students was significantly higher than that in normal weight students(t=-2.225. p=.027). The students used computer for 1.48 hours and watched TV for 2.52 hours a day. 4. The score of health promoting behavior self-efficacy in this subject was 70.61. 5. The parents' level of interest in the obese students' weight control was significantly higher than that in the normal weight students(t=-4.86. p=.000). 6. Sixty-six percent of the students learned about weight control education in school. 7. The health promoting behavior self-efficacy among the educational diagnostic variables was the most influential variable in students' health promoting behaviors related to weight control. This research diagnosed the needs of weight control education in elementary school by assessing various factors related to weight control behaviors. The research findings suggest that we can enhance the prevention of childhood obesity by strengthening the related factors such as parents' knowledge and interest, health promoting behaviors and self-efficacy related to weight control in school health education.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.4
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• pp.291-297
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• 2012

Recently, Switching devices become cheaper, depending on the multi-level inverters are considered as the power-conversion systems for high-power and power-quality demanding applications. The multi-level inverters can reduce the THD(Total Harmonic Distortion) as the output which is similar sinusoidal waveform by synthesizing several capacitor DC voltages. However it has some disadvantages such as increased number of components, complex PWM control method. Therefore, this paper is proposed the new multi-level inverter topology using an new H-bridge output stage with a bidirectional auxiliary switch. The proposed topology is the 4-level 3-phase PWM inverter with less switching part than conventional multi-level inverters and reactive power control possible. In order to understand the new multi-level inverter, topology analysis and switching patterns and modes according to the current loop are described in this paper. The proposed multi-level inverter topology is validated through PSIM simulation and the experimental results are provided from a prototype.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.10 no.2
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• pp.1-6
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• 2012

Purpose : This study is to investigate the modulatory effects to the ultraviolet induced erythema of pain processing system. Methods : Thirty six healthy volunteers were divided into none treatment group (n=6), indomethacine group (n=6), subsensory level electrical stimulation group (n=6), sensory level electrical stimulation group (n=6), motor level electrical stimulation group (n=6), noxious level electrical stimulation group (n=6). Subjects were induced erythema for three times minimal erythema dose (MED) at upper arm of dermatome C6 level. Each experimental group had mechanical pain threshold (MPT), electrical pain threshold (EPT), thermal pain threshold (TPT). Results : This study revealed that we observed that pain thresholds were significantly correlated with each other in pain processing system. The effect of electrical stimulation levels evaluates were shown to be significant differences pain control effect in electrical stimulation group (sensory, motor level electrical stimulation groups) more than indomethacine group, subsensory level and control group. Conclusion : In this study, it was found that the effect of ultraviolet induced erythema of pain control by modulatory electrical stimulation.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1667-1668
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• 2008

There are three main devices such as boiler producing steam, turbine driving generator and generator producing electricity. An electrical generator in power plant is driven and maintained its speed at rated by steam turbine which is coupled into generator directly. Turbine auxiliary devices such as condenser, deaerator, feed water heater, gland steam condenser, pump recirculation equipment, feed water pump, and so on should be operated well so that the steam turbine exert its maximum efficiency. There are many control loop such as hot well level and condenser recirculation, deaerator level, pegging steam pressure, feed water heater level, feed water pump recirculation. In this paper condenser level control and deaerator level control are going to be described.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.10
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• pp.544-554
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• 1999

Multi-level inverters are now receiving widespread interest form the industrial drives for high power variable speed applications. Especially, for the high power variable speed applications, a diode clamped multi-level inverter has been widely used. However, it has the inherent problem that the voltage of the link capacitors fluctuates. This paper describes a voltage control scheme effectively to suppress the DC-link potential fluctuation for a diode clamped four-level inverter. The current to flow from/into the each link capacitor is analyzed and the operation limit is obtained when a conventional SVPWM is used. To overcome the operation limit, a modified carrier-based SVPWM is proposed. Various simulation and experiment results are presented to verify the proposed voltage control scheme for DC-link voltage balancing.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.739-747
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• 2019

As the research for analyzing the awareness and the performance level for infection control of radiological technologists working at the clinic located in Gyoungsangnam province, this study was conducted to provide the basic education data of infection control for radiological technologist who works in the clinic. During July 14, 2014 to March 31, 2015, after we sent out a total of 150 questionnaires for the survey to radiological technologists working at the clinic located in Gyoungsangnam province, 131 questionnaires suitable for research were analysis by using SPSS 18.0 statistical analysis software. As the infection control factors, a total of 60 items about the awareness and the performance level for infection control (12 items for infection control characteristics included) were analyzed. Descriptive statistics, t-test, ANOVA, correlation, and regression analysis were performed based on the general characteristics of the study subjects. Regarding the awareness factor for infection control, the total awareness level was high as $4.15{\pm}.05$ and the total performance level was also high as $4.05{\pm}.05$. Through these results, although the performance level was slightly lower than awareness level, the level of infection control of the radiological technologists working at the clinics located in Gyeongnam was analyzed to be relatively high. The infection control of the clinic's radiological technologist should be carried out through the continuous infection education and prevention activities of the hospital staff, and radiological technologist working in clinics should also be positioned as specialists in infection control.