• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2002.02a
• /
• pp.245-248
• /
• 2002

One dimensional conduction equation is solved by finite difference method, to analyse the stability of Au/YBCO film deposited on a sapphire substrate. Jolue heat is included in the case of current sharing state. The analysis shows the quench and recovery of superconductor depending on the amount of thermal disturbance release on the center surface of superconductor. The critical disturbance energies for different filling factor and operating current are calculated.

• Progress in Superconductivity and Cryogenics
• /
• v.4 no.2
• /
• pp.27-30
• /
• 2002

One dimensional conduction equation is solved by finite difference method, to analyse the stability of Au/YBCO film deposited on a sapphire substrate. Joule heat is included in the case of current sharing state. The analysis shows the quench and recovery of superconductor depending on the amount of thermal disturbance release on the center surface of superconductor. The critical disturbance energies for different filling factor and operating current are calculated.

• Proceedings of the IEEK Conference
• /
• 2003.07c
• /
• pp.2807-2810
• /
• 2003

In this paper, we propose a fuzzy control method for improving the control performance by automatically tuning the scaling factor. The proposed method is that automatically tune the input scaling factor and the output scaling factor of fuzzy logic system through neural network. Used neural network is ADALINE (ADAptive Linear NEron) neural network with delayed input. ADALINE neural network has simple construct, superior learning capacity and small computation time. In order to verify the effectiveness of the proposed control method, we performed simulation. The results showed that the proposed control method improves considerably on the environment of the disturbance.

• Journal of Korean Clinical Nursing Research
• /
• v.19 no.2
• /
• pp.285-297
• /
• 2013

Purpose: This study was conducted to investigate the differences in sleep disturbance, stress, self-efficacy and depression by fatigue level and to identify the factors influencing fatigue in hemodialysis patients. Methods: This study used a cross-sectional design and the subjects were 195 patients undergoing hemodialysis in a local unit. Data were collected using a structured questionnaire and medical records from June to August 2012. The data were analyzed using descriptive statistics, independent t-test, one way ANOVA, $Scheff{\grave{e}}$ test, and Pearson's correlation coefficients. Also a multiple regression analysis was used to assess the independent association between fatigue status and indices of sleep disturbance, stress, self-efficacy and depression. Results: A total of 99 (50.8%) subjects experienced a high level of fatigue and 96 (49.2%) experienced a low level of fatigue. There were significant differences in the levels of sleep disturbance, stress, self-efficacy and depression between the two groups. Fatigue was significantly correlated to sleep disturbance, stress, self-efficacy and depression. The most important factor related to fatigue was stress, followed by sleep disturbance. These factors explained about 37% of fatigue of the respondents. Conclusion: The results of this study showed that sleep disturbance and stress were significant predictors of fatigue in hemodialysis patients. Possible interventions for minimizing fatigue in patients undergoing long-term hemodialysis should be aimed to manage the known contributing factors.

• Journal of Korean Academy of Nursing
• /
• v.27 no.3
• /
• pp.588-600
• /
• 1997

Postpartum depression is one of the most serious problems in maternal health because it affects not only the mother but also her family. Postpartum depression disturbs the maternal-infant interaction and attachment. However, most postpartum depression patients ignore this problem and do not seek treatment. Many clinicians and researchers realiza there is a need to develop a postpartum depression scale. Thus, this study has been designed to development of a postpartum depression scale. Data were collected through a survey over a period of three months. Subjects who participated in the study were 167 Korean mothers in their postpartum period. The author used a convenience sampling method. The analysis of the data was done with SPSS PC/sup ＋/ for descriptive statistics, item analysis and factor analysis. Initially 62 items were generated from the interview data of eight postpartum depression patients and from a literature review. This preliminary scale was analyzed for reliability and validity. The results of this analysis are as follows. 1. Initially 62 items were analyzed through the Index of Content Validity(CVI) and 48 items were selected. 2. Seven factors were extracted through the principal component analysis, and these contributed 61% of the variance in the total score. Finally 46 items in the scale loaded .41∼ .84 on one of seven factors. 3. Each factor was labeled. Factor 1 was labeled 'emotional phenomena-emotional upset' and included 13 items, factor 2 was labeled' cognitive phenomena-self concept disturbance' and included seven items, factor 3 was labeled 'relationship to baby-negative feeling' and included six items, factor 4 was labeled 'relationship to baby- overload' and included eight items, factor 5 was labeled 'negative maternal identity' and included five items, factor 6 was labeled 'biophysiological phenomena-disturbance of physical functioning' and included four items, and factor 7 was labeled' interpersonal relationship phenomena-blamed others' and included three items. 4. Cronbach Coefficient Alpha for internal consistency was .95 for the total 46 items. Finally, the author suggests that this scale could be adequately applied in assessing the postpartum depression of mothers during the postpartum period. The results of this study can contribute to designing an appropriate postpartum depression prevention strategy.

• The KSFM Journal of Fluid Machinery
• /
• v.15 no.4
• /
• pp.12-18
• /
• 2012

This study was performed to found out the deviations for clamp-on type ultrasonic flowmeter installed in downstream of valves. It was selected three types of two-path flowmeter mainly used for K-water as test. Experiment carried out to confirmed characteristics of deviation depending on the sensor location, straight pipe length and maker for 1-path, 2-path and 4-path combined 2-path flowmeter. It was selected two kinds of valves with 100 % and 50 % opening, butterfly valves and gate valves, for flow disturbance factor. Finally, we suggested number of sensors by maker, straight pipe length and installed location of sensors satisfying the tolerance depending on the experiment results.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.699-703
• /
• 2004

The autopilot system targets decreasing labor, working environment, service safety security and elevation of service efficiency. Ultimate purpose is minimizing number of crew for guarantee economical efficiency of shipping service. Recently, being achieving research about Course Keeping Control, Track Keeping Control, Roll-Rudder Stabilization, Dynamic ship Positioning and Automatic Mooring Control etc. which compensate nonlinear characteristic using optimizing control technique. And application research is progressing using real ship on actual field. Relation of Rudder angle which adjusted by Steering Machine and ship-heading angle are non-linear. And, Load Condition of ship acts as non-linear element that influence to Parameter of ship. Also, because the speed of a current and direction of waves, velocity and quantity of wind etc. that id disturbance act in non-linear form, become factor who make service of shipping painfully. Therefore, service system of shipping requires robust control algorithm that can overcome nonlinearity. In this paper, Using GA algorithm,design autopilot system of ship that could overcome the non-linear factor of ship and disturbance and examined result through simulation.

• Journal of the Korean Geotechnical Society
• /
• v.15 no.4
• /
• pp.133-152
• /
• 1999

The cyclic triaxial test was carried out to research liquefaction characteristics and sample disturbance effects of silty sand soils at the west coast in Korea. First, liquefaction in silty sand was generated when axial strain approached to $\pm10%$ of strain and behavior of pore pressure was similar to the formula suggested by Seed, Martin, and Lysmer(1975). Also, it was found that dilatancy was generated at failure. Secondly, the liquefaction evaluation methods suggested by many researchers were carried out and the results were compared. In these methods the weak depth in liquefaction was similar and the method carried out by cyclic triaxial test on remolded sample showed the least safety factor. Thirdly the stress ratio by cyclic triaxial test was compared with that obtained from SPT N-value as a kind of empirical methods. It was found that the effect of sample disturbance was relatively small when SPT N-value was less than 20, but there were large differences in safety factor and resistance of liquefaction in soil by the effects of disturbance and remolding when SPT N-value was more than 20.

• Journal of Institute of Control, Robotics and Systems
• /
• v.8 no.12
• /
• pp.1004-1013
• /
• 2002

A multirate state feedback control (MRSFC) method is proposed for systems sensitive to disturbance and noise based on the multirate estimator design using current estimator. MRSFC updates the controller output slower than the measurement sampling fiequency of system output by a lifting factor $R=T_c/T_s$ The closed-loop MRSFC system is less sensitive to disturbance and noise due to filtering effect than the conventional single-rate control system The multirate estimator gain can be obtained by solving a conventional pole placement problem such that MRSFC has the same spectrum of eigenvalues in the s-plane as the single-rate control. We applied the proposed multirate state feedback controller to a galvanometer servo system Simulation and experimental results show that settling and tracking performances are improved compared with a conventional single-rate pole placement control (PPC).

• Journal of The Korean Society of Agricultural Engineers
• /
• v.51 no.5
• /
• pp.51-58
• /
• 2009

The total recovery ratio test on undisturbed clay soil sampling in the field and the finite element method analysis on modified static state of penetration process were conducted for the purpose of deciding the most important factor among the shape factors of thin wall tube. The adhesion between tube wall and soil did not decrease although internal clearance ratio of tube increased within the little change of tube area ratio. The most part of disturbance occurred in the tip of sampling tube during the penetration. The longitudinal displacement was larger than the lateral displacement because soil was confined laterally after being entered into tube, and also the longitudinal displacement was larger in the upper part of the sample tube than in the lower part.