• Advances in aircraft and spacecraft science
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• v.10 no.4
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• pp.369-391
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• 2023

In our research we have offered a solid solution for aeronautical analysis. which can guarantee the asymptotic stability of coupled nonlinear facilities. According to the theoretical solutions and methods presented, the engine of this aircraft is a small high-bypass turbofan engine. using the non-linear aero-motor control approach and this paper focuses on the power management function of the aero-motor control system. These include static controls and transient controls. A mathematical model of the high-bypass-ratio two-spool unmixed-flow aeroengine was developed through a set of nonlinear dynamic equations verified by experimental data. A single actuator using the displacement method is designed to maintain a certain level of thrust under steady-state conditions. and maintains repeatable performance during transient operation from the requested thrust phase to the next. A single controller can compensate for the effects of noise and harmonic noise at many performance points. And the dynamic performance of a single controller is satisfactory during the transient. for fairness Numerical and computer experiments are described in the perfection of the methods we offer in research.

• Journal of Korean Critical Care Nursing
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• v.1 no.1
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• pp.33-45
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• 2008

Purpose: Patients who underwent a coronary artery bypass graft surgery(CABG) experienced the unpleasant emotions and discomfort when their chest tube was removed. The purpose of this study was to evaluate the effects of cold therapy on pain related to chest tube removal(CTR) in CABG patients. Methods: Fifty adult patients undergoing CABG were recruited in a prospective, double blinded study. Subjects were divided into the experimental group and the control group considering their sex and age. The pretest data were obtained 20 minutes before CTR. Patients in the experimental group, received cold therapy for 10 minutes before CTR. Pain sense and intensity were determined immediately after CTR and at 10 minutes after CTR. Results: The total score of pain sense immediately after CTR of the experimental group was significantly lower than that of the control group(t=-3.703, p=.003). And scores of pain intensity immediately after CTR in the experimental group were significantly lower than that of the control group(t=-3.073, p=.001). But, there was no significant difference in the score of pain intensity 10 minutes after CTR between the experimental and the control group(t=1.759, p=.085). Conclusion: The cold therapy would be recommended as an effective and nonpharmacologic nursing intervention for relieving pain in patients undergoing CTR.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.1
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• pp.1-8
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• 2012

Recently, the needs of system performances such as working speed and processing accuracy in machine tools have been increased. Especially, the speed increment generates harmful heat at both moving part of the machine tools and handicrafts. The heat is a main drawback to progress accuracy of the processing. Hence, a cooler system to control temperature is inevitable for the machine tools. In general, two representative control schemes, hot-gas bypass and variable speed control of a compressor, have been adopted in the water cooler system. In this paper, comparisons of system performances according to the control schemes in a cooler for machine tools were conducted in detail. Each proportional-integral feedback controller for the two different control systems is designed. The system performances, especially the temperature control accuracy and coefficient of performance which is a criterion of energy saving, were mainly analyzed through various experiments using 1RT water cooler system with different two types of control scheme. These evaluations will provide useful information to choose suitable water cooler system for the engineers who design controllers of the cooler system for machine tools.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.2
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• pp.111-119
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• 2011

Recently, the performances of speed and accuracy are enhanced in machine tools. The high speed of the machine tools usually causes harmful thermal displacements on the objects. To reduce the thermal displacements, machine tools generally adopt oil coolers with precise temperature control function. This study aims at precise control of oil outlet temperature in the oil coolers with hot-gas bypass manner based on PI control logic. The control system was designed for obtaining steady state error within ${\pm}0.1^{\circ}C$ and maximum overshoot with 0.8% even though abrupt disturbances are added to the system. We showed that the PI gains could be easily decided by numerical simulations using practical transfer function which got experiments. Also, transient characteristics could be improved significantly by reflecting the inlet temperature of an evaporator to the output of a controller feedforwardly considering periodic abrupt disturbances. Through some experiments, excellent control performances were established by the suggested control.

• Journal of Korean Clinical Nursing Research
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• v.14 no.1
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• pp.25-32
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• 2008

Purpose: The purpose of this study was to examine quality of life with patients in 12 months after coronary artery bypass graft surgery, compared with general population. Method: A cross-sectional comparative study was designed. Study participants were 90 adults who had undergone CABG surgery (n=45) in experimental group and general population (n=45) in control group. The subjects were asked the questionnaire (SF-36, Short Form-36) regarding the quality of life. The data were analyzed by the SPSS 13.0 program including frequency, percentage, $x^2$ test, t-test and One-Way ANOVA. Results: There were no significant differences in the quality of life between two groups including physical functioning (t=-.938, p=.351), role-physical limitation (t=-.322, p=.748), bodily pain (t=-.938, p=.351), general health (t=-.1418, p=.888), vitality (t=-.816, p=.417), social functioning (t=.720, p=.474), role-emotional limitation (t=-.710, p=.479), mental health (t=-.431, p=.667). Conclusion: Even though patients in experimental group had operation experience, the quality of life examined on the time of 1 year after bypass surgery is similar in that of general population. We suggest the study change the design as examination of quality of life before and after coronary artery bypass graft surgery.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.1
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• pp.1-13
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• 1997

The key point that guarantees the durability of the ceramic monolith filter is to lower peak temperature and temperature gradient inside filter during regeneration. The control of the exhaust gas flow rate into the filter, by the bypass technique of the exhaust gas, enables the gas temperature in filter to be constant for regeneration. A couple of methods, which are the ON/OFF and PID control of the bypass valve, were used for feedback control of the gas temperature. These techniques showed that the ceramic filter was regenerated perfectly under the peak temperature and peak temperature gradient limitations for durability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.5 s.248
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• pp.550-559
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• 2006

This paper presents designs and performance investigations of two bypass-type MR (magneto-rheological) shock dampers for high impulsive force systems, one of which is with single rod and the other with double rod. First of all, on the basis of the Bingham properties of the MR fluid and the magnetic field analysis of the magnetic circuit, the MR shock dampers are designed and manufactured. After experimental investigations on their magnetic field-dependent damping forces and responses characteristics, dynamic models of the proposed dampers are formulated and compared. Then, a simple 1 degree-of-freedom mass-drop system is constructed, and the effective and practical control algorithm is designed by considering dynamic characteristics of the shock control system. The shock control performances of the proposed MR shock dampers are verified through the comparison study of experiment results with simulation ones.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.3
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• pp.376-385
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• 2008

Twenty lactating crossbred cows yielding 10 to 15 litres of milk daily during mid lactation were selected and divided into four groups of five animals to assess the effect of feeding calcium soaps of palm oil fatty acids (bypass fat) on milk yield, milk composition and nutrient utilization in lactating crossbred cows. The animals in groups 1 (control), 2, 3 and 4 were fed concentrate mixture containing 0 (no bypass fat), 2, 4 and 6% bypass fat, respectively. The average daily dry matter consumption in the various groups ranged from 13.1 to 13.6 kg and showed no significant difference among treatment groups. There was no significant difference among different groups in digestibility of DM, OM, CP and CF, however, ether extract digestibility in cows of groups 2 and 4 was significantly (p<0.05) higher than the control group. The average milk yields of the cows in group 3 (4% bypass fat) showed a significantly (p<0.05) higher value than cows of groups 1 and 2. Similarly, a significant (p<0.05) increase in fat yield, 4% FCM yield and SNF yield was observed for the cows in group 3 (4% bypass fat). The milk composition in terms of total solids, fat, lactose, protein, solids-not-fat and ash percentage showed a varying response and bypass fat feeding did not have any effect on milk composition of cows in different groups. The gross and net energetic efficiency of milk production ranged from 23.6 to 27.5% and 37.1 to 44.4%, respectively, and showed no significant difference among different treatment groups. The gross and net efficiency of nitrogen utilization for milk production ranged from 24.0 to 28.7% and 37.2 to 43.5%, respectively, and no significant difference was noted among different treatment groups. The supplementation with calcium salts of palm oil fatty acid reduced the proportion of caproic, caprylic and capric acids and significantly (p<0.01) increased the concentration of palmitic, oleic, stearic, linoleic and linolenic acids in milk fat with increase in level of bypass fat supplementation. It was concluded that incorporation of calcium salts of palm oil fatty acids at a 4% level in the concentrate mixture of lactating crossbred cows improved the milk production and milk quality in terms of polyunsaturated fatty acids without affecting the digestibility of nutrients.

• Journal of Chest Surgery
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• v.40 no.4 s.273
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• pp.273-279
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• 2007

Background: We evaluate the efficacy of ultra-hydrophilic coated bypass circuits in comparison with uncoated bypass circuits in a porcine cardiopulmonary bypass model. Material and Method: Normothermic cardiopulmonary bypass was peformed in 10 anesthetized pigs via the left atrium and ascending aorta with a centrifugal biopump. Ultra-hydrophilic coated bypass circuits wore used in 5 pigs (the study group) and uncoated bypass circuits were used for the control group. Platelet counts and platelet aggregation tests were peformed. The thrombin-antithrombin(TAT) complex level and total protein level were evaluated. Result: There were no significant changes En the platelet counts and aggregation ability of both groups. The TAT complex levels were not different between the two groups. The total protein level was significantly lower in the control group after cessation of cardiopulmonary bypass. Conclusion: The clinical effects of ultra-hydrophilic coating circuits were not remarkable, in terms of reducing inflammatory reaction and protection of platelet function. However, the effect of protection for blood protein adsorption might be acceptable.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.3
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• pp.205-211
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• 2013

Recently, the needs of system performances such as working speed and processing accuracy in machine tools have been increased. Especially, the working speed increment generates harmful heat at both moving part of the machine tools and handicrafts. The heat is a main drawback to progress accuracy of the processing. Hence, a oil cooler to control temperature is inevitable for the machine tools. In general, two representative control schemes, hot-gas bypass and variable speed control of a compressor, have been adopted in the oil cooler system. This paper deals with design and implementation method of fuzzy controller for obtaining precise temperature characteristic of HB oil cooler system in machine tools. The opening angle of an electronic expansion valve are controlled to keep reference value and room temperature of temperature at oil outlet. Especially, the fuzzy controller is added to suppress temperature fluctuation under abrupt disturbances. Through some experiments, the suggested method can control the target temperature within steady state error of ${\pm}0.22^{\circ}C$.