• Journal of Korean Academy of Nursing
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• v.28 no.1
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• pp.117-131
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• 1998

The purpose of this study was to develop a critical pathway for case management for patients who have received Coronary Artery Bypass Graft (CABG) because of Ischemic Heart Disease(IHD) which is a factor of rising medical expenses. For this study. a conceptual framework was developed through a review of the literature including six critical pathways which are currently being used in USA. In order to identify the overall service contents required by these patients and to draw up a preliminary critical pathway, 30 cases of medical records of patients who had CABG because of IHD between January, 1995 to June. 1996 at the Cardiovascular Center of Yonsei Medical Center in Seoul were analyzed. An expert validity test was done for the preliminary critical pathway and clinical validity test was also done using seven IHD patients with CABG between November 11 and 23, 1996. After these processes. the final critical pathway was developed. The results of this study are summarized as follows : 1. The vertical axis of the critical pathway includes the following eight items : tests, nutrition, medications, consultations, activity, assessments, treatments, education discharge planning and the horizontal axis includes the time from the start of hospitalization to discharge. 2. Analysis of the 30 medical records indicated that the average length of stay was 20.2days with the average length of stay from hospitalization day to operation day being 6.2 days, and the average length of stay from operation day to discharge day was 13. 9 days. Analysis of the service contents showed that the horizontal axis of the preliminary critical pathway was set from hospitalization to the 14th post operation day and the vertical axis was set to include eight items, the contents which ought to have occurred, according to the time frames of the horizontal axis. 3. As a result of the experts validity, it was found that among the total of 571 items. there was over 83% agreement for 482 items, less than 83% for 89 items, which were then deleted and a revision of the critical pathway was done. 4. A clinical validity test was done using seven IHD patients with CABG. During the process, three patients were deleted because they were out of the criteria the investigator set. Finally, four patients were used. The result of study indicated that only one patient was discharged on the tenth post operation day, which was one day later than the expected day. Three patients were discharged later than the expected day from three days to nine days. All the cases progressed on schedule until the operation day and the first post operation day, but from the second post operation days, there were differences between the critical pathway and the actual practice. The differences came from tests, assessments, and treatments. 5. On the basis of the results of the clinical validity test. the following revisions in the final critical pathway were made : the transfer from ICU to step down ward would be the second post operation day, and the transfer to a general ward, the fifth post operation day, for patients who complained of lack of sleep from the fifth post operation day to discharge, a sleeping pill would be prescribed, skin observations would be performed routinely from immediately after the operation until the third post operation day, and would continue if there was a sign of skin injury on the fourth post operation day, and assessment of chest pain would be done from the third post operation day, and the “stairs climbing” item, expected to be done on the ninth post operation day would be deleted. In conclusion, this critical pathway is partially applicable to the care of patients with CABG but there are some parts needed to be further investigated.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.3 s.18
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• pp.29-39
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• 2005

The objective of this study is to analyze the relation of critical duration according to hydrologic characteristics in urban areas. RRL, ILLUDAS, SWMM, and SMADA urban runoff models were applied to the Seongnae and Banpo watershed and experiment area of the Dong-Eui University. Also, hydrologic characteristics such as temporal pattern of rainfall, rainfall intensity formula, antecedent moisture condition, return period, and urban runoff model were used to simulate the critical duration of the test areas. The results of this study are as follows; (1) The type of temporal pattern of rainfall which causes maximum peak discharge in urban area has resulted in Huff's 4th quartile distribution. (2) The critical duration in urban areas were not influenced by hydrological factors except urban runoff model. (3) Peak discharge and critical duration in urban areas were influenced by the urban runoff model, and the SWMM model using Huff's 4th quartile distribution shows maximum critical duration.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.2127-2132
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• 2003

A computational study is performed to better understand the choke phenomenon of unsteady gas flow through a critical nozzle. The axisymmetric, unsteady, compressible, Navier-Stokes equations are solved using a finite volume method. In order to simulate the effects of back pressure fluctuations on the critical nozzle flow, a forced sinusoidal pressure wave is assumed downstream the exit of the critical nozzle. It's frequency is 20kHz and amplitude is varied below 15% of time-mean back pressure. The results obtained show that for low Reynolds numbers, the unsteady effects of the pressure fluctuations can propagate upstream of the throat of critical nozzle, and thereby giving rise to applicable fluctuations of mass flow through the critical nozzle. The effect of the amplitude of the excited pressure fluctuations on the choke phenomenon is discussed in details.

• Journal of Sensor Science and Technology
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• v.30 no.2
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• pp.105-108
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• 2021

Detection and localization of partial discharge are considered critical techniques for estimating the lifetimes of power cables. High-frequency current transformers (HFCTs) are commonly used for the detection of partial discharge in high-voltage alternating current (HVAC) power cables; however, their applicability is compromised by the limitations of the installation locations. HFCTs are typically installed in cable terminals or insulation joint boxes because HVACs induce strong time-varying magnetic fields around the cables, saturating the ferromagnetic materials in the HFCTs. Therefore, partial discharges near the installation locations can be detected. In this study, the feasibility of partial discharge detection using a HFCT was investigated for high-voltage direct current (HVDC) cables. We demonstrated that the HFCT could be installed at any location in the HVDC power cable to monitor partial discharge along the entire cable length. Furthermore, we showed that the HFCT could detect the location of partial discharge with high accuracy.

• Journal of Korean Critical Care Nursing
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• v.11 no.3
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• pp.45-57
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• 2018

Purpose : This study was performed to identify the influencing factors of unplanned intensive care unit (ICU) readmission. Methods : The study adopted a Rretrospective case control cohort design. Data were collected from the electronic medical records of 844 patients who had been discharged from the ICUs of a university hospital in Incheon from June 2014 to December 2014. Results : The study found the unplanned ICU readmission rate was to be 6.4%(n=54). From the univariate analysis revealed that, major symptoms at $1^{st}$ ICU admission, severity at $1^{st}$ ICU admission (CPSCS and APACHE II), duration of applying ventilator application during $1^{st}$ ICU admission, severity at $1^{st}$ discharge from ICU (CPSCS, APACHE II, and GCS), and application of $FiO_2$ with oxygen therapy, implementation of sputum expectoration methods, and length of stay of ICU at $1^{st}$ ICU discharge were appeared to be significant; further, decision tree model analysis revealed that while only 4 variables (sputum expectoration methods, length of stay of ICU, $FiO_2$ with oxygen therapy at $1^{st}$ ICU discharge, and major symptoms at $1^{st}$ ICU admission) were shown to be significant. Conclusions : Since sputum expectoration method was the most important factor to predictor of unplanned ICU readmission, a assessment tool for the patients' capability of sputum expectoration needs to should be developed and implemented, and standardized ICU discharge criteria, including the factors identified from the by empirical evidences, might should be developed to decrease the unplanned ICU readmission rate.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.4
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• pp.226-231
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• 2000

In this paper, we present new method to analyze the space charge effect on the electrical characteristics in polymer. It is new measurement system and analysis method that have not reported yet. By using this measurement system, we make observation to space charge accumulated on the surface of polymer at AC voltage, so it is examined to verify the correlation of space charge and partial discharge(PD). In the result of experiment, it can be known that PD pattern is related more closely to space charge accumulated on the surface of polymer than in the inner part, and applied voltage in the air is ruled by this dynamic partial discharge. Also, above critical voltage, the space charge accumulated on the surface of polymer have no effect to the magnitude of PD and the applied voltage in the air. It has been known that the electric power of the dissolution system is proportioned to the frequency and the magnitude of applied voltage, but we can know by this result of the experiment that the efficiency of the dissolution is not related to the rise of voltage above critical voltage.

• Journal of the Korean Society of Safety
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• v.24 no.1
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• pp.89-94
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• 2009

The purpose of this study is to estimate the critical flood discharge and flash flood trigger rainfall for alarm system providing for a flash flood in mountainous area. The flash flood need non-linear approaching method, because rainfall-runoff is nonlinear and it is difficult to explain the existing linear rainfall-runoff. Hydrological characteristics would be utilized to apply such as hydrologic modelling or basin management. This study was effectively estimated a topographic characteristic factor of basin using the GIS. Especially, decided stream order using GIS at stream order decision that is important for input variable of GCIUH. A flash floods defined as a flood which follows shortly after a heavy or excessive rainfall event, with a few hours. In this study, we gave a definition that a critical flood for alarm is the flood when valley depth judging dangerous depth is over 0.5m depth from the bottom of channel. Result that calculate threshold discharge to use GCIUH, at the Mureung valley basin, flash flood trigger rainfall was 16.34mm in the first 20minutes when the threshold discharge was $14.54m^3/sec$.

• Tribology and Lubricants
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• v.16 no.3
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• pp.157-165
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• 2000

A discharge free Electro-Rheological Squeeze Film Damper (ER-SFD) with predetermined-clearances at leakage ends can inherently eliminate electric discharge problems while still supplying stable leakage control. Test results show that the damping force of the slotted-ring ER-SFD is mainly affected by electric voltage, oil supply pressure, position of the damper and ratio of effective surface area of slotted-rings. As the supply voltage is larger, the amplitudes of both slotted ER-SFD and rotor are decreased at first and second critical speeds. The influence of the oil supply pressure and the effective surface area ratio was shown mainly near the first critical speed. The effective surface area ratio of slotted-rings influences the reduction of flexible rotor vibration. As a result, experimental results confirm that the slotted-ring ER-SFD satisfactorily controls the flexible rotor vibration, while eliminates the inherent electric discharge problems in conventional ER-SFDs.

• Journal of Korean Critical Care Nursing
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• v.12 no.1
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• pp.22-35
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• 2019

Purpose : This study was to determine the levels of environmental stressor, posttraumatic stress disorder, and quality of life in intensive care units (ICU) survivors after intensive care, and to explore the factors affecting posttraumatic stress disorder and quality of life. Methods: With a longitudinal survey design, data were collected from 116 patients who were discharged from the ICU of a university hospital. The environmental stressor, posttraumatic stress disorder, and quality of life were measured immediately following and 1 month after the ICU discharge. Results: Of all the subjects, 16.4% experienced posttraumatic stress disorder after discharge. Multiple regression analysis revealed that ICU environmental stressors, experience of ICU readmission, using psychotropic drugs and narcotic analgesics, and ICU admission after surgery or cardiac intervention accounted for 22.2% of posttraumatic stress disorder. Posttraumatic stress disorder and sedation status when entering ICU accounted for 28.3% of the quality of life 1 month after ICU discharge. Conclusion: Nursing interventions focused on ICU environmental stressors would not only reduce environmental stress but also contribute to the reduction of posttraumatic stress disorder and later improvement of quality of life.

• Nuclear Engineering and Technology
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• v.52 no.4
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• pp.755-763
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• 2020

The critical flow phenomenon has been studied because of its significant effect for design basis accidents in nuclear power plants. Transition points from thermal non-equilibrium to equilibrium are different according to the geometric effect on the critical flow. This study evaluates the uncertainty parameters of the critical flow model for analysis of DBA (Design Basis Accident) with the MARS-KS (Multi-dimensional Analysis for Reactor Safety-KINS Standard) code used as an independent regulatory assessment. The uncertainty of the critical flow model is represented by three parameters including the thermal non-equilibrium factor, discharge coefficient, and length to diameter (L/D) ratio, and their ranges are determined using large-scale Marviken test data. The uncertainty range of the thermal non-equilibrium factor is updated by the MCDA (Model Calibration through Data Assimilation) method. The updated uncertainty range is confirmed using an LBLOCA (Large Break Loss of Coolant Accident) experiment in the LOFT (Loss of Fluid Test) facility. The uncertainty ranges are also used to calculate an LBLOCA of the APR (Advanced Power Reactor) 1400 NPP (Nuclear Power Plants), focusing on the effect of the PCT (Peak Cladding Temperature). The results reveal that break flow is strongly dependent on the degree of the thermal non-equilibrium state in a ruptured pipe with a small L/D ratio. Moreover, this study provides the method to handle the thermal non-equilibrium factor, discharge coefficient, and length to diameter (L/D) ratio in the system code.