• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.3
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• pp.186-195
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• 2000

In this paper, partial discharge (PD) measurement was performed to evaluate the quality of the cable joint and termination constructions. The resistive coupling technique for PD detection using resistivity of semiconducting layer of the cable in the accessories, such as joints and terminations. With high frequency PD (HEPD) measurement, an excellent sensitivity below 20pC could be achieved under unshielded condition. The localization of the defects in the accessories could be identified. During heating cycle, PDs were monitored and analyzed. At that time, the PDs were dependent on the temperature of the heating cycle and showed cyclic behaviors, which were attributed to local delamination of the interfaces, between epoxy unit and stress relief cone(SRC) and between SRC and cable, due to the difference of thermal expansion. As a conclusion, HFPD measurement technique was proven to be an effective diagnostic method for qualification of extra high voltage (EHV) cable accessories. With this technique, the optimal design of the components of the accessories could be verified not only in an early stage but also under operating condition. This technique would result in the improvement of the reliability of the EHV cable accessories.

• Journal of Electrical Engineering and Technology
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• v.11 no.3
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• pp.683-689
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• 2016

Most outdoor solid insulators may suffer from surface degradations due to non-stationary currents that flow on the insulator surface. These currents may be classified as leakage, discharge and tracking currents due to their disturbing potencies respectively. The magnitude of these currents depends on the degree of the contamination of surface. The leakage signals are followed by discharge signals and tracking signals which are capable of forming carbonized tracking paths on the surface between high voltage and earth contacts (surface tracking). Surface tracking is one of the most breakdown mechanisms observed on the solid insulators, especially polymers which may cause severely reduced lifetime. In this study the degradations observed on polyester resin based insulators are investigated according to the IEC 587 Inclined Plane Test Standard. The signals are monitored and recorded during tests until surface tracking initiated. In order to prevent total breakdown of an insulator, early detection of tracking signals is vital. Continuous Wavelet Transform (CWT) is proposed for classification of signals and their energy levels observed on the surface. The application of CWT for processing and classification of the surface signals which are prone to display high frequency oscillations can facilitate real time monitoring of the system for diagnosis.

• Journal of Electrical Engineering and Technology
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• v.4 no.1
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• pp.123-130
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• 2009

The partial discharge (PD) measurement is a very effective method to assess the winding insulation condition of high-voltage machines, since most of the insulation failure processes are directly or indirectly caused by PD. On-line PD measurements, which can detect insulation defects of winding in the early stages on rotating machines in operation, have been accepted as the most important technique. The epoxy mica capacitive coupler is currently and extensively used for on-line detection of PD pulses of high-voltage rotating machines. To evaluate the feasibility of developing a capacitive coupler that is easier to manufacture at a lower cost compared to epoxy mica couplers, a 100pF capacitive coupler made of ceramic material is designed, fabricated and tested for on-line PD measurements of 23 kV electrical machines. A series of electrical tests and accelerated aging tests are performed on the ceramic coupler to evaluate the performance requirements, long-term reliability and thermal stability for in field application. The test results show that the newly developed ceramic coupler provides equal and improved performance at a lower cost compared to epoxy mica couplers, and estimated voltage life is anticipated to surpass 100 years.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.12a
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• pp.75-78
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• 2006

An external electrode fluorescent lamps (EEFLs) have the advantage of a long lifetime in the early stages of the study on plasma discharge, interest in the lamp continues. Studies on the operation of external electrode fluorescent lamps have focused mainlyon its use of a type of high frequency (MHz). By performing high brightness using a square wave operation method with the low frequency below 100kHz, which is applied to a narrowed tube type lamp that has several mm of lamp diameter, an EEFL presented the possibility of using it as a light source for backlights. However, because an EEFL generates plasma using wall charges, which considers the impedance characteristics of glass based on the structural principle in discharge, it can be significantly affected by frequency. Thus, this study verifies the change in the characteristics of electromagnetic fields according to the change in frequency through a Maxwell's electromagnetic field simulation and examines the relationship between the change in the EEFL frequency and brightness by measuring the optical. characteristics. In addition, the characteristics of the transformation of energy orbits were verified by investigating the characteristics of the wavelength according to the change in frequency through the OES.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.499-502
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• 2004

In order to detect of insulation problems an early, transformer has to be performed the several tests. The ac current and tan6 of transformer winding insulation were investigated by Schering bridge. Partial discharge(PD) tests are used to evaluate the insulation condition of transformer. The moisture content measurement was conducted using RVM(recovery voltage meter). The RVM test can show that the problem is affecting the paper insulation of transformer. The value of moisture content was 2.3% in main transformer. The insulations of four transformers were judged to be in good condition.

• Clinical and Experimental Pediatrics
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• v.65 no.1
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• pp.1-9
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• 2022

With advancements in neonatal care and nutrition, the postnatal growth of preterm infants has improved; however, it remains an issue. Accurate assessments of growth using a standardized reference are needed to interpret the intrauterine and postnatal growth patterns of preterm infants. Growth in the earlier periods of life can contribute to later outcomes, and the refinement of postnatal growth failure is needed to optimize outcomes. Catch-up growth occurs mainly before discharge and until 24 months of age, and very low birth weight infants in Korea achieve retarded growth later in life. Knowing an infant's perinatal history, reducing morbidity rates during admission, and performing regular monitoring after discharge are required. Preterm infants with a lower birth weight or who were small for gestational age are at increased risk of poor neurodevelopmental outcomes. Furthermore, poor postnatal growth is predictive of adverse neurodevelopmental outcomes. Careful monitoring and early intervention will contribute to better development outcomes and national public health improvements.

• Korean Journal of Biological Psychiatry
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• v.20 no.4
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• pp.179-186
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• 2013

Objectives This study is designed to compare the clinical characteristics of patients with early onset schizophrenia to those of adult onset schizophrenia patients in first episode. Methods Authors reviewed medical records of 16 early-onset schizophrenia patients and 22 adult-onset schizophrenia patients who had been admitted in the psychiatric ward and diagnosed as schizophrenia according to Diagnostic and Statistical Manual of Mental Disorders, fourth Edition (DSM-IV) at Eulji University Hospital during 2004-2008. Socio-demographic data and clinical characteristics such as duration between onset and active phase, number of significant positive and negative symptoms, positive and negative symptom scores of Positive and Negative Syndrome Scale (PANSS), Clinical Global Impression-Severity (CGI-S) scores, duration from onset to admission, duration of admission, and equivalent dose of antipsychotics were reviewed. These clinical characteristics of early-onset group were compared to those of adult-onset group. Correlation between age of onset and other clinical characteristics was also analyzed. Results Early-onset group showed more insidious onset pattern and had longer duration of hospitalization than adult-onset group. Early onset group also exhibited more negative symptoms, higher negative symptom scores, and higher CGI-S scores than adult-onset group after treatment. However, there were no significant differences in family history of psychosis, positive symptom frequency at discharge and equivalent dose of antipsychotics between two groups. Conclusions This study revealed that patients with early-onset schizophrenia exhibited more insidious onset, more negative symptoms, and more severe symptoms than those with adult-onset schizophrenia after treatment.

• Journal of Korean Neurosurgical Society
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• v.63 no.6
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• pp.757-766
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• 2020

Objective : Spinal epidural abscess (SEA) is a severe and life-threatening disease. Although commonly performed, the effect of timing in surgical treatment on patient outcome is still unclear. With this study, we aim to provide evidence for early surgical treatment in patients with SEA. Methods : Patients treated for SEA in the authors' department between 2007 and 2016 were included for analysis and retrospectively analyzed for basic clinical parameters and outcome. Pre- and postoperative neurological status were assessed using the American Spinal Injury Association Impairment Scale (AIS). The self-reported quality of life (QOL) based on the Short-Form Health Survey 36 (SF-36) was assessed prospectively. Surgery was defined as "early", when performed within 12 hours after admission and "late" when performed thereafter. Conservative therapy was preferred and recommend in patients without neurological deficits and in patients denying surgical intervention. Results : One hundred and twenty-three patients were included in this study. Forty-nine patients (39.8%) underwent early, 47 patients (38.2%) delayed surgery and 27 (21.9%) conservative therapy. No significant differences were observed regarding mean age, sex, diabetes, prior history of spinal infection, and bony destruction. Patients undergoing early surgery revealed a significant better clinical outcome before discharge than patients undergoing late surgery (p=0.001) and conservative therapy. QOL based on SF-36 were significantly better in the early surgery cohort in two of four physical items (physical functioning and bodily pain) and in one of four psychological items (role limitation) after a mean follow-up period of 58 months. Readmission to the hospital and failure of conservative therapy were observed more often in patients undergoing conservative therapy. Conclusion : Our data on both clinical outcome and QOL provide evidence for early surgery within 12 hours after admission in patients with SEA.

• Journal of Korean Medicine Rehabilitation
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• v.24 no.3
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• pp.131-137
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• 2014

Objectives The purpose of this study was to compare the effects of MSAT (Mostion style acuputure treatment) on piriformis muscle regarding leg radiating pain with HIVD of L-SPINE. Methods Forty patients who received inpatient treatment from Febuarary 1 to March 31, 2014 in the Daejon-Jaseng oriental medicine hospital were divided into 2 groups by blocked randomization : Group A (n=20)=routine treatment on HIVD of L-SPINE with MSAT on piriformis muscle and Group B (n=20)=routine treatment on HIVD of L-SPINE (acupuncture, Shinbaro pharmacopuncture, herb medication, chuna treatment and physiotherapy). The MSAT (Mostion style acuputure treatment) on piriformis muscle was administered each day and both groups were received routine treatment each day. Evaluations were made before treatment, after 3 days and 7 days, and before discharge using the NRS (numeric rating scale) and ODI (oswestry disability index). The statistically significance was evaluated by SPSS 18.0 for windows. Results Compared to before treatment, the NRS (numeric rating scale) and ODI (oswestry disability index) of both A and B groups after 3, 7 days and before discharge of treatment significantly decreased (p<0.05). Regarding group comparison, the NRS (numeric rating scale) and ODI (oswestry disability index) of A group was significantly lower than the B group at 3, 7 days, before dischanre (p<0.05). Regarding improvement of the NRS (numeric rating scale) and ODI (oswestry disability index), A group was significantly lower than the B group at 3 day (NRS), 7day (ODI) (p=0.000) but there was no significant difference between the two groups at 7 days (NRS) and before discharge (p>0.05). Conclusions Compared to just routine treatment, the MSAT (Mostion style acuputure treatment) on piriformis muscle significantly improved the NRS (numeric rating scale) and ODI (oswestry disability index) after 3, 7 days, and before discharge. Because early intervention determines the grade of Leg radiating pain with HIVD of L-SPINE, the MSAT (Mostion style acuputure treatment) on piriformisat the early stage will be clinically helpful to patients.

• Clinical and Experimental Pediatrics
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• v.49 no.1
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• pp.6-13
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• 2006

Jaundice is one of the most common gastrointestinal conditions found in neonatal period, and most jaundice is benign. But because of the possibility of bilirubin toxicity, every newborn infants must be examined to identify the development of severe hyperbilirubinemia. To prevent the development of severe hyperbilirubinemia, promote and support successful breast-feeding, perform a systemic assessment before discharge for the risk of severe hyperbilirubinemia, provide early and close follow-up program, and treat with phototherapy or exchange transfusion or other therapeutic modalities, if indicated, are recommended.