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186 results on '"Cho, Kyung Rae"'

32. Additional file 1 of Intracerebroventricular injection of human umbilical cord blood mesenchymal stem cells in patients with Alzheimer’s disease dementia: a phase I clinical trial

Author

Kim, Hee Jin, Cho, Kyung Rae, Jang, Hyemin, Lee, Na Kyung, Jung, Young Hee, Kim, Jun Pyo, Lee, Jung Il, Chang, Jong Wook, Park, Seongbeom, Kim, Sung Tae, Moon, Seung Whan, Seo, Sang Won, Choi, Soo Jin, and Na, Duk L.

Abstract

Additional file 1. The optimal injection dose of hUCB-MSCs.

Published
2021
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34. Pure-integration-based flux acquisition with drift and residual error compensation at a low stator frequency

Author

Cho, Kyung-Rae and Seok, Jul-Ki

Subjects
Business, Computers, Electronics, Electronics and electrical industries
Abstract

We have developed a pure-integration-based flux acquisition method for ac adjustable-speed drives. Based on the current-measurement-error analysis, a simple resonant-type observer is utilized to eliminate the drift or dc offset that originated in the current acquisition process. All the processes in correcting the problem do not rely on motor parameters and do not interfere with other higher frequency contents such as inverter non-linearity and motor cogging effects. The proposed technique further contains a residual error compensator to completely correct the initial value error and to eliminate miscellaneous dc offset errors of the integrator. The acquisition accuracy of the flux is significantly improved through pure integration by restraining the error of the flux magnitude and phase angle at a low stator frequency. Since the proposed scheme is based on a two-phase current measurement system, it is suitable for retrofitting ac drives, where two current sensors are commonly used. Index Terms--Current measurement error, pure-integration-based flux acquisition, residual error compensator, resonant-type observer (RTO).

Published
2009

35. Induction motor rotor temperature estimation based on a high-frequency model of a rotor bar

Author

Cho, Kyung-Rae and Seok, Jul-Ki

Subjects
Induction electric motors -- Analysis, Business, Computers, Electronics, Electronics and electrical industries
Abstract

This paper analyzes a high-frequency (HF) voltage-injection-based rotor winding temperature estimation method for current-regulated squirrel-cage induction motors (IMs). We develop a theoretical I-IF model of the rotor bar and then first provide an analysis of relevant HF model-based estimation aspects, such as the dependence of the rotor leakage inductance on the temperature and the relationship between the rotor resistance and rotor leakage inductance. We also include an analysis of magnetic saturation to improve the estimation accuracy, as well as an analysis of the phase delay effect resulting from the drive that significantly affects the HF signal precision. Then, a specialized offline commissioning scheme is proposed to compensate for the effect of the phase delay and magnetic saturation. The estimation technique and sensitivity analysis are verified by means of experiments performed on an inverter-fed 1.5-kW IM. Index Terms--High-frequency (HF) model of rotor bar, high-frequency (HF) voltage injection, inverter-fed induction motor (IM), phase delay resulting from the drive, rotor winding temperature estimation.

Published
2009

38. Immune Checkpoint Inhibitors for Non-Small-Cell Lung Cancer with Brain Metastasis : The Role of Gamma Knife Radiosurgery

Author

Lee, Min Ho, primary, Cho, Kyung-Rae, additional, Choi, Jung Won, additional, Kong, Doo-Sik, additional, Seol, Ho Jun, additional, Nam, Do-Hyun, additional, Jung, Hyun Ae, additional, Sun, Jong-Mu, additional, Lee, Se-Hoon, additional, Ahn, Jin Seok, additional, Ahn, Myung-Ju, additional, Park, Keunchil, additional, and Lee, Jung-Il, additional

Published
2021
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39. Correction on current measurement errors for accurate flux estimation of AC drives at low stator frequency

Author

Cho, Kyung-Rae and Seok, Jul-Ki

Subjects
Electric currents -- Measurement, Alternating current electric motors -- Design and construction, Parameter estimation -- Technology application, Industrial electronics -- Research, Technology application, Business, Computers, Electronics, Electronics and electrical industries
Abstract

This paper presents an online-correction method for current measurement errors for a pure-integration-based flux estimation down to a stator frequency of 1 Hz. A measurement-disturbance-observer (MDO)-based approach is taken as one possible solution for eliminating the dc offset and the additional negative-sequence component due to unbalanced current measurement gains in the synchronous coordinate. From the motor parameter sensitivity analysis, an MDO gain selection method is proposed to remove the estimation error resulting from a parameter mismatch. At the same time, the positive-sequence component estimation is performed by creating an error signal between a motor model reference and an estimated q-axis rotor flux established by a permanent magnet in the synchronous coordinate. The compensator utilizes a PI controller that controls the error signal to zero. Experimental results confirm that the proposed scheme has great potential for applications to acquire the accurate motor flux at a low stator frequency. Index Terms--DC offset, measurement disturbance observer (MDO), negative-sequence component due to unbalanced current measurement gains, online-correction method of current measurement errors, positive-sequence component estimation, pure-integration-based flux estimation.

Published
2008

40. Inverter nonlinearity compensation in the presence of current measurement errors and switching device parameter uncertainties

Author

Choi, Chan-Hee, Cho, Kyung-Rae, and Seok, Jul-Ki

Subjects
Electric power systems -- Design and construction, Nonlinear theories -- Usage, Vector analysis, Business, Electronics, Electronics and electrical industries
Abstract

This paper proposes a compensation strategy for the unwanted disturbance voltage due to inverter nonlinearity. We employ an emerging learning technique called support vector regression (SVR). SVR constructs a motor dynamic voltage model by a linear combination of the current samples in real time. The model exhibits fast observer dynamics and robustness to observation noise. Then the disturbance voltage is estimated by subtracting the constructed voltage model from the current controller output. The proposed method compensates for all of the inverter nonlinearity factors at the same time. All the processes in estimating distortions are independent of the dead time and power device parameters. From the analysis of the effect on current measurement errors, we confirmed that the sampling error had little negative impact on the proposed estimation method. Experiments demonstrate the superiority of the proposed method in suppressing voltage distortions caused by inverter nonlinearity. Index Terms--Current :measurement errors, disturbance voltage resulting from inverter nonlinearity, power device parameters, support vector regression (SVR).

Published
2007

41. NIMG-20. MULTI-HABITAT RADIOMICS UNRAVELS DISTINCT PHENOTYPIC SUBTYPES OF GLIOBLASTOMA WITH CLINICAL AND GENOMIC SIGNIFICANCE

Author

Won Choi, Seung, primary, Cho, Hwan-ho, additional, Koo, Harim, additional, Cho, Kyung rae, additional, Nenning, Karl-Heinz, additional, Langs, Georg, additional, Furtner, Julia, additional, Baumann, Bernhard, additional, Woehrer, Adelheid, additional, Cho, Hee Jin, additional, Kong, Doo-Sik, additional, Seol, Ho Jun, additional, Lee, Jung-il, additional, Nam, Do-Hyun, additional, and Park, Hyunjin, additional

Published
2020
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45. Multi-Habitat Radiomics Unravels Distinct Phenotypic Subtypes of Glioblastoma with Clinical and Genomic Significance

Author

Choi, Seung Won, primary, Cho, Hwan-Ho, additional, Koo, Harim, additional, Cho, Kyung Rae, additional, Nenning, Karl-Heinz, additional, Langs, Georg, additional, Furtner, Julia, additional, Baumann, Bernhard, additional, Woehrer, Adelheid, additional, Cho, Hee Jin, additional, Sa, Jason K., additional, Kong, Doo-Sik, additional, Seol, Ho Jun, additional, Lee, Jung-Il, additional, Nam, Do-Hyun, additional, and Park, Hyunjin, additional

Published
2020
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50. The Effect of Globus Pallidus Interna Deep Brain Stimulation on a Dystonia Patient with the GNAL Mutation Compared to Patients with DYT1 and DYT6

Author

Ahn, Jong Hyeon, primary, Kim, Ah Reum, additional, Kim, Nayoung K. D., additional, Park, Woong-Yang, additional, Kim, Ji Sun, additional, Kim, Minkyeong, additional, Park, Jongkyu, additional, Lee, Jung-Il, additional, Cho, Jin Whan, additional, Cho, Kyung Rae, additional, and Youn, Jinyoung, additional

Published
2019
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