• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.301-302
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• 2019

ITER CS, VS, CC AC/DC Converter는 4상한 동작을 하며, PCS(Plasma Control System)에서 명령하는 출력 전압 제어를 컨버터 교류 입력 전압 변동을 보상하는 Feed-forward 방식을 사용한다. Feed-forward 제어를 위하여 교류 입력 전압에 대한 실시간 정밀 측정이 가능한 RMS 계산이 필요하다. 본 논문은 RMS 연산에 대한 개선된 방법을 제안하면서 시뮬레이션과 실험을 통해 해당 알고리즘을 검증하였고 이에 대한 내용을 논의하고자 한다.

• The Journal of Korean Physical Therapy
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• v.21 no.3
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• pp.87-93
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• 2009

Purpose: TThis study examined the effect of repetitive magnetic stimulation (RMS) on the viability and proliferative response of human adipose tissue-derived stromal cells (hATSCs) in vitro. Methods: The hATSCs were cultured primarily from human adipose tissue harvested by liposuction and incubated in a $37^{\circ}C$ plastic chamber. The cells were exposed to a repetitive magnetic field using a customized magnetic stimulator (Biocon-5000, Mcube Technology). The RMS parameters were set as follows: repetition rate=10Hz, 25Hz (stimulus intensity 100%= 0.1 Tesla, at 4cm from the coil), stimulated time= 1, 5, and 20 minutes. Twenty four hours after one application of RMS, the hATSCs were compared with the sham stimulation, which were kept under the same conditions without the application of RMS. The cells were observed by optical microscopy to determine the morphology and assessed by trypan blue staining for cell proliferation. The apoptosis and viability of the hATSCs were also analyzed by fluorescence-activated cell sorting (FACS) analysis of Annexin V and MTT assay. Results: After RMS, the morphology of the hATSCs was not changed and the apoptosis of hATSCs were not increased compared to the sham stimulation. The viability of the cells was similar to the cells given the sham stimulation. Interestingly, the level of hATSC proliferation was significantly higher in all RMS groups. Conclusion: The application of RMS may not cause a change in morphology and viability of hATSCs but can increase the level of cell proliferation in vitro. RMS might be useful as an adjuvant tool in combination with stem cell therapy without adverse effects.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.288-289
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• 2009

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.3
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• pp.239-246
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• 2006

This paper suggests a new modulation strategy for step pulse type multi-level inverter. The proposed strategy is simple to determine the switching angles without regard to increase of levels. Designed to extract the equivalent RMS value compared to ideal sine wave from inverter, it can be applied effectively to high level step pulse inverter. Also this paper proposed modulation strategy for modified H-bridge 13 level inverter which has different cell source voltages with simulation and experiment. The modulation characteristics from simulation and experiment, agreed very well with tracing sine wave about modified structure of cascaded H-bridge multi-level inverter.

• Journal of the Korean Vacuum Society
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• v.13 no.1
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• pp.34-38
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• 2004

Hot embossing master is indispensable for the fabrication of polymeric optical waveguides using hot embossing technology. Sidewall roughness of silicon master is directly related to optical loss of optical waveguides In this paper, a silicon master was fabricated by using a deep-RIE process. Additionally, thermal oxidation followed by oxide removal was carried out to minimize etched Si sidewall roughness. Thermal oxidation and oxide removal were performed with $H_2O_2$ atmosphere at $1050^{\circ}C$ and $NH_4$F:HF=6:l BOE, respectively, for the oxide thickness of 400$\AA$, 1000$\AA$, 3000$\AA$, 4500$\AA$, 5600$\AA$ and 6200$\AA$. The sidewall roughness was characterized by SEM and SPM-AFH measurements. We found that the roughness was improved from 12nm (RMS) to 6nm (RMS) for the scalloped sidewall and from 162nm (RMS) to 39nm (RMS) for the vertical striation sidewall, respectively.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.6
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• pp.90-96
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• 1998

The ductile cast iron is austempered at 300, 350 and 40$0^{\circ}C$ temperature in order to investigate the basic factors for monitoring drill wear in automatic production process, and cutting force and AE RMS signals are measured with changing cutting condition for ADI(Austempered Ductile Cast Iron) with different mechanical properties. The signals of cutting force were influenced by cutting speed and feedrate greatly. On the other hand AE RMS signals are influenced by cutting speed where as it is not related with feedrate. As the depth of drilling increases, cutting force shows a slow increase and the value of AE RMS increases until the range of h/d=4. But over the range it increases greatly due to an amount of chip discharge and friction with inner wall of drilling hole, etc. As the drill diameter increases at a constant depth of drilling. Cutting force increases linearly, but the level of AE RMS does not increases linearly due to circumferential velocity and great influence of h/d.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.69-74
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• 2013

In this paper, we propose the pattern classification algorithm of recognizing wrist movements based on electromyogram(EMG) to raise the recognition rate. We consider 30 characteristics of EMG signals wirh the root mean square(RMS) and the difference absolute standard deviation value(DASDV) for the extraction of precise features from EMG signals. To get the groups of each wrist movement, we estimated 2-dimension features. On this basis, we divide each group into two parts with mean to compare and promote the recognition rate of pattern classification effectively. For the motion classification based on EMG, the k-nearest neighbor(k-NN) is used. In this paper, the recognition rate is 92.59% and 0.84% higher than the study before.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.10
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• pp.788-793
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• 2017

This paper presents the verification of accuracies of theoretical models for calculating the microwave reflections from rough sea surfaces. First of all, the Pierson-Moskowitz ocean spectrum was used to generate the rough sea surfaces. Then the relationship between the significant wave heights, root-mean-square(RMS) heights and wind speed was derived by estimating the significant wave heights and RMS heights of the generated sea surfaces according to various wind speeds, and compared the derived relationship with other measurement data sets. The reflection coefficients of the sea surfaces were calculated by using a numerical method(the moment method). Then, the numerical results were compared with Ament model, PO(Physical Optics) model, GO(Geometrical Optics) model and B-M(Brown-Miller) model for various roughness conditions(wind speed) and incidence angles. It was found that the Ament model is not accurate except for a very low roughness conditions($kh_{rms}$<0.4, k is wavenumber and $h_{rms}$ is RMS height). It was also found that at incidence angles lower than $70^{\circ}$, the PO and the GO models agree well with the numerical results, while the B-M model agrees well with the numerical analysis results at incidence angles higher than $80^{\circ}$ for very rough sea surfaces with $kh_{rms}$>10.

• Journal of the Korean Ceramic Society
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• v.41 no.7
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• pp.493-496
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• 2004

The chemical etching of sapphire substrates was peformed to produce smooth surfaces on an atomic scale. The sapphire sur-face etched by using a $H_2$S $O_4$ solution showed a pit-free morphology and was yen smooth as much as $\sigma$$_{rms}$=0.13 nm, that etched by using a mixture of $H_2$S $O_4$ and $H_3$P $O_4$ contained large pits with $\sigma$$_{rms}$=0.34 nm. The $\sigma$$_{rms}$’s and the number of the pits increased with increasing etching temperature. The sapphire etched by using $H_2$S $O_4$ at 32$0^{\circ}C$ had the best surface. These results provide important information on the effects of etching treatment on the structural properties of sapphire for the growth of high-quality epilayers.ayers.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.579-580
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• 2009