• Annals of Clinical Neurophysiology
• /
• v.3 no.1
• /
• pp.26-30
• /
• 2001

Purpose : Eyeball movement is one of the main artifacts in EEG. A new approach to the removal of these artifacts is presented using independent component analysis(ICA). This technique is a signal-processing algorithm to separate independent sources from unknown mixed signals. This study was performed to show that ICA is a useful method for the separation of EEG components with little data deformity. Methods : 12 sets of 10 sec digital EEG data including eye opening and closure were obtained using international 10~20 system scalp electrodes. ICA with 18 tracings of double banana bipolar montage was performed. Among obtained 18 independent components, two components, which were thought to be eyeball movements were removed. Other 16 components were reconstructed into original bipolar montage. Power spectral analysis of EEGs before and after ICA was done and compared statistically. Total 12 pairs of data were compared by visual inspection and relative power comparison. Results : Waveforms of each pair looked alike by visual inspection. Means of relative power before and after ICA were 29.16% vs. 28.27%, 12.12% vs. 12.41%, 10.55% vs. 10.52%, and 19.33% vs. 18. 33% for alpha, beta, theta, and delta, respectively. These values were statistically same before and after ICA. Conclusions : We found little data deformity after ICA and it was possible to isolate eyeball movements in EEG recordings. Many other components of EEG could be selectively separated using ICA.

• Journal of Drive and Control
• /
• v.16 no.4
• /
• pp.65-73
• /
• 2019

In this study, flow analysis and fluid-solid interaction analysis were conducted on a hollow fiber membrane module used for analysis of dehumidification characteristics. To ensure the reliability of the flow analysis results, the dehumidification experiment was performed under the temperature of 30℃ and relative humidity of 30% RH. The results of the dehumidification experiments were compared with the flow analysis results. The results of dehumidification experiments and flow analysis had a difference of approximately 5%. A 1-Way fluid-solid interaction analysis with various materials was conducted. From the results, it was found that the baffle with the largest shape deformation (polyethylene material) was subjected to 2-way fluid-solid interaction. The analysis of fluid flow and dehumidification characteristics were analyzed according to the shape deformation of the baffle.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.498-500
• /
• 2009

When we urgently need to develop and supply an alternative energy, wind power is growing with much interest because it has relative low cost for generating power and small area for wind turbine. To estimate the wind power resource, it is necessary to make an observation first. Although the large wind farm and resources are near coast and mountain area, the wind energy in urban area has the strong thing of direct access to power generator. In this study, we estimate the probability of wind energy in urban mountain area using A2C (Atmospheric to CFD) model, which is used for horizontally urban scale phenomena. In the steady state results, the site C is most suitable for wind power in the point of the only wind speed. But, estimating the TKE and vertical wind shear, the site B is showing the better results than the site C.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.7
• /
• pp.543-553
• /
• 2020

The purpose of this study is to analyze the effects of subjective class consciousness on life satisfaction. This research aimed to not only analyze the relative explanatory power, but also the influence of satisfaction of life within the socioeconomic status where the elderly consider themselves to be an integral part. The elderly's satisfaction in life was analyzed in comparison with demographic characteristics such as gender and age. The correlations of objective socioeconomic characteristics such as income level and education level were also observed. For this purpose, the Korea Labor Panel 17th data (2014) was used to conduct a one-way batch distribution analysis and a hierarchical regression analysis. It was seen that there was a correlation in the Korean elderly in terms of class consciousness and life satisfaction. The elderly with a lower subjective class consciousness showed lower life satisfaction. The relative influences were stronger than the demographic and socioeconomic characteristics of the elderly, and the explanatory power was much higher than the objective income levels. These results show that the subjective perception of their socioeconomic status has a significant influence on the level of life satisfaction of the Korean elderly, independent of the objective income level.

• Journal of Powder Materials
• /
• v.28 no.5
• /
• pp.410-416
• /
• 2021

Ti-6Al-4V alloy has a wide range of applications, ranging from turbine blades that require smooth surfaces for aerodynamic purposes to biomedical implants, where a certain surface roughness promotes biomedical compatibility. Therefore, it would be advantageous if the high volumetric density is maintained while controlling the surface roughness during the LPBF of Ti-6Al-4V. In this study, the volumetric energy density is varied by independently changing the laser power and scan speed to document the changes in the relative sample density and surface roughness. The results where the energy density is similar but the process parameters are different are compared. For comparable energy density but higher laser power and scan speed, the relative density remained similar at approximately 99%. However, the surface roughness varies, and the maximum increase rate is approximately 172%. To investigate the cause of the increased surface roughness, a nonlinear finite element heat transfer analysis is performed to compare the maximum temperature, cooling rate, and lifetime of the melt pool with different process parameters.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.2
• /
• pp.168-175
• /
• 2001

Reduction of structure-borne noise of the compartment in a car is an important task in automotive engineering. Transfer path analysis using vibroacoustic reciprocity technique or multiple path decomposition method has generally been used for structure-borne noise path analysis. These methods are useful in solving particular problem but do net quantify the effectiveness of vibration isolation of each isolator of a vehicle. To quantify the effectiveness of vibration isolation, the vibrational power flow has been used for a simple isolation system or a laboratory based isolation system. It is often difficult to apply the vibrational power flow technique to the complex isolation system like a car. In this paper, a simple equation is derived for calculation of the vibrational power flow of an isolation system with multiple isolators such as a car. It is successfully applied to not only quantifying the relative contributions of eighteen isolators but also reducing structure-borne noise of a passenger car. According to the results, the main contributor of eighteen isolators is the rear roll mount of an engine. The reduced structure-borne noise level is about 5dBA.

• Nuclear Engineering and Technology
• /
• v.54 no.5
• /
• pp.1813-1824
• /
• 2022

This paper shows the verification work of SARAX code system in the reactor core transient calculation based on the simplified EBR-II Benchmark. The SARAX code system is an analysis package developed by Xi'an Jiaotong University and aims at the advanced reactor R&D. In this work, a neutron-photon coupled power calculation model and a spatial-dependent reactivity feedback model were introduced. To verify the models used in SARAX, the EBR-II SHRT-45R test was simplified to an ULOF transient with an input flowrate change curve by fitting from reference. With the neutron-photon coupled power calculation model, SARAX gave close results in both power fraction and peak power prediction to the reference results. The location of the hottest assembly from SARAX and reference are the same and the relative power deviation of the hottest assembly is 2.6%. As for transient analysis, compared with experimental results and other calculated results, SARAX presents coincident results both in trend and absolute value. The minimum value of core net reactivity during the transient agreed well with the reported results, which ranged from -0.3$ to -0.35$. The results verify the models in SARAX, which are correct and able to simulate the in-core transient with reliable accuracy.

• Nuclear Engineering and Technology
• /
• v.31 no.4
• /
• pp.375-384
• /
• 1999

The credibility of CHECWORKS FAC model analysis was evaluated for plant application in a model plant chosen for demonstration. The operation condition at each pipe component was defined before the wear rate analysis by plant data base, water chemistry analysis, and network flow analysis. The predicted wear was compared with the measured wear for 57 sample components selected from 43 susceptible line groups analysed. The inspected 57 locations represent components of highest predicted wear in each line group. Both absolute value and relative ranking comparisons indicated reasonable correlations between the predicted and the measured values. Four components showed much higher measured wear rates than the predicted ones in the feed water train from main feed water pump discharge to steam generator, probably due to high hydrazine concentration operation the effect of which had not been incorporated into the CHECWORKS model. The measured wear was higher than the predicted one consistently for components with least susceptibility to FAC. It is believed that the conservatism maintained during UT data analysis dominated the measurement accuracy. A great deal of enhancement is anticipated over the current plant pipe management program when a comprehensive plant pipe management program is implemented based on the model analysis.

• Journal of Korean Society for Geospatial Information Science
• /
• v.18 no.2
• /
• pp.107-112
• /
• 2010

Wind power generation is the natural source energy without pollution, and the highest economic efficiency among renewable energies. Amid the recent development of small wind power generation, wind power generation facilities can be installed in the super high-rise buildings or complexes. It is necessary to conduct analyses on appropriate locations in a bid to promote efficient power generation in those locations. In this study, relative weight of the elements required for the wind power generation were estimated by using the Analytic Hierarchy Process in Busan City, and the characteristics of wind velocity and wind direction in Busan City were expressed. As a result, 'Dadae 1-dong, Cheolma-myeon, Noksan-dong' was selected as the candidate region inside Gangseo-gu, Gijang-gun, Saha-gu by using the geo-spatial information system.

• Korean Journal of Oriental Medicine
• /
• v.13 no.1 s.19
• /
• pp.85-92
• /
• 2007

To evaluate the suitability and effectiveness of the questionnaire concerning personal properties on 'pattern of speech and activity' according to the Sasang constitution that were used in Iksan Wonkwang Oriental Medicine, we analyzed the data of 1,335 patients obtained through the electronic chart in the aspect of 'relative discrimination ability' to Sasang constitutions and 'response ratio' using statistical Package SPSS. In categories of 'speech pattern', No.2 (speak mildly and softly) was effectively discriminating Soeum type. No.4 (talkative) and No.7 (speak fast) were effective factors for the discrimination of Soyang type, though No.4 (talkative) was needed to be improved in response ratio. The category of 'activity pattern' has shown high response ratio but low discriminating power. However, No.2 (keep staying home but avoid going out) in this category was effectively discriminating Soeum type. The discriminating power of 'pattern of speech and activity' for the age group less than 20 years old was too low, so it is necessary to develop the questionnaire for the elementary to high school students as well as for the preschoolers.