• Journal of the Ergonomics Society of Korea
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• v.20 no.3
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• pp.1-9
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• 2001

In the present study, the correlation between subjective assessment and EEG for essential odors were investigated quantitatively. EEG signals were measured from 19 electrodes according to the International 10-20 system (Fp1, Fp2, F3/4, F7/8, Fz, C3/4, Cz, P3/4, Pz, T3/4, T5/6, O1/2) from 8 healthy males subjects for four odor(Rose oil bulgarian, Lemon oil misitano, jasmin abs, Laverder oil france (KIMEX co. Ltd) conditions. The result of the subjective assessment shows the most pleasant odor for each subject. and the power spectrum of ${\alpha}/({\alpha}+{\beta})$ of EEG signals from the most pleasant odor was compared with those from the control condition, which has no odor at all. Power spectrum of ${\alpha}/({\alpha}+{\beta})$ of EEG from the most pleasant odor was increased significantly at T4, T6 compared to the control condition. This result implies that the parameter, power spectrum of ${\alpha}/({\alpha}+{\beta})$, could be an important index for signifying the levels of pleasantness for odors.

• Communications for Statistical Applications and Methods
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• v.4 no.1
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• pp.229-241
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• 1997

We consider discrimination curve and minimum dwell time for Poisson distribution and Poisson-power function distribution. Let the random variable X has Poisson distribution with mean .lambda.. For the hypothesis testing H$\_$0/:.lambda. = t vs. H$\_$1/:.lambda. = d (d$\_$0/ if X.leq.c. Since a critical value c can not be determined to satisfy both types of errors .alpha. and .beta., we considered discrimination curve that gives the maximum d such that it can be discriminated from t for a given .alpha. and .beta.. We also considered an algorithm to compute the minimum dwell time which is needed to discriminate at the given .alpha. and .beta. for the Poisson counts and proved its convergence property. For the Poisson-power function distribution, we reject H$\_$0/ if X.leq..'{c}.. Since a critical value .'{c}. can not be determined to satisfy both .alpha. and .beta., similar to the Poisson case we considered discrimination curve and computation algorithm to find the minimum dwell time for the Poisson-power function distribution. We prosent this algorithm and an example of computation. It is found that the minimum dwell time algorithm fails for the Poisson-power function distribution if the aiming error variance .sigma.$\^$2/$\_$2/ is too large relative to the variance .sigma.$\^$2/$\_$1/ of the Gaussian distribution of intensity. In other words, if .ell. is too small, we can not find the minimum dwell time for a given .alpha. and .beta..

• Journal of the Korean Mathematical Society
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• v.44 no.6
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• pp.1267-1279
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• 2007

For a ring endomorphism ${\alpha}$ and an ${\alpha}-derivation\;{\delta}$ of a ring R, we study relation between the set of annihilators in R and the set of annihilators in nearring $R[x;{\alpha},{\delta}]\;and\;R_0[[x;{\alpha}]]$. Also we extend results of Armendariz on the Baer and p.p. conditions in a polynomial ring to certain analogous annihilator conditions in a nearring of skew polynomials. These results are somewhat surprising since, in contrast to the skew polynomial ring and skew power series case, the nearring of skew polynomials and skew power series have substitution for its "multiplication" operation.

• Journal of Nutrition and Health
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• v.36 no.9
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• pp.918-923
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• 2003

L-theanine Is an amino acid in green tea and has been known to decrease serotonin and increase norepinephrine in rat brains, and also reported to produce mental relaxation, lower blood pressure and improve learning ability in human beings. But, few studies on these effects for human beings have been conducted so far. This study was conducted to evaluate the effect of L-theanine on the release of brain alpha waves known to be related with mental relaxation and concentration. Twenty healthy male volunteers aged 18 to 30 years without any Physical and Psychological diseases were recruited through written advertisement. Alpha power values of EEG as a surrogate marker of mental relaxation and concentration were measured in frontal and occipital regions for 40 minutes after administration of four placebo or test tablets and 20 minute resting period. The same procedure crossed over at 7-day intervals. We analyzed average alpha power values in frontal and occipital regions at 10 minute intervals. Repeated ANOVA revealed that there were significant differences of occipital alpha power values between placebo and test groups with high anxiety (p < 0.05). The mean values at 20,30,40,50 and 60 minute intervals were 0.23, 024, 0.28, 0.25 and 0.34 in placebo, respectively and 0.23, 0.29, 0.40, 0.34, and 0.45 in test, respectively. But there were no significant differences of frontal and occipital alpha power values between placebo and test groups with low anxiety (p > 0.05) . The results of this study suggest that L-theanine containing tablets promote the release of alpha waves related to mental relaxation and concentration in young adult males.

• Journal of the Korean Solar Energy Society
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• v.34 no.1
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• pp.72-80
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• 2014

This study proposed a wind power generation system utilizing outdoor air on the rooftop and indoor ventilation, which would increase according to the building height, as a way to help to save energy consumption in a building by using wind power energy of the new renewable energy sources. The study measured the distribution of air currents and power generation according to the usage factor of exhaust pipes in the kitchen and bathroom and identified the elements to consider when applying a wind power generation system to buildings in order to use outdoor air on the rooftop increasing according to the height and the indoor ventilation produced in the facility vertical shafts inside the buildings by installing a wind power generation system on the rooftop. (1) The study measured the ventilation velocity of the kitchen hood and bathroom ventilation fan by changing the zone areas by the households according to the usage factor of [${\alpha}$]=33~100%. As a result, the kitchen ventilation pipe generated the ventilation wind of 3.0m/s or more at the usage factor of [${\alpha}$] 66% or higher, and the bathroom ventilation pipe generated ventilation velocity lower than 3.0m/s, the blade velocity of the wind power generator, even after the usage factor rose to [${\alpha}$]=100%. (2) As the old bathroom ventilation pipe generated the ventilation velocity of 3.0m/s, the blade velocity of the wind power generator, even with the rising usage factor [${\alpha}$], the application of an outdoor air induction module increased the ventilation velocity by 2.9m/s at the usage factor of [${\alpha}$]=33%, 3.8m/s at the usage factor of [${\alpha}$]=66%, and 3.6m/s at the usage factor of [${\alpha}$]=100%. Thus the ventilation velocity of 3.0m/s, the blade velocity of the wind power generator, or higher was secured. (3) The findings prove that the applicability of a wind power generation system using outdoor air on the rooftop and indoor ventilation is excellent, which raises a need for various efforts to increase the possibility of its commercialization such as securing its structural stability according to momentary gusts on the rooftop and typhoons in summer and making the structure light to react to the wind directions of outdoor air on the rooftop according to the seasons.

• Journal of the Korean Applied Science and Technology
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• v.6 no.1
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• pp.51-57
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• 1989

A series of four sodium ${\alpha}-sulfo$ fatty vinyl ester oligomers including sodium ${\alpha}-sulfo$ lauric acid vinyl ester oligomer, sodium ${\alpha}-sulfo$ myristic acid vinyl ester oligomer, sodium ${\alpha}-sulfo$ palmitic acid vinyl ester oligomer and sodium ${\alpha}-sulfo$ stearic acid vinyl ester oligomer were examined for surface activities such as surface tension, foaming power, foam stability, emulsifying power, dispersion effect, solubilization of orange OT. The critical micelle concentration(CMC) was also evaluated. Consequently, these sodium ${\alpha}-sulfo$ fatty acid vinyl ester oligomers were shown to have a good cohesive power and dispersion effect.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.6
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• pp.15-20
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• 1998

The linewidth enhancement factor $\alpha$ and fiber dispersion of 1.55 ${\mu}{\textrm}{m}$ strained multi-quantum well laser diodes are measured using small signal power modulation transfer function in a dispersive fiber. The measured fiber dispersion values are between 16.766 and 16.786ps/nm/km and these are the expected values from standard single mode fiber. To measure the $\alpha$ parameter in the actual operational range of the laser diodes, the dependence of $\alpha$ on laser output power is measured. The $\alpha$ parameter increases linearly as the power of the laser diode increases. This result can explain the non-linear gain effect on the $\alpha$ parameter more accurately than any other measurements.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.1893-1898
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• 1998

We have redefined the $\alpha$ -parameter of the extended transmitters in the presence of self-phase modulation (SPM) induced chirp. The $\alpha$ -parameter is effectively lowered to about 1, when the SPM effect with the launching power of 12.5dBm (maximum launching power to avoid stimulated Brillouin scattering(SBS)) is included, compared to the $\alpha$ -parameter of the transmitter algone. The lowered $\alpha$ -parameter has improved the transmission performance significantly regardless the transmitter is operated with positive or negative chirp. The SPM-induced effective $\alpha$ -parameter can be used as a design parameter for the high speed (10 Gbps) transmission systems.

• Journal of Biomedical Engineering Research
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• v.29 no.5
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• pp.355-363
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• 2008

In order to extract only the alpha activity related signals from EEG recordings, we have applied Constrained Independent Component Analysis (cICA), a new extension of ICA in which some a priori knowledge of the alpha activity is utilized to extract only desired components. Its extraction (or filtering) performance has been compared to that of the conventional band-pass filtering via the scalp alpha power maps and cortical source maps of the alpha activity. Our results demonstrate that the alpha power maps and cortical source maps from the cICA-extracted alpha signals reveal more focalized alpha generating regions of the brain than those from the band-pass filtered alpha EEG signals. Furthermore they match more closely the activated regions of the brain mapped using fMRI, validating our results. We believe that the cICA-based filtering approach of EEG signals is a more effective means of extracting a specific brain activity reflected in EEG signals that will result in more accurate source localization or imaging maps.

• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.541-550
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• 2007

This paper presents characterizations of the power distribution with the parameter $\beta=1$ by the independence of the lower record values. We prove $X\;{\in}\;POW({\alpha},\;1)$ for ${\alpha}\;>\;0$, if and only if $\frac{X_{L(n)}}{X_{L(m)}}$ and $X_{L(m)}$ for $1\;{\leq}\;m\;<\;n$ are independent. And we prove that $X\;{\in}\;POW({\alpha},\;1)$ for ${\alpha}\;>\;0$, if and only if $\frac{X_{L(m)}-X_{L(m+1)}}{X_{L(m)}}$ and $X_{L(m)$ for $m\;{\geq}\;1$ are independent or $\frac{X_{L(m)}-X_{L(m+1)}}{X_{L(m+1)}}$ and $X_{L(m)}$ for $m\;{\geq}\;1$ are independent.