• Bulletin of the Korean Mathematical Society
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• v.52 no.2
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• pp.581-591
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• 2015

Let $\mathcal{A}$ be a factor von Neumann algebra with dimension greater than 1. We prove that if a linear map ${\delta}:\mathcal{A}{\rightarrow}\mathcal{A}$ satisfies $${\delta}([[a,b],c])=[[{\delta}(a),b],c]+[[a,{\delta}(b),c]+[[a,b],{\delta}(c)]$$ for any $a,b,c{\in}\mathcal{A}$ with ab = 0 (resp. ab = P, where P is a fixed nontrivial projection of $\mathcal{A}$), then there exist an operator $T{\in}\mathcal{A}$ and a linear map $f:\mathcal{A}{\rightarrow}\mathbb{C}I$ vanishing at every second commutator [[a, b], c] with ab = 0 (resp. ab = P) such that ${\delta}(a)=aT-Ta+f(a)$ for any $a{\in}\mathcal{A}$.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.163-167
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• 2000

This paper presents the digital control of single-phase power factor correction(PFC) converter which has the variable gain according to the condition of inner control loop error. Generally the gain of inner current control loop in single-stage PFC converter has a constant magnitude. This has a bad influence on the power factor because current loop doesn't operate smoothly in the condition that input voltage is low In particular a digital controller has more time delay than an analog controller and degrades This drops the phase margin of the total digital PFC system,. It causes the problem that the gain of current control loop isn't increased enough. In addition the oscillation happens in the peak value of the input voltage open loop PFC system gain changes according to ac input voltage. These aspects make the design of the digital PFC controller difficult The digital PFC controller presented in this paper has a variable gain of current control loop according to input voltage. The 1kW converter was used to verify the efficiency of the digital PFC controller.

• Communications for Statistical Applications and Methods
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• v.11 no.2
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• pp.247-254
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• 2004

Tusher, Tibshirani and Chu (2001) suggested SAM (Significance Analysis of Microarrays) to compare two groups under different conditions for each gene, using microarray data. They used two sample t-statistic adding fudge factor in the denominator to prevent the value of statistic from being inflated by large sample variance, which might result in significant difference despite of a small value in the numerator. This paper aims at finding robust fudge factor and replacing it in two-sample t-statistic used in SAM, which we call Modified SAM (MSAM). Using the simulated data and data used in Dudoit et al.(2002), it is shown that MSAM find significant genes better and has less error rate than SAM.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.129-138
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• 2010

For the fractional factorial designs, the resolution-IV designs can be used when we want to estimate the main effects and to investigate the structure of the non-negligible two-factor interaction effects, when the three-factor and higher order interaction effects are all negligible. However we need to add the additional treatment combination in order to identify the influential interactions for the resolution-IV fracrtional factorial designs. In this paper we investigate the statistical structure for 3-level resolution-IV designs constructed by fold-over scheme and introduce a method for analyzing the influential two-factor interactions.

• Journal of applied mathematics & informatics
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• v.28 no.3_4
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• pp.687-696
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• 2010

In this paper, an algorithm for computing the sparse approximate inverse factor of matrix $A^{T}\;A$, where A is an $m\;{\times}\;n$ matrix with $m\;{\geq}\;n$ and rank(A) = n, is proposed. The computation of the inverse factor are done without computing the matrix $A^{T}\;A$. The computed sparse approximate inverse factor is applied as a preconditioner for solving normal equations in conjunction with the CGNR algorithm. Some numerical experiments on test matrices are presented to show the efficiency of the method. A comparison with some available methods is also included.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.264-269
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• 1998

A proposed soft-switching buck-boost PWM converter has a lot of advantages, Viz., electric isolation, a high power factor, low switching losses, low EMI noise, reduction of the voltage and current stresses, etc. In a new PFC converter, the switching device is replaced by the loss-less snubber circuit to achieve the zero voltage switching (ZVS) at the maximum current. However, the charging current of the capacitor in the loss-less snubber circuit distorts the input current waveforms. To improve the input current waveform, a new duty factor control method is proposed in this paper.

• Journal of the Korean Statistical Society
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• v.26 no.2
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• pp.261-276
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• 1997

In the context of binary response regression, the problem of constructing Bayesian goodness-of-link test for testing logit link versus probit link is considered. Based upon the well known facts that cdf of logistic variate .approx. cdf of $t_{8}$/.634 and, as .nu. .to. .infty., cdf of $t_{\nu}$ approximates to that of N(0,1), Bayes factor is derived as a test criterion. A synthesis of the Gibbs sampling and a marginal likelihood estimation scheme is also proposed to compute the Bayes factor. Performance of the test is investigated via Monte Carlo study. The new test is also illustrated with an empirical data example.e.

• Environmental Analysis Health and Toxicology
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• v.12 no.3_4
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• pp.75-84
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• 1997

Chromatographic retention behavior and separation of various phenol derivatives on a Partisil 10 ODS 3 column-with mobile phase containing $\alpha$-cyclodextrin-were systematically studied. The decrease in k' values caused by the addition of cyclodextrins in the mobile phase was based on the formation of an inclusion complex, resulting in weakening of the hydrophobic interaction between solutes and the stationary phase. The content of the organic solvent in the mobile phase also influenced k' values of the solutes, and k' values increased with a decrease of the content of organic solvent in the mobile phase. A simple equation has been derived that reveals the hyperbolic dependence of the capacity factor on the total concentration of cyclodextrin. A plot of the reciprocal of the capacity factor against (CD)$_T$ gives a straight line and the dissociation constant, K$_D$, of the inclusion complex can be calculated from the slope. The capacity factor decreased with increasing temperature. The enthalpy was calculated from the slope of van't Hoff plots. Under optimum conditions, some mixtures of phenol derivatives were able to separated successfully.

• Archives of Pharmacal Research
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• v.22 no.4
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• pp.348-353
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• 1999

Possible antiinflammatory effect of eudesmin were examined by assessing the effects on tumor necrosis factor (TNF)-$\alpha$ production and lymphocyte proliferation as well as cytotoxicity against murine and human macrophages. the compound significantly inhibited TNF-$\alpha$, production by lipopolysaccaride (LPS)-stimulated murine macrophage RAW264.7 without displaying cytotoxicity suggesting that eudesmin may inhibit TNF-$\alpha$ production without any interference of normal cell function. It also significantly attenuated T cell proliferation stimulated by concanavalin A (Con A) in a dose-dependent manner.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.228-232
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• 2002

In this paper, In order to solve the problem is proposed using a new type of electronic ballast that the traditional magnetic ballasts operated at 50-60Hz have been suffered from noticeable flicker, high loss, large crest factor and heavy weight which is composed of rectifier, active power corrector, series resonant half bridge inverter, micro-controller and piezoelectric transformer for driving for driving T5 fluorescent lamp were manufactured. The proposed electronic ballast operated at high frequency (about 75kHz) shows a input power factor of more than 0.995, total harmonic distortion of less than $12\%$ and lamp current crest factor of less than 1.5, respectively. Output power and efficiency showed 28w and $85\%$, respectively. Accordingly, it is considered that the ballast using piezoelectric transformer can replace the typical electronic ballast.