• 한국전산유체공학회:학술대회논문집
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• 2009.11a
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• pp.44-48
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• 2009

In this study, a vortex visualization method based on the vorticity magnitude is developed. One of the simplest models for a vortex is a vortex filament with the maximum vorticity on its center. The proposed method is based on the observation of this ideal distribution of vorticity magnitude. Laplacian and Hessian matrix of vorticity magnitude are tested for detecting the local maximum of vorticity magnitude. These ideas were applied to wake flow past a sphere. It was found that the Laplacian method is not able to distinguish vortices from the underlying shear layer clearly, while the Hessian matrix method does not suffer from this problem.

• Communications for Statistical Applications and Methods
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• v.5 no.2
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• pp.539-557
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• 1998

This article is concerned with the problem of estimating the mean of a one-parameter exponential family through sequential sampling in three stages under quadratic error loss. This more general framework differs from those considered by Hall (1981) and others. The differences are : (i) the estimator and the final stage sample size are dependent; and (ii) second order approximation of a continuously differentiable function of the final stage sample size permits evaluation of the asymptotic regret through higher order moments. In particular, the asymptotic regret can be expressed as a function of both the skewness $\rho$ and the kurtosis $\beta$ of the underlying distribution. The conditions on $\rho$ and $\beta$ for which negative regret is expected are discussed. Further results concerning the stopping variable N are also presented. We also supplement our theoretical findings wish simulation results to provide a feel for the triple sampling procedure presented in this study.

• Journal of the Korean Statistical Society
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• v.36 no.2
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• pp.237-256
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• 2007

This paper studies the problem of option pricing in an incomplete market. The market incompleteness comes from the discontinuity of the underlying asset price process which is, in particular, assumed to be a compound Poisson process. To find a reasonable price for a European contingent claim, we first find the unique minimal martingale measure and get a price by taking an expectation of the payoff under this measure. To get a closed-form price, we use an asymptotic expansion. In case where the minimal martingale measure is a signed measure, we use a sequence of martingale measures (probability measures) that converges to the equivalent martingale measure in the limit to compute the price. Again, we get a closed form of asymptotic option price. It is the Black-Scholes price and a correction term, when the distribution of the return process has nonzero skewness up to the first order.

• BMB Reports
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• v.43 no.2
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• pp.69-78
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• 2010

Asymmetric cell division is a fundamental mechanism for the generation of body axes and cell diversity during early embryogenesis in many organisms. During intrinsically asymmetric divisions, an axis of polarity is established within the cell and the division plane is oriented to ensure the differential segregation of developmental determinants to the daughter cells. Studies in the nematode Caenorhabditis elegans have contributed greatly to our understanding of the regulatory mechanisms underlying cell polarity and asymmetric division. However, much remains to be elucidated about the molecular machinery controlling the spatiotemporal distribution of key components. In this review we discuss recent findings that reveal intricate interactions between translational control and targeted proteolysis. These two mechanisms of regulation serve to carefully modulate protein levels and reinforce asymmetries, or to eliminate proteins from certain cells.

• The Korean Journal of Applied Statistics
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• v.24 no.6
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• pp.1021-1031
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• 2011

Equity linked securities are indirect investments where the return of investment depends on the performance of the underlying equities. In this paper, we review the profit structure of typical equity linked securities through a profit diagram and investigate which characteristics of time series at the investment affect the early repayment of the stepdown ELS based on KOSPI 200 and HSI. We also compare VaRs using the empirical distribution function for risk management.

• Communications for Statistical Applications and Methods
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• v.21 no.3
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• pp.261-274
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• 2014

In this paper we develop Bayes and empirical Bayes estimators of the finite population mean with the assumption of posterior linearity rather than normality of the superpopulation under the balanced loss function. We compare the performance of the optimal Bayes estimator with ones of the classical sample mean and the usual Bayes estimator under the squared error loss with respect to the posterior expected losses, risks and Bayes risks when the underlying distribution is normal as well as when they are binomial and Poisson.

• Journal of Chest Surgery
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• v.28 no.11
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• pp.1019-1024
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• 1995

Clinical analysis were performed on 68 cases of subcutaneous emphysema, those were visited at the emergency center of Chosun university hospital during the period form 1992 to 1994. The following result was obtained. 1 The incidence of subcutaneous emphysema was 0.16%, and male was dominant [M:F=6.9:1 .2 The age distribution of subcutaneous emphysema was from 4 to 77 years old and mean age was 49.6$\pm$17.8 years[$\pm$SD 3 The most presenting symptoms were chest pain[49% , and the proceeding cause was traffic accident[38% . 3 The most associated disease was a ipsilateral pneumothorax[59% . 4 Conservative management is an indication in the majority of cases of subcutaneous emphysema because it is usually a self-limited condition and spontaneous remission usually occurs. We conclude that initial effort must be made to detect the underlying cause of the subcutaneous emphysema in order that appropriate management may be undertaken.

• Korean Management Science Review
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• v.11 no.2
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• pp.133-146
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• 1994

This study compares the performance of neural networks and ordinary least squares regression with quality-control processes. We examine the applicability of neural networks because they do not require any assumptions regarding either the functional from of the underlying process or the distribution of errors. The coefficient of determination($R^2$), mean absolute deviation(MAD), and the mean squared error(MSE) metrics indicate that neural networks are a viable and can be a superior technique. We also demonstrate that an assessment of the magnitude of the neural notwork input layer cumulative weights can be used to determine the relative importance of predictor variables.

• IE interfaces
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• v.24 no.4
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• pp.323-329
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• 2011

We develop a stochastic model to predict the score of a soccer match. We describe the scoring process of the soccer match as a markovian arrival process (MAP). To do this, we define a two-state underlying Markov chain, in which the two states represent the offense and defense states of the two teams to play. Then, we derive the probability vector generating function of the final scores. Numerically inverting this generating function, we obtain the desired probability distribution of the scores. Sample numerical examples are given at the end to demonstrate how to utilize this result to predict the final score of the match.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.34
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• pp.3-26
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• 2007

Product liability law lies at the center of the modem world. This law concerns liability for damages arising from the commercial sale of a product that causes personal injury or property damage because it was defective or falsely represented. One engaged in the business of selling or otherwise distributing products who sells or distributes a defective product is subject to liability for harm to persons or property caused by the defect. In short, product defectiveness is the heart of products liability law. Regardless of the underlying cause of action, the plaintiff in nearly every products liability case must prove that the defendant's product contained an unnecessary hazard that caused the harm. The purpose of this paper is to clarify the meaning of the product defectiveness to products liability claims in China. In China, Product to include most movable personal property, but to exclude services. And a product is defective when, at the time of sale or distribution, it contains a manufacturing defect, is defective in design, or is defective because of inadequate instructions or warnings.