• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.167-167
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• 1999

In laser ionisation mass spectrometry (LIMS) atoms and molecules which are desorbed from solid surfaces are ionised by an intense laser beam. The photoions which are created are then mass analysed in a time-of-flight mass spectromenter. In best situations, 10% of the ejected particles can be detected, giving the technique^g , pp b sensitivity. Since the ionisation and desorption steps are separated, matrix effects are minimised, in contrast to competitor techniques like SIMS, so quantitation is improved. The talk will illustrate the application of LIMS to basic studies in sputtering in Sr, Cu3Au(100) and Ni3Al(100) as well as ultratrace analysis of Zr in Si.

• Communications for Statistical Applications and Methods
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• v.3 no.2
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• pp.129-138
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• 1996

We propose a smoothing estimator of mean residual life function based on Ghorai and Susarla's (1990) smooth estimator of distribution function under random censorship model and provide the asymptotic properties of this estimator. The Monte Carlo simulation is performed to compare the proposed estimator with the other estimators and an exmple is also given using the real data.

• Communications for Statistical Applications and Methods
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• v.6 no.3
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• pp.939-946
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• 1999

We propose methods for detecting influential observations that have a large influence on the likelihood ratio test statistic for the multivariate Behrens-Fisher problem. For this purpose we derive the influence curve and the derivative influence of the likelihood ratio test statistic. An illustrative example is given to show the effectiveness of the proposed methods on the identification of influential observations.

• Communications for Statistical Applications and Methods
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• v.3 no.2
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• pp.299-307
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• 1996

This article is concerned with the algorithms for the least median of squares estimator. An algorithm based on the $L{\infty}$ .inf.-estimation procedure is proposed in an attempt to improve the optimality of the estimate. And it is shown that the proposed algorithm yields more optimal estimate than the traditional resampling algorithms. The proposed algorithm employs a linear scaling transformation at each iteration of the$L{\infty}$-algorithm to deal with its computational inefficiency problem.

• Communications for Statistical Applications and Methods
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• v.3 no.2
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• pp.13-19
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• 1996

Cook's distance(Cook, 1997) is one of the most widely used influence measures to assess the influence of single observations or sets of observations in the linear regression model. After computing Cook(1977) suggested guidelines based on a confidence ellipsoid for the regression parameter ${\beta}$. In this paper, we suggest cutoff values for Cook's distance cia Monte Carlo simulation, and compare them with Cook's guidelines. An example based on a real data set is given.

• Communications for Statistical Applications and Methods
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• v.6 no.3
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• pp.871-880
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• 1999

The main purpose of queueing theory is to find the optimal solution for maintaining systems such as service facilities. Analyzing the overfolw process provides an important information for the solution in queueing systems with finite capacity. In this thesis we approximate the expected time until the first overflow in M/G/1/K/N queueing systems. Results will be applied to approximate the expected time until the first reduction of source population system. Simulation results show that our approximation is applicable to real situations.

• Journal of the Korean Statistical Society
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• v.3 no.1
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• pp.17-30
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• 1974

There are a number of studies on the peculiarities of inflation in underdeveloped economies. These studies are, however, confined to the cases of Latin American countries, and the essence of methodologies applied in the studies is basically estimations of linear parameters of an extended quantity equation with lagged variables. As it is generally observed, inflation in most of underdeveloped economies are, to some extent, affected by non-economic factors such as political instability, social disorder, abrupt institutional changes, etc. Sometimes, these factors underlying the basic movement of price level change are reflected in such variables as quantity of money supply, income velocity, gross national product.

• Animal Systematics, Evolution and Diversity
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• v.25 no.1
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• pp.5-9
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• 2009

Artotrogus gordoni n. sp. is described as an associate of the bryzoan Schizosmittina cinctipora (Hincks, 1885) collected from an intertidal shore in New Zealand. The new species is similar to A. sardae McKinnon but distinguishable from it by the different shapes of antennule where the first segment is the longest and urosome where the anal somite is distinctly narrower than the genital double somite and posterolateral processes on the genital double somite which is tapered and much more developed than in A. sardae.

• Journal of the Chungcheong Mathematical Society
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• v.32 no.2
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• pp.171-177
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• 2019

We associate a positive integer n and a subgroup H of the group G(n) with a polynomial $J_{n,H}(x)$, which is called the Galois polynomial. It turns out that $J_{n,H}(x)$ is a polynomial with integer coefficients for any n and H. In this paper, we provide an equivalent condition for a subgroup H to provide the Galois polynomial which is irreducible over ${\mathbb{Q}}$.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.57.3-57.3
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• 2020

The chemical and kinematic properties of stars in the Galactic halo provide crucial information on the origin of the Galactic halo as well as the assembly history of the Milky Way. In this study, we present metallicity distribution functions (MDFs) in different regions of the Galactic halo as well as the kinematic characteristics in each region. The different MDFs and kinematic properties of stars in investigated regions allow us to associate them with the possible progenitor dwarf galaxies discovered to date; hence the assembly history of the Galactic halo.