• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.2
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• pp.11-20
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• 2002

In this paper, for many prime power q, it is shown that new cyclic relative difference sets with parameters (equation omitted) can be constructed by using d-homogeneous functions on $F_{q^{n}}${0} over $F_{q}$ with difference-balanced property, where $F_{q^{n} }$ is a finite field with $q^{n}$ elements. Several new cyclic relative difference sets with parameters (equation omitted) are constructed by using p-ary sequences of period $q^{n}$ -1 with ideal autocorrelation property introduced by Helleseth and Gong and d-form sequences.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.4
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• pp.593-601
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• 2016

This study was carried out to establish an effective marketing strategy based on Importance-Performance Analysis (IPA) of rice-convenience foods. IPA is one of the most efficient and simple methods to evaluate product quality. Data were collected from 652 people (320 males and 332 females) and analyzed by SPSS 19.0. Subjects consumed rice-convenience foods as a snack substitute (19.3%), breakfast (20.7%), lunch (37.4%), dinner (15.2%), and late-night meal (7.4%). The purpose for consumption of rice-convenience foods were as follows: light meal (34.8%), lack of time to prepare meal (42.2%), favorite restaurant is not nearby (2.3%), save money (3.4%), and outdoor activities (9.7%). All attributes about rice-convenience foods were categorized into intrinsic property and extrinsic property. As a result of factor analysis, health, sensibility, and diversity factors were extracted from intrinsic property. In addition, dependence and appearance factors were drawn from extrinsic property. In analyzing the differences between importance and performance, there were significant differences; 16 items in the intrinsic property (P<0.01), and 10 items in the extrinsic property (P<0.001). The IPA matrix is composed of four quadrants, and each represents different strategies; the first, 'keep up the good work', the second, 'possible overkill', the third, 'low priority for management', and the fourth, 'concentrate management'. As a result, factors of rice-convenience foods positioned in the fourth quadrant were 'safety (from food additives, etc.)' and 'price' in the intrinsic property and 'nutrition label' and 'safety of packaging material' in the extrinsic property. They need to be improved immediately. In this study, rice-convenience food factors for continuous maintenance and concentrative improvement were compared by IPA. Based upon the results of this study, it is necessary to develop methods to make efficient use of limited resources and practical marketing strategies.

• Polymer(Korea)
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• v.34 no.1
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• pp.79-83
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• 2010

Alginate beads were prepared using poly(N-isopropylacrylamide-co-dimethylamino ethyl methacrylate)(P(NIPAM-co-DMAEMA)). First, P(NIPAM-co-DMAEMA) was immobilized on the surface of alginate beads by taking advantage of electrostatic interaction between alginate and P(NIPAM-co-DMAEMA). Second, P(NIPAM-co-DMAEMA) was contained in the matrix of alginate beads. P(NIPAM-co-DMAEMA) were prepared by a free radical polymerization at $74^{\circ}C$ for 12 h. The weight ratio of NIPAM to DMAEMA monomer was 95/5. The copolymer was identified by $^1H$-NMR. Releases from the alginate beads were observed at 30, 37, and $45^{\circ}C$ using blue dextran or FITC-dextran(fluorescein isothiocyanate-dextran) as a model drug. The effect of temperature on the degree of release from the beads was insignificant. FITC-dextran was released more than blue dextran possibly due to its smaller molecular weight.

• Journal of the Korean Statistical Society
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• v.22 no.2
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• pp.259-269
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• 1993

A moving average model, LMA(q) and an autoregressive-moving average model, NLARMA(p, q), with Laplacian marginal distribution are constructed and their properties are discussed; Their autocorrelation structures are completely analogus to those of Gaussian process and they are partially time reversible in the third order moments. Finally, we study the mixing property of NLARMA process.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1226-1228
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• 1995

This paper introduced foreign standard testing methods on composite insulators(for transmission, distribution) and mentioned on (1)evaluation of material property (2)short-term test of prototype (3)insulation efficiency on use to evaluation property of insulators made of composite insulating materials.

• Journal of applied mathematics & informatics
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• v.30 no.3_4
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• pp.677-683
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• 2012

W.Choi([1]) obtains a complete description of ergodic property and several property by making use of the semigroup method. In this note, we shall consider separately the martingale problems for two operators A and B as a detail decomposition of operator L. A key point is that the (K, L, $p$)-martingale problem in population genetics model is related to diffusion processes, so we begin with some a priori estimates and we shall show existence of contraction semigroup {$T_t$} associated with decomposition operator A.

• Journal of applied mathematics & informatics
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• v.31 no.1_2
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• pp.241-246
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• 2013

Choi [1] identified and characterized the limiting diffusion of this diploid model by defining discrete generator for the rescaled Markov chain. In this note, we define the operator of projection $S_t$ on limiting diffusion and new measure $dQ=S_tdP$. We show the martingale property on this operator and measure. Also we conclude that the martingale problem for diffusion operator of projection is well-posed.

• Communications for Statistical Applications and Methods
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• v.24 no.5
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• pp.443-455
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• 2017

In this paper, we study ARCH(${\infty}$) models with either geometrically decaying coefficients or hyperbolically decaying coefficients. Most popular autoregressive conditional heteroscedasticity (ARCH)-type models such as various modified generalized ARCH (GARCH) (p, q), fractionally integrated GARCH (FIGARCH), and hyperbolic GARCH (HYGARCH). can be expressed as one of these cases. Sufficient conditions for $L_2$-near-epoch dependent (NED) property to hold are established and the functional central limit theorems for ARCH(${\infty}$) models are proved.

• Communications of the Korean Mathematical Society
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• v.11 no.4
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• pp.967-974
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• 1996

We discuss contraction operators T in the class A, where A is the class of absolutely continuus contractions for which the Sz.-Nagy-Foias functional calculus is isometry. We obtain relationship between the class $A_{n, \aleph_0}$ and hereditary property $(\tilde{P}_n)$.

• Communications of the Korean Mathematical Society
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• v.29 no.4
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• pp.569-579
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• 2014

We consider a condition under which the projectivization $P(E^k)$ of a complex k-bundle $E^k{\rightarrow}M$ over an even-dimensional manifold M can have the hard Lefschetz property, affected by [10]. It depends strongly on the rank k of the bundle $E^k$. Our approach is purely algebraic by using rational Sullivan minimal models [5]. We will give some examples.