• Journal of the Korean Statistical Society
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• v.8 no.1
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• pp.37-64
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• 1979

Criteria and designs are developed for estimating derivatives of P-variable second order polynomial response surfaces. The basic criterion used is mean square error of the estimated derivative, averaged over all directions and then averaged over a region of interest. A new design concept called slope-rotatability is introduced. A simplex optimization program is used to find minimum mena square error designs for the two variable case for $6 \leq N \leq 12$.

• The Korean Journal of Applied Statistics
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• v.29 no.2
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• pp.279-289
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• 2016

Bioequivalence trials based on higher order crossover designs have recently been conducted for highly variable drugs since the Ministry of Korea Food and Drug Safety (MFDS) added new regulations in 2013 to widen bioequivalence limits for highly variable drugs. However, a statistical discussion of higher order crossover designs have not been discussed yet. This research proposes the statistical inference of bioequivalence based on $3{\times}3$ crossover design and discusses it with the MFDS regulations. An illustrated example is also given.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11A
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• pp.891-901
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• 2003

This paper presents low-power asynchronous barrel shifters for variable length encoders and decoders useful in portable applications using multimedia standards. Our approach is to create multi-level asynchronous barrel shifters optimized for the skewed shift control statistics often found in these codecs. For common shifts, data passes through one level, whereas for rare shifts, data passes though multiple levels. We compare our optimized designs with the straightforward asynchronous and synchronous designs. Both pre- and Post-layout HSPICE simulation results indicate that, compared to their synchronous counterparts, our designs provide over a 40% savings in average energy consumption for a given average performance.

• Journal of the Korea Furniture Society
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• v.23 no.1
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• pp.1-9
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• 2012

Sustainable furniture designs are expressed through reutilization, reuse or redesign of the whole of part of natural materials and existing products. These designs contain natural emotions and show those propensities such as uncertainty, integrity, essentiality and experimental natures. Designs that use natural materials such as wood, bamboo, cork, plants, stones and water have sufficient beauty in themselves and thus these materials are not specially processed but their essence is pursued in those designs. Of those materials, the natural material water is used to pursue the essence of aqua while presenting a new furniture design through an experimental method. The circularity of aqua shares its meaning with the circularity of sustainable designs. In addition, the liquidity of aqua will be grafted onto IT technology to express variable shapes in order to present a new direction of furniture designs.

• Structural Engineering and Mechanics
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• v.24 no.4
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• pp.479-491
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• 2006

This paper deals with optimal fibre orientations of symmetrically laminated fibre reinforced composite structures for maximising the fundamental frequency of small-amplitude. A set of fiber orientation angles in the layers are considered as design variable. The Modified Feasible Direction method is used in order to obtain the optimal designs. The effects of number of layers, boundary conditions, laminate thicknesses, aspect ratios and in-plane loads on the optimal designs are studied.

• Journal of the Korean Statistical Society
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• v.5 no.2
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• pp.101-107
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• 1976

One of the important properties of a 'good' response surface design is that the design should be insensitive to wild observations. In this note, a measure of sensitivity to wild observations is studied. It is shown that designs are made robust to wild observations by making $Tr[X'X)^{-1}M]$ small where M is a moment matrix over some region of interest. The proposed criterion is compared with that suggested by Box and Draper. Some about robust two-variable response surface designs are given.

• Communications for Statistical Applications and Methods
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• v.26 no.2
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• pp.175-189
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• 2019

The problem of the estimation of quantitative sensitive variable using the item sum technique (IST) on successive occasions has been discussed. IST difference, IST regression, and IST general class of estimators have been proposed to estimate quantitative sensitive variable at the current occasion in two occasion successive sampling. The proposed new estimators have been elaborated under Trappmann et al. (Journal of Survey Statistics and Methodology, 2, 58-77, 2014) as well as Perri et al. (Biometrical Journal, 60, 155-173, 2018) allocation designs to allocate long list and short list samples of IST. The properties of all proposed estimators have been derived including optimum replacement policy. The proposed estimators have been mutually compared under the above mentioned allocation designs. The comparison has also been conducted with a direct method. Numerical applications through empirical as well as simplistic simulation has been used to show how the illustrated IST on successive occasions may venture in practical situations.

• Journal of the Korean Data and Information Science Society
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• v.25 no.6
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• pp.1181-1193
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• 2014

Currently Ministry of food and drug safety allows add-on trial when the bioequivalence between two drugs fails to show since July 1, 2008. However, bioequivalence of highly variable drugs based on $2{\times}2$ crossover designs would require too many subjects, so the alternative designs like $2{\times}4$ or $2{\times}3$ crossover experiments are preferred. In this paper, we propose and discuss the statistical procedures for add-on trials in $2{\times}4$ and $2{\times}3$ crossover designs.

• Journal of the Korean Society of Clothing and Textiles
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• v.17 no.3
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• pp.475-490
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• 1993

Even though modem ideal body type is rather tall and slim one, most of women don't coincide with it exactly. The objective of this research was to study the optical illusion effect of clothing design line so that average Korean women can approach the modern ideal body type. This research also tried to show the more scientific method to make stimulus by computer simulation and to present quantitative data. For the experiment, 9 design variables were selected from design principal book as follows : waistline level, skirt length, horizontal line emphasis, vertical line emphasis. princess line, vertical stripe, horizontal stripe, diagonal stripe. Each variable was divided into 4 levels so that 36 experimental designs were made. Visual stimuli which same model was wearing each design were recreated by the CAD system. These were given to evaluating panels through slide projecter. Then panels compared experimental design with basic design by 'tall effect' and 'slim effect', All the data from the experiment were analyszed by ANOVA and DUNCAN test for multiple comparison to study significance, direction(positive or negative), degree, proper extent of optical illusion effect. The result showed that some designs have optical illusion effect to make better look. In addition, it proved that the stronger design variable does not mean the more optical illusion effect and there was proper extent which produce the best illusion effect in each design variable.

• Journal of Korean Society for Quality Management
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• v.45 no.4
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• pp.943-956
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• 2017

Purpose: This paper proposes a VSS(Variable Sample Size) ${\bar{X}}$ control chart using surrogate variable and shows its effectiveness compared with FSS(Fixed Sample Size) ${\bar{X}}$ control chart using either performance variable or surrogate variable. Methods: The expected cost function of VSS ${\bar{X}}$ control chart is derived. The optimal designs are then found for numerical examples using a GA(genetic algorithm) and compared to those of the FSS ${\bar{X}}$ control charts. Results: Computational results show that VSS ${\bar{X}}$ control chart using surrogate variables is superior to FSS ${\bar{X}}$ control chart using either performance variable or surrogate variable from the economic view points. Conclusion: The proposed VSS ${\bar{X}}$ control chart will be useful in industry fields where a performance variable is not avaliable or too costly.