• The Mathematical Education
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• v.43 no.4
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• pp.405-417
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• 2004

This study is on the use of mathematics program for School Mathematics Education. According to the ‘technology principle’ by NCTM and teaching-learning methods by the 7th curriculum, we developed mathematics learning activities with mathematics program. This activity is to construct designs with graphs by using mathematics program(GrafEq.). In this study, we practiced these learning activities with pre-service mathematics teachers. The mathematics educational effects of these learning activities in this study are analyzed as follows; active & spontaneous search for mathematical knowledge, the experience of problem solving, affirmative view-point of mathematics, understanding of practical use of mathematics, acquisition an interest & motivation of learning mathematics etc. When students learn graphs of function, the concept of inequality in secondary school mathematics class., mathematics teachers can make a good use of constructing designs by mathematics program(GrafEq.). This will help to practice of teaching-learning methods by the 7th curriculum.

• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.105-125
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• 2005

Motivated by the field experimental designs in agriculture, the theory of block designs has been applied to several areas such as statistics, combinatorics, communication networks, distributed systems, cryptography, etc. An explicit formula and its fast computational algorithm for a class of symmetric balanced incomplete block designs are presented. Based on the formula and the careful investigation of the modulus multiplication table, the algorithm is developed. The computational costs of the algorithm is superior to those of the conventional ones.

• Journal of the Korean Statistical Society
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• v.15 no.2
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• pp.127-130
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• 1986

Constantine(1981) extended the results of Takeuchi(1961) by adding some new blocks to certain known E-optimal block design. But they are confined to equal blocksize designs. In this paper we agin generalize them to different blocksize case. By augmenting some known E-optimal block designs having blocks of equalsize with blocks of different sizes, additional E-optimal block designs are obtained.

• Communications of the Korean Mathematical Society
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• v.20 no.1
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• pp.15-21
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• 2005

Null designs on the poset of dual polar spaces are considered. A poset of dual polar spaces is the set of isotropic subspaces of a finite vector space equipped with a nondegenerate bilinear form, ordered by inclusion. We show that the minimum number of isotropic subspaces to construct a nonzero null t-design is ${\prod}^{t}_{i=0}(1+q^{i})$ for the types $B_N,\;D_N$, whereas for the case of type $C_N$, more isotropic subspaces are needed.

• Journal of the Korean Statistical Society
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• v.35 no.2
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• pp.201-212
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• 2006

The technique of foldover is usually used by experimenters to de-alias the effects that are interesting in follow-up experiment. Employing a $2^{k-p}$ design with resolution III or higher, Li and Lin (2003) developed an algorithm and used computer programs to search its corresponding optimal foldover design for selected 16-run and 32-run experiments. Based on the minimum aberration criterion, the strong combined-optimal design, defined by Li and Lin, is the better choice of the initial design. In this article, we apply the technique of blocking to find the strong combined-optimal designs. Furthermore, we will tabulate all 16-run and 32-run strong combined-optimal designs and their corresponding core foldover plans for practical use. Some new designs that have not appeared in the other literature but constructed by the technique of blocking are also proposed in this article.

• Journal of the Korean Statistical Society
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• v.34 no.2
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• pp.141-151
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• 2005

Under the assumption that the three-level factors are quantitative, the linear effects are taken more attention than the quadratic effects of the interaction terms. Webb (1971) presented some small incomplete factorial designs that are mixed two- and three-level designs with 20 or fewer runs. The designs provided the estimating linear-by-linear components of interactions between the three-level factors; moreover, they could also offer estimation of interactions that interest the experiments. Webb used ad hoc methods to find these plans; hence, there was still no unified structure to those experiments. In this paper, we develop the methods to construct the $2^{n}3^3$ and $2^{1}3^3$ designs. The designs constructed by these methods not only supply orthogonal estimates of all the main effects but also permit estimation of all the two-factor interactions not involving the quadratic effects. Furthermore, the designs we find are nearly orthogonal.

• School Mathematics
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• v.7 no.4
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• pp.337-352
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• 2005

In this study, we carried out a case study with 38 pre-service mathematics teachers. A theoretical basis of this study is the 'technology principle' by NCTM(2000) and teaching-learning methods by the 7th curriculum. Using mathematics program(Grafeq.), we executed classroom activities for developing materials assisting teaching-teaming for 7th-9th grade mathematics. Pre-service mathematics teachers constructed mathematical designs for each grade by Grafeq. program. We tried to find the results for three research problems. On the basis of observation data, interview data and document materials, we analysed our results as follows. First, our activities help Pre-service mathematics teachers to examine and understand each grade mathematics. Second, we can developamathematicaldesignineachgrade mathematics. Therefore mathematical designs developed in this study can be used middle school mathematics classroom. Third, pre-service mathematics teachers gained the belief that the activities using mathematical in this study can be applied program. effectively to teaching and loaming school mathematics.

• Communications for Statistical Applications and Methods
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• v.14 no.3
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• pp.483-495
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• 2007

In a general fractional factorial design, the n-levels of a factor are coded by the $n^{th}$ roots of the unity. Pistone and Rogantin (2007) gave a full generalization to mixed-level designs of the theory of the polynomial indicator function using this device. This article discusses the optimal blocking scheme for nonregular designs. According to hierarchical principle, the minimum aberration (MA) has been used as an important criterion for selecting blocked regular fractional factorial designs. MA criterion is mainly based on the defining contrast groups, which only exist for regular designs but not for nonregular designs. Recently, Cheng et al. (2004) adapted the generalized (G)-MA criterion discussed by Tang and Deng (1999) in studying $2^p$ optimal blocking scheme for nonregular factorial designs. The approach is based on the method of replacement by assigning $2^p$ blocks the distinct level combinations in the column with different blocks. However, when blocking level is not a power of two, we have no clue yet in any sense. As an example, suppose we experiment during 3 days for 12-run Plackett-Burman design. How can we arrange the 12-runs into the three blocks? To solve the problem, we apply G-MA criterion to nonregular mixed-level blocked scheme via the mixed-level indicator function and give an answer for the question.

• Journal of applied mathematics & informatics
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• v.26 no.3_4
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• pp.563-572
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• 2008

In this paper, we discuss about a generalization of the Key Distribution Pattern which was proposed by C. Mitchell and F. Piper[6]. It is allowing secure communication between every n-pair of users($n\leq2$) in a large network for reducing storage requirements. We further suggest a generalization of K. Quinn's bounds in [9] for the number of subkeys in such general Key Distribution Patterns.

• Journal of the Korean Data and Information Science Society
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• v.14 no.3
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• pp.707-714
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• 2003

Because of complex aliasing, nonregular designs have traditionally been used for screening only main effects. However, complex aliasing actually may allow some interactions entertained and estimated without making additional runs. According to hierarchical principle, the minimum aberration has been used as an important criterion for selecting regular fractional factorial designs. The criterion is not applicable to nonregular designs. In this paper, we give a criterion for choosing fractional factorial designs based on the fan theory. The criterion is focused on the partial ordering given by set inclusion on estimable sets which is called leaves.