• Honam Mathematical Journal
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• v.42 no.2
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• pp.213-218
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• 2020

Assume that K is a number field and K_ur is the maximal unramified extension of it. When Gal(K_ur/K) is an infinite group. It is known that Gal(K_ur/K) is generated by finitely many Frobenius classes of Gal(K_ur/K) by Y. Ihara. In this paper, we will give the explicit number of Frobenius classes which generate whole group Gal(K_ur/K).

• Journal of the Korea Computer Industry Society
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• v.2 no.10
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• pp.1301-1308
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• 2001

In this paper, some interesting aspects of Grzegorczyk classes $\xi\sum{n}$, n$\geq$0 & $\sum$= { 1, 2 } of word-theoretic primitive recursive functions are observed including the classes of its corresponding predicates ($\xi\sum{n}$)* In particular, the small classes $\xi\sum{n}$($n\leq2$) are very incomparable to the corresponding small classes $\xi\sum{n}$ where $\xi\sum{n}$ is the number-theoretic Grzegorczyk classes. As one of some interesting aspects of the small classes, we show that the equivalence problem in $\xi\sum{0}$is undecidable.

• Journal of Technologic Dentistry
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• v.23 no.2
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• pp.17-47
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• 2002

The purpose of this study was to examine the 2001 curricula in 17 departments of dental technology across the nation in an attempt to find out the educational realities of the departments by term and school year and serve as a basis for the development of more advanced, efficient dental technology curriculum and common educational objectives. For that purpose, the 2001 curricula of the three-year dental laboratory technology departments were analyzed by school year and term to calculate the amount of required credit, the number of subjects, and the weekly classes for electives and major. The findings of this study could be listed as below: 1. The departments of dental laboratory technology nationwide investigated require students to get 120 to 135 credits in total. Out of the credits, 10 to 25 credits are assigned to the electives, and 106 to 11 8 credits are given to the major. 2. There are 50 to 68 subjects in the departments of dental technology. 5 to 16 subjects are the electives, and 41 to 59 are the major. 3. There are 150 to 196 classes per week, which consist of 10 to 30 ones for the electives and 137 to In for the major. 4. The curricula for the first semester of the first year are as follows: 1) 20 to 24 credits are required. 4 to 11 credits are alloted to the electives, and 9 to 19 credits are assigned to the major. 2) The number of subject is 9 to 13, which are composed of 2 to 7 for the electives and 4 to 9 for the major. 3) The weekly classes are 22 to 29. The classes for the electives range from 4 to 14 per week, and 10 to 20 classes a week are for the major. 5. The curricula for the second semester of the first year are as below: 1) There are 20 to 25 credits. 3 to 12 credits are assigned to the electives, and 12 to 19 credits are for the major. 2) The number of subject is 10 to 14, which consist of 2 to 6 for the electives and 6 to 10 for the major. 3) The weekly classes are 22 to 29. and 3 to 12 classes a week are for the electives, and 15 to 24 classes are for the major. 6. The curricula for the first semester of the second year are as below: 1) The number of credits ranges from 20 to 24. Only six colleges offer 2 credits for the electives and the major account for 18 to 24 ones. 2) There are 8 to 12 subjects. Only six colleges offer one or two electives, and 8 to 12 are the major. 3) The weekly classes are 23 to 33. Only six colleges offer 2 or 3 classes a week for the electives, and 21 to 33 classes are for the major. 7. The curricula for the second semester of the second year are as below: 1) The number of credits ranges from 19 to 24. Only two colleges offer 2 credits for the electives and the major account for 18 to 24 ones. 2) There are 7 to 12 subjects. Only two colleges offer one or two electives, and 8 to 12 are the major. 3) The weekly classes are 24 to 36. Only two colleges offer 2 classes a week for the electives, and 24 to 36 classes are for the major. 8. The curricula for the first semester Of the third year are as below: 1) There are 16 to 24 credits. Just a college assigns 2 credits to the electives, and 16 to 24 credits are given to the major. 2) The number of subject is 5 to 12. Only a college offers one elective for optional course, and 5 to 12 are the major. 3) The weekly classes range from 18 to 39. Just a college offer 2 classes a week for the electives, and 18 to 39 classes are for the major. 9. The curricula for the second semester of the third year are as below: 1) There are 16 to 23 credits. Just a college assigns 2 credits to the electives, and 16 to 23 credits are given to the major. 2) The number of subject is 5 to 12. Only a college offers one elective for optional course, and 5 to 12 are the major. 3) The weekly classes range from 18 to 39. Just a college offer 2 classes a week for the electives, and 18 to 39 classes are for the major.

• Journal of Integrative Natural Science
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• v.13 no.1
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• pp.19-26
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• 2020

In this paper, we study on the reinterpretation of Burnside's theorem that is a tool to compute the number of equivalence classes of a group action on a set, and by applying it, we find out the numbers of different patterns in coloring problems of various types of figures with symmetry and use them for computing the numbers of different kinds of chemical compounds.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.3
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• pp.73-83
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• 2003

Methods of fuzzy C-means have been used to characterize geotechnical information from static cone penetration data. As contrary with traditional classification methods such as Robertson classification chart, the FCM expresses classes not conclusiveness but fuzzy. The results show that the FCM is useful to characterize ground information that can not be easily found by using normal classification chart. But optimal number of classes may not be easily defined. So, the optimal number of classes should be determined considering not only technical measures but engineering aspects.

• Journal of the Korean Statistical Society
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• v.10
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• pp.122-127
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• 1981

A parallel flats fraction for the $3^n$ factorial is symbolically written as $At=C=(C_1 C_2 \cdots C_f)$ where C is a rxf matrix and A is rxn matrix with rank r. It is shown that the set of all possible parallel flats fraction C for a given A and given size can be partitioned into equivalence classes. The number of those classes are enumerated in general.

• Korean Journal of Remote Sensing
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• v.20 no.5
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• pp.353-359
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• 2004

This study proposes an approach to unsupervisedly estimate the number of classes and the parameters of defining the classes in order to train the classifier. In the proposed method, the image is segmented using a spatial region growing based on hierarchical clustering, and fuzzy training is then employed to find the sample classes that well represent the ground truth. For cluster validation, this approach iteratively estimates the class-parameters in the fuzzy training for the sample classes and continuously computes the log-likelihood ratio of two consecutive class-numbers. The maximum ratio rule is applied to determine the optimal number of classes. The experimental results show that the new scheme proposed in this study could be used to select the regions with different characteristics existed on the scene of observed image as an alternative of field survey that is so expensive.

• Journal of the Korean Institute of Educational Facilities
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• v.8 no.5
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• pp.5-16
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• 2001

This paper presents results from analysis of architectural plan drawings of 355 elementary schools recently designed for 4 years. Theses plans are analyzed by factors such as local distribution, number of classes, type of plan, total construction area, area per a class, area per a student, and area status of each space. The purpose of this study is to provide fundamental resources for architectural designing and planning of elementary schools through finding trend and status of elementary school buildings that have no detailed data of area index. The results of this study are as follows: 1. As a result from analyzing number of classes in the surveyed schools, schools having 36 classes are dominant and schools having 72 classes are also shown. Average number of classes is 34.1. This result reflect s that elementary schools have been planned as large-scale schools. 2. In terms of type of plan, we found out that instead of disappearing traditional single corridor type building, the open school building that have multi-purpose spaces are mainly designed. In addition to that, there are few schools with large class rooms. 3. In the status of area of each school, they have much larger areas than areas provided by building guidelines. Secondly, there are some schools with two times area difference even though they have same class number. Therefore, it needs to adjust the school building guidelines to practical needs in the consideration of elementary school building for compulsory education. Though the plans of recently designed school for 4 year s are more differentiated than past, there are few schools planned by appropriate plan design and area distribution scheme. As a consequence, some improvements like improvement of building guidelines are desperate.

• Journal of the Chungcheong Mathematical Society
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• v.22 no.3
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• pp.299-307
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• 2009

We count the isomorphism classes of elliptic curves over finite fields $\mathbb{F}_{3^{n}}$ and list a representative of each isomorphism class. Also we give the number of rational points for each supersingular elliptic curve over $\mathbb{F}_{3^{n}}$.

• Journal of Advanced Information Technology and Convergence
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• v.10 no.2
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• pp.177-197
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• 2020

Colleges have been forced to take non-face-to-face classes this year due to the COVID-19, and the situation is expected to continue unless the development of treatments and vaccines is carried out as soon as possible. In the situation where non-face-to-face classes are required under compulsion, two methodologies have been suggested as most representative alternatives to face-to-face classes: online real-time classes and on-demand contents classes. The purpose of this study is to compare the perceived convenience, self-fidelity, and preference of students between online real-time and on-demand contents classes by gender, school year grade, mostly using class media, and number of courses taken. Comparative results between online real-time and on-demand contents classes were statistically analyzed by surveying students at a university.