• 대한수학회보
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• 제57권3호
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• pp.623-647
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• 2020

The greatest integer that does not belong to a numerical semigroup S is called the Frobenius number of S. The Frobenius problem, which is also called the coin problem or the money changing problem, is a mathematical problem of finding the Frobenius number. In this paper, we introduce the Frobenius problem for two kinds of numerical semigroups generated by the Thabit numbers of the first kind, and the second kind base b, and by the Cunningham numbers. We provide detailed proofs for the Thabit numbers of the second kind base b and omit the proofs for the Thabit numbers of the first kind base b and Cunningham numbers.

• 한국콘텐츠학회논문지
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• 제17권4호
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• pp.375-383
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• 2017

헌법재판소는 2015년 12월, 주민등록번호 변경을 허용하지 않는 주민등록법 제7조에 대하여 헌법불합치 결정을 내렸다. 그런데 주민등록번호를 개편하는데 가장 문제가 되는 것은 국민들의 불편 비용이다. 주민등록번호를 변경할 때는 주민들이 이미 외워서 사용하고 있는 주민등록번호를 새로 외워야 하는데, 이에 대한 불편 비용이 가장 큰 비용일 것으로 추정하고 있다. 하지만 이 불편 비용이 어느 정도일지에 대해서는 제대로 파악이 되지 못하고 있다. 이에 본 연구에서는 주민등록번호를 개편하는데 대한 국민들의 불편 비용이 어느 정도일지를 추정해보고자 한다. 분석 결과 주민등록번호 13자리를 모두 변경할 경우 불편 비용은 16만 원, 주민번호 뒤 7자리를 변경할 경우의 불편 비용은 10만 8천 원, 세컨 번호 도입시의 불편 비용은 11만 원 정도로 추산되었다. 이 불편 비용은 다른 비용 및 편익 요소들과 같이 포함되어 주민등록 변경 안에 대한 비용편익 분석에 활용될 수 있을 것이다.

• 한국가정과교육학회지
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• 제10권2호
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• pp.87-99
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• 1998

The purposes of the study are to see as to how much of changes has occurred in the newly revised high school Home Economics Textbooks required by the 6th Curriculum and to seek future policy directions which can be improved even better, if any, for further revision. To implement this proposal, the study employs 6 different textbooks published in 1996 geared for the 6th Curriculum for data base. The components of the contents divides into two major parts. The first part faUs into a category of holistic analysis of the textbooks, which gives a general perspective of the changes in the textbook revised. It includes those areas of changes in the total number of pacover page, illustrations, table of contents, appendices, unit cover, introductory remarks, summary and evaluation, etc. It also covers the information on authors of textbook. The latter part consists of several specific areas of major changes occurred in the textbooks for the 6th Curriculum. It covers such areas of changes in the composition of category and its weigh laboratory experiences, and illustrations and tables. To conclude the study, there found followings key features : 1) The new textbooks have adopted more of varieties in physical appearances and contents per se as to the older ones. And yet, there still found a weakness in numbers of authors participated to a full reflection of contents variety. In addition, the background of authors reflected on an unrealistic idealism which lacks the on-site information provided by the school teachers. 2) The content area consists of 3 major areas of Human Development & Family Relationship. Food and Nutrition. Clothing and Textiles with ratio of 23.8%, 23.1%, and 21.9% respectively. 3) Human Development & Family Relationship area ranked first with 71 times in the numbers of laboratory activities for each content area. followed by Food and Nutrition with 56 and Family Resorces & Consumerism with 54. These increased numbers of laboratory activities in textbooks represent the changing contents of Home Economics and imply the desirable and positive directions of Home Economics education in Korea. numbers of laboratory activities for each content area. followed by Food and Nutrition with 56 and Family Resorces & Consumerism with 54. These increased numbers of laboratory activities in textbooks represent the changing contents of Home Economics and imply the desirable and positive directions of Home Economics education in Korea.

• 소음진동
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• 제8권2호
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• pp.297-305
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• 1998

The finite element method is used for the study of the eigenvalue problems of partially fixed end beams with intermediate elastic supports. The elastic critical loads and natural frquencies of the beams are investigated by changing the numbers of elastic supports and their stiffness, and also by changing Kinney's fixity factor, $f_a$. The relationship between two eigenvalues is established by calculating the corresponding values of $(w/w_n)^2$ through changing $(P/P_{cr})$ values. The results of this study are as follows : (1) The elastic critical loads and natural frequencies of beams increase with increases in Kinney's fixity factor, $f_a$ and with the increased numbers of intermediate elastic supports. (2) The relationship between elastic critical loads and the natural frequencies of partially fixed end beams with intermediated elastic supports is $P/P_{cr} + (w/w_n)^2/ = 1$ without regard to Kinney's fixity factor, the stiffness of elastic supports, or the number of elastic supports.

• East Asian mathematical journal
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• 제25권3호
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• pp.247-262
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• 2009

Permutation and combination are the part of mathematics which can be introduced the pliability and diversity of thought. In prior studies of permutation and combination, there treated difficulties of learning, strategy of problem solving, and errors that students might come up with. This paper provides the method so that meaningful teaching and learning might occur through the systematic approach of permutation and combination. But there were little prior studies treated counting numbers that basic of mathematics' action. Therefore this paper tries to help the understanding of permutation and combination with the process of changing from informal knowledge to formal knowledge.

• Nuclear Engineering and Technology
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• 제44권3호
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• pp.283-296
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• 2012

The natural convection in a horizontal enclosure heated from the bottom wall, cooled at the top wall, and having a square adiabatic body in the center is studied. Three different Prandtl numbers (0.01, 0.7 and 7) are considered for the investigation of the effect of the Prandtl number on natural convection. Adiabatic boundary conditions are employed for the side walls. A two-dimensional solution for unsteady natural convection is obtained, using an accurate and efficient Chebyshev spectral methodology for different Rayleigh numbers varying over the range of $10_3$ to $10_6$. It had been experimentally reported that the heat transfer mode becomes oscillatory when Pr is out of a specific Pr band beyond the critical Ra. In this study, we reproduced this phenomenon numerically. It was found that when Ra=$10_6$, only the case for intermediate Pr (=0.7) reached a non-changing steady state and the low and high Pr number cases (Pr=0.01 and 7) showed a periodically oscillatory fashion hydrodynamically and thermally. The variation of time- and surface-averaged Nusselt numbers on the hot and cold walls for different Rayleigh numbers and Prandtl numbers are presented to show the overall heat transfer characteristics in the system. Further, the isotherms and streamline distributions are presented in detail to compare the physics related to their thermal behavior.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.107-110
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• 2002

The optical memory devices of BST thin films to composite $(Ba_{0.7}\;Sr_{0.3})TiO_{3}$ using sol-gel method were fabricated by changing of the depositing layer number on $Pt/Ti/SiO_{2}/Si$ substrate. The structural properties of optical memory devices to be ferroelectric was investigated by fractal analysis and 3-dimension image processing. The thickness of BST thin films at each coating numbers 3, 4 and 5 times was $2500[\AA]$, $3500[\AA]$ and $3800[\AA]$. BST thin films exhibited the most pronounced grain growth. The surface morphology image was roughness with coating numbers. The thin films increasing with coating numbers shows a more textured and complex configuration.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.875_876
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• 2009

Recently, Interior Permanent Magnet Synchronous Motor(IPMSM) is widely used in the industry applications such as power train for hybrid vehicles and compressor motors of air-conditioner due to its high power density and wide speed range. There are some ways for confirming of maximum power in IPMSM. However, This paper suggests that there is a way about making sure maximum power by reducing turn numbers of armature winding. Setting up the voltage equation through the equivalent circuit and vector diagram of IPMSM first, and then estimating the parameter and power of IPMSM by changing the turn numbers of armature winding and voltage. In order to satisfy output power, the turn numbers of armature winding is changed by using the characteristic analysis, and then checking whether secure maximum power or not.

• Journal of Preventive Medicine and Public Health
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• 제14권1호
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• pp.39-42
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• 1981

Recent changes in the cause of death among the Korean population seem to be systematic and significant. Data on cause of death from the medically certified death certificates provide at least four types of evidence: a sudden increase in recent years in the numbers of death due to cerebrovascular disease or circulatory diseases including rheumatic fever and chronic heart diseases and atherosclerosis; increasing steadily in the numbers of death due to malignant neoplasm of various sites, and death due to accident; decreasing steadily in the numbers of death due to communicable diseases or parasite diseases; and a large number of deaths with unspecified symptoms and ill-defined conditions. The lack of complete registration of the deads occurred or the incomplete description on the cause of death reported suggests that statistical information of cause of death from the medically certified death records is meaningful in interpreting changing patterns.

• 한국가정과교육학회지
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• 제8권2호
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• pp.65-79
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• 1996

This study proposes a model curriculum for Vocational Home Economics High School in the 7th Curriculum Revision. The model in the study is first drawn from the assumptions that reflect ever changing demands of industrial society for Home Economics education. Another perspective employed in the study is historical analysis that focuses on the evolution of the Vocational Home Economics Curricula from the 1st through the 6th revision. This study also employes comparative research tools for the national level comparison such as USA, Japan, Taiwan, and Korea. The proposed model curriculum in this study is concluded from those step-by-step studies as follows：1) Problem definition and design in current curriculum for Vocational Home Economics high school； 2) Needs and roles analysis of Vocational Home Economics high school for the future； and 3)Historical analysis of our curriculum revisions in the past and coparative analysis with other countries. Authors conducted this research project for 3 month period from June 15, 1996 to September 15, 1996. During this period, authors collected the data and information through those method as an extensive literature review, survey and interview, and curriculum specialist conference. The key and critical features of the proposed curriculum in the study are as follows：1) In the numbers of department, a proposed model curriculum offers 8 as opposed to 6 in the 6th revision, reflecting two additional departments of “Elderly Welfare”and “Cosmotology”. 2) In the statement of educational objectives, a model curriculum emphasizes a more concrete statement to each specific skills according to the changing societal needs. 3) In the numbers of total subject matters, there would be 40 in the new as opposed to 23 in the current curriculum. Among these changes, 17 would occurr in the newly introduced subject matters, while 11 would simply change the subject matter name. Among 40 subject matter, “Introduction to Computer” and “Home Economics in Vocational Education”would be required subject matter. 4) In the total numbers of required unit for graduation in three years, a model offers 86∼132 unit. A maximum unit for each subject matter would be 12.