• Korea journal of population studies
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• v.13 no.1
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• pp.26-36
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• 1990

본 연구는 1975년에서 1985년에 걸쳐 노년인구의 전체인구에 대한 상대적 비율 및 그 변화를 시도 단위의 지역적 차이에 역점을 맞추어 고찰한다. 노년인구의 비율에 변화를 준 사망, 출산 및 인구 이동의 인구 과정을 65세 이상의 노년인구와 65세 미만의 비노년인구의 순인구이동과 자연증가 개념으로 통합하여 분석한다. 1975-1980년, 1980-1985년 두 기간동안 서울 부산 및 경기도는 다른 지역에 비해 노년인구의 비율이 상대적으로 낮았으며 모든 지역이 동 기간동안 노년인구비율의 증가를 경험했지만 이러한 변화에 관련된 인구 과정의 영향은 노년인구의 비율을 지속적으로 증가시키는데 반해, 노년인구의 자연증가 영향은 1980년을 기점으로 커다란 대조를 이루어 1980년 이후에만 노년인구화를 증가시킨다. 특히, 1980-1985년 동안 비노년인구의 인구이동이 서울,부산 및 경기도의 노년비율은 감소시키고 타 지역의 비율은 증가시켜 모든 지역에서 노년인구비율의 변화를 결정하는 주요 요인으로 작용하였다. 비 노년인구인구의 이ㄷ오과는 다른 대상을 나타내는 노년인구의 인구 이동 역시 지역의 노년인구비율에 다양한 영향을 주었다. 끝으로 노년인구의 인구이동 및 노년인구의 집중현상에 수반되는 사회적 결과를 논의한다.

• Journal of Elementary Mathematics Education in Korea
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• v.19 no.4
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• pp.485-499
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• 2015

In this paper, focusing on definitions of terms related to ratio (a:b, external ratio, internal ratio, percentage, proportion, bi-ui-gap(value of a:b)), elementary school mathematics textbooks of Korea and Japan are compared. We can find significant differences between Korean and Japanese textbooks. In Korean textbook, 'bi-yul' includes both of the internal ratio and the external ratio. In Japanese textbooks, the external ratio(amount of unit size) and the internal ratio(wariai) are defined independently. And a:b is set to a subconcept of the internal ratio. In addition, a:b and percentage are presented as methods to express the internal ratio. From these results, the following four implications for developing our mathematics textbooks can be presented as conclusions. First, it is necessary to limit the ratio to mean the internal ratio. Second, it is necessary to define connotatively the ratio as the internal ratio and to set it as a prior concept of a:b. Third, it is necessary to define 1% as the internal ratio 0.01. Fourth, it is necessary to define bi-ui-gap as a number for expressing a:b, when viewing a:b as the expression method of the internal ratio.

• Journal of Elementary Mathematics Education in Korea
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• v.21 no.1
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• pp.135-160
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• 2017

Since mathematics textbooks for 6th graders based on the 2009 revised national curriculum were applied to the site, there has been a note pointing out that the unit of 'ratio and rate' causes some learning difficulties. This implies the necessity of search for desirable methods of organizing the unit of ratio and rate in mathematics textbooks. This study analyzed and compared Korean and foreign mathematics textbooks on ratio and rate longitudinally and horizontally, respectively. For longitudinal analysis, we selected the mathematics textbooks according to the national curriculum since the 5th one. For horizontal analysis, we took the mathematics textbooks of Japan, Singapore, Hong Kong, and Finland. In each textbook, the contents and the order in relation to ratio and rate, the definitions of terminology, and the methods for introducing related concepts are set as the analysis framework. The results of analysis revealed many characteristics and the differences in ways of dealing contents about ratio and rate. Based on these results, we suggested some implications for writing the unit of ratio and rate in elementary mathematics textbooks.

• Journal of Educational Research in Mathematics
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• v.23 no.2
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• pp.285-295
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• 2013

In this study I examine the definitions of terms related to ratio and rate from 5, 6, 7th revised elementary school math textbooks to discuss the improvements and the remained problems in 2007 curriculum textbook. Next, I make the alternative definitions of the terms, 'biyoul', the value of 'bi', and 'baekboonyul' by re-establishing the relations between them. Finally, I point out that those problems are intrinsic to the attempt of the textbook to introduce the terms related to ratio with little consideration for the mathematical meaning of ratio as a equivalence class.

• Journal of Elementary Mathematics Education in Korea
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• v.19 no.3
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• pp.371-386
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• 2015

There has been little consensus on how to define and use the Korean mathematical terms, bi-ui-gap and bi-yul. This study compares four perspectives of bi-ui-gap and bi-yul proposed and discussed in Korean mathematics education community and examines the ways of using the terms adopted since the 6th national curriculum. Based on the analysis that previously proposed perspectives conflict each other, this study proposes as a way to synthesize different perspectives of bi-ui-gap and bi-yul by analyzing the terms in the internal and external ratio contexts. This study proposes that bi-ui-gap be used to represent 'a value of $A{\div}B$' rather than 'a value originated from a ratio A:B' or 'a fraction form ${\frac{B}{A}}$.' This study also proposes that bi-yul or bae-yul be used in the internal ratio context and a new term, such as dan-wi-yul, be created for the external ratio context.

• Proceedings of the KSLP Conference
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• 1997.11a
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• pp.253-253
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• 1997

비폐색이 있는 경우 음성이 변하는 것을 쉽게 느낄 수 있지만, 비폐색 때의 음향학적인 특성에 대하여 알려진 바를 찾기는 쉽지 않다. 저자들은 인위적으로 비폐색을 유발하여 비폐색 부위에 따른 비강자음의 음향학적 변화특성을 파악하고 비음도의 변화 정도를 비교하고자 하였다. 정상비음도를 보이는 성인남녀 각 10명을 대상으로, 2ml의 부피를 갖도록 수술용장갑에 Merocel$^{\circledR}$을 넣은 뒤, 이를 이용하여 ostiomeatal unit(OMU)을 중심으로 전후상하 4부위의 인위적인 비폐색을 유발하여, 비폐색 전과 후의 부위에 빠른 차이틀 비교하였다. /나나/의 발성을 각 조건에서 3회 실시하여, 모음중간의 /ㄴ/중 (CVCV) 안정된 spectorgram소견을 보이는 부위를 선택하여, 해당구간의 제1, 제2, 제3 음형대와 각각의 bandwidth 평균값을 남녀별로 비교하였고, 표준비음비율이 알려진 rabbit, baby, mama 문장을 이용하여 비음비율을 비교하였다. 남녀모두 비폐색전에 비하여 OMU의 앞쪽부위를 막은 경우에 제1음형대가 가장 뚜렷하게 감소되었으며, 비음비율의 유의한 감소를 보였다. 비폐색이 있는 경우, 비강자음 /ㄴ/은 제1음형대를 중심으로 주요변화가 일어남을 알 수 있었으며, 비폐색 부위에 따라 비음비율이나 제1음형대 감소의 정도가 다름을 알 수 있었다.

• Journal of Educational Research in Mathematics
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• v.18 no.3
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• pp.309-333
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• 2008

In this research, we reconstructed the textbook on the concept of rate and ratio, which is based on the review on the previous researches and the analysis on the elementary textbook of the 7th mathematics curriculum. We conducted the teaching experiment using the reconstructed textbook, which is to identify the students' conception of rate and ratio and the appropriateness and limit of the reconstructed textbook. As the results of this study, we identify that the changed sequence of instruction (that is, ratio ${\rightarrow}$ percent and value of rate ${\rightarrow}$ rate) was very proper to help students understand the concept of rate and ratio. The relative comparison and absolute comparison and the additive thinking and multiplicative thinking included in the reconstructed textbook were identified very helpful to students' understanding. Meanwhile some contexts given in the reconstructed textbook were identified to cause the students' cognitive confusions.

• School Mathematics
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• v.17 no.4
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• pp.613-632
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• 2015

In this study, we hope to reveal teacher knowledge necessary to address student errors and difficulties about ratio and rate. The instruments and interview were administered to 3 in-service primary teachers with various education background and teaching experiments. The results of this study are as follows. Specialized content knowledge(SCK) consists of profound knowledge about ratio and rate beyond multiplicative comparison of two quantities and professional knowledge about the definitions of textbook. Knowledge of content and students(KCS) is the ability to recognize students' understanding the concept and the representation about ratio and rate. Knowledge of content and teaching(KCT) is made up of knowledge about various context and visual models for understanding ratio and rate.

• Journal of Elementary Mathematics Education in Korea
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• v.21 no.1
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• pp.215-241
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• 2017

This study analyzed teachers' Pedagogical Content Knowledge (PCK) regarding the pedagogical aspect of the instruction of ratio and rate in order to look into teachers' problems during the process of teaching ratio and rate. This study aims to clarify problems in teachers' PCK and promote the consideration of the materialization of an effective and practical class in teaching ratio and rate by identifying the improvements based on problems indicated in PCK. We subdivided teachers' PCK into four areas: mathematical content knowledge, teaching method and evaluation knowledge, understanding knowledge about students' learning, and class situation knowledge. The conclusion of this study based on analysis of the results is as follows. First, in the 'mathematical content knowledge' aspect of PCK, teachers need to understand the concept of ratio from the perspective of multiplicative comparison of two quantities, and the concept of rate based on understanding of two quantities that are related proportionally. Also, teachers need to introduce ratio and rate by providing students with real-life context, differentiate ratios from fractions, and teach the usefulness of percentage in real life. Second, in the 'teaching method and evaluation knowledge' aspect of PCK, teachers need to establish teaching goals about the students' comprehension of the concept of ratio and rate and need to operate performance evaluation of the students' understanding of ratio and rate. Also, teachers need to improve their teaching methods such as discovery learning, research study and activity oriented methods. Third, in the 'understanding knowledge about students' learning' aspect of PCK, teachers need to diversify their teaching methods for correcting errors by suggesting activities to explore students' own errors rather than using explanation oriented correction. Also, teachers need to reflect students' affective aspects in mathematics class. Fourth, in the 'class situation knowledge' aspect of PCK, teachers need to supplement textbook activities with independent consciousness and need to diversify the form of class groups according to the character of the activities.

• Journal of Educational Research in Mathematics
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• v.20 no.3
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• pp.397-411
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• 2010

In this paper, definitions of biyoul and value of bi in elementary mathematics in Korea are critically analysed. And identity of halpunri is reviewed. Regarding biyoul, it is suggested that the use of term 'biyoul' is restricted to such cases when the quantity to be compared and the quantity to be a base have same measuring unit, without consider ing biyoul in terms of two numbers. it is suggested to use "the number which express how many times the quantity to be compared is contained by the quantity to be a base is called biyoul." as a definition of biyoul. It is suggested to use "value of bi A : B is A/B" as a definition of value of bi. Halpunri is a variation of halbunri, which is coined by putting hal, pun, and ri together in purpose of using in school mathematics. The tem1 corresponding halpunri is 'bohap', however, in this paper it is suggested to use halpunri after defining it instead of using bohap. In that halpunri is an acclimatized term of bohap, and considered as a biyoul not as a way to indicate biyoul, it is suggested to use "biyoul when the quantity to be a base is considered 10." as a definition of halpunri. It is suggested to see hal, pun, and ri are units for halpunri, and call decimal 0.1 expressing biyoul 1 hal, decimal 0.01 expressing biyoul 1 pun, decimal 0.001 expressing biyoul 1 ri respectively.