• 제목/요약/키워드: counting numbers

검색결과 94건 처리시간 0.021초

중학교 수학 수업에서 정수의 사칙계산 지도를 위한 직관적 모델의 역할에 관한 연구 (On the Role of Intuitive Model for Teaching Operations of Integers in the Middle School Mathematics Class)

  • 김익표
    • 한국학교수학회논문집
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    • 제11권1호
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    • pp.97-115
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    • 2008
  • 고등학교 수학 수업에서는 실수 전체의 집합에서 뺄셈은 빼는 수의 덧셈의 역원을 더하고 나눗셈은 나누는 수의 곱셈의 역원을 곱하는 형식적인 관점으로 다룬다. 본 논문에서는 정수의 사칙계산 지도에 있어서 중학교 수학 수업에서 사용되는 직관적 모델(수직선 모델, 셈돌 모델)과 고등학교 수학 수업에서 제시되는 형식적 관점과의 연계에 대하여 논의하고자 한다. 직관적 모델을 이용하여 정수의 뺄셈을 덧셈을 이용하여 나타내는 방법의 의미를 재조명하고 이를 바탕으로 (음수)${\times}$(음수)가 양수임을 지도하는 새로운 방안을 제안하고자 한다. 직관적 모델의 일관성 있는 활용에 바탕을 두고 Treffers(1986)와 Freudenthal(1991)이 제안한 수평적 수학화(horizontal mathematization)의 과정을 통하여 정수의 사칙계산을 지도하는 이 방법은 중학교와 고등학교에서 정수의 사칙계산 수업에 참여하는 교사와 학생들 모두에게 나타날 수 있는 단절(박임숙, 2001)을 제거할 수 있는 방안이 될 것이다. 또 이것은 중 고등학교에서 다루는 수 체계들이 대학과정 대수학에서 다루는 추상적인 수 체계(group, ring, field)와 계통성을 가진 하나의 개념구조를 형성한다는 사실을 학생들이 인지할 수 있는 밑바탕이 될 것이다.

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우리나라의 하구는 몇 개인가? (How many estuaries are there in Korea?)

  • 조홍연;조범준;김한나
    • 한국해안해양공학회지
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    • 제19권3호
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    • pp.274-294
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    • 2007
  • 우리나라 하구의 개수를 파악하기 위해서는 하천의 개수를 파악하는 방법으로 접근할 필요가 있다. 하천의 개수를 파악하는 방법은 하천법에서 규정되어 있는 하천분류기준(국가하천, 지방1급하천, 지방2급하천)을 따르는 것이 바람직할 것으로 사료된다. 우리나라의 국가하천 규모의 하구는 한강(+임진강+례성강), 안성천, 삽교천, 금강, 만경강, 동진강, 영산강, 탐진강, 섬진강, 가화천, 낙동강(+서낙동강), 태화강, 형산강 하구로 총13개(서낙동강, 임진강 분리하는 경우 총15개)이며, 지방1급하천 규모의 하구는 영덕오십천, 삼척오십천, 강릉남대천, 양양남대천 하구로 총4개이다. 반면, 우리나라 연안의 지방2급하천 규모의 하구는 모두 444개(제주도 포함)로 파악되었다. 행정구역별로는 전라남도 108개, 경상남도 94개, 충청남도 52개, 제주도 35개 순으로 파악되었으며, 서해안을 포함한 인위적인 구조물 및 연안개발사업으로 인하여 하구의 기능을 상실한 것으로 판단되는 하구(과거의 하구)가 포함되어 있으며, 하천의 종점이 조정(변경)되는 경우도 발생하기 때문에 분류하는 사람에 따라 다소 차이가 발생 할 수 도 있을 것으로 판단된다.

상주 및 인근지역 단체급식소의 다량조리 실태 연구 -식단분석 및 다량조리 실태- (A Study on the Quantity Food Production Practices of Foodservice in Sangju and Near-by Region)

  • 박모라;김귀영;박필숙;강우원
    • 동아시아식생활학회지
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    • 제8권1호
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    • pp.36-50
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    • 1998
  • The purpose of this study was to investigate quantity food production practices in foodservices by analysing the menus of April, 1996, The questionnaire was developed and responded to by 96 dietitians in Sangju, Munkyung, Gumee, Kimchun, and Andong during November, 1996. The survey was performed by simple random samplings. The results were as follosw; 1. Hospitals and industry served food for thirty days and schools for twenty days. Kimchi was a select-menu for hospitals and one side dish for industry and schools. The type of menu was a single use menu which consisted of cooked rice, soups and three side dishes. 2. The most frequently used ingredients were green onions, rice, carrots, onions, Korean radish roots, pork, eggs, glutinous rice, and milk. Kimchis were served most frequently in all food services and cooked rices and soups were next. 3. The age of most of the respondents was 26 to 30.54.2% of subjects were juniou college graduates and 77.1% were single. Fifty seven point three percent of the dietitians lived with family relatives, or friends. 87.5% of the dietitians had been working for 1 to 5 years. 4. Most foodservices were self-operated. The number of meals served was determined by meal coupon counting in hospitals(37.5%), meal board counting in industry(29.2%), and attendance card counting in schools(41.1%) The cost of sales per meal was approximately 2,450 won in hospitals and was approximately 1,100 won in industry and schools. The average number of days per menucycle was 7.4 in hospitals. 10.3 in industry and 25.5 in schools. Hospitals, industry, and schools held about 118, 265 and 263 recipes respectively. The average number of dietitians was 2.6 in hospitals and 1.0 in industry and schools. Except for the number of recipes, the general practices of foodservices were significantly different(P<0.05). 5. In the general quantity food production, food and seasonings measuring was hardly done. the percentage of foodservices using chemical seasonings was higher in hospitals and industry than in schools. the most important concern was taste, Registered cooks were employed in 75% of schools but only 50.0% in hospitals and 20.8% in industry. Most of the dietitians respinded that their cooks skill was not bad. The education of unregistered cooks was performen once or two times a month in hospitals and industry, and in schools performed everyday. The problem when educating cooks was the lack of cooking skill of the dietitians in schools, and the lack of time in hospitals, and the negative attitude toward education in industry. The method for improving cooking in all foodservices was OJT, or the extension of education facilities and the development and dissemination of standard recipes. The frequency of throwing away leftovers was higher in hospitals. But in industry, the frequency of saving leftovers was higher. 6. Though all foodservices have standard recipes, the number that used them was low, Another problem is that standard recipes resulted in leftovers. The inconveniences of using standard recipes were the difficulty of applying standard recipes to various numbers of customers the complication of use, or facility insufficiency.

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학령 전 아이들의 사칙연산 문장제 해결 능력과 방법 분석 (An Analysis on the Competence and the Methods of Problem Solving of Children at the Before of School Age in Four Operations Word Problems)

  • 이대현
    • 한국학교수학회논문집
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    • 제13권3호
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    • pp.381-395
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    • 2010
  • 학령 전 아이들은 형식적인 교육을 받지 않고서도 일상적인 경험이나 비형식적인 방법으로 수를 익히고, 계산을 한다. 따라서 학령 전 아이들의 수학적 능력에 대한 이해는 유치원 교육과 초등학교 저학년의 수학 학습 지도에 시사점을 줄 수 있다는 변에서 중요하다. 본 연구에서는 학령 전인 만 5세의 아이들이 사칙연산 문장제의 의미론적 측면의 문제 유형에 어느 정도의 해결 능력과 방법을 보이는가를 조사하였다. 연구 결과, 만 5세의 학령 전 아이들은 5보다 크고 10보다 작은 수로 구성된 사칙연산 문장제에 대하여 구체물을 이용한 비형식적 연산의 수행과 정신적 암산을 수행하는 방법을 통하여 문제를 해결할 수 있는 능력을 가지고 있음을 알 수 있었다. 이것은 학령 전 아이들의 수학적 경험을 위한 교육과정이나 프로그램을 체계적으로 구성하여 제시할 필요성을 제기한다.

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수학 학습부진아 예방을 위한 가정학습 효율화 방안 연구 (A Study on a Home Teaching Method to Prevent Slow Learner in Elementary School Mathematics)

  • 이영하;박희연
    • 한국수학교육학회지시리즈A:수학교육
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    • 제40권2호
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    • pp.195-215
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    • 2001
  • The purpose of this paper is to present a specific set of home teaching methods in hopes to prevent slow learner of the elementary mathematics. This paper deals with the number and operations, one of five topics in the elementary mathematics A survey of two hundred elementary school teachers was made to see the teacher's opinions of the role of home studying and to concretize the contents of the research topics. There were asked which is the most essential contents for the concrete loaming and which is the most difficult monad that might cause slow leaner. And those were found to be; counting, and arithmetic operations(addition and subtraction) of one or two-digit numbers and multiplication and their concepts representations and operations(addition and subtraction) of fractions. The home teaching methods are based on the situated learning about problem solving in real life situations and on the active teaming which induces children's participation in the process of teaching and learning. Those activities in teaching each contents are designed to deal with real objects and situations. Most teaching methods are presented in the order of school curriculum. To teach the concepts of numbers and the place value, useful activities using manipulative materials (Base ten blocks, Unifix, etc.) or real objects are also proposed. Natural number's operations such as addition, subtraction and multiplication are subdivided into small steps depending upon current curriculum, then for understanding of operational meaning and generalization, games and activities related to the calculation of changes are suggested. For fractions, this paper suggest 10 learning steps, say equivalent partition, fractional pattern, fractional size, relationship between the mixed fractions and the improper fraction, identifying fractions on the number line, 1 as a unit, discrete view point of fractions, comparison of fractional sizes, addition and subtraction, quantitative concepts. This research basically centers on the informal activities of kids under the real-life situation because such experiences are believed to be useful to prevent slow learner. All activities and learnings in this paper assume children's active participation and we believe that such active and informal learning would be more effective for learning transfer and generalization.

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눈깜빡임 패턴에 기반한 십진 패스워드 입력 방법 (An Input Method for Decimal Password Based on Eyeblink Patterns)

  • 이승호
    • 한국정보통신학회논문지
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    • 제26권5호
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    • pp.656-661
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    • 2022
  • 네자리 디지털 숫자를 입력하는 패스워드 방식이 신용카드 승인용 비밀번호, 디지털 도어락 개폐 비밀번호 등으로 널리 활용되고 있다. 하지만 이 패스워드 방식에서는 네자리의 숫자가 손가락 지문이나 버튼의 마모 등으로 쉽게 추측될 수 있어서 보안 상 안전하지 않다. 또한 장기화되는 코로나19 팬데믹으로 인해 인증에서 접촉 방식보다는 비접촉 방식이 점점 더 선호되고 있다. 본 논문에서는 카메라로 촬영된 얼굴의 눈깜빡임 패턴 분석에 기반한 패스워드 생성 방법을 제안한다. 제안 방법은 0부터 9까지(또는 9부터 0까지) 카운팅 되는 신호에 맞춰 행해진 일련의 눈깜빡임 동작을 분석하고 코드화하여 십진수 네자리를 생성한다. 제안 방법은 패스워드 노출 위험이 유발되는 키패드 입력이나 과장된 행동을 필요로 하지 않는다는 장점이 있다.

Simple Method for a Cell Count of the Colonial Cyanobacterium, Microcystis sp.

  • Joung, Seung-Hyun;Kim, Choong-Jae;Ahn, Chi-Yong;Jang, Kam-Yong;Boo, Sung-Min;Oh, Hee-Mock
    • Journal of Microbiology
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    • 제44권5호
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    • pp.562-565
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    • 2006
  • The cell counting of colonial Microcystis spp. is a rather difficult and error-prone proposition, as this genus forms irregularly-shaped and irregularly-sized colonies, which are packed with cells. Thus, in order to facilitate a cell count, four methods of dividing the colonies into single cells were compared, including vortexing, sonication, $TiO_2$ treatment, and boiling. As a result, the boiling method was determined to generate the greatest number of single cells from a colony, and all colonies were found to have divided completely after only 6 min of treatment. Furthermore, no significant cell destruction, which might alter the actual cell density, was detected in conjunction with the boiling method (P=0.158). In order to compute the cell number more simply, the relationship between the colony size and the cell number was determined, via the boiling method. The colony volume, rather than the area or diameter was correlated more closely with the cell number ($r^2=0.727$), thereby suggesting that the cell numbers of colonial Microcystis sp. can also be estimated effectively from their volumes.

Gas 분사장치(噴射裝置)에 의(依)한 혐기성배양법(嫌氣性培養法)을 이용(利用)한 소 간농양(肝膿瘍)의 세균학적(細菌學的) 연구(硏究) (Bacteriological Studies on Liver Abscess of Cattle by the Gas Jet Anaerobic Culture Method)

  • 마점술
    • 대한미생물학회지
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    • 제11권1호
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    • pp.79-85
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    • 1976
  • There are many of anaerobic culture methods and equipments for isolation and cultivation of anaerabic bacteria, but most of these methods are used without pre-reduced media. Gas-jet method is a recommend. able method for the culture of anaerobes, resently developed. Bacteriological studies were experimented of liver abscess of cattle by the use of gas. jet method. The results were summarised as follows; 1. Gas-jet method for anaerobic culture are expedient for the making of pre-reduced media, maintaining of oxygen free condition in the culture tube, picking of bacteria from colony and colony counting etc. 2. A 121 strains of facultative anaerobic and anaerobic bacteria were isolated from liver abscess of 27 head of cattle, and the isolated anaerobic bacteria were as follows. Peptostreptococcus spp. 7 strains Acid aminococcus fermentans 1 Veillonella spp. 1 Bacterioides spp. 6 Bifidobacterium spp. 4 Arachinia propionica 2 Lactobacillus spp. 4 Propionibacterium acnes 1 3. Liver abscess were infected with many of bacteria, about $10^3-10^9$ numbers per gram of abcessed tissue. Almost of abscess were mixed infection of various bacterial species rather than simple species.

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Early Selection of Double Flowers Based on Cotyledon Shape in Cut Stock (Matthiola incana L.) Flowers

  • Irani, Sepideh Famil;Arab, Mostafa
    • 원예과학기술지
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    • 제35권2호
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    • pp.265-275
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    • 2017
  • Selection of double-flowered plants at the seedling stage is one of the main purposes of stock breeding programs. Eight stock cultivars of Matthiola incana L. named 'Nobel', 'Cinderella', 'Pacific', 'Avalanche', 'Midblue', 'Lavender', 'Goddess' and 'Esfahan', with different percentage of double-flowered plants were used for examining the relationship with three morphological types of cotyledons. The results of a chi-square test indicated that in heart-shaped (HC) and cup-shaped cotyledon (CC) populations, the number of plants with double flowers was much more than that of single flowers and CC seedlings rarely produced single flowers. Therefore, increasing the number of CC seedlings can improve the percentage of double flowers. The highest and lowest numbers of CC seedling were observed in high double and single flower cultivars, respectively. Single flower cultivars showed the maximum count of dumbbell-shaped cotyledons. Chromosome pairing of these cultivars was evaluated using the squash technique. Aneuploid cells were found in 'Nobel' and 'Goddess' cultivars, which showed the highest percentage of CC seedling. Based on morphological measurements, the highest value of inflorescence size was observed in the seedlings with cup-shaped cotyledons.

葯培養 由來 녹색꽃양배추(Broccoli)의 幼植物 馴化 및 培數性 調査 (Polyploidy and Acclimatization Rate of Broccoli Plane Derived from Anther Culture)

  • 이광식;박재복;안춘희;윤여중
    • 식물조직배양학회지
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    • 제25권5호
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    • pp.315-318
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    • 1998
  • 약배양 유래 녹색꽃양배추의 유식물 순화율 및 배수성을 조사하였다. 7가지 공시 품종중 순화율에 있어 Marathon은 80.8∼100%, Landmark는 79.2∼100%, Mariner는 71.4∼79.2%로 나타나 평균 순화율은 83.6%∼86.1% 이였다. 소포자 배에서 생성된 식물체의 배수성은 공변세포내 엽연체수 측정으로도 가능했으며, 또한 배수성의 조기측정을 위해 I-KI용액을 사용하여 엽록체의 즉시염색 관찰이 가능했다. 관찰된 평균 엽녹체수는 반수체가 8.5, 2배체는 13.5, 그리고 4배체는 18.5개로 나타 났으며 이를 기초로 분류한 재분화개체의 배수성은 반수체 47.1∼51.3%, 2배체 47.9∼51.7%, 4배체 0.8∼l.2% 로서 반수체와 2배체가 각각 반씩이고 4배체가 극히 적게 분포하며 인위적인 염색체 배가 없이도 상당수의 자연 배가된 2배체를 얻을 수 있었다.

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