• Title/Summary/Keyword: multiplication concept

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Examining how elementary students understand fractions and operations (초등학생의 분수와 분수 연산에 대한 이해 양상)

  • Park, HyunJae;Kim, Gooyeon
    • The Mathematical Education
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    • v.57 no.4
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    • pp.453-475
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    • 2018
  • This study examines how elementary students understand fractions with operations conceptually and how they perform procedures in the division of fractions. We attempted to look into students' understanding about fractions with divisions in regard to mathematical proficiency suggested by National Research Council (2001). Mathematical proficiency is identified as an intertwined and interconnected composition of 5 strands- conceptual understanding, procedural fluency, strategic competence, adaptive reasoning, and productive disposition. We developed an instrument to identify students' understanding of fractions with multiplication and division and conducted the survey in which 149 6th-graders participated. The findings from the data analysis suggested that overall, the 6th-graders seemed not to understand fractions conceptually; in particular, their understanding is limited to a particular model of part-whole fraction. The students showed a tendency to use memorized procedure-invert and multiply in a given problem without connecting the procedure to the concept of the division of fractions. The findings also proposed that on a given problem-solving task that suggested a pathway in order for the students to apply or follow the procedures in a new situation, they performed the computation very fluently when dividing two fractions by multiplying by a reciprocal. In doing so, however, they appeared to unable to connect the procedures with the concepts of fractions with division.

Study on Applicability of Nonproportional Model for Teaching Second Graders the Number Concept (초등학교 2학년 수 개념 지도를 위한 비비례모델의 적용 가능성 탐색)

  • Kang, Teaseok;Lim, Miin;Chang, Hyewon
    • Journal of Elementary Mathematics Education in Korea
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    • v.19 no.3
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    • pp.305-321
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    • 2015
  • This study started with wondering whether the nonproportional model used in unit assessment for 2nd graders is appropriate or not for them. This study aims to explore the applicability of the nonproportional model to 2nd graders when they learn about numbers. To achieve this goal, we analyzed elementary mathematics textbooks, applied two kinds of tests to 2nd graders who have learned three-digit numbers by using the proportional model, and investigated their cognitive characteristics by interview. The results show that using the nonproportional model in the initial stages of 2nd grade can cause some didactical problems. Firstly, the nonproportional models were presented only in unit assessment without any learning activity with them in the 2nd grade textbook. Secondly, the size of each nonproportional model wasn't written on itself when it was presented. Thirdly, it was the most difficult type of nonproportional models that was introduced in the initial stages related to the nonproportional models. Fourthly, 2nd graders tend to have a great difficulty understanding the relationship of nonproportional models and to recognize the nonproportional model on the basis of the concept of place value. Finally, the question about the relationship between nonproportional models sticks to the context of multiplication, without considering the context of addition which is familiar to the students.

Development of Bayes' rule education tool with Excel Macro (엑셀 매크로기능을 이용한 베이즈 정리 교육도구 개발)

  • Choi, Hyun-Seok;Ha, Jeong-Cheol
    • Journal of the Korean Data and Information Science Society
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    • v.23 no.5
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    • pp.905-912
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    • 2012
  • We are dealing with the Bayes' rule education tool with Excel Macro and its usage example. When an event occurs, we are interested in whether it does under certain conditions or not. In this case, we use the Bayes' rule to calculate the probability. Bayes' rule is very useful in making decision based on newly obtained statistical information. We introduce an efficient self-teaching educational tool developed to help the learners understand the Bayes' rule through intermediate steps and descriptions. The concept and examples of intermediate steps such as conditional probability, multiplication rule, law of total probability, prior probability and posterior probability could be acquired through step-by-step learning. All the processes leading to result are given with diagrams and detailed descriptions. By just clicking the execution button, users could get the results in one screen.

The formativeness of Maximalism expressed in the modern women's collection - Focusing on the women's collection from 2011 to 2016 - (현대 여성복 컬렉션에 표현된 맥시멀리즘의 조형성에 관한 연구 - 2011년 ~ 2016년 여성복 컬렉션을 중심으로 -)

  • Kim, Kyung-Hee
    • Journal of the Korea Fashion and Costume Design Association
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    • v.20 no.2
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    • pp.101-115
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    • 2018
  • The purpose of this study is to contribute to the development of the women's fashion field with the goal of creating creative and experimental fashion styles through the categorization of cases of women's fashion design expressed with Maximalism, a type of expression used in modern fashion, as well as analyzing and examining the formativeness of this style. Qualitative research was conducted through a literature review and design case analysis. The scope of this research was from 2011 S/S to 2016 F/W, and the regional scope included the women's collections from Paris, Milano, London and New York. The results acquired are as follows. Initially, exaggeration was expressed through excessively exaggerating the overall silhouette of clothing or exaggeratedly distorting certain parts of the overall silhouette. Secondly, decoration was expressed through the use of the same colors and materials and the addition of excessive details and trimmings to express an exaggerated style of clothing as well as to express a luxurious and handcrafted style of clothing. Thirdly, fusion was expressed through integrating multiple items from different cultures, deconstruction, which destroys the concept of gender and use of clothing, and fashion style that transcends time and space. Fourthly, non-structurality was expressed through differentiating multiple weight feelings applied to the left/right sides of clothing or expressing a structural designs that is asymmetrical to the upper/lower/left/right directions to create a silhouette that displays a creative avant-garde style. As examined above, it was found that the maximalism expressed in fashion after 2011 created new images and expressed maximized emotional orientations through the exaggerated use of multiple silhouettes and decorations or through the integration of colors, patterns, ages and images. Through this process, maximalism is expected to not only provide an infinite possibility to the modern fashion that pursues diversification and multiplication, but also serve as an example that represents diversified post-modernism fashion trends in the future.

A Study on Post-formal Spatial Expression in 21 st Century Fashion Design (21세기 패션디자인에 나타난 탈정형적 공간 표현에 관한 연구)

  • Yang, Hee-Young;Kim, So-Young
    • Journal of the Korean Society of Costume
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    • v.58 no.8
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    • pp.91-105
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    • 2008
  • Spatial multiplication phenomenon, expressed through de-constructive trend since the late of 20C, have got changed existing fixed and dis-variable space to smooth, fluid, and changeable space. Ex-form and fluidity of new spatial paradigm have been focused through lots of scientific theories studied between digital thought and indeterminacy and rankless nature phenomena. In 21C fashion, indeterminate and irregular form and space have been crested continuously, which could not explain simply according as the fluidity theory Different from the space crested for multi-function and multipurpose, this is revealed the characteristics of chaosmos that communizes the order and the disorder, deconstruction and creation. Ex-formal space of fashion have shown the relationship of de-centerizing, de-territorial, and do-structural phenomenon among different fashion elements. This paper intends to understand the concept of ex-form, and study expressive manners of ex-formal space of 21C fashion, and conclusion as follows. 1) Overlap changes single space of fashion to multi-layered space through the repeat system of pleats, origami, and folding. 2) Ex-gravity expressed in deviation of the gravity acting vertical direction, for example, twisting, curve, winding, portion. 3) Morphing is shown the change process from single fixed form to different complex form. 4) Blurring is expressed in re-combination and re-arrangement among elements of fashion. 5) Blob shows hybrid fashion space through the liberal compounding and separation of a lot of different elements.

A Study on Haptic Presentation Methods in the Experience Exhibition Spaces - With Experience Exhibition Space - (전시공간에서의 촉지적(Haptic)연출 방법에 대한 연구 - 체험전시 공간 중심으로 -)

  • Cho, Min-Hwa
    • Korean Institute of Interior Design Journal
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    • v.24 no.6
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    • pp.229-239
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    • 2015
  • The 21st century is a multiplication age and social and cultural phenomena have become diverse and peoples' desires and individuality have become important. Accordingly, the sensibility that reflects human taste is also required in the exhibition space. The exhibitions in this age induce the direct cognition of senses or take interactive forms that contact diverse media and react. The purpose of this research is to define the concept of haptic presentation method in which the audience perceive in the exhibition space by themselves and the visual elements spread into other senses and perceive complexly, and to present the directional nature. To conduct this research, first, this researcher recognized that haptic sensory experiential research by analyzing the roles and transition history of exhibition space is needed for the present age Second, based on philosophical theories, four haptic sensory expression characteristics (medium nature, experiential nature, attractiveness, sensitiveness) were derived by substituting Giles Deleuze's four haptic spatial characteristics (grasping short distance, dispersed gaze, cognition of bodily movement, formation of synesthesia through complex senses) and six formative factors of exhibition space (space, form, size, light, quality of materials, and color). And the effective exhibition presentation methods were analyzed through six cases of experiential exhibition spaces. Accordingly, what matters in the experiential exhibition space is to produce the four characteristics: medium nature, experientiality, attractiveness, and sensitiveness in equilibrium. It is necessary for the designers to reflect it appropriately in producing so that the audience can think and experience by themselves. Accordingly, in this thesis, it could be seen that to produce the haptic production characteristics in the experiential exhibition space in equilibrium is the important factor in the experiential exhibition space. In conclusion, experiences in the exhibition space should be approached with the transcendental haptic presentation method by which even the space of actually unexperienced cognition can be expanded and experienced through the metastasis and tension of various senses. Also, researches on such senses should be developed continuously, and this researcher expects that this will become a stimulant to present a new directivity.

Application of TULIP/STREAM code in 2-D fast reactor core high-fidelity neutronic analysis

  • Du, Xianan;Choe, Jiwon;Choi, Sooyoung;Lee, Woonghee;Cherezov, Alexey;Lim, Jaeyong;Lee, Minjae;Lee, Deokjung
    • Nuclear Engineering and Technology
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    • v.51 no.8
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    • pp.1871-1885
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    • 2019
  • The deterministic MOC code STREAM of the Computational Reactor Physics and Experiment (CORE) laboratory of Ulsan National Institute of Science and Technology (UNIST), was initially designed for the calculation of pressurized water reactor two- and three-dimensional assemblies and cores. Since fast reactors play an important role in the generation-IV concept, it was decided that the code should be upgraded for the analysis of fast neutron spectrum reactors. This paper presents a coupled code - TULIP/STREAM, developed for the fast reactor assembly and core calculations. The TULIP code produces self-shielded multi-group cross-sections using a one-dimensional cylindrical model. The generated cross-section library is used in the STREAM code which solves eigenvalue problems for a two-dimensional assembly and a multi-assembly whole reactor core. Multiplication factors and steady-state power distributions were compared with the reference solutions obtained by the continuous energy Monte-Carlo code MCS. With the developed code, a sensitivity study of the number of energy groups, the order of anisotropic PN scattering, and the multi-group cross-section generation model was performed on the keff and power distribution. The 2D core simulation calculations show that the TULIP/STREAM code gives a keff error smaller than 200 pcm and the root mean square errors of the pin-wise power distributions within 2%.

An Analytic Study of Mathematical Problem-Posing Activities for Two-hour Classes - Focusing on 3rd Grade Elementary School Children - (연차시 수업을 통한 수학 문제 만들기 활동 분석 연구 - 초등학교 3학년을 중심으로 -)

  • Shin, Su-Jin;Lim, Mun-Kyu
    • Journal of Elementary Mathematics Education in Korea
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    • v.14 no.1
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    • pp.43-64
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    • 2010
  • This study aimed to foster the learning abilities of mathematics, that is, along with the formation of a sure mathematical concept, extending the powers of doing mathematics, and bringing the creativities for 3rd grade elementary school children. In order to achieve these objects, we have executed mathematical classes for two consecutive hours of 16 times using the teaching model of [Learning contents in textbook]$\rightarrow$[The first problem Posing]$\rightarrow$[Problem solving to childrens' posing some problems]$\rightarrow$[Advanced problem posing] to 3rd grade school children during the first semester of 2009. In this paper, we analyzed problems that are made by children focusing on the four fundamental rules +, -, ${\times}$, $\div$ of arithmetic, with the view points of problem's completion, fluencies, flexibilities, buildings of concept, originalities and using materials. As a result of the comparative analysis of the first problems and advanced problems made by the children, the first problems were revealed to be rather better in of problem's completion and fluencies. And the flexibilities were improved in the division and multiplication classes carried on. Setting up the experimental and comparative class, we compared to the scholastic achievement of two classes for the beginning and end in the first semester. In the result, the former was improved in the scholastic achievement more than the latter.

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A Historical and Mathematical Analysis on the Radian (라디안 개념의 역사적 분석과 수학적 분석)

  • Yoo, Jaegeun;Lee, Kyeong-Hwa
    • Journal of Educational Research in Mathematics
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    • v.27 no.4
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    • pp.833-855
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    • 2017
  • This study aims to reinvestigate the reason for introducing radian as a new unit to express the size of angles, what is the meaning of radian measures to use arc lengths as angle measures, and why is the domain of trigonometric functions expanded to real numbers for expressing general angles. For this purpose, it was conducted historical, mathematical and applied mathematical analyzes in order to research at multidisciplinary analysis of the radian concept. As a result, the following were revealed. First, radian measure is intrinsic essence in angle measure. The radian is itself, and theoretical absolute unit. The radian makes trigonometric functions as real functions. Second, radians should be aware of invariance through covariance of ratios and proportions in concentric circles. The orthogonality between cosine and sine gives a crucial inevitability to the radian. It should be aware that radian is the simplest standards for measuring the length of arcs by the length of radius. It can find the connection with sexadecimal method using the division strategy. Third, I revealed the necessity by distinction between angle and angle measure. It needs justification for omission of radians and multiplication relationship strategy between arc and radius. The didactical suggestions derived by these can reveal the usefulness and value of the radian concept and can contribute to the substantive teaching of radian measure.

A Folksonomy Ranking Framework: A Semantic Graph-based Approach (폭소노미 사이트를 위한 랭킹 프레임워크 설계: 시맨틱 그래프기반 접근)

  • Park, Hyun-Jung;Rho, Sang-Kyu
    • Asia pacific journal of information systems
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    • v.21 no.2
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    • pp.89-116
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    • 2011
  • In collaborative tagging systems such as Delicious.com and Flickr.com, users assign keywords or tags to their uploaded resources, such as bookmarks and pictures, for their future use or sharing purposes. The collection of resources and tags generated by a user is called a personomy, and the collection of all personomies constitutes the folksonomy. The most significant need of the folksonomy users Is to efficiently find useful resources or experts on specific topics. An excellent ranking algorithm would assign higher ranking to more useful resources or experts. What resources are considered useful In a folksonomic system? Does a standard superior to frequency or freshness exist? The resource recommended by more users with mere expertise should be worthy of attention. This ranking paradigm can be implemented through a graph-based ranking algorithm. Two well-known representatives of such a paradigm are Page Rank by Google and HITS(Hypertext Induced Topic Selection) by Kleinberg. Both Page Rank and HITS assign a higher evaluation score to pages linked to more higher-scored pages. HITS differs from PageRank in that it utilizes two kinds of scores: authority and hub scores. The ranking objects of these pages are limited to Web pages, whereas the ranking objects of a folksonomic system are somewhat heterogeneous(i.e., users, resources, and tags). Therefore, uniform application of the voting notion of PageRank and HITS based on the links to a folksonomy would be unreasonable, In a folksonomic system, each link corresponding to a property can have an opposite direction, depending on whether the property is an active or a passive voice. The current research stems from the Idea that a graph-based ranking algorithm could be applied to the folksonomic system using the concept of mutual Interactions between entitles, rather than the voting notion of PageRank or HITS. The concept of mutual interactions, proposed for ranking the Semantic Web resources, enables the calculation of importance scores of various resources unaffected by link directions. The weights of a property representing the mutual interaction between classes are assigned depending on the relative significance of the property to the resource importance of each class. This class-oriented approach is based on the fact that, in the Semantic Web, there are many heterogeneous classes; thus, applying a different appraisal standard for each class is more reasonable. This is similar to the evaluation method of humans, where different items are assigned specific weights, which are then summed up to determine the weighted average. We can check for missing properties more easily with this approach than with other predicate-oriented approaches. A user of a tagging system usually assigns more than one tags to the same resource, and there can be more than one tags with the same subjectivity and objectivity. In the case that many users assign similar tags to the same resource, grading the users differently depending on the assignment order becomes necessary. This idea comes from the studies in psychology wherein expertise involves the ability to select the most relevant information for achieving a goal. An expert should be someone who not only has a large collection of documents annotated with a particular tag, but also tends to add documents of high quality to his/her collections. Such documents are identified by the number, as well as the expertise, of users who have the same documents in their collections. In other words, there is a relationship of mutual reinforcement between the expertise of a user and the quality of a document. In addition, there is a need to rank entities related more closely to a certain entity. Considering the property of social media that ensures the popularity of a topic is temporary, recent data should have more weight than old data. We propose a comprehensive folksonomy ranking framework in which all these considerations are dealt with and that can be easily customized to each folksonomy site for ranking purposes. To examine the validity of our ranking algorithm and show the mechanism of adjusting property, time, and expertise weights, we first use a dataset designed for analyzing the effect of each ranking factor independently. We then show the ranking results of a real folksonomy site, with the ranking factors combined. Because the ground truth of a given dataset is not known when it comes to ranking, we inject simulated data whose ranking results can be predicted into the real dataset and compare the ranking results of our algorithm with that of a previous HITS-based algorithm. Our semantic ranking algorithm based on the concept of mutual interaction seems to be preferable to the HITS-based algorithm as a flexible folksonomy ranking framework. Some concrete points of difference are as follows. First, with the time concept applied to the property weights, our algorithm shows superior performance in lowering the scores of older data and raising the scores of newer data. Second, applying the time concept to the expertise weights, as well as to the property weights, our algorithm controls the conflicting influence of expertise weights and enhances overall consistency of time-valued ranking. The expertise weights of the previous study can act as an obstacle to the time-valued ranking because the number of followers increases as time goes on. Third, many new properties and classes can be included in our framework. The previous HITS-based algorithm, based on the voting notion, loses ground in the situation where the domain consists of more than two classes, or where other important properties, such as "sent through twitter" or "registered as a friend," are added to the domain. Forth, there is a big difference in the calculation time and memory use between the two kinds of algorithms. While the matrix multiplication of two matrices, has to be executed twice for the previous HITS-based algorithm, this is unnecessary with our algorithm. In our ranking framework, various folksonomy ranking policies can be expressed with the ranking factors combined and our approach can work, even if the folksonomy site is not implemented with Semantic Web languages. Above all, the time weight proposed in this paper will be applicable to various domains, including social media, where time value is considered important.