• 제목/요약/키워드: mathematical objects

검색결과 243건 처리시간 0.025초

APPLICATION OF BENFOR'S EQUATIONS TO THE PROBLEM OF "SEEING THROUGH LAYERS"

  • Krivoshiev, Georgi -P.;Chalucova, Raina-P.;Dahm, Donald-J.
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • 한국근적외분광분석학회 2001년도 NIR-2001
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    • pp.1132-1132
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    • 2001
  • This work is a further development of the method created by G. Krivoshiev in 1996 for elimination of peel interference and prediction of fruit flesh optical density. In this investigation, as it was earlier, the objects are observed as being structured by three successive layer “AlongrightarrowOlongrightarrowB” denoting “peel-flesh-peel”. In the first version of the method the transmittances of the surface layers A and B were measured according to Kubelka-Munk theory by means of their diffuse reflectance. At that the overall transmittance T was approximated in the form of a multiplication approximation being valid for plane-parallel layers of a non-scattering material. In this work this approximation was done away with applying the theory of discontinuum, respectively Benfor's equations. As a result two mathematical models were created for non-destructive prediction of fruit flesh optical density. These models are different from the ones based solely on Kubelka-Munk theory, the destruction being marked by the terms 1n (1 - $R_{A}R_{0}$) and 1n (1 - $R_{A}R_{B}$), where: $R_{A}$ and $R_{B}$ are reflectance values for the surface layers A and B; $R_{0}$ is the average reflectance of the internal layer that could be obtained empirically by means of a preliminary measurement of sufficiently large number of physically peeled fruits of a given species and variety.

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Comparative Analysis of CNN Techniques designed for Rotated Object Classifiation (회전된 객체 분류를 위한 CNN 기법들의 성능 비교 분석)

  • Hee-Il Hahn
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • 제24권1호
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    • pp.181-187
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    • 2024
  • There are two kinds of well-known CNN methods, the group equivariant CNN and the CNN using steerable filters, which have excellent classification performances for randomly rotated objects in image space. This paper describes their mathematical structures and introduces implementation methods. We implement them, including the existing CNN, which have the same number of filters, then compare and analyze their performances by simulating them with the randomly rotated MNIST. According to the experimental results, the steerable CNN, which shows a classification improvement over the others, has a relatively small number of parameters to learn, so performance degradation is relatively small even when the size of the training dataset is reduced.

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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    • 제14권1호
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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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Student Understanding of Scale: From Additive to Multiplicative Reasoning in the Constriction of Scale Representation by Ordering Objects in a Number Line (척도개념의 이해: 수학적 구조 조사로 과학교과에 나오는 물질의 크기를 표현하는 학생들의 이해도 분석)

  • Park, Eun-Jung
    • Journal of The Korean Association For Science Education
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    • 제34권4호
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    • pp.335-347
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    • 2014
  • Size/scale is a central idea in the science curriculum, providing explanations for various phenomena. However, few studies have been conducted to explore student understanding of this concept and to suggest instructional approaches in scientific contexts. In contrast, there have been more studies in mathematics, regarding the use of number lines to relate the nature of numbers to operation and representation of magnitude. In order to better understand variations in student conceptions of size/scale in scientific contexts and explain learning difficulties including alternative conceptions, this study suggests an approach that links mathematics with the analysis of student conceptions of size/scale, i.e. the analysis of mathematical structure and reasoning for a number line. In addition, data ranging from high school to college students facilitate the interpretation of conceptual complexity in terms of mathematical development of a number line. In this sense, findings from this study better explain the following by mathematical reasoning: (1) varied student conceptions, (2) key aspects of each conception, and (3) potential cognitive dimensions interpreting the size/scale concepts. Results of this study help us to understand the troublesomeness of learning size/scale and provide a direction for developing curriculum and instruction for better understanding.

An Epistemological Inquiry on the Development of Statistical Concepts (통계적 개념 발달에 관한 인식론적 고찰)

  • Lee, Young-Ha;Nam, Joo-Hyun
    • The Mathematical Education
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    • 제44권3호
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    • pp.457-475
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    • 2005
  • We have inquired on what the statistical classes of the secondary schools had been aiming to, say the epistermlogical objects. And we now appreciate that the main obstacle to the systematic articulation is the lack of anticipation on what the statistical concepts are. This study focuses on the ingredients of the statistical concepts. Those are to be the ground of the systematic articulation of statistic courses, especially of the one for the school kids. Thus we required that those ingredients must satisfy the followings. i) directly related to the contents of statistics ii) psychologically developing iii) mutually exclusive each other as much as possible iv) exhaustive enough to cover all statistical concepts We examined what and how statisticians had been doing and the various previous views on these. After all we suggest the following three concepts are the core of conceptual developments of statistic, say the concept of distributions, the summarizing ability and the concept of samples. By the concepts of distributions we mean the frequency views on each random categories and that is developing from the count through the probability along ages. Summarizing ability is another important resources to embed his probe with the data set. It is not only viewed as a number but also to be anticipated as one reflecting a random phenomena. Inductive generalization is one of the most hazardous thing. Statistical induction is a scientific way of challenging this and this starts from distinguishing the chance with the inevitable consequences. One's inductive logic grows up along with one's deductive arguments, nevertheless they are different. The concept of samples reflects' one's view on the sample data and the way of compounding one's logic with the data within one's hypothesis. With these three in mind we observed Korean Statistic Curriculum from K to 12. Distributional concepts are dealt with throughout but not sequenced well. The way of summarization has been introduced in the 1 st, 5th, 7th and the 10th grade as a numerical value only. One activity on the concept of sample is given at the 6th grade. And it jumps into the statistical reasoning at the selective courses of ' Mathematics I ' or of ' Probability and Statistics ' in the grades of 11-12. We want to suggest further studies on the developing stages of these three conceptual features so as to obtain a firm basis of successive statistical articulation.

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Multi-Criteria Group Decision Making under Imprecise Preference Judgments : Using Fuzzy Logic with Linguistic Quantifier (불명료한 선호정보 하의 다기준 그룹의사결정 : Linguistic Quantifier를 통한 퍼지논리 활용)

  • Choi, Duke Hyun;Ahn, Byeong Seok;Kim, Soung Hie
    • Journal of Intelligence and Information Systems
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    • 제12권3호
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    • pp.15-32
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    • 2006
  • The increasing complexity of the socio-economic environments makes it less and less possible for single decision-maker to consider all relevant aspects of problem. Therefore, many organizations employ groups in decision making. In this paper, we present a multiperson decision making method using fuzzy logic with linguistic quantifier when each of group members specifies imprecise judgments possibly both on performance evaluations of alternatives with respect to the multiple criteria and on the criteria. Inexact or vague preferences have appeared in the decision making literatures with a view to relaxing the burdens of preference specifications imposed to the decision-makers and thus taking into account the vagueness of human judgments. Allowing for the types of imprecise judgments in the model, however, makes more difficult a clear selection of alternative(s) that a group wants to make. So, further interactions with the decision-makers may proceed to the extent to compensate for the initial comforts of preference specifications. These interactions may not however guarantee the selection of the best alternative to implement. To circumvent this deadlock situation, we present a procedure for obtaining a satisfying solution by the use of linguistic quantifier guided aggregation which implies fuzzy majority. This is an approach to combine a prescriptive decision method via a mathematical programming and a well-established approximate solution method to aggregate multiple objects.

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A Study of Teaching-Learning Method Using Real Objects and Development of Materials for Student Evaluation - Focused on 1st Grade Middle School Students - (구체적 조작물을 활용한 교수-학습과 평가자료 개발에 관한 연구)

  • 고혜정;김승동
    • Journal of the Korean School Mathematics Society
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    • 제5권2호
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    • pp.1-15
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    • 2002
  • The purpose of this study came to start to be helpful in that the teachers in field produced evaluation subject about the mathematics and applied by analyzing the performance capacity for the students about the subject developed through the application of subject about the teaching-learning model that can utilize the learners' learning experience and the development of items that can evaluate it by utilizing various and concrete operational materials as an object of the first year at the middle schools. The concrete purpose of realizing it is as follows. 1. This study is to develop the teaching-learning model centered on activities adequate to utilize various and concrete operational materials. 2. This study is to develop evaluation data for utilizing the concrete operational materials by making construction through the application of developed teaching-learning model as possible. 3. This study is to present standards initiative for reliable and fair marking about the evaluation data and to analyze the students' practice capacity by using it effectively. For accomplishing the purpose of this research, this study is the work-oriented teaching and learning model using learning data that can be easily found around the surroundings and 8 evaluation programs in order that the experience-oriented learning based on circumstances learning among the learning models of constructivism. Also, it is to examine the result after applying that on a basis of 25 students, consisted of only on class in a year, in the first year at the small size of agricultural middle schools. The result of this study from this research is as follows. First, as a result of frequency survey, of response about the developed evaluation data it showed positive response more than 80% of all the items. The atmosphere of self-directed learning was produced because the developed evaluation data could induce activity-based learning naturally by stimulating the students' curiosity and promoting interest. Second, this study executed t-test for the result of questionnaire about the mathematics propensity, and there were significant differences in 19 items among 25 items. It presented that the application of data about the teaching-learning and evaluation directly using concrete operational materials to the constructional learning by level might have desirable affect on the students' mathematical propensity. It came to be a motive that could increase value recognition and interest on the subject of mathematics by investigating a mathematical principle rule and confirming it through activity learning using the concrete operational materials.

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Mathematician Taylor's Linear Perspective Theory and Painter Kirby's Handbook (수학자 테일러의 선 원근법과 화가 커비의 해설서)

  • Cho, Eun-Jung
    • The Journal of Art Theory & Practice
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    • 제7호
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    • pp.165-188
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    • 2009
  • In the development of linear perspective, Brook Taylor's theory has achieved a special position. With his method described in Linear Perspective(1715) and New Principles of Linear Perspective(1719), the subject of linear perspective became a generalized and abstract theory rather than a practical method for painters. He is known to be the first who used the term 'vanishing point'. Although a similar concept has been used form the early stage of Renaissance linear perspective, he developed a new method of British perspective technique of measure points based on the concept of 'vanishing points'. In the 15th and 16th century linear perspective, pictorial space is considered as independent space detached from the outer world. Albertian method of linear perspective is to construct a pavement on the picture in accordance with the centric point where the centric ray of the visual pyramid strikes the picture plane. Comparison to this traditional method, Taylor established the concent of a vanishing point (and a vanishing line), namely, the point (and the line) where a line (and a plane) through the eye point parallel to the considered line (and the plane) meets the picture plane. In the traditional situation like in Albertian method, the picture plane was assumed to be vertical and the center of the picture usually corresponded with the vanishing point. On the other hand, Taylor emphasized the role of vanishing points, and as a result, his method entered the domain of projective geometry rather than Euclidean geometry. For Taylor's theory was highly abstract and difficult to apply for the practitioners, there appeared many perspective treatises based on his theory in England since 1740s. Joshua Kirby's Dr. Brook Taylor's Method of Perspective Made Easy, Both in Theory and Practice(1754) was one of the most popular treatises among these posterior writings. As a well-known painter of the 18th century English society and perspective professor of the St. Martin's Lane Academy, Kirby tried to bridge the gap between the practice of the artists and the mathematical theory of Taylor. Trying to ease the common readers into Taylor's method, Kirby somehow abbreviated and even omitted several crucial parts of Taylor's ideas, especially concerning to the inverse problems of perspective projection. Taylor's theory and Kirby's handbook reveal us that the development of linear perspective in European society entered a transitional phase in the 18th century. In the European tradition, linear perspective means a representational system to indicated the three-dimensional nature of space and the image of objects on the two-dimensional surface, using the central projection method. However, Taylor and following scholars converted linear perspective as a complete mathematical and abstract theory. Such a development was also due to concern and interest of contemporary artists toward new visions of infinite space and kaleidoscopic phenomena of visual perception.

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The Effects of Children's Forest Math Game Activities on Their Understanding of Number and Space Concept (유아의 숲 체험 수학놀이 활동이 수와 공간 개념 이해에 미치는 효과)

  • Kang, Young-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • 제19권11호
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    • pp.473-480
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    • 2018
  • This study is intended to look into the effects of children's forest math game activities on their understanding of number and space concept. To achieve this, an evaluation was carried out to 20 4-year-old children in each group - experimental group and control group - by an evaluation sheet after forest math game activities during a total of 16 sessions 4 times a week for 4 weeks. The findings are as follows. First, children's forest math game activities had an effect on their understanding of number and space concept. Second, the difference between experimental group and control group showed that the experimental group received higher evaluation in the classifying and order finding items than the control group. It was confirmed that classifying and order finding in the forest math game were factors to help children's mathematical problem-understanding abilities. This implies that their forest math game activities have a positive effect on their mathematical problem-understanding abilities. Consequently, active forest math game activities for children are needed to help them understand the concept of number in the process of classifying task objects and solving tasks in order.

터보펌프 공급식 액체 로켓엔진의 시동 과도 해석

  • Park, Soon-Young;Nam, Chang-Ho;Moon, In-Sang;Seol, Woo-Seok
    • Aerospace Engineering and Technology
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    • 제4권2호
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    • pp.142-152
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    • 2005
  • There are two definite objects for developing the startup transient of liquid rocket engine. One is to achieve the repeatability of startup to ensure higher reliability, and the other is to reduce the time of the startup transient. Typically in the initial phase of engine development as we are currently opposing, it is hard to estimate engine startup time due to the lack of experiences. In this work, a startup transient analysis tool was developed with the introduction of the mathematical model for each component of pump-fed liquid rocket engine system. Startup transient was investigated for a 25 ton class gas generator cycle engine to find necessary time for reaching steady state from startup and this enabled to reveal dynamic characteristics of the engine.

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