• Journal of the Korean Mathematical Society
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• v.45 no.3
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• pp.727-740
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• 2008

A ring R is called IFP, due to Bell, if ab=0 implies aRb=0 for $a,b{\in}R$. Huh et al. showed that the IFP condition need not be preserved by polynomial ring extensions. But it is shown that ${\sum}^n_{i=0}$ $E_{ai}E$ is a nonzero nilpotent ideal of E whenever R is an IFP ring and $0{\neq}f{\in}F$ is nilpotent, where E is a polynomial ring over R, F is a polynomial ring over E, and $a_i^{'s}$ are the coefficients of f. we shall use the term near IFP to denote such a ring as having place near at the IFPness. In the present note the structures of IFP rings and near-IFP rings are observed, extending the classes of them. IFP rings are NI (i.e., nilpotent elements form an ideal). It is shown that the near-IFPness and the NIness are distinct each other, and the relations among them and related conditions are examined.

• The Mathematical Education
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• v.56 no.1
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• pp.119-130
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• 2017

The purpose of this study is to explain the long term growth and development of elementary teachers' Professional Learning Communities(PLC) about mathematics implemented on an institutional basis. Especially, it is meaningful to analyze and present the development process and characteristics of PLC, which was started by the basis on the collaboration of a National University of Education and its affiliated elementary school. In this study, PLC activities during three years were analyzed according to the capacities and dimensions of a professional learning community. The developmental capacity of the PLC analyzed in this study can be summarized as follows. In the first year, development of organizational competence in terms of capacity, resources, structure, and system of exchanges was the main factor in personal competence, and the development of individual competence began to share collective learning and practice. In the second year, personal exchanges were active in all the topics of activities, and personal level competence was activated such that more activities of critical knowledge formation were performed on an individual level. On the basis of the development of the individual level formed in the second, individual competence and organizational capacity developed. Factors that have influenced the development of capacities of PLC include: disclosure of activities outside the community, participation in outsiders, provision of procedures to share equal participation and leadership, voluntary and critical participation of teachers, improvement of mathematics teaching methods, sharing themes and visions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.1
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• pp.87-94
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• 1986

Under natural condition, many rivers had shallow and gently curved shape in plane. A two dimensional mathematical model of the flow was a very attractive one. The flow characteristics in bended open channels were analyzed. The mathematical model based on the mass and the momentum equation of the two-dimensional unsteady flow was developed by introducing finite difference method and the double sweep algorithm. For the purpose of the verification of this model, the modeling results were applied to the L.F.M flume and the I.I.H.R flume. The results had a good agreement with the experimental data of the flumes. The results could be more close to the experimental data by controlling Chezy Coefficients in order to reduce the effect of friction around side wall, and be studied the importance of the convective term. The water surface profile, the direction and scale of depth average mean velocity and the path of the thread of maximum velocity in bended open channels could be computed.

• Journal of the Korean School Mathematics Society
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• v.17 no.4
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• pp.629-656
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• 2014

This study developed teaching and learning materials for an integrated education program of probability and genetics in the light of connections between mathematics and biological science. It also analysed characteristics of high school students' mathematical activities which appeared while the students took part in lessons where the developed materials were contributed in order to teach them. To achieve the aim, this study firstly specified five details for the development of the materials based on the results of previous research and extracted contents of probability and genetics which had the possibility of being taught in the integrated education program by examining the text books. After embodying the teaching materials according to the five details and the extracted contents, the researchers implemented 10 lessons by using the materials. This study elaborated some implications for a succeeding integrated education of mathematics and biological science in term of anlaysis results of features from the students' mathematical understanding and attitudes emerging in the lessons.

• The Mathematical Education
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• v.56 no.4
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• pp.387-405
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• 2017

The purpose of this study is to investigate the change of students 'perception and expression about the motion of object following distance function $={x \atop 3}$ and distance function $y=\frac{x^3}{3}+3$ according to the necessity of research on students' perception and expression about integral constant. In this paper, we present the recognition and the expression of the difference of the constant in the relationship between the distance function and the speed function of the students, while examining the process of constructing the speed function and the inverse process of the distance function. This provides implications for the relationship between the derivative and the indefinite integral corresponding to the inverse process. In particular, in a teaching experiment, a constructive activity was performed to analyze the motion of two distance functions, where the student had a difference of the constant term. At this time, the students used the expression 'starting point' for the constants in the distance function, and the motion was interpreted by using the meaning. This can be seen as a unique 'students' mathematics' in the process of analyzing the motion of objects. These scenes, in introducing the notion of the relation between differential and indefinite integral, it is beyond the comprehension of the integral constant as a computational procedure, so that the learner can understand the meaning of the integral constant in relation to the motion of the object. It is expected that it will be a meaningful basic research on the relationship between differential and integral.

• Journal of the Korean School Mathematics Society
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• v.15 no.4
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• pp.719-745
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• 2012

This research is a study on student's understanding fundamental conception of mathematical curriculum, especially in geometry domain. The goal of researching is to analyze student's wrong conception about that domain and get the mathematical teaching method. We developed various questions of descriptive assessment. Then we set up the term, procedure of research for the understanding student's knowledge of geometry. And we figured out the student's understanding extent through analysing questions of descriptive assessment in geometry. In this research, we concluded that most of students are having difficulty with defining the fundamental conception of mathematics, especially in geometry. Almost all the students defined the fundamental conceptions of mathematics obscurely and sometimes even missed indispensable properties. Prior to this study, we couldn't identify this problem. Here are some suggestions. First, take time to reflect on your previous mathematics method. And then compile some well-selected questions of descriptive assessment that tell us more about student's understanding in geometry.

• Communications of Mathematical Education
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• v.23 no.4
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• pp.1043-1058
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• 2009

This study concerns with the effects of group projects performed by the students in college math classes. The study result shows that 61% of the students get more self-confidence and interest in mathematics through working projects. In addition, the result reveals that one of the essential factors for successful college mathematics class is to provide a strong motivation for learning to students. For effective teaching through group projects, this paper suggests that 1) the number of students in the class be 20 or less, 2) the projects group be consisted of two members, 3) the instructor should select proper problems to students' level from extra-textbooks, 4) the problems should be interesting, positive and challenging, 5) each group should take only one problem, 6) the groups be provided with enough references and materials, 7) each student in the group be cared to feel importance and necessity of mathematics and cooperative work, 8) the students should work with math joyfully, 9) the instructor remind the students that we live with mathematics in real life, 10) 2-month be a necessary and appropriate term in working projects.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.26 no.4
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• pp.185-223
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• 2022

The classical equation of Jonathan Homer Lane and Robert Emden, a nonlinear second-order ordinary differential equation, models the isothermal spherical clouded gases under the influence of the mutual attractive interaction between the gases' molecules. In this paper, the Adomian decomposition method (ADM) is presented to obtain highly accurate and reliable analytical solutions of a class of generalised Lane-Emden equations with strong nonlinearities. The nonlinear term f(y(x)) of the proposed problem is given by the integer powers of a continuous real-valued function h(y(x)), that is, f(y(x)) = h^m(y(x)), for integer m ≥ 0, real x > 0. In the end, numerical comparisons are presented between the analytical results obtained using the ADM and numerical solutions using the eighth-order nested second derivative two-step Runge-Kutta method (NSDTSRKM) to illustrate the reliability, accuracy, effectiveness and convenience of the proposed methods. The special cases h(y) = sin y(x), cos y(x); h(y) = sinh y(x), cosh y(x) are considered explicitly using both methods. Interestingly, in each of these methods, a unified result is presented for an integer power of any continuous real-valued function - compared with the case by case computations for the nonlinear functions f(y). The results presented in this paper are a generalisation of several published results. Several examples are given to illustrate the proposed methods. Tables of expansion coefficients of the series solutions of some special Lane-Emden type equations are presented. Comparisons of the two results indicate that both methods are reliably and accurately efficient in solving a class of singular strongly nonlinear ordinary differential equations.

• The Mathematical Education
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• v.61 no.1
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• pp.83-108
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• 2022

This research is a case study in which teachers tried to improve classes through online class analysis and self-evaluation in elementary school mathematics classes using a checklist of class reflection based on fair access, autonomy, initiative, and evaluation areas in the TRU analysis framework of Schoenfeld (2016). As a result, it was confirmed that the teacher's fair participation, student autonomy, initiative, feedback, and evaluation areas improved teaching methods during the short time. Therefore, if you want to improve classes in relatively short period of time, you can see the effect of some improvement only by self-evaluation. However, continuous improvement of teaching methods require the help of a teacher communities including experts or critical colleagues, and a longer-term case study.

• Communications of Mathematical Education
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• v.37 no.1
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• pp.47-64
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• 2023

The current elementary mathematics curriculum does not include intensive quantity. However, other subjects also deal with intensive quantity. In order to find a solution to this problem from a pedagogical point of view, the curriculum of mathematics, science, social studies, and elementary textbooks were compared and analyzed, focusing on intensive quantity. As a result of the analysis, the learning contents of intensive quantity were not explicitly presented or the term was not used in the elementary mathematics curriculum. However, intensive quantity was used as a material of activity and word problems in elementary mathematics textbooks. In science and social studies, it was also found that the learning order and content did not match, such as calculating the intensive quantity. For effective learning, it is necessary to consider presenting intensive quantity in elementary mathematics, and to be careful in the composition of learning order and content.