• Bulletin of the Korean Mathematical Society
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• v.41 no.3
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• pp.573-587
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• 2004

Disentangling is the essential operation of Feynman's operational calculus for noncommuting operators. Thus formulas which simplify this operation are central to the subject. In a recent paper the procedure for 'extracting a linear factor' has been established in the setting of Feynman's operational calculus for time independent operators $A_1, ... , A_n$ and associated probability measures ${\mu}_1,..., {\mu}_n$. While the setting just described is natural in many circumstances, it is not natural for evolution problems. There the measures should not be restricted to probability measures and it is worthwhile to allow the operators to depend on time. The main purpose for this paper is to extend the procedure for extracting a linear factor to this latter setting. We should mention that Feynman's primary motivation for developing an operational calculus for noncommuting operators came from a desire to describe the evolution of certain quantum systems.m systems.

• Korean Journal of Human Ecology
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• v.21 no.4
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• pp.629-647
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• 2012

This study explored what Korean college students, especially preservice teacher in early childhood education, experienced and how they constructed the meanings of experiences about their subject- matter course (early childhood mathematics education) taught in English. One cohort- 20 senior students- majoring in early childhood education in a 4-year university was participated in this study. Using action research method and narrative research method, data were analyzed. The findings were as follows: 1) preservice teacher experienced some difficulties to construrct professional knowledge through English. 2) They challenged to overcome these difficulties through active participation. 3) They got supports from instructor and peer group. 4) They accomplished the course with self-satisfaction. 5) They experienced the conflicts between social requirements and personal needs.

• Journal of the Korean Mathematical Society
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• v.53 no.1
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• pp.27-43
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• 2016

This paper deals with a degenerate parabolic system with coupled nonlinear localized sources subject to weighted nonlocal Dirichlet boundary conditions. We obtain the conditions for global and blow-up solutions. It is interesting to observe that the weight functions for the nonlocal Dirichlet boundary conditions play substantial roles in determining not only whether the solutions are global or blow-up, but also whether the blowing up occurs for any positive initial data or just for large ones. Moreover, we establish the precise blow-up rate.

• Journal of Acupuncture Research
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• v.20 no.2
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• pp.1-10
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• 2003

Objective : It is limited to verify existence and a part of characteristic of MS(Meridian system) in modern MS hypothesis. Because it is that an object of scientific approach is to prove a structure of MS. Then according to DMMS, we will research on a subject of MSs rules. This is a paper on the investigation of DMMS in aspects of propriety and supplement. Results : DMMS is composed of organizational anatomy system, MS, signal system. This means that the contents of classic MS theory divide into three dimensions. It includes classic MS theory and explains modern MS hypothesis with DMMS. But is has two problems that one is the difference between the right side and the left in the same meridian and the other is a lack of dynamic idea(動態觀念). After apply this ti analysis system, it will be reasonable to DMMS. It indicates to use various ways of a science, especially, mathematics, system theory, information theory, control theory to supplement the DMMS. Conclusions : Although the scientific study of MS is stagnant, the approach of this DMMS will provide us with a new result of MS.

• Research in Mathematical Education
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• v.8 no.2
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• pp.81-93
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• 2004

This study investigated three preservice teachers' mathematical problem solving among hand-in-write-ups and final projects for each subject. All participants' activities and computer explorations were observed and video taped. If it was possible, an open-ended individual interview was performed before, during, and after each exploration. The method of data collection was observation, interviewing, field notes, students' written assignments, computer works, and audio and videotapes of preservice teachers' mathematical problem solving activities. At the beginning of the mathematical problem solving activities, all participants did not have strong procedural and conceptual knowledge of the graph, making a model by using data, and general concept of a sine function, but they built strong procedural and conceptual knowledge and connected them appropriately through mathematical problem solving activities by using the computer technology.

• Journal of Engineering Education Research
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• v.18 no.6
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• pp.38-45
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• 2015

This study aims to conduct a case study of the Science, Technology, Engineering, Arts, and Mathematics (STEAM) outreach program development and their application. This program was operated by 184 middle and high school students at C University on October 2014. The major results of these studies were as follows: First, The theme of the outreach program consisted of four engineering areas, aerospace engineering, chemical engineering, architectural engineering, and mechatronics (robot) engineering; moreover, the materials for the students' workbook, the guidebook for teachers, and the program operation manual for staffs in a university were developed by working with four authors and ten subject matter experts. Second, the satisfaction level with the contents and activities was ranged from 4.24-4.31 out of 5 points. Third, the vitalizing activation plan was discussed for the sustainable development and operation of the STEAM outreach program.

• Journal of Korean Society for Quality Management
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• v.24 no.3
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• pp.31-36
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• 1996

A Markovian stochastic model for a system subject to random shocks is considered. Each shock arriving according to a Poisson process decreases the state of the system by a random amount. A repairman arrives at the system periodically for inspection and repairs the system only if the state is below a threshold. Costs are assigned to each inspection of the repairman, to each repair, and to the system being in bad states below the threshold. The expected long run average cost is obtained and compared with that of the random inspection introduced by Lee and Lee(1994).

• Journal of the Korean Statistical Society
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• v.24 no.2
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• pp.471-479
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• 1995

A random shock model for a linearly deteriorating system is introduced. The system deteriorating linearly with time is subject to random shocks which arrive according to a Poisson process and decrease the state of the system by a random amount. The system is repaired by a repairmen arriving according to another Poisson process if the state when he arrives is below a threshold. Explicit expressions are deduced for the characteristic function of the distribution function of X(t), the state of the system at time t, and for the distribution function of X(t) if X(t) is over the threshold. The stationary case is briefly discussed.

• Communications for Statistical Applications and Methods
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• v.4 no.3
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• pp.637-644
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• 1997

Sometimes, the first principal component may come logically from the established knowledge and premises. For example, for the high school students' test scores of Korean, English, Mathematics, Social Study, and Science, it is natural to define the first principal component as the average of all subject scores. In such cases, we need to respect both the background knowledge and the data exploration. The aim of this study is to find the remaining components in principal component analysis of multivariate data when the first principal component is defined a priori by the researcher. Moreover, we study related matrix decomposition and their application to the graphical display.

• The Mathematical Education
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• v.55 no.1
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• pp.91-106
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• 2016

The aim of this study was to analyze characteristics of teachers' knowledge about reductio ad absurdum. In order to achieve the aim, this study conducted didactical analysis about reductio ad absurdum through examining previous researches and developed a questionnaire with reference to the results of the analysis. The questionnaire was given to 34 high school teachers and qualitative methods were used to analyze the data obtained from the written responses by the participants. This study also elaborated the framework descriptors for interpreting the teachers' responses in the light of the didactical analysis and the data was elucidated in terms of this framework. The specific features of teachers' knowledge about reductio ad absurdum were categorized into five types as a result. This study raised several implications for teachers' professional development for effective mathematics instruction related to reductio ad absurdum.