• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.379-392
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• 1996

A mathematic model was developed for the simulation of sideways overturning of agricultural tractors on slopes. The overturning motion was described as a combination of the rotational motions with respect to the first and second tipping axes using the principle of conservation of angular mementum. A stability criterion was also established in terms of angular acceleration of tractor about the second tipping axis. Verification of the proposed model was provided by comparing the stability boundaries predicted by computer simulation with those observed experimentally for an equivalent 1/6 scaled mode tractor. A good agreement was shown between the simulation and experimental results.

• Journal of Biomedical Engineering Research
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• v.11 no.1
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• pp.171-178
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• 1990

This paper describes a software algorithm for automatic diagnosis of arrhythmia using the criteria of Minnesota code manual. This algorithm provides more accurate and more objective information to medical doctor by standardizing the criteria of diagnosis of arrhythmia. Because this algorithm doesn't need complicated mathematic processing, it carries out the real-time automatic diagnosis that is very important in clinic. The Decision-Table technology suggests the proper results for the given conditions. So it can express clearly the complicated medical problems those are not solved by the mathematical methods. The Decision-Tables have very simple structure. Therefore, it is very easy to correct or expand the system by adding or correcting some rules.

• Education of Primary School Mathematics
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• v.2 no.1
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• pp.27-35
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• 1998

The purpose of this research is to analyze the problem of mathematic education of Korean Kindergarten, to search for the solution of the problem in korean Kindergarten. In particular, materials are mostly made and used by the teachers themselves, consuming too much time. Mathematics education materials available in Kindergartens were found to be insufficient. The reasons were the lack of effort by teachers to develop new materials as well as the lack of marketed materials.

• School Mathematics
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• v.4 no.4
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• pp.539-554
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• 2002

Mathematics is constructed by many signs, and learning mathematics involves the understanding and uses of them. This study reflects mathematical signs and their meanings, and considers how they can be introduced in learning. For these, we first investigated epistemological positions as Piaget, Vygotsky, anthropology, and interactionism. And we investigated semiotic models that Saussure and Peirce built each. Among these we adopted Peirce' triadic model that is consisted of interpretant, object (referent), and represen tamen(sign). In mathematic learning process, representations are transformed by translations and meanings are growed to the representation of another sign. And the meaning of sign grows by learner's interpretation. In terms of theoretical grounds, we settled that the understanding of mathematical signs involved the understanding of their representations and their meanings. On the foundation of above contents, we searched how we introduced signs to students and there were methods that approached to students representationally or inquiringly.

• East Asian mathematical journal
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• v.36 no.2
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• pp.203-227
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• 2020

This study is observed in this paper that how the mathematical beliefs of elementary pre-service teachers are reflected in planning and implementing actual mathematics classes. The subjects for this study are senior students at the university of education. After examining their mathematical beliefs and analyzing their actual mathematics classes in a teaching practicum, the following conclusions are drawn. First, the mathematical beliefs of elementary pre-service teachers have generally shown in a similar tendency. The beliefs formed by the students' experience and the beliefs established in the course of preparing to become teachers have coexisted. Second, the teachers' belief in learning mathematics and the teaching practices are largely inconsistent. Third, when elementary pre-service teachers plan and implement their mathematic classes, they are influenced by their guidance teachers and students as well as their own mathematical beliefs.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.326-328
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• 2005

High speed rotational arc sensing is an important method to detect the torch deviation during automatic seam tracking of arc welding. In this paper, a mathematic model of high speed rotational arc sensing is analyzed. The simulation results are consistent with the experimental results. The current waveforms at the beginning of the welding are different from those at middle of the welding because of the formation of the weld bead profile. The signal patterns for seam tracking and end-point detection are proposed. A phase shift between the rotation and the current variation is also discovered in the experiments.

• Education of Primary School Mathematics
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• v.3 no.1
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• pp.37-45
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• 1999

This paper investigates the comparative effectiveness of two kinds of instructional methods in transfer of mathematics learning: one based on the situated cognition, ie. situated learning and the other based on traditional learning. Two classes of second graders studied the instruction about 3-digit addition and subtraction. After that, they completed two written tests and a real situation test. As a result. no significant differences were found between the two group's performance on the written test 1 and real situation test. But the situated learning group performed significantly better on the performance of story problem than traditional group. This result indicated that the situated learning made improvement in transfer of mathematic loaming. As a result of interviews with 12 children, the situated loaming group's children were able to use contextual resources in solving real situation as well as story problems.

• Journal of Drive and Control
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• v.9 no.4
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• pp.42-51
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• 2012

Variable displacement vane-type oil pumps represent one of the most innovative pump types for industrial applications, especially for engine lubrication systems. This paper deals with a modeling method for theoretical flow rate investigation of a typical variable displacement vane-type oil pump. This theoretical model is based on the pump geometric design and dynamic analyses. It can be considered as mandatory steps for a deeper understanding of the pump operation as well as for effectively implementing the pump control mechanisms to satisfy the urgent demands of engine lubrication systems. The developed pump model is finally illustrated by numerical simulations.

• Journal of Fisheries and Marine Sciences Education
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• v.16 no.1
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• pp.50-59
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• 2004

Recently, many more fisheries and shipping high school students have entered college than those of the past. But, this trend could be attributed to the easy and various forms of selection for college admission. Thus the examinations of the college scholastic ability 2005 have added to the vocational search ability including verbal ability, mathematic ability, foreign language ability and inquiry ability. The vocational search ability in fisheries and shipping field is concluded the general fisheries science, general maritime science, general marine science and fisheries and shipping information management. This study analyzed the questions of the fisheries and shipping subject of vocational search field with high school 2nd students on October 2003. In result, this study identified some needed basic scholastic ability for fisheries and shipping high school students.

• East Asian mathematical journal
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• v.28 no.4
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• pp.353-361
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• 2012

In this paper, we apply mathematising activities to geometry contents of corrent in middle and high school in order to actualize learning and teaching through Freudenthal's, Piaget's, and Van Hieles's mathematising among many theories affecting teaching and learning methods. Learners find out mathematical idea through the activities of mathematising that interprete mathematical problemm. And we derive mathematic through the experience of vertical mathematising that expresses it. Based on it, Freudenthal's progressive mathematising process, etc are used in doing the activities of applicative mathematising.