• Fashion & Textile Research Journal
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• v.8 no.6
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• pp.727-732
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• 2006

The purpose of this study was to investigate the effects of flame-proof clothing on physiological responses and subjective sensation. We measured rectal temperatures, local skin temperature, clothing microclimate, blood pressure, heart rate, body weight loss and subjective sensation during 90 minutes (30 min of rest, 45 min of exercise and 15 min of recovery periods). Seven male subjects wore flame-proof clothing or reformed flame-proof clothing under the environmental condition of $35{\pm}1^{\circ}C$, $45{\pm}5%$ RH and $25{\pm}1^{\circ}C$, $50{\pm}5%$ RH. The results of this study were as follows; Rectal temperature, mean skin temperature, clothing microclimate and blood pressure were significantly lower levels in reformed flame-proof clothing. Heart rate and body weight loss were also showed lower levels. Subjects replied less hot, less uncomfortable and less wet in wearing a reformed flame-proof clothing. Our present results suggest that the ventilation through of gusset in underarm seam and zipper in sideseam of slacks are qualitatively useful for physiological needs.

• The Mathematical Education
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• v.37 no.1
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• pp.73-85
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• 1998

The purpose of this study is to investigate the understanding of middle school students on the meaning of proof and to suggest a teaching method to improve their understanding based on three levels identified by Kunimune as follows: Level I to think that experimental method is enough for justifying proof, Level II to think that deductive method is necessary for justifying proof, Level III to understand the meaning of deductive system. The conclusions of this study are as follows: First, only 13% of 8th graders and 22% of 9th graders are on level II. Second, although about 50% students understand the meaning of hypothesis, conclusion, and proof, they can't understand the necessity of deductive proof. This conclusion implies that the necessity of deductive proof needs to be taught to the middle school students. One of the teaching methods on the necessity of proof is to compare the nature of experimental method and deductive proof method by providing their weak and strong points respectively.

• Journal of Educational Research in Mathematics
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• v.16 no.4
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• pp.327-344
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• 2006

This study examined the proof levels and understanding of constituents of proving by three mathematically gifted 6th grade korean students, who belonged to the highest 1% in elementary school, through observation and interviews on the problem-solving process in relation to constructing a rectangle of which area equals the sum of two other rectangles. We assigned the students with Clairaut's geometric problems and analyzed their proof levels and their difficulties in thinking related to the understanding of constituents of proving. Analysis of data was made based on the proof level suggested by Waring (2000) and the constituents of proving presented by Galbraith(1981), Dreyfus & Hadas(1987), Seo(1999). As a result, we found out that the students recognized the meaning and necessity of proof, and they peformed some geometric proofs if only they had teacher's proper intervention.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.3
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• pp.129-136
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• 2000

In the side of military purpose, the explosion proof concrete, which contributes to protect the military facilities from damages due to the explosion of bomb and to maintain their shapes, is required to develop, Therefore. in this paper, mechanical and explosion-proof properties of concrete are tested under various steel fiber contents and member size. According to the experimental results, compressive, tensile and flexural strength gain higher levels with an increase in fiber contents. It shows that energy bearing capacities are higher with an increase in fiber contents. Especially. it is confirmed that slurry infiltrated fiber concrete(SIFCON) gains high strength and has high energy bearing capacities. SIFCON is expected to be applied in the construction of explosion proof structures.

• Journal of Educational Research in Mathematics
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• v.9 no.1
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• pp.245-261
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• 1999

Proof is an essential characteristic of mathematics and as such should be a key component in mathematics education. But, teaching proof in school mathematics have been unsuccessful for many students. The traditional approach to proofs stresses formal logic and rigorous proof. Thus, most students have difficulties of the concept of proof and students' experiences with proof do not seem meaningful to them. However, different views of proof were asserted in the reassessment of the foundations of mathematics and the nature of mathematical truth. These different views of justification need to be reflected in demonstrative geometry classes. The purpose of this study is to characterize the types of students' justification in demonstrative geometry classes taught using dynamic software. The types of justification can be organized into three categories : empirical justification, deductive justification, and authoritarian justification. Empirical justification are based on evidence from examples, whereas deductive justification are based logical reasoning. If we assume that a strong understanding of demonstrative geometry is shown when empirical justification and deductive justification coexist and benefit from each other, then students' justification should not only some empirical basis but also use chains of deductive reasoning. Thus, interaction between empirical and deductive justification is important. Dynamic geometry software can be used to design the approach to justification that can be successful in moving students toward meaningful justification of ideas. Interactive geometry software can connect visual and empirical justification to higher levels of geometric justification with logical arguments in formal proof.

• School Mathematics
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• v.18 no.4
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• pp.749-771
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• 2016

The purpose of this study is to analyze mathematical tasks of Korea and the USA textbooks focused on conditions for parallelograms. In this study, structures of task, types of proof and reasoning, and levels of cognitive demand are investigated. The conclusion is as follows: First, with respect to structures of task, structures presented in the USA textbooks are more diverse. Second, with respect to types of proof and reasoning, Korea and the USA prefer IC task and DA task. And task types presented in the USA textbooks are more diverse. Third, with respect to levels of cognitive demand, in both Korea and the USA textbooks, PNC task and PWC task account most. And compared to the USA, Korea prefer algorithms. In addition, we find out implications for reconstruction of Korea textbook. It is as follows: First, with respect to structures of task and types of proof and reasoning, the diversity of composition needs to be raised. Second, with respect to levels of cognitive demand, the concentration in PNC task needs to be declined. And levels of cognitive demand on types of tasks need to be reconsidered. Third, with respect to tasks' topic and material, internal and external connectivities of mathematics need to be strengthened.

• Journal of Educational Research in Mathematics
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• v.14 no.3
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• pp.239-266
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• 2004

This article presents new perspectives for analysing and diagnosing students' mathematical errors on the basis of Pascaul-Leone's neo-Piagetian theory. Although Pascaul-Leone's theory is a cognitive developmental theory, its psychological mechanism gives us new insights on mathematical errors. We analyze mathematical errors in the domain of proof problem solving comparing Pascaul-Leone's psychological mechanism with mathematical errors and diagnose misleading factors using Schoenfeld's levels of analysis and structure and fuzzy cognitive map(FCM). FCM can present with cause and effect among preconceptions or misconceptions that students have about prerequisite proof knowledge and problem solving. Conclusions could be summarized as follows: 1) Students' mathematical errors on proof problem solving and LC learning structures have the same nature. 2) Structures in items of students' mathematical errors and misleading factor structures in cognitive tasks affect mental processes with the same activation mechanism. 3) LC learning structures were activated preferentially in knowledge structures by F operator. With the same activation mechanism, the process students' mathematical errors were activated firstly among conceptions could be explained.

• Journal of the Korea Furniture Society
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• v.14 no.2
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• pp.31-38
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• 2003

This study was carried out to investigate characteristics of wood-based panels and wood-cement board for the possible uses as flooring and wall materials. The optimum cement/wood ratio(C/W ratio) of wood~cement board manufactured by clamp-pressing was from 2.7 to 3.2. The dimesional stability was superior in the C/W ratio of 3.2. Particularly, the dimensional stability of cement board using fine particle for particleboard face layer was favorable through three levels of C/W ratio. According to types of wooden material, bending strength of cement board using coarse particle for particleboard core layer or old newspaper(ONP) fiber was relatively higher than others. Thermal conductivities of wood-cement boards were no lower than that of gypsum board, and higher than those of plywood and boards. In case of wood-cement board of the C/W ratio of 2.7, the fire-proof performances of cement composite boards were greater than that of gypsum board, and weight loss reached to about a half of gypsum board. Then, wood-cement boards showed superior fire-proof performance compared to wood-based panels.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.3
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• pp.139-146
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• 2003

The objective of the presented study is to develop an efficient procedure of proof load testing for existing bridges. By analytical methods, some of these bridges are not adequate to carry normal highway traffic. However, the actual load carrying capacity is often much higher than what can be determined by conventional analysis. Proof load testing can reveal the hidden strength reserve and thus verify the adequacy of the tested bridge. Proof load level required for meaningful tests should be sufficiently higher than legal load. In the state of Michigan, the legal 11-axle truck can weigh up to 685 kN. In this study, a combination of two military tanks and two Michigan 11-axle trucks was used. The proof loads were gradually increased to ensure the safety of the test. After each move, measurements were taken. For the considered bridge, stress levels were rather low compared to pre-test analysis results. This is due to incorrect material strength, structural contribution of nonstructural components such as parapets and railings, and partially fixed supports.

• Journal of Educational Research in Mathematics
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• v.21 no.2
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• pp.105-120
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• 2011

This research intends to analyse how mathematically gifted 8th graders (age 14) discover and proof the properties on the sum of face angles of polyhedron. In this research, the problems on the sum of face angles of polyhedrons were given to 36 gifted students, and their discovery and proof processes were analysed on the basis of their the activity sheets and the researcher's observation. The discovery and proof processes the gifted students made were categorized, and levels revealed in their processes were analysed.