• Journal of the Korean School Mathematics Society
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• v.17 no.2
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• pp.167-191
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• 2014

In this study, we investigate the term-sets of 'base' or 'bottom': 'the bottom side of a polygon' and 'the base side (of a geometrical figure)'. And we study the concept of 'the base area' in the solid figures and the formula of 'the bottom dimensions'. We start from the 6th grade math problem: 'Find the bottom dimension of the rectangular.' The primary answer is that it does not use the term('the bottom dimensions') in the elementary mathematics. However, in the middle school mathematics, 'the base area' is used as means of 'the area of one bottom side', which is not explained anywhere from the elementary mathematics to middle school mathematics. In addition, the base is defined and 'the surface area' and 'the side area' is taught in the elementary mathematics, so we naturally think of 'the base area'. Therefore we first investigate the term-sets of 'base' or 'bottom' which has two elements: 'the bottom side of a polygon' and 'the base side (of a geometrical figure)'. Next we discuss 'the base area' through curriculum and textbooks, dictionary definitions and so on. In addition, we survey pre-service teachers and teachers about the solid figures and analyse the understanding of 'the base side' and 'the base area' comparatively. In particular, we compare the changes and the tendency of correct answers from the first question to the last question. As a result, we verify 'the cognitive gap' between the elementary mathematics and the middle school mathematics, we suggest the teaching of 'the base area' and succession subjects to teach figure domain in the elementary mathematics.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.4
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• pp.581-585
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• 2011

This study investigated the quality of muffin prepared with various concentrations of freeze dried-perilla leaves (Perilla frutescens var. japonica HARA) powder. Muffin was prepared by addition of 0, 3, 6 and 9% powder to the flour of basic formulation. The weight of muffin decreased with increase in freeze dried-perilla leaves powder concentration, but no constant tendency in the bottom and upper dimensions by its addition was found. The height and baking loss rate of the muffin increased with increase in the powder concentration but with no significant differences. Lightness and yellowness of muffin decreased as the concentration of the powder increased, whereas no significant differences in the redness was found with increased powder concentration. The hardness of muffin increased, and springiness decreased with increase in the powder concentration, although not significant. The cohesiveness, gumminess and chewiness showed no consistent tendency by addition of the powder. The antioxidative activity measured by 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of muffin increased as the concentration of the powder increased. The muffin contained 0~6% freeze dried-perilla leaves powder had acceptable sensory properties, such as color, taste, and overall acceptability. Results indicated that optimal concentration of freeze dried-perilla leaves powder into the muffin formula was 3~6% (w/w).

• Journal of Science Education
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• v.41 no.3
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• pp.480-498
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• 2017

This study analyzed the errors of 6th graders of elementary school in problem solving process of the measurement domain. By analyzing the errors that students make in solving difficult problems, this study tried to draw implications for teaching and learning that can help students reach their achievement standards. First, though the students were given enough time to deal with problems, the fact that about 30~60% of students, based upon the problems given, can't solve them show that they are struggling with a part of measurement domain. Second, it was confirmed that students' understanding of the unit of measurement, such as relationship between units, was low. Third, the students have a low understanding in terms of the fact that once the base is set in a triangle then the height can be set accordingly and from which multiple expressions, in obtaining the area of the triangle, can be driven.

• Journal of Science Education
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• v.36 no.2
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• pp.369-380
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• 2012

The purpose of this study was to investigate middle students' conceptions of buoyancy. The questionnaires composed of 9 items which asked the reasons for situations with buoyancy; recognized of buoyancy, the facts affecting buoyancy(bottom of the Area of the object, the shape of the object, the depth of the object in the water, amount of water, the degree of the object submerged in the water, volume of the object, weigh of the object), the relationship between the amount of replaced fluid and buoyancy. The subjects were 140 students from the Busan Area who answered questionnaires composed of 9 items which asked the reasons for situations with buoyancy. Among the 140, 132 students were selected who answered all of question in the test. The students' answer types were follow: 1. Related to the shape of the submerged object, students answered that buoynacy depended on the bottom dimensions or the surface area of the object. 2. Students confused press, water press and buoyancy, who answered buoyancy was great when the water press was great. 3. Students answered that the weight and the size of the buoyancy of the object was same in the water. 4. Students answered, gravity was smaller in the water. Students recognized the existence of buoyancy but the reason of the answer depend on their experience. Also students answered using the words that water pressure, pressure, force instead of buoyancy. Students didn't understand the factors affecting the buoyancy. Many students responded that buoyancy was changed depend on weight of object, sinking depth, shape and others. It was considered that these responses didn't understand the cause of buoyancy.