• Journal of the Korean School Mathematics Society
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• v.4 no.1
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• pp.103-114
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• 2001

The purpose of this study is to develop learning materials for functional concept on variable and to verify the effect of how well students could learn functional concept after they studied with those materials. To accomplish the purpose of this study, I developed learning materials and after teaching students with them. I have concluded the followings : First, there was little effect in teaching functional concept on variable between two experimental groups, whereas teaching functional concept had greater effect on forming functional concept in high level groups in those two experimental groups. Second, teaching functional concept on variable had little effect on students' understanding of functional concept and perfecting tables in Black box, graph, and mathematical problems, whereas there was much effect in students' understanding functional concept and solving relation formula, image, and range problems related to everyday life or general things. On the basis of the problems which appeared in the process of this study, the following can be suggested : First, we should develop learning materials fit for low level students so that they could understand functional concept. Second, we should continue to teach the basic problems like solving relation formula, image, and range, and understanding functional concept in graph until students are able to understand them exactly. Third, since the goals of Unit Function in a middle school textbook is to solve problems related to everyday life through functional thinking, there should be change in constructing systematic contents of Unit Function in a middle school textbook.

• Communications of Mathematical Education
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• v.23 no.3
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• pp.545-562
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• 2009

This study is trying to analyze characteristics of mathematical thinking processes of the mathematical gifted students in an objective and a systematic way, by using "Protocol Analysis Method"and "Problem Behavior Graph" which is suggested by Newell and Simon as a qualitative analysis. In this study, four middle school students with high achievement in math were selected as subjects-two students for mathematical gifted group and the other two for control group also with high scores in math. The thinking characteristics of the four subjects, shown in the course of solving problems, were elicited, analyzed and compared, through the use of the creative test questionnaires which were supposed to clearly reveal the characteristics of mathematical gifted students' thinking processes. The results showed that there were several differences between the two groups-the mathematical gifted student group and their control group in their mathematical talents. From these case studies, we could say that it is significant to find out the characteristics of mathematical thinking processes of the mathematical gifted students in a more scientific way, in the sense that this result can be very useful to provide them with the chances to get more proper education by making clear the nature of thinking processes of the mathematical gifted students.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.34-44
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• 1998

It is clear that when an automobile negotiates a curve the lateral acceleration causes an increase in tire normal load for the wheels on the outside of the curve and a decrease in load for the inside wheels. However, just how the details of the suspension linkages and the parameters of the springs and shock absorbers affect the dynamics of the load transfer os not easily understood. One even encounters the false idea that since it is the compression and extension of the main suspension springs spring body role which largely determines the changes in normal load, of roll could be reduced, the load transfer would also be reduced. Using free body diagrams, one can explain quite clearly how the load is transferred for steady state cornering, and, using complex multibody models of particular vehicles one can simulate in good fidelity how load transfer occurs dynamically. Here we adopt a middle ground by using the concept of roll center and using a series of half-car bond graph models to point out main effects. Since bond graph junction structures automatically and consistently constrain geometric and force variables simultaneously, they can be used to point out hidden assumptions of other simplified vehicle models.

• Kyungpook Mathematical Journal
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• v.57 no.2
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• pp.301-307
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• 2017

In this paper, we solve the following four graph equations $L^k(G)=H{\oplus}J$; $M(G)=H{\oplus}J$; ${\bar{L^k(G)}}=H{\oplus}J$ and ${\bar{M(G)}}=H{\oplus}J$, where J is $nK_2$ for $n{\geq}1$. Here, the equality symbol = means the isomorphism between the corresponding graphs. In particular, we shall obtain all pairs of graphs (G, H), which satisfy the above mentioned equations, upto isomorphism.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.609-614
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• 1989

A collision avoidance algorithm based on a heuristic graph search and subgoals is presented. The joint angle space is quantized into cells. The evaluation function for a heuristic search is defined by the sum of the distance between the links of a manipulator and middle planes among the obstables and the distance between the end-effector and the subgoals on desired trajectory. These subgoals reduce the combinatorial explosion in the search space. This method enables us to avoid a dead-lock in searching. Its effectiveness has been verified by simulation studies.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1413-1416
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• 2014

A novel topological index (TG Index) has been introduced. The graphical matrix representation of the TG index includes the use of directed subgraphs for the first time in graph theory literature. The application of the TG index on certain properties of polyenes yielded very well correlation data.

• Korean Journal of Applied Biomechanics
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• v.12 no.1
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• pp.205-219
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• 2002

This research seeks to identify the plantar pressure distribution graph and change in force in connection with effective golf drive strokes and thus to help ordinary golfers have appropriate understanding on the moving of the center of weight and learn desirable drive swing movements. To this end, we conducted surveys on five excellent golfers to analyze the plantar pressure applied when performing golf drive strokes, and suggested dynamic variables quantitatively. 1) Our research presents the desire movements as follows. For the time change in connection with the whole movement, as a golfer raises the club head horizontally low above ground from the address to the top swing, he makes a semicircle using the left elbow joint and shaft and slowly turns his body, thus lengthening the time. And, as the golfer twists the right waist from the middle swing to the impact with the head taking address movement, and does a quick movement, thus shortening the time. 2) For the change in pressure distribution by phase, to strike a strong shot with his weight imposed from the middle swing to the impact, a golfer uses centrifugal force, fixes his left foot, and makes impact. This showed greater pressure distribution on the left sole than on the right sole. 3) For the force distribution graph by phase, the force in the sole from the address to halfway swing movements is distributed to the left foot with 46% and to the right foot with 54%. And, with the starting of down swing, as the weight shifts to the left foot, the force is distributed to the left sole with 58%. Thus, during the impact and follow through movements, it is desirable for a golfer to allow his left foot to take the weight with the right foot balancing the body. 4) The maximum pressure distribution and average of the maximum force in connection with the whole movement changed as the left (foot) and right (foot) supported opposing force, and the maximum pressure distribution also showed much greater on the left sole.

• Journal of the Korean earth science society
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• v.29 no.6
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• pp.487-494
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• 2008

The purpose of this study was to investigate the effects of MBL experiment instruction on the 7th graders' scientific inquiry skills and graph construction and interpretation ability in the unit "Elements and movement of sea water". Results are as follows: First, this study analyzed the influence on students' scientific inquiry skill after having six MBL instructional classes. The result showed a significant difference in the scientific inquiry skills between the experimental group and the control group, which implies that the instruction using MBL was an effective way to improve students' scientific inquiry skills. Second, this study also analyzed the influence on students' abilities to construct and interpret graphs. The result did not show any significant differences between the experimental group and the control group in the ability to construct graphs. But it showed significant differences in the ability to interpretgraphs, which means that instruction using MBL was an effective way to improve students' ability to interpret graphs.

• Journal of Gifted/Talented Education
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• v.21 no.2
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• pp.269-286
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• 2011

The purpose of this thesis is to examine difficulties students face in the inquiry activities of quadratic surface throughout mathematically gifted students' analogical inference and the influence of Cabri 3D in students' inquiry activities. For this examination, students' inquiry activities were observed, data of inferring quadratic surface process was analyzed, and students were interviewed in the middle of and at the end of their activities. The result of this thesis is as following: First, students had difficulties to come up with quadratic surfaced graph in the inquiry activity of quadratic surface and express the standard type equation. Secondly, students had difficulties confirming the process of inferred quadratic surface. Especially, students struggled finding out the difference between the inferred quadratic surface and the existing quadratic surface and the cause of it. Thirdly, applying Cabri 3D helped students to think of quadratic surface graph, however, since it could not express the quadratic surface graph in a perfect form, it is hard to say that Cabri 3D is helpful in the process of confirming students' inferred quadratic surface.

• Korean Journal of Environment and Ecology
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• v.25 no.3
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• pp.412-420
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• 2011

This study was conducted to quantitatively analyze the temporal change of green space network at multi-scales from 1975 to 2006 with the application of graph theory in Seoul, Korea. Remarkable change of connectivity was detected in green space networks at the scale ranging from 1,000 ~ 1,600 m during 30 years. Green spaces and their networks have been restoring after 1990 since forest areas had been fragmented in 1975. In 2006, we identified the important core habitat areas that can sustain diverse wildlife species and stepping stones composed of small patches that can link these core habitat areas. Green spaces showed high correlation with the relative importance value of green space connectivity. So, this study could graphically represent green space networks of Seoul City. Green spaces of core areas distributed at the northern and southern boundary, and those of stepping stones possessing the high value of betweenness centrality consisted at the middle, eastern and western boundary. These results indicate that green space network can be graphically and quantitatively explained by degree centrality, betweenness centrality and relative importance value of connectivity with the application of graph theory.