• Proceedings of the KIEE Conference
• /
• 2005.05a
• /
• pp.266-268
• /
• 2005

Recently, the ability of sensing obstacles by oneself and creating suitable moving path in mobile robots are required to provide various kinds automation services. Therefore, in this paper, we studied the avoidance behavior of mobile robots from dynamic obstacles using potential function that minimizes distance and time. We examined the performance of the proposed algorithm by comparing the method of based on the geometrical experience in simulations.

• Research in Mathematical Education
• /
• v.2 no.1
• /
• pp.163-181
• /
• 1998

The paper deals with some aspects of early childhood geometry in the Czech Republic. Children's first geometrical experiences come from real life. In our opinion, there exist four types of geometrical experience which can be called the partition of space, the filling of space motion in space and the dimension of space. We distinguish three levels of the mathematical learning process: a spontaneous level, an operational level and a theoretical level.

• Research in Mathematical Education
• /
• v.1 no.2
• /
• pp.163-181
• /
• 1997

The paper deals with some aspects of early childhood geometry in the Czech Republic. Children's first geometrical experiences come from real life. In our opinion, there exist four types of geometrical experience which can be called the partition of space, the filling of space motion in space and the dimension of space. We distinguish three levels of the mathematical learning process: a spontaneous level, an operational level and a theoretical level.

• School Mathematics
• /
• v.1 no.1
• /
• pp.109-122
• /
• 1999

In this paper we give a description of students' obstacles in their learning of geometry, especially resulted from their confusing a physical drawing with a figure, a geometrical object which a physical drawing represents. In computer-based teaching-learning environment, we could relieve such obstacles through providing students for experiences in which they must focus on elements of a figure and relations of them. But there may be potential in computer-based environment if we offer students only visual experience for validity of geometrical gacts: students' lack of understanding for need of proof and experience of cognitive obstacles which is very important for students to reflect their thinking and activities. Thus an didactical treatment must follows, which we also give an example.

• Journal of Educational Research in Mathematics
• /
• v.23 no.4
• /
• pp.585-604
• /
• 2013

This study is based on the problem that most middle school students cannot recognize the generality of geometrical theorems even after having proved them. By considering this problem from the point of view of empirical verification, the particularity of geometrical representations, and the role of geometrical variables, we suggest that some experiences in dynamic geometry environment (DGE) can help students to recognize the generality of geometrical theorems. That is, this study aims to observe students' cognitive changes related to their recognition of the generality and to provide some educational implications by making students experience some geometrical explorations in DGE. To do so, we selected three middle school students who couldn't recognize the generality of geometrical theorems although they completed their own proofs for the theorems. We provided them exploratory activities in DGE, and observed and analyzed their cognitive changes. Based on this analysis, we discussed the effects of DGE on studensts' recognition of the generality of geometrical theorems.

• Journal for History of Mathematics
• /
• v.17 no.1
• /
• pp.87-96
• /
• 2004

This article dealt with two approaches, algebraic and geometric approaches in terms of Pythagoreans theorem. As mathematics evolves, many theorems had been developed beginning with geometric approaches. However, the algebraic techniques that survive these days are so powerful and generalized in school curriculum. So, if students have more chances to see mathematical properties in geometrical ways, they can experience how beautiful and meaningful they are through the process of the advent of them. Also, it was to try to develop an insight into their applications to other problems.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.473-473
• /
• 2009

There have been many academic researches on the aerodynamic design of wind turbine based on blade element method (BEM) and momentum theory (MT, or actuating disk theory). However, in the real world, the turbine blade design requires many additional constraints more than theoretical analysis. The standard procedure is studied in the present paper to design new blades for the wind turbine system ranged from the small size from 1 to 10 kW. From the experience of full design of a 10 kW blade, the authors tried to set up a standard procedure for the aerodynamic design based on IEC 61400-2. Wind-turbine scale, rotating speed, and geometrical chord/twist distribution at the segmented span positions are calculated with a suitable BEM/MT code, and the geometrical shape of tip and root should be modified after considering various parameters: wing-tip vortex, aerodynamic noise, turbine efficiency, structural safety, convenience of fabrication, and even economic factor likes price, etc. The evaluated data is passed to the next procedure of structural design, but some of them should still be corresponded with each other: the fluid-structure interaction is one of those problems not yet solved, for example. Consequently, the design procedure of small wind-turbine blades is set up for the mass production of commercial products in this research.

• The Research Journal of the Costume Culture
• /
• v.7 no.5
• /
• pp.122-139
• /
• 1999

Paco Rabanne, who has created experimental and prophetic avant-garde fashion by cutting edge techniques and revolutionary new materials, is known as one of the most influential fashion designer of modern times. The purpose of this study is to analyze the various factors, including some major artistic movements, which influenced on the formative characteristics of Paco Rabanne\`s fashion design. First, Paco Rabanne\`s fantastic new materials is also influenced by his study in architecture and his own fantasies -which other people can hardly imagine- during his early childhood. Second, light one of the most important element in Paco Ranbanne\`s fashion design, shows some influence of medieval symbols of love and salvation. Third, the artistic trends which influenced on Paco Rabanne\`s fashion include surrealism, opart, and kinetic art. His use of new materials and avant -garde style represents the influence of surrealism. his experimental use of waving plastics and glittering metal during his early period is especially related with opart and kinetic art in the early 1960s which emphasize the artistic effect of light and movement. Fourth, the geometrical figures like triangles, rectangles, and circles represent the influence of Egyptian architecture like pyramids and the geometrical characteristics of Eguptian art. Fifth, Paco Rabanne\`s distinctive use of metal chains in his fashion shows the influence of the chain mail hauberk, the medieval knightly armour. By using the medieval material Paco Rabanne properly expressed the modern person\`s pain and suffering. Sixth, the ethnic elements of Egypt, Africa, Spain, and Japan reflect the experience in his former lives he insists he lived. The ethnic elements of his dresses emphasize the natural vitality and inheritance from the past.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.10a
• /
• pp.200-205
• /
• 1993

The automatic forming sequence design system can determine desirable operation sequences even if they have little experience in the design of cold forging process. This system is proposed,which generates forming sequence plans for the multistage cold forging of zxisymmetrical solid products. Since the process of metal forming can be considered as a transformation of geometry, treatment of the geometry of the product is a key in planning processes. Forming sequence for the part can be determined by means of primitive geometries such as cylinder,cone, convex, and concave. By utilizing this geometrical characteristics(diameter,height, and radius),the product geometry is expressed by a list of the pnmitive geometries. Accordingly, the forming sequence design is formulated as the search problem which starts with a billet geometry and finishes with a given product one. Using the developed system, the sequence drawing with all dimensions, which includes the proper sequence of operations for the part, is generated under the environment of AutoCAD. The preliminary choice of some feasible forming sequences can verify by using the finite element simulation.

• Proceedings of the KSME Conference
• /
• 2000.11b
• /
• pp.434-440
• /
• 2000

This study is focused on the performance prediction and design of the centrifugal pump with optimum shape. Design and analysis of centrifugal pump rely on experience of designer due to many fluid mechanical and geometrical variables. In this study, a design method was developed with experimental factors and analysed the method by comparition with 2nd-order vortex panel method. Impeller is the most important component affecting the performance of the centrifugal pump. The predicted total head for three cases, of which designs were determined by this method, agrees well with a particular commercial pump. This study shows that satisfactory performance of an optimal pump shape can be obtained through the automatic design routine.