• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.40 no.3
• /
• pp.185-193
• /
• 2003

The conventional parallelogram prediction uses only three previously traversed vertices in a single adjacent triangle; thus, the predicted vertex can be located at a biased position. Moreover, vortices on curved surfaces may not be predicted effectively since each parallelogram is assumed to lie on the same plane. In order to improve the prediction performance, we use all the neighboring vertices that precede the current vertex. After we order vortices using a vertex layer traversal algorithm, we estimate the current vertex position based on observations of the previously coded vertex positions in the layer traversal order. The difference between the original and the predicted vertex coordinate values is encoded by a uniform quantizer and an entropy coder. The proposed scheme demonstrates improved coding efficiency for various VRML test data.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.25 no.5
• /
• pp.321-328
• /
• 2016

Cranes are generally used to drop or lift equipment or materials. The present study focuses on equipment used for dropping and lifting the sonar system for undersea exploration. This study deals with a GA-based MATLAB$^{(R)}$ simulation for the design optimization of a new overboarding prototype with a two degree-of-freedom mechanism, including a parallelogram link, which is efficient in sonar system operation and maintenance. First, the strengths and weaknesses of the existing overboarding mechanisms are analyzed. The new mechanism to solve these problems is then suggested. For the proposed mechanism, the GA-based MATLAB$^{(R)}$ simulation technique is applied to the proposed mechanism to optimize the link lengths and the actuator lengths. By doing this, the mechanism cannot interfere in the hull's internal environment. Hence, the work range of motion (ROM) is satisfied, and good torque-angle properties are obtaind. The developed technology will be helpful in calculating the maximized output torque of the actuator for the application in practice using a similar type of the proposed mechanism.

• Journal of Educational Research in Mathematics
• /
• v.21 no.2
• /
• pp.181-199
• /
• 2011

The area formula for a plane figure represents the relations between the area and the lengths which determine the area of the figure. Students are supposed to understand the relations in it as well as to be able to find the area of a figure using the formula. This study investigates how 5th grade students understand the formulas for the area of triangle, rectangle and parallelogram, focusing on their understanding of functional relations in the formulas. The results show that students have insufficient understanding of the relations in the area formula, especially in the formula for the area of a triangle. Solving the problems assigned to them, students developed three types of strategies: Substituting numbers in the area formula, drawing and transforming figures, reasoning based on the relations between the variables in the formula. Substituting numbers in the formula and drawing and transforming figures were the preferred strategies of students. Only a few students tried to solve the problems by reasoning based on the relations between the variables in the formula. Only a few students were able to aware of the proportional relations between the area and the base, or the area and the height and no one was aware of the inverse relation between the base and the height.

• Journal of the Korean Ceramic Society
• /
• v.39 no.10
• /
• pp.907-911
• /
• 2002

Using the two-dimensional Wulff plot, the equilibrium shape of a sapphire crystal was investigated as a function of surface energy anisotropy. Depending on the relative values of surface energy for various facet planes, the projected shape of equilibrium sapphire was determined to be rectangle, parallelogram, hexagon or octagon. The results are compared with the experimentally observed shapes of internal cavities of submicron range in sapphire single crystals.

• Bulletin of the Korean Mathematical Society
• /
• v.51 no.1
• /
• pp.129-137
• /
• 2014

In this paper, a new proof of the following result is given: The product of the volumes of an origin-symmetric convex bodies K in $\mathbb{R}^2$ and of its polar body is minimal if and only if K is a parallelogram.

• Proceedings of the IEEK Conference
• /
• 2009.05a
• /
• pp.103-105
• /
• 2009

This paper presents a pseudorandom tag arrangement for improved RFID based mobile robot localization. First, four repetitive tag arrangements, including square, parallelogram, tilted square, and equilateral triangle, are examined. For each tag arrangement, the difficulty in tag installation and the problem of tag invisibility are discussed. Then, taking into account both tag invisibility and tag installation, a pseudorandom tag arrangement is proposed, which is inspired from a Sudoku puzzle. It is shown that the proposed tag arrangement exhibits spatial randomness quite successively without increased difficulty in installation.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.9
• /
• pp.1428-1435
• /
• 1989

In this paper we propose a new algorithm which extracts spatial arrangement information of texture elements in structural textures. In the proposed algorithm, by the use of projection information in several directions obtained from the texture image we can get two directions which determine the texture structure and the parallelogram grid which isolates texture elements. The isolated texture elements are analyzed and used to synthesize texture images. Computer simulation shows that the proposed method can extract proper spatial structure of the texture element even when the texture image is highly corrupted by additive noise.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.10b
• /
• pp.529-531
• /
• 2000

본 논문은 Geometry Compression 분야에서 다뤄지는 압축기법 중 delta encoding 과정을 보완하여 좀 더 높은 압축률을 얻고자 하는 vertex position prediction 과정에 대한 내용으로 구성되어 있다. 이것은 triangle strip 형태의 입력을 받아서 그 vertex data 중 position 정보들간의 delta encoding 과정을 예측 기법을 이용한 encoding 과정으로 대체하여 Huffman encoding 과정에서의 symbol 개수를 줄여 압축률을 향상시키자는 개념에서 출발한다. triangle strip 생성 기법 중 greedy algorithm을 적용한 후, 기존의 parallelogram 방식과 이 논문에서 새로이 제안하는 방식을 비교하여 보다 나은 압축 방식을 제시하는 것이 이 논문의 목적이다. 이 논문에서 제시하는 방식을 실험한 결과, 기존의 예측 기법에 비해 2.4% 정도의 향상을 보여주고 있다.

• Journal of Elementary Mathematics Education in Korea
• /
• v.15 no.2
• /
• pp.361-383
• /
• 2011

This study is on teaching about the areas of plane figures through open instruction, which aims to discover the pedagogical meanings and implications in the application of open methods to math classes by running the Math A & B classes regarding the areas of parallelogram, triangle, trapezoid and rhombus for fifth graders of elementary school through open instruction method and analyzing the educational process. This study led to the following results. First, it is most important to choose proper open-end questions for classes on open instruction methods. Teachers should focus on the roles of educational assistants and mediators in the communication among students. Second, teachers need to make lists of anticipated responses from students to lead them to discuss and focus on more valuable methods. Third, it is efficient to provide more individual tutoring sessions for the students of low educational level as the classes on open instruction methods are carried on. Fourth, students sometimes figured out more advanced solutions by justifying their solutions with explanations through discussions in the group sessions and regular classes. Fifth, most of students were found out to be much interested in the process of thinking and figuring out solutions through presentations and questions in classes and find it difficult to describe their thoughts.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.4
• /
• pp.353-360
• /
• 2015

Commercial drivers feel tired more than the general public, because their driving times are long and they experience more idle vibration. In this study, we developed a nonlinear model of a magnetic, linear spring seat suspension to determine the optimal design to improve ride comfort. The resonant frequency for the optimal design of the suspension was found to be 3.5 Hz, and the stiffness was analyzed through displacement-load experiments. Additionally, the vibration transmissibility was analyzed by the suspension stiffness, and the existing coil spring type vibration transmissibility was found to be 0.99. A parallelogram type magnetic spring was determined to result in a better performance than the existing spring with a vibration transmissibility of 0.823.