• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2002.10a
• /
• pp.120-128
• /
• 2002

In order to analyze shell structures more accurately and effectively, a hybrid 4-node quadrilateral shell element is formulated. The element includes the frilling degrees of freedom and the independent parameter terms of the stress resultants are appropriately selected to overcome some of the shortcomings of the standard 4-node quadrilateral elements. In order to show the accuracy and convergent characteristics of the proposed shell element, three numerical examples are analyzed and the results are compared with the existed. As a result of this study, following conclusions are obtained. (1)Analysis results by the proposed element are less sensitive to the element geometric distortion. (2)The proposed element does not produce any spurious zero-energy modes

• Proceedings of the KIEE Conference
• /
• 1998.07c
• /
• pp.946-948
• /
• 1998

The distance relay is very important for transmission line protection. A quadrilateral zone shape is used mainly for a modern digital distance relay. The shape of quadrilateral is vendor specific. At the stage of design, the shape is determined considering all possible types of faults and diverse configurations of system. Also this type relay must be designed to avoid the operation by a sound phase at single-Phase-to-ground fault, by a sound phase at two-phase-to-ground fault. The effect of a source impedance and a load impedance is another important factor to design. In this paper, a reliable zone shape which is appropriate for the KEPCO's transmission system is provided.

• Structural Engineering and Mechanics
• /
• v.33 no.4
• /
• pp.485-502
• /
• 2009

A new 8-node serendipity quadrilateral plate bending element (MQP8) based on the Mindlin-Reissner theory for the analysis of thin and moderately thick plate bending problems using Integrated Force Method is presented in this paper. The performance of this new element (MQP8) is studied for accuracy and convergence by analyzing many standard benchmark plate bending problems. This new element MQP8 performs excellent in both thin and moderately thick plate bending situations. And also this element is free from spurious/zero energy modes and free from shear locking problem.

• Nuclear Engineering and Technology
• /
• v.49 no.1
• /
• pp.29-42
• /
• 2017

The purpose of the present study is the presentation of the appropriate element and shape function in the solution of the neutron diffusion equation in two-dimensional (2D) geometries. To this end, the multigroup neutron diffusion equation is solved using the Galerkin finite element method in both rectangular and hexagonal reactor cores. The spatial discretization of the equation is performed using unstructured triangular and quadrilateral finite elements. Calculations are performed using both linear and quadratic approximations of shape function in the Galerkin finite element method, based on which results are compared. Using the power iteration method, the neutron flux distributions with the corresponding eigenvalue are obtained. The results are then validated against the valid results for IAEA-2D and BIBLIS-2D benchmark problems. To investigate the dependency of the results to the type and number of the elements, and shape function order, a sensitivity analysis of the calculations to the mentioned parameters is performed. It is shown that the triangular elements and second order of the shape function in each element give the best results in comparison to the other states.

• Journal of Fashion Business
• /
• v.6 no.3
• /
• pp.1-14
• /
• 2002

According to Scythian tradition, many burials contained numerous artifacts, from weapons and harness to everyday objects and a multiplicity of personal adornments. Most valuable of all is the Scythian Gold often lavishly decorated with precious stones. The detailed images on these pieces make it possible for us to picture the appearance of the Scythians, their clothes and weapons. Scythian Gold Plaques were attached to the fabric in such a way that when they moved with each movement of the wearer it created what must have been a dazzling sight in bright daylight. Scythian Gold Plaques were divided into several types according to the shape, animal style(curved beast shape, profile shape, head reversed over its back shape), round shape, quadrilateral form, star shape, flower shape, crescent shape, bundle shape, human appearance. Through the antique tombs bequests of Three Kingdom States hereby describe the original forms of their source of Baekje gold plaque were influenced by Scythe style. Like nearly all Scythian ornaments, such gold pieces were designed to maximize various magical powers and to signify the owner's importance relative to his fellow tribesmen.

• Journal of the Korea Society of Computer and Information
• /
• v.11 no.3
• /
• pp.187-192
• /
• 2006

We reviewed the collision event with pc-based shooting games and existing collision detection algorithms. Then we proposed a new collision check technique using a small quadrilateral unit. by which existing quadrilateral collision detection techniques can be made up for. For demonstration we implemented a simple shooting game having its screen output. We proved that the proposed technique can be applied to real computer games by means of showing the experimental results and screen outputs from implemented real games.

• Structural Engineering and Mechanics
• /
• v.83 no.2
• /
• pp.273-282
• /
• 2022

In this paper, we propose a new concept for error estimation in finite element solutions, which we call mode-based error estimation. The proposed error estimation predicts a posteriori error calculated by the difference between the direct finite element (FE) approximation and the recovered FE approximation. The mode-based FE formulation for the recently developed self-updated finite element is employed to calculate the recovered solution. The formulation is constructed by searching for optimal bending directions for each element, and deep learning is adopted to help find the optimal bending directions. Through various numerical examples using four-node quadrilateral finite elements, we demonstrate the improved predictive capability of the proposed error estimator compared with other competitive methods.

• Structural Engineering and Mechanics
• /
• v.25 no.2
• /
• pp.269-273
• /
• 2007

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2004.05a
• /
• pp.269-274
• /
• 2004

• Journal of the Korean School Mathematics Society
• /
• v.11 no.3
• /
• pp.513-541
• /
• 2008

The purposes of the study were to investigate whether the use of the Geometer's Sketchpad(GSP) is more effective than the use of traditional tools such as ruler and protractor to enhance eighth- grade students' understanding of quadrilaterals and geometric reasoning ability and to examine how the use of the software affects on the development of students' understanding and reasoning ability. According to the results of the posttest, there was a significant difference in student achievement between students using GSP and students using ruler and protractor. Students using GSP significantly outperformed students using ruler and protractor on the posttest. Student interview data showed that the use of the GSP was more effective in developing students' geometric reasoning ability. Students using GSP achieved higher degrees of acquisition for van Hiele level 2 and 3 than students using ruler and protractor. Dynamic visual representations and hands-on experiences provided in GSP learning environment helped students approach quadrilateral concepts more conceptually and realize their pre-existing conceptual errors and re-conceptualize their mathematical ideas.