• Magazine of the Korean Society of Agricultural Engineers
• /
• v.29 no.4
• /
• pp.73-92
• /
• 1987

Formulation of the geometric optimization for truss structures based on the elasticity theory turn out to be the nonlinear programming problem which has to deal with the cross-sectional area of the member and the coordinates of its nodes simultaneously. A few techniques have been proposed and adopted for the analysis of this nonlinear programming problem for the time being. These techniques, however, bear some limitations on truss shapes, loading conditions and design criteria for the practical application to real structures. A generalized algorithm for the geometric optimization of the truss structures, which can eliminate the above mentioned limitations, is developed in this study. The algorithm proposed utilizes the two-levels technique. In the first level which consists of two phases, the cross-sectional area of the truss member is optimized by transforming the nonlinear problem into SUMT, and solving SUMT utilizing the modified Newton Raphson method. In the second level, which also consists of two phases the geometric shape is optimized utillzing the unindirectional search technique of the Powell method which make it possible to minimize only the objective functlon. The algorithm proposed in this study is numerically tested for several truss structures with various shapes, loading conditions and design criteria, and compared with the results of the other algorithms to examine its applicability and stability. The numerical comparisons show that the two- levels algorithm proposed in this study is safely applicable to any design criteria, and the convergency rate is relatively fast and stable compared with other iteration methods for the geometric optimization of truss structures. It was found for the result of the shape optimization in this study to be decreased greatly in the weight of truss structures in comparison with the shape optimization of the truss utilizing the algorithm proposed with the other area optimum method.

• Journal of The Korean Association of Information Education
• /
• v.22 no.3
• /
• pp.385-396
• /
• 2018

This research supports the idea that manipulative devices can be an effective modality tool for learning abstract concepts involved with identifying geometric shapes and enhance learners' problem solving and motivation. Until recently specified manipulative device has been adapted only in traditional classroom environment and it has been very rare to find devices that is designed for online-basis. This study focused on designing and implementing an educational software which guide learners with geoboard in identification and characteristics of polygons. In addition to the function to draw and to delete various shapes, this software helps learners immediately assess the outcome. The results of the Delphi Technique show promising evidence for it being a very efficient means to learn geometric shapes and increase learners' motivation to learn the subject matter.

• Education of Primary School Mathematics
• /
• v.21 no.2
• /
• pp.209-221
• /
• 2018

Angle concepts have a multifaceted nature such as quantitative aspects as the amount of rotation, qualitative aspects as geometric shapes, and relationship aspects made with planes or lines. This study analysed angle concepts and introduction methods of angles in elementary mathematics textbooks which have been used from the Syllabus Period to the 2015 Revised Mathematics Curriculum. First, the concepts of angles in mathematics textbooks focus through the definitions, representations, and components of angles presented in mathematics textbooks are analyzed. Secondly, how various aspects of each angle are sequenced through the tasks or activties in the introduction of lesson is looked. As a result of analysis, the methods of introducing angles in the changes of mathematics textbooks have mainly focused on learning about geometric shapes and relations of components. In the mathematics classroom, students should experience various aspects of geometric shapes, rotations, relational aspects of points, lines and surfaces, and support and link them to form a wide range of concepts.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2022.10a
• /
• pp.225-228
• /
• 2022

The method of calculating the architectural design cost of the Korean Society of Architecture Policy considers the time spent during the design period. Therefore, faster design times can reduce design costs. As a result of a survey of students majoring in architecture, they felt tiredness from repeated floor plan drawings and difficulties in that there were many things to consider when floor plan drawing. In this paper, we implement a program that can automatically convert sketches into standardized floor plans during the architectural design process and a web app for user convenience. In the proposed method, when a user registers a sketch image through a web app, the program separates the space in the drawing through geometric shapes detection. Based on the dimensions and spatial information shown in the sketch, the outer and inner walls are displayed and the appropriate furniture is placed in the space. Through the proposed method, the design cost can be expected to be reduced by reducing the time of the drawing process in the architectural design stage, and 95.2% of architectural students expressed their intention to use the program.

• Architectural research
• /
• v.15 no.4
• /
• pp.207-214
• /
• 2013

A form-finding technique is proposed for three-dimensional spatial structures. Two-step discrete finite element (FE) mesh generator based on computer aided geometric design (CAGD) is introduced and used to control the shape of three-dimensional spatial structures. Mathematical programming technique is adopted to search new forms (or shapes) of spatial structures. For this purpose, the strain energy is introduced as the objective function to be minimized and the initial volume (or the initial weight) is considered as constraint function. Numerical examples are carried out to test the capability of the proposed form-finding techniques and provided as benchmark tests.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.32.6-32
• /
• 2002

The damage localization of the structural system using the natural frequency measurement only is proposed. The existing methods use the changes of mode shape, strain mode shape or curvature mode shape before and after the damage occurrence as these shapes carry the geometric information of the structure. Basically, the change of natural frequencies of the structure can be used as the indicator of the damage occurrence but not as the indicator of the damage location as the natural frequency changes does not carry the geometric information of the structure. In this research, the feedback scope method that measures the natural frequency changes of the structure with and without the feedback Ioo...

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.17 no.10
• /
• pp.2634-2645
• /
• 1993

Dome structures of pressure vessels subjected to internal pressure are usually analyzed by linear elastic theory assuming small deformation. Geometric and material nonlinear behaviors appear in actual dome structures because of large deformation and loads exceeding yield strength. In this paper, linear and nonlinear analyses were performed for various hemispherical and torispherical domes to check the effects of geometric and material nonliearity on the stress and displacement by the finite element method. The effect of the geometric nonlinearity decreased the stress levels a lot for very thin general torispherical domes, which enables more realistic and effective design. The material nonlinear effects are negligible for hemispherical and optimum torispherical domes, and those are large for most of the general torispherical domes.

• Journal of the Korean Professional Engineers Association
• /
• v.34 no.2
• /
• pp.10-13
• /
• 2001

Workpiece materials may be relatively easy to machine by traditional methods but workpiece geometry also may be a constraint. Many shapes that are geometrically difficult to handle conventionally may be candidates for nontraditional processes. Nontraditional processes provide new opportunities for product design innovation and productivity improvements. Difficult-to-machine materials of geometric shapes difficult o produce with traditional equipment and tooling, may often be easily and cost effectively machined using nontraditional processes. Notraditional machining processes are relative newcomers o the manufacturing arena. Nontraditional chemical solutions, or even electrolytic current as the working medium rather than a conventional cutting tool or abrasive to remove or shape materials.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.29 no.12 s.148
• /
• pp.1582-1594
• /
• 2005

The purpose of this study is to rediscover the value of form in fashion design by developing a new perspective of design appreciation. By examining and modifying the theories of Wolfflin and Belong, this paper tries to of for a new perspective for analyzing the characteristics of form in fashion designers' works. The three new perspective, Flat & Rounded, Closed & Opened and Part & Whole, can be used to analyze the formative aesthetic character of Vionnet's and Dior's works. Ten of Vionnet's and eleven of Dior's representative works selected and applied Delong's visual priority diagram to analyze their character. Vionnet and Dior, emphasized form and construction in their design and applied geometric shapes in their works. The main differences between Vionnet and Dior is that Vionnet's work transforms from geometric shapes in 2-dimentional space to drapery shapes in 3-dimensional space, Dior's work displays geometric shapes in 3-dimensional space. Vionnet created new formative art through the relationship between the clothes and human body. Vionnet's work has distinctively different qualities depending on whether the space is 2-dimensional or 3-dimensional showing transposition of form. In 2-dimensional space, Vionnet's works consist of triangles, rectangles and circles which are 'flat' and 'closed' in quality. These transform to solid forms by draping bias fabrics, which have a 'rounded' and 'open' quality. Dior tended to show artificial form rather than the natural lines of the body which is very different with Vionnet. Dior created clothes by using solid geometric form such as spheres, prisms, cylinders, pyramids and cubes in 3-dimensional space, which were visualized through constructive technique such as dart manipulation, boning, gathering, tucking, pleating, shirring and layering. Dior's works have their own form which does not relate with body shape. So his Works have a 'rounded' and 'closed' quality.

• Wind and Structures
• /
• v.9 no.2
• /
• pp.147-158
• /
• 2006

The purpose of this paper is to find a more accurate method to evaluate pedestrian wind by computational fluid dynamics approach. Previous computational fluid dynamics studies of wind environmental problems were mostly performed by simplified models, which only use simple geometric shapes, such as cubes and cylinders, to represent buildings and structures. However, to have more accurate and complete evaluation results, various shapes of blocking objects, such as trees, should also be taken into consideration. The aerodynamic effects of these various shapes of objects can decrease wind velocity and increase turbulence intensity. Previous studies simply omitted the errors generated from these various shapes of blocking objects. Adding real geometrical trees to the numerical models makes the calculating domain of CFD very complicated due to geometry generation and grid meshing problems. In this case the function of Porous Media Condition can solve the problem by adding trees into numerical models without increasing the mesh grids. The comparison results between numerical and wind tunnel model are close if the parameters of porous media condition are well adjusted.