• Structural Engineering and Mechanics
• /
• v.9 no.3
• /
• pp.215-226
• /
• 2000

Computational procedure within the framework of return mapping technique has been presented to integrate the constitutive behavior of a concrete model. Developed by Ohtani and Chen, this concrete model is based on multiple hardening concept, and is rate-independent and associative. Consistent tangent operator suitable for finite element analysis is derived to preserve the rate of convergence. Accuracy of the integration technique is verified and compared with available experimental data. Computational efficiency is demonstrated by comparing with results based on elasto-plastic tangent.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.10
• /
• pp.208-217
• /
• 2003

In order to construct the extrusion die surface of T -shaped sections, an automatic surface construction method based on NURBS surface and area mapping method is proposed in the present work. In the present study, a center point for area mapping is determined by introducing the mapping concept based on constant area proportionality between original billet and final product. The characteristic points of inlet profile are determined using the traditional area mapping method and the root finding numerical method. The inlet and outlet profiles are precisely described with NURBS curves using the characteristic points of entry and exit sections. For the construction of NURBS surface, an interpolation method for the pre-determined two section curves has been developed to be used in the generation of interior control points and weights. To show the validity of the proposed method, automatic die surface generation is carried out for the T-shaped section and T-shaped section with rounded corners.

• Transactions of Materials Processing
• /
• v.12 no.4
• /
• pp.348-357
• /
• 2003

In order to construct the extrusion die surface of arbitrarily shaped sections, an automatic surface construction method based on NURBS surface and area mapping method is proposed in the present work. A center point fur area mapping is determined by introducing the mapping concept based on constant area proportionality between original billet and final product. The characteristic points of inlet profile are determined using the traditional area mapping method and the root finding numerical method. The inlet and outlet profiles are precisely described with NURBS curves using the characteristic points of entry and exit sections. For the construction of NURBS surface, an interpolation method for the pre-determined two section curves has been developed to be used in the generation of interior control points and weights. To show the validity of the proposed method, automatic die surface generation is carried out for the several kinds of shaped sections.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.1513-1518
• /
• 1996

A force reflecting hand controller can be used to provide more realistic information to the operator of a teleoperation system such as kinesthetic feedback from a slave robot. In this paper, a new design concept of a force reflecting 6-DOF hand controller utilizing the kinematic structure of a Stewart Platform is presented. Based on the optimal design technique of a Stewart Platform, a force reflecting hand controller has been designed and constructed to verify the technical feasibility of proposed design concept. In order to provide an operator with kinesthetic feedback information, a force mapping algorithm based on a reciprocal product of screws has been introduced. Finally, the technical feasibility of the design concept has been demonstrated through some of experimental results of the device under virtual environment on a real-time graphic system.

• Journal of Gifted/Talented Education
• /
• v.22 no.4
• /
• pp.893-916
• /
• 2012

This research investigates gifted students' mothers' rearing stress based on the concept mapping method. For this, 12 gifted students' mothers solicited, gathered and analyzed related statements, and then did multidimensional scaling and hierarchical cluster analysis. The stress value was .273 which was appropriate for the two level concept mapping study. In addition 101 mothers of gifted students rated for the rearing stresses they experience. Results were as follows. First, 79 concrete statements were solicited and as a result of concept mapping were categorized as 'burden and conflict as mothers of the gifted', 'possible negative characteristics due to the giftedness', and 'self-esteem and pressure by the title of the gifted'. Especially following items showed relatively high average: worrying about how to give the child a specific help for his/her career(M=4.65); worrying that she might be intervening too much in their child's behaviors(M=4.60); getting pressured supporting the child to get involved in the gifted education system continually(M=4.46); worrying if her child is not developing his/her talent enough due to the lack of time and money(M=4.44); being concerned that her high expectations might be putting her child under too much pressure (M=4.43). Implications of the study related to gifted education practices were discussed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.05a
• /
• pp.343-346
• /
• 2003

In order to construct the extrusion die surface of arbitrarily shaped sections, an automatic surface construction method based on NURBS surface and area mapping method is proposed in the present work. In the present study, a center point for area mapping is determined by introducing the marring concept based on constant area proportionality between original billet and final product. The characteristic points of inlet profile is determined using the traditional area mapping method and the root finding numerical method. The inlet and outlet profiles are precisely described with NURBS curves using the characteristic points of entry and exit sections. For the construction of NURBS surface, an interpolation method for the pre-determined two section curves has been developed to be used in the generation of interior control points and weights. To show the validity of the proposed method, automatic die surface generation is carried out for the several kinds of shaped sections.

• Korean Journal of Computational Design and Engineering
• /
• v.14 no.3
• /
• pp.159-167
• /
• 2009

For the robust exchange of parametric CAD model data, it is very important to perform mapping rightly and accurately between different CAD models. However, data model mapping is usually performed on a case-by-case basis. This results in the problem that mapping quality fluctuates very widely depending on the abilities of developers. In order to solve this problem, the concept of symantic distance is adapted and applied to the translation of parametric CAD model data in order to measure the difference between different CAD models quantitatively in a computer-interpretable form and systematize the mapping process.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.19 no.5
• /
• pp.695-698
• /
• 2009

In this paper, we introduce the concept of fuzzy r-generalized open sets which are generalizations of fuzzy r-open sets defined by Lee and Lee [2] and obtain some basic properties of their structures. Also we introduce and study the concepts of fuzzy r-generalized continuous mapping, fuzzy r-generalized open mapping and fuzzy r-generalized closed mapping.

• IE interfaces
• /
• v.22 no.1
• /
• pp.17-25
• /
• 2009

In mobile device's user interface, menu organization is very important as well as menu structure because small display of mobile device. Menu items should be organized based on user knowledge structure to design user-centered interface. Traditionally, MDS (Multidimensional Scaling) have been most often used to expose users' perceived organization of menu items. But, information that MDS reveals is just relative spatial location of concepts and not relevant to concepts connection. Unlike MDS, Trajectory Mapping explicitly finds users' cognitive links between perceived concepts. This study proposes a Trajectory Mapping technique for eliciting knowledge structure, especially a set of cognitive pathways linking menu items, from end user. With twelve participants, MDS and Trajectory Mapping were conducted using cellular phone's menu items. And user knowledge structure was analyzed through Visual Concept Map that combination of results of MDS and Trajectory Mapping. After then, menu items were organized according to users' perceived organization. Empirical usability test was also conducted. The results of usability test showed that usability, in terms of task performance time, number of errors, and satisfaction, for newly organized interface was significantly improved compare to original interface. The methodology of this study is expected to be applicable to design a user-centered interface. In other words, Trajectory Mapping technique can be used as a design tool of user interface for imposing user knowledge structure on the interface.

• Journal of the Korean Chemical Society
• /
• v.51 no.2
• /
• pp.186-192
• /
• 2007

In this study, the effects of concept mapping on the preservice elementary teachers' achievement, conceptual understanding, anxiety toward science, and science teaching efficacy belief were investigated in the undergraduate general chemistry course. The aptitude-treatment interaction (ATI) between preservice teachers' learning approach and concept mapping strategy was also investigated. Sixty-nine freshmen from a university of education were assigned to a control group and a treatment group. Tests regarding students' learning approach, anxiety toward science, and science teaching efficacy belief were administered as pretests. Treatment lasted for 9 weeks. In every class, students in the treatment group constructed concept maps, while those in the control group solved the problems of the textbook after the lecture. After the instructions, tests of achievement, conceptual understanding, anxiety toward science, and science teaching efficacy beliefs were administered. The results indicated that students in the treatment group significantly outperformed those of the control group in the achievement test. In the conceptual understanding and the science teaching efficacy beliefs, however, no statistically significant differences were found between two groups. Students of the treatment group showed significantly higher anxiety than their counterpart in the test of anxiety toward science. No aptitudetreatment interaction between students' learning approach and the concept mapping strategy was found.