• Journal of The Korean Association For Science Education
• /
• v.23 no.2
• /
• pp.200-213
• /
• 2003

This study is one of the successive studies for investigating students' processes of generating and evaluating scientific hypothesis. In this study, I analyzed the characteristics of students' experimental design to test whether the given hypotheses were correct or not. As results, it was found that (1) 3 components (experimental method, prediction of the result of experiment, evaluation of hypothesis) were needed to complete description of the experimental design, (2) students tried to test hypothesis considered as being correct as well as hypothesis considered as being false by students, (3) student tried to confirm hypothesis, which was considered as being correct, based on theoretical approach rather than experimental approach, (4) students' experimental design could be classified as two types, that is, direct experimental testing and comparative experimental design, and the latter could be classified as two subtypes; positive comparative one and negative comparative one, (5) students showed tendency to design positive comparative experiment when they considered hypothesis as being correct, and vise versa, (6) students preferred the prediction which could confirm the hypothesis when they considered the hypothesis as being correct, and vise versa, (7) many students rejected contradicting prediction even though they did not actually conduct experiment yet.

• Korean Journal of Construction Engineering and Management
• /
• v.6 no.6 s.28
• /
• pp.115-123
• /
• 2005

Design of steel $bridge^{\circ}AEs$ temporary works has conducted relying on the experiences of engineers based on the previous similar projects. Consequently, there have been arguments against over-design of temporary bents to be required at the actual construction sites, and unnecessary design changes have been issued at the construction stage. In this study, we have developed an optimum design support system for temporary works of the steel bridge construction through establishing the database for the materials to be needed for implementation of temporary works. We've also improved the accuracy and efficiency of the works through the design optimization for temporary works, and contributed to reduce design changes as well as to utilize the design informations at the construction stage.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.12
• /
• pp.1843-1848
• /
• 2010

This paper presents an analysis of the design hypothesis of integration of parts from the viewpoint of axiomatic design. In parts integration, parts with the same functions are integrated into a single part. For the analysis, a motor actuator of an outside rear-view mirror with the type of an uncoupled design was used. The parts within the actuator are checked for determining the possibility of integration, by adopting the design hypothesis of integration of parts. The design hypothesis of integration of parts is based on a type of coupled design. However, the type of incomplete coupled design that resembles the type of an uncoupled design would be better than the type of a coupled design.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.4A
• /
• pp.487-495
• /
• 2008

The behavior of nose-deck system during launch was examined by three dimensionless launching parameters, such as the relative flexural stiffness, the relative nose weight, and the relative nose length. The techniques of optimizing the launching nose were illustrated and equations of relationship between relative nose weight and relative nose length were derived under minimum conditions of the launching negative and positive moment. Equations of maximum positive and negative moment were suggested under the conditions. The optimum design method of the launching nose was proposed in launched continuous girder bridges. It was found that the ideal launching nose was to design that with the relative nose weight of 0.167 and the relative nose length of 0.836 to minimize absolute values of the positive and negative moment during launch.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.1
• /
• pp.1-11
• /
• 2013

In this study, in order to increase the span length, the temporary bridge which the center part of span is strengthened by small H-beam and the end part of span is strengthened by steel plate is designed and constructed. Real behavior of proposed temporary bridge is analyzed by field loading test. Analyzed shear buckling strengths and nonlinear behavior of suggested temporary bridge are compared with the those of general temporary bridge. From the field loading test results, it is analyzed that real static behavior of suggested temporary bridge is agree with the analyzed behavior which is considered in design process. Under the proposed design condition, it is investigated that the shear buckling strength of suggested temporary bridge is about 40% higher than that of general temporary bridge, and the ultimate strength of suggested temporary bridge is about higher than that of general temporary bridge. From the study results, it is concluded that the proposed temporary bridge can be applied by the needs of field condition.

• Communications of Mathematical Education
• /
• v.36 no.2
• /
• pp.287-311
• /
• 2022

This study was related to the cases in which pre-service elementary teachers designed math lessons tailored to math underachievers with learning trajectories and universal design for learning. Learning trajectories can be a basis to identify students' current state of understanding and development, and make a lesson plan responsively tailored to underachievers' state. And universal design for learning is a framework that removes potential barriers that may exist in math lessons from the time the lessons are planned, and guides the rich learning environment accessible to all learners. In order to provide an experience of designing math lessons considering the characteristics of math underachievers, this study required pre-service elementary teachers to create learning trajectories and make lesson plans with the principles of universal design for learning. The characteristics of the learning trajectories shown in the lesson plans and the results of applying the principles of universal design for learning were analyzed. By discussing the results, implications were derived regarding the necessity of lesson planning for math underachievers and the development of lesson planning competency of pre-service elementary mathematics teachers in teacher education.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.24 no.6
• /
• pp.645-654
• /
• 2011

Temporal supports is proposed for the large block construction of a double-deck truss girder of a bundle type cable-stayed bridge. The design force of the temporal bents cannot be evaluated by a conventional design procedure with gust factored static wind loads. The uplift forces in BS5400 also can not estimate the design forces of the temporal bents properly for the turbulent wind loads. A frequency-domain buffeting analysis is performed to evaluate the design forces of the temporal bents considering the interactions between the girder and temporal supports. Two cases of modeling are compared to estimate the stiffness contribution of temporal supports in determining design forces, i.e., an analysis model including temporal bents in the structural analysis modeling and an analysis model with fixed supports at the bent tops neglecting the stiffness of temporal bents. The consideration of bent stiffness usually generates smaller reaction forces than rigid support modeling. Consequently, the effectiveness and usefulness of the buffeting analysis procedure with full modeling of temporal supports are demonstrated for the design of a temporal bents of the construction of a bundle type cable-stayed bridge.

• Journal of the Korean Chemical Society
• /
• v.56 no.3
• /
• pp.371-377
• /
• 2012

In this study, open inquiry reports of 165 eighth graders in Daegu were analyzed in terms of content area, the types of inquiry hypothesis, and the types of inquiry variables. Before summer vacation, students learned about inquiry process and explored their own inquiry topic for two class hours. During summer vacation, students performed open inquiry including problem selection, designing and performing experiment, data collection, data analysis, and writing report. After the vacation, students submitted their reports, and answered to additional survey regarding the source of inquiry idea, the definition of hypothesis, and the most difficult step of inquiry process. As a result, chemistry was the most dominant content area of the reports and biology and life science were the next. 130 out of 165 reports included inquiry hypotheses, and most of them were predictive hypotheses. In many reports, dependent and independent variables could not be identified because of their ambiguity. However, inquiry variables described in experimental design, which were mostly categorical variables, were clearer than those described in inquiry subject and inquiry hypothesis. The most difficult step of inquiry process for students was to generate an idea for open inquiry.

• Journal of Advanced Marine Engineering and Technology
• /
• v.36 no.1
• /
• pp.118-125
• /
• 2012

In this paper, an approach to designing controllers for the tension/movement control of working robot to install a stringing wire cable is presented. To design a controller, when the robot moves a certain distance maintaining constant tension, the dynamic model of a stringing wire cable which considers effects of weights according to changing lengths is presented. Also the tension at startup of the working robot is studied by numerical analysis which is based on the equation of the dynamic wire model. From the dynamic model for a stringing wire cable, working robot for tension/movement control is suggested and designed a feedforward controller with a accelerator gain to suppress a mutual interference of the both tasks of tension/movement control. Depending on the operating conditions of the working robot, the effectiveness of the suggested system has been verified by the simulation and experimental results.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.16 no.3
• /
• pp.92-98
• /
• 2012

This study shows details of a specific space truss frame structure devised to carry out maintenance and repair temporary works in tunnels. The purpose of this study is to verify structural safety and function of the innovative truss structure through an analysis tool, i.e.. ABAQUS, which is a suite of software application for finite element analysis and computer aided engineering. And then optimized size, i.e., thickness and diameter of truss members is evaluated in practice. In this study, construction methods in the temporary works are additionally represented by using the new space truss frame structure.