• Journal of Advanced Marine Engineering and Technology
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• v.37 no.3
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• pp.274-281
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• 2013

The variable demand on the energy market requires a great flexibility in operating hydro turbines. However, Francis turbine operated at off-design conditions poses technical challenges related to large unsteady forces given by residual swirl and angular momentum. In order to improve the performance of a Francis turbine, the paper presents a numerical investigation of the 3D flow in the turbine at off-design conditions and discusses the influence of variable guide vane openings on the internal flow of a Francis turbine with the help of computational fluid dynamics. First, the internal flow characteristics of Francis turbine operated by varied guide vane angle at off design condition are computed and the optimal guide vane angle is obtained. Secondly, the Francis turbine is operated with guide vane number varies at the optimal guide vane angle. Finally, pressure contours and velocity distributions in the distributor are discussed and compared.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.326-331
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• 2004

The linear motion (LM) guide using ball bearing has many advantages compared with conventional sliding guides. Therefore, LM guide using ball bearing has been used widely to increase the accuracy of the position of a system. This research investigates dynamic characteristics of LM guide through mainly linear analysis. Linear analysis is accomplished by Lagrange equation and finite element method. And another trial that is nonlinear analysis about one mode of LM guide(bouncing mode) from Hertzian contact theory is accomplished in the latter half of this research. Through nonlinear analysis we could observe the softening characteristic due to the Hertzian contact nonlinearity.

• Journal of Korean Academy of Nursing Administration
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• v.14 no.1
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• pp.45-50
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• 2008

Purpose: This study was intended to determine how an in-patient guide movie enhanced the understanding of hospital life. Method: A non-equivalent control group post-test design was used for the study. The experimental group was allowed to watch the in-patient guide movie. The in-patient guide booklets were given to the control group for reading. The understanding and satisfaction of the respective programs were surveyed with questionnaires. The data was analyzed using SPSS. Result: The movie watching experimental group had better understanding on the hospital life than the booklet reading control group. The movie watching group had more satisfaction with the guide program than the booklet reading group. The understanding of the hospital life and satisfaction with the program had relevance. Conclusion: This study suggests that the in-patient guide movie would help the would-be in-patients understand and adapt to the hospital life better. Therefore, the in-patient guide movie is considered to be a useful medium to educate in-patients for their hospital life.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.1
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• pp.95-103
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• 2011

Robots in various types carry and assemble parts through repeatedly and accurately moving to stored locations by combining linear motions. And, linear systems are used in orthogonal axes of robots and driven via ball screws, such as 2-axis cartesian coordinate robot in this paper. This paper presents the effect of the linear motion guide that is used in $2^{nd}$ axis in 2-axis cartesian coordinate robot. Some simulation results show that the linear motion guide influence greatly in robot performance such as the nominal life of linear guide. When use LM guide that have capacity near in $2^{nd}$ axis, this paper show that the nominal life on LM block of $1^{st}$ axis increases 37.4% and that the specification of $2^{nd}$ axis LM guide influences greatly the nominal life of $1^{st}$ axis LM block.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.12
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• pp.963-970
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• 1989

The navigation problem for a mobile robot is investigated. Specifically, it is proposed that simple guide-marks be introduced and the navigation scheme be generated in conjunction with the guide-marks sensed through camera vision. For autonomous navigation, it was shown that a triple guide-mark system is more effective than a single guide-mark in estimating the position and orientation of mobile robot itself. The navigation system is tested via a mobile robot HERO-I equipped with a single camera in laboratory environment.

• Transactions of Materials Processing
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• v.9 no.2
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• pp.171-178
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• 2000

This paper is concerned with the optimization of the drive for linear-guide press which is one of mechanical presses. The design of linear-guide drive for a mechanical press is introduced and the drive for the linear-guide press is optimized for the improvement of load and velocity characteristics. As a result of optimization, the load capacity during stroke increases and the slide velocity decreases in working region, respectively. The new design could be suited to many applications in precision forming such as extrusion and the sheet metal-forming processes.

• Proceedings of the Safety Management and Science Conference
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• 2007.04a
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• pp.437-448
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• 2007

This paper introduce information technology of software process assessment. It consists of eight parts such as concepts and introductory guide, a reference model for processes and process capability, performing an assessment, guide to performing assessments, an assessment model and indicator guidance, guide to competency of assessors, guide for use in process improvement, and guide for use in determining supplier process capability.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.162-162
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• 2000

We describe a new optical-type guide sensor for AGV. It is robust the disturbance of the light. The developed optical-type guide sensor is very useful in the clean room environment where the light disturbance is very critical through the hole on the surface of the floor.

• Journal of Science Education
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• v.47 no.2
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• pp.117-126
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• 2023

In an elementary school science teacher's guide, the guide in details that can help elementary school teachers with difficulties when preparing and conducting science classes are essential. To gain insights into the development of the 2022 revised curriculum elementary school science teacher's guide, it is necessary to investigate the perceptions and needs of elementary school teacher's guide in details. In this study, we developed a questionnaire by analyzing the components and design of an elementary school science teacher's guide in details to explore elementary school teachers' perceptions and needs. For this purpose, we first investigated elementary school teachers' perceptions of their needs, satisfaction, and the utilization of each component of the current guide in details. Next, we investigated teachers' needs regarding the specific components and design of a guide. The findings were as follows. First, elementary school teachers were delighted with the components that help them prepare and conduct lessons. Second, elementary school teachers wanted an easy-to-read design with a layout that allowed them to see the components they needed for their lessons at a glance. In conclusion, the elementary school science teacher's guide in details to be readable and organized to provide at-a-glance information on lesson preparation, lesson flow, and teaching and learning materials needed for science teaching-learning. Based on the results of this study, new approaches and attempts should be made to develop a textbook that elementary school teachers can utilize in the future.

• The KSFM Journal of Fluid Machinery
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• v.17 no.5
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• pp.19-26
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• 2014

The cross flow turbine attracts more and more attention for its relatively wide operating range and simple structure. In this study, a novel type of micro cross flow turbine is developed for application to a step in an irrigational channel. The head of the turbine is only H=4.3m and the turbine inlet channel is open ducted type, which has barely been studied. The efficiency of the turbine with inlet open duct channel is relatively low. Therefore, a guide nozzle on the turbine inlet is attached to improve the performance of the turbine. The guide nozzle shapes are investigated to find the best shape for the turbine. The guide nozzle plays an important role on directing flow at the runner entry, and it also decreases the negative torque loss by reducing the pressure difference in Region 1. There is 12.5% of efficiency improvement by attaching a well shaped guide nozzle on the turbine inlet.