• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.610-615
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• 2005

Visual servoing is the fusion of results from many elemental areas including high-speed image processing, kinematics, dynamics, control theory, and real-time computing. It has much in common with research into active vision and structure from motion, but is quite different from the often described use of vision in hierarchical task-level robot control systems. We present a new approach to visual feedback control using image-based visual servoing with the stereo vision in this paper. In order to control the position and orientation of a robot with respect to an object, a new technique is proposed using a binocular stereo vision. The stereo vision enables us to calculate an exact image Jacobian not only at around a desired location but also at the other locations. The suggested technique can guide a robot manipulator to the desired location without giving such priori knowledge as the relative distance to the desired location or the model of an object even if the initial positioning error is large. This paper describes a model of stereo vision and how to generate feedback commands. The performance of the proposed visual servoing system is illustrated by the simulation and experimental results and compared with the case of conventional method for dual-arm robot made in Samsung Electronics Co., Ltd.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.2
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• pp.154-161
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• 1998

Prototypes of a design are always needed for the purpose of visualization and evaluation in the aspect of manufacturability functionality, and aesthetic appearance. Since the prototyping process requires a significant amount of cost and time, various rapid prototyping processes are recently being introduced in the process. However, it is usually necessary for a part built up by a rapid prototyping system to be refined by a post-processing process, in which the stair steps on the surfaces, the support structures (if they exist), and the unprocessed material are eliminated. This post-processing is usually done manually and is a time-consuming task. Especially, eliminating the trapped volumes, the volume of the unprocessed material entrapped by the solidified portion, is sometimes impossible in some processes. This study provides a designer with a tool to detect the existence and to calculate the quantity of the trapped volumes at the given build-up direction, so that the proper build-up direction is chosen or the part is built by pieces to avoid the problems caused by the trapped volumes in advance. Since the proposed algorithm can efficiently calculate the amount of the trapped volumes at any build-up direction, it has the potential of such application as optimizing the build-up direction to minimize the trapped volumes.

• Journal of The Korean Association For Science Education
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• v.16 no.2
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• pp.217-225
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• 1996

Science-related attitudes, perceptions of science classroom environments, and their relationships were investigated for a sample of 535 primary and secondary school students. Two scales of the Test of Science-Related Attitudes and five scales of the Classroom Environment Scale(CES) were administered. Students' perceptions of preferred science classroom environments were also investigated using the same scales of the CES and compared with those of actual classroom environments. The results indicated the primary school students had the most positive attitudes on Enjoyment of Science Lesson and Career Interest in Science. They also had the highest scores on perceptions of actual classroom environments, while the high school students had the lowest scores. Regarding the relationships between science-related attitudes and perceptions of classroom environments, multiple correlations for the five scales of the CES were found to be significant(p<01). The scores of four scales-Involvement, Teacher Support, Order and Organization, Rule Clarity-are significantly correlated with the scores of Enjoyment of Science Lesson. Students' perceptions of preferred classroom environments on the four scales of the CES are significantly higher than those in actual environments. However, students' perceptions of actual environments on Task Orientation are similar to those of preferred environments, and are not significantly correlated with Enjoyment of Science Lesson. Educational implications are discussed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.5
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• pp.1002-1012
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• 2003

An algorithm is suggested for collision avoidance of two-arm robot manipulator using redundancy. End-effectors of each redundant arm should move along each prescribed straight path to complete the given task, while avoiding collision with each other. Self-motion, considered as motion of each axis not to change the position and orientation of end-effector, is utilized in order to solve this problem. At each sampling time, self-motion is executed with the view to making farther between the links of each arm. Simulation results for two-arm robot manipulator, which has 9-d.o.f. respectively, are illustrated to show the performance of the algorithm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.5
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• pp.891-898
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• 2001

This paper develops a master manipulator which can reflect a force from a slave manipulator effectively. It many have a big workspace, can represent a human operators manipulation perfectly, and is composed of a position control part, an orientation control part and an end effector control part. This paper also develops a graphic simulator using the Visual C++ and OpenGL in the Window operating system. It can be used to make a virtual slave manipulator and set a virtual working environment, and provide a visual information from a desired view point. A virtual teleoperation system is developed by connecting the developed master manipulator to the graphic simulator using an interfacing hardware bilaterally. It is used for performing a virtual object exploration experiment. In the experiment, two virtual objects are used. They are virtual wall and virtual hexahedron which have 0.7N/mm and 2.2 N/mm stiffness respectively. The experiments are performed under six different working conditions. The experiment results will show the effectiveness of the reflected force from the slave manipulator for improving the efficiency and stability of the teleoperation task.

• Journal of Power Electronics
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• v.6 no.1
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• pp.18-28
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• 2006

The Electric Power Subsystem (EPS) is one of the most critical systems on any satellite because nearly every subsystem requires power. This makes the choice of power systems the most important task facing satellite designers. The main purpose of the Satellite EPS is to provide continuous, regulated and conditioned power to all the satellite subsystems. It has to withstand radiation, thermal cycling and vacuums in hostile space environments, as well as subsystem degradation over time. The EPS power characteristics are determined by both the parameters of the system itself and by the satellite orbit. After satellite separation from the launch vehicle (LV) to its orbit, in almost all situations, the satellite subsystems (attitude determination and control, communication and onboard computer and data handling (OBC&DH)), take their needed power from a storage battery (SB) and solar arrays (SA) besides the consumed power in the EPS management device. At this point (separation point, detumbling mode), the satellite's angular motion is high and the orientation of the solar arrays, with respect to the Sun, will change in a non-uniform way, so the amount of power generated by the solar arrays will be affected. The objective of this research is to select satellite EPS component types, to estimate solar array illumination parameters and to determine the efficiency of solar arrays during both detumbling and normal operation modes.

• Korea Journal of Hospital Management
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• v.16 no.1
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• pp.124-141
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• 2011

The purpose of this study was to analyze of hospital administrator based on the DACUM(Developing A Curriculum) method. The contents of this study were to extract the duties, tasks consisting of job of hospital administrator and to investigate levels of importance, difficulty, frequency and entry level on each task, and to make out a job model of hospital administrator. A DACUM committee was composed to analyze job of hospital administrator and the committee members were total 9, a facilitator, 7 hospital administrator and a recorder. The major findings of this study were as the followings; first, duties in job of hospital administrator were total 13, which were organization of hospital administration affairs, health insurance review & assessment, general affairs, personnel management, hospital planning & management, medical quality improvement, hospital financial affairs, logistics management, facilities management, computerized system management, education & study supports, medical staffs' perceptions of service quality both directly and indirectly through their perceptions of patient orientation. These findings implied that HPWS would be a way of survival in drastically changing hospital environments.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.5
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• pp.331-341
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• 2019

With the popularity of sensor-rich environments, smartphones have become one of the major platforms for obtaining and sharing information. Since it is difficult to utilize GNSS (Global Navigation Satellite System) inside the area with many buildings, the localization of smartphone in this case is considered as a challenging task. To resolve problem of localization using smartphone a four step image-based localization method and procedure is proposed. To improve the localization accuracy of smartphone datasets, MMS (Mobile Mapping System) and Google Street View were utilized. In our approach first, the searching for candidate matching image is performed by the query image of smartphone's using GNSS observation. Second, the SURF (Speed-Up Robust Features) image matching between the smartphone image and reference dataset is done and the wrong matching points are eliminated. Third, the geometric transformation is performed using the matching points with 2D affine transformation. Finally, the smartphone location and attitude estimation are done by PnP (Perspective-n-Point) algorithm. The location of smartphone GNSS observation is improved from the original 10.204m to a mean error of 3.575m. The attitude estimation is lower than 25 degrees from the 92.4% of the adjsuted images with an average of 5.1973 degrees.

• The Journal of Engineering Geology
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• v.31 no.4
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• pp.463-478
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• 2021

The subjects of the study are the sedimentary rock slope of the Mesozoic Gyeongsang Supergroup, which has a high risk of failure. The orientation of the slope-face represents a variety of changing characteristics. The rocks of the slope shall be sandstone, siltstone and dacite, and discontinuities shall develop beddings, shear joints, extension joints, and dacite dyke boundary planes. The type and scale of failure varies depending on the type of rock and the strike/dip of the discontinuities, but the toppling failure prevails. Based on the face-mapping data, SMR, physical and mechanical testing of rocks, analysis and review of the stereonet projections and the critical equilibrium analysis, all four representative sections required a countermeasure method because the acceptable safety factor during dry and rainy seasons were far below Fs = 1.5 and Fs = 1.2. After applying the countermeasure method, both the dry and wet conditions of the slope exceeded the allowable safety factor. In particular, the face-mapping data of the slope-face, the geological cross-sections of several representative sections perpendicular to the slope-face, and the critical equilibrium analysis and the presentation of countermeasure methods that have been reviewed based on them are expected to be reasonable tools for the slope stability. In addition, it will be possible to use it as basic data for performance evaluation for slope maintenance.

• The Journal of the Korea Contents Association
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• v.12 no.5
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• pp.541-552
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• 2012

The purpose of the study was to investigate the effects of On-Line Community Assisted Team Learning (OCATL) activities on academic achievement and team member's Shared Mental Model(SMM) subscale scores. Two studies were conducted over two semesters in different universities. The first study was aimed at examining the effects of OCATL on university students' academic achievement using pre- and post- experimental design. For this experiment, 133 university students composed of 80 male and 53 female students from 13 colleges participated. The OCATL activities included the orientation of OCATL, seminar on collaborative learning, on-line community assisted team learning with sixteen hour participation during one semester and a final report (or a term paper). To measure these students' academic achievement, their pre- and post-semester's GPA were compared. The results of paired t-test revealed a significant difference in academic achievement (p<.05). The second study was designed to compare the scores of SMM subscales of the experimental group with the OCATL activities and those of the control group without using OCATL activities. The data was collected using the scale of Shared Mental Model(SMM)-short version developed by Johnson in 2011[18]. For this study, 74 participants from 10 teams served as an experimental group and 15 teams which were not exposed to OCATL activities served as a control group. The MANOVA results showed that SMM subscores of two groups measured after the experiment were statistically significantly different: The experimental group with the OCATL activities showed high scores on general task and team knowledge, general task and communication skills, attitudes toward team and task, team dynamics and interactions, team resources and working environment, and satisfaction with the team.