• Journal of Korean Ophthalmic Optics Society
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• v.8 no.1
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• pp.11-15
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• 2003

Purpose : The purpose of this study is to investigate the corneal topography changes as a result of near task in myopes and emmetropes. Methods : Thirty university students, aged from 18 to 24 years old, were randomly selected. They were divided into two refractive groups of fifteen each : myopia and emmetropia. The corneal topography of each subject was measured with the Eye-Sys Videokeratography system. Measurements were taken : before and after 30 minutes of near task (copy N10 text at 20 cm working distance). Both simulated keratometry and semi-meridian keratometric map program were used in the data analysis. Results : Our results reveal no significant changes in both simulated keratometry and semi-meridian presentation as a result of near task for both myopes and emmetropes, except a significant change (p<0.05) found at the flattest meridian of the central (3 mm) portion of the corneal topography after near task for emmetropes only. Conclusions : We conclude that the corneal topography, does not change significantly as a result of near task in both myopes and emmetropes.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.2
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• pp.85-92
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• 2003

In this paper, we propose a method to evaluate performances of mobile personal robots. A set of performance measures is proposed and the corresponding evaluation methods are developed. Different from industrial manipulators, personal robots need to be evaluated with its mobility, navigation, task and intelligent performance in environments where human beings exist. The proposed performance measures are composed of measures for mobility including vibration, repeatability, path accuracy and so on, as well as measures for navigation performance including wall following, overcoming doorsill, obstacle avoidance and localization. But task and intelligent behavior performances such as cleaning capability and high-level decision-making are not considered in this paper. To measure the proposed performances through a series of tests, we designed a test environment and developed measurement systems including a 3D Laser tracking system, a vision monitoring system and a vibration measurement system. We measured the proposed performances with a mobile robot to show the result as an example. The developed systems, which are installed at Korea Agency for Technology and Standards, are going to be used for many robot companies in Korea.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1527-1530
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• 1996

Telerobot system is being developed for the application to nuclear power plants by Korea Atomic Energy Research Institute. Human-machine interaction and interface are very important elements of telerobotic systems. The main purpose of this study is developing a control system based on 3-D graphic techniques for the easy user interface and realistic visual I information supply. This system possesses the abilities for (1) virtual work, environment modelling and simulation, (2) kinematic animation include redundant behavior (3) interfacing with a real robot system, (4) transformation between real and virtual mode within the same graphics system. This system is especially focused on enhancing the overall efficiency and reliably of nozzle dam installation task inside water chamber of steam generator in nuclear power plant.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.210-220
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• 2003

This work presents a method of point to surface assignment fur 3D metrology of solder pastes on PCB. A bounding box enclosing the solder paste tightly on all sides is introduced to avoid incorrect assignment. The shape of bounding box fur solder paste brick is variable according to geometry of measured points. The surface geometry of bounding box is obtained by using five peaks selected in the histogram of normalized gradient vectors. By using the bounding box enclosing the solder pastes, the task of point-to-surface assignment has been successfully conducted, then geometrical features are obtained through the task of surface fitting.

• The Journal of Information Systems
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• v.31 no.2
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• pp.197-216
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• 2022

Purpose In this study, in order to understand the effects of NTIS users' behavioral scientific behaviors and determinants, an integrated model of the UTAUT(Unified Theory of Acceptance and Use of Technology) model and TTF(Task-Technology Fit) model, which are frequently used MIS field, was presented and empirical analysis was conducted. Design/methodology/approach In this study, an online survey was conducted on researchers from organizations carrying out national R&D projects, institutions, universities, and dedicated management institutions and the collected data verified hypotheses established using the SPSS 25.0 statistical package and structural equation model using AMOS. Findings The results showed that NTIS users' business activities had a positive(+) effect on task-technology fit and task-technology fit had a positive(+) effect on performance expectation, effort expectation, and continuous intention-to-use intention. In addition, the performance expectation, effort expectation, and promotion conditions presented in research model had a positive(+) effect on the continuous intention-to-use. The research results derived through this study are expected to contribute substantially to subsequent research in the field related to information sharing platforms.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.10
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• pp.839-846
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• 2016

Bin picking is a task of picking a small object from a bin. For accurate bin picking, the 3D pose information, position, and orientation of a small object is required because the object is mixed with other objects of the same type in the bin. Using this 3D pose information, a robotic gripper can pick an object using exact distance and orientation measurements. In this paper, we propose a 3D vision technique for accurate measurement of 3D position and orientation of small objects, on which a paper label is stuck to the surface. We use a maximally stable extremal regions (MSERs) algorithm to detect the label areas in a left bin image acquired from a stereo camera. In each label area, image features are detected and their correlation with a right image is determined by a stereo vision technique. Then, the 3D position and orientation of the objects are measured accurately using a transformation from the camera coordinate system to the new label coordinate system. For stable measurement during a bin picking task, the pose information is filtered by averaging at fixed time intervals. Our experimental results indicate that the proposed technique yields pose accuracy between 0.4~0.5mm in positional measurements and $0.2-0.6^{\circ}$ in angle measurements.

• Korean Journal of Computational Design and Engineering
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• v.21 no.1
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• pp.20-30
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• 2016

Recently immersive virtual reality (VR) becomes popular due to the advanced development of I/O interfaces and related SWs for effectively constructing VR environments. In particular, natural and intuitive manipulation of 3D virtual objects is still considered as one of the most important user interaction issues. This paper presents a comparative study on the manipulation and interaction of 3D virtual objects using different interfaces and interactions in three VR environments. The comparative study includes both quantitative and qualitative aspects. Three different experimental setups are 1) typical desktop-based VR using mouse and keyboard, 2) hand gesture-supported desktop VR using a Leap Motion sensor, and 3) immersive VR by wearing an HMD with hand gesture interaction using a Leap Motion sensor. In the desktop VR with hand gestures, the Leap Motion sensor is put on the desk. On the other hand, in the immersive VR, the sensor is mounted on the HMD so that the user can manipulate virtual objects in the front of the HMD. For the quantitative analysis, a task completion time and success rate were measured. Experimental tasks require complex 3D transformation such as simultaneous 3D translation and 3D rotation. For the qualitative analysis, various factors relating to user experience such as ease of use, natural interaction, and stressfulness were evaluated. The qualitative and quantitative analyses show that the immersive VR with the natural hand gesture provides more intuitive and natural interactions, supports fast and effective performance on task completion, but causes stressful condition.

• Journal of Korea Game Society
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• v.8 no.1
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• pp.91-101
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• 2008

Most designers use professional 3D animation tools such as 3DS MAX to manually create animation. This manual method requires a great deal of time and efforts, and does not allow animation characters to interact with one another. In this paper, we design an AI middleware of form as 3DS MAX plug-in to solve these issues. We present an AI expression structure and internal processing method for this middleware, and the method for creating AI character's structure. It creates AI character's structure by drawing figures and lines for representing AI elements. For experiment, we have produced same animations with the traditional method and our method, and measured the task volume in both methods. This result verifies that the task volume is similar or higher than the traditional method in small-scale tasks, but up to 43% of the task volume is reduced in large-scale tasks. Using the method proposed in this paper, we see that characters in an animation interact each other, and task volume in large-scale tasks are reduced.

• Safety and Health at Work
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• v.10 no.3
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• pp.321-326
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• 2019

Background: Performing cognitive tasks and muscular fatigue have been shown to increase muscle activity of the lower extremity during quiet standing. A common intervention to reduce muscular fatigue is to provide a softer shoe-surface interface. However, little is known regarding how muscle activity is affected by softer shoe-surface interfaces during static standing. The purpose of this study was to assess lower extremity muscular activity during erect standing on three different standing surfaces, before and after an acute workload and during cognitive tasks. Methods: Surface electromyography was collected on ankle dorsiflexors and plantarflexors, and knee flexors and extensors of fifteen male participants. Dependent electromyography variables of mean, peak, root mean square, and cocontraction index were calculated and analyzed with a $2{\times}2{\times}3$ within-subject repeated measures analysis of variance. Results: Pre-workload muscle activity did not differ between surfaces and cognitive task conditions. However, greater muscle activity during post-workload balance assessment was found, specifically during the cognitive task. Cognitive task errors did not differ between surface and workload. Conclusions: The cognitive task after workload increased lower extremity muscular activity compared to quite standing, irrespective of the surface condition, suggesting an increased demand was placed on the postural control system as the result of both fatigue and cognitive task.

• Korean Journal of Cognitive Science
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• v.25 no.4
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• pp.385-416
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• 2014

In this study, memory for emotional words was compared between extraverts and introverts, employing signal detection analysis to distinguish differences in discriminative memory and response bias. Subjects were presented with a study list of emotional words in an encoding session, followed by a recognition session. Effects of task difficulty were examined by varying the nature of the encoding task and the intervals between study and test. For an easy task, with a retention interval of 5 minutes (Study I), introverts exhibited better memory (i.e., higher d') than extraverts, particularly for low-frequency words, and response biases did not differ between these two groups. For a difficult task, with a one-month retention period (Study II), performance was poor overall, and only high-frequency words were remembered; also extraverts adopted a more liberal criterion for 'old' responses (i.e., more hits and more false alarms) for positive emotional-valence words. These results suggest that as task difficulty drives down performance, effects of internal control processes become more apparent, revealing differences in response biases for positive words between extraverts and introverts. These results show that extraversion can distort memory performance for words, depending on their emotional valence.