• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.12
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• pp.1-8
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• 1996

In this paper, we propose a hybrid blind equalizer with TEA and SG (stop & Go) algorithm with switching point a 0 dB of MSE value for improvement of convergence performance, where TEA is used initially to open the eye and then SG algorithm as rapid convergence is employed. The switching point is selected at the point of 0 dB MSE level because of settling the coefficients of blind equalier. As a result of computer simulatons for 8-PAM in the non-minimum phase channel, the proposed algorithm has better convergence speed as 3,500 ~ 4,500 iterations and has better MsE about 3 ~ 6 dB than those of original TEA. Also, computational cost of proposed algorithm is reduced as 5 ~ 16% than that of original TEA. and, the proposed algorithm has better convergence than SG algorithm as 8,500 ~ 17,500 iteratins but, the MSE is similar to original SG.

• Progress in Medical Physics
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• v.18 no.1
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• pp.1-6
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• 2007

A system to non-invasively fix and monitor eye by a head mounted display (HMD) with a CCD camera for stereotactic radiotherapy (SRS) of uveal melanoma has been developed and implemented clinically. The eye fixing and monitoring system consists of a HMD showing patient a screen for fixing eyeball, a CCD camera monitoring patient's eyeball, and an immobilization mask. At flrst, patient's head was immobilized with a mask. Then, patient was Instructed to wear HMD, to which CCD camera was attached, on the mask and see the given reference point on its screen. While patient stared at the given point in order to fix eyeball, the camera monitored Its motion. Four volunteers and one patient of uveal melanoma for SRS came into this study. For the volunteers, setup errors and the motion of eyeball were analyzed. For the patient, CT scans were peformed, with patient's wearing HMD and fixing the eye to the given point. To treat patient under the same condition, daily CT scans were also peformed before every treatment and the motion of lens was compared to the planning CT Setup errors for four volunteers were within 1mm and the motion of eyeball was fixed within the clinically acceptable ranges. For the patient with uveal melanoma, the motion of lens was fixed within 2mm from daily CT scans. An eye fixing and monitoring system allowed Immobilizing patient as well as monitoring eyeball and was successfully implemented in the treatment of uveal melanoma for SRS.

• Smart Media Journal
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• v.5 no.2
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• pp.33-41
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• 2016

FPS Games are usually centered on a combat game play where the player plays through a first-person perspective as the in-game character, in order to strike the opponent in accordance with each level's objective. In such type of game play, the decision making that leads the player to take certain actions is carried out based on the player's visual cognitive information, and information collected both directly/indirectly via previous game play experiences. Particularly in the case of a FPS game where the mutual interaction between the player and each game level is the key, an analysis of a FPS game player's visual cognitive information can provide intelligence which can help design or adjust structures of a game level. For this thesis, a sample group has been collected and divided into a novice group and an expert group based on their level of experience with FPS games. Then, using eye-tracking equipments, the point of gaze of players in each group were recorded whilst they were playing levels of a well-known FPS title. The point of gaze in the moment the player starts to take actions -right before/after the start of a combat- was recorded in 500 play videos, and as a result each group's intrinsic pattern of gaze could be identified. Through these results, the author plans to develop a methodology that can enhance the difficulty setting and the playability of FPS game levels.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.6
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• pp.403-410
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• 2016

This paper proposes a robust image-based visual servoing scheme using a nonlinear observer for a monocular eye-in-hand manipulator. The proposed control method is divided into a range estimation phase and a target-tracking phase. In the range estimation phase, the range from the camera to the target is estimated under the non-moving target condition to solve the uncertainty of an interaction matrix. Then, in the target-tracking phase, the feature point uncertainty caused by the unknown motion of the target is estimated and feature point errors converge sufficiently near to zero through compensation for the feature point uncertainty.

• Journal of Preventive Medicine and Public Health
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• v.37 no.2
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• pp.111-119
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• 2004

Purpose : To identify those factors influencing the post-operative satisfaction in myopia patients receiving laser in situ keratomileusis (LASIK) Methods : This study included 288 consecutive patients who received LASIK between July and December 2001 from two eye clinics located in Seoul and Pusan. Factors that were considered to influence post-operative satisfaction included pre-operative baseline characteristics, pre-operative expectation for treatment outcomes, and treatment outcomes. Before undergoing LASIK, study subjects were asked to rate the degree of their expectation for the improvement of visual functions and symptoms after LASIK on a 5-point Likert-type scale: where 1 referred to 'somewhat worse,' 2 to 'no change,' 3 to 'somewhat improved,' 4 to 'improved,' and 5 to 'very improved.' Self-administered questionnaire was used to evaluate baseline visual functions and symptoms on a 5-point scale before LASIK. At 6 months after LASIK, the evaluation was repeated to measure treatment outcomes in terms of the difference in the score before and after LASIK. Post-operative satisfaction was also measured at 6 months on a 5-point scale. Multiple regression analysis was performed to examine the independent relationship between influencing factors and postoperative satisfaction. Results : A total of 171 patients (59.4%) participated in the 6-month follow-up investigation. The average expectation scores for the improvement in visual functions and symptoms were 3.8 and 3.4, respectively. The average score for the 7 questions assessing satisfaction was 4.0. The results of the regression analysis showed that the post-operative satisfaction increased with improvement in the visual function ($\beta$=0.16, p<0.05) and symptoms ($\beta$=0.25, p<0.05), the degree of preoperative refractive error ($\beta$ =0.26-0.67, p<0.05) and in male patients ($\beta$=0.31, p<0.1). The pre-operative expectation was not a statistically significant factor in explaining postoperative satisfaction in the regression model. Conclusion : The finding from this study was that patients with very severe myopia tended to be more satisfied with the treatment than those with mild myopia, which implies that LASIK can be more beneficial to those suffering from a severe visual condition. Patient satisfaction was also significantly affected by the treatment outcomes experienced after LASIK. This suggests that improving the clinical outcome is the most fundamental requirement for the improvement of patient satisfaction.

• Smart Media Journal
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• v.13 no.4
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• pp.94-103
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• 2024

The eyeball input system is a text input system designed based on 'eye tracking technology' and 'virtual keyboard character-input technology'. The current virtual keyboard structure used is a rectangular QWERTY array optimized for a multi-input method that simultaneously utilizes all 10 fingers on both hands. However, since 'eye-tracking technology' is a single-input method that relies solely on eye movement, requiring only one focal point for input, problems arise when used in conjunction with a rectangular virtual keyboard structure designed for multi-input method. To solve this problem, first of all, previous studies on the shape, type, and movement of muscles connected to the eyeball were investigated. Through the investigation, it was identified that the principle of eye movement occurs in a circle rather than in a straight line. This study, therefore, proposes a new key arrangement wherein the keys are arranged in a circular structure suitable for rotational motion rather than the key arrangement of the current virtual keyboard which is arranged in a rectangular structure and optimized for both-hand input. In addition, compared to the existing rectangular key arrangement, a performance verification experiment was conducted on the circular key arrangement, and through the experiment, it was confirmed that the circular arrangement would be a good replacement for the rectangular arrangement for the virtual keyboard.

• Journal of Environmental Science International
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• v.13 no.6
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• pp.497-503
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• 2004

In this research, we have performed a T-test to see how the relationship between dependent variable or visual point level and independent variable or visual quantity is in order to clear up the correlation between pattern of visual point and visual quantity by the constituents of a view from a different visual point level and the results are as follows: 1) In case of the character of Mt. Uam landscape of the city, Uamsan is set as a fixed point and about a direction of view(D), the north is a datum point from which the range of direction is distributed within 1800 westwardly and the visual range(R) is also within 2000m. An elevation is an average of 7.40 and the average story of the buildings is 3.85. Here the height of a story is about 4m so the average of the visual point difference is estimated at 15.4m. 2) The type of visual point is divided into the intersection group and the front of the highly used public buildings group. Double intersection types account for about 78.80%(52 spots) which forms a majority part of LCP. 3) The analysis of the difference of visual point level divided by eye level and that of the top of the buildings has been proved that there's a sharp difference resulted from t-test at 1 % significant level. The significant difference of elevation from height difference(l5.93m), however, has not been shown. 4) From the result of T-test about visual quantity by the elements of a view from a different visual point level, the visual quantity of mountain(VQM), sky(VQS), ground(VQG) is significant at about 1% each and that of building(VQB) is at about 5%. The difference in visual quantity of a mountain by the visual point level is at about 4% which can meet a marginal level of LCP necessary for evaluation of mountainscape.

• The Journal of Korean Academy of Prosthodontics
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• v.22 no.1
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• pp.72-78
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• 1984

The notion that the axis of the shaft of the articulator must coincide the patient's mandibular transverse axis tells us the importance of locating the axis precisely. When using kinematic axis to transfer a cast to an articulator, the anatomic asymmetry of the contralateral points will result in certain distortion when the axis transferred to an articulator where the mechanical axis produces symmetry. In this study, after locating the true hinge axis point with Denar hinge axis locator, the discrepancies between true hinge axis point and arbitrary hinge axis point that was 13mm anterior from the posterior margin of center of trangus to the outer canthus of eye were measured. And the discrepancies between left and right true hinge axis point in the superoinferior and anteroposterior directions were measured. For this study, 20 dental students who have no missing teeth and no difficulties of mandibular movement were selected. Upper and lower cast of subjects were mounted on Denar Mark II articulator uisng Denar Slidematic face-bow and centric relation record for the measurement of discrepancies between left and right true hinge axis points. The results obtained as follows. 1. The mean distance from the arbitrary hinge axis point to the true hinge axis point was as follows. Right: horizontal distance; 1.99mm, vertical distance; 2.12mm, linear distance; 3.36 mm. Left: horizontal distance; 1.39mm, vertical distance; 2.06mm, linear distance; 2.09mm. Total: horizontal distance; 1.69mm, vertical distance; 2.09mm linear distance; 3.06 mm. 2. The 87.5% of true hinge axis points were within 5mm of the arbitrary hinge axis point. 3. The mean discrepancies between the right and left hinge axis point were 2.92mm in superoinferior direction and 4.74mm in anteroposterior direction. 4. When transferring the axis to the articulator, anatomic asymmetry between right: and left axis point produces in dislocation of cast on the articulator, and undesirable shift in esthetic tooth position will be resulted.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.477-480
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• 1989

In this paper, we introduce the three-dimensional Korean character display by using 2D fonts and character depth. Character segments are designed by the set of vertex at run time. Character depth is applied for 3D visualization. And, the variation of eye-point and distance of object is used for 3D character animation.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.3
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• pp.59-66
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• 1995

In this study through a series of the experiments, 1) the preferable luminance values of the CRT screens, 2) the preferable luminance ratios between the CRT screens and its surrounding surfaces are determined. The results are evaluated by the level of satisfaction, and re-examined by the work performance (number of types, rate of errors) and the level of eye fatique (number of blinks, near point distance)