• Journal of radiological science and technology
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• v.41 no.5
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• pp.421-426
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• 2018

Unlike the traditional Radiological examinations, Magnetic Resonance Imaging (MRI) does not cause any harm and high levels of Radiation to the human body. Furthermore, MRI is widely used owing to its ability to adapt to different situations. However, the MRI equipment creates noises from its mechanical parts, and its magnetic bore structure can cause anxiety and claustrophobia in patients. To relieve claustrophobia, commercial refraction glasses were provided to the participants in this study, and the changes in anxiety and claustrophobia were measured. The participants were 30 volunteers with claustrophobia. To measure anxiety, the participants were asked to answer a Visual Analogue Scale (VAS) questionnaire. The physical markers of discomfort included perspiration on the forehead or hands (46.7%), mild frowning (30.3%), and leg shaking (40.1%). The subjective markers of discomfort included dizziness (2.85% in the men and 1.75% in the women). Although fear and anxiety levels were observed to be higher in the men, the difference was not significant. Hence, it was determined that both men and women felt discomfort (p >0.5). The fear coefficient was observed to decrease from 7.67 prior to wearing refraction glasses to 2.42 after wearing refraction glasses (p<0.000). In addition, use of refraction glass decreased MRI aversion from 1.97 to 1.03 (p<0.000). It can be inferred that refraction glasses are beneficial to patients undergoing MRI.

• Journal of the Korea Safety Management & Science
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• v.13 no.3
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• pp.29-35
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• 2011

Safety and health related information for the proper use and handling of pesticides is usually printed on the surface of the pesticide products (bottle type or bag type) in the form of texts. But, the guidelines or standards for the appropriate presentation of the texts for the pesticide products are most vague or not practical. Thus, this study aimed to provide the preliminary guidelines for the text sizes based on the legibility experiments. Total twenty subjects from two age groups (young: n=10, old: n=10, five males and five females in each group) participated in the experiment. First, subjects read the text cards presented in the distance of 50cm from the eyes of the subjects. Eight different text card sets were prepared for different font type(thick gothic-type and fine gothic-type), thickness of font(plain and bold), and number of syllables (2 and 3 syllables). When subjects read the cards, the correctness of reading (correct or wrong) was recorded and the degree of discomfort (from 1: no discomfort at all to 4: can't read at all) was also evaluated for all the text sizes. Results showed that the character size should be 4 pt or larger for the young subjects to read at least one word correctly in all the text conditions. For the old subjects to read at least one word correctly, the character size should be five pt or larder. The average of the minimum character sizes for 100% correct answer is 6.1 pt for young subjects and 10.5 pt for old subjects, respectively.

• Journal of Korean Medicine Rehabilitation
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• v.20 no.3
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• pp.37-60
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• 2010

Objectives : The purpose of this study was to investigate the relationship between masseter and cervical muscle activity and temporomandibular disorder in female office workers. Methods : Experimental group of 24 healthy subjects complained of temporomandibular joint related to computer use which lasted more than 3 months in the past year and was present in the past 7 days as well as on the day of test. Control group of 20 healthy subjects had no complaints of minimal discomfort on the day of test, and had no discomfort in the past 7 days. If they had reported discomfort in the past 12 months, it was of a short duration(<3 months) and resolved at least 3 months prior to participation. Outcomes were assessed by meridian-electromyography(MEMG), whole spin x-ray, mandibular function impairment questionnaire(MFIQ), neck disability index(NDI), visual analog scale(VAS), Beck depression inventory(BDI), stress reaction inventory(SRI) and Holmes & Rahe social readjustment rating scale(SRRS). Results : The contraction power of masseter muscle, upper trapezius, sternocleido-mastoid muscle and erector spinae by MEMG was significantly higher in the experimental group. The muscle fatigue of masseter muscle and sternodeido-mastoid muscle by MEMG was significantly higher in the experimental group. SRI was significantly higher in experimental group. There was no significant difference between two groups in the Jackson's angle, Cobb's method and cranio-cervical posture. Conclusions : The results suggest that temporomandibular disorder related mental stress but physical stress does not change cervical structure significantly.

• Archives of Craniofacial Surgery
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• v.12 no.1
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• pp.17-21
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• 2011

Purpose: It is difficult to objectively evaluate the outcomes of plastic surgical procedures. The combination of aesthetic and medical factors makes outcome quantification difficult. In this study, fracture reduction accuracy was objectively evaluated in patients with zygomatic complex fractures. Patients satisfaction with the accuracy was also examined. In addition, the patients' overall satisfaction and discomfort due to complications were analyzed. Methods: Eighty-five patients who had surgeries via bicoronal incision for zygomatic complex fracture from March 2006 to December 2009 were included in this study. Two plastic surgeons evaluated the accuracy of the fracture reduction with postoperative computed tomography. A survey questionnaire was administered to evaluate the patients' overall satisfaction and the impact of symptoms associated with the procedure on the patients' daily lives. Results: The overall patient satisfaction rate was $82.1{\pm}10.9%$ (range, 45~100%). The level of deformation was $6.7{\pm}10.9%$, the levels of discomfort in daily life due to pain, paresthesia, scar, and facial palsy were $8.5{\pm}13.2%$, $5.8{\pm}8.9%$, $4.4{\pm}9.9%$, and $1.9{\pm}9.2%$, respectively. According to the visual analogue scale, paresthesia was found to be the most frequent symptom (43.5%), and pain was the most troublesome symptom. Conclusion: The use of bicoronal incision for treating zygomatic complex fractures can cause various complications due to wide incision and dissection. However, this technique can provide optimized reduction and rigid fixation. Most of these postoperative complications can cause significant discomfort in the patient. It is thought that the use of correct surgical technique and the accurate knowledge of craniofacial anatomy will result in a reduction of complications and significantly increase patient satisfaction.

• Journal of dental hygiene science
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• v.23 no.2
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• pp.176-184
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• 2023

Background: Recently, a piezoelectric ultrasonic scaler based on a feedback control mechanism was introduced for pain relief. This study aimed to investigate the effects of a new ultrasonic scaler in reducing pain and discomfort in adults. Methods: A newly introduced ultrasonic scaler (Master 700^®) was used as the test device and a conventional ultrasonic scaler device (PIEZON^®) was used as the control device. Forty-one healthy adults visited the dental clinic for dental scaling but did not undergo scaling or periodontal treatment within 6 months. Intraoral examinations were performed before scaling and 3 months later; before scaling, both devices were randomly assigned on the left or right side of each dentition (split-mouth model) and scaling was performed by a registered dental hygienist. The levels of pain and discomfort during scaling were evaluated subjectively and objectively using the visual analog scale (VAS) and physiological monitoring of the heart rate (HR), respectively. Time was measured for each device. Results: All clinical indicators, except bleeding on probing, significantly improved with both devices. The treatment times were 7 minutes, 13 minutes (control) and 6 minutes, 59 minutes (test). VAS scores for pain were 4.89±2.12 (control) and 4.58±2.77 (test) points out of 10; for noise, these were 4.68±2.33 (control) and 4.55±2.55 (test), and for vibration, the values were 4.26±2.0 (control) and 4.18±2.48 (test). HR averages were 72.34±3.39 (control) and 75.97±9.78 (test) beats/min. No statistically significant differences were observed between the devices. Conclusion:The pain, discomfort levels, and scaling time of the new piezoelectric ultrasonic scaler did not differ from those of the conventional device. Further research and development are necessary for more prominent pain-relief effects of scaling devices.

• Science of Emotion and Sensibility
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• v.16 no.1
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• pp.29-42
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• 2013

In this paper, we analyze the effect of the depth perception, volume perception and visual discomfort according to the change of the quality of the depth image and the depth of the major object. For the analysis, a 2D image was converted to eighteen 3D images using depth images generated based on the different depth position of a major object and background, which were represented in three detail levels. The subjective test was carried out using eighteen 3D images so that the degrees of the depth perception, volume perception and visual discomfort recognized by the subjects were investigated according to the change in the depth position of the major object and the quality of depth map. The absolute depth position of a major object and the relative depth difference between background and the major object were adjusted in three levels, respectively. The details of the depth map was also represented in three levels. Experimental results showed that the quality of the depth image differently affected the depth perception, volume perception and visual discomfort according to the absolute and relative depth position of the major object. In the case of the cardboard depth image, it severely damaged the volume perception regardless of the depth position of the major object. Especially, the depth perception was also more severely deteriorated by the cardboard depth image as the major object was located inside the screen than outside the screen. Furthermore, the subjects did not felt the difference of the depth perception, volume perception and visual comport from the 3D images generated by the detail depth map and by the rough depth map. As a result, it was analyzed that the excessively detail depth map was not necessary for enhancement of the stereoscopic perception in the 2D-to-3D conversion.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.2
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• pp.127-135
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• 2016

Purpose: The present study was aimed to investigate the effect of excessive near work by using a smartphone on subjective symptoms and accommodative and convergent function in their 40s. Methods: A total of 40 subjects(male, 10; female, 30; age, $43{\pm}7.2year$) in their 40s who have monocular and binocular visual acuities of 0.8 and 1.0, respectively, were divided into presbyopia group and non-presbyopia group. The subjects were asked to watch a movie on the screen of smartphone for 30 minutes. Their accommodative amplitude and facility, and relative accommodation were measured and compared before and after the use of smartphone. Changes in fusional vergence and near heterophoria by using smartphone were also evaluated. Furthermore, the change of subjective symptoms was surveyed using a questionnaire. Results: The presbyopia in mid-40s reported discomfort in an order of asthenopia, blur and dryness after the use of smartphone. Accommodative function and non-strabismic binocular function were generally decreased. Accommodative functions such as monocular accommodative amplitude, and relative accommodation were significantly decreased after smartphone use, and the change of phoria was observed as a result of decreased convergence and divergence. Negative fusional vergence was also significantly reduced. On the other hand, non-presbyopia in mid-40s reported discomfort in an order of asthenopia, dryness and blur, and only accommodative amplitude among the accommodative functions was significantly reduced. Significant reduction of negative fusional vergence was also observed. Conclusion: From the results, it was confirmed that the subjective discomfort of mid-40s after smarphone use might be related to whether presbyopia or not. It was due to not only the reduction of accommodative function but also the overall deterioration of visual function including heterophoria and fusional vergence. Therefore, it suggests that the accurate determination of the cause based on the overall visual functional tests such as heterophoria, fusional vergence as well as the decrease of accommodation due to the aging may be necessary when the mid-40s feels discomfortable symptoms by near work.

• Journal of Broadcast Engineering
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• v.19 no.2
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• pp.215-226
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• 2014

The 3D technology has been spread slowly and the reason would be attributed to the fact that most commercialized 3D displays require 3D glasses. There have been various researches on human factors of glass type 3D display. In this study we measured and modeled crosstalk as well as 3D visual fatigue induced by mobile glassless 3D display. Crosstalk as well as visual fatigue varied depending on horizontal position of the 3D mobile display. Measured crosstalk was relative low around the center of the display and it increased at the side of the display. Similar results were found in the measurement of 3D visual fatigue and discomfort. These results imply that human factors should be considered in the process of design and evaluation of mobile 3D displays.

• Journal of the Korean Solar Energy Society
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• v.32 no.6
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• pp.100-105
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• 2012

In previous study, to investigate the impression of the compound lighting based on the AC-Model at the full-size room, the impressions of various compound lighting were completed as compared with that of the uniform lightings through the comparison method (a paired comparison) by Semantic Differential scaling. Also, we examined the effect of the supplementary lighting type increasing the lights at the side of the window and the blind-control lighting type, and they were compared with the existing compound lighting type. In results, pared comparison of the compound lighting and the uniform lighting, indicates that the impression of the compound lighting is generally similar to that of the uniform lighting when there are same ratios of the light from the window. Based on these results, we suggest that the AC-Model might be applied to various conditions. And we also introduce the method for daylighting that it is possible to reduce discomfort glare and to improve visual impressions as the supplementary type and blind-control type on the compound lighting. And it was found that electric power consumption of the compound lighting room was lower than that of the uniform lighting room when as same lighting ratio of the compound lighting and the uniform lighting from the window was provided or there was the lighting distribution simulated to same light ratio from the window. Since the method of the ACModel was described in the experimental condition, additional studies should be performed to determine if this model could be applied to different window configurations, lighting layout and types of a room.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.3
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• pp.165-171
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• 2005

The aim of the study was to investigate the diameter and base curve changes of soft contact lens by protein deposition. Soft contact lenses were soaked in artificial tear or protein solution which had the same composition with tear for 2min, 10min, 30min, 1hr, 3hr, 6hr, 12hr, and 24hr. Diameter and base curve changes of soft contact lenses were examined by using the high speed camera(Fastcam ultima 1024). The longer the soaking time of soft contact lenses in the artificial tear, the diameter and base curve changes of soft contact lenses was more increased. In the case of soft contact lenses adsorbed only protein, the similar pattern was shown and the diameter and base curve were decreased. However, the influence of calcium ion was found to be less than that of protein. These results suggest that the tear protein causes the diameter and base curve decrease of soft contact lens, which might be related to the discomfort after soft contact lens wearing.