• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.4
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• pp.639-645
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• 2007

Removable or fixed space maintainer could be needed if one or some anterior primary teeth were missing, where resin pontics well-matched to natural primary teeth should be demanded to get an esthetic satisfaction. Resin Natural $Teeth^{TM}$(Nissin dental, Japan) is available currently in Korea, which consists of two shades of colors; type A1 and A2. The purpose of this study is to elucidate the colors of the anterior primary resin teeth and to establish the data to compare those with the natural anterior primary teeth. CIE $L^*a^*b^*s$ were measured each three times labially from 17 sets of maxillary four anterior teeth for type A1 and A2 Resin Natural $Teeth^{TM}$ using ShadeEye $NCC^{TM}$(Shofu, Japan) which is one of spectrophotometers. The data were analysed statistically using Kruskall-Wallis Test and Mann-Whitney U Test. The results were as follows : 1. There were smaller teeth color differences in group A1 than in group A2 when it comes to distributions of ${\Delta}E$, $L^*$ and $b^*$. There were no statistically significant differences of $a^*$ between teeth in the same group(P>0.05). 2. ${\Delta}E$ in group A1 and A2 (maximum ${\Delta}E{\le}1.23$) were very small, which could not be discerned by eyesight. ${\Delta}E$ between mean CIE $L^*a^*b^*s$ of group A1 and A2 was 3.97, which could be discernible by eyesight. 3. Mean measurements of group A1 were $L^*=73.8$, $a^*=-1.8$, $b^*=-4.7$, and those of group A2 were $L^*=75.8$, $a^*=-2.7$, $b^*=-1.4$. It would be recommended that resin teeth compatible to the colors of the natural primary ones needed to be developed by investigating in vivo study.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.5
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• pp.171-180
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• 2023

The three major sleep disorders in Korea are snoring, sleep apnea, and insomnia. Lack of sleep is the root of all diseases. Some of the most serious potential problems associated with sleep deprivation are cardiovascular problems, cognitive impairment, obesity, diabetes, colitis, prostate cancer, etc. To solve these problems, the Korean government provided low-cost national health insurance benefits for polysomnography tests in July 2018. However, insomnia patients still have problems getting treated in terms of time, space, and economic perspectives. Therefore, it would be better for insomnia patients to be allowed to test at home. The measuring device can measure six biosignals (eye movement, tossing and turning, body temperature, oxygen saturation, heart rate, and audio). A gyroscope sensor (MPU9250, InvenSense, USA) was used for eye movement, tossing, and turning. The input range of the sensor was in 258°/sec to 460°/sec, and the data range was in the input range. Body temperature, oxygen saturation range, and heart rate were measured by a sensor (MAX30102, Analog Devices, USA). The body temperature was measured in 30 ℃ to 45 ℃, and the oxygen saturation range was 0% for the unused state and 20 % to 90 % for the used state. The heart rate measurement range was in 40 bpm to 180 bpm. The measurement of audio signal was performed by an audio sensor (AMM2742-T-R, PUIaudio, USA). The was -42 dB ±1 dB frequency range was 20 Hz to 20 kHz. The measured data was successfully received in wireless network conditions. The system configuration was consisted of a PC and a mobile app for bio-signal measurement and data collection. The measured data was collected by mobile phones and desktops. The data collected can be used as preliminary data to determine the stage of sleep and perform the screening function for sleep induction and sleep disturbances. In the future, this convenient sleep measurement device could be beneficial for treating insomnia.

• Journal of the Korea Computer Graphics Society
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• v.17 no.4
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• pp.31-40
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• 2011

Projector-based visual systems are widely used for VR and experience display applications. But the illumination irregularity on the screen surface due to the screen material and its light reflection properties sometimes deteriorates the user experience. This phenomenon is particularly troublesome when the participants of the head tracking VR system such as CAVE or the motion generation experience system continually move around the system. One of reason to illumination irregularity is projector-screen specular reflection component to participant's eye's position and it's analysis needs high computation complexity. Similar to calculate specular lighting term using GPU's programmable shader, Our research adjusts every pixel's brightness in runtime with given 3D screen space model to reduce illumination irregularity. For doing that, Angle-based brightness compensate function are considered for specific screen installation and modified it for GPU-friendly compute and access. Two aspects are implemented, One is function access transformation from angular form to product and the other is piecewise linear interpolate approximation.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.45-61
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• 2005

Stance is defined as any state in which the total mass of the body is supported by the feet. In order to maintain stance, the sum of gravito-inertial forces acting on the body must be registered by equal and opposite forces at the region of contact between the organism and the support surface. Balance is controlled by applying forces to the surface of support so as to maintain the body's center of mass vertically above the feet. for a muIti-segment organism, there can be a variety of ways in which balance can be controlled, since movements of different body segments can have similar effects on the control of balance. In general, the organism tends to have a body configuration that is aligned with gravito-inertial force when there are no external forces acting on it. If any segments of the body are not aligned with gravito-inertial force vector, a torque on that segment would tend to move the body's center of mass. The maintenance of postural stability is accomplished in humans by a complex neural control system. This requires organizing integrating and acting upon visual, vestibular, and somatosensory input, providing orientation information to the postural control system. The information necessary to control and coordinate movement is provided by the visual sense of eye position with respect to the surrounding surface layout, the vestibular sense of head orientation in the gravito-inertial space, and the somatic sense of body segment position relative to one another and to the support surface. In this study, perception and action capability was examined from various points of view. The underlying assumption of the study was that the change of postural configuration could be effected by organism, environment and task goal.

• Korean Journal of Health Education and Promotion
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• v.25 no.3
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• pp.95-109
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• 2008

Objectives: The study was conducted to investigate visual display terminal(VDT) and related risk factors in office workers. Method: The study subjects were 539 officers at 3 places of business in Gwangju. The data were collected by self-administered questionnaire between October 12 and October 17, 2007. and they agreed to participate in this study. The tool was developed by Moon, Jaedong(1991) for VDT syndrome. Data analysis by using SPSS/win 10.0 was performed with descriptive statistics, t-test and ANOVA. Results: The summary of results is as follows: 1) The mean score of total VDT syndrome was $1.17{\pm}.65$ of full score 4.00, which was lower than other research. 2) For relation between general characteristics and total VDT, sex (t=-5.777, p=.000), age (F=3.516, p=.015), satisfaction of job (F=9.540, p=.000), self-awareness of health (F=25.015, p=.000) had statistically significant difference. 3) For relation between behavioral work factors and total VDT, break time of work(t=-5.363, p=.000), eye movement during computer work(t=2.176, p=.031), wrist exercise during(t=2.337, p=.020), distance between monitor and eyes(F=3.682, p=.012) had statistically significant difference. 3) For relation between environmental work factors and total VDT, height of chair(F=8.801, p=.000), space under desk(F=4.244, p=.015), reflection of monitor(t=2.697, p=.008) had statistically significant difference. Conclusion: To prevent and relieve VDT syndrome and musculoskeletal disorders in office workers, it is important to teach good posture and stretching exercise during work.

• Archives of design research
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• no.18
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• pp.153-162
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• 1996

underground space have many negative environmental clements which should be confirmed on location and line of action by the artificial signs. iccordingly, environmental graphics as visual language for popular signification-function have to be studied on sign theory of symbolic meanings. Ho\/ever, its usage has not only decorated by microscopiC appreciative eye but also lost its meanlllg as a visual language which was caused by the negligence of systematic management of the facility in charge Result of study, Visual environmental factors as a cause of behavioral attitude based on the study, which has been carefully considered as a communication of the visual language. Therefore, considering the underground environmental graphics as the: sign or the signification-function, It has to be studied on syntactic, semantic and pragmatic viewpoint. SpeCifically, to maKe the color and formation language a signification-function as a generalized connotation to the public, a distinctive classified Visual language must be applied.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.4
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• pp.1-7
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• 2009

This study investigated the actual conditions of the illumination environment from agricultural youth study room. The result, average space of the study room was 11.42[$m^2$]. The illuminant uses the fluorescent lamp mainly, Method of using illumination was only general illumination the case which uses 73.8[%]. Method of light distribution was a direct lighting mainly. The house which has a stand illumination was also 45.7[%], The percentage using the stand illumination which was a local illumination was nothing but in 20[%] of the whole subject of investigation, therefore eye work could not effective. The internal illuminance was average 131.82[lx], the desk illuminance was 253.64[lx] which was the minimum permitted limit and poor. Uniformity ratio of illuminance appeared with average 35.61[%]. The satisfaction with 3.93 points to be high for illumination environment, therefore it was thought that the recognition of illumination was very insufficient.

• The Journal of Advanced Prosthodontics
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• v.5 no.3
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• pp.312-318
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• 2013

PURPOSE. The aim of this study was to compare the passivity of implant superstructures by assessing the strain development around the internal tapered connection implants with strain gauges. MATERIALS AND METHODS. A polyurethane resin block in which two implants were embedded served as a measurement model. Two groups of implant restorations utilized cement-retained design and internal surface of the first group was adjusted until premature contact between the restoration and the abutment completely disappeared. In the second group, only nodules detectable to the naked eye were removed. The third group employed screw-retained design and specimens were generated by computer-aided design/computer-aided manufacturing system (n=10). Four strain gauges were fixed on the measurement model mesially and distally to the implants. The strains developed in each strain gauge were recorded during fixation of specimens. To compare the difference among groups, repeated measures 2-factor analysis was performed at a level of significance of ${\alpha}$=.05. RESULTS. The absolute strain values were measured to analyze the magnitude of strain. The mean absolute strain value ranged from 29.53 to 412.94 ${\mu}m/m$ at the different strain gauge locations. According to the result of overall comparison, the cement-retained prosthesis groups exhibited significant difference. No significant difference was detected between milled screw-retained prostheses group and cement-retained prosthesis groups. CONCLUSION. Within the limitations of the study, it was concluded that the cement-retained designs do not always exhibit lower levels of stress than screw-retained designs. The internal adjustment of a cement-retained implant restoration is essential to achieve passive fit.

• Journal of Korean Academy of Nursing
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• v.30 no.1
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• pp.225-239
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• 2000

This study is a research of conceptual development to find the factors of presence. The concept and the definition of presence received from literary review. On the basis of these findings, we formulate the contents of presence through structured interview guide composed of open-ended questionnaire which included the frequency, attitude, and posture. We selected 104 samples who are the patients, doctors, nurses, and other health providers. And then the contents of presence were established after integrating the formulated contents and putting them in order. The categorizing of the presence was made after discussing with specialist in this field. By using the selected contents, we made 25 statements of presence which were categorized into three factors. The results were as follows: 1. The definition of presence is being with at the same time and space, making attention with openness, and the therapeutic interaction with empathy. 2. The contents of presence through personal interviews are The time required is 5 minutes(46.15%), 2-3 minutes(34.61%), and 10 minutes (15.38%) respectively. The frequency of visiting is 3 times(39.20%), every time(23.07%), and more than 5 times(20.19%) respectively. \circled2 In case of being with nurse is having pain(39.42%), suffering trouble or severe fear(9.61%), feeling discomfort(8.65%), taking care of wound(7.69%), and other unfavorable symptoms(6.73%) respectively. \circled3 The posture being with nurse is depends on the situations(63.46%), sitting(26.92%), and standing(9.61%) respectively. Eye contact with nurse is face to face(78.84%), depends on the situations(20.19%), and not face to face(0.96%) respectively. \circled4 The attitudes of comfort are explaining about disease(23.07%), holding on hands (14.42%), touching on the suffering parts (11.53%), and unconditionally being with(7.69%) respectively. \circled5 Nurses' caring actions are kindness (27.88%), replying to the question (12.50%), smiling(10.57%), bright appearances (8.65%), and right and quick treatment(8.65%) respectively. \circled6 The effects of being with are peaceful mind(58.65%), quick recovery(13.46%), and decrease in fear(12.50%) respectively. \circled7 The attitudes of being with are listening (11.53%), recognition(8.65%), talking about discomfort(8.65%), and answering kindly (7.69%) respectively. 3. From the analysis of presence factors, 25 statements and 3 categorized factors are presented.

• Electronics and Telecommunications Trends
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• v.35 no.4
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• pp.65-80
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• 2020

In this article, we review the study trends of three-dimensional (3D) displays that can display stereoscopic images from the perspective of a display device. 3D display technology can be divided into light field, holographic, and volume displays. Light field display is a display that can reproduce the intensity and direction of light or 'ray' in each pixel. It can display stereoscopic images with less information than a holographic display and does not require coherence of the light source. Therefore, it is expected that it will be commercialized before the holographic display. Meanwhile, the holographic display creates a stereoscopic image by completely reproducing the wavefront of an image using diffraction in terms of wave characteristics of light. This technology is considered to be able to obtain the most complete stereoscopic image, and the digital holographic display using a spatial light modulator (SLM) is expected to be the ultimate stereoscopic display. However, the digital holographic display still experiences the problem of a narrow viewing angle due to the finite pixel pitch of the SLM. Therefore, various attempts have been made at solving this problem. Volumetric display is a technology that directly creates a stereoscopic image by forming a spatial pixel, which is known as a volumetric pixel, in a physical space, and has a significant advantage in that it can easily solve the problem of the viewing angle. This technology has already been tested for commercial purposes by several leading companies. In this paper, we will examine recent research trends regarding these 3D displays and near-eye display that is emerging as a significant application field of these technologies.