• Journal of Korean Ophthalmic Optics Society
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• v.17 no.2
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• pp.165-170
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• 2012

Purpose: The aim of this study was to measure and evaluate changes of visual responses in viewing a 2D and 3D (three-dimensional) image. Methods: The subjects were 44 college students aged 19 to 25 years with normal binocular vision. The visual responses measured were CA/C (convergence accommodation/convergence) ratio, convergence-induced PD(interpupillary distance), accommodative responses, perceived distance in viewing a 3D image. Results: Convergence and accommodative responses in viewing the 3D image were significantly larger (p<0.05) than in 2D. A moderate positive correction was found between CA/C ratio and accommodative response (r = 0.477, p = 0.001). It was indicated that smaller PD had larger depth perception. Convergence in viewing the 3D image was significantly larger (p<0.05) than that at cognitive distance. Conclusions: The visual fatigue may be more intense in larger CA/C ratio and smaller PD when viewing 3D images.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.6
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• pp.443-448
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• 2009

For successful visual perception by visual prosthesis using electrical stimulation, it is essential to develop an effective stimulation strategy based on understanding of retinal ganglion cell (RGC) responses to electrical stimulation. We studied RGC responses to repetitive electrical stimulation pulses to develop a stimulation strategy using stimulation pulse frequency modulation. Retinal patches of photoreceptor-degenerated retinas from rd1 mice were attached to a planar multi-electrode array (MEA) and RGC spike trains responding to electrical stimulation pulse trains with various pulse frequencies were observed. RGC responses were strongly dependent on inter-pulse interval when it was varied from 500 to 10 ms. Although the evoked spikes were suppressed with increasing pulse rate, the number of evoked spikes were >60% of the maximal responses when the inter-pulse intervals exceeded 100 ms. Based on this, we investigated the modulation of evoked RGC firing rates while increasing the pulse frequency from 1 to 10 pulses per second (or Hz) to deduce the optimal pulse frequency range for modulation of RGC response strength. RGC response strength monotonically and linearly increased within the stimulation frequency of 1~9 Hz. The results suggest that the evoked neural activities of RGCs in degenerated retina can be reliably controlled by pulse frequency modulation, and may be used as a stimulation strategy for visual neural prosthesis.

• Journal of Digital Convergence
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• v.11 no.10
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• pp.731-736
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• 2013

Recently attention deficit of children has caused various social problems. Those children who has symptoms like ADHD (Attention Deficit/Hyperactivity Disorder) has to be provided with methods which can enhance their attention level in a child-friendly way such as 3D games. This paper shows a research on how to measure the level of attention for attention deficit children using their favorite 3D games. Firstly, we speculated on the methods about attention measurement used in the medical area. And then we searched measurement variables which can effectively evaluate the level of attention during a game play time. Secondly, we have conducted experiment whether there exists difference about the value of the measurement variables between the two groups, normal children group and attention deficit children group. Those variables are omission error, commission error, average response time, and standard deviation of response time. Though our experiment has only been limited to visual attention level, four measurement variables revealed mutual differences.

• Phonetics and Speech Sciences
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• v.8 no.1
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• pp.71-80
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• 2016

The phonemic awareness tasks (phonemic synthesis, phonemic elision, phonemic segmentation) by auditory presentation and visual presentation were conducted to 40 children who are 5 and 6 years old. The scores and error types in the sub-tasks by two presentations were compared to each other. Also, the correlation between the performances of phonemic awareness sub-tasks in two presentation conditions were examined. As a result, 6-year-old group showed significantly higher phonemic awareness scores than 5-year-old group. Both group showed significantly higher scores in visual presentation than auditory presentation. While the performance under the visual presentation was significantly lower especially in the segmentation than the other two tasks, there was no significant difference among sub-tasks under the auditory presentation. 5-year-old group showed significantly more 'no response' errors than 6-year-old group and 6-year-old group showed significantly more 'phoneme substitution' and 'phoneme omission' errors than 5-year-old group. Significantly more 'phoneme omission' errors were observed in the segmentation than the elision task, and significantly more 'phoneme addition' errors were observed in elision than the synthesis task. Lastly, there are positive correlations in auditory and visual synthesis tasks, auditory and visual elision tasks, and auditory and visual segmentation tasks. Summarizing the results, children tend to depend on orthographic knowledge when acquiring the initial phonemic awareness. Therefore, the result of this research would support the position that the orthographic knowledge affects the improvement of phonemic awareness.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.03a
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• pp.237-242
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• 1999

The nature of the interactions between the vestibular and autonomic systems is complex and has not been fully defined. Vestibuloocular reflex induced by sinusoidal rotation and activity of the autonomic nerves in the heart were measured to investigate the interactions between the vestibular system and the autonomic nervous system in healthy adults. Eye movement induced by sinusoidal rotation of the whole body or optokinetic stimulation at 0.04 Hz was analyzed in gain, phase, and symmetry. EKG was measured during vestibular stimulation and analyzed in heart rate variability including mean R-R interval, standard deviation (SD) and coefficient of variance (CV) of R-R interval, and power spectrum of low frequency region (LF) and high frequency region (HF). Gain of eye movement was 0.65${\pm}$0.03 by ratatory stimulation, 0.70${\pm}$0.02 in optokinetic stimulation, 0.08${\pm}$0.02 in visual suppression, and 0.84${\pm}$0.04 in visual enhancement. In R-R interval, resting condition (control) was 0.82${\pm}$0.03 sec, and visual suppression showed significant increase and visual enhancement did significant decrease compared with control (p<0.01).CV was 0.06${\pm}$0.02 in control and visual enhancement increased significantly (p<0.05). In LF/HF control was 1.40${\pm}$0.23, which was not different from rotatory or optokinetic stimulation. But visual suppression decreased LF/HF significantly and visual enhancement increased significantly compared with control (p<0.01). These results suggest that degree of gain corresponds with LF/HF and increased gain in visual enhancement is deeply related to the activity of sympathetic nerves.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.4
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• pp.303-309
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• 2010

We proposes a new approach for testing the self visual-acuity by using the KS standard optotype. The proposed system provides their hand-gesture recognition method for the convenient response of subjects in the visual acuity measurement. Also, this system can measure a visual-acuity that excludes the examiner's subjective judgement or the subject's memorized guess, because of presenting a random optotype automatically by computer without a examiner. Especially, Our system guarantees the reliability by using the KS standard optotype and its presentation(KS P ISO 8596), which is defined by the Korea Standards Association in 2006. And the database management function of our system can provide the visual-acuity data to the EMR client easily. As a result, Our system shows the 98% consistency in the limit of the ${\pm}1$ visual-acuity level error by comparing the visual-acuity chart test.

• Journal of Korea Multimedia Society
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• v.21 no.8
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• pp.960-968
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• 2018

The mobile visual search service uses a query image to acquire linkage information through pre-constructed DB search. From the standpoint of this purpose, it would be more useful if you could perform a search on a web-based keyword search system instead of a pre-built DB search. In this paper, we propose a representative query extraction algorithm to be used as a keyword on a web-based search system. To do this, we use image classification labels generated by the CNN (Convolutional Neural Network) algorithm based on Deep Learning, which has a remarkable performance in image recognition. In the query extraction algorithm, dictionary meaningful words are extracted using Wikipedia, and hierarchical categories are constructed using WordNet. The performance of the proposed algorithm is evaluated by measuring the system response time.

• Journal of the Korea Society of Computer and Information
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• v.9 no.2
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• pp.57-62
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• 2004

In these days, application systems for processing information using database is increasing. Enterprises holding a lot of data do not possess needed data but instead include unrelated, independent and individual data. As a result, it only contains disparate data. Disparate data is ambiguous and it does not support current integrated information. In response to the above problems, data warehouse may provide a solution. Building a data warehouse needs a systematic design because of its complexity. This paper describes an efficient design methodology using visual environment for data warehouse to cope with the requirements of end users. Also, the system is able to process existential SQL query.

• Proceedings of the IEEK Conference
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• summer
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• pp.128-132
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• 2004

In this paper, we propose a new image quality assessment scheme considering the human visual perception characteristics. A subjective quality assessment is obtained by the response of the receptive field in the primary visual cortex and a human's eye can't focus on all of the visual range in a moment. Take advantage of two facts above, we apply Gabor wavelet transform, which is well fit the receptive field in the cortex, to divided constant sized subblocks. Then a local distortion of the subblocks and a global distortion for the entire image are calculated in order. The proposed method has been evaluated using video test sequences provided by the Video Quality Experts Group (VQEG). The experimental results show that good correlation with human perception is obtained using the proposed metric, which is what we called GPSNR.

• Proceedings of the Korea Contents Association Conference
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• 2018.05a
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• pp.45-46
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• 2018

본 논문에서는 VR 시뮬레이션 플랫폼의 프레임 웍에 기반하여 게임 엔진을 활용한 통합훈련 VR 시뮬레이션 플랫폼을 제작하고 그 사례를 소개한다. 본 VR 시뮬레이션 플랫폼을 활용하면 전문 직종 종사자들이 아닌 일반인들이 실생활에서 겪을 수 있는 재난 상황에 대해 행동요령을 훈련할 수 있다. 이 VR 시뮬레이션 플랫폼은 재난 상황에 대해 반복적이고 안전하게 행동요령을 익힐 수 있으며, 본 제작 과정은 VR 시뮬레이션 플랫폼 개발의 제작단계에서 유용하게 참고 될 자료라 사료된다.