• Communications of Mathematical Education
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• v.27 no.1
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• pp.1-17
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• 2013

This work started with recent students' conception on Linear Algebra. We were trying to help their understanding of Linear Algebra concepts by adding visualization tools. To accomplish this, we have developed most of needed tools for teaching of Linear Algebra class. Visualizing concepts of Linear Algebra is not only an aid for understanding but also arouses students' interest on the subject for a better comprehension, which further helps the students to play with them for self-discovery. Therefore, visualizing data should be prepared thoroughly rather than just merely understanding on static pictures as a special circumstance when we would study visual object. By doing this, we carefully selected GeoGebra which is suitable for dynamic visualizing and Sage for algebraic computations. We discovered that this combination is proper for visualizing to be embodied and gave a variety of visualizing data for undergraduate mathematics classes. We utilized GeoGebra and Sage for dynamic visualizing and tools used for algebraic calculation as creating a new kind of visual object for university math classes. We visualized important concepts of Linear Algebra as much as we can according to the order of the textbook. We offered static visual data for understanding and studied visual object and further prepared a circumstance that could create new knowledge. We found that our experience on visualizations in Linear Algebra using Sage and GeoGebra to our class can be effectively adopted to other university math classes. It is expected that this contribution has a positive effect for school math education as well as the other lectures in university.

• Journal of Korea Multimedia Society
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• v.7 no.11
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• pp.1550-1555
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• 2004

Shadows increase the visual realism of computer-generated images and they are good hint for spatial relationships between objects. Previous methods to produce a shadow texture for an object are to render all objects between the object and light source. Consequently entire time for generating shadow textures between all objects is Ο(Ν$^2$), where Ν is the number of objects. We propose a novel shadow texture generation method with constant processing time for each object using shadow depth buffet. In addition, we also present method to achieve further speed-up using temporal coherence. If the transition between dynamic and static state is not frequent, depth values of static objects does not vary significantly. So we can reuse the depth value for static objects and render only dynamic objects.

• Physical Therapy Korea
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• v.22 no.3
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• pp.1-11
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• 2015

The purpose of this study was to investigate the effect of lumbar stabilization training and additional thoracic mobilization on pain, proprioception and static balance in patients with chronic low back pain. The subjects of this study were 48 chronic low back pain patients who were randomly allocated to an experimental group 1 ($n_1=16$, lumbar stabilization and thoracic mobilization, thoracic hypomobility), experimental group 2 ($n_2=16$, lumbar stabilization and thoracic mobilization, thoracic normal mobility), and a control group ($n_3=16$, lumbar stabilization, thoracic hypomobility) after a thoracic mobility test. Both experimental groups underwent lumbar stabilization training and additional thoracic mobilization. The control group underwent only lumbar stabilization training. The intervention was performed 3 times per week, 30 minutes each time, for a total of 6 weeks. Thoraco-lumbar joint reposition error was measured using an electrogoniometer and static balance ability was measured using the Tetrax posture analysis system. Subjects' pain level was measured using a 100 mm visual analogue scale. Statistical analyses were performed using a one-way analysis of variance and a paired t-test. Post-hoc testing was carried out with a Bonferroni test. The pain level was significantly lower in both experimental groups compared to the control group. Both experimental groups showed significant reductions in joint reposition error angle (flexion, extension, and side bending) compared to the control group. The static balance level was significantly lower in both experimental groups than in the control group. In summary, lumbar stabilization exercises and additional thoracic mobilization significantly improved the pain level, proprioception, and static balance in patients with chronic low back pain.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.9 no.2
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• pp.13-23
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• 2011

Purpose : The purpose of this study is to investigate the effect on the static balance ability according to vestibular training using ball. Methods : Twenty normal subjects participated and were randomly assigned to either a vestibular training group using ball or a control group. The vestibular training using a ball group exercised 3 times per week over 3 weeks. The static balance was assessed by the center of pressure to the stance position. The participants stood barefoot on a force platform in a normal stance and a one-legged stance with a visual close. Results : In the normal stance, there were no significant differences at CoP surface and CoP speed. However, in a one-legged stance, there were significant differences in the vestibular training group between before and after the program. There was also a significant difference between the vestibular training group and the control group. Conclusion : Vestibular training using ball can be implemented as a therapeutic intervention to improve static balance ability in health adults.

• PNF and Movement
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• v.18 no.2
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• pp.265-273
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• 2020

Purpose: The purpose of the study was to investigate the effects of HMD (head mounted display)-based virtual reality balance training on static balance in young adults, and whether appropriate balance training can help healthy adults to improve balance ability in daily living. Methods: The study subjects were 14 healthy adults. Subjects received 20 minutes of HMD-based virtual reality balance training 3 times per week for 4 weeks. Static balance was measured before, during, and after training and after one month. Static balance was measured in a total of 8 conditions, and the results were classified as visual (F1), somatosensory (F5-6), vestibular (F2-4), and central nervous system (F7-8). Results: The test results showed no significant difference in pre-training, post-training, and follow-up results under all conditions at Fourier index F1, F5-6, and F7-8 frequencies. For the F2-4 frequency, there was a significant difference before and after training under NC (neutral head position, eyes closed, firm surface) and PC (neutral head position, eyes closed, elastic surface) conditions. The NC condition returned a significant decrease of F2-4 frequency in post-training testing as compared to pre-training, and the PC condition showed a significant decrease of F2-4 frequency between the pre-training and mid-training tests, and between the pre-training and post-training tests. Conclusion: These results indicate that HMD-based balance training can improve balance ability, even in normal adults, and seems especially effective for vestibular function training.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.681-684
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• 2008

Motion interpolation is adopted and has been spread widely into market since it is effective in reducing motion blur, which is considered as weak characteristic due to slow response time of liquid crystal and hold-type display. 120Hz driving using interpolated frames achieves better moving picture quality with less motion blur and less motion judder. However, errors in the interpolated frames can cause visual artifacts such as static text breakup, halos, and occlusions. This paper focuses on categorizing characteristics of visual artifacts and on reducing side-effects by using information from original frames in special cases.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.868-870
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• 2005

스크래치는 오래된 필름에서 가장 많이 나타나는 손상 요인이다. 고화질의 멀티미디어 서비스를 제공하기 위해서는 이러한 스크래치들은 반드시 검출 및 복원되어야 한다. 이러한 중요성 때문에 지금까지 많은 복원 알고리즘이 개발되어 왔으나, 스크래치 영역의 자동검출에 대한 연구는 거의 이루어지지 않은 실정이다. 따라서 본 논문에서는 자동으로 스크래치영역을 추출할 수 있는 신경망 기반의 검출 방법을 제안한다. 다층 퍼셉트론 (Multi-layer perceptron: MLP)을 이용하여 스크래치영역과 비 스크래치영역을 구분하는데, 이 MLP는 다양한 크기의 스크래치를 검출하기 위해 다양한 크기의 입력 영상에 대해 적용된다. 제안된 방법의 평가를 위해 principal/ secondary 스크래치, alone/not-alone 스크래치, moving/static 스크래치등의 다양한 종류의 스크래치를 가진 영상에 대해 실험이 이루어졌고, 그 결과 제안된 방법의 강건함과 효율성을 입증되었다.

• Journal of Korean Physical Therapy Science
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• v.11 no.2
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• pp.38-45
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• 2004

Appropriate physical position and balance means giving the least stress and the most useful biomechanically to the body. As this fails, one would have functional recovery problem regardless of disability. There reported better effective on Dynamic training rather than Static training for a proper recovery of physical position, and additionally required Sensory Feedback. Those who have disability of balance, especially Central Nervous System lesion should he provided with variety of Sensory Feedback, and also Dynamic Balance training used by is quite effective.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.4
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• pp.85-95
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• 1998

In this paper, a new watermarking method for a copy protectionof images is proposed. The proposed method adaptively embeds a watermark in the frequency domain of images using human visual system model. For this purpose, the Just Noticeable Differences(JNDs) of each frequency coeffeicient value of a luminance plane is first found using Watson and Solomon's visual system model. An invisible maximum watermark value with is different in every position according to the characteristics of images is determined usig JND and Minkowski metric. A low frequency domain is divided into two sets based on a PN-sequence to protect thewatermark from the attack. The watermarks are added to one set of coefficients and detecting a watermark, the difference between the mean values of absolute coefficient values of both sets is calculated. The embedded watermark is tested using statistical hypothesis based on test static dertermined by the ean difference. To demonstrate the perfromance of the proposed method, the new watermarking method is applied to a high frequency image and low frequency images. Experimenatal results show the watermark is invisible and robust to JPEGlossy compression and noise.

• Journal of information and communication convergence engineering
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• v.3 no.1
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• pp.56-61
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• 2005

In this paper, we present a video rate control scheme for storage and delivery in which the time-varying viewing interests are controlled by human gaze. To track the gaze, the pupil's movement is detected using the three-step process : detecting face region, eye region, and pupil point. To control bit rates, the quantization parameter (QP) is changed by considering the static parameters, the video object priority derived from the pupil tracking, the target PSNR, and the weighted distortion value of the coder. As results, we achieved human interfaced visual model and corresponding region-of-interest rate control system.