• Journal of the Korea Society of Computer and Information
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• v.26 no.6
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• pp.129-135
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• 2021

The purpose of this study was to investigate the relationship of the head posture with the tone and stiffness of the cervical extensor muscles. Eighty adults in their twenties were chosen as subjects, and the tone and stiffness of the cervical extensor muscles were measured, with their usual head posture in the sagittal plane. For the measured head posture, the craniovertebral angle (CVA), craniorotation angle (CRA), and forward shoulder angle (FSA) were analyzed using Image J. It was observed that the tone and stiffness of the upper trapezius muscle increased significantly with a decrease in the CVA as well as with an increase in the CRA (p < 0.05). As a result of further classification into the normal and forward head postures based on the CVA of the subjects, the forward head posture was characterized by a significant increase in the tone and stiffness of the upper trapezius muscle (p<.05). The results of this study are expected to be used as basic data for the evaluation of the forward head posture and posture education in clinical practice.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.839-842
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• 2005

본 논문은 스테레오 카메라를 통해 얻은 변이 정보를 이용하여, 3 차원으로 머리의 회전 각도를 추정하는 방법을 제안한다. 머리 회전에 의한 주시 방향은 사람이 관심을 가지는 방향이므로 이동을 추정하는 것에 비해 많은 중요성을 갖는다. 본 논문에서는 얼굴 영역 내의 여러 특징점들 중 3 개의 특징점들을 포함하는 여러 평면(Plane)이 머리가 이동하더라도, 그 평면들 사이의 각은 변하지 않으므로, 회전 각도 추정에 영향을 주지 않는 점을 이용하여 회전 각도를 추정하였다. 또한, 기존 논문이 카메라 보정을 통해 3 차원 위치를 측정하지만, 제안하는 방법은 변이 공간에서 회전 각도를 추정하기 때문에 카메라 보정 과정이 필요하지 않다. 변이 정보를 얻기 위한 스테레오 장비는 평행 카메라 모델로 가정하며, 얼굴 내의 특징점은 KLT(Kanade-Lucas-Tomasi) 특징 추적 알고리즘을 이용하였다. 실험결과는 기준 영상에 대하여 추정된 3 차원 각도를 나타낸다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.201-204
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• 2008

머리전달함수(HRTF)가 정확하더라도 사람의 얼굴이 움직이게 되면 실제 머리전달함수와 미리 측정한 머리전달 함수가 달라져 입체음향 시스템의 성능이 저하되므로 정확한 얼굴의 회전각이 요구된다. 따라서 본 논문에서는 정확한 머리전달함수의 입력을 위해 사람 얼굴의 회전각을 추정하고자 한다. 제안하는 알고리즘은 먼저 Haar-like 특징을 이용하여 얼굴을 검출한 후 전처리 작업을 통해 눈의 바깥쪽 경계면과 안쪽 경계면을 검출한다. 그리고 검출된 두 개의 경계면의 비를 이용하여 얼굴의 회전각을 추정한다. 제안하는 알고리즘은 기존에 방법들에 비해 적용 범위가 넓음을 실험을 통해 알 수 있었다.

• The Journal of the Korea Contents Association
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• v.11 no.10
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• pp.293-300
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• 2011

This study was to find out the effect of cervical and thoracic stretching and strengthening exercise program on forward head posture. 32 adults had forward head posture were selected as the subjects for the study. The training program of the exercise group(n=16) consist of postural education with exercise program, subjects in the control group(n=16) participated in a postural education only. Postural measurements of Craniovertebral Angle(CVA) and Cranial Rotation Angle(CRA) were obtained from the using x-ray and PACS(Picture Archiving and Communications System) ${\pi}view^{TM}$. The results were compared with change of CVA and CRA exercise group were significant(p<.05) compared to the control group. However CRA of contol group was significant(P<.05). Also, there were no significant difference(p>.05) between groups on any pre-test measure. however there were significant difference(p<.05) between groups on CVA and CRA post-test measure. This study showed that cervical and thoracic stretching and strengthening exercise program can improve spinal posture alignment for decreasing forward head posture in subjects. These results can be fundamental data for further development of exercise program in interventions of postural improvement.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.166.1-166.1
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• 2012

최근에는 정지궤도위성에도 지구센서 대신 별추적기를 탑재하는 추세이다. 별추적기의 경우 태양이나 지구와 같은 밝은 물체가 시야각에 들어올 경우 자세결정을 수행할 수 없기 때문에 별추적기 최적 배치를 위한 해석이 요구된다. 그런데, 정지궤도위성의 경우 24시간을 주기로 태양이 적도면을 회전하고 또한 동지와 하지를 최대로 하여 적도면과 23.5도의 기울기를 갖고 있기 때문에 별추적기 배치에 많은 제한이 발생한다. 별추적기 성능을 최적으로 얻기 위해서는 탑재되는 광학계가 서로 직각이 되어야 하지만 태양 위치에 따른 제한으로 인해 직각이 될 수 없으며 이 경우 성능은 약간의 손실을 감수하면서 항상 태양을 회피하기 위한 최적 각을 적용하거나 태양이 들어올 경우만 성능 손실을 감수하면서 이외의 경우에 별추적기 최적의 성능을 얻고자 하는 방법이 있을 수 있다. 본 연구에서는 이러한 방법들에 대한 해석을 수행하여 최적 각을 소개하였고, 다중머리 별추적기를 대상으로 해석을 수행하였다. 다중머리 별추적기는 하나의 전장품에 광학계가 여러 개 장착되는 제품으로 최근에 우주이력(heritage)를 갖기 시작하였다.

• The KIPS Transactions:PartB
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• v.10B no.4
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• pp.465-472
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• 2003

For an effective pre-treatment process of a face input image, it is necessary to detect each of face components, calculate the face area, and estimate the rotary angle of the face. A proposed method of this study can estimate an robust result under such renditions as some different levels of illumination, variable fate sizes, fate rotation angels, and background color similar to skin color of the face. The first step of the proposed method detects the estimated face area that can be calculated by both adapted skin color Information of the band-wide HSV color coordinate converted from RGB coordinate, and skin color Information using histogram. Using the results of the former processes, we can detect a lip area within an estimated face area. After estimating a rotary angle slope of the lip area along the X axis, the method determines the face shape based on face information. After detecting eyes in face area by matching a partial template which is made with both eyes, we can estimate Y axis rotary angle by calculating the eye´s locations in three dimensional space in the reference of the face area. As a result of the experiment on various face images, the effectuality of proposed algorithm was verified.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.293-296
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• 2000

본 논문에서는 최근 신원확인 수단으로 각광받고 있는 생체인식 중 가장 신뢰도가 높은 홍채인식에 관한 연구에 대해 기술하고 있다. 비접촉식 홍채인식 시스템의 경우 홍채영상의 획득 시 사람의 머리가 기울어지거나 움직임에 따라 영상이 좌측 혹은 우측으로 조금씩 회전, 혹은 이동하거나 크기가 달라지게 된다. 이런 경우 동일인의 홍채영상도 매번 조금씩 달라지게 되므로, 정확한 인식을 위해서는 획득된 각 영상의 정규화 과정과 함께 회전된 영상에 대한 보완 등의 전처리 과정이 매우 중요하다. 영상 필터를 통한 정확한 외곽 경계의 검출과 정규화, 비교방법을 통해 이를 보완하고, 웨이블렛 변환을 이용하여 특징값을 얻은 후 검증 실험 결과를 보임으로써 회전, 이동, 크기에 무관한 홍채 인식 방법을 제안하고자 한다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.5
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• pp.57-64
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• 2004

We proposed the eye gaze tracking system under natural head movements, which consists of one narrow-view field CCD camera, two mirrors which of reflective angles are controlled and active infra-red illumination. The mirrors' angles were computed by geometric and linear algebra calculations to put the pupil images on the optical axis of the camera. Our system allowed the subjects head to move 90cm horizontally and 60cm vertically, and the spatial resolutions were about 6$^{\circ}$ and 7$^{\circ}$, respectively. The frame rate for estimating gaze points was 10～15 frames/sec. As gaze mapping function, we used the hierarchical generalized regression neural networks (H-GRNN) based on the two-pass GRNN. The gaze accuracy showed 94% by H-GRNN improved 9% more than 85% of GRNN even though the head or face was a little rotated. Our system does not have a high spatial gaze resolution, but it allows natural head movements, robust and accurate gaze tracking. In addition there is no need to re-calibrate the system when subjects are changed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.624-631
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• 2017

This study aimed to identify the effect of the push-up plus exercise with sling on the muscle activity and lung function in adults with forward head posture over a period of 8 weeks. A total of 16 adults with forward head posture were recruited. The participants were divided into two groups : control (n-=8) and experimental (n=8). From July 6 until Aug 28, 2015, the participants were instructed to perform the knee push-up plus exercise and knee push-up plus using sling exercise three times a week to begin with and progressing to three sets of push-ups on each occasion after 8 weeks. The participants in both groups showed an increase in their craniovertebral angle (both groups p<0.001) and a decrease in their crania rotation angle (control p<0.05, experimental p<0.001). The participants in both groups showed a decrease in their trapezius activity (both groups p<0.001), an increase in their serratus anterior and lower trapezius muscle activity (both groups p<0.001), (and an increase in their) lung function (control group p<0.01, experimental group p<0.001). These findings show that push-up plus exercise improves posture and increases activation of lung function, while the push-up plus exercise in the sling is more effective in improving the forward head posture. The push-up plus exercise in the sling was more effective in improving the forward head posture, but there was no significant difference in the lung function between the two groups. Therefore, the push-up plus exercise in the sling is recommended as an exercise that is effective for the improvement of the posture and lung function of persons with forward head posture.

• Journal of Korean Physical Therapy Science
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• v.19 no.2
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• pp.17-24
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• 2012

Purpose : The purpose of this study was to show the effect of postural training through action observation (AO) on craniovertebral angle (CVA) and cranial rotation angle (CRA) of forward head posture (FHP). Methods : From 16 subjects of having the FHP who consist of postural training through the AO (n = 8) and control group (n = 8) were training to three times per one week during three weeks. FHP measurements for pre and post the intervention use to Wiz-pacs(Wiz-Picture Achiving Communication System) from X-ray change of CVA and CRA. Results : The study for the change within the group pre and post the intervention, CVA and CRA were found the significant differences only in the postural training group through the AO (p<.05). In the comparison of the rates of change between the groups pre and post the intervention CVA and CRA all showed the significant differences (p<.05), and in the comparison of the rates of average change of individual variables in each groups, the postural training group through the AO showed more change rates. Conclusion : The study suggests that when people with FHP received the postural training, the postural training through the AO resulted in more change into the correct postures.