• Title, Summary, Keyword: Convergent fixation

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The Relationship between Fixation and Brain Preference (고착(Fixation)과 뇌활용성향과의 관계)

  • Lee, Hong;Jun, Yun-sook;Park, Eun-a
    • Knowledge Management Research
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    • v.6 no.1
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    • pp.85-103
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    • 2005
  • The purpose of this study was to identify the relationship between fixation and brain preference. Based on the hemisphere asymmetric theory and fixation, two hypotheses were articulated. They were: 1) Right-brain preference is negatively related to divergent fixation. 2) Left-brain preference is negatively related to convergent fixation. A self-reporting scale for measuring the brain preference with 42 items were developed for the study based on functional characteritics of left and right hemisphere. Samples were collected from 579 college students in K University. Regression analysis showed that right-brain preference was negatively associated with divergent fixation. In the relationship between left-brain preference and convergent fixation, mixed results were produced. Research implication were discussed at the end of the study.

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Depth Extraction of Convergent-Looking Stereo Images Based on the Human Visual System (인간시각체계에 기초한 교차시각 스테레오 영상의 깊이 추출)

  • 이적식
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.4A
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    • pp.371-382
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    • 2002
  • A camera model with optical axes parallel has been widely used for stereo vision applications. A pair of input ages are obtained from a convergent-looking stereo camera model based on the human visual system in this per, and each image is divided into quadrant regions with respect to the fixation point. The reasoning of quadrant partitions is based on the human visual system and is proven by a geometrical method. Image patches : constructed from the right and left stereo images. A modified cepstrum filter is applied to the patches and disparity vectors are determined by peak detection algorithm. The three-dimensional information for synthetic ages is obtained from the measured disparity and the convergent stereo camera model. It is shown that the experimental results of the proposed method for various stereo images are accurate around the fixation point like the human visual system.

Analysis of convergent looking stereo camera model (교차 시각 스테레오 카메라 모델 해석)

  • 이적식
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.10
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    • pp.50-62
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    • 1996
  • A parallel looking stereo camera was mainly used as an input sensor for digital image processing, image understanding and the extraction of 3 dimensional information. Theoretical analysis and performance evaluation are dealt in this paper for a convergent looking stereo camera model having a fixation point with the result of crossing optical axes. The quantization error, depth resolution and equidepth map due to digital pixels, and the misalignments effects of pan, tilt and roll angles are analyzed by using rhe relationship between the reference and image coordinate systems. Also horopter, epipolar lines, probability density functions of the depth error, and stereo fusion areas for the two camera models are discussed.

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Pedicular and Extrapedicular Morphometric Analysis in the Korean Population : Computed Tomographic Assessment Relevance to Pedicle and Extrapedicle Screw Fixation in the Thoracic Spine

  • Kim, Jun-Hak;Choi, Gyeong-Mi;Chang, In-Bok;Ahn, Sung-Ki;Song, Joon-Ho;Choi, Hyun-Chul
    • Journal of Korean Neurosurgical Society
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    • v.46 no.3
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    • pp.181-188
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    • 2009
  • Objective : To evaluate the anatomical parameters that must be considered when performing thoracic transpedicular or extrapedicular screw fixation. Methods : We selected 958 vertebrae (1,916 pedicles) from 98 patients for analysis. Eight parameters were measured from CT scans : the transverse outer pedicular diameter, transverse inner pedicular diameter, length, angle, chord length of the pedicles and the transverse width, angle, and chord length of the pedicle-rib units. Results : The age of the patients ranged from 21 to 82 years (mean: 48.2 years) and there were 57 men and 41 women. The narrowest transverse outer pedicular diameter was at T5 (4.4 mm). The narrowest pedicle length was at T1 (15.9 mm). For pedicle angle, T1 was 31.6 degrees, which was the most convergent angle, and it showed the tendency of the lower the level, the lesser the convergent angle. The chord length showed a horizontal pattern with similar values at all levels. For the PRU width, T5 showed a similar pattern to the pedicle width at 13.4 mm. For the PRU angle, T1 was the largest angle at 46.2 degrees and the tendency was the lower the level. the narrower the angle. For chord length, T1 was the shortest at 46.9 mm and T8 was the longest at 60.1 mm. Conclusion : When transpedicular screw fixations carried out at the mid-thoracic level, special care must be taken because there is a high chance of danger of medial wall violation. In these circumstances, extrapedicular screw fixation may be considered as an alternative treatment.

A Case of Congenital Progressive Bilateral Convergent & Divergent Strabismus with Unilateral Exophthalmus in Holstein Cattle (선천성 진행성 양측성 내외측성 사시 및 편측성 안구돌출증 홀스타인 1예)

  • Jung, Young-Hun;Hur, Tai-Young;Choe, Chang-Yong;Kang, Seog-Jin;Lee, Hyun-June;Ki, Kwang-Seok;Park, Yung-Sang;Suh, Guk-Hyun;Kim, Jong-Taek
    • Journal of Veterinary Clinics
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    • v.29 no.4
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    • pp.344-347
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    • 2012
  • Bilateral convergent strabismus with exophthalmus(BCSE) is an eye disorder affecting many cattle breeds worldwide. BCSE is the most common in cattle at various types of strabismus. Divergent strabismus is of relatively low incidence than convergent strabismus. This report is the to shown a case of convergent and divergent strabismus with unilateral in the exophthalmus in a heifer Holstein cow. A female Holstein calf born with congenital progressive divergent strabismus in right eye and convergent strabismus in left eye was tested. Ocular and blood examination, and activity were checked from the first week, 8 month, and 16 month after birth. The ocular examination includes general inspection, fixation reflex and menace response. The general inspection is checking the degree of deviation of both eyes from the normal visual axis, which was determined by the amount of sclera permanently visible in the temporal corner of the eye. The stage is divided into 4 stages depending on the degree of deviation. The right eye shown in stage 4 continues after birth and the left eye shown stage 2, stage 3 and stage 4 at 1 week, 8 month and 16 month after birth, respectively. In fixation reflex and Menace response, both eye balls showed a normal response at 1 week, 8 month and 16 month after birth. Blood count and serum chemistry test were performed, but a specific factor was not detected outside the reference range.

Verification of Secondary Electron Generated by Head Screw in Gamma Knife Using Monte Carlo N-Particle Simulation

  • Kim, Heesoo;Lee, Jeong-Woo
    • Progress in Medical Physics
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    • v.31 no.2
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    • pp.29-34
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    • 2020
  • Purpose: The interaction of various substances inserted into the human body and radiation can confirm the radiation enhancement effect. A Leksell frame inserted into the human body for gamma knife treatment will cause not only pain and inconvenience to the patient, but also additional exposure to the patient's normal tissues. In this study, we attempt to confirm the additional exposure caused by the interaction of the Leksell frame and thermoplastic mask, and 60Co used for gamma knife treatment. Methods: A 60Co energy of 1.17, 1.33 MeV is applied using Monte Carlo simulation, and fixation screws and thermoplastic mask are fabricated using aluminum and titanium alloy, and Carbon compounds. Results: Results show a dose enhancement of up to 396.27% higher compared with that without a Leksell frame and up to 391.25% in thermoplastic mask. Conclusions: Hence, appropriate treatment methods and materials must be used to reduce additional exposure to normal tissues.