• Title/Summary/Keyword: medial axis

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The kinematics analysis of Discus throwing (원반던지기의 운동학적 분석)

  • Kim, Jong-In;Sun, Jae-Bok
    • Korean Journal of Applied Biomechanics
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    • v.13 no.2
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    • pp.29-47
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    • 2003
  • This study is to analyze the kinematic variables in release motion of discuss throwing. For the matter, 5 people from the national team and collegiate discuss throwing in the year 2001 were chosen as the subjects and two S-VHS video cameras set in 60frames/sec were used for recording their motions. Coordinated raw positions data through digitizing are smoothing by butter-worth 's low-pass filtering method at a cut off frequency 6.0Hz. and the direct linear transformation(DLT) method was employed to obtain 3-D position coordinates. The conclusions were as follows; 1. The better record players showed the shorter approach time in the last support phase. 2. In the displacement CG, the better record players showed the shorter displacement in medial-lateral direction, and the longer displacement in horizontal direction. In the motion, the COG showed longer displacement vertical direction. 3. The better record players showed the faster horizontal velocity than vertical velocity in the release. 4. The better record players showed to take the posture of vertical axis in the release.

A FINITE ELEMENT AND STRAIN GAUGE ANALYSIS ON THE DISPLACEMENT OF CRANIOFACIAL COMPLEX WITH CERVICAL HEADGEAR (경부고정(頸部固定) headgear 사용시(使用時) 안면두개골(顔面頭蓋骨)의 변위(變位)에 관(關)한 장력계측법(張力計測法) 및 유한요소법적(有限要素法的) 연구(硏究))

  • Kim, Hyun-Soon;Nahm, Dong-Seok
    • The korean journal of orthodontics
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    • v.17 no.2
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    • pp.185-200
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    • 1987
  • This paper was undertaken to observe the displacement of craniofacial complex with cervical headgear and to compare narrowing or widening effect of palate by use of contraction or expansion face-bow, respectively. The 3-dimensional finite element method(FEM) was used for a mathematical model composed of 597 nodes and 790 elements and an electrical resistance strain gauge investigation was performed to validate the finite element model. The outer bow of cervical headgear was adjusted to be placed below the occlusal plane by $25^{\circ}$ and met the midsagittal plane by $40^{\circ}$, and was loaded 1kg on each right and left hook toward posterior direction. The results were as follows 1. Generally, the maxillary teeth and facial bone were displaced in posterior, medial and downward direction. 2. It was the maxillary 2nd bicuspid that moved bodily. 3. The craniofacial complex rotated in a clockwise direction around the rotating axis which lay from the most posterior and lowest point connecting nasal crest of maxillary bone and vomer, progressively toward a more posterior, lateral and upward direction, anterior and upper area of pterygomaxillary fissure, base of medial pterygoid plate and laterally to the contact area of zygomatic arch with squamous part of temporal bone. 4. No contraction effect was observed by contraction face-bow when compared to the standard face-bow. 5. In case of expansion face-bow, the areas of maxillary 2nd bicuspid, molars and palate were expanded remarkably.

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A Study on Dose Distribution around Fletcher-Suit Colpostat Containing $^{137}Cs$ Source ($^{137}Cs$ 선원을 내포한 Fletcher-Suit Colpostat 주위의 선량분포에 관한 연구)

  • Kang Wee-Saing
    • Radiation Oncology Journal
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    • v.6 no.2
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    • pp.263-268
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    • 1988
  • This paper presents dose distributions in water around Fletcher-Suit colpostat containing $^{137}Cs$ tube, and shielding effect of Internal lead shield. Using ready packed film, author measured dose distribution in water around the colpostat containing cesium source. Nine sheets of films on one side of the colpostat are packed with acryl frames cut out so as to fill water, and irradiated in water by cesium source in the colpostat. Dose distributions on transverse plane and upper plane 0.5cm from upper surface of the colpostat were measured. Shielding effect was greater in upper medial direction than in lower medial direction. And that was the greatest around $30^{\circ}$ from the axis of the colpostat on upper side and around $50^{\circ}$on lower side. In the region 7cm from the center of the colpostat, shielding efficiency was 0.23 to 0.35 on the lower $50^{\circ}$ and 0.26 to 0.42 on the upper $30^{\circ}$, and decreased with increase of distance.

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Analysis of Sports Biomechanical Variable on the Motions of Left and Right Spikes of Volleyball (배구 레프트 스파이크와 라이트 스파이크 동작에 대한 운동역학적 변인 비교 분석)

  • Cho, Ju-Hang;Ju, Myung-Duck
    • Korean Journal of Applied Biomechanics
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    • v.16 no.4
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    • pp.125-134
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    • 2006
  • The purpose of this study was to analyze the Biomechanical elements by looking at the differences on the motions of the right and left spikes of right-handed offense volleyball players, using 3D image analysis and force platform. For that purpose, spike motions of six male university volleyball players were recorded three times each using two 16mm high speed cameras and the speed of recording was set at 60 frames/sec. The coordinated raw data was leveled as 6Hz using low pass filtering method and the calculation of 3D coordinates was done by using a DLT (Direct Linear Transformation) method. Also KWON 3D program was used to analyze the variables. Through the experiments and research, the following results were found: That is, in case of the right spike, the required time from the toss to the impact, which affected the success rate of offense showed as longer and on the take-off, the exact timing to touch the ball was longer because the pace between right and left feet was wider, and also after the jump, the distance between the feet indicated shorter, than the left. In addition, the degree of somersault and horizontal adduction of shoulder joint was smaller and the degree of medial rotation of shoulder joint showed bigger than the left, so it indicated that it was not centered on the body, but by the arm with an axis of shoulder using a swing motion. After the impact, the speed of the ball indicated slower compared to the left spike.

Effects of Electroacupuncture on the excitability in Medial Vestibular Nuclei of Rats (흰쥐의 내측 전정신경핵 흥분성에 대한 전침자극의 효과)

  • Kim, Jae-Hyo;Lee, Sung-Ho;Sohn, In-Chul;Kim, Young-Sun;Kim, Min-Sun
    • Korean Journal of Acupuncture
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    • v.26 no.3
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    • pp.27-42
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    • 2009
  • Objectives : The vestibular system detects head movement and serve to regulate and maintain the equilibrium and orientation of the body. It is known that the vestibular imbalance leads to vestibular symptoms such as nausea, vomiting, vertigo and postural disturbance. The objectives of the present study were to examine a modification of the dynamic activities of medial vestibular nucleus (MVN) neurons following electroacupuncture (EA) of GB43 (Hyepgye). Methods : In Sprague-Dawley rats weighing $250{\sim}300g$, dynamic responses induced by sinusoidal whole body rotation about vertical axis at 0.2 Hz were observed in MVN of rats during EA of GB43 (Hyepgye) with 0.2 ms, 40 Hz and $600{\pm}200{\mu}A$. Also, expression of cFos protein was observed 2 hours after EA for 30 mins. Results : In dynamic response of vestibular neuron, the excitatory or inhibitory responses of gain were predominant in the ipsilateral MVN neurons during EA but not predominant in the contralateral MVN. Most neurons showing decreased gain were classified to inhibitory responses of spontaneous firing discharge during EA and ones showing increased gain were classified to excitatory response of spontaneous firing discharge during EA. Also, EA of the left GB43 (Hyepgye) for 30 mins produced the expression of cFos protein in MVN, inferior olive (IO) and solitary tract nuclei (SOL). Spatial expressions of cFos protein were predominant in the contralateral MVN, ipsilateral IO and bilateral SOL. Conclusion : These results suggest that the excitability of MVN neurons was influenced by EA of GB43 (Hyepgye) and EA may be related to the convergence on MVN.

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Efficient Geometric Model Reconstruction using Contour Lines (외곽선을 이용한 효율적인 기하모델 재구성 기법)

  • Jung Hoe Sang;Kwon Koo Joo;Shin Byeong-Seok
    • Journal of KIISE:Computer Systems and Theory
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    • v.32 no.8
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    • pp.418-425
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    • 2005
  • 3D surface reconstruction is to make the original geometry of 3D objects from 2D geometric information. Barequet's algorithm is well known and most widely used in surface reconstruction. It tiles matched regions first, then triangulates clefts using dynamic programming. However it takes considerably long processing time while manipulating complex model. Our method tiles a simple region that does not have branches along minimally distant vertex pairs at once. When there are branches, our method divides contour lines into a simple region and clefts. We propose a fast and simple method that calculates medial axes using a minimum distance in cleft region. Experimental results show that our method can produce accurate models than the previous method within short time.

Functional Connections of the Vestibulo-spino-adrenal Axis in the Control of Blood Pressure Via the Vestibulosympathetic Reflex in Conscious Rats

  • Lu, Huan-Jun;Li, Mei-Han;Li, Mei-Zhi;Park, Sang Eon;Kim, Min Sun;Jin, Yuan-Zhe;Park, Byung Rim
    • The Korean Journal of Physiology and Pharmacology
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    • v.19 no.5
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    • pp.427-434
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    • 2015
  • Significant evidence supports the role of the vestibular system in the regulation of blood pressure during postural movements. In the present study, the role of the vestibulo-spino-adrenal (VSA) axis in the modulation of blood pressure via the vestibulosympathetic reflex was clarified by immunohistochemical and enzyme immunoassay methods in conscious rats with sinoaortic denervation. Expression of c-Fos protein in the intermediolateral cell column of the middle thoracic spinal regions and blood epinephrine levels were investigated, following microinjection of glutamate receptor agonists or antagonists into the medial vestibular nucleus (MVN) and/or sodium nitroprusside (SNP)-induced hypotension. Both microinjection of glutamate receptor agonists (NMDA and AMPA) into the MVN or rostral ventrolateral medullary nucleus (RVLM) and SNP-induced hypotension led to increased number of c-Fos positive neurons in the intermediolateral cell column of the middle thoracic spinal regions and increased blood epinephrine levels. Pretreatment with microinjection of glutamate receptor antagonists (MK-801 and CNQX) into the MVN or RVLM prevented the increased number of c-Fos positive neurons resulting from SNP-induced hypotension, and reversed the increased blood epinephrine levels. These results indicate that the VSA axis may be a key component of the pathway used by the vestibulosympathetic reflex to maintain blood pressure during postural movements.

A STUDY ON THE POSITION OF CONDYLAR HEAD ON COMPUTED TOMOGRAM (전산화 단층 촬영법을 이용한 하악과두의 위치에 관한 연구)

  • Lee Jong Bok;Kim Jae Duk
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.17 no.1
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    • pp.151-162
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    • 1987
  • The author obtained the computed tomograms around the condylar head from 10 normal subjects and 5 patients having clicking condylar head from 10 normal subjects and 5 patients having clicking sound or limitation of mouth opening by using a Hitachi-W 500. And then. the author had the axial analysis of condyle position and sagittal analysis of that after sagittal reformation on centric occlusion and 18㎜ interincisal opening. Transcranial view and submentovertex view were taken and compared with computed tomographic view. The obtained results were as follows: 1. Median angle of long axis of condylar head was 17 degrees on centric occlusion and the angles of long axis of both condylar heads were reduced symmetrically on 18㎜ interincisal opening in normal group. however. in the patient group, the affected side of condyle heads showed greater change in the angle on 18㎜ interincisal opening. 2. In the patient group, the condyle head of affected side was located superiorly to that of normal side on centric occlusion and the discrepancy of condular positional height was increased after 18㎜ interincisal opening. 3. The distances from medial pole of condylar head to triangular fossa of temporal bone were same on both right and left side in normal group, however, in the patient group, the distance of affected side was wider than that of opposite side on centric occusion and became narrower than the opposite side on 18㎜ interincisal opening. 4. The distances of posterior joint space were same on both right and left side. The distance t lateral pole 1/3 of condyle head was similar to that on transcranial view on centric occlusion in normal group. 5. The distances of posterior joint space were narrower in patient group than in normal group. 6. Conclusively, the affected condylar head of patient showed postero-latero-superior displacement on centric occlusion and larger range of rotational movement on 18㎜ interincisal opening.

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The petiole anatomy of the genus Spiraea L. (Rosaceae) in Korea (한국산 조팝나무속(Spiraea L. 장미과)의 엽병 해부)

  • Lee, Jeong-Ho;Kwon, Oh-Woung;Jang, Tae-Soo;Roh, Hee-Seon;Hong, Suk-Pyo
    • Korean Journal of Plant Taxonomy
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    • v.40 no.1
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    • pp.16-26
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    • 2010
  • The petiole anatomy of three sections (sects. Calospira, Chamaedryon, and Spiraria) in the genus Spiraea (Rosaceae), which are distributed/cultivated in Korea, was studied and described in details. The vascular bundle system of the distal, medial, and proximal parts of the petiole were studied using LM with the aim of documenting any differences in vascular anatomy. Significant variation of anatomical characters was found in petiole shape (dichotomy, lens or subcircular in outline), presence of two distinct lateral wings, the thickness of epidermis, number of vascular bundles, length of ventral axis, length of dorsiventral axis, width of median vascular bundle, and length of median vascular bundle. All features were compared and we concluded that petiole anatomical characters can be useful for providing diagnostic features to distinguish the studied taxa. A key for identifying the Spiraea taxa in Korea based on their petiole anatomical characters is also provided.

MHN Filter-based Brush Stroke Generation for Painterly Rendering (회화적 렌더링을 위한 MHN 필터 기반 브러시 스트로크 생성기법)

  • Seo, Sang-Hyun;Yoon, Kyung-Hyun
    • Journal of Korea Multimedia Society
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    • v.9 no.8
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    • pp.1045-1053
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    • 2006
  • We introduce a new method of painterly rendering. Instead of using the gradient direction of the source image to generate a brush stroke, we extract regions that can be drawn in one stroke using MHN filtering followed by identification of connected components, and make a brush stroke from each, based on an approximation to the medial axis. This method results in realistic-looking brush strokes of varying width that have an irregular directions where necessary.

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