• 제목/요약/키워드: crest angle

검색결과 65건 처리시간 0.023초

민감도분석을 통한 지진하중을 받는 CFRD 정상부 침하량 예측 (Estimation of Settlement on the Crest of CFRD Subjected to Earthquake Loading Using Sensitivity Analysis)

  • 하익수
    • 한국지반공학회논문집
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    • 제23권1호
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    • pp.39-49
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    • 2007
  • 본 연구의 목적은 수치해석을 이용한 정량적 민감도분석으로부터 지진하중을 받는 CFRD 정상부 침하량 변화의 주 영향인자를 찾고, 주 영향인자 변화에 따른 침하량의 변화양상을 고찰하고, 이로부터 지진하중을 받는 CFRD 정상부 침하량을 근사적으로 추정하는 방법을 제안하는 데 있다. 대형삼축압축시험으로부터 얻어진 사력재료 물성을 통계 분석하여 사력재료 물성 통계특성값을 산정하고, 산정된 통계특성값을 이용하여 작성된 27개 해석단면에 대해 해석조건을 달리한(2개 지진파, 각 지진파별 2가지 가속도 크기) 총 108개 CFRD 해석단면에 대한 동적수치해석을 수행, 그 결과를 이용한 정량적 민감도분석을 수행하였다. 민감도분석 결과, 지진하중 작용 시 CFRD 정상부 침하량은 입력 물성 중 전적으로 사력재료의 전단탄성계수에 의존하는 것으로 나타났고 점착력과 마찰각의 영향은 미미하였다. 민감도분석 결과와 전단탄성계수 변화에 따른CFRD 동적해석 결과로부터, 사력재료의 전단탄성계수와 간단한 댐 정보를 이용하여 지진하중 작용시 CFRD 정상부 침하량을 근사적으로 추정하는 방법을 제안하였다.

지형 경사를 고려한 다중빔 음향측심기(300 kHz) 후방산란 자료 처리에 관한 연구 (Backscatter Data Processing of Multibeam Echo-sounder (300 kHz) Considering the Actual Bottom Slope)

  • 김태헌;이정민;박수철
    • 자원환경지질
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    • 제48권5호
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    • pp.379-390
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    • 2015
  • 다중빔 음향 측심기의 후방산란 음압은 해저면 퇴적상뿐만 아니라 지형 경사로 인해 변화된 음파의 실제 입사각에 의해서도 강도가 달라지므로 후방산란 음압 분석에 앞서, 지형 경사를 고려한 정밀한 자료처리가 필요하다. 본 논문은 지형 경사에 따른 실제 입사각 및 입사면적에 대한 후방산란 자료처리 방법과 경사 지형에서의 후방산란 특징에 대해 기술하였다. 황해 동부의 사퇴분포 해역에 위치한 연구지역은 수심이 46~55 m의 범위를 보이며, 다양한 지형 경사를 가지는 대규모 dune들이 발달되어 있다. 대규모 dune들의 경사는 대부분 $1{\sim}3^{\circ}$ 내외로 완만하지만 등성이에서는 경사가 $5{\sim}15^{\circ}$로 가파른 특징을 보인다. 후방산란 자료처리 결과, 지형 경사를 고려하지 않은 경우에는 등성이에서 음압이 -34~-23 dB의 범위를 보인다. 반면, 본 연구 방법으로 지형 경사를 고려한 경우에는 같은 지역에서 음압이 -32~-25 dB 범위로써 음압 변동 폭이 완화되는 효과를 보였다. 또한, 후방산란 영상에서도 등성이에서 나타나는 강하고 약한 이상 음압 분포가 개선되어, 본 연구의 후방산란 자료처리 방법이 지형 경사로 인한 음압 변화를 효과적으로 보정하는 것으로 확인되었다.

체간 굴곡-신전운동 후 체간 각 부위 별 시상면 높이변화에 대한 조사 (A study of variation level for each region changed in trunk at sagittal plane after Trunk Flexion-Extension Exercise)

  • 김근조;이규리;정병옥
    • 대한정형도수물리치료학회지
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    • 제14권2호
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    • pp.1-15
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    • 2008
  • Purpose : This survey was to investigate on the effect of each region changed in trunk through sagittal plane after Trunk Flexion-Extension Exercise. Methods : 18 students of Gimcheon College participated in this study for the period of July 9-30, 2007. Analyzed factor were 1) degree of pain 2) presence of Gillet test and 3) difference of right-left for 7 landmark region in trunk applying I.B.S.-2000 after Trunk Flexion - Extension Exercise. We used the SPSS $PC^+$ program for classifying into analysis of frequency, $x^2$-test, t-test and Simple Linear Regression analysis test. Results: Followings are concluded For degree of pain, 13(72.2%) of students answered "No pain" after Trunk Flexion-Extension Exercise and in the result 4 more students decreased the pain. In the Gillet test, 14(77.8%) of students answered "positive" after Trunk Flexion-Extension Exercise and in the result 4 more students increased mobility of Sacroiliac joint. In the differences of right-left for 7 landmark region in trunk by B.M.I. scale, Slim type was decreased both Acromion(0.45mm), both Iliac crest(0.44mm), and both ASIS(0.31mm) to anterior plane, Normal type was decreased both inferior angle of Scapular(0.02mm), both L4-5(0.07mm), and both PSIS(0.09mm) to posterior plane Fatness type was decrease both Acromion(0.05mm), both ASIS(0.05mm) to anterior plane. In the differences of right-left for 7 landmark region in trunk for degree of pain No pain group was decreased both Acromion(0.17mm), both Nipple(0.25mm) to anterior plane and both PSIS(0.13mm) to posterior plane Pain group was decreased both Acromion(0.04mm), both Iliac creast(0.03mm) to anterior plane and both inferior angle of Scapular(0.18mm) both PSIS(0.13mm) to posterior plane. In the difference of right-left for 7 landmark region in trunk for each of the exercises, Both iliac crest(0.1mm), both ASIS(0.12mm) to anterior plane were decreased after Flexion Trunk Exercise. Both acromion(0.27mm) to anterior plane, both inferior angle of scapular(0.14mm) and both PSIS(0.12mm) to posterior plane were decreased after Extension Trunk Exercise. Each of the exercises, The both inferior angle of Scapular showed high scores($0.65{\pm}0.23$) at Trunk Extension Exercise group and there was statistical significance between Trunk Flexion Exercise group and Extension exercise group(t :-2.502, p < 0.05). 7. At Pre-exercise group, Both inferior angle of Scapular showed low scores($0.23{\pm}8.27$) at Trunk Extension Exercise group and there was statistical significance between Pre- Exercise group and Trunk Extension Exercise group(t :-2.5430, p<0.05). Conclusion : The simple linear regression analysis was presented at Acromion(-0.243), L4-5(-0.753), PSIS(0.576) and there was statistical significance in BMI scale(p<0.01).

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Polyetheretherketone Cage with Demineralized Bone Matrix Can Replace Iliac Crest Autografts for Anterior Cervical Discectomy and Fusion in Subaxial Cervical Spine Injuries

  • Kim, Soo-Han;Lee, Jung-Kil;Jang, Jae-Won;Park, Hyun-Woong;Hur, Hyuk
    • Journal of Korean Neurosurgical Society
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    • 제60권2호
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    • pp.211-219
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    • 2017
  • Objective : This study aimed to compare the clinical and radiologic outcomes of patients with subaxial cervical injury who underwent anterior cervical discectomy and fusion (ACDF) with autologous iliac bone graft or polyetheretherketone (PEEK) cages using demineralized bone matrix (DBM). Methods : From January 2005 to December 2010, 70 patients who underwent one-level ACDF with plate fixation for post-traumatic subaxial cervical spinal injury in a single institution were retrospectively investigated. Autologous iliac crest grafts were used in 33 patients (Group I), whereas 37 patients underwent ACDF using a PEEK cage filled with DBM (Group II). Plain radiographs were used to assess bone fusion, interbody height (IBH), segmental angle (SA), overall cervical sagittal alignment (CSA, C2-7 angle), and development of adjacent segmental degeneration (ASD). Clinical outcome was assessed using a visual analog scale (VAS) for pain and Frankel grade. Results : The mean follow-up duration for patients in Group I and Group II was 28.9 and 25.4 months, respectively. All patients from both groups achieved solid fusion during the follow-up period. The IBH and SA of the fused segment and CSA in Group II were better maintained during the follow-up period. Nine patients in Group I and two patients in Group II developed radiologic ASD. There were no statistically significant differences in the VAS score and Frankel grade between the groups. Conclusion : This study showed that PEEK cage filled with DBM, and plate fixation is at least as safe and effective as ACDF using autograft, with good maintenance of cervical alignment. With advantages such as no donor site morbidity and no graft-related complications, PEEK cage filled with DBM, and plate fixation provide a promising surgical option for treating traumatic subaxial cervical spine injuries.

Correlation of Radiographic and Patient Assessment of Spine Following Correction of Nonstructural Component in Juvenile Idiopathic Scoliosis

  • Lee, Jin Gyeong;Yun, Young Cheol;Jo, Won Jae;Seog, Tae Yong;Yoon, Yong-Soon
    • Annals of Rehabilitation Medicine
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    • 제42권6호
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    • pp.863-871
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    • 2018
  • Objective To evaluate the association between progression of curvature of scoliosis, and correction for functional component in patients with juvenile idiopathic scoliosis (JIS). Methods We retrospectively reviewed medical data of patients prescribed custom molded foot orthosis (FO) to correct inequality of RCSPA (resting calcaneal stance position angle), and chose 52 patients (26 females, 26 males) with Cobb angle ${\geq}10^{\circ}$ in radiology and uneven pelvic level at iliac crest by different RCSPA (${\geq}3^{\circ}$) as a factor of functional scoliosis. They had different hump angle ${\geq}5^{\circ}$ in forward bending test, for idiopathic scoliosis component. Their mean age and mean period of wearing FO were $79.5{\pm}10.6months$ and $18.6{\pm}0.70months$. Results Cobb angle was reduced from $22.03^{\circ}{\pm}4.39^{\circ}$ initially to $18.86^{\circ}{\pm}7.53^{\circ}$ after wearing FO. Pelvis height difference and RCSPA difference, were reduced from $1.07{\pm}0.25cm$ initially to $0.60{\pm}0.36$, and from $4.25^{\circ}{\pm}0.71^{\circ}$ initially to $1.71^{\circ}{\pm}0.75^{\circ}$ (p<0.01). Cobb angle improved most in 9 months. However, there was no significant improvement for those with more than $25^{\circ}$ of Cobb angle initially. Mean Cobb angle improved in all age groups, but patients less than 6 years had clinically significant improvement of more than $5^{\circ}$. Conclusion JIS can have functional components, which should be identified and managed. Foot orthosis is useful in correcting functional factors, in the case of pelvic inequality caused by different RCSPA, for patients with juvenile idiopathic scoliosis.

충돌 제트에 의해 형성되는 액막의 두께 특성에 관한 연구 (Interferometric Measurements of the Thickness Distribution of the Liquid Sheet Formed by Two Impinging Jets)

  • 추연준;강보선
    • 대한기계학회논문집B
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    • 제24권2호
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    • pp.214-223
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    • 2000
  • In this research, a study on the characteristics of the liquid sheet formed by two impinging jets is presented. Using the interference phenomena of light, the thickness of the liquid sheet, which seems to heavily affect the size of the droplets, is measured and compared with existing theoretical modelings. Thinner liquid sheet is produced with larger impinging angle, smaller orifice diameter, and higher azimuthal angle but the jet velocity doesn't affect the thickness. More viscous liquid produces thicker liquid sheet. The theoretical modelings predict the same trend as the experiments but the thickness values are overestimated at low azimuthal angles. This difference is gradually decreased as the azimuthal angle is increased: The breakup mechanism of the droplets from the liquid sheet is visualized by a high speed camera. The crest around the edge of the liquid sheet is protruded with the accumulation of liquid at the end of protuberance, which contracts into a spherical shape and then becomes detached when the stem breaks down, producing large droplets with a few small size of satellites.

지진하중을 받는 CFRD 정상부 변위에 영향을 미치는 사력재료 입력물성에 대한 민감도분석 (Sensitivity Analysis of Rockfill Input Parameters Influencing Crest Displacement of CFRD Subjected to Earthquake Loading)

  • 하익수
    • 한국지진공학회논문집
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    • 제11권1호
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    • pp.1-9
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    • 2007
  • 본 연구는 지진하중을 받는 콘크리트 표면차수벽형 석괴댐(CFRD)의 정상부 변위에 대한 사력재료 주요물성의 민감도를 정량적으로 분석하는데 그 목적이 있다. 이를 위해 현재 운영 중인 국내 CFRD 형식의 D댐에 대해 2가지 지진파, 각 지진파에 대해 2가지 설계진도, 사력재료에 대해 수행된 대형삼축압축시험 결과로부터 얻어진 물성값을 조합하여 만든 물성값이 다른 해석단면 27개를 작성, 총 108개 해석단면에 대한 동적 수치해석을 수행, 그 결과를 이용한 대역적 민감도분석을 수행하였다. 민감도분석 결과, 지진하중 작용 시 댐 정상부 침하량은 입력지진의 종류와 설계진도 크기에 상관없이 절대적으로 사력재료 전단탄성계수에만 영향을 받았으며 댐 정상부 횡변위의 경우에는, 사력재료 전단탄성계수의 영향이 크나 그 영향의 정도는 침하량에 미치는 정도에 비해 상대적으로 작으며, 침하량과는 달리 지진파의 종류와 크기에 따라 차이를 보였다. 본 연구결과에 한해 사력재료의 마찰각은 지진하중에 의한 CFRD 정상부 변위에는 전혀 영향을 주지 않는 것으로 나타났다.

골반교정에 대한 국내 임상 연구 동향 (An Overview of Clinical Studies on Pelvic Correction in Korea)

  • 백지유;배재룡;안훈모;이재흥
    • 대한의료기공학회지
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    • 제20권1호
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    • pp.118-147
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    • 2020
  • Objective : The purpose of this study is to understand trends of pelvic correction therapy in Korea and to assist research activities on pelvic correction therapy. Also, this study selected and presented indicators for measuring pelvic slope to help ensure consistent studies with uniform indicators in future studies related to pelvic correction. Methods : The following keywords "골반", "골반 교정", "골반 변위" "Pelvic correction" were searched on three specialized search sites (RISS, NAI, DBpia). Trends in pelvic correction therapy were analyzed through the selected researches suitable among these searched researches in an overview format. Results : 1. A total of 7,806 studies were searched and a total of 268 studies were finally selected. 2. Studies began in 1977 and have been actively studied until recently, with 35 studies in 2017 being the most recent trend since 2000. 3. In the results according to the Main Field of Research, the 'Arts and Kinesiology'(113, 42.16%) and 'Medicine and Pharmacy'(103, 38.43%) were the most in order. To the Middle Field, the 'Kinesiology was the largest with 96(35.82%) studies. 4. In the results according to the study design, 'Pre-Post Test(PPT)' was the largest with 107 studies. 5. In the results according to the Intervention, 'Exercise' was the largest with 165 studies, of which 'Pilates' and 'Yoga' in 'Training' was the largest. 6. Among the evaluation method, the 'Pelvic Index' was used 146 times, followed by 'Spinal Alignment (99)', 'Other Joints (93)', and 'Kinetic Specialized Measurement Test (56)'. 7. Among the evaluation methods, the pelvic slope measurement indicators were PT (58), PH (48), Pelvic Torsion (40), Iliac Crest (38), ASIS-PSIS distance/angle (27), and Pelvic Width (I.W., I.L., S.W) (25) in order. 8. The journals that published the most researches were KJSS(Korean Alliance For Health, Physical Education, Recreation, And Dance;9), and JKPT(Korean Physical Therapy;9). Among the University, the Graduate School of Silla University published the most papers (12). 9. The author who published the most studies were Seungjin Park(3), the co-authors were Hoseong Lee, Gideok Park, Seongsu Bae(3), and the Thesis-Director Gyeongok Lee(7). Conclusions : 1. Studies on pelvic correction treatment continue to increase every year. 2. The main academic field of pelvic correction is 'Sports', 'Physical Therapy', and 'Medical Science'. 3. The most chosen research design method in the study on pelvic correction treatment was 'Pre-Post Test(PPT)', primarily as an intermediary, Pilates and yoga during exercise therapy, and then Chiropractic during handcraft were used as multiple frequencies. 4. Among the various measurement method indicators of pelvic correction previously used, multiple frequency was taken up in the order of PT, PH, Pelvic Torsion, iliac crest, ASIS-PSIS distance/angle, and pelvic width (I.W.,I.L.,S.W). Typically, measurements through "ASIS-PSIS angle" are recommended and are considered as the most rational in clinical trials.

하악관에 관한 방사선학적 연구 (A RADIOGRAPHIC STUDY ON THE MANDIBULAR CANAL)

  • 조성은;김재덕
    • 치과방사선
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    • 제21권2호
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    • pp.307-316
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    • 1991
  • The purpose of this study is to improve the availabilities of radiographic technics as diagnostic method related to mandibular canal in dental clinic. For this study 12 dry mandibles were used and 12 orthopantomograms were taken for measuring the gonial angle and the angle of mandibular canal to inferior border of mandible. 12 sites located between the 1st premolar to the 3rd molar region of 3dry mandibles were selected randomly, for measuring the vertical image magnification rates on three films; intraoral film, orthopantomogram, and computed tomogram, respectively and the thickness of cortical bone, and for observing bucco-lingually and supero-inferiorly location of the mandibular canal. The acquired results were as follows: 1. The means of the gonial angle and the angle of mandibular canal to inferior border of mandible were 123.9° and 143.5° And the two angles of dry mandible in alveolar crest stage were greater than in alveolar socket stage. 2. The vertical image length on intraoral film by paralleling technic was magnified by 3.07% on the average, the length on orthopantomogram by 18.49%, and the length on computed tomogram by 0.27%. 3. Observation of the bucco-lingually positional relationship of the mandibular canal was impossible by occlusal projection with the cross section technic and intraoral standard projection with the Clack's rule, however, possible by computed tomogram. 4. The thickness of the cortical bone of mandible was thickest in inferior border, and thicker by 6.59% at buccal side than at lingual side.

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변수심에서의 항주파 파형 예측 및 FLOW-3D에 의한 검증 (Prediction of ship wave Crests on Varying Water Depths and Verification by FLOW-3D)

  • 이병욱;이창훈;김용재;고광오
    • 대한토목학회논문집
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    • 제33권4호
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    • pp.1447-1454
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    • 2013
  • 본 연구에서 선형분산관계식의 순환관계를 이용하여 Kelvin (1887)의 이론을 확장함으로써 심해뿐만 아니라 중간수심까지 적용 가능한 항주파의 파형을 예측하는 이론식을 개발하였다. 본 이론식은 일정수심 뿐만 아니라 완경사의 변수심에도 적용 가능하다. 본 연구의 해석해를 검증하기 위하여 FLOW-3D모형을 이용하여 수치실험을 수행하였다. 수치해와 이론해를 비교해본 결과, 본 연구의 이론해는 일정수심 뿐만 아니라 변수심에서도 항주파의 전파 양상을 잘 재현하였다. 평면 경사면 위로 배가 해안선과 나란하게 전파하는 경우 항주파의 전파 양상이 비대칭이 되었다. 즉, 수심이 얕은 곳은 굴절로 인하여 파향선이 해안선과 나란한 경향이 있고, 수심이 깊은 곳은 역굴절로 인하여 파향선이 해안선에 수직인 경향이 있었다.