• 제목/요약/키워드: Bilateral Symmetry

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조명 변화에 강인한 얼굴 검출을 위한 좌우대칭 평균화 기법 (A Bilateral Symmetry Average Method for Robust Face Detection against Illumination Variation)

  • 조치영;김수환
    • 게임&엔터테인먼트 논문지
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    • 제2권2호
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    • pp.45-50
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    • 2006
  • 형판 정합 기반의 얼굴 검출 시스템에서 획득된 이미지에 대한 명암 정규화 및 영상 보정을 위해 히스토그램 평활화나 로그 변환 등을 사용한다. 이 방법은 조명 변화에 의해 발생한 이미지의 부분 명암 왜곡에는 효과적이지 못하다는 것이 알려져 있다. 본 논문에서는 부분적 명암 왜곡에 매우 효과적인 영상 보정을 수행하는 좌우대칭 평균화 기법을 제시한다. 실험 결과 이 기법은 기존의 방식보다 매우 효율적인 검출 성능을 보일 뿐만 아니라 얼굴 후보의 개수도 현저하게 감소하는 것으로 나타났다.

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3차원 가상모형을 이용한 하악 제2소구치 교두 변이 대칭성에 대한 융복합적 분석 - 전북지역 일부 대학생을 중심으로 (Convergence analysis of cusp variation symmetry of the mandibular second premolars using 3-dimensional virtual models - Focusing on college students in Jeollabuk-do)

  • 남신은
    • 디지털융복합연구
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    • 제20권2호
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    • pp.317-323
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    • 2022
  • 본 연구는 3차원 가상모형을 이용하여 하악 제2소구치 교두 변이 양상을 정성적으로 분석하고, 교두 변이에 따른 치아 표면적의 정량적 분석과 함께 좌·우측 대칭성을 분석하고자 하였다. 127개의 하악 제2소구치 가상치아를 준비한 후, RapidForm2004(INUS technology INC, Seoul, Korea)을 이용하여 각 교두의 절대적/상대적 단면적, 전체 치관 단면적, 교합면의 중심구 형태 등을 분석하였다. 통계방법은 Independent t-test, Kruskal-Wallis test 및 교차분석을 시행하였다. 연구 결과, 중심구의 형태는 양측간 높은 대칭성을 보였다. 좌측에서 U 형태이면 우측도 100.0% U 형태를 나타냈으며, 나머지 H 형태와 Y 형태는 각각 73.7%, 78.9% 비율로 양측간 동일한 중심구 형태를 나타냈다(p<.001). 본 연구에서 얻은 결과는 CAM/CAM을 이용한 보철물 제작 시 참고자료로 활용이 가능할 것이며, 향후 맹출 직후의 하악 제2소구치를 포함한 더 많은 샘플을 대상으로 한 후속연구가 이루어지기를 기대한다.

뇌 CT 영상의 대칭성을 고려한 관심영역 중심의 효율적인 의료영상 압축 (An Efficient Medical Image Compression Considering Brain CT Images with Bilateral Symmetry)

  • 정재성;이창훈
    • 한국인터넷방송통신학회논문지
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    • 제12권5호
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    • pp.39-54
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    • 2012
  • 오늘날 의료정보화 수준향상과 디지털 병원화의 흐름에 따라 PACS는 의료기관의 핵심 인프라 중 하나로 자리매김하였다. 이와 함께 생산되는 디지털 의료영상의 종류 및 의료영상 데이터가 양적으로 급증하고 있으며, 이는 의료영상 데이터의 효과적인 보관을 위한 의료영상 압축을 중요한 요소로 부각시킨다. 현재 의료영상에 관한 사실상의 표준인 DICOM 규격에서는 의료영상 압축을 위하여 무손실 압축기법인 RLE를 명시하고 있으나, 무손실 범용 압축기법인 RLE는 인체의 대칭성을 가지는 많은 의료영상에 적용하면 높은 압축율 기대하기 힘들다. 이 논문에서는 다양한 의료영상 중 대칭 특성을 크게 내포하는 뇌 CT 영상을 대상으로 하여 영상 내 관심영역을 검출하고 대칭특성에 따라 영상의 픽셀 값을 재코딩하는 전처리 하고 영상을 압축하는 기법을 제안한다. 실험에 의하면, 제안한 기법은 RLE 압축과 영상 내 관심영역을 검출하지 않고 압축할 때와 비교하여 높은 압축률을 보인다.

조명 변화에 강인한 얼굴 검출을 위한 좌우대칭 평균화와 단순회귀분석 보정기법 (Bilateral Symmetry Averaging and Simple Regression Analysis for Robust Face Detection Against Illumination Variation)

  • 조치영;김수환
    • 한국콘텐츠학회논문지
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    • 제6권12호
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    • pp.21-28
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    • 2006
  • 형판 정합 기반의 얼굴 검출 시스템에서 획득된 이미지에 대한 명암 정규화 및 영상 보정을 위해 보통 히스토그램 평활화 등을 사용한다. 이 방법은 조명 변화에 의해 발생한 이미지의 부분 명암 왜곡에는 효과적이지 못하다는 것이 알려져 있다. 본 논문에서는 다양한 방향의 조명에 의한 명암 왜곡을 효과적으로 보정하는 전처리 기법을 제시한다. 이 기법은 얼굴의 좌우대칭성을 이용한 좌우대칭 평균화와 단순회귀분석을 이용한 세로 방향 명암 보정을 결합한 것이다. 실험 결과 이 기법은 기존의 방식보다 높은 검출성능을 보일 뿐만 아니라 얼굴의 후보 개수도 현저하게 감소하는 것으로 나타났다.

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횡복직근 유리피판술에 의한 양측 유방 재건 (Bilateral Breast Reconstruction with Free TRAM Flaps)

  • 안희창
    • Archives of Reconstructive Microsurgery
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    • 제9권2호
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    • pp.127-133
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    • 2000
  • Free TRAM flap is now increasingly suggested to patients requiring breast reconstruction after the mastectomy. This study is to introduce the experiences of bilateral free TRAM flaps for reconstruction of bilateral breasts and to suggest the way of getting the more satisfactory results. A total of 6 breasts were reconstructed in 3 patients using bilateral free TRAM flaps immediately following the mastectomy. Average operative time for bilateral breast reconstruction was 8 hours comparing to 6.5 hours for unilateral breast reconstruction. Partial or total flap loss did not occur in 6 flaps. Abdomen was repaired directly with muscle and fascia sparing technique without necessity of mesh graft. There was no complication in donor site like abdominal hernia. Bilateral breast reconstruction can achieve exceptionally good aesthetic result with low complication if it is performed with skillful technique and experience. The reason for this is that fairly good symmetry usually is obtained in the initial surgery and in most cases only minimal additional surgery is required to achieve a satisfactory aesthetic result. The one disadvantage of bilateral reconstruction with autologous tissue is the length of the surgical procedure. Although the initial bilateral breast reconstruction can be a long, tedious procedure if free flaps are used, it must be a valuable treatment option for bilaterally mastectomized patients.

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체간 안정화 운동 후 경직형 양하지 뇌성마비 아동의 정적, 동적 족저압의 변화 (Change of Static and Dynamic Foot Pressure after Trunk Stabilization Exercises in Children with Spastic Diplegic Cerebral Palsy)

  • 염주노;임재길
    • The Journal of Korean Physical Therapy
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    • 제26권4호
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    • pp.274-279
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    • 2014
  • Purpose: The aim of this study was to determine the change of static and dynamic foot pressure on trunk stabilization exercise in children with spastic diplegic cerebral palsy. Methods: This study examined five male children participants ages 10~14 years old with spastic diplegic cerebral palsy. All subjects participated in a 6-week sling exercise program for trunk stabilization; the exercise was performed three times per week and each session lasted 50 minutes. The subjects were measured for static and dynamic foot pressure and bilateral symmetry of both feet before and after the trunk stabilization exercise. Results: The static foot pressure increased significantly before and after the trunk stabilization exercise (left foot: before $0.41{\pm}0.02%BW/cm^2$ after $0.79{\pm}0.02%BW/cm^2$, right foot: before $0.14{\pm}0.03%BW/cm^2$, after $0.43{\pm}0.44%BW/cm^2$) (p<0.05) and bilateral symmetry of both feet increased (before $0.27{\pm}0.18%BW/cm^2$, after $0.37{\pm}0.05%BW/cm^2$) with more weight shift on left foot than right foot, but was not statistically significant (p>0.05). The dynamic foot pressure increased (left foot: before $2.58{\pm}0.44%BW/cm^2$, after $3.40{\pm}0.31%BW/cm^2$, right foot: before $2.75{\pm}0.19%BW/cm^2$, after $3.26{\pm}0.18%BW/cm^2$) with more weight shift on right foot than left foot, but was not statistically significant (p>0.05), and bilateral symmetry of both feet decreased (before $0.31{\pm}0.36%BW/cm^2$, after $0.13{\pm}0.20%BW/cm^2$) (p<0.05). Conclusion: The findings of this study indicated that the trunk stabilization exercise has a positive impact on static and dynamic foot pressure in children with spastic diplegic cerebral palsy.

바른 자세 유지를 위한 상의류 디자인 연구 -대칭의 원리를 중심으로- (T-shirt Design for Maintaining Proper Posture -Focusing on the Principle of Symmetry-)

  • 한금화;김한나;최윤미;노주현
    • 한국의류학회지
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    • 제47권2호
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    • pp.337-352
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    • 2023
  • This study develops a t-shirt design that align bones and balance muscles in order to maintain proper posture using the basic concepts of symmetry. First, theoretical and 3D design studies, existing literature on proper and improper posture, and the basic concepts of symmetry are studied to create the design. Next, the 3D design process applies bilateral, rotational, and scaling symmetries to design the inner lines from the basic application of symmetry. A two-stage design process is used, whereby the strain map and pressure points are analyzed using the CLO virtual clothing software, and the most effective design is determined through virtual testing. The results show that the Y+)( and X+― design, which combines the position and type of inner lines, is the most effective for posture correction and maintenance. Overall, this study helps create a theoretical and practical basis for exploring and understanding basic lines appropriate for the human body, and subsequently, for developing various products that maintain posture more accurately and precisely.

트레드밀에서 뒤로걷기 훈련이 경직성 양하지 뇌성마비 아동의 보행에 미치는 영향: 사전 연구 (The Effectiveness of Backward Gait Training on the Treadmill in Children With Spastic Diplegic Cerebral Palsy: A Pilot Study)

  • 김성경;류영욱;김원호
    • 한국전문물리치료학회지
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    • 제19권3호
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    • pp.81-90
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    • 2012
  • The aim of the current study was to assess the effectiveness of backward gait training on the treadmill in patients with spastic diplegic cerebral palsy (CP). Twelve patients with spastic diplegic CP participated in the study. An 8-week course of backward gait training was administered to the subjects for 3 days per week. Pre-intervention and post-intervention assessments of temporal-spatial gait parameters, the symmetry of the bilateral lower extremity weight bearing, and gross motor function were analyzed using motion analysis system, force plate, and Gross Motor Function Measurement (GMFM). There were significant improvements (p<.05) in the measures of both step length and right stance phase time. Joint kinematics showed increase in right hip abduction in initial contact and terminal swing, right hip external rotation and knee flexion in mid-swing, left ankle dorsiflexion in initial contact and terminal swing (p<.05). The symmetry of the bilateral lower extremity weight bearing and GMFM also significantly increased (p<.05). These findings indicate that backward gait training using a treadmill is beneficial for patients with spastic diplegic CP.

관절오목 이형성이 있는 개의 내측 슬개골 탈구 수술 전, 후의 운동역학적 보상적 보행 변화 (증례보고) (Compensatory Change of a Dog with Glenoid Dysplasia in Kinetic Gait Analysis before and after Reconstruction of Medial Patellar Luxation (Case report))

  • 이신호;서정현;차유리
    • 대한물리치료과학회지
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    • 제31권1호
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    • pp.46-52
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    • 2024
  • Background: This study aims to investigate compensatory strategy in a dog with glenoid dysplasia using kinetic gait analysis before and after reconstruction of medial patellar luxation. Design: Case report Method: On the platform, gait analysis was evaluated for a dog with congenital luxation and bilateral medial patellar luxation (MPL). A dog was evaluated for maximal vertical force (MVF), body load distribution (BLD), and symmetry index (SI), including the left forelimb with congenital luxation before MPL surgery, 15 days of surgery, and 40 days of surgery. Result:: In the comparison between the preoperative and the 15 days of surgery, the MVF of the bilateral forelimbs, especially in the non-affected forelimbs, increased, and the SI also increased. For BLD, the maximum load distribution increased, but the total load distribution decreased. In the comparison of 15 days and 40 days of surgery, MVF and BLD increased, and SI decreased on 40days of surgery. Conclusions: In a dog, the shift in weight load to the non-affected side occurs all the limbs, affecting the peak vertical force, weight load distribution, and symmetry index.

Relationship between Hip Medial Rotation Range of Motion and Weight Distribution in Patients with Low Back Pain

  • Kim, Sang-Kyu;Kim, Won-Bok;Ryu, Young-Uk
    • 대한물리의학회지
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    • 제9권3호
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    • pp.279-284
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    • 2014
  • PURPOSE: This study intended to verify whether there was actual correlation between weight-bearing asymmetry and a limitation in hip joint rotation range in patients with low back pain. METHODS: Thirty five low back pain patients voluntarily participated this study. For each participant, hip joint medial rotation symmetry rate and the weight-bearing symmetry rate were calculated. The correlation between the two variables was investigated. RESULTS: A decrease in the left hip joint medial rotation range of motion (ROM) was observed more often than a reduction in the right hip joint medial rotation ROM. However, similar number between right and left side was observed in ground reaction force more weighted. The coefficient between the passive hip joint medial rotation symmetry rate and the weight loading symmetry ratio was -0.19 (p < 0.05). CONCLUSION: The present study demonstrated a weak correlation between the hip joint medial rotation ROM and the weight distribution of both feet. Such result suggests that careful evaluation by separating each element is needed in treating patients with low back pain. Future research should take into account asymmetric alignment and abnormal movement in different joints of the body as well as asymmetry in the bilateral hip joint rotation and the unilateral weight supporting posture.