• Title/Summary/Keyword: and symmetry

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Contour-Based Partial Object Recognition Of Elliptical Objects Using Symmetry (대칭특성을 이용한 타원형 객체의 외형기반 부분인식에 관한 연구)

  • Cho June-Suh
    • The KIPS Transactions:PartB
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    • v.13B no.2 s.105
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    • pp.115-120
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    • 2006
  • In This Paper, We Propose The Method To Reconstruct And Estimate Partially Occluded Elliptical Objects In Images From Overlapping And Cutting. We Present The Robust Method For Recognizing Partially Occluded Objects Based On Symmetry Properties, Which Is Based On The Contours Of Elliptical Objects. A Proposed Method Provides Simple Techniques To Reconstruct Occluded Regions Via A Region Copy Using The Symmetry Axis Within An Object. Based On The Estimated Parameters For Partially Occluded Objects, We Perform Object Recognition On The Classifier. Since A Proposed Method Relies On Reconstruction Of The Object Based On The Symmetry Properties Rather Than Statistical Estimates, It Has Proven To Be Remarkably Robust In Recognizing Partially Occluded Objects In The Presence Of Scale Changes, Object Pose, And Rotated Objects With Occlusion, Even Though h Proposed Method Has Minor Limitations Of Object Poses.

ON HORIZONTAL LIGHTLIKE HYPERSURFACES OF ROBERTSON-WALKER SPACETIMES

  • Liu, Ximin;Pan, Quanxiang
    • Communications of the Korean Mathematical Society
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    • v.30 no.2
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    • pp.109-121
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    • 2015
  • In this paper, we investigate horizontal lightlike hypersurfaces of Robertson-Walker spacetimes. Some results involving the unique existence of the screen distribution and the symmetry of the induced Ricci curvature tensor of horizontal lightlike hypersurfaces are presented. We also obtain some properties concerning the symmetry and the parallelism of the second fundamental forms of such lightlike hypersurfaces.

Test of Symmetry against Near Type III Positive Biasedness

  • Oh, Myong-Sik
    • Proceedings of the Korean Statistical Society Conference
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    • 2003.10a
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    • pp.63-68
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    • 2003
  • One of the widely accepted assumptions in many statistical problem is that the underlying distribution is symmetric. Though a large number of nonparametric test are available in the literature for this problem, very few procedures focuses on the distributional structure when the symmetry assumption is rejected. Yanagimoto and Sibuya (1972) provided the various types of asymmetric distributional structure, positive biasedness, namely. In this paper we consider the test of symmetry against several new positive biasedness restrictions which are stronger than Yanagimoto and Sibuya's type II bias but weaker than type IV (III) bias.

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Conservation Laws and Symmetry of Differential Equations -stories about E. Noether's Theorem- (보존률과 미분방정식의 대칭성 -뇌터의 정리를 중심으로-)

  • Han, Chong-Kyu
    • Journal for History of Mathematics
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    • v.31 no.5
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    • pp.211-222
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    • 2018
  • This paper surveys the theory of symmetry group of differential equations. A proof of the simplest version of the Noether's theorem on conservation laws has been presented with examples in the classical mechanics. As a new approach to the conservation laws the theory of characteristic cohomology due to S. H. Wang and others has been presented.

SYMMETRY OF SPECIAL COMPOSITION OPERATORS ON THE HARDY SPACE

  • Young-Bok Chung
    • Honam Mathematical Journal
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    • v.46 no.1
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    • pp.60-69
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    • 2024
  • We consider a special orthonormal basis for the Hardy space of the unit disc to compute the matrix representations of the composition operators with respect to the basis particulary associated to two symbols which are the inverse and the origin symmetry of the Riemann self map in the unit disc, and then we find a certain symmetry of the matrices.

Effects of Unilateral Static Stretching on Flexibility and Symmetry of Lower Leg, and Temporal Gait Variables in Gait Asymmetry People (편측 정적스트레칭이 보행 비대칭자의 하지 유연성과 대칭성 및 시간적 보행 변인에 미치는 영향)

  • Kwon, Young-Ae;Yoo, Kyung-Tae;Lee, Ho-Seong
    • Journal of the Korean Society of Physical Medicine
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    • v.15 no.3
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    • pp.89-98
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    • 2020
  • PURPOSE: This study investigated the effects of unilateral static stretching on the flexibility and symmetry of the lower leg, and temporal gait variables in gait asymmetry people. METHODS: Twenty gait asymmetry people were divided into a unilateral static stretching group (USG, n = 10) and control group (CON, n = 10). The USG performed unilateral static stretching for 60 minutes, three times a week, and eight weeks. The flexibility of the lower leg (SR), and symmetry (BR), and temporal gait variables (Step length; SL, gait speed; GS) were measured before, after four and eight weeks of unilateral static stretching. Moreover, SI (symmetry index; SI) was calculated from the measured SL value. Statistical analyses were conducted using one-way ANOVA and two-way ANOVA with repeated measures, a paired t-test, and multiple comparisons according to Scheffe. RESULTS: SR and BR in the dominant and non-dominant side, and GS were increased significantly at USG after eight-weeks compared to before unilateral static stretching (p < .05). The difference in BR in the dominant and non-dominant side, and step length (SI) decreased significantly at USG after eight-weeks compared to before unilateral static stretching (p < .05). CONCLUSION: Unilateral static stretching improves the flexibility and symmetry of the lower leg, and temporal gait variables in gait asymmetry people.

EQUIVALENCE CONDITIONS OF SYMMETRY PROPERTIES IN LIGHTLIKE HYPERSURFACES OF INDEFINITE KENMOTSU MANIFOLDS

  • Lungiambudila, Oscar;Massamba, Fortune;Tossa, Joel
    • Bulletin of the Korean Mathematical Society
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    • v.53 no.4
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    • pp.1259-1280
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    • 2016
  • The paper deals with lightlike hypersurfaces which are locally symmetric, semi-symmetric and Ricci semi-symmetric in indefinite Kenmotsu manifold having constant $\bar{\phi}$-holomorphic sectional curvature c. We obtain that these hypersurfaces are totally goedesic under certain conditions. The non-existence condition of locally symmetric lightlike hyper-surfaces are given. Some Theorems of specific lightlike hypersurfaces are established. We prove, under a certain condition, that in lightlike hyper-surfaces of an indefinite Kenmotsu space form, tangent to the structure vector field, the parallel, semi-parallel, local symmetry, semi-symmetry and Ricci semi-symmetry notions are equivalent.

STATISTICAL VALIDATION OF SYMMETRY IN ESTIMATION OF GROUNDWATER CONTAMINANT CONCENTRATIONS

  • Cho, Choon-Kyung;Sungkwon Kang
    • Journal of applied mathematics & informatics
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    • v.13 no.1_2
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    • pp.335-351
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    • 2003
  • Spatial distribution of groundwater contaminant concentration has special characteristics such as approximate symmetric profile, for example, in the transversal direction to groundwater flow direction, a certain ratio in directional propagation distances, etc. To obtain a geophysically appropriate semivariogram which is a key factor in estimation of groundwater contaminant concentration at desired locations, these special characteristics should be considered. In this paper, a method for finding appropriate symmetric axes is introduced. Statistical analyses for the choices of symmetric axes and mathematical models for semivariograrns are performed. After implementing symmetry, the corresponding semivariograrns, kriging variances, and final estimated results show significant improvement compared with those obtained by conventional approaches which usually do not account for symmetry.

A Comparision of the Twisting of Extrusion of Elliptical Shape with that of S shape from Round Billet by DEFORM-3DTM Software (원형빌렛으로부터 타원단면 및 S단면 가진제품의 압출가공의 DEFORM-3DTM에 의 한 비틀림 해석 비교)

  • 김진훈;김한봉;진인태
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.03a
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    • pp.136-139
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    • 1997
  • Applications of commercial software DEFORM-3DTM for 3-D simulation in extrusion process are developed for the analysis of twisting of extruded products. Because the elliptical shape has at least one line symmetry, the twisting is not occured during the extrusion. But, the results of extrusion simulation of the elliptical shape show that the twisted boundary of the die surface makes the material inside die surface rotate with the constant angular velocity. Otherwise, the simulation results of the S shaped product show that the twisting can be occured by the only 180$^{\circ}$rotation symmetry of S shape without no line symmetry and show that the angular velocity increases by the only 180$^{\circ}$rotation symmetry without no twisted die surface between on the die entrance section and on the die exit section. The results of the analysis show that the angular velocity of the extruded product changes with die length and friction condition.

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Effects of d-wave symmetry on the critical current of YBCO step-edge Josephson junction

  • Hwang, Yun-Seok;Moon, Sunk-Yung;Ahn, Jong-Rok;Lee, Soon-Gul;Kim, Jin-Tae
    • 한국초전도학회:학술대회논문집
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    • v.10
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    • pp.99-102
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    • 2000
  • We have studied the effects of d-wave symmetry on the critical current of YBa$_2$Cu$_3$O$_7$ step-edge Josephson junctions. The critical current along various misorientation angle was measured and analyzed with the concept of grain-boundary junctions with d-wave symmetry. Experimental results of c-oriented YBCO step-edge junctions with various in-plane misorientation angles were qualitatively in good agreement with the theory. The out-of-plane misorientation angle is usually formed between two grains with the c axes perpendicular to each other and is normally not controllable.

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