A Novel NURBS Surface Motion Command Generator

2006 ◽  
Author(s):  
Chung-Wei Cheng ◽  
Wen-Peng Tseng
Keyword(s):  
Nurbs Surface ◽  
Surface Motion

scholarly journals Distributed Scatterer InSAR Reveals Surface Motion of the Ancient Chaoshan Residence Cluster in the Lianjiang Plain, China

2019 ◽  
Vol 11 (2) ◽  
pp. 166 ◽  
Author(s):  
Yuzhou Liu ◽  
Peifeng Ma ◽  
Hui Lin ◽  
Weixi Wang ◽  
Guoqiang Shi
Keyword(s):  
Time Series ◽  
Deformation Rate ◽  
First Generation ◽  
Groundwater Resources ◽  
Potential Threat ◽  
Groundwater Exploitation ◽  
Surface Motion ◽  
Elastic Rebound ◽  
Surface Patterns ◽  
Change Dynamic

The Lianjiang Plain in China and ancient villages distributed within the plain are under the potential threat of surface motion change, but no effective monitoring strategy currently exists. Distributed Scatterer InSAR (DSInSAR) provides a new high-resolution method for the precise detection of surface motion change. In contrast to the first-generation of time-series InSAR methodology, the distributed scatterer-based method focuses both on pointwise targets with high phase stability and distributed targets with moderate coherence, the latter of which is more suitable for the comprehensive environment of the Lianjiang Plain. In this paper, we present the first study of surface motion change detection in the Lianjiang Plain, China. Two data stacks, including 54 and 29 images from Sentinel-1A adjacent orbits, are used to retrieve time-series surface motion changes for the Lianjiang Plain from 2015 to 2018. The consistency of measurement has been cross-validated between adjacent orbit results with a statistically significant determination coefficient of 0.92. The temporal evolution of representative measuring points indicates three subzones with varied surface patterns: Eastern Puning (Zone A) in a slight elastic rebound phase with a moderate deformation rate (0–40 mm/yr), Chaonan (Zone B) in a substantial subsidence phase with a strong deformation rate (−140–0 mm/yr), and Chaoyang (Zone C) in a homogeneous and stable situation (−10–10 mm/yr). The spatial distribution of these zones suggests a combined change dynamic and a strong concordance of factors impacting surface motion change. Human activities, especially groundwater exploitation, dominate the subsidence pattern, and natural conditions act as a supplementary inducement by providing a hazard-prone environment. The qualitative and quantitative analysis of spatial and temporal details in this study provides a basis for systematic surface motion monitoring, cultural heritage protection and groundwater resources management.

Motion periodicity and bifurcation of a wave excited hopping ball

2019 ◽  
Vol 475 (2228) ◽  
pp. 20190137
Author(s):  
Gaurang Ruhela ◽  
Anirvan DasGupta
Keyword(s):  
Wave Amplitude ◽  
Harmonic Wave ◽  
Inelastic Collisions ◽  
Loss Of Stability ◽  
Elastic Surface ◽  
Minimum Frequency ◽  
Surface Motion ◽  
Return Map ◽  
Ball Problem ◽  
Subsequent Loss

We consider the problem of a hopping ball excited by a travelling harmonic wave on an elastic surface. The ball, considered as a particle, is assumed to interact with the surface through inelastic collisions. The surface motion due to the wave induces a horizontal drift in the ball. The problem is treated analytically under certain approximations. The phase space of the hopping motion is captured by constructing a phase-velocity return map. The fixed points of the return map and its compositions represent periodic hopping solutions. The linear stability of the obtained periodic solution is studied in detail. The minimum frequency for the onset of periodic hops, and the subsequent loss of stability at the bifurcation frequency, have been determined analytically. Interestingly, for small values of wave amplitude, the analytical solutions reveal striking similarities with the results of the classical bouncing ball problem.

Optical doppler velocimeter for surface motion measurement

1972 ◽  
Vol 17 (6) ◽  
pp. 1551-1553
Author(s):  
N. N. Vorob'eva ◽  
E. I. Zubarev ◽  
V. M. Kulybin ◽  
B. S. Rinkevichyus
Keyword(s):  
Motion Measurement ◽  
Surface Motion

scholarly journals Lung surface deformation prediction from spirometry measurement and chest wall surface motion

2016 ◽  
Vol 43 (10) ◽  
pp. 5493-5502 ◽  
Author(s):  
Joubin Nasehi Tehrani ◽  
Alistair McEwan ◽  
Jing Wang
Keyword(s):  
Chest Wall ◽  
Surface Deformation ◽  
Wall Surface ◽  
Deformation Prediction ◽  
Surface Motion

Effects of g jitter on free-surface motion in a cavity

1995 ◽  
Vol 32 (1) ◽  
pp. 177-183 ◽  
Author(s):  
Y. Kamotani ◽  
L. Chao ◽  
S. Ostrach ◽  
H. Zhang
Keyword(s):  
Free Surface ◽  
Surface Motion

NURBS Surface Reconstruction From a Large Set of Image and World Data Points

1993 ◽  
Author(s):  
Vassilios E. Theodoracatos ◽  
Vasudeva Bobba
Keyword(s):  
Least Squares ◽  
Vision System ◽  
Physical Object ◽  
Free Form ◽  
Approximation Technique ◽  
Global Coordinate System ◽  
Large Set ◽  
Affine Invariant ◽  
Nurbs Surface ◽  
Data Points

Abstract In this paper an approach is presented for the generation of a NURBS (Non-Uniform Rational B-splines) surface from a large set of 3D data points. The main advantage of NURBS surface representation is the ability to analytically describe both, precise quadratic primitives and free-form curves and surfaces. An existing three dimensional laser-based vision system is used to obtain the spatial point coordinates of an object surface with respect to a global coordinate system. The least-squares approximation technique is applied in both the image and world space of the digitized physical object to calculate the homogeneous vector and the control net of the NURBS surface. A new non-uniform knot vectorization process is developed based on five data parametrization techniques including four existing techniques, viz., uniform, chord length, centripetal, and affine invariant angle and a new technique based on surface area developed in this study. Least-squares error distribution and surface interrogation are used to evaluate the quality of surface fairness for a minimum number of NURBS control points.

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