Predicting Algorithm of the Polygonal Area of Collapse in the Mine Goaf Based on WebGIS

2011 ◽  
Author(s):  
Ming-Xiang He ◽  
Wen Wen ◽  
Jiu-Chuan Wei ◽  
Xin-Ming Lu
Keyword(s):  
Polygonal Area

scholarly journals R-DFS: A Coverage Path Planning Approach Based on Region Optimal Decomposition

2021 ◽  
Vol 13 (8) ◽  
pp. 1525
Author(s):  
Gang Tang ◽  
Congqiang Tang ◽  
Hao Zhou ◽  
Christophe Claramunt ◽  
Shaoyang Men
Keyword(s):  
Path Planning ◽  
Google Earth ◽  
Simulation Experiments ◽  
Minimum Width ◽  
Coverage Path Planning ◽  
Optimal Paths ◽  
Planning Approach ◽  
Polygonal Area ◽  
Aerial Vehicle ◽  
Working Distance

Most Coverage Path Planning (CPP) strategies based on the minimum width of a concave polygonal area are very likely to generate non-optimal paths with many turns. This paper introduces a CPP method based on a Region Optimal Decomposition (ROD) that overcomes this limitation when applied to the path planning of an Unmanned Aerial Vehicle (UAV) in a port environment. The principle of the approach is to first apply a ROD to a Google Earth image of a port and combining the resulting sub-regions by an improved Depth-First-Search (DFS) algorithm. Finally, a genetic algorithm determines the traversal order of all sub-regions. The simulation experiments show that the combination of ROD and improved DFS algorithm can reduce the number of turns by 4.34%, increase the coverage rate by more than 10%, and shorten the non-working distance by about 29.91%. Overall, the whole approach provides a sound solution for the CPP and operations of UAVs in port environments.

scholarly journals Analytic spherical harmonic gradients for real-time rendering with many polygonal area lights

2020 ◽  
Vol 39 (4) ◽  
Author(s):  
Lifan Wu ◽  
Guangyan Cai ◽  
Shuang Zhao ◽  
Ravi Ramamoorthi
Keyword(s):  
Real Time ◽  
Spherical Harmonic ◽  
Polygonal Area

Breeding Cycle and Behavior of the Semipalmated Sandpiper at Barrow, Alaska

The Auk ◽  
1979 ◽  
Vol 96 (1) ◽  
pp. 56-67 ◽  
Author(s):  
Shoshana Ashkenazie ◽  
Uriel N. Safriel
Keyword(s):  
Home Range ◽  
Pair Formation ◽  
Egg Laying ◽  
Breeding Cycle ◽  
Male And Female ◽  
Semipalmated Sandpiper ◽  
The Family ◽  
Polygonal Area ◽  
Calidris Pusilla ◽  
And Behavior

Abstract Pair formation of Calidris pusilla near Barrow, Alaska occurs 3-6 days after the territory is established. The pair is then engaged in nest scraping displays during 2-3 days, in which 10-12 scrapes are made by the male and examined by the female. Eventually 2-3 scrapes are lined by the female, and in one of these the first egg is laid 4-6 days after pairing. During the egg-laying period further lining is performed by the female and partial incubation takes place by both sexes. Continuous incubation commences 8 h prior to laying of the 4th egg. Male and female alternate in incubation: in the first 2 days a turn lasts 3-5 h, and the duration gradually increases up to 13-14 h during the 2nd week. Long incubation turns reduce the number of approaches to the nest and may therefore reduce the chances of it being discovered by predators. The incubating bird is intermittently engaged in egg-rolling and in camouflaging the nest by bending adjacent grass blades over its back, and is constantly alert. The off-duty bird may feed 2-3 km away from the nest. The eggs hatch after 20 days of incubation, all within 1 day. Females desert the family 2-8 days after hatching: they desert late if hatching is early, and early if hatching is late in the season. After female departure the family moves from the nesting territory, typically in a high-centered polygonal area, to establish a home range as far as 2-3 km away, often in a low-centered polygonal area. During the first 6-8 days after hatching, the male prepares each evening a scrape for night brooding. After fledging, the male and young join wandering flocks.

Real‐time Indirect Illumination of Emissive Inhomogeneous Volumes using Layered Polygonal Area Lights

2019 ◽  
Vol 38 (7) ◽  
pp. 449-460
Author(s):  
Takahiro Kuge ◽  
Tatsuya Yatagawa ◽  
Shigeo Morishima
Keyword(s):  
Real Time ◽  
Polygonal Area ◽  
Indirect Illumination

Polygonal Area of Prosthesis Support with Straight and Tilted Dental Implants in Edentulous Maxillae

2016 ◽  
Vol 29 (3) ◽  
pp. 245-252 ◽  
Author(s):  
Stefan Wentaschek ◽  
Karl Lehmann ◽  
Herbert Scheller ◽  
Gernot Weibrich ◽  
Nikolaus Behneke
Keyword(s):  
Dental Implants ◽  
Polygonal Area

Lattice Points and Polygonal Area

1967 ◽  
Vol 74 (10) ◽  
pp. 1195 ◽  
Author(s):  
Ivan Niven ◽  
H. S. Zuckerman
Keyword(s):  
Lattice Points ◽  
Polygonal Area

Ultrastructural study of the embryonic and larval shell of Anodonta cygnea

1989 ◽  
Vol 67 (7) ◽  
pp. 1659-1664 ◽  
Author(s):  
F. Castilho ◽  
J. Machado ◽  
M. L. Reis ◽  
C. Sá
Keyword(s):  
Ultrastructural Study ◽  
Internal Surface ◽  
Light Polarization ◽  
Larval Shell ◽  
Shell Formation ◽  
X Ray Diffraction ◽  
Anodonta Cygnea ◽  
X Ray ◽  
Polygonal Area ◽  
The Matrix

An ultrastructural study of the embryonic and larval shell of Anodonta cygnea was carried out by light, polarization, and scanning electron microscopy, and X-ray diffraction analysis. A thin outer layer (cuticle), composed of β-keratin fibrils organized in parallel rows and enveloped by chitin material, was observed. The hooks, spines, and teeth are constituted by cuticular formations only. A calcareous inner layer presenting convergent prismatic monocrystals mainly of aragonite, which form prismatic structures around the pores and inside of irregular polygonal border lines, was also shown. Two clearly differentiated calcareous valves were already observed on very young embryos. The valvular pores totally covered by the cuticle may be involved in the metabolic cell exchange by penetrating cytoplasmatic extensions of the mantle cells. The irregular polygonal configuration observed on the internal surface of young decalcified cuticles supports the hypothesis of a role for the matrix as a regulator of shell formation, inducing the prismatic organization of the calcareous layer. Shell mineralization from the border lines to the center of each polygonal area may occur.

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