Continuous average Straightness in spatial graphs

Vincent Labatut

doi:10.1093/comnet/cnx033

Multivariate spatial central limit theorems with applications to percolation and spatial graphs

The Annals of Probability ◽

10.1214/009117905000000206 ◽

2005 ◽

Vol 33 (5) ◽

pp. 1945-1991 ◽

Cited By ~ 20

Author(s):

Mathew D. Penrose

Keyword(s):

Central Limit ◽

Limit Theorems ◽

Central Limit Theorems ◽

Spatial Graphs

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EFICIÊNCIA DE DIFERENTES ELEMENTOS FILTRANTES NA PREVENÇÃO DE OBSTRUÇÃO DE GOTEJADORES

Irriga ◽

10.15809/irriga.2003v8n1p78-87 ◽

2003 ◽

Vol 8 (1) ◽

pp. 78-87 ◽

Cited By ~ 1

Author(s):

José Euclides Stipp Paterniani ◽

Marcos Eduardo Scatolini

Keyword(s):

Irrigation Water ◽

Suspended Solid ◽

Filter Element ◽

Solid Concentration ◽

Algae Removal ◽

Mesh Screen ◽

Suspended Solid Concentration ◽

E Mail ◽

Synthetic Fabric ◽

Continuous Average

EFICIÊNCIA DE DIFERENTES ELEMENTOS FILTRANTES NA PREVENÇÃO DE OBSTRUÇÃO DE GOTEJADORES José Euclides Stipp Paterniani Marcos Eduardo ScatoliniFaculdade de Engenharia Agrícola, Universidade Estadual de Campinas, Campinas, SP. CP 6011, CEP 13083-970, E-mail: [email protected] 1 RESUMO Durante ensaios para verificação de eficiência de retenção de algas em filtros de discos 120 MESH, tela 120 MESH e manta sintética não tecida, foram avaliados o grau de obstrução de gotejadores de labirinto com fluxo turbulento e vazão nominal de 4 L.h-1 e 8 L.h-1. Para determinação da obstrução causada por impurezas não retidas no meio filtrante foram avaliadas a evolução da vazão e da uniformidade estatística dos gotejadores submetidos aos diferentes meios filtrantes durante um período de 22 semanas durante 4 horas diárias e comparadas com uma parcela testemunha sem elemento filtrante. Os resultados mostraram que houve diferença significativa entre o elemento de discos, que apresentou maior uniformidade estatística, os filtros de manta e tela com valores intermediários e a testemunha que apresentou menor uniformidade estatística. No entanto, para caracterizar de maneira definida a diferença no desempenho dos elementos filtrantes, estes valores deveriam vir acompanhados de uma redução contínua na vazão média dos tratamentos, o que foi observado apenas para o elemento de tela com o gotejador de 4 L.h-1. As demais variações da uniformidade estatística foram temporais, provavelmente devido a obstruções temporárias ocasionadas por variações da concentração de sólidos suspensos na água de irrigação. UNITERMOS: Filtragem, Gotejamento, Qualidade da água. PATERNIANI, J.E.S.; SCATOLINI, M.E. EFFICIENCY OF DIFFERENT FILTER ELEMENTS TO PREVENT TRICKLE CLOGGING 2 ABSTRACT This work aimed to verify the efficiency of algae removal in disks 120 mesh, screen 120 mesh, and non woven synthetic fabric filters. It was evaluated the degree of clogging of turbulent flow drippers on 4 L.h-1 and 8 L.h-1 outflow. For blockage determination the outflow evolution and statistics uniformity (Us) of the dripper have been evaluated when submitted to different filter media over 22 weeks, 4 daily hours compared to a control without the filter element. The results indicated significant differences among the elements. The disk element presented greater statistic uniformity. The screen filter and the non woven synthetic fabric element presented intermediate values whereas the parcel with no filter element (control) presented minor statistic uniformity. However, in order to characterize performance differences among them, values should be presented along with a continuous average outflow reduction in all treatments. This pattern was observed only for the screen filter and 4 L.h-1 drippers. The statistics uniformity variation has been probably caused by temporary blockages due to variation in suspended solid concentration in irrigation water. KEYWORDS: filtration, drip irrigation, water quality.

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Robot navigation algorithms using learned spatial graphs

Robotica ◽

10.1017/s0263574700008559 ◽

1986 ◽

Vol 4 (2) ◽

pp. 93-100 ◽

Cited By ~ 54

Author(s):

S. S. Iyengar ◽

C. C. Jorgensen ◽

S. V. N. Rao ◽

C. R. Weisbin

Keyword(s):

Robot Navigation ◽

Sensor Data ◽

Two Dimensional ◽

Continuous Transition ◽

Spatial Graph ◽

Spatial Graphs ◽

Navigation Algorithms ◽

Sensor Information ◽

Navigation Planning ◽

Available Information

SUMMARYFinding optimal paths for robot navigation in a known terrain has been studied for some time but, in many important situations, a robot would be required to navigate in completely new or partially explored terrain. We propose a method of robot navigation which requires no pre-learned model, makes maximal use of available information, records and synthesizes information from multiple journeys, and contains concepts of learning that allow for continuous transition from local to global path optimality. The model of the terrain consists of a spatial graph and a Voronoi diagram. Using acquired sensor data, polygonal boundaries containing perceived obstacles shrink to approximate the actual obstacles surfaces, free space for transit is correspondingly enlarged, and additional nodes and edges are recorded based on path intersections and stop points. Navigation planning is gradually accelerated with experience since improved global map information minimizes the need for further sensor data acquisition. Our method currently assumes obstacle locations are unchanging, navigation can be successfully conducted using two-dimensional projections, and sensor information is precise.

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