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Time-Varying Fuzzy Contour Trees [article]

Anna-Pia Lohfink, Frederike Gartzky, Florian Wetzels, Luisa Vollmer, Christoph Garth
2021 arXiv   pre-print
We apply time-varying Fuzzy Contour Trees to different real-world data sets and demonstrate their usefulness.  ...  The resulting time-varying Fuzzy Contour Trees allow the comparison of multiple time steps that are not required to be consecutive.  ...  Also different interactive tools for the analysis of time varying contour trees and iso-contours have been developed: An interactive exploration tool for split/merge and contour trees for different time  ... 
arXiv:2107.12682v1 fatcat:copuyl7ygzbwzla62cnvgzmoo4

Applying Manifold Learning to Plotting Approximate Contour Trees

S. Takahashi, I. Fujishiro, M. Okada
2009 IEEE Transactions on Visualization and Computer Graphics  
Several sophisticated algorithms have been proposed for constructing contour trees while they often complicate the software implementation especially for higher-dimensional cases such as time-varying volumes  ...  volumes and their time-varying behaviors.  ...  Haruhisa Ishida and Jun Kobayashi helped us implement an early version of the prototype system. We also thank anonymous reviewers for their valuable comments. This work has been partially sup-  ... 
doi:10.1109/tvcg.2009.119 pmid:19834188 fatcat:2o53o5xggfbm5ngio2x7idboie

Data Parallel Hypersweeps for in Situ Topological Analysis

Petar Hristov, Gunther H. Weber, Hamish A. Carr, Oliver Rubel, James P. Ahrens
2020 2020 IEEE 10th Symposium on Large Data Analysis and Visualization (LDAV)  
The contour tree is a tool for understanding the topological structure of a scalar field.  ...  Recent work has built efficient contour tree algorithms for shared memory parallel computation, driven by the need to analyze large data sets in situ while the simulation is running.  ...  Furthermore (as pointed out by a reviewer) there are many practical situations, such as time varying domains or ensemble runs, where multiple contour trees need to be computed.  ... 
doi:10.1109/ldav51489.2020.00008 fatcat:au3zyvn5gnf2bn6ewv6yw34cji

Joint Contour Nets

Hamish Carr, David Duke
2014 IEEE Transactions on Visualization and Computer Graphics  
Contour Trees and Reeb Graphs are firmly embedded in scientific visualization for analysing univariate (scalar) fields.  ...  We generalize this analysis to multivariate fields with a data structure called the Joint Contour Net that quantizes the variation of multiple variables simultaneously.  ...  We expect that many of the techniques that work for the contour tree and Reeb graph will then extend to the JCN.  ... 
doi:10.1109/tvcg.2013.269 pmid:26357364 fatcat:tpbn4cppj5e57dci5zai7ihjsi

Task-based augmented merge trees with Fibonacci heaps

Charles Gueunet, Pierre Fortin, Julien Jomier, Julien Tierny
2017 2017 IEEE 7th Symposium on Large Data Analysis and Visualization (LDAV)  
In the context of augmented contour tree computation, we show that a direct usage of our merge tree procedure also results in superior time performance overall, both in sequential and parallel.  ...  We report performance numbers that compare our approach to reference sequential and multi-threaded implementations for the computation of augmented merge and contour trees.  ...  implementations, both for augmented merge and contour tree computations.  ... 
doi:10.1109/ldav.2017.8231846 dblp:conf/ldav/GueunetFJT17 fatcat:caf6x3vh5ff2xmca4xaftfkqei

Task-based Augmented Contour Trees with Fibonacci Heaps [article]

Charles Gueunet, J Jomier, J Tierny
2019 arXiv   pre-print
We report performance numbers that compare our approach to reference sequential and multi-threaded implementations for the computation of augmented merge and contour trees.  ...  We also introduce a new parallel algorithm for the combination of these two trees into the output global contour tree.  ...  As for the merge tree, the sequential times vary across data sets due to the output sensitivity of the algorithm.  ... 
arXiv:1902.04805v1 fatcat:vld6jh7iv5gi3jw7qxgkrm4h4a

Contour forests: Fast multi-threaded augmented contour trees

Charles Gueunet, Pierre Fortin, Julien Jomier
2016 2016 IEEE 6th Symposium on Large Data Analysis and Visualization (LDAV)  
We report performance numbers that compare our approach to a reference sequential implementation for the computation of augmented contour trees.  ...  In contrast to previous multi-threaded algorithms, our technique computes the augmented contour tree.  ...  Since augmented contour trees store the destination of each vertex into the tree, it is possible to retrieve in constant time the homologous arc a j from the adjacent tree C ( f ) j which contains v.  ... 
doi:10.1109/ldav.2016.7874333 dblp:conf/ldav/GueunetFJ16 fatcat:fficrt5765cdhh5pfslb62nrki

Task-based Augmented Contour Trees with Fibonacci Heaps

Charles Gueunet, Pierre Fortin, Julien Tierny, Julien Jomier
2019 IEEE Transactions on Parallel and Distributed Systems  
As for the merge tree, the sequential times vary across data sets due to the output sensitivity of the algorithm.  ...  Contour Tree performance results Tab. VI details execution times for our contour tree computation.  ... 
doi:10.1109/tpds.2019.2898436 fatcat:acggevv3xfclngp5vdohszxk7a

Isocontour based Visualization of Time-varying Scalar Fields [chapter]

Ajith Mascarenhas, Jack Snoeyink
2009 Mathematics and Visualization  
In this paper we survey isocontour based visualization techniques for time-varying scalar fields.  ...  Time-varying scalar fields are produced by measurements or simulation of physical processes over time, and must be interpreted with the assistance of computational tools.  ...  a correspondence between arcs of the contour tree at t with arcs of the contour tree at t + 1.  ... 
doi:10.1007/b106657_3 fatcat:nrwen6mzlvbh5izwlb4bimjk3m

Time-varying contour topology

B.-S. Sohn, Chandrajit Bajaj
2006 IEEE Transactions on Visualization and Computer Graphics  
In this paper, we extend all the benefits of the contour tree to time-varying data visualization.  ...  We define temporal correspondence of contour components, and describe an algorithm to compute the correspondence information in time dependent contour trees.  ...  Now, the problem is to implement the function ψ t and φ t . We use correspondence information in time dependent contour trees to compute ψt(C t k ) and φ t (C t k ).  ... 
doi:10.1109/tvcg.2006.16 pmid:16382604 pmcid:PMC2703823 fatcat:hncjbawy3bhsddp5gh3r3mznha

Performance Assessment of Erosion Remediation Measures and Proposal of The Best Management Practices for Erosion Control in Sebeya Catchment, Rwanda

Félicien Majoro, Umaru Garba Wali, Omar Munyaneza, François-Xavier Naramabuye, Concilie Mukamwambali
2020 Rwanda Journal of Engineering Science Technology and Environment  
Finally, soil erosion control measures including agro-forestry, terraces, mulching, tree planting, contour bunds, vegetative measures for slopes and buffer zones, check dams, riverbanks stabilization were  ...  proposed and recommended to be implemented in Sebeya catchment.  ...  0-6%; Areas of low risk of erosion have the slope varying between 6-16%; Areas of medium risk of erosion have the slope varying between 16-40%; Areas of high risk of erosion have the slope varying between  ... 
doi:10.4314/rjeste.v3i2.4 fatcat:oudg4vx7ozgrregtwjuovoz3ra

Hybrid Data-Parallel Contour Tree Computation [article]

Hamish Carr, Christopher Sewell, Li-Ta Lo, James Ahrens
2016 Computer Graphics and Visual Computing (CGVC)  
We report the first data-parallel algorithm for computing the fully augmented contour tree, using a quantised computation model.  ...  While topological analysis tools such as the contour tree and Morse-Smale complex are now well established, there is still a shortage of efficient parallel algorithms for their computation, in particular  ...  One of the principal mathematical tools is the contour tree or Reeb graph, which summarises the development of contours in the data set as the isovalue varies.  ... 
doi:10.2312/cgvc.20161299 dblp:conf/tpcg/CarrSLA16 fatcat:lunbxv2udbbptmfrjg4p3cai7q

Maintaining Reeb Graphs of Triangulated 2-Manifolds

Pankaj K. Agarwal, Kyle Fox, Abhinandan Nath, Marc Herbstritt
2018 Foundations of Software Technology and Theoretical Computer Science  
We present a kinetic data structure (KDS) for maintaining the Reeb graph R of h as the heights of M's vertices vary continuously with time.  ...  Each event is processed in O(log 2 n) time, and the total size of our KDS is O(gn). The KDS can be extended to maintain an augmented Reeb graph as well.  ...  Time varying Reeb graph We use the same model for the time varying function as the one in [2] .  ... 
doi:10.4230/lipics.fsttcs.2017.8 dblp:conf/fsttcs/AgarwalFN17 fatcat:vxn7kszevvdojet42czo7v5ljy

Multiscale Symmetry Detection in Scalar Fields by Clustering Contours

Dilip Mathew Thomas, Vijay Natarajan
2014 IEEE Transactions on Visualization and Computer Graphics  
Our approach combines the two by utilizing the contour tree for segmenting the data and the descriptor space for determining transformation invariance.  ...  In this paper, we present a novel representation of contours with the aim of studying the similarity relationship between the contours.  ...  The time taken for computing contour tree is denoted by t ct , generating contours by t cg , and computing contour descriptors by t cd .  ... 
doi:10.1109/tvcg.2014.2346332 pmid:26356956 fatcat:i64qkjh6i5cypoekicwk3s5fta

The Topological Effects of Smoothing

S. Shafii, S. E. Dillard, M. Hlawitschka, B. Hamann
2012 IEEE Transactions on Visualization and Computer Graphics  
This feature can be implemented via an interactive contour tree interface.  ...  An area of correspondence is caused by overlapping regions related to contours between a contour tree in time step t and another contour tree from time step t +1.  ... 
doi:10.1109/tvcg.2011.74 pmid:21519107 fatcat:v22p6hxhtnad5ntbjrvl7av6ee
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