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Incidence Geometries and the Pass Complexity of Semi-Streaming Set Cover [article]

Amit Chakrabarti, Anthony Wirth
2015 arXiv   pre-print
For each p > 1, we give a very simple deterministic algorithm that makes p passes over the input stream and returns an appropriately certified (p+1)n^1/(p+1)-approximation to the optimum set cover.  ...  Set cover, over a universe of size n, may be modelled as a data-streaming problem, where the m sets that comprise the instance are to be read one by one.  ...  Acknowledgment The second author is grateful to Andrew McGregor for discussions about some recent work.  ... 
arXiv:1507.04645v1 fatcat:jhfqgkv2dvd2nhclfwmljuytza

Segment-based tetrahedral meshing and rendering

Ralf Sondershaus, Wolfgang Straßer
2006 Proceedings of the 4th international conference on Computer graphics and interactive techniques in Australasia and Southeast Asia - GRAPHITE '06  
Each segment contains several thousand tetrahedra and covers either a part of the original tetrahedral mesh or a simplified version of the mesh.  ...  The segments are stored in a simple, but efficient compressed format which not only saves disc space but also allows for an easy calculation of the incidency information between segments at decompression  ...  The authors would like to thank Neely and Batina from NASA for the Fighter model, Alex Smith and Bridget Wilson from the University of New Mexico and Jason Shepherd and Shawn Means of Sandia National Laboratories  ... 
doi:10.1145/1174429.1174507 dblp:conf/graphite/SondershausS06 fatcat:mazke2rcozhatjqrvzkvuoxkpi

Mont'e Scan

Fabio Bettio, Ruggero Pintus, Alberto Jaspe Villanueva, Emilio Merella, Fabio Marton, Enrico Gobbetti
2015 ACM Journal on Computing and Cultural Heritage  
the geometry of the object.  ...  The approach has been evaluated on a large scale acquisition campaign of the Mont'e Prama complex.  ...  The authors are grateful to Marco Minoja, Elena Romoli, and Alessandro Usai of ArcheoCAOR for supporting this project and to Daniela Rovina, Alba Canu, Luisanna Usai and all the personnel of CRCBC for  ... 
doi:10.1145/2644823 fatcat:hjdqyk72qfhb5iry2mbinr2hvu

Developments in Surface Crack Detection by the A.C. Field Technique [chapter]

D. Mirshekar-Syahkal, R. Collins, D. H. Michael
1985 Review of Progress in Quantitative Nondestructive Evaluation  
Here the current is induced into the plate by passing a current through an adjacent parallel plate or a set of parallel wires.  ...  With these asymptotes set, we turn now to the more general solution of problem for the geometry of Fig. 1 but with arbitrary values of a/b and d/b. The equation for I/!  ... 
doi:10.1007/978-1-4615-9421-5_39 fatcat:lis6qnpks5fihoyg3ii62p2sbm

A mathematical model of laser directed energy deposition for process mapping and geometry prediction of Ti-5553 single-tracks

M. Ansari, A. Martinez-Marchese, Y. Huang, E. Toyserkani
2020 Materialia  
This research first tries to analytically couple the moving laser beam, the powder stream, and the semi-infinite substrate.  ...  A clear understanding of the interaction of the laser beam, powder, and substrate and its effects on the temperature field and geometrical characteristics of the melt pool, is of tremendous importance.  ...  Acknowledgments The authors would like to acknowledge the financial support of the Natural Sciences and Engineering Research Council of Canada (NSERC), and the Ontario Research Fund -Research Excellence  ... 
doi:10.1016/j.mtla.2020.100710 fatcat:4ovkeyiz6bbnrc4tibdt75s3pu

An analytical hybrid GORT model for bidirectional reflectance over discontinuous plant canopies

Wenge Ni, Xiaowen Li, C.E. Woodcock, M.R. Caetano, A.H. Strahler
1999 IEEE Transactions on Geoscience and Remote Sensing  
The benefits of the model presented are simplicity, improved treatment of multiple scattering and a new method of estimating the component signatures.  ...  i.e., bowl shape and the hotspot.  ...  Qin also contributed to the improvement of this manuscript. Special thanks to G. Meister for his critical reading on this manuscript.  ... 
doi:10.1109/36.752217 fatcat:66c6axjabzbypivrruruvayicy

Context-Based Coding of Adaptive Multiresolution Meshes

Christoph von Tycowicz, Felix Kälberer, Konrad Polthier
2011 Computer graphics forum (Print)  
Using improved context modeling we enhanced the zerotree compression, cutting the overall geometry data rate by 7% below those of the successful Progressive Geometry Compression.  ...  We use the rules that correspond to the adaptive refinement scheme and store bits only where some freedom of choice is left, leading to compact codes that are free of redundancy.  ...  Models are courtesy of Stanford University, Caltech, Aim@Shape, Polygon Technologies and the Visible Human Project.  ... 
doi:10.1111/j.1467-8659.2011.01972.x fatcat:sb6nalzh4ncozjnqiyxsu23zj4

Photorealistic rendering of mixed reality scenes

Joel Kronander, Francesco Banterle, Andrew Gardner, Ehsan Miandji, Jonas Unger
2015 Computer graphics forum (Print)  
This report gives an overview of the state-of-the-art in this field, and presents a categorization and comparison of current methods.  ...  Our in-depth survey provides a tool for understanding the advantages and disadvantages of each method, and gives an overview of which technique is best suited to a specific problem.  ...  We thank the authors of the original publications for providing images and data: Paul Debevec, Kevin Karsch, Erik Reinhard, Jean-François Lalonde, Lukas Gruber, and Guanyu Xing.  ... 
doi:10.1111/cgf.12591 fatcat:7jbq4xjkkjhbvd6n4a5af43jdi

Analysis and testing of rod-like penetrators in the 4–5 km/s velocity regime

John Vetrovec, Rees Padfield, Daniel Schwab, Peter Nebolsine, Richard Hayami, Mark Zwiener, John Huntington, Steven L. Hancock
2001 International Journal of Impact Engineering  
This work describes the analysis and ballistic range testing to evaluate the performance of rod-like Kill Enhancement Device (KED) penetrators on of multi-layered targets covering large range of densities  ...  Tests showed that (1) highdensity material can be penetrated at oblique angles of incidence without projectile fragmentation and (2) high explosive within the target can be initiated.  ...  Its success was made possible by a close collaboration of many individuals and several organizations. In particular, foundations for this work were  ... 
doi:10.1016/s0734-743x(01)00133-6 fatcat:5aou7znjwfcvbcmkxaowpb2wju

Imperfect shadow maps for efficient computation of indirect illumination

T. Ritschel, T. Grosch, M. H. Kim, H.-P. Seidel, C. Dachsbacher, J. Kautz
2008 ACM Transactions on Graphics  
The scene is illuminated with a small spot light (upper right); all other illumination and shadowing is indirect (one bounce).  ...  Abstract We present a method for interactive computation of indirect illumination in large and fully dynamic scenes based on approximate visibility queries.  ...  Part of the research was funded by EPSRC grant EP/E047343/1.  ... 
doi:10.1145/1409060.1409082 fatcat:s566ltbpebg4xncnv56a3xntmm

A spatial approach to morphological feature extraction from irregularly sampled scalar fields

Leila De Floriani, Federico Iuricich, Riccardo Fellegara, Kenneth Weiss
2012 Proceedings of the Third ACM SIGSPATIAL International Workshop on GeoStreaming - IWGS '12  
We demonstrate the effectiveness and scalability of our approach over irregular simplicial meshes in 2D and in 3D with a set of streaming algorithms which extract topological features of the associated  ...  ] , which uses a spatial index over the embedding space of the complex to locally reconstruct the connectivity among its cells.  ...  The output is a simplicial i-complex covering an i-cell of the descending/ascending Morse complex (i.e., an i-manifold).  ... 
doi:10.1145/2442968.2442974 dblp:conf/gis/FlorianiIFW12 fatcat:sab7hyu5tfde5l6aqjh4vdf3f4

Imperfect shadow maps for efficient computation of indirect illumination

T. Ritschel, T. Grosch, M. H. Kim, H.-P. Seidel, C. Dachsbacher, J. Kautz
2008 ACM SIGGRAPH Asia 2008 papers on - SIGGRAPH Asia '08  
The scene is illuminated with a small spot light (upper right); all other illumination and shadowing is indirect (one bounce).  ...  Abstract We present a method for interactive computation of indirect illumination in large and fully dynamic scenes based on approximate visibility queries.  ...  Part of the research was funded by EPSRC grant EP/E047343/1.  ... 
doi:10.1145/1457515.1409082 fatcat:55bxagqxfndehcmxs2m4apzr2u

Direct measurements of ocean surface velocity from space: Interpretation and validation

Bertrand Chapron
2005 Journal of Geophysical Research  
the radar projected on the sea surface, respectively, and γ as a coefficient function of the wind speed, wave development, and radar geometry.  ...  It is found that for an incidence angle of 23°, γ ≈ 0.3 for moderate winds and fully developed seas.  ...  We would like to acknowlege the technical support provided by the European Space  ... 
doi:10.1029/2004jc002809 fatcat:jvj4cdckkje75p7gmyiyujl3oy

Quad-Mesh Generation and Processing: A Survey

David Bommes, Bruno Lévy, Nico Pietroni, Enrico Puppo, Claudio Silva, Marco Tarini, Denis Zorin
2013 Computer graphics forum (Print)  
Triangle meshes have been nearly ubiquitous in computer graphics, and a large body of data structures and geometry processing algorithms based on them has been developed in the literature.  ...  At the same time, quadrilateral meshes, especially semi-regular ones, have advantages for many applications, and significant progress was made in quadrilateral mesh generation and processing during the  ...  Acknowledgments Silva has been supported by grants from the National Science Foundation, the Department of Energy, and Exxon-Mobil.  ... 
doi:10.1111/cgf.12014 fatcat:324kimsmqvgm3ea7obxr7cq5ue

Solar SW radiative transfer in bubbled ice: spectral considerations, subsurface enhancement, and inclusions

Andrew R. D. Smedley, Geoffrey W. Evatt, Amy Mallinson, Eleanor Harvey
2018 The Cryosphere Discussions  
For macroscopic absorbing inclusions we observe geometry- and size- dependent self-shadowing that reduces the fractional irradiance incident on the inclusion's surface.  ...  A subsurface peak is also observed in the available radiative flux at depths of ~<span class="thinspace"></span>1<span class="thinspace"></span>cm, and consequently the attenuation is more complex than  ...  Acknowledgements The authors would like to acknowledge the follow sources of support that facilitated this study and preparation of the  ... 
doi:10.5194/tc-2018-79 fatcat:txsy5by57fgm3dmzldt7z6bl4e
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