Search results for "Tensor"

Hits ?▲	Authors	Title	Venue	Year	Link	Author keywords
34	Isabelle Corouge, Sylvain Gouttard, Guido Gerig	A Statistical Shape Model of Individual Fiber Tracts Extracted from Diffusion Tensor MRI.	MICCAI (2)	2004	DBLP DOI BibTeX RDF	statistical shape modelling, Diffusion Tensor Imaging
34	Song Zhang 0004, Çagatay Demiralp, David H. Laidlaw	Visualizing Diffusion Tensor MR Images Using Streamtubes and Streamsurfaces.	IEEE Trans. Vis. Comput. Graph.	2003	DBLP DOI BibTeX RDF	streamsurface, streamtube, scientific visualization, volume visualization, immersive virtual reality, Diffusion tensor imaging, DTI, DT-MRI, hyperstreamline
34	Paul E. Buis, Wayne R. Dyksen	Efficient Vector and Parallel Manipulation of Tensor Products.	ACM Trans. Math. Softw.	1996	DBLP DOI BibTeX RDF	parallel, vector, LAPACK, tensor product
34	Gabriel Taubin	Estimating the Tensor of Curvature of a Surface from a Polyhedral Approximation.	ICCV	1995	DBLP DOI BibTeX RDF	tensor of curvature, polyhedral approximation, principal curvature estimation, iso-surface construction algorithms, symmetric matrices, integral formulas, computer vision, computer vision, computational geometry, surface, eigenvalues, medical applications, tensors, eigenvectors, eigenvalues and eigenfunctions, polyhedral surface, matrix representation
34	Michael S. Floater	A weak condition for the convexity of tensor-product Bézier and B-spline surfaces.	Adv. Comput. Math.	1994	DBLP DOI BibTeX RDF	Bézier surface, Convexity, tensor-product, B-spline surface
34	Gemma Piella	Image Fusion for Enhanced Visualization: A Variational Approach.	Int. J. Comput. Vis.	2009	DBLP DOI BibTeX RDF	Perceptual contrast enhancement, Geometry-based fusion, Image fusion, Structure tensor
34	Joon-Kyung Seong, Won-Ki Jeong, Elaine Cohen	Curvature-based anisotropic geodesic distance computation for parametric and implicit surfaces.	Vis. Comput.	2009	DBLP DOI BibTeX RDF	Parametric and implicit surface, Normal curvature, H-J equation, Tensor, Geodesic, Anisotropy
34	René Vidal, Richard I. Hartley	Three-View Multibody Structure from Motion.	IEEE Trans. Pattern Anal. Mach. Intell.	2008	DBLP DOI BibTeX RDF	multibody structure from motion, 3-D motion segmentation, multibody trilinear constraint, multibody trifocal tensor and Generalized PCA (GPCA)
34	Ying Guo	Group Independent Component Analysis of Multi-subject fMRI Data: Connections and Distinctions between Two Methods.	BMEI (2)	2008	DBLP DOI BibTeX RDF	tensor PICA, Group comparison, Multisubject analysis, Independent component analysis, fMRI, GIFT
34	Cheng Qin, Ning Kang 0008, Ning Cao 0006	Performance evaluation of anisotropic diffusion simulation based tractography on phantom images.	ACM Southeast Regional Conference	2007	DBLP DOI BibTeX RDF	diffusion simulation based tractography (DST), diffusion tensor magnetic resonance imaging (DT-MRI), phantom images for simulating tractography errors (PISTE)
34	Mircea Nicolescu, Gérard G. Medioni	Layered 4D Representation and Voting for Grouping from Motion.	IEEE Trans. Pattern Anal. Mach. Intell.	2003	DBLP DOI BibTeX RDF	Motion analysis, perceptual grouping, tensor voting
34	Mi-Suen Lee, Gérard G. Medioni, Philippos Mordohai	Inference of Segmented Overapping Surfaces from Binocular Stereo.	IEEE Trans. Pattern Anal. Mach. Intell.	2002	DBLP DOI BibTeX RDF	surface inference, perceptual grouping, tensor voting, Binocular stereo
34	Michael Felsberg, Gerald Sommer	Image Features Based on a New Approach to 2D Rotation Invariant Quadrature Filters.	ECCV (1)	2002	DBLP DOI BibTeX RDF	quadrature filters, analytic signal, point-of-interest operator, image features, orientation estimation, structure tensor
34	Bill Triggs	Differential Matching Constraints.	ICCV	1999	DBLP DOI BibTeX RDF	Matching Tensors, Tensor Tracking, Difference Expansion, Image Sequences, Matching Constraints
34	Anders Heyden	Reconstruction from Image Sequences by Means of Relative Depths.	ICCV	1995	DBLP DOI BibTeX RDF	relative depths, reduced fundamental matrix, reduced fundamental tensor, camera matrices, image sequences, image sequences, image reconstruction, image reconstruction, matrix algebra, tensors, canonical form, theoretical framework
33	Richard I. Hartley, Frederik Schaffalitzky	Reconstruction from Projections Using Grassmann Tensors.	Int. J. Comput. Vis.	2009	DBLP DOI BibTeX RDF	Grassman tensor, Multiview tensor, Exterior algebra, Projective reconstruction
33	Yaniv Gur, Ofer Pasternak, Nir A. Sochen	Fast GL(n)-Invariant Framework for Tensors Regularization.	Int. J. Comput. Vis.	2009	DBLP DOI BibTeX RDF	Beltrami framework, Tensor-valued image, PDEs, Differential geometry, Diffusion tensor imaging
33	Thomas Schultz 0001, Holger Theisel, Hans-Peter Seidel	Topological Visualization of Brain Diffusion MRI Data.	IEEE Trans. Vis. Comput. Graph.	2007	DBLP DOI BibTeX RDF	probabilistic fiber tracking, uncertainty visualization, Diffusion tensor, tensor topology
33	Burkhard Wünsche, Richard Lobb	The 3D visualization of brain anatomy from diffusion-weighted magnetic resonance imaging data.	GRAPHITE	2004	DBLP DOI BibTeX RDF	brain anatomy, nerve fiber tracking, diffusion tensor imaging, biomedical visualization, tensor field visualization
29	Ullrich Köthe, Michael Felsberg	Riesz-Transforms Versus Derivatives: On the Relationship Between the Boundary Tensor and the Energy Tensor.	Scale-Space	2005	DBLP DOI BibTeX RDF
28	Michael Gnewuch, Henryk Wozniakowski	Generalized Tractability for Multivariate Problems Part II: Linear Tensor Product Problems, Linear Information, and Unrestricted Tractability.	Found. Comput. Math.	2009	DBLP DOI BibTeX RDF	Mathematics Subject Classification (2000) 65D99
28	Wei Chen 0001, Zhicheng Yan, Song Zhang 0004, John Allen Crow, David S. Ebert, Ronald M. McLaughlin, Katie B. Mullins, Robert Cooper, Zi'ang Ding, Jun Liao	Volume Illustration of Muscle from Diffusion Tensor Images.	IEEE Trans. Vis. Comput. Graph.	2009	DBLP DOI BibTeX RDF
28	Stefanos Zafeiriou	Discriminant Nonnegative Tensor Factorization Algorithms.	IEEE Trans. Neural Networks	2009	DBLP DOI BibTeX RDF
28	Stefanie Jegelka, Suvrit Sra, Arindam Banerjee 0001	Approximation Algorithms for Tensor Clustering.	ALT	2009	DBLP DOI BibTeX RDF
28	Pew-Thian Yap, Guorong Wu 0001, Hongtu Zhu, Weili Lin, Dinggang Shen	Fast Tensor Image Morphing for Elastic Registration.	MICCAI (1)	2009	DBLP DOI BibTeX RDF
28	Aram W. Harrow, Richard Andrew Low	Efficient Quantum Tensor Product Expanders and k-Designs.	APPROX-RANDOM	2009	DBLP DOI BibTeX RDF
28	Cheng Guan Koay, Uri Nevo, Lin-Ching Chang, Carlo Pierpaoli, Peter J. Basser	The Elliptical Cone of Uncertainty and Its Normalized Measures in Diffusion Tensor Imaging.	IEEE Trans. Medical Imaging	2008	DBLP DOI BibTeX RDF
28	Dacheng Tao, Mingli Song, Xuelong Li 0001, Jialie Shen 0001, Jimeng Sun 0001, Xindong Wu 0001, Christos Faloutsos, Stephen J. Maybank	Bayesian Tensor Approach for 3-D Face Modeling.	IEEE Trans. Circuits Syst. Video Technol.	2008	DBLP DOI BibTeX RDF
28	Haiping Lu, Konstantinos N. Plataniotis, Anastasios N. Venetsanopoulos	MPCA: Multilinear Principal Component Analysis of Tensor Objects.	IEEE Trans. Neural Networks	2008	DBLP DOI BibTeX RDF
28	Carlos Alexandre R. Fernandes, Gérard Favier, João Cesar M. Mota	Tensor based receivers for nonlinear Radio Over Fiber uplinks in multiuser CDMA systems.	PIMRC	2008	DBLP DOI BibTeX RDF
28	Tamara G. Kolda, Jimeng Sun 0001	Scalable Tensor Decompositions for Multi-aspect Data Mining.	ICDM	2008	DBLP DOI BibTeX RDF
28	Philip A. Cook, Hui Zhang 0005, Suyash P. Awate, James C. Gee	Atlas-guided probabilistic diffusion-tensor fiber tractography.	ISBI	2008	DBLP DOI BibTeX RDF
28	Hesamoddin Jahanian, Azadeh Yazdan-Shahmorad, Hamid Soltanian-Zadeh	4D wavelet noise suppression of MR diffusion tensor data.	ICASSP	2008	DBLP DOI BibTeX RDF
28	Andreas Richter, Jussi Salmi, Visa Koivunen	ML estimation of covariance matrix for tensor valued signals in noise.	ICASSP	2008	DBLP DOI BibTeX RDF
28	Julien Marot, Salah Bourennane	Fast tensor signal filtering using fixed point algorithm.	ICASSP	2008	DBLP DOI BibTeX RDF
28	Liang Wang 0021, Fuchao Wu	A factorization algorithm for trifocal tensor estimation.	ICPR	2008	DBLP DOI BibTeX RDF
28	Letícia Rittner, Roberto de Alencar Lotufo	Diffusion Tensor Imaging Segmentation by Watershed Transform on Tensorial Morphological Gradient.	SIBGRAPI	2008	DBLP DOI BibTeX RDF
28	Dacheng Tao, Jimeng Sun 0001, Jialie Shen 0001, Xindong Wu 0001, Xuelong Li 0001, Stephen J. Maybank, Christos Faloutsos	Bayesian tensor analysis.	IJCNN	2008	DBLP DOI BibTeX RDF
28	Eli Ben-Sasson, Michael Viderman	Tensor Products of Weakly Smooth Codes Are Robust.	APPROX-RANDOM	2008	DBLP DOI BibTeX RDF
28	Wim Van Hecke, Alexander Leemans, Emiliano D'Agostino, Steve De Backer, Everhard Vandervliet, Paul M. Parizel, Jan Sijbers	Nonrigid Coregistration of Diffusion Tensor Images Using a Viscous Fluid Model and Mutual Information.	IEEE Trans. Medical Imaging	2007	DBLP DOI BibTeX RDF
28	Ragini Verma, Parmeshwar Khurd, Christos Davatzikos	On Analyzing Diffusion Tensor Images by Identifying Manifold Structure Using Isomaps.	IEEE Trans. Medical Imaging	2007	DBLP DOI BibTeX RDF
28	Rémy Boyer, Lieven De Lathauwer, Karim Abed-Meraim	Higher Order Tensor-Based Method for Delayed Exponential Fitting.	IEEE Trans. Signal Process.	2007	DBLP DOI BibTeX RDF
28	Qing Xu 0003, Adam W. Anderson, John C. Gore, Zhaohua Ding	Diffusion Tensor Image Smoothing Using Efficient and Effective Anisotropic Filtering.	ICCV	2007	DBLP DOI BibTeX RDF
28	Qing Wu 0006, Tian Xia, Yizhou Yu	Hierarchical Tensor Approximation of Multidimensional Images.	ICIP (4)	2007	DBLP DOI BibTeX RDF
28	Fernanda A. Andaló, Paulo A. V. Miranda, Ricardo da Silva Torres, Alexandre X. Falcão	Detecting Contour Saliences using Tensor Scale.	ICIP (6)	2007	DBLP DOI BibTeX RDF
28	Liang Wang 0001, Christopher Leckie, Xiaozhe Wang, Kotagiri Ramamohanarao, James C. Bezdek	Tensor Space Learning for Analyzing Activity Patterns from Video Sequences.	ICDM Workshops	2007	DBLP DOI BibTeX RDF
28	Qiang Zhang, Han Wang, Robert J. Plemmons, V. Paul Pauca	Spectral unmixing using nonnegative tensor factorization.	ACM Southeast Regional Conference	2007	DBLP DOI BibTeX RDF	space object identification, hyperspectral imaging
28	M. Alex O. Vasilescu, Demetri Terzopoulos	A Tensor Algebraic Approach to Image Synthesis, Analysis and Recognition.	3DIM	2007	DBLP DOI BibTeX RDF
28	Tae-Kyun Kim, Shu-Fai Wong, Roberto Cipolla	Tensor Canonical Correlation Analysis for Action Classification.	CVPR	2007	DBLP DOI BibTeX RDF
28	Yogesh Rathi, Allen R. Tannenbaum, Oleg V. Michailovich	Segmenting Images on the Tensor Manifold.	CVPR	2007	DBLP DOI BibTeX RDF
28	Nicolas Wiest-Daesslé, Sylvain Prima, Pierrick Coupé, Sean Patrick Morrissey, Christian Barillot	Non-Local Means Variants for Denoising of Diffusion-Weighted and Diffusion Tensor MRI.	MICCAI (2)	2007	DBLP DOI BibTeX RDF
28	Hui Zhang 0005, Paul A. Yushkevich, Daniel Rueckert, James C. Gee	Unbiased White Matter Atlas Construction Using Diffusion Tensor Images.	MICCAI (2)	2007	DBLP DOI BibTeX RDF
28	Gordon L. Kindlmann, Raúl San José Estépar, Marc Niethammer, Steven Haker, Carl-Fredrik Westin	Geodesic-Loxodromes for Diffusion Tensor Interpolation and Difference Measurement.	MICCAI (1)	2007	DBLP DOI BibTeX RDF
28	Rodrigo de Luis García, Carlos Alberola-López	Mixtures of Gaussians on Tensor Fields for DT-MRI Segmentation.	MICCAI (1)	2007	DBLP DOI BibTeX RDF
28	Khaled Z. Abd-Elmoniem, Matthias Stuber, Jerry L. Prince	Multi-slice Three-Dimensional Myocardial Strain Tensor Quantification Using z HARP.	IPMI	2007	DBLP DOI BibTeX RDF
28	P. Thomas Fletcher, Ran Tao 0011, Won-Ki Jeong, Ross T. Whitaker	A Volumetric Approach to Quantifying Region-to-Region White Matter Connectivity in Diffusion Tensor MRI.	IPMI	2007	DBLP DOI BibTeX RDF
28	Kannappan Palaniappan, Ilker Ersoy, Sumit Kumar Nath	Moving Object Segmentation Using the Flux Tensor for Biological Video Microscopy.	PCM	2007	DBLP DOI BibTeX RDF
28	Robert Pless	Detecting Roads in Stabilized Video with the Spatio-Temporal Structure Tensor.	GeoInformatica	2006	DBLP DOI BibTeX RDF	statistical video processing, stabilized video, aerial video
28	Fan Zhang 0025, Edwin R. Hancock	Edge Detection and Anisotropic Diffusion for Tensor-Valued Images.	ICIP	2006	DBLP DOI BibTeX RDF
28	Jian Xia, Dit-Yan Yeung, Guang Dai	Local Discriminant Embedding with Tensor Representation.	ICIP	2006	DBLP DOI BibTeX RDF
28	A. C. Murillo, José Jesús Guerrero, Carlos Sagüés	Robot and Landmark Localization using Scene Planes and the 1D Trifocal Tensor.	IROS	2006	DBLP DOI BibTeX RDF
28	Weihong Guo 0002, Qingguo Zeng, Yunmei Chen, Yijun Liu	Using multiple tensor deflection to reconstruct white matter fiber traces with branching.	ISBI	2006	DBLP DOI BibTeX RDF
28	Xinge You, Dan Zhang 0008, Qiuhui Chen, Patrick Shen-Pei Wang, Yuan Yan Tang	Face Representation By Using Non-tensor Product Wavelets.	ICPR (1)	2006	DBLP DOI BibTeX RDF
28	Yu-Wing Tai, Wai-Shun Tong, Chi-Keung Tang	Simultaneous Image Denoising and Compression by Multiscale 2D Tensor Voting.	ICPR (3)	2006	DBLP DOI BibTeX RDF
28	Lucas J. van Vliet, Frank G. A. Faas	Multi-orientation analysis by decomposing the structure tensor and clustering.	ICPR (3)	2006	DBLP DOI BibTeX RDF
28	Kui Jia, Shaogang Gong	Multi-Resolution Patch Tensor for Facial Expression Hallucination.	CVPR (1)	2006	DBLP DOI BibTeX RDF
28	Christopher R. Butson, Scott E. Cooper, Jaimie M. Henderson, Cameron C. McIntyre	Predicting the Effects of Deep Brain Stimulation with Diffusion Tensor Based Electric Field Models.	MICCAI (2)	2006	DBLP DOI BibTeX RDF
28	Fan Zhang 0025, Edwin R. Hancock	Smoothing Tensor-Valued Images Using Anisotropic Geodesic Diffusion.	SSPR/SPR	2006	DBLP DOI BibTeX RDF
28	Jiaya Jia, Chi-Keung Tang	Tensor Voting for Image Correction by Global and Local Intensity Alignment.	IEEE Trans. Pattern Anal. Mach. Intell.	2005	DBLP DOI BibTeX RDF	Image correction and recovery, replacement functions, applications, color transfer
28	Kui Jia, Shaogang Gong	Multi-Modal Tensor Face for Simultaneous Super-Resolution and Recognition.	ICCV	2005	DBLP DOI BibTeX RDF
28	Kui Jia, Shaogang Gong	Multi-modal face image super-resolutions in tensor space.	AVSS	2005	DBLP DOI BibTeX RDF
28	Hui Zhang 0005, Paul A. Yushkevich, James C. Gee	Deformable Registration of Diffusion Tensor MR Images with Explicit Orientation Optimization.	MICCAI	2005	DBLP DOI BibTeX RDF
28	Alexander Leemans, Jan Sijbers, Steve De Backer, Everhard Vandervliet, Paul M. Parizel	Affine Coregistration of Diffusion Tensor Magnetic Resonance Images Using Mutual Information.	ACIVS	2005	DBLP DOI BibTeX RDF
28	Markus van Almsick, Remco Duits, Erik Franken, Bart M. ter Haar Romeny	From Stochastic Completion Fields to Tensor Voting.	DSSCV	2005	DBLP DOI BibTeX RDF
28	John Wright 0001, Robert Pless	Analysis of Persistent Motion Patterns Using the 3D Structure Tensor.	WACV/MOTION	2005	DBLP DOI BibTeX RDF
28	Xiaoyang Gao, Swarup Kumar Sahoo, Chi-Chung Lam, J. Ramanujam, Qingda Lu, Gerald Baumgartner, P. Sadayappan	Performance modeling and optimization of parallel out-of-core tensor contractions.	PPoPP	2005	DBLP DOI BibTeX RDF	parallel algorithms, performance modeling, compiler optimization, out-of-core algorithms
28	Boguslaw Cyganek	Object Detection in Multi-channel and Multi-scale Images Based on the Structural Tensor.	CAIP	2005	DBLP DOI BibTeX RDF
28	Jia Wang, Hanqing Lu, Qingshan Liu 0001	Tensor Voting Toward Feature Space Analysis.	ICPR (3)	2004	DBLP DOI BibTeX RDF
28	Boguslaw Cyganek	Depth Recovery with an Area Based Version of the Stereo Matching Method with Scale-Space Tensor Representation of Local Neighborhoods.	International Conference on Computational Science	2004	DBLP DOI BibTeX RDF
28	Marcel Jackowski, Chiu Yen Kao, MaoLin Qiu, R. Todd Constable, Lawrence H. Staib	Estimation of Anatomical Connectivity by Anisotropic Front Propagation and Diffusion Tensor Imaging.	MICCAI (2)	2004	DBLP DOI BibTeX RDF
28	Mikaël Rousson, Christophe Lenglet, Rachid Deriche	Level Set and Region Based Surface Propagation for Diffusion Tensor MRI Segmentation.	ECCV Workshops CVAMIA and MMBIA	2004	DBLP DOI BibTeX RDF
28	Ullrich Köthe	Edge and Junction Detection with an Improved Structure Tensor.	DAGM-Symposium	2003	DBLP DOI BibTeX RDF
28	Marcos Martín-Fernández, Carlos Alberola-López, Juan Ruiz-Alzola, Carl-Fredrik Westin	Regularization of Diffusion Tensor Maps Using a Non-Gaussian Markov Random Field Approach.	MICCAI (2)	2003	DBLP DOI BibTeX RDF
28	Shen-Yi Lin, Chih-Shen Chen, Li Liu, Chua-Huang Huang	Tensor Product Formulation for Hilbert Space-Filling Curves.	ICPP	2003	DBLP DOI BibTeX RDF
28	Zhizhou Wang, Baba C. Vemuri, Yunmei Chen	Diffusion Tensor MR Image Restoration.	EMMCVPR	2003	DBLP DOI BibTeX RDF
28	Mukund Desai, David N. Kennedy, Rami Mangoubi, Jayant Shah, W. Clem Karl, N. Markis, Andrew J. Worth	Diffusion tensor model based smoothing.	ISBI	2002	DBLP DOI BibTeX RDF
28	Philippos Mordohai, Gérard G. Medioni	Perceptual Grouping for Multiple View Stereo Using Tensor Voting.	ICPR (3)	2002	DBLP DOI BibTeX RDF
28	Colin Studholme, Valerie Cardenas, Andrew Maudsley, Michael Weiner	An Intensity Consistent Approach to the Cross Sectional Analysis of Deformation Tensor Derived Maps of Brain Shape.	MICCAI (1)	2002	DBLP DOI BibTeX RDF
28	Mircea Nicolescu, Gérard G. Medioni	Perceptual Grouping from Motion Cues Using Tensor Voting in 4-D.	ECCV (3)	2002	DBLP DOI BibTeX RDF
28	Wai-Shun Tong, Chi-Keung Tang, Gérard G. Medioni	First Order Tensor Voting, and Application to 3-D Scale Analysis.	CVPR (1)	2001	DBLP DOI BibTeX RDF
28	Klaus Hahn, Sergei Prigarin, Benno Pütz	Edge Preserving Regularization and Tracking for Diffusion Tensor Imaging.	MICCAI	2001	DBLP DOI BibTeX RDF
28	Nikos Canterakis	A Minimal Set of Constraints for the Trivocal Tensor.	ECCV (1)	2000	DBLP DOI BibTeX RDF
28	Amnon Shashua, Lior Wolf	On the Structure and Properties of the Quadrifocal Tensor.	ECCV (1)	2000	DBLP DOI BibTeX RDF
28	Carolyn Pe Rosiene, Truong Q. Nguyen	Tensor-product wavelet vs. Mallat decomposition: a comparative analysis.	ISCAS (3)	1999	DBLP DOI BibTeX RDF
28	Shuicheng Yan, Huan Wang 0001, Jilin Tu, Xiaoou Tang, Thomas S. Huang	Mode-kn Factor Analysis for Image Ensembles.	IEEE Trans. Image Process.	2009	DBLP DOI BibTeX RDF
28	S. Charles Brubaker, Santosh S. Vempala	Random Tensors and Planted Cliques.	APPROX-RANDOM	2009	DBLP DOI BibTeX RDF
28	Kui Jia, Shaogang Gong	Generalized Face Super-Resolution.	IEEE Trans. Image Process.	2008	DBLP DOI BibTeX RDF
28	B. T. Thomas Yeo, Tom Vercauteren, Pierre Fillard, Xavier Pennec, Polina Golland, Nicholas Ayache, Olivier Clatz	DTI registration with exact finite-strain differential.	ISBI	2008	DBLP DOI BibTeX RDF
28	Pierre Fillard, Xavier Pennec, Vincent Arsigny, Nicholas Ayache	Clinical DT-MRI Estimation, Smoothing, and Fiber Tracking With Log-Euclidean Metrics.	IEEE Trans. Medical Imaging	2007	DBLP DOI BibTeX RDF
28	Robert C. Kirby, Anders Logg	Efficient compilation of a class of variational forms.	ACM Trans. Math. Softw.	2007	DBLP DOI BibTeX RDF	loop hoisting, monomials, variational form, compiler, automation, finite element, granularity, BLAS