Frequency domain normal map filtering
ACM SIGGRAPH 2007 papers
Joint Segmentation of Thalamic Nuclei from a Population of Diffusion Tensor MR Images
MICCAI '08 Proceedings of the 11th international conference on Medical Image Computing and Computer-Assisted Intervention - Part I
Discovering Structure in the Space of Activation Profiles in fMRI
MICCAI '08 Proceedings of the 11th international conference on Medical Image Computing and Computer-Assisted Intervention - Part I
View-Invariant Pose Recognition Using Multilinear Analysis and the Universum
ISVC '08 Proceedings of the 4th International Symposium on Advances in Visual Computing, Part II
Information theoretic measures for clusterings comparison: is a correction for chance necessary?
ICML '09 Proceedings of the 26th Annual International Conference on Machine Learning
Recognizing body poses using multilinear analysis and semi-supervised learning
Pattern Recognition Letters
Exploratory fMRI Analysis without Spatial Normalization
IPMI '09 Proceedings of the 21st International Conference on Information Processing in Medical Imaging
Spatial fading correlation model using mixtures of Von Mises Fisher distributions
IEEE Transactions on Wireless Communications
A large-scale active learning system for topical categorization on the web
Proceedings of the 19th international conference on World wide web
IEEE/ACM Transactions on Computational Biology and Bioinformatics (TCBB)
Multi-prototype vector-space models of word meaning
HLT '10 Human Language Technologies: The 2010 Annual Conference of the North American Chapter of the Association for Computational Linguistics
A directional laplacian density for underdetermined audio source separation
ICANN'10 Proceedings of the 20th international conference on Artificial neural networks: Part I
Lighting aware preprocessing for face recognition across varying illumination
ECCV'10 Proceedings of the 11th European conference on Computer vision: Part II
The Journal of Machine Learning Research
Mixed-membership naive Bayes models
Data Mining and Knowledge Discovery
Spherical statistics and spatial correlation for multielement antenna systems
EURASIP Journal on Wireless Communications and Networking
Stochastic modeling of a glass fiber reinforced polymer
ISMM'11 Proceedings of the 10th international conference on Mathematical morphology and its applications to image and signal processing
MLMI'11 Proceedings of the Second international conference on Machine learning in medical imaging
Efficient semi-supervised learning on locally informative multiple graphs
Pattern Recognition
Proceedings of the 20th ACM international conference on Information and knowledge management
Loose-limbed People: Estimating 3D Human Pose and Motion Using Non-parametric Belief Propagation
International Journal of Computer Vision
Nonparametric Bayes classification and hypothesis testing on manifolds
Journal of Multivariate Analysis
A plug-in rule for bandwidth selection in circular density estimation
Computational Statistics & Data Analysis
Fast estimation and rendering of indirect highlights
EGSR'10 Proceedings of the 21st Eurographics conference on Rendering
The multivariate Watson distribution: Maximum-likelihood estimation and other aspects
Journal of Multivariate Analysis
Distribution of functionals of a Ferguson-Dirichlet process over an n-dimensional ball
Journal of Multivariate Analysis
Adaptive multi-modal particle filtering for probabilistic white matter tractography
IPMI'13 Proceedings of the 23rd international conference on Information Processing in Medical Imaging
Computational representation of white matter fiber orientations
Journal of Biomedical Imaging
An efficient and scalable family of algorithms for combining clusterings
Engineering Applications of Artificial Intelligence
Proceedings of the Fourth Symposium on Information and Communication Technology
Document clustering using dirichlet process mixture model of von Mises-Fisher distributions
Proceedings of the Fourth Symposium on Information and Communication Technology
Detecting non-gaussian geographical topics in tagged photo collections
Proceedings of the 7th ACM international conference on Web search and data mining
Model-based clustering of probability density functions
Advances in Data Analysis and Classification
Hidden Markov Model on a unit hypersphere space for gesture trajectory recognition
Pattern Recognition Letters
Rule-based trajectory segmentation for modeling hand motion trajectory
Pattern Recognition
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Several large scale data mining applications, such as text categorization and gene expression analysis, involve high-dimensional data that is also inherently directional in nature. Often such data is L2 normalized so that it lies on the surface of a unit hypersphere. Popular models such as (mixtures of) multi-variate Gaussians are inadequate for characterizing such data. This paper proposes a generative mixture-model approach to clustering directional data based on the von Mises-Fisher (vMF) distribution, which arises naturally for data distributed on the unit hypersphere. In particular, we derive and analyze two variants of the Expectation Maximization (EM) framework for estimating the mean and concentration parameters of this mixture. Numerical estimation of the concentration parameters is non-trivial in high dimensions since it involves functional inversion of ratios of Bessel functions. We also formulate two clustering algorithms corresponding to the variants of EM that we derive. Our approach provides a theoretical basis for the use of cosine similarity that has been widely employed by the information retrieval community, and obtains the spherical kmeans algorithm (kmeans with cosine similarity) as a special case of both variants. Empirical results on clustering of high-dimensional text and gene-expression data based on a mixture of vMF distributions show that the ability to estimate the concentration parameter for each vMF component, which is not present in existing approaches, yields superior results, especially for difficult clustering tasks in high-dimensional spaces.