Search results for "Conditional random field"

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Arabic Named Entity Recognition: A Feature-Driven Study

2009

The named entity recognition task aims at identifying and classifying named entities within an open-domain text. This task has been garnering significant attention recently as it has been shown to help improve the performance of many natural language processing applications. In this paper, we investigate the impact of using different sets of features in three discriminative machine learning frameworks, namely, support vector machines, maximum entropy and conditional random fields for the task of named entity recognition. Our language of interest is Arabic. We explore lexical, contextual and morphological features and nine data-sets of different genres and annotations. We measure the impact …

Conditional random fieldAcoustics and UltrasonicsComputer sciencebusiness.industryPrinciple of maximum entropycomputer.software_genreMachine learningLinear discriminant analysisCable televisionSupport vector machineDiscriminative modelNamed-entity recognitionEntropy (information theory)Artificial intelligenceElectrical and Electronic EngineeringbusinesscomputerNatural language processingIEEE Transactions on Audio, Speech, and Language Processing
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Gesture Modeling by Hanklet-Based Hidden Markov Model

2015

In this paper we propose a novel approach for gesture modeling. We aim at decomposing a gesture into sub-trajectories that are the output of a sequence of atomic linear time invariant (LTI) systems, and we use a Hidden Markov Model to model the transitions from the LTI system to another. For this purpose, we represent the human body motion in a temporal window as a set of body joint trajectories that we assume are the output of an LTI system. We describe the set of trajectories in a temporal window by the corresponding Hankel matrix (Hanklet), which embeds the observability matrix of the LTI system that produced it. We train a set of HMMs (one for each gesture class) with a discriminative a…

Conditional random fieldKinectbusiness.industryComputer scienceMaximum-entropy Markov modelAction ClassificationHankel matrixMarkov modelHidden Markov ModelLTI system theoryGestureAction RecognitionGesture recognitionObservabilityArtificial intelligencebusinessHidden Markov modelAlgorithmHankel matrixSkeleton
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