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A Tutorial On Hidden Markov Models
 Signal Processing and Artificial Neural Networks Laboratory Department of Electrical Engineering Indian Institute of Technology — Bombay Powai, Bombay 400 076, India
, 1996
"... In this tutorial we present an overview of (i) what are HMMs, (ii) what are the different problems associated with HMMs, (iii) the Viterbi algorithm for determining the optimal state sequence, (iv) algorithms associated with training HMMs, and (v) distance between HMMs. 1 Introduction [1] Suppo ..."
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In this tutorial we present an overview of (i) what are HMMs, (ii) what are the different problems associated with HMMs, (iii) the Viterbi algorithm for determining the optimal state sequence, (iv) algorithms associated with training HMMs, and (v) distance between HMMs. 1 Introduction [1] Suppose a person has say three coins and is sitting inside a room tossing them in some sequence this room is closed and what you are shown (on a display outside the room) is only the outcomes of his tossing TTHTHHTT. . . this will be called the observation sequence . You do not know the sequence in which he is tossing the different coins, nor do you know the bias of the various coins. To appreciate how much the outcome depends on the individual biasing and the order of tossing the coins, suppose you are given that the third coin is highly biased to produce heads and all coins are tossed with equal probability. Then, we naturally expect there to be far greater number of heads than tails in the o...
Convergence analysis and optimal scheduling for multiple concatenated codes
 IEEE Transactions on Information Theory
, 2005
"... Abstract—An interesting practical consideration for decoding of serial or parallel concatenated codes with more than two components is the determination of the lowest complexity component decoder schedule which results in convergence. This correspondence presents an algorithm that finds such an opti ..."
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Abstract—An interesting practical consideration for decoding of serial or parallel concatenated codes with more than two components is the determination of the lowest complexity component decoder schedule which results in convergence. This correspondence presents an algorithm that finds such an optimal decoder schedule. A technique is also given for combining and projecting a series of threedimensional extrinsic information transfer (EXIT) functions onto a single twodimensional EXIT chart. This is a useful technique for visualizing the convergence threshold for multiple concatenated codes and provides a design tool for concatenated codes with more than two components. Index Terms—EXIT chart, iterative decoding, multiple concatenated codes, optimal scheduling. I.
Autonomous terrain mapping and classification using hidden markov models
 In Proc. IEEE International Conference on Robotics and Automation (ICRA
, 2005
"... Abstract — This paper presents a new approach for terrain mapping and classification using mobile robots with 2D laser range finders. Our algorithm generates 3D terrain maps and classifies navigable and nonnavigable regions on those maps using Hidden Markov models. The maps generated by our approac ..."
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Cited by 19 (2 self)
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Abstract — This paper presents a new approach for terrain mapping and classification using mobile robots with 2D laser range finders. Our algorithm generates 3D terrain maps and classifies navigable and nonnavigable regions on those maps using Hidden Markov models. The maps generated by our approach can be used for path planning, navigation, local obstacle avoidance, detection of changes in the terrain, and object recognition. We propose a map segmentation algorithm based on Markov Random Fields, which removes small errors in the classification. In order to validate our algorithms, we present experimental results using two robotic platforms. I.
Incorporating Syntactic Constraints in Recognizing Handwritten Sentences
 IN PROCEEDINGS OF THE INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE (IJCAI93
, 1993
"... The output of handwritten word recognizers (HWR) tends to be very noisy due to various factors. In order to compensate for this behaviour, several choices of the HWR must be initially considered. In the case of handwritten sentence/phrase recognition, linguistic constraints may be applied in order t ..."
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Cited by 16 (3 self)
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The output of handwritten word recognizers (HWR) tends to be very noisy due to various factors. In order to compensate for this behaviour, several choices of the HWR must be initially considered. In the case of handwritten sentence/phrase recognition, linguistic constraints may be applied in order to improve the results of the HWR. This paper discusses two statistical methods of applying syntactic constraints to the output of an HWR on input consisting of sentences/phrases. Both methods are based on syntactic categories (tags) associated with words. The first is a purely statistical method, the second is a hybrid method which combines higherlevel syntactic information (hypertags) with statistical information regarding transitions between hypertags.
Joint and LPA*: combination of approximation and search
 In AAAI
, 1986
"... This paper describes two new algorithms, Joint and LPA*, which can be used to solve difficult combinatorial problems heuristically. The algorithms find reasonably short solution paths and are very fast. The algorithms work in polynomial time in the length of the solution. The algorithms have been be ..."
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Cited by 16 (0 self)
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This paper describes two new algorithms, Joint and LPA*, which can be used to solve difficult combinatorial problems heuristically. The algorithms find reasonably short solution paths and are very fast. The algorithms work in polynomial time in the length of the solution. The algorithms have been benchmarked on the 15puzzle, whose generalization has recently been shown to be NP hard, and outperform other known methods within this context. I.
Multiple description trelliscoded quantization
 IEEE Trans. Commun
, 1999
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permission. The MADlib Analytics Library or MAD Skills, the SQL
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Modelbased monitoring and diagnosis of systems with softwareextended behavior
 In Proc. 20th National Conference on Artificial Intelligence
, 2005
"... Modelbased diagnosis has largely operated on hardware systems. However, in most complex systems today, hardware is augmented with software functions that influence the system’s behavior. In this paper, hardware models are extended to include the behavior of associated embedded software, resulting i ..."
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Modelbased diagnosis has largely operated on hardware systems. However, in most complex systems today, hardware is augmented with software functions that influence the system’s behavior. In this paper, hardware models are extended to include the behavior of associated embedded software, resulting in more comprehensive diagnoses. Prior work introduced probabilistic, hierarchical, constraintbased automata (PHCA) to allow the uniform and compact encoding of both hardware and software behavior. This paper focuses on PHCAbased monitoring and diagnosis to ensure the robustness of complex systems. We introduce a novel approach that frames diagnosis over a finite time horizon as a soft constraint optimization problem (COP), allowing us to leverage an extensive body of efficient solution methods for COPs. The solutions to the COP correspond to the most likely evolutions of the complex system. We demonstrate our approach on a visionbased rover navigation system, and models of the SPHERES and Earth Observing One spacecraft.
Autobib: Automatic extraction of bibliographic information on the web
 Proceedings of the 8th International Database Engineering and Applications Symposium (IDEAS’04
, 2004
"... The Web has greatly facilitated access to information. However, information presented in HTML is mainly intended to be browsed by humans, and the problem of automatically extracting such information remains an important and challenging task. In this work, we focus on building a system called AUTOBIB ..."
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The Web has greatly facilitated access to information. However, information presented in HTML is mainly intended to be browsed by humans, and the problem of automatically extracting such information remains an important and challenging task. In this work, we focus on building a system called AUTOBIB to automate extraction of bibliographic information on the Web. We use a combination of bootstrapping, statistical, and heuristic methods to achieve a high degree of automation. To set up extraction from a new site, we only need to provide a few lines of code specifying how to download pages containing bibliographic information. We do not need to be concerned with each site’s presentation format, and the system can cope with changes in the presentation format without human intervention. AUTOBIB bootstraps itself with a small seed database of structured bibliographic records. For each bibliographic Web site, we identify segments within its pages that represent bibliographic records, using stateoftheart recordboundary discovery techniques. Next, we find matches for some of these “raw records ” in the seed database using a set of heuristics. These matches serve as a training set for a parser based on the Hidden Markov Model (HMM), which is then used to parse the rest of the raw records into structured records. We have found an effective HMM structure with special states that correspond to delimiters and HTML tags in raw records. Experiments demonstrate that for our application, this HMM structure achieves high success rates without the complexity of previously proposed structures. 1.