Machine learning

For the journal, see Machine Learning (journal).

As a broad subfield of artificial intelligence, machine learning is concerned with the design and development of algorithms and techniques that allow computers to "learn". At a general level, there are two types of learning: inductive, and deductive. Inductive machine learning methods extract rules and patterns out of massive data sets.

The major focus of machine learning research is to extract information from data automatically, by computational and statistical methods. Hence, machine learning is closely related not only to data mining and statistics, but also theoretical computer science.

Applications

Machine learning has a wide spectrum of applications including natural language processing, syntactic pattern recognition, search engines, medical diagnosis, bioinformatics and cheminformatics, detecting credit card fraud, stock market analysis, classifying DNA sequences, speech and handwriting recognition, object recognition in computer vision, game playing and robot locomotion.

Human interaction

Some machine learning systems attempt to eliminate the need for human intuition in the analysis of the data, while others adopt a collaborative approach between human and machine. Human intuition cannot be entirely eliminated since the designer of the system must specify how the data is to be represented and what mechanisms will be used to search for a characterization of the data. Machine learning can be viewed as an attempt to automate parts of the scientific method.

Some statistical machine learning researchers create methods within the framework of Bayesian statistics.

Algorithm types

Machine learning algorithms are organized into a taxonomy, based on the desired outcome of the algorithm. Common algorithm types include:

• Supervised learning — in which the algorithm generates a function that maps inputs to desired outputs. One standard formulation of the supervised learning task is the classification problem: the learner is required to learn (to approximate) the behavior of a function which maps a vector $[X_{1},X_{2},\ldots X_{N}]\,$ into one of several classes by looking at several input-output examples of the function.
• Unsupervised learning — An agent which models a set of inputs: labeled examples are not available.
• Semi-supervised learning — which combines both labeled and unlabeled examples to generate an appropriate function or classifier.
• Reinforcement learning — in which the algorithm learns a policy of how to act given an observation of the world. Every action has some impact in the environment, and the environment provides feedback that guides the learning algorithm.
• Transduction — similar to supervised learning, but does not explicitly construct a function: instead, tries to predict new outputs based on training inputs, training outputs, and test inputs which are available while training.
• Learning to learn — in which the algorithm learns its own inductive bias based on previous experience.

The computational analysis of machine learning algorithms and their performance is a branch of theoretical computer science known as computational learning theory.

Machine learning topics

This list represents the topics covered on a typical machine learning course.

Prerequisites

• Bayesian theory

Modeling conditional probability density functions: regression and classification

• Artificial neural networks
• Decision trees
• Gene expression programming
• Genetic algorithms
• Genetic programming
• Inductive Logic Programming
• Gaussian process regression
• Linear discriminant analysis
• K-nearest neighbor
• Minimum message length
• Perceptron
• Quadratic classifier
• Radial basis function networks
• Support vector machines

Algorithms for estimating model parameters

• Dynamic programming
• Expectation-maximization algorithm

Modeling probability density functions through generative models

• Graphical models including Bayesian networks and Markov random fields
• Generative topographic map

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Approximate inference techniques

• Monte Carlo methods
• Variational Bayes
• Variable-order Markov models
• Variable-order Bayesian networks
• Loopy belief propagation

Optimization

• Most of methods listed above either use optimization or are instances of optimization algorithms

Meta-learning (ensemble methods)

• Boosting
• Bootstrap aggregating
• Random forest
• Weighted majority algorithm

Inductive transfer and learning to learn

• Inductive transfer
• Reinforcement learning
• Temporal difference learning
• Monte-Carlo method

See also

• Autonomous robot
• Computational intelligence
• Fuzzy logic
• Inductive logic programming
• Intelligent system
• Journal of Machine Learning Research
• Important publications in machine learning (computer science)
• List of numerical analysis software
• MLMTA Machine Learning: Models, Technologies & Applications
• Multi-label classification
• Neural Information Processing Systems (NIPS) (conference)
• Neural network software
• Pattern recognition
• Predictive analytics
• WEKA Open-source machine learning framework for pattern classification, regression, and clustering.

Bibliography

• Ethem Alpaydın (2004) Introduction to Machine Learning (Adaptive Computation and Machine Learning), MIT Press, ISBN 0262012111
• Christopher M. Bishop (2007) Pattern Recognition and Machine Learning, Springer ISBN 0-387-31073-8.
• Ryszard S. Michalski, Jaime G. Carbonell, Tom M. Mitchell (1983), Machine Learning: An Artificial Intelligence Approach, Tioga Publishing Company, ISBN 0-935382-05-4.
• Ryszard S. Michalski, Jaime G. Carbonell, Tom M. Mitchell (1986), Machine Learning: An Artificial Intelligence Approach, Volume II, Morgan Kaufmann, ISBN 0-934613-00-1.
• Yves Kodratoff, Ryszard S. Michalski (1990), Machine Learning: An Artificial Intelligence Approach, Volume III, Morgan Kaufmann, ISBN 1-55860-119-8.
• Ryszard S. Michalski, George Tecuci (1994), Machine Learning: A Multistrategy Approach, Volume IV, Morgan Kaufmann, ISBN 1-55860-251-8.
• Bhagat, P. M. (2005). Pattern Recognition in Industry, Elsevier. ISBN 0-08-044538-1.
• Bishop, C. M. (1995). Neural Networks for Pattern Recognition, Oxford University Press. ISBN 0-19-853864-2.
• Richard O. Duda, Peter E. Hart, David G. Stork (2001) Pattern classification (2nd edition), Wiley, New York, ISBN 0-471-05669-3.
• Huang T.-M., Kecman V., Kopriva I. (2006), Kernel Based Algorithms for Mining Huge Data Sets, Supervised, Semi-supervised, and Unsupervised Learning, Springer-Verlag, Berlin, Heidelberg, 260 pp. 96 illus., Hardcover, ISBN 3-540-31681-7.
• KECMAN Vojislav (2001), LEARNING AND SOFT COMPUTING, Support Vector Machines, Neural Networks and Fuzzy Logic Models, The MIT Press, Cambridge, MA, 608 pp., 268 illus., ISBN 0-262-11255-8.
• MacKay, D. J. C. (2003). Information Theory, Inference, and Learning Algorithms, Cambridge University Press. ISBN 0-521-64298-1.
• Mitchell, T. (1997). Machine Learning, McGraw Hill. ISBN 0-07-042807-7.
• Ian H. Witten and Eibe Frank "Data Mining: Practical machine learning tools and techniques" Morgan Kaufmann ISBN 0-12-088407-0.
• Sholom Weiss and Casimir Kulikowski (1991). Computer Systems That Learn, Morgan Kaufmann. ISBN 1-55860-065-5.
• Mierswa, Ingo and Wurst, Michael and Klinkenberg, Ralf and Scholz, Martin and Euler, Timm: YALE: Rapid Prototyping for Complex Data Mining Tasks, in Proceedings of the 12th ACM SIGKDD International Conference on Knowledge Discovery and Data Mining (KDD-06), 2006.
• Trevor Hastie, Robert Tibshirani and Jerome Friedman (2001). The Elements of Statistical Learning, Springer. ISBN 0387952845.
• Vladimir Vapnik (1998). Statistical Learning Theory. Wiley-Interscience, ISBN 0471030031.

External links

• International Machine Learning Society
• Machine Learning Department at CMU
• Machine Learning Group University of Edinburgh
• Index of Machine Learning Courses
• Kmining List of machine learning, data mining and KDD scientific conferences
• The Encyclopedia of Computational Intelligence
• Machine Learning Open Source Software
• Machine Learning Tutorials