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WEKA : A Practical Machine Learning Tool. Contents. 1.Introduction to Weka 2.Explorer 3.Other three main tools 4.Conclusions 5.Reference. Introduction – What is Weka?. Usage : The algorithms can either be applied: (1) directly to a dataset (without writing any codes);
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Contents • 1.Introduction to Weka • 2.Explorer • 3.Other three main tools • 4.Conclusions • 5.Reference
Introduction – What is Weka? • Usage: The algorithms can either be applied: (1) directly to a dataset (without writing any codes); (2) called from your own Java code. • In nature: A flightless bird with an inquisitive nature found only on the islands of New Zealand. • Actually: A practical machine learning tool developed by the University of Waikato in New Zealand. It is short for Waikato Environment for Knowledge Analysis. • Definition: A collection of machine learning algorithms for data mining tasks. • Language: It is written in Java and runs on almost any platform.
Introduction – Weka consists of • Explorer • Experimenter • Knowledge flow • Simple Command Line Interface(CLI) • Other tools and Visualization • Java interface
Explorer • WEKA’s main graphical user interface • Gives access to all its facilities using menu selection and form filling.(Data-Preprocess/Classify/Cluster/Associate/Select Attributes/Visualize) • 1.Data • 2. Operations of Explorer with a Classification example.
Explorer – Data(1) Attribute-Class Attribute Instance Instances *.xls *.csv Tips:weather.arff ( C:/Program Files/Weka/data/ ) • From files: CSV, ARFF, C4.5…(no *.xls) • Data loaded from URL or DB
Explorer – Data(2) • ARFF(Attribute-Relation File Format) • @relation <relation-name> • @attribute <attribute-name> <datatype> • numeric (real or integer numbers) • <nominal-specification> • string • date [<date-format>] • @data • % notes • More details: • http://www.cs.waikato.ac.nz/ • ~ml/weka/arff.html
Explorer – Operations with an example Input data Data preprocess Choose classifier Test options Run Result analysis
Explorer Summary Statistics Input data Select an attribute Visualization
Explorer Weka Filter Tune Parameters Apply the Filter Select a Filter
Explorer Tune Parameters Results Select a Classifier Decide how to evaluate Model list
Right-click on model to get Menu (save, visualize, etc)
Others – Experimenter Click it for Experimenter • Comparing different learning algorithms • ------on different datasets • ------with various parameter settings • ------and analyzing the performance statistics
Others – KnowledgeFlow Click it for KnowledgyFlow • The KnowledgeFlow provides an alternative to the Explorer as a graphical front end to Weka's core algorithms. • The KnowledgeFlow is a work in progress so some of the functionality from the Explorer is not yet available.
Others – Simple command line interface Click it for Simple CLI • All implementations of the algorithms have a uniform command-line interface. • java weka.classifiers.trees.J48 -t weather.arff
Conclusions 1.Explorer: Input data Data preprocess Choose classifier Test options Run Result analysis 2.Experimenter: It is necessary for further studies. 3.Make full use of: • 1. Java tips; • 2. WekaManual.pdf; (C:/Program Files/Weka/ ) • 3. Play it yourself!
Reference • Mitchell, T. Machine Learning, 1997 McGraw Hill. • Ian H. Witten, Eibe Frank, Len Trigg, Mark Hall, Geoffrey Holmes, and Sally Jo Cunningham (1999). Weka: Practical machine learning tools and techniques with Java implementations. • Ian H. Witten, Eibe Frank (2005). Data Mining: Practical Machine Learning Tools and Techniques (Second Edition, 2005). San Francisco: Morgan Kaufmann • Weka Homepage: http://www.cs.waikato.ac.nz/~ml/weka/ • Wekawiki: http://weka.wikispaces.com/ • Weka on SourceForge.net: http://sourceforge.net/projects/weka • WekaManual.pdf (C:\Program Files\Weka-3-6\WekaManual.pdf)