Saturday, November 12, 2005

Meclazine And Vertigo



One of the practical applications of Artificial Neural Networks (ANN), is the classification of data, understood as a process of searching for properties common to a number of objects a domain of knowledge, depending on the values \u200b\u200bof certain attributes. Within the issue of automatic qualification, while the alternative process of more general processes encompassed within what is known as "machine learning", one of the learning algorithms known, based on "examples", is called ID3, or "Iterative dichotomized (version) 3" (JR Quinlan, 1979). Work with symbolic data, as opposed numerical data, and is based on obtaining a decision tree (see Annex
  • ), from which derive a set of production rules, can represent a particular domain or universe, producing independent knowledge of that domain (the learning system from an initial state chosen domain in which there is no knowledge base, extracting patterns common among the examples used, from which generates a knowledge base application that domain). The decision tree can therefore classify the input data. We can distinguish two types of learning processes: supervised
  • : examples or explanations "were provided to the system by an external subject. This category ratings data based on decision trees based on examples, such as learning algorithm ID3 . Unsupervised
  • : examples or "comments" are created by the system itself. This category grouping processes data or data clustering (or just clustering ).
  • Based on a conceptual level of abstraction higher, the so-called "machine learning" or learning machine, it is possible to distinguish two types of learning: rote learning

    ID3 of Quinlan.

    Most of the heuristics used for the determination of decision trees through learning algorithms, are based on the mathematical theory of information ( C .

    Shannon, W. Weaver, Bell Laboratories, 1948) [1
    • ] [ 2]. Heuristics are criteria, methods or principles for deciding, from among several alternative courses of action, which will be most effective to achieve certain goal. Restrict the number of evaluations, and therefore impact on improving the search time for solutions. Entropíay amount of information are two concepts that come together in the field of heuristics. About Entropíay amount of information, see Uncle Petros
    • : [1 ] [ 2 ] [
    3] [4

    ]. ID3 algorithm

    generates what is called the rules "hard", ie those who only see two possible states (true or false, positive-negative, 0-1, etc.), And which are both a bivalent character, unlike the rules "fuzzy", which can represent an infinite range of values \u200b\u200bbetween two ends of a scale as those obtained using algorithms ID3

    "extended" (ID4, ID5, ID5R , C4.5, C5, etc.).

    ID3 Algorithm Pseudocode

    :

    If all examples belong to E same class C, then arbol1 \u0026lt;- node labeled with C

    But

    If a = f, then C \u0026lt;- class majority of the examples of E arbol1 \u0026lt;- node labeled with C But A \u0026lt;- best attribute of a arbol1 \u0026lt;- node labeling with A For each v belonging to the values \u200b\u200bof A, do VAS \u0026lt;- examples of E with the value v for attribute A If Eav = f, then ; arbol2 \u0026lt;- node labeled with the majority class in E But arbol2 \u0026lt;- ID3 (VAS, a-{A}) arbol1 \u0026lt;- add to the arbol2 arbol1 through a branch labeled with v arbol1 Return Another representation in pseudocode algorithm ID3 :

    -Decision-Tree Learning (

    Examples, Attributes ,

    Default)

    returns a decision tree

    IF there
    Examples
    , Default
    return


    ELSE IF

    if all examples have the same classification
    ,

    return
    classification,



    ELSE IF s = Attribute

    empty

    return Majority ( Examples

    ) ELSE

    best-atr \u0026lt;- choose-attribute (Attributes , Examples
    )
    tree \u0026lt;- new decision tree rooted in best-atr
    FOR EACH value v [i] best-atr DO Examples
    [i] \u0026lt;- Examples { items with better-atr = v [i]} Subar \u0026lt;--Decision-Tree Learning (examples [i], Attributes
    - best-atr, Majority ( Examples ))
    add branch the tree with label v [i] and subtree Subar OD return tree learning processes that make use of the classification of data by discovery of patterns, are widely used in what is known as "Data Mining", Castilian data mining, data mining or knowledge discovery in databases, terminological diversity about which there is discussion.
    Maximiliano del Rio is the author of a version written in Prolog language learning algorithm ID3
    . The files for this implementation (library Ratings ) can be located either in the source code section of
    programacion.com
    (compressed into a "zip"), or personal space that the author has the "Wiki " of SWI-Prolog
    . In " guia.txt " describes the management of this implementation
    ID3 algorithm in Prolog, which uses the ODBC

    interface to query the tables of the database selected, the examples are obtained for the generation of production rules. Is also attached file " clasif.pl " program "Data Mining" that uses the ID3 algorithm
    endowed GUI using the native library XPCE

    .

    "[...]

    program that uses the above library [...] helps generate the rules and displays the textual and graphical rules obtained, also shows a trace of how the algorithm works. " Source

    This GUI is opened releasing the target "? - Main." on the command line SWI-Prolog, once compiled the program. Finally, the library " compila.pl " contains predicates that allow generate an executable for Windows from the results, using SWI-Prolog. For a rather wide on the Prolog implementation of automatic learning processes in general and inductive learning by decision trees in particular (data classification) is highly recommended reading Chapter 18, "Machine Learning", the (now classic) work of Ivan Bratko, "Prolog: Programming for Artificial Intelligence" (2 nd ed. Addison-Wesley, 1994, ISBN: 0-201-41606 - 9). On decision trees specifically point is 18.6, "Induction of decision trees." There is thus itself a repository of machine learning algorithms written in Prolog, Prolog library of machine learning algorithms , albeit somewhat outdated, since the last update seems to date from 1994, maintained by Thomas Hoppe (Fraunhofer-Gesellschaft , Technical University of Berlin ). The programs are written using the syntax and, in most cases, the predefined predicates (built-in predicates ) specified in Prolog by Clocksin and Mellish described, known as standard Edinburgh, based in turn on the DECSYSTEM-10 (D. Warren, F. Pereira and L. Pereira), to thus ensure the greatest possible degree of compatibility between versions of the language. algorithm implementations ID3 are located in the " RTD" (see in any case the file "Readme " for more information). More information:

    ID3 algorithm JR Quinlan
    (document translated by JA Fernandez,

    PDF, compressed in a zip). Basics of Symbolic Learning (JG Boticario).

    Learning classifiers (Berzal F. Galiano, in PDF). ART: An alternative method for constructing decision trees (Berzal F. Galiano, in PDF). ART: An alternative method for constructing decision trees (Berzal F. Galiano, 2002; doctoral thesis in PDF). RTD Torgos ID3-like system based on the gain-ratio measure ( ID3 algorithm written in Edinburgh Prolog syntax.) This code is located in the directory on Machine Learning

    extensions

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