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kddml.Operators.Postprocessing.SEQUENCE_TIMESTAMP_FILTER_RESOLVER Class Reference

Inheritance diagram for kddml.Operators.Postprocessing.SEQUENCE_TIMESTAMP_FILTER_RESOLVER:

kddml.Operators.Postprocessing.PostProcessingResolver kddml.Operators.OperatorResolver kddml.Operators.HWResourcesDescription List of all members.

Public Member Functions

KDDMLObject execute (Hashtable< String, KDDMLScalarManager > settings, Vector< KDDMLObject > arguments) throws ResolverException, KDDMLCoreException
KDDMLObjectType getArgumentType (int i)

Detailed Description

Given a set of sequential patterns and a time-stamp table, the operator returns the patterns satisfying a specific condition.
Condition concerns a time-stamp constraint that is defined only in sequence databases, where each transaction in every sequence has a continuous time-stamp, i.e., the timestamp column of the input data source must be numeric. The constraint can be a duration constraint or a gap constraint.
The first one requires that the pattern appears frequently in the sequence database in such a way that the time-stamp difference between the first and last transactions in the pattern are either longer or shorter than a given period (e.g., “only patterns in which every event occurred within a month from the first one”).
The gap constraint requires that the pattern occurs frequently in the sequence database such that the time-stamp difference between every two adjacent transactions must be either longer or shorter than a given gap (e.g., “only patterns in which the time gap between adjacent events occurred within one day). In both cases, the period is given as interval expressed via XML attributes. This operator is support-related, i.e. the given condition is applied to check whether a sequence matches a transaction. In order to find whether a sequential pattern satisfies these constraints, one needs to examine the sequence database. In other terms, a pattern keeps being frequent only if the number of data sequences (transactions) supporting it and satisfying the condition is greater than the minimum support. The support threshold is commonly expressed in the model and it can be specified in terms of absolute count or percentage.

Title: KDDML

Description: Knowledge Discovery in Database Environment

Copyright: Copyright (c) 2003 - 2005

Company: Universita' di Pisa - Dipartimento di Informatica

Author:
Daniele Cerra
Version:
2.0.16


Member Function Documentation

KDDMLObject kddml.Operators.Postprocessing.SEQUENCE_TIMESTAMP_FILTER_RESOLVER.execute Hashtable< String, KDDMLScalarManager settings,
Vector< KDDMLObject arguments
throws ResolverException, KDDMLCoreException [virtual]
 

Returns the result of evaluating the operator over the passed arguments and attributes.
Attributes are given as hashtable, where the key is the name of the XML attribute related to the operator and the value is a KDDMLScalar object containing the attribute value. Attribute value is checked by the interpreter layer and it is correct.
Arguments are given as vector of KDDMLOjbect. Types of arguments are correct, as required by the getArgumentType(int i) method.
Implementations of the execute method can be distinguished according to the type of operator.

Parameters:
settings Hashtable the attributes related to the operator. The key of the hashtable is the name of the attribute. The value of the hashtable is a KDDMLScalar representing the value of the attribute.
arguments Vector the list of arguments as KDDMLObject.
Returns:
KDDMLObject the result of evaluating the operator.
Exceptions:
ResolverException if a resolving error occurs.
KDDMLCoreException if a level core error occurs.

Implements kddml.Operators.OperatorResolver.

KDDMLObjectType kddml.Operators.Postprocessing.SEQUENCE_TIMESTAMP_FILTER_RESOLVER.getArgumentType int  i  )  [virtual]
 

Returns the expected type of the i-th argument of the operator. Returns null if the operator do not admit argument as i-th child.

Parameters:
i int
Returns:
KDDMLObjectType

Implements kddml.Operators.OperatorResolver.


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