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US6182058B1 Expired / Lapsed US ⏱️ 0.0 years remaining

Bayes rule based and decision tree hybrid classifier

Assignee: RPX Corp
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Filing: 1997-02-28
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Granted: 2001-01-30
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Expires: 2017-02-28
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Abstract

Abstract The present invention provides a hybrid classifier, called the NB-Tree classifier, for classifying a set of records. According to the present invention, the NB-Tree classifier includes a Decision-Tree structure having zero or more decision-nodes and one or more leaf-nodes. At each decision-node, a test is performed based on one or more attributes. At each leaf-node, a classifier based on Bayes Rule classifies the records. Furthermore, the present invention provides a method for inducing the NB-Tree classifier from a set of labeled instances. To induce the NB-Tree classifier, a utility C 1 of a Bayes classifier at a root-node is first estimated. Next, a utility D 1 of a split into a plurality of child-nodes with a Bayes classifier at the child-nodes is estimated. The utility of a split is the weighted sum of the utility of the child-nodes, where the weight given to a child-node is proportional to the number of instances that go down that child-node. Next, it is determined if C 1 is higher than D 1 . If C 1 is higher than D 1 , the root-node is transformed into a leaf-node with a Bayes classifier. If C 1 is not higher than D 1 , the root-node is transformed into a decision-node, and the instances are partitioned into a plurality of child-nodes. The method then recursively performs the previous steps for each child-node as if it is a root-node. The present invention approximates whether a generalization accuracy for a Naive-Bayes classifier at each leaf-node is higher than a single Naive-Bayes classifier at the decision-node. According to one embodiment of the present invention, to avoid splits with little value, a split is defined to be significant if the relative (not absolute) reduction in error is greater than 5% and there are at least 30 instances in the node.

Inventors

  • 👤 Ron Kohavi

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 18:18
CPC Classifications
G; G06; G06F; G06F18/00; G06F18/20; G06F18/24; G06F18/243; G06F18/24323

Claims Analysis

Total Claims: 20
Claim 1
Independent Claim 103 words
A hybrid classifier comprising a computer program residing in a computer readable medium for classifying a set of instances, each instance having a plurality of attributes, comprising: a decision tree structure having zero or more decision-nodes and one or more leaf-nodes, wherein at each of said decision-nodes, a test is performed based on one or more attributes; and a classifier based on Bayes Rule at each of said leaf-nodes, each leaf-node being connected to a decision-node of the decision tree, said classifier classifying said instances at each leaf-node according to Bayes Rule; wherein said hybrid classifier outputs a label for each classified instance.
Claim 2
Dependent Claim 103 words
A hybrid classifier comprising a computer program residing in a computer readable medium for classifying a set of instances, each instance having a plurality of attributes, comprising: a decision tree structure having zero or more decision-nodes and one or more leaf-nodes, wherein at each of said decision-nodes, a test is performed based on one or more attributes; and a classifier based on Bayes Rule at each of said leaf-nodes, each leaf-node being connected to a decision-node of the decision tree, said classifier classifying said instances at each leaf-node according to Bayes Rule; wherein said hybrid classifier outputs a label for each classified instance.
Claim 3
Independent Claim 91 words
A method for executing a hybrid classifier residing in a computer readable medium, said hybrid classifier having at least one decision-node and at least one leaf-node to classify a set of instances, each having a plurality of attributes, the method comprising the steps of: performing a test, based on one or more of said attributes, at each of said decision-nodes; classifying said instances according to Bayes Rule, at each leaf-node, by processing of a Bayes Rule classifier residing in said computer readable medium; and outputting a label for each classified instance.
Claim 4
Independent Claim 91 words
A method for executing a hybrid classifier residing in a computer readable medium, said hybrid classifier having at least one decision-node and at least one leaf-node to classify a set of instances, each having a plurality of attributes, the method comprising the steps of: performing a test, based on one or more of said attributes, at each of said decision-nodes; classifying said instances according to Bayes Rule, at each leaf-node, by processing of a Bayes Rule classifier residing in said computer readable medium; and outputting a label for each classified instance.
Claim 5
Independent Claim 176 words
A method of inducing a hybrid classifier from a set of labeled instances, each instance having a plurality of attributes, the method comprising the steps of: (a) estimating utility C 1 of a Bayes classifier at the root-node; (b) estimating utility D 1 of a split into a plurality of child-nodes with a Bayes classifier at the child-nodes; (c) determining if C 1 is higher than D 1 , if C 1 is higher than D 1 , making said root-node a leaf-node with a Bayes classifier; if C 1 is not higher than D 1 , making said root node a decision-node, and partitioning the instances into a plurality of child-nodes; and (d) recursively performing steps (a) through (c) for each child-node as if it is a root-node to obtain said hybrid classifier; wherein said induced hybrid classifier has a root-node, zero or more decision-nodes, zero or more child-nodes and one or more leaf-nodes, said root-node being either a decision-node or a leaf-node; and (e) storing said induced hybrid classifier in a computer readable medium.
Claim 6
Independent Claim 176 words
A method of inducing a hybrid classifier from a set of labeled instances, each instance having a plurality of attributes, the method comprising the steps of: (a) estimating utility C 1 of a Bayes classifier at the root-node; (b) estimating utility D 1 of a split into a plurality of child-nodes with a Bayes classifier at the child-nodes; (c) determining if C 1 is higher than D 1 , if C 1 is higher than D 1 , making said root-node a leaf-node with a Bayes classifier; if C 1 is not higher than D 1 , making said root node a decision-node, and partitioning the instances into a plurality of child-nodes; and (d) recursively performing steps (a) through (c) for each child-node as if it is a root-node to obtain said hybrid classifier; wherein said induced hybrid classifier has a root-node, zero or more decision-nodes, zero or more child-nodes and one or more leaf-nodes, said root-node being either a decision-node or a leaf-node; and (e) storing said induced hybrid classifier in a computer readable medium.
Claim 7
Dependent Claim 22 words
The method of inducing according to claim 3 , wherein said Bayes classifier is Naive-Bayes built after all attributes have been discretized.
Claim 8
Dependent Claim 37 words
The method of inducing according to claim 3 , wherein said utility estimate of a split in step (b) is based on an accuracy estimation selected from the group consisting of at least holdout, cross-validation and bootstrap.
Claim 9
Dependent Claim 36 words
The method of inducing according to claim 3 , wherein estimating the utility D 1 of a split based on one or more attributes further comprises the step of determining a threshold split for ordered attributes.
Claim 10
Dependent Claim 32 words
The method of inducing according to claim 3 , wherein said partitioning the instances into a plurality of child further comprises the step of performing a multiway split, i.e., a non-binary split.
Claim 11
Dependent Claim 50 words
The method of inducing according to claim 3 , wherein the utility of a split into a plurality of child-nodes is the weighted sum of the utility of the child-nodes, where the weight given to each child-node is proportional to the number of instances that go down to that node.
Claim 12
Independent Claim 229 words
A method of inducing a hybrid classifier from a set of labeled instances, each instance having a plurality of attributes, the method comprising the steps of: (a) estimating the Naive-Bayes accuracy A for the root-node; (b) if X i is ordered, determining a threshold; (c) determining the accuracy estimate u(X i ) of a split into a plurality of child-nodes based on each attribute X i at said root-node; (d) determining the attribute j with the highest accuracy, said j=arg max i u(X i ), said u(X j ) being the accuracy of the attribute j; (e) if u(X j ) is not higher than A, making said root-node a leaf-node, creating a Naive-Bayes classifier at said leaf-node, if u(X j ) is higher than A, making said root-node a decision-node based on X i , partitioning the instances into a plurality of child-nodes according to X j , said partitioning includes a multiway split when Xj is discrete or has been discretized; and (f) recursively performing steps (a) through (e) for each child-node X j as if it is a root-node thereby inducing a hybrid classifier; wherein said induced hybrid classifier has a root-node, zero or more decision-nodes, zero or more child-nodes and one or more leaf-nodes, said root-node being either a decision-node or a leaf-node; and (g) storing said induced hybrid classifier in a computer readable medium.
Claim 13
Independent Claim 229 words
A method of inducing a hybrid classifier from a set of labeled instances, each instance having a plurality of attributes, the method comprising the steps of: (a) estimating the Naive-Bayes accuracy A for the root-node; (b) if X i is ordered, determining a threshold; (c) determining the accuracy estimate u(X i ) of a split into a plurality of child-nodes based on each attribute X i at said root-node; (d) determining the attribute j with the highest accuracy, said j=arg max i u(X i ), said u(X j ) being the accuracy of the attribute j; (e) if u(X j ) is not higher than A, making said root-node a leaf-node, creating a Naive-Bayes classifier at said leaf-node, if u(X j ) is higher than A, making said root-node a decision-node based on X i , partitioning the instances into a plurality of child-nodes according to X j , said partitioning includes a multiway split when Xj is discrete or has been discretized; and (f) recursively performing steps (a) through (e) for each child-node X j as if it is a root-node thereby inducing a hybrid classifier; wherein said induced hybrid classifier has a root-node, zero or more decision-nodes, zero or more child-nodes and one or more leaf-nodes, said root-node being either a decision-node or a leaf-node; and (g) storing said induced hybrid classifier in a computer readable medium.
Claim 14
Independent Claim 201 words
A system for inducing a hybrid classifier from a set of labeled instances, each instance having a plurality of attributes, said hybrid classifier having a root-node, one or more decision-nodes, one or more child-nodes and one or more leaf-nodes, said root-node being either a decision-node or a leaf-node in appropriate circumstances, comprising: at least one processor coupled to a storage means, the one at least processor includes: (a) means for estimating utility C 1 of a Bayes classifier at the root-node; (b) means for estimating utility D 1 of a split into a plurality of child-nodes with a Bayes classifier at the child-nodes; (c) means for determining if C 1 is higher than D 1 ; (d) means for making said root-node a leaf-node with a Bayes classifier if C 1 is higher than D 1 ; (e) means for making said root node a decision-node, and partitioning the instances into a plurality of child-nodes, if C 1 is not higher than D 1 ; and (f) means for recursively initiating operation of each of means (a) through (e) for each child-node as if it is a root-node thereby inducing said hybrid classifier which can be stored in said storage means.
Claim 15
Independent Claim 201 words
A system for inducing a hybrid classifier from a set of labeled instances, each instance having a plurality of attributes, said hybrid classifier having a root-node, one or more decision-nodes, one or more child-nodes and one or more leaf-nodes, said root-node being either a decision-node or a leaf-node in appropriate circumstances, comprising: at least one processor coupled to a storage means, the one at least processor includes: (a) means for estimating utility C 1 of a Bayes classifier at the root-node; (b) means for estimating utility D 1 of a split into a plurality of child-nodes with a Bayes classifier at the child-nodes; (c) means for determining if C 1 is higher than D 1 ; (d) means for making said root-node a leaf-node with a Bayes classifier if C 1 is higher than D 1 ; (e) means for making said root node a decision-node, and partitioning the instances into a plurality of child-nodes, if C 1 is not higher than D 1 ; and (f) means for recursively initiating operation of each of means (a) through (e) for each child-node as if it is a root-node thereby inducing said hybrid classifier which can be stored in said storage means.
Claim 16
Dependent Claim 233 words
A computer program product comprising: a computer readable medium having computer readable program code means embodied in said medium for causing inducement of a hybrid classifier from a set of labeled instances, each instance having a plurality of attributes, said hybrid classifier having a root-node, one or more decision-nodes, one or more child-nodes and one or more leaf-nodes, said root-node being either a decision-node or a leaf-node in appropriate circumstances, said computer program product including: (a) computer readable program code means for estimating utility C 1 of a Bayes classifier at the root-node; (b) computer readable program code means for estimating utility D 1 of a split into a plurality of child-nodes with a Bayes classifier at the child-nodes; (c) computer readable program code means for determining if C 1 is higher than D 1 ; (d) computer readable program code means for making said root-node a leaf-node with a Bayes classifier if C 1 is higher than D 1 ; (e) computer readable program code means for making said root node a decision-node, and partitioning the instances into a plurality of child-nodes according to the tests if C 1 is not higher than D 1 ; and (f) computer readable program code means for recursively initiating operation of each of computer readable program code means (a) through (e) for each child-node as if it is a root-node thereby inducing said hybrid classifier.
Claim 17
Dependent Claim 233 words
A computer program product comprising: a computer readable medium having computer readable program code means embodied in said medium for causing inducement of a hybrid classifier from a set of labeled instances, each instance having a plurality of attributes, said hybrid classifier having a root-node, one or more decision-nodes, one or more child-nodes and one or more leaf-nodes, said root-node being either a decision-node or a leaf-node in appropriate circumstances, said computer program product including: (a) computer readable program code means for estimating utility C 1 of a Bayes classifier at the root-node; (b) computer readable program code means for estimating utility D 1 of a split into a plurality of child-nodes with a Bayes classifier at the child-nodes; (c) computer readable program code means for determining if C 1 is higher than D 1 ; (d) computer readable program code means for making said root-node a leaf-node with a Bayes classifier if C 1 is higher than D 1 ; (e) computer readable program code means for making said root node a decision-node, and partitioning the instances into a plurality of child-nodes according to the tests if C 1 is not higher than D 1 ; and (f) computer readable program code means for recursively initiating operation of each of computer readable program code means (a) through (e) for each child-node as if it is a root-node thereby inducing said hybrid classifier.
Claim 18
Dependent Claim 18 words
The hybrid classifier of claim 1 , wherein said decision tree structure includes at least one decision node.
Claim 19
Dependent Claim 110 words
A hybrid classifier that classifies a set of instances, each instance having a plurality of attributes, the hybrid classifier comprising: a decision tree structure having zero or more decision-nodes and one or more leaf-nodes, wherein at each of said decision-nodes, a test is performed based on one or more attributes; and a classifier based on Bayes Rule at each of said leaf-nodes, each leaf-node being connected to a decision-node of the decision tree, said classifier classifying said instances at each leaf-node according to Bayes Rule; wherein said hybrid classifier outputs a label for each classified instance, and wherein said hybrid classifier comprises at least one of software, firmware, and hardware.
Claim 20
Dependent Claim 110 words
A hybrid classifier that classifies a set of instances, each instance having a plurality of attributes, the hybrid classifier comprising: a decision tree structure having zero or more decision-nodes and one or more leaf-nodes, wherein at each of said decision-nodes, a test is performed based on one or more attributes; and a classifier based on Bayes Rule at each of said leaf-nodes, each leaf-node being connected to a decision-node of the decision tree, said classifier classifying said instances at each leaf-node according to Bayes Rule; wherein said hybrid classifier outputs a label for each classified instance, and wherein said hybrid classifier comprises at least one of software, firmware, and hardware.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2004-01-30 2004-07-31 2005-01-30 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2008-01-30 2008-07-31 2009-01-30 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2012-01-30 2012-07-31 2013-01-30 $7700.00 Window Closed / Lapsed

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