Download presentation
Presentation is loading. Please wait.
Published byPhoebe Jones Modified over 9 years ago
1
Support Vector Machine Data Mining Olvi L. Mangasarian with Glenn M. Fung, Jude W. Shavlik & Collaborators at ExonHit – Paris Data Mining Institute University of Wisconsin - Madison
2
What is a Support Vector Machine? An optimally defined surface Linear or nonlinear in the input space Linear in a higher dimensional feature space Implicitly defined by a kernel function K(A,B) C
3
What are Support Vector Machines Used For? Classification Regression & Data Fitting Supervised & Unsupervised Learning
4
Principal Topics Knowledge-based classification Incorporate expert knowledge into a classifier Breast cancer prognosis & chemotherapy Classify patients on basis of distinct survival curves Isolate a class of patients that may benefit from chemotherapy Multiple Myeloma detection via gene expression measurements Drug discovery based on gene macroarray expression Joint work with ExonHit
5
Support Vector Machines Maximize the Margin between Bounding Planes A+ A-
6
Principal Topics Knowledge-based classification (NIPS*2002)
7
Conventional Data-Based SVM
8
Knowledge-Based SVM via Polyhedral Knowledge Sets
9
Incoporating Knowledge Sets Into an SVM Classifier This implication is equivalent to a set of constraints that can be imposed on the classification problem. Suppose that the knowledge set: belongs to the class A+. Hence it must lie in the halfspace : We therefore have the implication:
10
Numerical Testing The Promoter Recognition Dataset Promoter: Short DNA sequence that precedes a gene sequence. A promoter consists of 57 consecutive DNA nucleotides belonging to {A,G,C,T}. Important to distinguish between promoters and nonpromoters This distinction identifies starting locations of genes in long uncharacterized DNA sequences.
11
The Promoter Recognition Dataset Numerical Representation Simple “1 of N” mapping scheme for converting nominal attributes into a real valued representation: Not most economical representation, but commonly used.
12
The Promoter Recognition Dataset Numerical Representation Feature space mapped from 57-dimensional nominal space to a real valued 57 x 4=228 dimensional space. 57 nominal values 57 x 4 =228 binary values
13
Promoter Recognition Dataset Prior Knowledge Rules Prior knowledge consist of the following 64 rules:
14
Promoter Recognition Dataset Sample Rules where denotes position of a nucleotide, with respect to a meaningful reference point starting at position and ending at position Then:
15
The Promoter Recognition Dataset Comparative Algorithms KBANN Knowledge-based artificial neural network [Shavlik et al] BP: Standard back propagation for neural networks [Rumelhart et al] O’Neill’s Method Empirical method suggested by biologist O’Neill [O’Neill] NN: Nearest neighbor with k=3 [Cost et al] ID3: Quinlan’s decision tree builder[Quinlan] SVM1: Standard 1-norm SVM [Bradley et al]
16
The Promoter Recognition Dataset Comparative Test Results
17
Principal Topics Breast cancer prognosis & chemotherapy
18
Kaplan-Meier Curves for Overall Patients: With & Without Chemotherapy
19
Breast Cancer Prognosis & Chemotherapy Good, Intermediate & Poor Patient Groupings (6 Input Features : 5 Cytological, 1 Histological) (Clustering: Utilizes 2 Histological Features &Chemotherapy) 253 Patients (113 NoChemo, 140 Chemo) Cluster 113 NoChemo Patients Use k-Median Algorithm with Initial Centers: Medians of Good1 & Poor1 69 NoChemo Good 44 NoChemo Poor 67 Chemo Good 73 Chemo Poor Good Poor Intermediate Cluster 140 Chemo Patients Use k-Median Algorithm with Initial Centers: Medians of Good1 & Poor1 Good1: Lymph=0 AND Tumor<2 Compute Median Using 6 Features Poor1: Lymph>=5 OR Tumor>=4 Compute Median Using 6 Features Compute Initial Cluster Centers
20
Kaplan-Meier Survival Curves for Good, Intermediate & Poor Patients 82.7% Classifier Correctness via 3 SVMs
21
Kaplan-Meier Survival Curves for Intermediate Group Note Reversed Role of Chemotherapy
22
Multiple Myeloma Detection Multiple Myeloma is cancer of the plasma cell Plasma cells normally produce antibodies Out of control plasma cells produce tumors When tumors appear in multiple sites they are called Multiple Myeloma Dataset 105 patients: 74 with MM, 31 healthy Each patient is represented by 7008 gene measurements taken from plasma cell samples For each one of the 7008 gene measurements Absolute Call (AC): Absent (A), Marginal (M) or Present (P) Average Difference (AD): Positive or negative number
23
Multiple Myeloma Data Representation A 1 0 0 M 0 1 0 P 0 0 1 AMP 7008 X 3 = 21024 AD 7008 Total = 28,032 per patient 104 Patients: 74 MM + 31 Healthy 104 X 28,032 Data Matrix A
24
Multiple Myeloma 1-Norm SVM Linear Classifier Leave-one-out-correctness (looc) = 100% Average number of features used = 7 per fold Total computing time for 105 folds = 7892 sec. Overall number of features used in 105 folds= 7
25
Breast Cancer Treatment Response Joint with ExonHit - Paris (Curie Dataset) 35 patients treated by a drug cocktail 9 partial responders; 26 nonresponders 25 gene expressions out of 692, selected by Arnaud Zeboulon Most patients had 3 replicate measurements 1-Norm SVM classifier selected 14 out of 25 gene expressions Leave-one-out correctness was 80% Greedy combinatorial approach selected 5 genes out of 14 Separating plane obtained in 5-dimensional gene-expression space Replicates of all patients except one used in training Average of replicates of patient left out used for testing Leave-one-out correctness was 33 out of 35, or 94.2%
26
Separation of Convex Hull of Replicates of: 10 Synthetic Nonresponders & 4 Synthetic Partial Responders
27
Linear Classifier in 3-Gene Space 35 Patients with 93 Replicates 26 Nonresponders & 9 Partial Responders
28
Conclusion New approaches for SVM-based classification Algorithms capable of classifying data with few examples in very large dimensional spaces Typical of microarray classification problems Classifiers based on both abstract prior knowledge as well as conventional datasets Identification of breast cancer patients that can benefit from chemotherapy Useful tool for drug discovery
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.