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Signal Enhancement Using Multivariate Classification Techniques and Physical Constraints. Ricardo Vilalta Puneet Sarda Gordon Mutchler Paul Padley. Outline. Introduction The Goal Kinematic Fitting Experiments. Introduction. Multivariate Classification Techniques Bayesian Functions
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Signal Enhancement Using Multivariate Classification Techniques and Physical Constraints Ricardo Vilalta Puneet Sarda Gordon Mutchler Paul Padley
Outline • Introduction • The Goal • Kinematic Fitting • Experiments
Introduction • Multivariate Classification Techniques • Bayesian Functions • Neural Networks • Decision Trees • Rule based • Experiments using CLAS • Detecting charged particles, inferring uncharged • Measure momentum, polar angle and azimuthal angle, time of flight • Infer mass • Using G1C dataset
Introduction • K*+ measurement is not the real interest. • We use it as a convenient test case to develop the multivariate techniques which will be used on new data. Reactions we will look for Background Reactions
The Goal • Empirical comparison of several multivariate classification techniques for signal enhancement • Use of Kinematic Fitting to enhance original feature representation • Effect of cost matrices in generalization performance
Kinematic Fitting • Mathematical procedure • Takes advantage of constraints such as energy/momentum conservation • improve measured quantities • provide a means to cut background
Experiments • WEKA • Characteristics of Data • Feature Selection • Initial Classification • Cost Sensitive Classification
Characteristics of Data • 1000 MC Signal Samples • ~6000 MC Background Samples • ~13,500 Real Samples • 45 Attributes • Attribute 1 – 4 : Confidence Levels • Attribute 5 : Total Energy Level • Attribute 6 – 44 : (3 measured + 5 derived) Four Vectors + Mass**2 • Attribute 45 : Class (Signal/Background)
Feature Selection • Analysis using Information Gain • Comparison of top 5/10/15 attributes • Final selection = top 5
Random Forest • Grows many classification trees • Voting among trees • Growing a tree • Sampling on N cases • M input variables • No pruning • Error rate
Summary • Monte Carlo Data • Kinematic Fitting • Learning Algorithm • Real Data • Signal Enhancement