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Data mining in wireless sensor networks based on artificial neural-networks algorithms. Authors: Andrea Kulakov and Danco Davcev Presentation by: Niyati Parikh. Motivation.
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Data mining in wireless sensor networks based on artificial neural-networks algorithms Authors: Andrea Kulakov and Danco Davcev Presentation by: Niyati Parikh
Motivation • Centralized data clustering in sensor networks is difficult, not scalable, limited communication bandwidth, limited power supply, data redundancy • Advantage of Neural Networks: demand of compressed summaries of large spatio-temporal data, similarity queries – finding similar patterns or detecting correlations • Unsupervised learning ANN perform dimensionality reduction or pattern clustering
Adaptive Resonance Theory(ART1) Attentional subsystem F2 Category layer reset Orienting subsystem - F1 p Comparison layer + F0 Input layer Binary input
Adaptive Resonance Theory(ART1) Attentional subsystem F2 Category layer Ti = | wi . x | reset B + | wi | Orienting subsystem - F1 p Comparison layer + F0 Input layer Binary input
Adaptive Resonance Theory(ART1) Attentional subsystem F2 Category layer Ti = | wi . x | reset B + | wi | Orienting subsystem - F1 p Comparison layer | wi . x | + | x | F0 Input layer Binary input
Adaptive Resonance Theory(ART1) Attentional subsystem F2 Category layer Winew = Ti = | wi . x | reset B + | wi | Orienting subsystem - F1 p Comparison layer | wi . x | + | x | F0 Input layer Binary input
ART1 • Continue finding an F2 node until prototype matches the input well enough or else allocate a new F2 node • Capable of refining learned categories and finding new patterns • Value of p: higher the vigilance level, more specific clusters
FuzzyART • Same as ART1, but replace intersection operator of ART1 with fuzzy set theory conjunction MIN operator ^ • ART1 and FuzzyART use complement coding – concatenate input pattern b with b’ or bi with (1-bi) • Look at the features consistently present or absent from a pattern
Proposed architectures of sensor networks Clusterhead collecting all sensor data from its cluster of units
One clusterhead collecting and classifying the data after they are once classified at the lower level
Comparison • Tested data robustness – made one sensor defective • Architecture1: trained with p=0.93 and tested with p = 0.90 • Architecture2: trained with p=0.80 and tested with p = 0.70 • Architecture2 makes 0.75% classification error
Future work • Applying ARTMAP and FuzzyARTMAP - supervised learning versions