Cluster analysis 1 Cluster validity 1 Clusterings 1 Day clustering Dimensionality reduction 1 External index 1 Forecasting 1 Information management 1 Intelligent systems 1 Internal index 1 K-means clustering 1 Learning systems 1 Network-wide 1 Pattern recognition 1 Reduction 1 Representative days 1 Scalability 1 Short term prediction 1 clustering 1 day clustering 1 dimensionality reduction 1 external indices 1 internal indices 1 network-wide 1 prediction 1