Twitter related problems: 1. Named Entity Recognition (NER) , 2. Relation Extraction 3. Classification 4. Event Detection , , , 5. Event Tracking 6. Geo search and visualization 7. Recommender , 8. Trend Mining 9. Difusion of topics , , 10. Prediction , , , , 11. Emergence , Theoretical aspects: 1. Attributed Graph Model , 2. Rezidual Analysis of Attributed Graphs 3. Sub-graph matching , 4. Diffusion wavelets transform , 5. Detection Theory 6. Complex networks 7. Spectral analysis of graphs 8. Signal Processing 9. Prediction Annalytics 10. Tensors Problems addresed in the framework of DSP on graphs: 1. Mathematical model of Twitter as a dynamic attributed graph with streams attached to vertexes. 2. Subgraph matching. 3. Twitter diffusion of topics or hash terms. 4. Tweet classification. 5. Quering a corpus of dependencies parses of sentences viewed as graphs. 6. Integrated search of documents, multimedia archives and geographic data. 7. Detection Theory on twitter graphs. 8. Recommender Systems. + NER 9. Event Detection. 10. Predicting Event 11. Event Summarization 12. Event Association 13. Early Warning System 14. Big Data Implementation. Big Data Application Layer for Graphs: 1. Search/Query 2. 1. Graph Analytics 2. PageRank 3. Subgraph Detection 4. Belief Propagation 5. Clustering/Classification