Tutorial: Big Data Algorithms and Applications Under Hadoop KUNPENG ZHANG SIDDHARTHA BHATTACHARYYA

Transcription

1 Tutorial: Big Data Algorithms and Applications Under Hadoop KUNPENG ZHANG SIDDHARTHA BHATTACHARYYA August 7, 2014

2 Schedule I. Introduction to big data (8:00 8:30) II. Hadoop and MapReduce (8:30 9:45) III. Coffee break (9:45 10:00) IV. Distributed algorithms and applications (10:00 11:40) V. Conclusion (11:40 12:00)

3 V. Conclusion

4 Conclusion What is big data? Why big matters to you? What are techniques for big data analytics? Hadoop and MapReduce Clustering algorithm: K-means Topic modeling algorithm: LDA Social network analysis: centrality

5 What is big data? Five Vs Volume: the size of data Velocity: the change speed of data, streaming generating data Variety: the format of data is various Veracity: the truth of data Value: companies can benefit from big data analysis

6 Why big data matters to you? Big data analytics has been occurred in every domain, including finance, government, science, healthcare, IT, etc. Big data becomes a hot word in job descriptions Many companies benefit from big data analysis

7 Techniques in big data analytics Machine learning Text/web mining Distributed computing Social network analysis Natural language processing Visualization Optimization

8 Hadoop and MapReduce Hadoop is a platform MapReduce is a computing mechanism

9 HDFS architecture

10 MapReduce framework Per cluster node: Single JobTracker per master Responsible for scheduling the jobs component tasks on the slaves Monitor slave progress Re-execute failed tasks Single TaskTracker per slave Execute the task as directed by the master

11 Hadoop data flow

12 K-Means k initial "means" (in this case k=3) are randomly generated within the data domain (shown in color). k clusters are created by associating every observation with the nearest mean. The partitions here represent the Voronoi diagram generated by the means. The centroid of each of the k clusters becomes the new mean. Steps 2 and 3 are repeated until convergence has been reached.

13 Topic modeling algorithm: LDA α V-dimensional Dirichlet Joint distribution θ d Z d,n W d,n N d topic proportions observed word for document topic assignment for word D β k topics K η K-dimensional Dirichlet

14 Network analysis: centrality Degree centrality of a node in a network is the number of links (vertices) incident on the node. Closeness centrality determines how close a node is to other nodes in a network by measuring the sum of the shortest distances (geodesic paths) between that node and all other nodes in the network. Betweenness centrality determines the relative importance of a node by measuring the amount of traffic flowing through that node to other nodes in the network. This is done by measuring the fraction of paths connecting all pairs of nodes and containing the node of interest. Eigenvector centrality is a more sophisticated version of degree centrality where the centrality of a node not only depends on the number of links incident on the node but also the quality of those links. This quality factor is determined by the eigenvectors of the adjacency matrix of the network.

15 Some tools (I) Weka 3: data mining software in Java Apache Mahout: scalable machine learning library Natural language toolkit (NLTK) Gephi: network analysis

16 Some tools (II) igraph: network analysis package Data visualization Hive: distributed data warehouse Pig: analyzing large dataset

17 Recommended papers Big data report: business_technology/ big_data_the_next_frontier_for_innovation MapReduce: research.google.com/en/us/archive/mapreduceosdi04.pdf

18 Recommended papers Machine learning algorithm survey: 498/10Algorithms-08.pdf Community detection in a network survey: Topic modeling: Blei2011.pdf

19 Thank you