PPT-Chapter 9 Finding Groups of Data – Clustering with k-means

Chapter 9 Finding Groups of Data Clustering with kmeans Objectives The ways clustering tasks differ from the classification tasks we examined previously How clustering defines a group and how such groups are identified. Margareta Ackerman. Work with . Shai. Ben-David, . Simina. . Branzei. , and David . Loker. . Clustering is one of the most widely used tools for exploratory data analysis.. . Social Sciences. Biology. K. -means. David Kauchak. CS 451 – Fall 2013. Administrative. Final project. Presentations on Friday. 3 minute max. 1-2 PowerPoint slides. E-mail me by 9am on Friday. What problem you tackled and results. Margareta Ackerman. Work with . Shai. Ben-David, . Simina. . Branzei. , and David . Loker. . Clustering is one of the most widely used tools for exploratory data analysis.. . Social Sciences. Biology. Lecture outline. Distance/Similarity between data objects. Data objects as geometric data points. Clustering problems and algorithms . K-means. K-median. K-center. What is clustering?. A . grouping. of data objects such that the objects . Machine . Learning . 10-601. , Fall . 2014. Bhavana. . Dalvi. Mishra. PhD student LTI, CMU. Slides are based . on materials . from . Prof. . Eric Xing, Prof. . . William Cohen and Prof. Andrew Ng. David Kauchak. CS . 158. . – Fall . 2016. Administrative. Final project. Presentations on . Tuesday. 4. . minute max. 2. -. 3. slides. . . E-mail me by . 9am . on . Tuesday. What problem you tackled and results. Fuzzy . k. -means. Self-organizing maps. Evaluation of clustering results. Figures and equations from Data Clustering by . Gan. et al.. Center-based clustering. Have objective functions which define how good a solution is;. issue in . computing a representative simplicial complex. . Mapper does . not place any conditions on the clustering . algorithm. Thus . any domain-specific clustering algorithm can . be used.. We . High Density Clusters June 2017 1 Idea Shift Density-Based Clustering VS Center-Based. 2 Main Objective Objective: find a clustering of tight knit groups in G. 3 Clustering Algorithm : Recursive Algorithm based on Sparse Cuts Produces a set of . nested clusters . organized as a hierarchical tree. Can be visualized as a . dendrogram. A tree-like diagram that records the sequences of merges or splits. Strengths of Hierarchical Clustering. Log. 2. transformation. Row centering and normalization. Filtering. Log. 2. Transformation. Log. 2. -transformation makes sure that the noise is independent of the mean and similar differences have the same meaning along the dynamic range of the values.. Department of Biological Sciences. National University of Singapore. http://. www.cs.ucdavis.edu. /~. koehl. /Teaching/BL5229. koehl@cs.ucdavis.edu. Clustering is a hard problem. Many possibilities; What is best clustering ?. Randomization tests. Cluster Validity . All clustering algorithms provided with a set of points output a clustering. How . to evaluate the “goodness” of the resulting clusters?. Tricky because . What is clustering?. Grouping set of documents into subsets or clusters.. The Goal of clustering algorithm is:. To create clusters that are coherent internally, but clearly different from each other.