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Meetup 02-2019 Minutes

Self Service Data Preparation und Data Science Peter Jeitschko Peter presented Alteryx, a platform built for Business Analysts to master tasks like data management, data cleaning and modelling. The tool is windows only and will be ported to Linux soon. It can connect to multiple data sources and helps Business Analysts to deploy models in production. Finally, Peter also showed a Demo including data ingestion, an example of the Facebook Face API and some community features.

igraph Applications for Transportation Networks

Materials from Max Leodolters talk in May covering the igraph package. require(igraph) require(data.table) require(ggplot2) Centrality - What is it? Network Centrality gives you an idea of how important a vertex/node and edge/link in your network/graph \(N(V,E)\) respectively \(G(N,L)\) is. Examples: Closeness Betweenness Eigenvalue degree … Some formulas: Closeness Centrality \[ C^{node}(n) = \frac{1}{\sum_{m \in N \setminus \{n\}}d(n,m)} \] Betweenness centrality \[ B^{node}(n) = \sum_{m\neq o \in N\backslash \{n\} } \frac{\sigma_{mo}(n)}{\sigma_{mo}} \] Node-based Closeness for a link \[ \ddot{C}^{link}(l_{n,m}) = \frac{C^{node}(n) + C^{node}(m)}{2} \] Node-based Betweenness for a link \[ \ddot{B}^{link}(l_{n,m}) = \frac{B^{node}(n) + B^{node}(m)}{2} \] Link-based Betweenness for a link \[ B^{link}(l) = \sum_{n \neq m \in N } \frac{\sigma_{nm}(l)}{\sigma_{nm}} \] *\(\sigma\) is the number of traversing OD relations, and \(d(n,m)\) is the distance of the shortest route from \(n\) to \(m\) What to select, \(\ddot{B}^{link}(l_{n,m})\) or \(B^{link}(l)\)?

Meetup 06-2016 Minutes



The last meetup before the summer break concluded the igraph session with a talk by Rainer. Mario summed up his impressions from the R/Finance 2016 conference.

Meetup 05-2016 Minutes



This meetup extensively covered the igraph package with talks by Florian Sobieczky and Max Leodolter.

Meetup 04-2016 Minutes



This meetup included an extensive Text Mining in R session with an Introduction to tm by Ingo Feinerer and a talk about Text Mining with Hadoop by Stefan Theussl.

Wordcloud Wienerwald

**Wordcloud** \
*Ödön von Horvath - Geschichten aus dem Wienerwald*

After a very nice hands-on introduction in yesterday’s Vienna R meetup meeting from Mario Annau, I created an example of textmining ending with a wordcloud. As the blog is called ViennaR, I chose to use a play strongly related to Vienna - Ödön von Horváth - Geschichten aus dem Wienerwald.