# Hierarchical Clustering with R (feat. D3.js and Shiny)

Agglomerative hierarchical clustering is a simple, intuitive and well-understood method for clustering data points. I used it with good results in a project to estimate the true geographical position of objects based on measured estimates. With this tutorial I would like to describe the basics of this method, how to implement it in R with hclust and some ideas on how to decide where to cut the tree. This was also a great opportunity for composing anohter Shiny/D3.js app (GitHub for the code, shinyapps.io for the app) – something I wanted to do for a while now. At the end of the text I am writing a bit about what I learned in that regard.

# Tool for Visualization of Connections between Agents and Entities in Context of Redtubegate

Early in December 2013 a lawfirm began to send out approximately 10 to 40 thousand cease-and-desist letters on behalf of the rightholder of a bunch of porn flicks for streaming those films on redtube. So far, so good. Now a lot of people didn’t like to receive bills ranging from 250 to more than a thousand Euro for streaming erotica just before christmas especially when being pretty sure that they didn’t even do so. Now given the magnitude of this case a lot of these people turned sour and started to dig a bit deeper. And what was brought to light is a shady network of companies with links where there should be none and a bunch of business partners who as well turned out to have more in common than what was to be seen at first glance.

# Animated scatterplot from two stock quotes charts

Originally I had the idea for this little project (still can’t find a name or description for it) when dealing with the stock quotes correlations. The tool I came up with shows the scatterplot for two stock quotes charts and the respective Pearson correlation coefficient. I wanted to see if one can tell from the scatterplot and the coefficient how two stocks relate to each other. I didn’t take this investigation much further than the visualization and some pondering about patterns shown in the scatterplots.

# Insider deals for DAX companies for the past ten years

Out of pure curiosity I wanted to have a closer look at insider tradings / director’s dealings of people associated with the top 30 corportations in Germany – currently listed in the DAX. By law high-ranking managers of a company and people closely related to them have to report their tradings of the respectives company’s stocks. To make this pile of tradings more easily accessible I wrote a tool using the JavaScript library d3.js that shows the stock quotes on a weekly basis (red bar from lowest quote to highest quote that week) and an orange bar for the weeks where insider tradings were done. When you click on an orange bar then a table below the chart is displayed / updated where the details are listed of the separate deals that were executed.