Blog Archives

Coloring the world – Extracting user specific color palettes from Tableau Workbooks

June 22, 2014
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Coloring the world – Extracting user specific color palettes from Tableau Workbooks

nIf you read some of my last blog post you may notice that R got a new companion called Tableau. Tableau is an easy to use and mighty BI toolbox for visualizing all kinds of data and I suggest everybody to give it a trial. One of the things that I like very much is that it gives...

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“The Winner Takes It All” – Tuning and Validating R Recommendation Models Inside Tableau

May 4, 2014
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“The Winner Takes It All” – Tuning and Validating R Recommendation Models Inside Tableau

Introduction My last blog article shows how to build an interactive recommendation engine in Tableau using a simple model utilizing the cosine similarity measure. While this can be a good way to explore unknown data, it is wise to validate any model before...

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“Show me the way to the next whiskey bar” (The Doors – Alabama Song) – Interactive Location Recommendation using Tableau

February 2, 2014
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“Show me the way to the next whiskey bar” (The Doors – Alabama Song) – Interactive Location Recommendation using Tableau

Since I started using Tableau I’m quite fascinated about the capabilities of this piece of software. Before Christmas I was looking how I could build an interactive visualization that helps me to explore the relationships between different objects in a form that shows which objects are very close to each other according to some similarity measure or vice versa....

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Dream Team – combining Tableau and R

November 3, 2013
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Dream Team – combining Tableau and R

Last quarter was a bit too busy to write some new blog post because of a new job. And changing the job often come along with changing the tools you work with. That was my way to Tableau. Tableau is one of the new stars in the BI/Analytics world and definitely worth a look. The people at Tableau...

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Time Is on My Side – A Small Example for Text Analytics on a Stream

June 23, 2013
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Time Is on My Side – A Small Example for Text Analytics on a Stream

Introduction and Background While my last posting was about recommendation in the context of Location Based Social Networks there are also other interesting topics regarding the analysis of unstructured data. The most established one is probably Text Analytics/Mining focusing on all sorts of text data.For me, coming from spatial analysis, these topic is relatively new but I couldn’t help noticing...

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Venue Recommendation – A Simple Use Case Connecting R and Neo4j

April 7, 2013
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Venue Recommendation – A Simple Use Case Connecting R and Neo4j

Last month I attended the CeBIT trade fair in Hannover. Besides the so called “shareconomy” there was also another main topic across all expedition halls - Big Data. This subject is not completely new and I think that a lot of you also have experiences with some of the tools associated with Big Data. But due to the great...

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The Wisdom of Crowds – Clustering Using Evidence Accumulation Clustering (EAC)

February 24, 2013
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The Wisdom of Crowds – Clustering Using Evidence Accumulation Clustering (EAC)

Today’s blog post is about a problem known by most of the people using cluster algorithms on datasets without given true labels (unsupervised learning). The challenge here is the “freedom of choice” over a broad range of different cluster algorithms and how to determine the right parameter values. The difficulty is the following: Every clustering algorithm and even...

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Predictive Modeling using R and the OpenScoring-Engine – a PMML approach

December 13, 2012
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Predictive Modeling using R and the OpenScoring-Engine – a PMML approach

On November, the 27th, a special post took my interest. Scott Mutchler presented a small framework for predictive analytics based on the PMML (Predictive Model Markup Language) and a Java-based REST-Interface. PMML is a XML based standard for the description and exchange of analytical models. The idea is that every piece of software which supports the corresponding...

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Matching clustering solutions using the ‘Hungarian method’

November 19, 2012
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Matching clustering solutions using the ‘Hungarian method’

Some time ago I stumbled upon a problem connected with the labels of a clustering. The partition an instance belongs to, is mostly labeled through an integer ranging from 1 to K, where k is the number of clusters. The task at that time was to plot a map of the results from the clustering of spatial polygons...

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Benchmarking distance calculation in R

October 18, 2012
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Benchmarking distance calculation in R

A typical step in a lot of data mining methods is the calculation of a distance between entities. For example using the nearest-neighbor method it is crucial to do this calculation very efficiently because it is the most time-consuming step of the procedure. Just imagine you want to compute the Euclidean distance between a constantly changing database...

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