A Savitzky-Golay filter can be used as alternative to running mean or median filters. It tries to approximate a given signal using a sliding window approach and a low degree polynomial to model data within that window.

# Category: Data Analysis

# Install R from source: a simple way to compile R from source and use it in RStudio or on servers without X

Sometimes we need to use special versions of R (e.g. the latest version of R is not available in the repositories of the machine we need to use). This post describes a simple way of compiling R from sources and using it in RStudio or on servers without X.

# Weka on Android: load precomputed model and predict new samples

Imagine you want to do a machine learning prediction on Android. Usually, neither the storage capabilities (for storing the training data) nor the computational power for training such models is available on mobile devices - assuming that you use a medium or large dataset and thorough evaluation of different model types and model parametrizations with a subsequent model selection. This post demonstrates how to load and use a model file on Android, which was previously trained offline using the Weka framework.

# Weka in Java: Predict new samples using a precomputed and exported model object

Weka allows for exporting/saving computed models into a binary model file (usually having a ".model" file extension). On other machines (that e.g. don't have access to training data or would lack the computational power for training the model themselves), those model files can be loaded and used to predict new samples...

# SVM classification example with performance measures using R caret

This example is a followup of hyperparameter tuning using the e1071 package in R. This time we're using the SVM implementation from the R caret package, a binary class classification problem and some extended features that come in handy for many classification problems. For an easy start with caret take a look at one of … Continue reading SVM classification example with performance measures using R caret

# mctune: multicore hyperparameter tuning in R on the example of SVM car detection

mctune In Machine Learning (ML) tasks finding good hyperparameters for machine learning models is critical (hyperparameter optimization). In R there exist some packages containing routines doing that for you using grid search (constructing and testing all possible parameters as a grid, e.g. in David Meyer's e1071 package). Besides the very good routines already contained in … Continue reading mctune: multicore hyperparameter tuning in R on the example of SVM car detection

# Image classification using SVMs in R

Recently I did some Support Vector Machine (SVM) tests in R (statistical language with functional parts for rapid prototyping and data analysis -- somehow similar to Matlab, but open source ;)) for my current face recognition projects. To get my SVMs up and running in R, using image data as in- and output, I wrote a … Continue reading Image classification using SVMs in R