Category Archives: ETL

Time Series Trend and Seasonality Component Decomposition with STL on Spark

You may be interested in decomposing a time series into level, trend, seasonality and remainder components to gain more insight into your time series. You may also be interested in decomposition to separate out the remainder component for anomaly detection. … Continue reading

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Missing Value Imputation with Restricted Boltzmann Machine Neural Network

Missing value is a common problem in many real world data set. There are various techniques for imputing missing values. We will use a kind of Neural Network called RBM for imputing missing values. Restricted Boltzmann Machine (RBM) are stochastic … Continue reading

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Encoding High Cardinality Categorical Variables with Feature Hashing on Spark

Categorical variables are ubiquitous in data. They pose a serious problem in many Data Science analysis processes. For example, many supervised Machine Learning algorithms work only with numerical data. With high cardinality categorical variables, popular encoding solutions like One Hot … Continue reading

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Plugin Framework Based Data Transformation on Spark

Data transformation is one of the key components in most ETL process. It is well known, that in most data projects, more than 50% of the time in spent in data pre processing. In my earlier blog, a Hadoop based … Continue reading

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Bulk Mutation in an Integration Data Lake with Spark

Data lakes act as repository of data from various sources, possibly of different formats. It can be used to build data warehouse or to perform other data analysis activities. Data lakes are generally built on top of Hadoop Distributed File … Continue reading

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Pluggable Rule Driven Data Validation with Spark

Data validation is an essential component in any ETL data pipeline. As we all know most Data Engineers and Scientist spend most of their time cleaning and preparing their data before they can even get to the core processing of … Continue reading

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Leave One Out Encoding for Categorical Feature Variables on Spark

Categorical feature variables is a thorny issue for many supervised Machine Learning algorithms. Many learning algorithms can not handle categorical feature variables. In this post, we will go over an encoding scheme called Leave One Out Encoding, as implemented with … Continue reading

Posted in Big Data, Data Science, ETL, Spark | Tagged | 2 Comments