Building a Python package

Ioannis NasiosPython Leave a Comment

I have been working with Python over the last years, using Python mainly for machine learning projects but I had never built a package. Recently I built my first Python package SolarSystem and published it on github and on Pypi. The idea of SolarSystem, i.e. planets and other celestial objects position estimation as a time function, was old as well …

Transfer learning for image classification with Keras

Ioannis NasiosComputer Vision, Data Science, Deep Learning, Keras Leave a Comment

  Transfer learning from pretrained models can be fast in use and easy to implement, but some technical skills are necessary in order to avoid implementation errors. Here we describe a fast and easy to understand procedure using data from Kaggle’s Dog Breed Identification competition as an example. The same principles can be applied on virtually any image classification problem. …

Graph analysis of Stack Overflow tags with Oracle PGX – Part 2: Incremental Updates

Panagiotis KonstantinidisData Engineering, Oracle NoSQL, Oracle PGX Leave a Comment

This is the second part of our three-part blog post series (see the first part here), which deals with incremental data updates. In our scenario we assume that we acquire small batches of data updates using some kind of web scraping mechanism. We will not deal with the details of that mechanism, as it is beyond the scope of this …

Graph analysis of Stack Overflow tags with Oracle PGX – Part 1: Data Engineering

Panagiotis KonstantinidisBig Data, Data Engineering, Oracle NoSQL, Oracle PGX 1 Comment

Intoduction Oracle Parallel Graph Analytics (PGX) is a toolkit for graph analysis, both for running algorithms such as PageRank and for performing SQL-like pattern-matching against graphs. Extreme performance is offered through algorithm parallelization, and graphs can be loaded from a variety of sources such as flat files, SQL and NoSQL databases etc. So, in order to get a deeper feeling, …

Enabling the Green-Marl compiler for Parallel Graph Analytics in Oracle Big Data Lite VM

Panagiotis KonstantinidisOracle Big Data Spatial & Graph Leave a Comment

Recently, I began working with Parallel Graph Analytics (PGX) on my Oracle Big Data Lite (BDL) VM version 4.7.0.1. I was especially intrigued and curious about the capabilities of a PGX component called Green-Marl (GM), a domain-specific language specially designed for graph data analysis. It was stated to extend PGX’s capabilities and “implement algorithms with no limit”. Especially the last argument …

Streaming data from Raspberry Pi to Oracle NoSQL via Node-RED

Christos - Iraklis TsatsoulisInternet of Things, Node-RED, Oracle NoSQL, Raspberry Pi Leave a Comment

Starting from version 4.2, Oracle NoSQL now offers drivers for Node.js and Python, in addition to the existing ones for Java, C, and C++; this is good news for data science people, like myself, since we are normally not accustomed to code in Java or C/C++. So, I thought to build a short demo project, putting into test both the …

Workaround for disclosed af:query issue on ADF 12.2.1

Michael KoniotakisOracle ADF 1 Comment

While migrating ADF applications from 11 to 12 we stepped on a known bug in ADF 12.2.1 Bug 22469635 : AF:QUERY COMPONENT BUTTONS DON’T WORK WHEN “DISCLOSED” SET TO “FALSE” Since this is not resolved yet we needed a workaround. There were search criteria with disclosed=”false” in pages with rich layout that the user should expand it only if he …

sparklyr: a test drive on YARN

Christos - Iraklis TsatsoulisR, Spark 2 Comments

sparklyr is a new R front-end for Apache Spark, developed by the good people at RStudio. It offers much more functionality compared to the existing SparkR interface by Databricks, allowing both dplyr-based data transformations, as well as access to the machine learning libraries of both Spark and H2O Sparkling Water. Moreover, the latest RStudio IDE v1.0 now offers native support …