C4.5 Decision Tree Implementation

It’s time to go deeper in decision tree induction. In this post, I’ll give summary on real-world implementation (i.e. the implementation has been used in actual data mining scenario) called C4.5.

C4.5

C4.5 is collection of algorithms for performing classifications in machine learning and data mining. It develops the classification model as a decision tree. C4.5 consists of three groups of algorithm: C4.5, C4.5-no-pruning and C4.5-rules. In this summary, we will focus on the basic C4.5 algorithm

Algorithm

In a nutshell, C4.5 is implemented recursively with this following sequence

  1.     Check if algorithm satisfies termination criteria
  2.     Computer information-theoretic criteria for all attributes
  3.     Choose best attribute according to the information-theoretic criteria
  4.     Create a decision node based on the best attribute in step 3
  5.     Induce (i.e. split) the dataset based on newly created decision node in step 4
  6.     For all sub-dataset in step 5, call C4.5 algorithm to get a sub-tree (recursive call)
  7.     Attach the tree obtained in step 6 to the decision node in step 4
  8.     Return tree

Continue reading C4.5 Decision Tree Implementation

Decision Tree Induction

After learning some basics about Machine Learning (ML), time to get into the details related to my thesis. After discussing with my supervisors, we decided to implement classification algorithm based on decision tree. So, in this post, I would like to give an overview about decision-tree in ML.

An example of decision tree from XKCD
An example of decision tree from XKCD 😉

What is decision-tree?

Decision-tree is the common output of a divide-and-conquer approach in learning from a set of independent instances. A decision tree consists of nodes and branches. Each node consists of questions based on one or several attributes i.e. compares an attribute value with a constant or it could compare more than one attributes using some functions. Learning data set to produce a decision tree is often called tree-induction. Continue reading Decision Tree Induction

Bootstrapping Machine Learning

My thesis will be related to machine learning(ML), therefore, I need to learn the necessary ML knowledge to do the project. In this post, I would like to revisit some concepts and materials that I used to start learning about ML. Feel free to comment and give suggestions!

Machine Learning is not statistics and not data-mining, but it is in between them. ML is more like automated application of statistics to perform data mining tasks i.e. ML develops algorithms for making predictions from data. Note that predictions in this context refers to statistical-prediction.

Not this kind of Machine Learning though :p

Data in ML consists of data instances. The data instances are represented as feature vectors. Continue reading Bootstrapping Machine Learning

Thesis: Pilot

After one and half month starting my master thesis, finally I have chance to start writing about it. And after getting the permission from one of my supervisors, Gianmarco, I can publish this post, yay!

In this pilot post, I would like to give overview of the thesis. In a nutshell, the thesis is about achieving high velocity in big data analytics, by developing distributed streaming machine learning framework. So, without further ado, here is the overview. 😀

Yes, my thesis is related to big data analysis
Yes, my thesis is related to big data analysis

*the above cartoon image is taken from Space & Light’s Flickr

The Overview

Everyone is talking about big data and one of the initial questions surrounding big data is “how to store it?”. Continue reading Thesis: Pilot

Towards High Availability in YARN: Implementations and Experiments

This post is a follow-up post about our project, High Availability in YARN. In the previous post, we have explained the motivation and our proposed solution to solve availability problem in YARN. Now, let’s continue with the implementations and experiments that we have done as proofs of concepts for our proposed solution.

Implementation

As a proof-of-concept of our proposed architecture, we designed and implemented NDB storage module for YARN resource-manager. Due to limited time, recovery failure model was used in our implementation. In this post, we will refer the proof-of-concept of NDB-based-YARN as YARN-NDB.

Continue reading Towards High Availability in YARN: Implementations and Experiments

Towards High Availability in YARN: Motivation and Proposed Solution

Finally, it’s the end of my 3rd semester with EMDC and I would like to share our latest project: High Availability in YARN. This project is collaboration between EMDC and Swedish Institute of Computer Science (SICS). The project members are Arinto (me :p) and Mário. Our project partners are Umit and Strahinja (they worked on node-manager of YARN). And this project is supervised by Jim Dowling and mentored by Vasia Kalavri.

This post explains the motivation behind the project and our proposed solution. The follow-up post explains the implementations and experiments as proofs of concept of our solutions.

Problem statement

YARN solves scalability issues of previous MapReduce framework. It also offers flexibility in executing the computation framework on top of a cluster where YARN is deployed1.  However, it still has one limitation, which is on its availability.

Continue reading Towards High Availability in YARN: Motivation and Proposed Solution

  1. Apache Hadoop YARN Background and Overview []