Content

Lesson 11/16 | Study Time: 0 Min

MACHINE LEARNING

Machine  learning  is  the  state of the art  approach  to data science.
The main advantage machine learning has over any of the traditional data science techniques
is the fact that at its core resides the algorithm. These are the directions a computer uses to find a model that fits the data as well as possible.
The difference
between machine learning and traditional data  science methods is that we do not give the computer instructions on how to find the sought dependence; it  takes the algorithm and uses its directions to learn on its own how to find that model.
Unlike in traditional data science, human involvement is minimized.  In fact,  machine learning,  especially  deep learning algorithms are so complicated, that humans cannot genuinely understand what is happening “inside” the model.

MACHINE LEARNING THE ALGORITHM
A machine learning algorithm is like a trial-and-error process,  but  the  special  thing  about  it  is  that  each consecutive
trial is at least as good as the previous one.





But bear in mind that in order to learn well, the machine has to go through hundreds of thousands of trial-and- errors,  with  the  frequency  of  errors  decreasing throughout.





Once the training is complete, the machine will be able to  apply  the  complex  computational  model  it  has learned to novel data still to the result of highly reliable predictions.


There  are  three  major  types  of  machine  learning:


                          -supervised

                          -unsupervised, and

                           -reinforcement learning.




SUPERVISED
LEARNING

Supervised learning rests on using labeled data. Imagine having big data consisting of video files and images, labelled as “cats”, “dogs”, & “other”.
The machine gets data that is associated with a correct  answer;  if  the  machine’s  performance does not get that correct answer, an optimization algorithm adjusts the computational
process, and the  computer  does  another  trial. 
Typically,  the machine does this on hundreds of data points at once.

Support vector machines, neural networks, deep learning,  random  forest  models,  and  Bayesian networks are all instances of supervised
learning.

UNSUPERVISED LEARNING
When the data is too big, or the data scientist is pressured for resources to label the data, or they do  not  know  what  the  labels  are  at  all,  data science  resorts  to  using  unsupervised  learning.



This  consists  of  giving  the  machine  unlabeled data and asking it to extract insights from it. This often results in the data being divided in a certain way according to its properties. In other words, it is clustered.



Unsupervised learning is extremely effective for discovering patterns in data, especially things that humans  using  traditional  analysis  techniques would miss.

REINFORCEMENT LEARNING

This
is
a type of machine
learning
where the
focus is  on  performance  (to  walk,  to  see,  to  read), instead  of  accuracy. 

Whenever  the  machine performs better than it has before, it receives a reward,  but  if  it  performs  sub-optimally,  the optimization  algorithms  does  not  adjust  the computation.

This
optimal behavior is learned through interactions with the environment and
observations of how it responds, similar to children exploring the world around
them and learning the actions that help them achieve a goal
.



















Some applications are in robotics, autonomous driving, etc