Chapters of Journeys. Chapters of training courses, subjects, and books. Enroll to chapters and start to earn credits.
Users and Adventurer list. View journeys created by other users and adventurers. Earn credits and scores by participating in chapter activities or by creating journeys and chapters.
Group list. Adventure groups that you can join. To join a group, first enroll to the journey of the group.
Customer questions & answers
Enrolled Journey Details
Enrolled chapters of
My Chapter Details
Available Chapters for
Ensemble Approaches: Boosting
Boosting: Combine weak classifiers to reduce bias.
In the Bias vs. Variance chapter, we could see that by balancing bias and variance, we could reduce error rates of classifier. In this chapter we look at one approach for weak classifiers.
The figure above shown in the previous chapter illustrates that weak classifiers tend to underfit the data resulting in high bias: large difference between predictions and target values.
One approach for reducing bias is to improve weak classifiers by focusing training on certain data points that are hard to predict. This way we can improve individual weak classifiers. In addition, we also give different weights to classifiers: the better they perform, the bigger weightings are given to classifiers. We then combine their results by taking weighted averages of the predictions. This will then remove the effects of the classifiers that underfit.
Figure above shows the training step of boosting. In each step, we identify the data points that were hard to predict and train more often for the data points. We also measure performance of classifiers and use that as weights of the classifiers. Here D1 is the input training dataset. Subsequent datasets D2,..,Dn-1 are datasets adjusted to focus on the data points that are difficult to predict. M1,...,Mn are the classification models built in each step.
The next step is combining the prediction results by taking weighted vote.
Please enter your email address that was used to register for the account. An email will be sent to the address with a verification code for you to change your password.
Please enter the verification code sent to your phone.
Account List. Track account activities.
Reward accounts will be created if earn reward points. Earn points by playing the learning games and KOPO apps.
Earn credits by participating in chapter activities.
Select Quiz Type To Play