## Ripple support and resistance levels

One of the key topics in the field of technical analysis are support and resistance levels of securities. These are price ranges where the price, when rising from below has a higher likelihood to stop rising, fall back or consolidate in this range, which in this case is called a resistance level for security.

When such level is encountered from above, i.e. when the price is falling, then it can serve as a support level for the price. Which means that there is a higher likelihood that the price will stop falling, will bounce back again and start rising. Or that it will consolidate in this range for a while.

Support and resistance levels often occur at some major turning points where the price has a nice integer value, e.g. Ripple at 1 or Bitcoin at 50,000 USD. This is because the simple prices are often easier spotted as major turning points by traders and investors. Often when people set their stop losses they select as the stop losses the prices which are simple, like Ripple at 1. This then often leads to e.g. Ripple support and resistance levels being at 1.

One way to approach determining support and resistance levels is to use price and trading volume for that. One would assume that the intensity of given support and resistance levels is the more stronger, the longer the price is in a given price range and the greater is the trading volume realized in this range.

Here is an example of Ripple support and resistance levels computed in this way: One can see that indeed the levels are the more intensive in those price ranges where the price has consolidated for longer times.

## Ensembling methods – Bagging, boosting, stacking and blending, application to AI Content Writing

It involves combining several base machine learning models predictions to produce a final outcome.

The ensembling method can have a better accuracy than all of the base models that are part of the ensembler. This happens when the base classifiers are sufficiently diverse and distinctive.

We will try to illustrate why ensembling methods has such good performance with a help of an example.

Let us say that we have 4 machine learning models that produce classifications for three classes. The result of each base classifier will thus be e.g. 100 which would denote presence of class A (1) and absence of classses B (0) and C (0).

Now let us take some input data Y for which we know that the ground truth result is 110.

If we input these data to our ML classifiers we get the following results:

100 (“error”)

110

010 (“error”)

110

However if we run the machine learning model results through ensembling model that uses majority voting, the result will be correct: 110. Despite two errors.

This example shows why combining machine learning models may lead to better results than the base models.

It also helps explain why there is some truth to the wisdom of crowds.

## Ensemble methods

There are several different types of ensembling methods:

• averaging
• bagging
• boosting
• stacking
• blending

#### Averaging

In averaging ensemble method we simply average the predictions of the individual base models.

#### Bagging

The bagging works by taking sampling from the train data set with replacement. Note that in such sampling we may obtain train data sets where the same instances may be present more than time. Once we have the sampled train data sets we train base model on these data sets, obtaining several base models.

If you ask yourself about the origin of the name, it comes by taking characters from the Bootstrapping name. Bagging was introduced by L. Breiman in 1994.

A well known example of bagging are random forests which are just decision trees trained on different samples from train data sets.

Where does bagging help us?

One benefit of bagging is that it decreases the variance of the machine learning model. We all know that all machine learning models suffer from the bias variance trade-off. Bias tells us something about how appropriate is the model for the problem and data set. Variance is the sensitivity of machine learning model to the training data set. Machine learning model with high variance will change greatly if we replace train data set with other instances.

#### Boosting

What about the bias? Well, we can reduce it by using the boosting approach.

In this case we train our base models sequentially. We train the first base model on our data and then reweight instances for which we got poor predictions. Then we train the next base model on this modified data and repeating these steps. The main idea is that the next base model tries to perform well on instances for which there was poor performance by previous base models.

Many boosting algorithms have been developed over the years, e.g. AdaBoost, Gradient boosting and XGBoost.

#### Stacking

Finally, let us consider stacking ensembling method. In stacking we have base models and additional meta model which trains on the out of fold predictions of the base models.

We could e.g. build the following base models:

• logistic regression
• linear regression (lasso, ridge)
• decision trees
• random forests
• support vector machine
• xgboost
• lightbm
• lstm deep neural net
• cnn neural net

Diagram of base models and meta model for stacking: For meta model we can use logistic regression, lasso regression or XGBoost.

Stacking is trained in two major steps:

• train the base models with k-fold validation, set aside the out of fold predictions of the base models
• train the meta model on these out of fold prediction

#### Blending

Blending is slightly different to stacking.

Blending uses the held out validation set instead of out fold predictions, typically 10% of instances are used for this purpose.

### AI Content Writing

In the second part of our article we will discuss recent advances in the field of AI Content Writing. In recent years there has been a lot of great steps in the natural language processing. In computer vision, a big step was the Imagenet competition and the big improvements made as part of it, e.g. AlexNet, Resnet, VGG and other great models which significantly improved performance over prior best results.

In natural language processing consulting we judge that a similar moment was achieved with great improvements in main language tasks with BERT or Bidirectional Encoder Representations from Transformers.