Gegevensset met handgeschreven cijfers

De gegevensset met handgeschreven cijfers heeft ongeveer 160 records voor elk cijfer van 0 tot en met 9. Elk record bestaat uit 256 kolommen met waarden 0 of 1 en stelt een afbeelding voor van 16x16 pixels.

Later in de cursus gebruik je deze data om met flexmix de clusters te vinden die de cijfers verklaren. Nu is het doel om vertrouwd te raken met gegevenssets die je kunt modelleren met mengmodellen op basis van de Bernoulli-verdeling.

Het object data bevat de observaties van slechts twee cijfers uit de oorspronkelijke gegevensset.

Deze oefening maakt deel uit van de cursus

Mixture Models in R

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Oefeninstructies

Gebruik dim() om de afmetingen van het data frame te controleren.
Gebruik glimpse() om de data te bekijken. Dit is een handige functie om elke kolom te inspecteren, zeker als het er veel zijn.
Gebruik de functie show_digit() om de rijen 50 en 100 om te zetten naar een afbeelding.

Praktische interactieve oefening

Probeer deze oefening eens door deze voorbeeldcode in te vullen.

# Dimension
dim(___)

# Apply glimpse to the data
___(data)

# Digit in row 50
show_digit(data[___,])

# Digit in row 100
show_digit(data[___,])

Code bewerken en uitvoeren

Deze oefening maakt deel uit van de cursus

Mixture Models in R

SkillTag.level.intermediateSkillTag.label

4.8+

Begin de cursus gratis

In this chapter, you will be introduced to fundamental concepts in model-based clustering and how this approach differs from other clustering techniques. You will learn the generating process of Gaussian Mixture Models as well as how to visualize the clusters.

Exercise 1: Introduction to model-based clustering Exercise 2: Clustering approaches Exercise 3: Explore gender data Exercise 4: Gaussian distribution Exercise 5: Sampling a Gaussian distribution Exercise 6: (not so good) Estimations of the mean and sd Exercise 7: Gaussian mixture models (GMM)Exercise 8: Simulate a mixture of two Gaussian distributions Exercise 9: Plot histogram of Gaussian Mixture Exercise 10: Mixture of three Gaussian distributions

In this chapter, you will be introduced to the main structure of Mixture Models, how to address different data with this approach and how to estimate the parameters involved. To accomplish the estimation, you will learn an iterative method called Expectation-Maximization algorithm.

Exercise 1: Structuur van mengmodellen Exercise 2: Welke kansverdeling?Exercise 3: Gegevensset met handgeschreven cijfers

Huidige oefening

Exercise 4: Schatting van parameters Exercise 5: Schatting gegeven de waarschijnlijkheden Exercise 6: De kansen berekenen Exercise 7: EM-algoritme Exercise 8: Expectation-functie Exercise 9: Maximization-functie Exercise 10: Pas de twee stappen toe Exercise 11: Plot de geschatte clusters

This chapter shows how to fit Gaussian Mixture Models in 1 and 2 dimensions with `flexmix` package. The data used is formed by 10.000 observations of people with their weight, height, body mass index and informed gender.

Exercise 1: Univariate Gaussian Mixture Models Exercise 2: Number of clusters Exercise 3: Number of parameters Exercise 4: Univariate Gaussian Mixture Models with flexmix Exercise 5: Univariate case with flexmix Exercise 6: Extracting Parameters for Univariate Case Exercise 7: Visualizing Univariate Gaussian Mixture Model Exercise 8: Compare the results Exercise 9: Bivariate Gaussian Mixture Models Exercise 10: Cross-term from covariance matrix Exercise 11: Parameters in the bivariate case Exercise 12: Bivariate Gaussian Mixture Models with flexmix Exercise 13: Fit the model with cross-terms Exercise 14: Get the components Exercise 15: Create the ellipses Exercise 16: Visualize the clusters

In this module, you will learn how Mixture Models extends to consider probability distributions different from the Gaussian and how these models are fitted with `flexmix`. The datasets used are handwritten digits images and the number of crimes in Chicago city. For the first dataset you will find clusters that summarize the handwritten digits and for the second dataset, you will find clusters of communities where is more or less dangerous to live in.

Exercise 1: Bernoulli Mixture Models Exercise 2: Binary images Exercise 3: How many values?Exercise 4: Bernoulli Mixture Models with flexmix Exercise 5: Handwritten digits with `flexmix`Exercise 6: Poisson Mixture Models Exercise 7: Discover the lambda Exercise 8: Sample from Poisson distribution Exercise 9: Poisson Mixture Models with flexmix Exercise 10: Crimes data with `flexmix`