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Hot answers tagged unsupervised-learning

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I disagree with the context that MNIST is the "hello world" of supervised learning. It is definitely, though, the "hello world" of image classification, which is a very specific sub-field of supervised learning. I'd consider the Iris dataset a better candidate for the "hello world" of supervised learning, with other close ...

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Supervised learning The supervised learning (SL) problem is formulated as follows. You are given a dataset $\mathcal{D} = \{(x_i, y_i)_{i=1}^N$, which is assumed to be drawn i.i.d. from an unknown joint probability distribution $p(x, y)$, where $x_i$ represents the $i$th input and $y_i$ is the corresponding label. You choose a loss function $\mathcal{L}: ... 2 Yes, you could use clustering: Encode your features as a feature vector and feed it into a clustering algorithm (see Finding Groups in Data for a comprehensive description of these). You could use agglomerative clustering, which would give you groups of similar items; perhaps different level headings will be clustered together. Alternatively you could try a ... 2 One problem with clustering algorithms is that they will typically find you a solution, ie they will split your data set into clusters, but it will find you a structure even if there isn't one. Your data looks like it could consist of about 5 to 7 clusters, but it could equally well just be 2 or only 1. What you need to do after the clustering is to assess ... 2 There are some unsupervised learning algorithms that can be used for pattern recognition (i.e. the discovery of patterns in data). The most notable one is probably k-means, which is a clustering algorithm. In k-means, you cluster your unlabeled data into groups (or clusters) based on the distance (or similarity) between them. When a new data point arrives, ... 2 In Supervised learning, the goal is to learn a mapping from points in a feature space to labels. So that for any new input data point, we are able to predict its label. whereas in Unsupervised learning data set is composed only of points in a feature space, i.e. there are no labels & here the goal is to learn some inner structure or organization in the ... 2 SOM (Self-Organinizing Map) is a type of artificial neural network (ANN), introduced by the Finnish professor Teuvo Kohonen in the 1980s, that is trained using unsupervised learning to produce a low-dimensional, discretized representation of the input space of the training samples, called a map, and is therefore a method to do dimensionality reduction. SOM ... 2 A typical clustering algorithm is k-means (and not k-NN, i.e. k-nearest neighbours, which is primarily used for classification). There are other clustering algorithms, such as hierarchical clustering algorithms. sklearn provides functions that implement k-means (and an example), hierarchical clustering algorithms, and other clustering algorithms. To assess ... 1 I shall suggest one more popular metric for this. Davies Bouldin Score (https://scikit-learn.org/stable/modules/generated/sklearn.metrics.davies_bouldin_score.html#sklearn.metrics.davies_bouldin_score). You can also take a look at the clustering metrics in scikit documentation (https://scikit-learn.org/stable/modules/classes.html#module-sklearn.metrics). 1 You can compute "Silhouette Coefficient" for your aim. Its values mean: 1: Means clusters are well apart from each other and clearly distinguished. 0: Means clusters are indifferent, or we can say that the distance between clusters is not significant. -1: Means clusters are assigned in the wrong way. Also other measures such as purity and mutual ... 1 How to fix the network above to auto-classify XOR data, in unsupervised manner? This cannot be done, except accidentally. Unsupervised learning cannot replace or emulate supervised learning. As a thought experiment, consider why you would expect the network to discover XOR, when simply considering outputs rounded to binary, you could equally find AND, OR, ... 1 In the paper Generalization in Unsupervised Learning (2015), Abou-Moustafa and Schuurmans develop an approach to assess the generalization of an unsupervised learning algorithm$A$on a given dataset$S$and how to compare the generalization ability of two unsupervised learning algorithms$A_1$and$A_2\$, for the same learning task. They first provide a ...

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Yes you can use KNN algorithm to cluster (well actually its a classification not a clustering if you use KNN) the data. But, first you need to set one feature as a label because KNN is a supervised learning method, it need a labeled data to train the data first. For example you can use Gender as label to classify the data. To determine the quality of the ...

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