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Questions tagged [unsupervised-learning]

Finding hidden (statistical) structure in unlabelled data, including clustering and feature extraction for dimensionality reduction.

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Can Agglomerative Clustering (Heirarchical) form non-convex clusters?

I want to know whether Agglomerative Hierarchical clustering draws non-convex cluster boundaries. From sklearn's comparing diff clustering algo experiment it seems like Agglomerative clustering can ...
11 views

Algorithms or techniques for pattern recognition [on hold]

I am looking for algorithms or techniques that could be used for pattern recognition/extraction in data. Preferably I would like to know if there are any algorithm implementations in Python that I ...
30 views

In cluster analysis, is it better to normalize the data or standardize it?

In cluster analysis, is it better to normalize to $[0, 1]$ (i.e., $\frac{x-\min(x)}{\max(x)-\min(x)}$) the data or standardize via z-score (i.e., $\frac{x-\bar{x}}{s_x}$) it? I know normalization ...
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gensim LdaModel - How to reduce the number of words in each topic?

I'm trying to get more sparse topics (Less overlaps between different topics). https://radimrehurek.com/gensim/models/ldamodel.html I know it should be determined by the alpha parameter. I've ...
20 views

LDA: weight distributions of inferred documents

I have trained a two-topic Latent Dirichlet Allocation (LDA) model on a corpus and I am now inferring on a test corpus (the nature of the corpus is irrelevant). During inference, for each new document ...
36 views

Unsupervised classification of images

Assuming I have a dataset of images from two similar classes, for example let's say 95% Labradors and 5% of Chihuahuas and I want to make a classifier. The point is that I need to find the anomalies (...
48 views

Recognizing whether a written and spoken number is the same

For our ML assignment we have three datasets. The challenge is about checking whether a written and spoken number refer to the same number. We're using the MNIST dataset with handwritten numbers, and ...
32 views

How to measure correlation between two groups of variables?

I have a data set that contain 75 variables of football players . These 75 variables basically measures two different types of information. 30 of those variables related to bio metric information ...
12 views

Metric learning with respect to an outcome

Suppose I have $n$ datapoints in $p$-dimensional space, and the $p$ variables are highly heterogenous. That is, there is no natural way to combine them. Some are ordinal, some one-hot, some continuous,...
25 views

Looking for ways to transform time-series data recorded from object movement into equation describing the movement direction of the object

Looking for some time-series data transformation advice! I want to know what's the best way to transform data of 9-tuples time series data of IMU (Inertia Measurement Unit) sensor, recorded from a ...
448 views

Deep learning models for unsupervised semantic segmentation

I am working on semantic segmentation for satellite images using keras and python. It is my understanding that popular models like U-Net require mask images (labels). Are there any unsupervised deep ...
9 views

Is there a representer theorem for unsupervised learning (to justify kernel density estimation)?

In supervised learning, we get a representer theorem by considering regularized losses of the following form: In Kernel Density Estimation, we simply directly assume densities of the form Could this ...
18 views

Predicting user behaviour based on transactional data - flagging “risky” behaviour

Firstly, I'm not sure if this is the right instance of StackOverflow to post on so feel free to ask me to put it elsewhere. I am exploring the concepts of clustering and "unsupervised" learning for ...
31 views

R - high dimension data using k means clustering [closed]

The dataset is 1000(observations) x 700(variables), After using pca to do dimension reduction, PC150 explained 85% Variance, so I use this (1000 x 150) data to do k means clustering. This code was ...