Understanding unsupervised machine learning in simpler terms
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unsupervised machine learning |
Earlier in our article series on AI, we talked about supervised machine learning. In this topic we're going to talk about unsupervised machine learning.
Now, unsupervised machine learning is a powerful approach that operates on unlabeled data to uncover hidden patterns, structures, or relationships without any explicit guidance. So we're going to use this topic to explore the principles of unsupervised learning, the role of clustering in this context, comparisons between labeled and unlabeled data, common use cases, and potential disadvantages of unsupervised learning.
How unsupervised learning works:
Now, unsupervised machine learning algorithms analyze labeled data to reveal any sort of underlying patterns, structures, or groupings without any explicit supervision. Unsupervised learning algorithms work with data that lacks any explicit labels or annotations, relying solely on the inherent structure of the data. And these algorithms identify patterns, trends, or regularities within the data, providing insights into its underlying characteristics. And unsupervised learning methods group or cluster data points based on similarities or relationships, organizing data into meaningful clusters or categories.
And the example that I often use is a parking garage full of vehicles. If we wanted to cluster it into three distinct groups, we would see cars, trucks, and motorcycles. Now, clustering is a fundamental technique in unsupervised learning for partitioning data into logical groupings or clusters based on similarity.
Clustering algorithms, organizes data points into coherent groups or clusters based on their shared characteristics or proximity in feature space. And cluster analysis explores the structure of data by identifying clusters, assessing their properties, and interpreting the meaning of each cluster.
Labeled and unlabeled data:
Now, labeled data consists of input features along with the corresponding target labels or annotations, providing supervision for model training. Labeled data instances are tagged or annotated with known output labels, facilitating supervised learning tasks like classification or regression. And labeled data may actually contain multiple labels or annotations for each data instance, enabling more complex learning scenarios such as multi-label classification. So in this particular scenario, we might have a single data instance that represents a dog and an animal.
And labeled data annotations provide informative labels that capture relevant information about the data, enhancing model interpretability and performance. But acquiring labeled data can be costly and time consuming, especially for tasks requiring large volumes of annotated data. This can be quite expensive. And labeled data is primarily utilized in supervised learning tasks, where models learn to predict output labels based on input features, and we already know what the output should be. And labeled data can also be leveraged in semi-supervised learning settings, where a combination of labeled and unlabeled data is used for model training.
Okay, so that's labeled data. But what about unlabeled data? Well, unlabeled data lacks any explicit annotations, tags, or labels, making it suitable for unsupervised learning tasks. Unlabeled data instances simply do not have associated tags or annotations, requiring unsupervised learning algorithms to infer structures or patterns directly from the data itself. And unlabeled data is primarily utilized in unsupervised learning tasks, where models explore the inherent structure of the data without any explicit guidance. And unsupervised learning finds applications in various domains for tasks like data exploration, anomaly detection, association mining, and latent variable modeling.
Some common applications of unsupervised learning models
Unsupervised learning algorithms are used to group similar data points together, enabling a more exploratory analysis and pattern recognition. You have a dataset you don't quite know what it's telling you, so you can ask the model to tell you what the groupings are, and from that you can learn about your data.
And unsupervised learning techniques detect unusual or anomalous patterns in data that deviate from normal behavior, aiding in fraud detection or fault diagnosis. So the model can determine what normal looks like, and then when a new data point comes in, that doesn’t seem to match any of the groupings or clusters that you have, it's an anomaly.
Also, unsupervised learning algorithms can identify frequent patterns or associations among items in transactional data, revealing hidden relationships or dependencies. And once again, this can help with things like fraud. And unsupervised learning models can infer latent variables or hidden factors that explain some observed data patterns, enabling dimensionality reduction and generative modeling.
And finally, despite its versatility, unsupervised learning does have certain limitations and challenges. It's not all sunshine and rainbows. Unsupervised learning models may exhibit lower accuracy compared to supervised learning methods, because they rely solely on data patterns without any explicit target labels, for guidance. And clusters that are identified by unsupervised learning algorithms may not always correspond to meaningful or interpretable classes, leading to challenges in cluster interpretation and validation.
And lastly, interpreting the meaning of identified clusters or patterns in unsupervised learning can be subjective and context dependent, requiring domain expertise and additional validation.
Conclusion:
Unsupervised machine learning is very helpful in discovering hidden patterns within the given data but at the same time it may require careful interpretation as well. While it is very powerful in some tasks like fraud detection or market segmentation but it lacks the precision of supervised learning model as it doesn't have labeled data for training like supervised learning models.
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