Koostööfilterdamissüsteemid

Koostööfilterdamissüsteemid, or collaborative filtering systems, are a class of algorithms used by recommender systems to recommend items to users based on the preferences or tastes of many users. These systems are widely used in various applications, including e-commerce, streaming services, and social media, to provide personalized recommendations.

The core idea behind collaborative filtering is that if a user A has the same opinion as user B on an issue, A is more likely to have B's opinion on a different issue than that which is chosen randomly. There are two main types of collaborative filtering: user-based and item-based.

User-based collaborative filtering recommends items by finding users similar to the target user and suggesting items that those similar users have liked. This approach relies on the assumption that users with similar tastes will have similar preferences.

Item-based collaborative filtering, on the other hand, recommends items by finding items similar to those that the target user has liked in the past. This method is based on the assumption that users will prefer items similar to those they have previously enjoyed.

Collaborative filtering systems can be further enhanced by incorporating additional data, such as user demographics, item attributes, and contextual information. This hybrid approach can improve the accuracy and relevance of recommendations.

One of the challenges in collaborative filtering is the sparsity of user-item interaction data, which can lead to difficulties in finding meaningful similarities between users or items. Techniques such as matrix factorization and dimensionality reduction are often employed to address this issue.

Collaborative filtering systems have gained significant attention due to their ability to provide personalized recommendations and their effectiveness in various domains. However, they also face challenges such as scalability, cold start problems, and the need for continuous updating of user preferences.