Questions and Answers
What is the main idea behind Collaborative Filtering?
Item-based Recommendation recommends items that are similar to the ones a user has already liked or purchased.
True
What is the purpose of a KNN classifier in a Recommender System?
To find similar users or items
One-hot encoding is used to convert _______________________ data into a numerical representation.
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What is the harmonic mean of precision and recall?
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Cosine similarity measures the linear correlation between two vectors.
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What is the purpose of Evaluation Metrics in a Recommender System?
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Which type of Collaborative Filtering recommends items to a user based on the preferences of similar users?
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Match the following Evaluation Metrics with their descriptions:
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What is the purpose of a Similarity Metric in a Recommender System?
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Study Notes
K-Nearest Neighbors (KNN) Classifier in Recommender Systems
Collaborative Filtering
- A method used to build recommender systems
- Based on the idea that users with similar preferences will like similar items
- Two types: User-based and Item-based
User-based Recommendation
- Recommends items to a user based on the preferences of similar users
- Finds the k most similar users to the target user
- Recommends items that the similar users have liked or purchased
- Uses a KNN classifier to find similar users
Item-based Recommendation
- Recommends items that are similar to the ones a user has already liked or purchased
- Finds the k most similar items to the target item
- Recommends these items to the user
- Uses a KNN classifier to find similar items
Evaluation Metrics
- Used to measure the performance of a recommender system
- Examples:
- Precision: measures the number of relevant items in the top-N recommended items
- Recall: measures the number of relevant items recommended out of all relevant items
- F1-score: harmonic mean of precision and recall
- Mean Average Precision (MAP): measures the average precision of the top-N recommended items
Similarity Metric
- Used to measure the similarity between users or items
- Examples:
- Cosine similarity: measures the cosine of the angle between two vectors
- Jaccard similarity: measures the similarity between two sets
- Pearson correlation: measures the linear correlation between two vectors
One-hot Encoding
- A method used to convert categorical data into a numerical representation
- Each category is represented as a binary vector (0 or 1) indicating the presence or absence of the category
- Used to convert user or item features into a numerical format that can be used by the KNN classifier
Collaborative Filtering in Recommender Systems
- Collaborative Filtering is a method used to build recommender systems
- It's based on the idea that users with similar preferences will like similar items
- There are two types of Collaborative Filtering: User-based and Item-based
User-based Recommendation
- Recommends items to a user based on the preferences of similar users
- Finds the k most similar users to the target user using a KNN classifier
- Recommends items that the similar users have liked or purchased
Item-based Recommendation
- Recommends items that are similar to the ones a user has already liked or purchased
- Finds the k most similar items to the target item using a KNN classifier
- Recommends these items to the user
Evaluation Metrics for Recommender Systems
- Evaluation Metrics are used to measure the performance of a recommender system
- Examples of Evaluation Metrics include:
- Precision: measures the number of relevant items in the top-N recommended items
- Recall: measures the number of relevant items recommended out of all relevant items
- F1-score: harmonic mean of precision and recall
- Mean Average Precision (MAP): measures the average precision of the top-N recommended items
Similarity Metrics in KNN Classifier
- Similarity Metrics are used to measure the similarity between users or items
- Examples of Similarity Metrics include:
- Cosine similarity: measures the cosine of the angle between two vectors
- Jaccard similarity: measures the similarity between two sets
- Pearson correlation: measures the linear correlation between two vectors
One-hot Encoding in KNN Classifier
- One-hot Encoding is a method used to convert categorical data into a numerical representation
- Each category is represented as a binary vector (0 or 1) indicating the presence or absence of the category
- Used to convert user or item features into a numerical format that can be used by the KNN classifier
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Description
Learn about the K-Nearest Neighbors (KNN) classifier in recommender systems, including user-based and item-based collaborative filtering methods.
