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Explore the computational challenges of classifying new items based on their k nearest neighbors, sensitivity to k and distance metric, and the impact of k points on decision-making. Learn about optimizing distance metric, avoiding over-fitting, and managing data efficiently.
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The Idea in a Nutshell • Classify a new item based on the classes of its k nearestneighbors. • Sensitivity to • k • distance metric • how the k points contribute to the decision
Computational Challenges • Distance metric needs to be tuned (e.g., parameter scaling). • Given the neighbors, making a decision is tricky. • (Mixed) optimization. • Over-fitting should be avoided. • Finding the nearest neighbors might be time consuming. • Data management/data decomposition/ parallel processing.
Simple Flexible Incremental Amenable to parallelization. Too simple Sensitive to the distance metric, k, and voting. Classification varies with the order data is provided. Pros Cons