TABLE 1

Key Aspects of ML Algorithms

AlgorithmTaskSupervision?ModelTypical cost functionComputational burdenAssumptions/comments
Naïve Bayes classificationClassificationSupervisedSeveral (e.g., Gaussian)ProbabilisticLowRelies on naïve probability distribution
Linear regressionRegressionSupervisedHyperplaneMSELow
Support vector machinesClassification or regressionSupervisedHyperplaneClassification rate, MSEModerateHandles complex problems
Random forestClassification or regressionSupervisedTreeClassification rate, MSELow–moderateIs tolerant to overfitting
ANNClassification or regressionSupervised (typical); unsupervised/reinforcement learning (less common)Neurons connected in layersClassification rate, MSEHighIs used for complex problems; may be convolutional or deep
k-means clusteringClusteringUnsupervisedCluster centroidDistance to cluster centerModerate (depends on problem)Identifies centroids and assigns data to nearest centroid
Hierarchical clusteringClusteringUnsupervisedDendrogramDistance between data pointsModerate (depends on problem)Clusters data by identifying data-points that are similar
Principal-component analysisDimensionality reductionUnsupervisedPrincipal componentsModerate (depends on problem)
  • MSE = mean square error.