Instance-based learning: Difference between revisions

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Examples of instance-based learning algorithm are the [[k-nearest neighbors algorithm|''k''-nearest neighbors algorithm]], [[kernel method|kernel machines]] and [[Radial basis function network|RBF networks]].<ref>{{cite book |author=Tom Mitchell |title=Machine Learning |year=1997 |publisher=McGraw-Hill}}</ref>{{rp|ch. 8}} These store (a subset of) their training set; when predicting a value/class for a new instance, they compute distances or similarities between this instance and the training instances to make a decision.

To battle the memory complexity of storing all training instances, as well as the risk of [[overfitting]] to noise in the training set, ''instance reduction'' algorithms have been proposed.<ref>{{cite journal |title=Reduction techniques for instance-based learning algorithms |author1=D. Randall Wilson |author2=Tony R. Martinez |journal=[[Machine Learning (journal)|Machine Learning]] |publisher=Kluwer |year=2000}}</ref>

Gagliardi<ref name=Gagliardi2011>{{cite journal|last=Gagliardi|first=F|title=Instance-based classifiers applied to medical databases: Diagnosis and knowledge extraction|journal=Artificial Intelligence in Medicine|year=2011|volume=52|issue=3|pages=123–139|doi=10.1016/j.artmed.2011.04.002|url=https://dx.doi.org/10.1016/j.artmed.2011.04.002}}</ref> applies this family of classifiers in medical field as second-opinion [[Clinical decision support system|diagnostic tools]] and as tools for the knowledge extraction phase in the process of [[knowledge discovery in databases]].

One of these classifiers (called ''Prototype exemplar learning classifier'' ([[PEL-C]]) is able to extract a mixture of abstracted prototypical cases (that are [[syndrome]]s) and selected atypical clinical cases.