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<title>Measures</title>
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<h1>Relatedness Measures</h1>
<h2>Lesk </h2>
<p>The Lesk measure works by finding overlaps in the extended definitions
of the two concepts. The relatedness score is the sum of the squares of
the overlap lengths. For example, a single word overlap results in a
score of 1. Two single word overlaps results in a score of 2. A two
word overlap (i.e., two consecutive words) results in a score of 4. A
three word overlap results in a score of 9.
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<h2>Vector</h2>
<p>The vector measure works by forming second-order
co-occurrence vectors from the UMLS extended definitions of concepts.
The relatedness of two concepts is determined as the cosine of the
angle between their vectors.
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