ISR10
Scientific Report No. ISR-10 Information Storage and Retrieval
Evaluation of Document Retrieval Systems
chapter
Joseph John Rocchio
Harvard University
Gerard Salton
Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government.
5-26
is the [OCRerr]esired normalize[OCRerr] performance in[OCRerr]ex.
The precision error integral may be evaluate& thra[OCRerr]gh the use
of the unit step function as follows:
p*(x) =[OCRerr]X1[OCRerr]U[OCRerr]l (x-1)
+ ½1(x-2) + + U_1(x-n0)
an~
~ow
p(x) =X1:Ul (x-[OCRerr](1)) + U .i(x[OCRerr](2)) + + U[OCRerr]i(x[OCRerr][OCRerr](n[OCRerr]))
J
b
p
-00
Therefore:
b
½i(x[OCRerr]a) x x
a
= in b - in a
precision error (p*(x) -
1
ri
0
-7
½
i=1
n
0
- 7-/ln[OCRerr]i) in i
I,
i=1 i=1
n
or
0
precision error = in 7[OCRerr][OCRerr]i) in (n0!) (5.21)
i=1
This in[OCRerr]ex may be normalize[OCRerr] to lie in the ran[OCRerr] C - 1 by