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Information and Knowledge Management using ArcGIS ModelBuilder

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Panagiotis Manolitzas et al.<br />

Satisfaction function <strong>and</strong> error variables for the j-th customer<br />

*<br />

*<br />

It should be noted that Y <strong>and</strong> X i are monotonic functions normalised between 0 <strong>and</strong> 100 (see 0).<br />

Also, in order to reduce the number of the mathematical constraints the following transformation<br />

equations are used:<br />

⎪⎧<br />

z<br />

⎨<br />

⎪⎩ w<br />

m<br />

ik<br />

= y<br />

m+<br />

1<br />

= b x<br />

− y<br />

* k+<br />

1<br />

i i<br />

m<br />

− b x<br />

* k<br />

i i<br />

for<br />

for<br />

m = 1, 2, ..., α −1<br />

k = 1, 2, ..., α −1<br />

<strong>and</strong><br />

i<br />

i = 1, 2, ..., n<br />

According to the aforementioned definitions <strong>and</strong> the assumptions, the basic estimation model can be<br />

written in a linear program formulation, as it follows:<br />

M<br />

⎧<br />

+ -<br />

⎪[<br />

min]<br />

F = ∑σ<br />

j + σ j<br />

j=<br />

1<br />

⎪<br />

⎪under<br />

the constraint s<br />

⎪ j<br />

j<br />

n xi<br />

−1<br />

y −1<br />

⎪<br />

+ -<br />

⎪∑∑wik<br />

− ∑zm−σj+<br />

σ j = 0 for j = 1, 2, ..., M<br />

i=<br />

1 k = 1 m=<br />

1<br />

⎪<br />

α −1<br />

⎪<br />

⎨∑<br />

zm<br />

= 100<br />

⎪m=<br />

1<br />

⎪ n αi<br />

−1<br />

⎪∑∑wik<br />

= 100<br />

⎪ i= 1 k=<br />

1<br />

⎪z<br />

m ≥ 0,<br />

wik<br />

≥ 0 ∀ m, i <strong>and</strong> k<br />

⎪<br />

+ -<br />

⎪σ<br />

j ≥ 0,<br />

σ j ≥ 0 for j = 1, 2, ..., M<br />

⎪<br />

⎩<br />

where M is the number of customers, n is the number of criteria, <strong>and</strong><br />

which variables Xi <strong>and</strong> Y are estimated.<br />

, are the j-th level on<br />

The preference disaggregation methodology consists also of a post optimality analysis stage in order<br />

to face the problem of model stability. The final solution is obtained by exploring the polyhedron of<br />

near optimal solutions, which is generated by the constraints of the above linear program. This<br />

solution is calculated by n linear programs (equal to the number of criteria) of the following form:<br />

⎧<br />

⎪[<br />

] ′ = ∑<br />

⎪<br />

⎨<br />

⎪<br />

≤ +<br />

⎪<br />

⎪⎩<br />

− αi<br />

1<br />

max F wik<br />

for i = 1, 2, ..., n<br />

k=<br />

1<br />

under the constraint s<br />

*<br />

F F ε<br />

all the constraints<br />

of LP (3)<br />

where ε is a small percentage of F*. The average of the solutions given by the n LPs (4) may be taken<br />

as the final solution. In case of non-stability this average solution is less representative.<br />

The assessment of a performance norm may be very useful in customer satisfaction analysis. The<br />

average global <strong>and</strong> partial satisfaction indices are used for this purpose <strong>and</strong> can be assessed<br />

according to the following equations:<br />

S =<br />

α<br />

∑<br />

m=<br />

1<br />

p<br />

m<br />

y<br />

* m<br />

<strong>and</strong> s =<br />

i<br />

α<br />

i<br />

∑<br />

k=<br />

1<br />

p<br />

x<br />

k * k<br />

i i<br />

339<br />

* j<br />

xi y j *<br />

(2)<br />

(3)<br />

(4)<br />

(5)

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