Results and Conclusion
The graph theory and the digraph matrix approach is a method that involves lesser computation when compared with
other decision making models and methods. Also, it is comparatively simple, easy and generic as it can be applied to
a whole lot of situations by only altering the attributes/criteria and choosing suitable alternatives. In the paper, the
need for the setting up of collection centres was realized. This was then translated into the desire to apply a suitable
methodology for taking the decision for the location of the same. For this, it was seen that Graph Theoretic Approach
served the purpose completely by taking important factors into consideration. Thus, the methodology was introduced
and discussed. After this, the numerical expressions and the method to calculate the indexes and comparison were also
discussed. Then this method was illustrated with the example of ABC info systems which makes an attempt to collect
e-waste from the customers and recycle it when the products reach their End of Life (EOL). For this, after talking to
the e-waste manager in Delhi, the various important factors (criteria) as well as locations along with alternatives were
decided. Then, collectively, the matrixes for all the nine locations were made. These, may however vary as different
decision makers may have varied opinions about what is more important ad by what measure. Consequently, the
matrices were solved and the SSI’s (Site Selection Index) for all were calculated. Then, from each state one out of the
three alternatives was chosen to be the best site because of the highest value of the SSI. For Punjab, SSI1>SSI2>SSI3,
hence A1 (Jallandhar) is the best place to set up a site. For Goa, SSI4>SSI5>SSI6, hence B1 (Panaji) would be the
most important place to set up the collection centre. For Rajasthan, SSI8>SSI7>SSI9, hence, it would be best to set
up a collection centre at C2 (Jaipur).