Read the 1986 article footnoted in Sec. 2.1 that describes the third case study presented in Sec. 3.5: “Planning Supply, Distribution, and Marketing at Citgo Petroleum Corporation.”

(a) What happened during the years preceding this OR study that made it vastly more important to control the amount of capital tied up in inventory?

(b) What geographical area is spanned by Citgo’s distribution network of pipelines, tankers, and barges? Where do they market their products?

(c) What time periods are included in the model?

(d) Which computer did Citgo use to solve the model? What were typical run times?

(e) Who are the four types of model users? How does each one use the model?

(f) List the major types of reports generated by the SDM system.

(g) What were the major implementation challenges for this study?

(h) List the direct and indirect benefits that were realized from this study.