6.14 Review of several problems Figure P6.14 shows a transportation network with 10 demand points (towns, centers, etc.)
a. What is the location of an emergency facility that minimizes expected travel time?
b. A regional planning committee wishes to designate "emergency artery" roads so that all the demand points are connected in time of snow. If the criterion is to select the minimum total length (in terms of travel time) of emergency artery roads, what are the corresponding roads?
c. What is the median and the absolute center with respect to the emergency artery roads only?

d. Note that nodes E, G, C, and F are demand points with large demand rate. By inspection, determine the minimum network (subgraph) that connects these points.
e. How will the solution in part (d) change if J is also included in the required subgraph ?
f. Comment on the answers of parts (d) and (e). Is there any special network structure for these subgraphs?
g. Find a "good" traveling salesman tour on this graph. (Your tour need not be optimal and you may use any approach you wish.)
h. What is the length of the optimum Chinese postman tour of this network?