Case study: A port now has two ship terminals, it’s predicted that the number of the ships to the port will increase to 11 ships per day after five years. Experience has shown that the ship reaches approximately accord with Poisson distribution. Berth occupancy time for handling services approximately accord with a negative exponential distribution. Question: How much should the port handling capacity and the number of new berths be reached, the system can operate more economically rational after 5 years? (Assuming that under the current handling technical conditions, the handling rate can improve to 8.5 ships per day at most. The average daily cost of handling for each berth is 1500 yuan per berth-day. During the ships in the port, average daily cost is 20000 yuan pership-day)