a) When a ship arrives at a harbor, it is docking at one of six berths. If all six berths are occupied, the ship leaves the harbor immediately. After docking at a berth, the ship waits for the unloading service of a single crane. The crane unloads the ships in a First-In-First-Out discipline. After unloading, the ship leaves the harbor immediately. Define the system state at time t as [U(t),C(t)], where U(t)= number of ships waiting to be unloaded or being unloaded C(t)= number of busy cranes ( 0 or 1 ) Let [u,c] be the current state of the system. Define events and write the corresponding state transitions. After unloading, suppose that some ships stay in their berths for refuelling by one of the two fillers before leaving, while the others leave immediately. The fillers refuel the ships in a First-In-First-Out discipline. Ships do not require the use of crane for refuelling. Define the system state at time t as [U(t),C(t),R(t),F(t)], where U(t)= number of ships waiting to be unloaded or being unloaded C(t)= number of busy cranes ( 0 or 1 ) R(t)= number of ships waiting to be refueled or being refueled F(t)= number of busy fillers (0,1, or 2) Let [u,c,r,f] be the current state of the system. Define events and write the corresponding state transitions. a) When a ship arrives at a harbor, it is docking at one of six berths. If all six berths are occupied, the ship leaves the harbor immediately. After docking at a berth, the ship waits for the unloading service of a single crane. The crane unloads the ships in a First-In-First-Out discipline. After unloading, the ship leaves the harbor immediately. Define the system state at time t as [U(t),C(t)], where U(t)= number of ships waiting to be unloaded or being unloaded C(t)= number of busy cranes ( 0 or 1 ) Let [u,c] be the current state of the system. Define events and write the corresponding state transitions. After unloading, suppose that some ships stay in their berths for refuelling by one of the two fillers before leaving, while the others leave immediately. The fillers refuel the ships in a First-In-First-Out discipline. Ships do not require the use of crane for refuelling. Define the system state at time t as [U(t),C(t),R(t),F(t)], where U(t)= number of ships waiting to be unloaded or being unloaded C(t)= number of busy cranes ( 0 or 1 ) R(t)= number of ships waiting to be refueled or being refueled F(t)= number of busy fillers (0,1, or 2) Let [u,c,r,f] be the current state of the system. Define events and write the corresponding state transitions