(Solved): 1. A hospital ship offers eye operations to patients in third world cities. The surgery on this shi ...

1. A hospital ship offers eye operations to patients in third world cities. The surgery on this ship uses a two stage process. In the first stage patients are anaesthetised in one room; this process takes a time which is exponentially distributed with a mean of 10 minutes. There are three anaesthetists. Patients are then taken on trolleys to the operating theatre where the eye operations are actually performed. The operating theatre has seven surgeons who perform the various surgical procedures in a time which is Erlang-3 distributed with a mean of 20 minutes. The surgeon will then scrub up for the next procedure; the time before the surgeon is again free to operate has an Erlang-5 distribution with a mean of 3 minutes. If no berth in the operating theatre is free after a patient has been anaesthetised the patient can wait on the trolley in the anaesthetic room. There is no space for a queue between the anaesthetic room and the operating theatre. If an anaesthetised patient has to wait, the anaesthetist is blocked and cannot anaesthetise another patient. (a) List all the entities in the system; indicate which entities are permanent and which are temporary. [2] (b) Draw activity cycle diagrams for all entities in the system. Mark the activities on these diagrams, number them, and identify them as either bound or conditional. \( [10] \) (c) Write a one line description of each of the activities which involves an anaesthetist. Write a test-head for each of the conditional activities in this set. [8]