Draw the flowchart for arrival and departure event. Compare event-scheduling, process interaction and activity scanning algorithms.

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written 5.6 years ago by

yashbeer ★ 11k

Single server system (SSQ) [Arrival and Departure]

A single server system consists of two entities server and customer (being served or in the queue). Server has only two possible states: busy or idle. Simulation is used to track the simulated time.

If a customer has just completed service, a "departure" event occurred.

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As service of current customer gets over, server may become idle or remain busy depends on state of s/m at that instance of time

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It is impossible for server to be busy if the queue is empty. The arrival event occurs when a customer enters into the system. The simulation proceeds in the following way.

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The customer may find the server idle or busy. The customer's service begins immediately or it enters into the queue which depends on the status of the server.

If the arrival event occurred and server is busy then customer joins the end of a single queue. If the server is idle i.e. queue is empty, the service of arrived customer immediately starts. The server to be idle and non-empty queue is an impossible state of s/m.

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Event list is used to keep track of future times at when arrival and departure events may occur.

Comparison of Algorithms

Parameter	Event Scheduling	Process Interaction	Activity Scanning
a) Main focus	Events and their effect on s/m state	Moving entities (transaction of processes)	Activities (a model and condition)
b) Simulation Time	Depends on future event list in chronological order	Variable time increment	Fixed increment
c) Complexity	Complex due to maintenance of time ordering of events	Complex due to sequence list of events, entities, delay, demand of resources and queuing	It is a simple concept
d) Event Lists	Future event list (FEL)	FEL and current event list (CEL)	No event list is maintained
e) Stopping Event (SE)	Setting specified future time $T_{SE} [0, T_{SE}]$ or no. of events	Termination counter is zero or below	If all activity conditions are not true

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