Describe a small system that would be suitable to be modelled as a discrete-even
ID: 3879118 • Letter: D
Question
Describe a small system that would be suitable to be modelled as a discrete-event system. State the purpose of the system, list the plant components, their states, and what events the system would contain. State several control specifications (ie. the temperature must not rise above 100’C) for the system. For each plant component, you should state its initial state (state it is in at startup), list all states it can be in, and list all of its events that allow you to move between states. Remember, states are nouns, and events are verbs (actions).
Note:do not try to represent the system as automata. Just use word descriptions
Explanation / Answer
Let us first define what a Discrete-Event System is:-
A discrete-event simulation (DES) models the operation of a system as a discrete sequence of events in time. Each event occurs at a particular instant in time and marks a change of state in the system. Between consecutive events, no change in the system is assumed to occur; thus the simulation can directly jump in time from one event to the next.
So let me explain this with the help of an example:-
Customers Visiting a Bank for their purpose.
Purpose of the System:- A bank which a long queue of Customers waiting for their chance to get to a counter for various services provided by the ank ie. Withdrawl, deposit, query, exchange currency etc.
System Components are:- Customers, Tellers and Operations
The system events are Customer-Arrival (The Customer enters into the bank), Operations Performed (Bank-related opeartions performed by the Customers) , Bank-Tellers-Work (who assists the Customers), Customer-Departure (Once done with the activities, the customers leave the bank).
The system states, which are changed by these events, are CUSTOMER_QUEUE(an integer from 0 to n) and TELLER_STATUS (busy or Free) and OPERATION_STATUS (Started, In-Progress or Completed , Rejected)
Control Specifications:- Queue of customers should be less than 100. Each Customer can request 3 operations to be performed in a day. The Amount of withdrawl limit is 10000 dollars per day. All Customers must leave by 5PM.
For Customers:-
Initial State:- CUSTOMER_QUEUE(5), meaning the Customer is standing at 5th position in the queue waiting for his turn.
List of states and events:- Customer enters into the bank -> CUSTOMER_QUEUE (Waiting) meaning Customer joins the Queue for his turn to come -> Already, the TELLER_STATUS (Busy), meaning the Teller is busy handling other Customers -> So, the Customer needs to wait, CUSTOMER_QUEUE (Waiting) -> Now the Teller is Free, TELLER_STATUS (Free) -> Bank-Tellers-Work (After becoming Free, he asks Customer about the query) -> Operations Performed (Withdrawl) meaning as per the Customer's Requests, the TEller performs the requested operation -> OPERATION_STATUS (Successful), after the operation is successful, Teller updates the Customer -> Customer-Departure (Leaves the Bank, after having completed his work).
For Tellers:-
Initial State:- TELLER_STATUS (BUSY), meaning the Bank Teller is currently busy answering a Customer requests.
List of states and events:- Initially the Teller is busy in handling its Customers, TELLER_STATUS (BUSY) -> TELLER_STATUS (BUSY), still remains busy as a lot of Customers are waiting in the queue -> TELLER_STATUS (BUSY), still remains busy as a lot of Customers are waiting in the queue-> TELLER_STATUS (FREE), now the Teller is Free -> Bank-Tellers-Work (So, he asks the next Customer about his query) -> Operations Performed (Withdrawl), as per the Customer requests, the Teller performs the requested operation -> OPERATION_STATUS (Successful), the Teller updates the Customer about the transaction being performed.
Please let me know in case of any clarifications required. Thanks!