SYS SIM Lec 1 - 3 Quiz 1

Question 1

___ is the IMITATION of the operation of a
real-world process or system over time.

Answer 1

Simulation

Question 2

Either done by hand or on a computer, simulation involves the generation of an ______ of a system, and the observation of that is to draw _____ concerning the operating characteristics of the real system

Answer 2

– artificial history
– inferences

Question 3

___ Is the PROCESS of creating and analyzing a digital
prototype of a physical model to predict its performance in the real world

Answer 3

Simulation Modelling

Question 4

____ is a MATHEMATICAL MODEL that calculates the
impact of (uncertain) inputs and the decisions we make on the outcomes that we care about (such as profit, loss, investment returns, etc.)

Once developed and validated, it can be used to
investigate a wide variety of “what-if” questions and the potential changes to the system that can predict their impact on system performance

Answer 4

Simulation Model

Question 5

A Simulation model will include:
➢ ______ – these are the (uncertain) numbers/variables
➢ ______ (numerical parameters)
➢ ______ – these are the functions of interest

Answer 5

Model inputs
Intermediate calculations
Model outputs

Question 6

simulation modeling can be used both as an _____ tool for predicting the effect of changes to existing systems, and as a _____ tool to predict the performance of new systems under varying sets of
circumstances.

Answer 6

– analysis
– design

Question 7

When is Simulation the appropriate tool?

GIVE 7

(essay)

Answer 7

1. It enables the STUDY of, and EXPERIMENTATION with, the INTERNAL INTERACTIONS of a complex system, or of a subsystem within a complex system.
   (ex. System dynamics – growth & underinvestment)
2. The KNOWLEDGE gained in designing a simulation model may be of GREAT VALUE toward SUGGESTING IMPROVEMENT in the system under investigation
   (ex. Public transport systems, automation initiatives – warehouse, floor shop, etc.)
3. By changing simulation inputs and observing the resulting outputs, VALUABLE INSIGHT may be obtained into WHICH variables are most IMPORTANT and HOW variables INTERACT.
   (ex. Chemical reaction analyses)
4. It can be used to experiment with new designs or policies PRIOR to IMPLEMENTATION, so as TO PREPARE for what may happen. (ex. queueing model)
5. By simulating different capabilities for a machine, REQUIREMENTS can be DETERMINED.
   (ex. Production floor capacity adjustments, quality controls)
6. Its models designed FOR TRAINING allow learning without the cost and disruption of on-the-job learning.
   (ex. Flight simulations, military strategy simulations, race car driving, etc.)
7. The MODERN SYSTEM (factory, wafer fabrication plant, service organization, etc.) is so COMPLEX that the interactions can be treated ONLY THROUGH SIMULATION

Question 8

Essay: When is Simulation NOT the appropriate tool?

GIVE 6 RULES

Answer 8

First rule: when the problem can be solved using COMMON SENSE.

Second rule: if the problem can be SOLVED ANALYTICALLY.

Third rule: if it is EASIER to PERFORM direct
experiments.

Fourth rule: If the cost of the simulation study EXCEEDS the possible SAVINGS.

Fifth rule: if the resources (or time) is not available.

Sixth rule: If there is not enough time (or personnel) to verify and validate the model, then the simulation is not appropriate

Question 8

ESsay: Give 6 Simulation usage Advantages

Answer 8

1. REDUCED DISRUPTIONS of real-world operations.
2. New hardware designs, physical layouts, transportation systems (etc.) can be tested WITHOUT committing RESOURCES for acquisition.
3. Phenomenon/phenomena occurring can be tested FOR FEASIBILITY.
4. TIME can be compressed (or expanded) to the phenomena under investigation.
5. INSIGHTS can be obtained about the interaction of variables.
6. Helps to understand how the system operates rather than how individual thinks the system operates.
7. The “What-if” questions can be answered.

Question 9

4 Simulation usage Disadvantages

Answer 9

1. Model building requires special TRAINING.
2. Simulation results may be DIFFICULT TO INTERPRET
   – ex. an observation could either be a result of system interrelationships or randomness.
3. Simulation modelling and analysis can be TIME CONSUMING and EXPENSIVE.
4. Some closed-form models are not able to analyze most of the complex systems that are encountered in practice.

Question 10

3 Challenges and Limitations of Simulation

Answer 10

❑ Computational Complexity
o Large-scale simulations require high computing power.

❑ Data Accuracy & Assumptions
o Poor input data can lead to misleading results.

❑ Interpretation of Results
o Misinterpretation can lead to incorrect decisions

Question 11

One of the Main Types of Systems Simulation

__________
- Models systems where events occur at specific points in time.

ex. Bank teller queue simulation, Traffic light control in urban planning.

Answer 11

Discrete-Event simulation

Question 12

One of the Main Types of Systems Simulation

__________
- Models systems that change continuously over time rather than in discrete
steps.
ex. Climate modeling for weather predictions, Fluid dynamics simulations

Answer 12

2. Continuous Simulation

Question 13

One of the Main Types of Systems Simulation

_______
(combination of discrete and continuous – complex systems)
ex. discrete event for patient arrivals and continuous simul. for disease progression

Answer 13

Hybrid Simulation

Question 14

read only

SImulation: AReas for application

Answer 14

✓ Healthcare
▪ Simulating patient flow in emergency rooms
▪ Drug testing simulations before clinical trials

✓ Manufacturing & Logistics
▪ Production line optimization
▪ Design of a toll plaza
▪ Choosing between rental-car locations

✓ Business Process Simulation
▪ Bank connection redesign on airport gate assignment
▪ Personnel forecasting and strategic workforce planning

✓ Safety and Construction Engineering
▪ Crash test (virtual car) for Designing safer cars
▪ Testing proposed bridge design

Question 15

_____ are group of objects that are joined together in some regular
interaction or interdependence toward the accomplishment of some purpose

Answer 15

System

Question 16

T or F

In modelling systems, it is necessary to decide on the boundary between the system and its environment.

Answer 16

T

Question 17

5 components of a system

Answer 17

Entity
Attribute
Activity
State (Variables)
Events

Question 18

One of the components of a system:

___ is an object of interest in the system

Answer 18

Entity

Question 19

One of the components of a system:

___ is a property of an entity

Answer 19

Attribute

Question 20

One of the components of a system:

___ is an activity with a time period of specified length

Answer 20

Activity

Question 21

One of the components of a system:

___ that collection of variables necessary to describe the system at any time (relative to the objectives of the study)

Answer 21

State (variables)

Question 22

_____ is the representation of the real-world system for the purpose of studying that system.

➢ For most studies, it is necessary to consider only those aspects of the system that affect the problem under investigation

Answer 22

Model

Question 22

One of the components of a system:

_____ are instantaneous occurrences that may change the state of the system

Answer 22

Events

Question 23

2 types of Events a. _____ – activities/events occurring within the system b. _____ – activities/events in the environment that affect the system

Answer 23

Endogenous Exogenous

Question 24

3 types of Models of a system

Answer 24

1. Static/Dynamic models 2. Deterministic/Stochastic models 3. Discrete/Continuous models

Question 25

2 of the types of models _______ simulation – (Monte Carlo Simulation) represents a system at a particular POINT in time. (ex. car failure probability based on component failure data) *_______ simulation – represents the system as they CHANGE over time (ex. bank simulation from 9:00AM to 4:00PM, traffic flow simulation from 6:00AM to 11:00AM)

Answer 25

- STATIC SIMULATION - DYNAMIC SIMULATION

Question 26

One of the types of models ____ have KNOWN set of inputs which will result on a unique set of output

Answer 26

Deterministic models (ex. arrivals at a dentist’s office if all patients arrive at a scheduled appointed time)

Question 27

One of the types of models has one or more random variables as inputs (random inputs lead to random output)

Answer 27

Stochastic model Ex. Random inter-arrival times and random service times in a bank (output) average no. of people waiting, average no. of waiting time

Question 28

One of the types of models the state variables change only at a discrete set of points in time.

Answer 28

Discrete model

Question 29

One of the types of models The state variables change continuously over time. (ex. Water level of a dam with a lake behind the dam affected by weather through rain storm and evaporation)

Answer 29

Continuous model

Question 30

12 STEPS IN A SIMULATION STUDY (IN ORDER)

Answer 30

1 -- Problem Formulation 2 -- Setting Objective and OVerall Project Plan 3 -- Model Conceptualization 4 -- Data Collection 5 -- Model Translation 6 -- Model Verification 7 -- Model Validation 8 -- Experimental Design 9 -- Production runs and Analysis 10 -- More Runs? 11 -- Documentation and Reporting 12 -- Implementation

Question 31

One of the steps in Simulation Study: ____ is the determination whether simulation is the appropriate methodology for the problem as formulated in the objectives)

Answer 31

2 -- Setting Objective and OVerall Project Plan

Question 32

One of the steps in Simulation Study: __ is the selection of the application on where the model will be simulated (Arena, AutoMod, ProModel, Taylor Enterprise Dynamics, etc)

Answer 32

Model Translation

Question 33

One of the steps in Simulation Study: Question to be answered: is the computer program performing properly? (correct input parameters are checked with debugging

Answer 33

Model Verification

Question 34

One of the steps in Simulation Study: Questions: is the model an accurate representation of the real-system under study? It is usually achieved through model calibration (iterative model comparison of digital system to actual system behavior)

Answer 34

Model Validation

Question 35

One of the steps in Simulation Study: ____ are the alternatives that are to be simulated must be determined

Answer 35

Experimental Design

Question 36

One of the steps in Simulation Study: ______ are used to estimate the measures of performance for the system designs that are being simulated.

Answer 36

Production runs and analysis

Question 37

Type of Documentation and reporting a. ________ – necessary for understanding the program and possible future modifications. Parameter changes could analyze some output measure of performance. b. ________ – written history of a simulation project.

Answer 37

Program documentation Progress documentation

Question 38

____ is a powerful modeling technique used to represent and analyze complex systems where changes occur at discrete points in time

Answer 38

Discrete Event Simulation Note: focuses on specific events that trigger state changes in the system.

Question 39

This approach is particularly useful for systems where the timing and sequence of events are critical, such as queueing systems, manufacturing processes, and healthcare operations.

Answer 39

DES / Discrete Event Simulation

Question 40

___ is described by its calling population, the nature of the arrivals, the service mechanism, the system capacity, and the queueing discipline In the single-channel queue, the calling population is _____

Answer 40

-- queueing system -- infinite NOTE: ➢ In the single-channel queue, the calling population is infinite, ➢ Arrivals for service occur one at a time in a random fashion; once they join the waiting line, they are eventually served, ➢ service times are of some random length according to a probability distribution which does not change over time.

Question 41

Simulations of queueing systems generally require the maintenance of an ____ for determining what happens next. Simulation clock times for arrivals and departures are computed in a ____ customized for each problem

Answer 41

-- Event list -- simulation table

Question 42

Problem Solving https://www.youtube.com/watch?v=0aucm40TZxY