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Invitation to Computer Science

G.Michael Schneider, Judith Gersting

Chapter 13

Simulation and Modeling - all with Video Answers

Educators


Chapter Questions

02:36

Problem 1

You are probably familiar with the idea of a twodimensional spreadsheet, like the ones created in Microsoft Excel. Would you call this type of spreadsheet a "computational model"? State why or why not, and justify your answer.

AG
Ankit Gupta
Numerade Educator
02:58

Problem 2

Look up the definition of the terms computer-aided design (abbreviated CAD) and computer-aided manufacturing (CAM). Find out what they mean, how they are used, and how they relate to the ideas presented in this chapter.

Kelsey Dondelinger
Kelsey Dondelinger
Numerade Educator

Problem 3

Rather than using a general-purpose programming language like the ones discussed in Chapter 9 , models are often constructed using simulation languages designed specifically for this application. (These languages fall into the category of "specialpurpose languages" mentioned in Chapter 10.) Examples of simulation languages include:
- SIMULA
- GPSS (General Purpose System Simulation)
- Simscript
Read about one of these languages and discuss what features make it well suited for implementing simulation models.

Check back soon!
01:01

Problem 4

In Section 13.2.2, we specified two inaccuracies in the equation describing a body falling under the influence of gravity: the problems of air resistance and the fact that the Earth is not a perfect sphere. Are there additional inaccuracies contained in this mathematical model? Do you think that these other factors should be included in our falling body model? Explain why you believe they do or do not need to be included.

Narayan Hari
Narayan Hari
Numerade Educator
01:25

Problem 5

In this chapter, we described a way to model a statistical distribution by using random numbers generated by a computer. How do you think it is possible for a computer to generate a truly random number that successfully passes all tests for randomness? Read about random number generators and discuss the aigorithms that they use.

James Kiss
James Kiss
Numerade Educator
05:00

Problem 6

In Section 13.2.3, we specified the statistical distribution for the sevvice time in our McBurgers restaurant: $5 \%$ of customers were served in less than 1 minute, and so forth. Do you think this is an accurate distribution of service times in realworld take-out restaurants? Why or why not? If this distribution is not an accurate portrayal of the customer service time, what are the implications of this inaccuracy on our model?

Robin Corrigan
Robin Corrigan
Numerade Educator

Problem 7

Describe how the customer arrival and departure event algorithms (Figures 13.4, 13.7) and the main algorithm (Figure 13.8) of our McBurgers simulation would change if we changed the system in each of the following three ways:
a. Instead of a single waiting line, we have $N$ waiting lines, one for each of the $N$ servers in the restaurant. That is, our model now behaves as shown:
b. The waiting line has a maximum length of MAX. If the length of the waiting line is currently less than MAX, then the customer gets into line in exactly the same way as in the current model. However, if the waiting line has a length equal to MAX, then the customer leaves the store without being served.
c. Each customer is assigned a priority when first entering the store (a value from 1 to 10 ), and if there is no server currently available, the customer goes into the waiting line in priority order. That is, a customer gets into line ahead of all people with lower priority and behind everyone with an equal or higher priority.

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Problem 8

In the McBurgers simulation, our model assumes that the arrival distribution of customers is the same throughout the entire day. Do you think this is a realistic assumption? If not, explain how you could modify the model to make it a better representation of customer arrivals in real life.

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08:11

Problem 9

Do you think that inclusion of the following parameters in the McBurgers model would or would not increase the accuracy of the model and its ability to predict real-world behavior?
a. Age of the customer
b. Sex of the customer
c. Height of the customer

Teresa Wray
Teresa Wray
Numerade Educator
08:18

Problem 10

Assume that you want to model a bus system in which passengers purchase tickets and travel from city A to one of four other cities, either B, C, D, or E. An important part of the model is determining to which city a specific passenger is traveling, a random variable. How might you go about creating a statistical distribution that accurately specifies to which of these four cities a passenger will buy a ticket and travel?

Robin Corrigan
Robin Corrigan
Numerade Educator
02:25

Problem 11

Do you think a computational model of elementary particles being created and destroyed by collisions in a high-speed accelerator would be discrete or continuous?

Vysakh M
Vysakh M
Numerade Educator
03:32

Problem 12

a. Assume our model requires $10^{14}$ computations to simulate one hour of activity. We run the program on a desktop computer with a computation speed of 800 MIPS (millions of instructions per second). How long will it take to simulate one day of activity in the model?
b. How fast a computer (in terms of MIPS) do we need to use if we want to complete the simulation of one day in five minutes of computing time?

Trinity Steen
Trinity Steen
Numerade Educator
01:02

Problem 13

We discussed the use of color and scale to enhance and highlight aspects of a data set being studied. In addition to these two features, suggest other ways to visually enhance the output of a model that will help to clarify its interpretation.

Hossam Mohamed
Hossam Mohamed
Numerade Educator
View

Problem 14

In this chapter, we focused our discussions primarily on the uses of modeling in the physical sciences, life sciences, economics, and engineering. However, the use of models is certainly not limited to these areas. Read about
how simulation models are currently used to conduct research in the social sciences and humanities, such as the fields of anthropology, sociology, and political science. Write a report describing the uses of computational modeling in one of these fields.

James Kiss
James Kiss
Numerade Educator
01:45

Problem 15

Read about how simulation models are being used in your own specific field of study, and write a report on exactly what these models do and what type of research is being done using them.

Carson Merrill
Carson Merrill
Numerade Educator