Kahoot

Question 1

Why do u need simulations
1. To obtain real user behaviour
2. Experiments with real system may b impossible
3. Analytical methods are not enough
4. To observe hardware defects

Answer 1

2 and 3

Question 2

What is not an objective of simulations
1. Demonstration
2. Evaluate future system
3. Measurements

Answer 2

3

Question 3

Which type of simulation yields results closer to real measurements
1. Abstract model based simulation
2. Detailed model based simulations
3. Hardware simulation

Answer 3

3.

Question 4

If you want to test the impact of rare events on your system what would you choose?
A: exp with actual s/m
B: physical model
C: Simulation

Answer 4

C

Question 5

What happens if we increase the time increments in a fixed increment DES?
A: accuracy in
B: accuracy de
C: speed increase
D: speed decreases

Answer 5

B and C

Question 6

What are the advantages of Next event TA with respect to fixed increment TA
1. Simpler implementation
2. More accurate
3. Faster
4: Less resource consumption

Answer 6

2.

Question 7

In a Next Event TA when is the event list created
A: before sim start
B: it is uploaded after every event
C: both are possible

Answer 7

C

Question 8

Which steps of a simulation study are in the correct order
A: sim design, problem def, execution
B: modeling, simulation design, execution
C: simulation design, analysis prob defn
D: prob defn, optimisation, sim design

Answer 8

B

Question 9

What are the two random process influence the state process of a queue
A: arrival and dropping process
B: arrival and service process
C: transition and dropping process
D: transition and service process

Answer 9

B

Question 10

For one server, which condition guarantees stability?

Arrival rate equal to service rate
Arrival rate lower than service rate
Service rate lower than arrival rate
First in first out

Answer 10

Arrival rate lower than service rate

Question 11

Which expression denotes a queue with 10 servers and
deterministic arrivals?
M/D/1/10
M/D/10/1
D/M/10/1
D/M/1/10

Answer 11

D/M/10/1

Question 12

In a M/M/1 system, what is the probability that the
system is idle? (ρ = λ/μ)
(1 - ρ)
ρ / (1 - ρ)
(1 - ρ) ρ
ρ / (1 - ρ)

Answer 12

(1 - ρ)

Question 13

What does it mean to be in state 4 of a Markov chain
modeling a one-server queue?
Four packets are in the buffer, the server is idle
Four packets are in the buffer, the server is busy
Three packets are in the buffer, the server is busy
The maximum size of the buffer is 4

Answer 13

Three packets are in the buffer, the server is busy

Question 14

Which of the following statistics are moments?
Median
Variance
Mean
Skewness

Answer 14

Variance
Mean
Skewness

Question 15

Which of the following statistics are measures of
central deviation?
Variance
Standard deviation
Mode
Expected value

Answer 15

Variance
Standard deviation

Question 16

If arrivals are independent, which distribution does the
inter-arrival time follow?
Weibull
Normal (gaussian)
Exponential
Uniform

Answer 16

Exponential

Question 17

By the central limit theorem, to which distribution does
a sum of i.i.d.r.v. converge?
Normal (gaussian)
Exponential
Binomial
Bernoulli

Answer 17

Normal (gaussian)

Question 18

Which of the following statistics re ect the asimmetry
of a PDF?
Variance
Skewness
Kurtosis
Mean

Answer 18

Skewness

Question 19

Which of the following distributions is discrete?
Normal
Exponential
Weibull
Binomial

Answer 19

Binomial

Question 20

In a memoryless system, what distribution models the
number of packet arrivals per second?
Beta
Exponential
Poisson
Weibull

Answer 20

Poisson

Question 21

What does the Chi-Squared test do?
Select the best PDF for your data out of several options
Reject a theoretical PDF for your data
Suggest a theoretical PDF for your data
Smooth out the empirical PDF

Answer 21

Reject a theoretical PDF for your data

Question 22

When cannot you use the inverse transform method?
When the distribution doesn’t have a closed form mean
When the distribution doesn’t have a closed form inverse CDF
When the distribution needs more than two parameters
When the distribution is not continuous

Answer 22

When the distribution doesn’t have a closed form inverse CDF

Question 23

What is NOT necessary for a stochastic process to be
covariance-stationary?
Stationary mean
Same covariance between any two samples
Finite variance
Same covariance between samples with the same lag

Answer 23

Same covariance between any two samples

Question 24

Which distribution does the sample mean of many
samples of a beta-distruibuted r.v. follow?
Exponential distribution
Normal distribution
Beta distribution
Weibull distribution

Answer 24

Normal distribution

Question 25

What is the distinguishing feature of the steady-state
phase of a simulation?
Samples follow the same distribution
Samples have the same value
Samples have approximately the same value
Samples follow a normal distribution

Answer 25

Samples follow the same distribution

Question 26

Given the true mean μ, the sample mean x̅ and the resampled
mean x̅, what is true?
x̅ is a better approximation to μ than x̅
x̅-μ follows a similar distribution to that of x̅-x̅
The con􀁽dence interval of x̅ is smaller than that of x̅
μ and x̅* follow the same distribution

Answer 26

x̅-μ follows a similar distribution to that of x̅*-x̅

Question 27

Which is true? In a process-oriented simulation…
… there are no events, but processes.
… all events belong to a process.
… there is only one event list.
… simulation time is real time.

Answer 27

… all events belong to a process.

Question 28

Which two OSI layers have no direct equivalent on the
TCP/IP internet model?
Presentation and session layers
Application and transport layers
Transport and network layers
Application and datalink layers

Answer 28

Presentation and session layers

Question 29

What is the main difference between TCP Tahoe and
TCP Reno
“Reno” sounds cooler
The steady-state phase: linear vs. exponential
Fast recovery or not
Reno is older than Tahoe

Answer 29

Fast recovery or not

Question 30

This network graph has 12 nodes and 18 edges. What is
its average node degree?
2/3
4/3
3
1.5

Answer 30

3

Question 31

In the graph shown, what is the betweenness centrality
of node A?
1 + 2 + 3 + 4 + 5 = 15
1 + 2 + 3 + 4 = 10
(1 + 2 + 3 + 4 + 5) / 2 = 7.5
5! = 120

Answer 31

1 + 2 + 3 + 4 = 10

Question 32

In which model new nodes are more likely to connect to
nodes with high node degree?
Erdos and Renyi model
Waxman model
Barabasi-Albert model
Snowman model

Answer 32

Barabasi-Albert model

Question 33

What is the diameter of a BCubek network?
k+1
k - 1
1
k

Answer 33

k + 1