Kahoot Flashcards
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
2 and 3
What is not an objective of simulations
1. Demonstration
2. Evaluate future system
3. Measurements
3
Which type of simulation yields results closer to real measurements
1. Abstract model based simulation
2. Detailed model based simulations
3. Hardware simulation
3.
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
C
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
B and C
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
2.
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
C
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
B
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
B
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
Arrival rate lower than service rate
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
D/M/10/1
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)
(1 - ρ)
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
Three packets are in the buffer, the server is busy
Which of the following statistics are moments?
Median
Variance
Mean
Skewness
Variance
Mean
Skewness
Which of the following statistics are measures of
central deviation?
Variance
Standard deviation
Mode
Expected value
Variance
Standard deviation
If arrivals are independent, which distribution does the
inter-arrival time follow?
Weibull
Normal (gaussian)
Exponential
Uniform
Exponential
By the central limit theorem, to which distribution does
a sum of i.i.d.r.v. converge?
Normal (gaussian)
Exponential
Binomial
Bernoulli
Normal (gaussian)
Which of the following statistics re ect the asimmetry
of a PDF?
Variance
Skewness
Kurtosis
Mean
Skewness
Which of the following distributions is discrete?
Normal
Exponential
Weibull
Binomial
Binomial
In a memoryless system, what distribution models the
number of packet arrivals per second?
Beta
Exponential
Poisson
Weibull
Poisson
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
Reject a theoretical PDF for your data
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
When the distribution doesn’t have a closed form inverse CDF
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
Same covariance between any two samples
Which distribution does the sample mean of many
samples of a beta-distruibuted r.v. follow?
Exponential distribution
Normal distribution
Beta distribution
Weibull distribution
Normal distribution
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
Samples follow the same distribution
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 condence interval of x̅ is smaller than that of x̅
μ and x̅* follow the same distribution
x̅-μ follows a similar distribution to that of x̅*-x̅
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.
… all events belong to a process.
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
Presentation and session layers
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
Fast recovery or not
This network graph has 12 nodes and 18 edges. What is
its average node degree?
2/3
4/3
3
1.5
3
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
1 + 2 + 3 + 4 = 10
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
Barabasi-Albert model
What is the diameter of a BCubek network?
k+1
k - 1
1
k
k + 1
