[SOLVED] network Beijing-Dublin International College

Beijing-Dublin International College
__________________________________________
SEMESTER I EXAMINATION 2018/2019 ___________________________________________
School of Computer Science
BDIC Final Exam COMP3014J Performance of Computer Systems
HEAD OF SCHOOL: Padraig Cunningham MODULE COORDINATOR: Lina Xu*
Time Allowed: 120 minutes
Instructions for Candidates
All questions carry equal marks. The distribution of marks in the right margin shown as a percentage gives an approximate indication of the relative importance of each part of the question.
BJUT Student ID: ________________ UCD Student ID: ________________
I have read and clearly understand the Examination Rules of both Beijing University of Technology and University College Dublin. I am aware of the Punishment for Violating the Rules of Beijing University of Technology and/or University College Dublin. I hereby promise to abide by the relevant rules and regulations by not giving or receiving any help during the exam. If caught violating the rules, I accept the punishment thereof.
Honesty Pledge:_____________________________________________ (Signature)
Instructions for Invigilators
Non-programmable calculators are permitted.
No rough-work paper is to be provided for candidates.

BDIC Semester One Academic Year (2017 2018)
Obtained score
20
Question 1: General Theories on Performance
1. Whatarethethreecommonperformanceevaluationtechniquesandwhentouse them? Talk a little bit about their advantages and disadvantages. (6 Marks)
2. Whatwillbethemainconcernswhendecidingwhichsimulatortouseforsystem evaluation? List four of those you think are important.
(4 Marks)
3. Randomnumbergenerationisoftenrequiredtogeneratesyntheticdata.Linear- Congruential Generators are the popular ones that can be applied efficiently. List at least three factors that you can use to determine whether a random number sequence is good or not. (10 Marks)
Question 2: Workload Characterization
1. Whatarethedifferencesbetweenfactorsandparameters?Presenttheanswerin your own words and also give some examples for both. (5 Marks)
2. Inthiscasethiswasasmallsurveytoonlyafewpeople,whereeachperson answered six attitudinal questions and a question regarding how often they visit the mall, all on a scale 1-7, as well as one question regarding their household income. Based on the information below, who do you think person ID 1 would enjoy shopping with? Demonstrate your conclusion step by step.
(15 Marks)
Obtained score
25
Page 2 of 6

BDIC
Semester One
Academic Year (2017 2018)
ID
V1
V2
V3
V4
V5
V6
Income
Mall.Visits
1
6
4
7
3
2
3
60000
3
2
2
3
1
4
5
4
30000
1
3
7
2
6
4
1
3
70000
3
4
4
6
4
5
3
6
30000
7
5
1
3
2
2
6
4
60000
1
6
6
4
6
3
3
4
50000
2
7
5
3
6
3
3
4
65000
3
8
7
3
7
4
1
4
55000
4
9
2
4
3
3
6
3
70000
0
10
3
5
3
6
4
6
25000
6
Name Description
V1 Shopping is fun
V2 Shopping is bad for your budget 1-7
V3 I combine shopping with eating out 1-7 V4 I try to get the best buys while shopping 1-7
V5 I dont care about shopping 1-7
V6 You can save lot of money by comparing prices 1-7 Income The household income of the respondent Dollars
Mall.Visits How often they visit the mall 1-7
3. Whenobservingthetrafficinalocalnetwork,weknowthatsmallpackets=87.5%; large packets = 12.5%. The transition matrix between state small packet (S) and sate large packet (L) is like below. What is the chances to get a small packet for the 20th packet if the current packet is a small one (the current one can be seen at the 0th one) (5 Marks)
Question 3: Summarize Measured Data
1. Using a Q-Q plot to test for normality, the data is likely normal if: (5 Marks)
a) The Q-Q plot shows that all the data is on the x-axis
b) The Q-Q plot is a close to positively sloped straight line
c) TheQ-Qplotshowsallofthedataisabovea45-degreelinefromtheorigin d) The Q-Q plot shows a pattern
Scale 1-7
Obtained score
25
Page 3 of 6

BDIC Semester One Academic Year (2017 2018)
2. Scoresfor10studentsare:
81, 78, 85, 80, 86, 82, 83, 80, 87, 85
Are the results following Normal distribution? Demonstrate your answer step by step. (10 Marks)
3. Mc Donalds is also considering changing pickle suppliers. With the current supplier, each Mc Donalds pays an average of 1 cent per pickle. A rival in a sample of 49 pickle prices from a rival supplier (pickle prices vary by region due to shipping costs etc.) The average price was 0.9 cents per pickle with a standard deviation of 0.02 cents. Should we switch suppliers? Explain why or why not. (10 Marks)
Question 4: Queuing Model
1. Cars arrive at a small gas station to refuel according to a Poisson process with rate 30 per hour and have an exponential service time distribution with mean 4 minutes. Since there are four gas pumps available, four cars can refuel simultaneously, but unfortunately there is no room for cars to wait. Hence, if a car arrives when all pumps are busy, the driver leaves immediately. For each customer that is served, an average profit is made of 7 euros.
a) Determinetheprobabilitythatanarrivingcarisnotrefueled.(15Marks) b) What is the long-run expected profit per day (consisting of eight hours)?
(5 Marks)
2. Someday, one manager has the opportunity to buy an adjacent parking lot, so there is room to wait for all cars that arrive when the four pumps are busy. Suppose all drivers decide to wait instead of leaving when this happens. Another manager wants to buy two new gas pumps to increase the serving rate. Supposedly buying the car park space is the same as buying the two gas pumps. Which suggestions do you thinking is better?
(10 Marks)
Obtained score
30
Page 4 of 6

Appendix :
BDIC Semester One Academic Year (2017 2018)
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BDIC Semester One Academic Year (2017 2018)
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