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Cork Institute of Technology
Bachelor of Engineering in Communications Systems - Award
(NFQ Level 7)
Summer 2006
Communications Software Development
(Time: 2 Hours)
Answer THREE questions. Examiners: Mr. F. O’Reilly Mr. J. Berry Dr. R. O’Dubhghaill
Q1 (a) Compare and contrast the Waterfall and Iterative Refinement models of software development. Provide examples/project type where each may be useful? (8 marks)
(b) Categorise the following requirements into Functional and non-Functional for an ATM system interface. You can use the reference numbers to speed your answer. (1) The Interface should be useable by customers with a reading age of 12 (2) The ATM machine must validate the account with the PIN before starting the transaction. (3) Balance Checks, Cash Withdrawals and Bill Payments should be presented as options to customers. (4) Service Documentation, describing re-loading, upgrading and standard problems is provided. (5) If a customer fails to complete a transaction in 2 minutes the card is swallowed. (5 marks)
Choose one of the following specification approaches to describe the requirements of an ATM transaction and describe a standard cash withdrawal with it. Decision Table, Data Flow model, FlowChart, Pseudo Code, State Transition Diagram. (8 marks)
(c) Batch Processing Systems, Web Interfaces with CGI /Java Scripts, Distributed Forwarding Protocols and Embedded Real time Systems are four architectural choices. For the following applications choose what you think is the most appropriate architecture explaining your choice briefly.
CIT student record system which allows real-time lookup MP3 Music Player with radio interface. Phone Bill Generation Software E-mail system for use between remote African villages. (13 marks) (Total: 34 marks)
Q2 (a) The Fourier transform, as shown below in two forms, is a widely used mathematical transform on incoming signals.
F jw ∫ f t e jwt dt
+∞ −∞
=
=^1 − Ω
0
N n
F jw x nT e jk nT
Explain what it does, and how it would be applied to an incoming signal as coming from a digital sampling circuit. What challenges do the implementation of the above forms pose? What solutions are available, describing how the solution works? (16 marks)
(b) A Finite Impulse Response (FIR) Filter can be used to band-limit digital signals before transmission down a frequency limited channel.
−
1 0
N k
y n h n x n k
Describe the operation of the algorithm to implement it, using either diagrams or peusdo- code paying particular attention to the number of co-efficients, taps and the number of samples used. What is the difference between an FIR Filter and an IIR Filter? (18 marks)
Q4 (a) A process on a multi-tasking system, generally goes through a number of states in its existence. Draw a diagram which shows the 5 different states, explaining what each one is and the progression to the next state. (8 marks)
What is used to keep track of each process and what does it contain? What is the term used to describe switching from one process to another? (6 marks)
(b) Give bullet points explaining the features and advantages/disadvantages of the following scheduling algorithms. Shortest Job First Priority Scheduling Round Robin (9 marks)
(c) Draw a UML diagram to model a range of automobiles. This model may be used in an internet based driving game. The main elements of an automobile which interact are:
- Body
- 4 Driving Wheels
- Engine & Engine Management System
- Fuel Tank with a petrol gauge.
- 2 or 4 Seats depending on the car.
- 1 - 4 passengers in the car
- Driving Controls (Steering Wheel, Pedals, gear Control) (11 marks)
