CSM/03/6/AS06 UNIVERSITY OF SURREY MSc Information Systems Level M Examination CSM03: Information Systems Development Time allowed: 2 hours Autumn Semester 2006 Answer THREE questions. Calculators are NOT permitted
CSM/03/6/AS06 - Page 2-1. This question is about UML Use Case Diagrams and Sequence Diagrams. Consider the following Scenario. This relates to the activities of a Cable TV Provider: In the offices of a Cables R Us, a cable TV provider, there is one helpdesk operator, who answers calls from customers, and three engineers, who maintain the cable network system. The company has many customers, who phone the helpdesk with enquiries. Existing customers will phone the helpdesk to request repair to their system if it is faulty, or to ask about upgrades (for instance to add more viewable channels. New customers often phone in requesting installation. The helpdesk operator always offers an upgrade, even to new customers, in case they would like to increase the channel selection they have already agreed upon. As a result of the call from a customer, the helpdesk may book one of the engineers. In this case, the helpdesk operator must consult the engineers schedule database and book an appointment. Installations for customers are always either upgrades or new installations. Each engineer records when he/she is available on the schedule database. All the engineers who maintain the network do installations or repairs. (a) From the first paragraph in the above scenario, draw a simple Overview Use Case Diagram, using the appropriate syntax. Ensure that you include an Answer Calls use case, referring to the responsibility of the helpdesk. [5 marks] (b) Using the further information in the second paragraph, in addition to that provided in the first paragraph, draw a Detail Use Case Diagram, using the appropriate syntax. You must indicate values clearly or provide a paragraph explaining your assumptions. You should consider the point of whether the database should be internal or external to the system. Explain your reasoning clearly. [16 marks] (c) Draw a Sequence Diagram for the Answer Calls Use Case to illustrate the above scenario, using the appropriate syntax. You should indicate values clearly that are passed in messages, or provide a paragraph explaining your assumptions. [12 marks]
CSM/03/6/AS06 - Page 3-2. This question is about UML Class Diagrams and Behavioural State Machines (State Chart Diagrams). (a) Explain the following terms, as used in an Object Oriented Systems Development: message, polymorphism and inheritance. Provide an example with each answer. (b) Consider the following scenario: Animals R Us is a zoo, in which there is a Monkey House, that contains monkeys all in one big cage, and a Cat House that contains an open-air lion enclosure and an open-air tiger enclosure. There is also a Bird House (Aviary), which contains birds in separate cages and one large enclosed cage that has birds flying free inside it. Animals R Us has a staff consisting of Administrators (who deal with business matters, such as allocating staff identification numbers to the Keepers) and the Keepers themselves (who look after the animals). Each big House (including the Aviary) has a separate Keeper, who feeds the animals every morning and cleans out their cages and enclosures every afternoon. Construct a UML Class Diagram using all the information provided in the above scenario. You should show aggregation, generalisation, and other associations, together with multiplicity, attributes and methods, where appropriate. [19 marks] (c) After a change of administrative staff at Animals R Us, it is decided that Keepers should be allocated a particular animal house for feeding and cleaning each day. So, the first thing that a Keeper must do when he/she gets into work in the morning is to obtain details of their Animal House for the day. At the end of the day, they have to hand in their worksheet detailing what actions they had carried out, and when they had been done. Only after doing this could they go home. Using the above extra information, in addition to that provided in the original Scenario in Q2(b), draw a UML Behavioural State Machine (State Chart) Diagram for an object of the Keeper class, using the appropriate syntax. [8 marks]
CSM/03/6/AS06 - Page 4-3. This question is about Information Systems Development Methodologies. (a) i) List the four main stages of the Systems Development Life Cycle (SDLC), giving a brief description of each stage. [8 marks] ii) What are the two main disadvantages of the Structured Design methodologies, in particular, the Waterfall methodology? [2 marks] (b) Consider the following scenario: As a systems analyst of a new biometric company, it is your job to decide what systems development methodologies to use for projects. New developments in technology have resulted in the invention of a new device that can instantly record the DNA profile of passengers passing through the security area in an airport. It is clear that the system will be complex, and contain many new devices and software, and you are sure this will be a new and untested field for the developers and engineers in your company. i) Your company always uses Rapid Application Development (RAD) systems development methodologies, in an attempt to overcome the disadvantages of Structured Design. Which RAD methodology or methodologies do you consider best for this project? Provide an explanation of your choice. [11 marks] ii) When starting to design the system, it becomes clear that the customer is not sure what kind of user interface is wanted, but the system must be reliable, as it would be a very bad idea for it to break down during a busy time. You have time if you act now to change the methodology to work best with these conditions. What methodology would you use now? Justify your choice and provide a diagram of your chosen methodology. [8 marks] (c) Agile Development is a third kind of systems development methodology. Extreme Programming (XP) is an example of Agile Development. Briefly describe one main difference between XP and the Rapid Application Development (RAD) systems development methodologies. [4 marks]
CSM/03/6/AS06 - Page 5-4. This question is about Requirements Determination (Information Gathering). (a) Consider the following list of questions used in an interview situation, in which you are trying to model a customer ordering system: (Note: Do not attempt to answer these questions yourselves!) 1. What information is missing from the monthly sales report? 2. What do you think about the current system? 3. How do you like your coffee? 4. Can you give me an example? 5. What improvements would you like to see in the new system? 6. Why? 7. What do you consider to be the biggest problem with the old system? 8. How many telephone orders are received each day? 9. What is your name? 10. What are some of the problems that you have each day? 11. How do customers place orders with the system? 12. Can you explain that in a bit more detail? i) Arrange all these twelve questions into the three categories: Closed-Ended Questions, Open-Ended Questions and Probing Questions. You may use the numbers above to refer to each question. ii) The most common method of ordering questions is to use a top-down approach. Arrange all these twelve questions into a sensible and realistic order in which they might be asked by the interviewer in such a top-down approach to interview questioning. Explain your answer clearly stating your reasons for your chosen order. (b) Consider the following scenario: You are the systems analyst for a Retail Systems company, and you have received instructions to design a new system for a well-known supermarket chain. This is an important customer, and so detailed analysis will be required to obtain a high depth of information regarding the system requirements. What do you consider to be the best requirements determination method or methods to use for this analysis? Justify your conclusions. [15 marks]
CSM/03/6/AS06 - Page 6 - (c) After a few initial discussions with representatives of the company, the following additional information was obtained: The customer considers that this new system must fit well with what the users want, that is, the checkout operators and back office staff, as well as being user-friendly and informative. This is because the management believe that the staff will work more efficiently if they like the system and find it useful. The problem is, such a system involves the integration of a lot of different computer systems (many of which are supermarket point-of sale terminals), including back office servers, some of which are MS-Windows based and some run the UNIX operating system, in a widely distributed network. Do you think you should now change the requirements gathering method from that/those given in your answer to Q4(b)? If so, what do you now consider to be the best requirements determination method or methods to use now for this analysis? Justify your conclusions. EXAMINERS: Dr J. Y. Clark Prof. R. Hierons