7. Systems Engineering (aka RE)

Question 1

What is the system engineering v-model?

Answer 1

V model: representation of systems development life cycle

1. project definition 
2. time ?? 
3. project test and integration

Question 2

What are stakeholders? Give examples

Answer 2

stakeholder: anyone with an interest in, or an effect on the outcome of the product
- customers: the users of the product
- clients: people who commission the product

Question 3

What are functional vs non-functional requirements?

Answer 3

functional requirements - specify what the system must do (behaviour of the system, how it interacts with users & other systems, capabilities it provides, information the system consumes and delivers)

non-functional requirements - requirements not directly concerned with the specific functions delivered by the system (define how the system must perform, look, feel + its response time, accuracy, reliability, cost, maintainability, authorised access policies)

Question 4

What are properties of a good system specification document?

Question 5

What is a UML use case diagram?

Answer 5

Use case: depicts interactions between system and the environment around the system by describing scenarios of operations of the system from the designer’s view. It is represented by a use case diagram

Question 6

What is a UML state diagram?

Answer 6

state (transition) diagrams - graphical models suitable for defining the dynamic, temporal behaviour of a system

Question 7

What is a UML activity diagram?

Answer 7

activity diagrams - modelling instrument that visualizes the workflow of a use case

Question 8

What are the definitions of errors/faults/failures. Give examples

Question 9

What are the V-model’s testing levels?

Answer 9

v model testing levels

1. unit testing ~ verifying each software module against its detailed low level design dynamic - executing software module for a particular set of inputs static - inspecting the code and trying to find errors test cases - set of inputs values, together with corresponding expected output values software under test - name of module while its being tested
2. integration testing ~ testing that verifies all the software modules integrated together against the architectural design
3. system testing ~ verifying the whole system against the system requirements specification and user scenarios 
4. acceptance testing ~ validating system against the wishes of the users (Note - step validates if system should be released or not)

Question 10

What is a hazard and how to perform hazard analysis using FTA, FMEA or STAMP?

Answer 10

hazards - things that could go wrong

hazard analysis - list of possible hazards or unsafe situations in a system

Question 11

How does an automatic insulin pump work?

Answer 11

Closed-loop automatic insulin pump: system that mimics the real time glucose regulating function of the pancrease in case of hyperglycemia.

Sensor measures BCG; value is sent to insulin pump controller; controller calculated required amount of insulin; user usually ends up actually administering that calculated amount not fully automatic

Question 12

What is a test case?

Answer 12

test cases: set of inputs values, together with corresponding expected output values

Question 13

What are testing techniques?

Answer 13

testing techniques - techniques to select a smart set of test cases that will discover the most amount of defects

• black box
• white box

Question 14

Examples of ethical questions

Question 15

Imagine we want to build a bionic eye that adds X-ray vision to a human and makes it possible to see through the walls. Identify two ethical questions related to this system.

Answer 15

Is it correct to look into peoples houses and break their privacy? Will a bionic eye possessor get a better job than a “normal” human being?