A14.1 The systems lifecycle and feasibility worksheet

The stages from feasibility to maintenance, the three kinds of maintenance, and scoring a feasibility study.

Questions 6 marks in all

[1 mark]Put these stages of the systems lifecycle in order.

Number the lines 1 to 6 to put them in the right order.

Feasibility study
Testing
Analysis
Implementation
Evaluation
Design

[1 mark]What is the purpose of a feasibility study?

ATo decide whether the project is possible and worth doing before money is spent on it
BTo find and fix the errors in the finished program
CTo write the program's user documentation
DTo train the users on the new system

[1 mark]A school opens a new wing, so the delivery robot's software is changed to include the new corridors. What kind of maintenance is this?

AAdaptive
BCorrective
CPerfective
DDestructive

[1 mark]Which of these are aspects considered in a feasibility study?

Tick every answer that is true.

ALegal
BEconomic
CSchedule
DSyntax
EPair programming

[1 mark]Against what should a finished system be evaluated?

AThe success criteria agreed during analysis
BHow much code was written
CWhether the developers enjoyed building it
DThe number of tests that were run

[1 mark]A feasibility study scores each aspect and weights it. What does this print?

aspects = [("technical", 4, 3), ("economic", 2, 2), ("legal", 5, 1)]
total = sum(s * w for _, s, w in aspects)
weights = sum(w for _, _, w in aspects)
print(total, weights, round(total / weights, 1))

The task: the feasibility study

Four robot projects have been scored for feasibility. proposals is a list of (name, aspects), where name is a string and aspects is a list of five tuples (aspect, score, weight): aspect is a string, score is a whole number from 0 to 5, and weight is a whole number from 1 to 3. Write two functions: - weighted_score(aspects) returns the total of score * weight divided by the total of the weights, rounded to one decimal place. - blockers(aspects) returns a list of the names of the aspects that score less than 2, in the order they appear. Then, for each proposal in order, print one line: <name>: <score> <verdict>, with the score to one decimal place. The verdict is not feasible (blocked by <aspects>) if there are any blockers, with their names separated by , ; otherwise not feasible (score below 3) if the score is less than 3; otherwise feasible. For example, delivery robot: 3.5 feasible. The robot stays still.

# the two lines every program starts with: the commands, then the robot
from bugbot import *
connect()

proposals = [
    ("delivery robot", [("technical", 4, 3), ("economic", 3, 2), ("legal", 4, 2), ("operational", 3, 2), ("schedule", 3, 1)]),
    ("face-recognition door", [("technical", 4, 3), ("economic", 4, 2), ("legal", 1, 2), ("operational", 3, 2), ("schedule", 4, 1)]),
    ("robot lawnmower fleet", [("technical", 3, 3), ("economic", 2, 2), ("legal", 3, 2), ("operational", 3, 2), ("schedule", 2, 1)]),
    ("voice-controlled lift", [("technical", 1, 3), ("economic", 1, 2), ("legal", 4, 2), ("operational", 3, 2), ("schedule", 4, 1)]),
]

def weighted_score(aspects):
    pass

def blockers(aspects):
    pass

Plan your program here, then type it in and press Run.

Do it on the robot
www.bugbotlab.com/learn/a14-1-the-systems-lifecycle/
The simulator checks it and tells you when it passes. Nothing to install, no account.

Challenges

The face-recognition door scores well overall but is blocked on legal grounds. Write two sentences explaining why a legal problem should stop a project that scores 3.2.

Classify each change as corrective, adaptive or perfective: the robot is updated for a new floor plan; a crash when the battery reads 0 is fixed; the route planner is made faster.

Suggest the changeover method you would use for the delivery robot, and justify it in terms of the risk to the school.

What this lesson is about

Questions 6 marks in all

The task: the feasibility study

Challenges