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WXGC6103 Software Metrics

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First half - measurement concepts, the importance, framework, data collection. Second half measurement techniques and models: ... Galileo Galilei (1564 - 1642) ... – PowerPoint PPT presentation

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Title: WXGC6103 Software Metrics

1
Introduction

WXGC6103 Software Metrics
Pn Zarinah Mohd Kasirun
AD14 (Main Building)
zarinahmk_at_um.edu.my
Pn Siti Hafizah Hamid
D3 (Annex Building)
sitihafizah_at_um.edu.my

2
Course Contents

Proforma
Course Current Info. (Maklumat Semasa)
First half - measurement concepts, the
importance, framework, data collection.
Second half measurement techniques and models
products, processes and resources, plan.

3
Assessment

Final exam 40
Continuous assessment 60
ZMK- 30
SH-30

4
Learning outcome

After finish this course you should be able to
Describe the importance of software measurements.
Identify and describe the different techniques of
software measurements.
Apply the various techniques related to the
measurement of product and process quality.
Determine and apply the relevant techniques to
improve product development management.

5
Measurement what is it and why do it?

Learning outcome After finish this topic you
should be able to
describe measurements essential role in good
software engineering practice.
1.1 Measurement in everyday life
1.2 Measurement in SE
1.3 The scope of SM
1.4 Summary

6
1.1 Measurement in everyday life

Software measurement is essential to good SE.
Software developer (meeting requirements, quality
of design, ready to test code)
Project manager (measure attribute of process and
product - when to deliver product and within
budget)
Customer (final product meet requirement and of
quality)
Maintainers (what should be upgraded and
improved)

7
1.1 Measurement in everyday life

Measurement lies at the heart of many systems.
We use it everyday
Price
Total Bill
Height and Size
Distance, Speed, predict time of arrival
Help us to understand our world, interact with
the surroundings and improve our lives.

8
1.1 Measurement in everyday life

What is measurement?
Some aspect of a thing is given a descriptor that
allow us to compare it with others.
Definition Measurement is the process by which
numbers or symbols are assigned to attributes of
entities in the real world in such a way as to
describe them according to clearly defined rules.
Captures info about attributes of entities.
Entity - object or event
Attribute - feature or property of an entity.

9
1.1 Measurement in everyday life

What is measurement?
We measure attributes of things.
Define the attributes using number or symbols.
For eg price (, RM), height (cm, inch), size
(small, medium, large)
Number or symbols are abstraction used to reflect
our perceptions of the real world.

10
1.1 Measurement in everyday life

Making things measurableWhat is not measurable
make measurable Galileo
Galilei (1564 - 1642)
Measuring the unmeasurable should improve our
understanding of particular entities and
attributes, making SE as powerful as other
engineering disciplines.
Important software attributes (dependability,
quality, usability and maintainability) according
to some are not quantifiable but should try to
measure in order to better understand them.

11
1.1 Measurement in everyday life

Two kinds of quantification
Measurement - direct quantification (e.g. measure
the height of a tree)
Calculation - indirect quantification (take
measurement and combine them into a quantified
item)

12
1.1 Measurement in everyday life

In SE
Overall score that combines several measures into
a big picture of what is going on during
development or maintenance.
The good or bad of software based on a set of
measures, each of which captures a facet of
goodness,
Controversy in capturing qualitative information
about some aspects in SE.
Modify the environment or practices to measure
something new or in a new way using new tool,
add new step in a process, using new method

13
1.2 Measurement in SE

SE describes the collection of techniques that
apply an engineering approach (each activity is
understood and controlled) to the construction
and support of software products.
SE activities managing, costing , planning,
modeling, analyzing, specifying, designing,
implementing, testing and maintaining.

14
1.2 Measurement in SE

Computer science provides the theoretical
foundations for building software, SE focuses on
implementing software in a controlled and
scientific way.
Software engineers continue to improve process
and product.

15
1.2 Measurement in SE

It has been noted frequently that we are
experiencing a software crisis, characterized by
our inability to produce correct , reliable
software within budget and on time.
These failures are caused by the inherent
complexity of the software dev. process, for
which there is no analytical description.
Improve our software management capabilities
including the development of improved software
metrics and improved utilization of such metrics.

16
1.2 Measurement in SE

For most development projects
Fail to set measurable targets for software
product (user-friendly, reliable and maintainable
without specify clearly and objectively what
these terms mean, hence unable to tell if goals
had been made)Gilbs Principle of Fuzzy Targets
projects without clear goal will not achieve
their goal clearly
Fail to understand and quantify the component
cost of software project.

17
1.2 Measurement in SE

For most development projects
Do not quantify or predict the quality of the
products
Try revolutionary new development technology
without determining whether if it is efficient
and effective (with scientific basis support).
Fig 1.1
Lack of measurement in SE is compounded by the
lack of a rigorous approach.

18
1.2 Measurement in SE

Objectives for software measurement
To assess the status of projects, products,
processes and resources. It is essential that we
measure and record characteristics of good
projects as well as bad.
Must control projects
You cannot control what you cannot measure
(DeMarco)
Every measurement action must be driven by a
particular goal or need that is clearly defined
and easily understandable.

19
1.2 Measurement in SE

Managers perspective
What does each process cost?
How productive is the staff?
How good is the code being developed?
Will the user be satisfied with the product?
How can we improve?

20
1.2 Measurement in SE

Engineers perspective
Are the requirement testable?
Have we found all the faults?
Have we met our product or process goals?
What will happen in the future?

21
1.2 Measurement in SE

Measurement for understanding, control and
improvement.
Understand what is happening during development
and maintenance, relationship among activities
and the entities they affect.
Control what is happening on our projects.
Improve process and product
Users of the data must be aware of the limited
accuracy of prediction and of the margin of error
in the measurements.

22
1.2 Measurement in SE

As with other engineering discipline, there is
room in software engineering for abuse and misuse
of measurement.
If you are expecting measurement to provide
instant, easy solutions to your engineering
problems, be aware of this
You can neither predict nor control what you
cannot measure (DeMarco)

23
1.3 The scope of software metrics