software engineering
DESCRIPTION
Software Engineering. SM ?. Outline of this presentation. What is SM The Need for SM Type of SM Size Oriented Metric Function Oriented Metric. Software Metric. A metric is a measurement of some aspect of the software product or the software process. Software Metric. What is SM. - PowerPoint PPT PresentationTRANSCRIPT
Software Engineering
SM?
1
Outline of this presentation
• What is SM• The Need for SM• Type of SM• Size Oriented Metric• Function Oriented Metric
221/04/23
Software Metric
• A metric is a measurement of some aspect of the software product or the software process
321/04/23
Software Metric
• We take metrics for a variety of reasons– to measure the quality of a product– to assess the productivity of the people
building the product– to assess the benefits (productivity and
quality) of new software tools– to form a baseline so we can estimate
for new tools– to help justify requests for new tools or
additional training
4
What is SM
21/04/23
Software Metric
• Software Development in general– has excessive costs • (especially in maintenance)
– low productivity– poor quality– lack of standards
5
The Need for SM
21/04/23
Software Metric
• Reasons being that we fail to:– set measurable targets–measure the real costs in projects– quantify the quality– properly evaluate new tools and
techniques
6
The Need for SM
21/04/23
Software Metric
• Size-oriented Metrics• Function-oriented Metrics• Technical Metrics• Human-oriented Metrics• Productivity Metrics• Quality Metrics
7
Types of Metric
Software Metric
• Size-oriented Metrics–direct measures of the output and quality of the SE process
• Function-oriented Metrics–indirect measures of the output and quality of the SE process
8
Types of Metric
Software Metric
• Technical Metrics–focus on the character of the software, e.g. coupling and cohesion
• Human-oriented Metrics–information about the method by which people build and use systems
9
Types of Metric
Software Metric
• Productivity Metrics–focus on the output of the software engineering process
• Quality Metrics–focus on the conformance of the software to the implicit and explicit user requirements (fitness for use)
10
Types of Metric
Software Metric
• Built on the past experiences of organisations
• Direct measures of the software• Generally based on the idea of
Line of Code or Source Line of Code
11
Size Oriented Metric
Software Metric
• Primary Examples:– Size of a product =
Kilo Lines of Code (KLOC)– Productivity = KLOC/person-month–Quality = number of faults/KLOC–Cost = $/KLOC–Documentation =
Pages of Documentation/KLOC
12
Size Oriented Metric (cont.)
Software Metric
Comments on Line of Code• Defined as one line of text in a source file• Modified by a number of factors
depending upon your Source Line of Code (SLOC) Counting Standard
• Simplest Standard– Don’t count blank lines– Don’t count comments– Count everything else
13
Size Oriented Metric
Software Metric
Advantages on Line of Code• Artifact of software development which
is easily counted• Many existing methods use LOC as a
key input• A large body of literature and data
based on LOC already exists
14
Size Oriented Metric
Software Metric
Disadvantages of Line of Code• Programming language-dependent• Well-designed, but shorter programs
are penalised• Does not easily accommodate non-
procedural languages• Reuse can be difficult to factor in• Difficult to develop a figure for LOC
early in the development
15
Size Oriented Metric
Software Metric
• Concentrate on measuring the functionality of a system
• Are generally independent of the programming language used
• The first and by far the most popular is the Function Point & Feature Point
16
FUNCTION Oriented Metric
Software Metric
• FUNCTION POINT– Developed by Albrecht in 1979 for IBM– Function points are derived using• countable measures of the software
requirements domain• assessments of the software complexity
17
FUNCTION Oriented Metric
Software Metric
18
FP = COUNT-TOTAL X [ 0.65 + 0.01 x Fi ]∑
where Fi are the 14 complexity adjustment values (gives ±35%)
Calculating Function Point
FUNCTION Oriented Metric
Software Metric
Calculating Count Total for Function Point based on:
• Number of user inputs• Number of user outputs• Number of user inquiries• Number of files• Number of external interfaces
19
FUNCTION Oriented Metric
Software Metric
• Number of user inputs– each user input which provides
distinct application data to the software is counted
• Number of user outputs– each user output that provides
application data to the user is counted, e.g. screens, reports, error messages
20
FUNCTION Oriented Metric
Software Metric
• Number of user inquiries– An on-line input that results in the generation
of some immediate software response in the form of an output
• Number of files– each logical master file, i.e. a logical grouping
of data that may be part of a database or a separate file
• Number of external interfaces– all machine-readable interfaces that are used
to transmit information to another system are counted
21
FUNCTION Oriented Metric
Software Metric
22
Weighting Factor
Measurement parameter Count Simple Average Complex Total
Number of user Inputs x3 x4 x6 =
Number of user outputs x4 x5 x7 =
Number of user Inquiries x3 x4 x6 =
Number of files x7 x10 x15 =
Number of external interfaces x5 x7 x10 =
COUNT TOTAL =+
?
Calculating Count Total
FUNCTION Oriented Metric
Software Metric
• We now assess the software complexity• Rate each of the factors on the next 2 slides according
to the following scale:– 0 - No influence– 1 - Incidental– 2 - Moderate– 3 - Average– 4 - Significant– 5 - Essential
23
Calculating Complexity Adjustment
FUNCTION Oriented Metric
14 Complexity Adjustment Questions 1. Does the system require reliable backup and recovery?2. Are data communications required?3. Are there distributed processing functions?4. Is performance critical?5. Will the system run in an existing, heavily utilised
operational environment?6. Does the system require on-line data entry?7. Does the on-line data entry require the input transaction
to be built over multiple screens or operations?
24
FUNCTION Oriented Metric
Software Metric
Software Metric
8. Are the master files updated on-line?9. Are the inputs, outputs, files or inquiries complex?10. Is the internal processing complex?11. Is the code designed to be reusable?12. Are conversion and installation included in the design?13. Is the system designed for multiple installations in
different organisations?14. Is the application designed to facilitate change and ease
of use by the user?
25
FUNCTION Oriented Metric
14 Complexity Adjustment Questions
Software Metric
Advantage• Programming language-independent• Based on data which are known
early in the project• Significant bodies of data available
26
FUNCTION Oriented Metric
Software Metric
Disadvantages• Developed for business systems and therefore
only valid for that domain ( Feature Points which extend Function Points
by also measuring algorithmic numbers solves this to some extent )
• Many aspects are subjective and have not been validated
• Function Points have no physical meaning, it’s just a number
27
FUNCTION Oriented Metric
Software Metric
28
Language Lines of Code per
Function Point
ADA 83 71
C 128
C++ 49
CLOS 27
COBOL 85 91
Eiffel 21
C++ 21
Smalltalk 21
Visual Basic 32
Small project : < 2000 Function Points
Medium Project : 2,000 to 10,000 Function Points
Large Project : > 10,000 Function Points
FUNCTION Oriented MetricSome Figures
Software Metric
29
FP = COUNT-TOTAL X [ 0.65 + 0.01 x Fi ]∑
where Fi are the 14 complexity adjustment values (gives ±35%)
Calculating Feature Point
FUNCTION Oriented Metric
Software Metric
Calculating Count Total for Feature Point base on
• Number of user inputs• Number of user outputs• Number of user inquiries• Number of files• Number of external interfaces• Number of algorithm
30
FUNCTION Oriented Metric
Software Metric
• Number of algorithm– all complex algorithm in creating program
and in every aspect of • Inputs• Outputs• Inquiries• Files• External interfaces
31
FUNCTION Oriented MetricCalculating Count Total for Feature Point
Software Metric
32
Weighting
Measurement parameter Count Factor Total
Number of user Inputs x4 =
Number of user outputs x5 =
Number of user Inquiries x4 =
Number of files x7 =
Number of external interfaces x7 =
Number of algorithm x3 =
Count total+
?
FUNCTION Oriented MetricCalculating Count Total for Feature Point
33
Terimakasih…..Untuk mahasiswa/i yang tidak ngantuk dan tetap konsentrasi
Mengikuti Perkuliahan.Sampai berjumpa minggu depan ……..
(Dalam perkuliahan dan dosen yang sama)