Chapter 3 : System Analysis

TOPIC 3:

SYSTEM ANALYSIS

(1)

•

Conduct preliminary analysis

•

Understand data and process modeling

CONDUCT PRELIMINARY ANALYSIS

 System developers must identify and describe all system

requirements.

 System Requirements are a characteristics or features that must

be included in an information system to satisfy business
requirements and be acceptable to users.

 Five categories of system requirements

• Outputs
• Inputs
• Processes
• Performance
• Controls

SYSTEM REQUIREMENTS

CONDUCT PRELIMINARY ANALYSIS

 Outputs

• The Web site must report online volume statistics every four

hours, and hourly during peak periods

 Inputs

• The department head must enter overtime hours on a separate

screen

 Processes

• The student records system must calculate the GPA at the end

of each semester

 Performance

• Response time must not exceed four seconds

 Controls

• An employee record must be added, changed, or deleted only

by a member of the human resources department

SYSTEM REQUIREMENTS

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

INTERVIEWS

DOCUMENTATION REVIEW

OBSERVATIONS

QUESTIONNAIRE

SAMPLING

RESEARCH

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

1. INTERVIEWS

An interview can
take more time to
organize and it is
extremely difficult to
repeat so it is vital
that the questions
asked are the right
ones.

Objective:

Find facts

Verify facts

Clarify facts

Generate enthusiasm

Get the end-user involved

Identify requirements

Solicit ideas and opinion

The personal interview is generally recognized as
the most important and most often used fact-
finding technique.

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

1. INTERVIEWS

Types of Interviews
and Questions

Unstructured
Structured
Open-ended
question
Close-ended
question

Unstructured interview: Conducted with only a
general goal or subject in mind and with few, if any,
specific questions. The interviewer counts on the
interviewee to provide a framework and direct the
conversation.

Structured interview: Interviewer has a specific set
of questions to ask of the interviewee.

Open-ended question: Question that allows the
interviewee to respond in any way.

Closed-ended question: A question that restricts
answers to either specific choices or short, direct
responses.

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

1. INTERVIEWS

What is the ADVANTAGES
and DISADVANTAGES of

interviews?

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

1. INTERVIEWS

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

1. INTERVIEWS

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

2.
DOCUMENTATION
REVIEW

All documents which are used within a

system need to be review.

These will be eventually duplicated or

replaced with alternative versions or even

discarded in the new system.

Types of document which need to review:

Data capture forms

System documentation

Business reports

Invoices

Bills

borang pendaftaran
prcedure, laporan kewangan
tahunan, resit, billing inventory,

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

3. OBSERVATION

The aim of
observation is to
find out what
actually happens,
not what the
workers think
observers expected
to see.

The target is to see who does what in an

organization and what information they do

it with.

By simply watching people working it is

also fairly straightforward to watch how

data flow around a system.

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

3. OBSERVATION

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

3. OBSERVATION

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

3. OBSERVATION

Guidelines:

Determine the who, what, where, when, why
and how of the observation

Obtain permission from appropriate
supervisor

Inform those who will be observed of the
purpose of the observation

Keep a low profile

Take notes

Review observation notes with appropriate
individuals

Don’t make assumptions

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

4.
QUESTIONNAIRE

Free-format questionnaire

A question is asked and the

respondent records the answer in the

space provided after the question

Fixed-format questionnaire

Contain questions that require

selecting an answer from predefined

available responses.

A great deal of time is spent on preparing
questionnaires in order that the right type of
question is asked in order that the most relevant
information is gathered.

open question : pendapat, comment, cadangan

close question: pilihan jawapan

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

4.
QUESTIONNAIRE

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

4.
QUESTIONNAIRE

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

4.
QUESTIONNAIRE

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

4.
QUESTIONNAIRE

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

5. SAMPLING

Process of
collecting sample
documents, forms,
and records

Use sampling techniques to get a large
enough cross section to determine what
can happen in the system.

When studying documents or records
from a database table, you should study
enough samples to identify all the
possible processing conditions and
exceptions.

The size of the sample depends on how
representative you want the sample to be.

Two commonly used sampling techniques
are randomization and stratification

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

5. SAMPLING

Randomization

A sampling technique

characterized as

having no

predetermined pattern

or plan for selecting

sample data.

Stratification

A systematic sampling
technique that attempts
to reduce the variance

of the estimates by
spreading out the

sampling

CONDUCT PRELIMINARY ANALYSIS

TECHNIQUES USED IN FACT FINDING

6. RESEARCH

Research the
application and
problem

Computer trade journals and reference books
are a good source of information.

Exploring the internet and world wide web
(WWW) via personal computer can provide a
immeasurable amounts of information.

Corporations use the internet as an effective
means of communicating with their
employees

CONDUCT PRELIMINARY ANALYSIS

FUNCTIONAL DECOMPOSITION DIAGRAM (FDD)

Function decomposition is the decomposing of a system into its
component functions and processes as a way of managing complexity

Function decomposition creates a top-down view: it shows a hierarchy
of levels of increasingly detailed processes within a system

A function decomposition model or diagram (FDD) is used to represent
the hierarchical decomposition and structure of the processes of a
system

The decomposition of functions corresponds to levelling of processes in
DFDs

FDD show the structure of functions and processes within the system

CONDUCT PRELIMINARY ANALYSIS

FUNCTIONAL DECOMPOSITION DIAGRAM (FDD)

Each function and process should have a unique name which indicates
what it does

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Visualizing - a picture is worth a thousand
words; a graphical notation articulates and
unambiguously communicates the overall view
of the system (problem-domain).

UML is a modeling language for visualizing, specifying,
constructinganddocumentingthe artifacts of software

systems.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Specifying - UML provides the means to model
precisely, unambiguously and completely, the
system in question.

Constructing - models built with UML have a
“design” dimension to it; these are language
independent and can be implemented in any
programming language.

UML is independent of
 any software development process

• A process that adopts UML must support an object-oriented

approach to software production

 implementation technologies (as long as they are object-oriented)

• This makes UML somewhat deficient in supporting the detailed

design phase of the development lifecycle

 Unified Modeling Language (UML) combines techniques from data

modeling (entity relationship diagrams), business modeling (work
flows), object modeling, and component modeling.

 It can be used with all processes, throughout the software

development life cycle, and across different implementation
technologies

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

The Unified Modeling Language (UML) offers a standard way to
visualize a system's architectural blueprints, including elements
such as:
 activities
 actors
 business processes
 database schemas
 (logical) components
 programming language statements
 reusable software components

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

UML 2.0 defines thirteen types of diagrams, divided into THREE
categories: Six diagram types represent static application
structure; three represent general types of behavior; and four
represent different aspects of interactions:
 Structure Diagrams include the Class Diagram, Object Diagram,

Component Diagram, Composite Structure Diagram, Package
Diagram, and Deployment Diagram.

 Behavior Diagrams include the Use Case Diagram (used by

some methodologies during requirements gathering); Activity
Diagram, and State Machine Diagram.

 Interaction Diagrams, all derived from the more general

Behavior Diagram, include the Sequence Diagram,
Communication Diagram, Timing Diagram, and Interaction
Overview Diagram.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Diagram

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

UML 2 divided diagram types into two general sets:

1.

Structural Modeling Diagrams
Structure diagrams define the static architecture of a model. They are
used to model the 'things' that make up a model - the classes, objects,
interfaces and physical components. In addition, they are used to model
the relationships and dependencies between elements.

2.Behavioral Modeling Diagrams

Behavior diagrams capture the varieties of interaction and instantaneous
states within a model as it 'executes' over time; tracking how the system
will act in a real-world environment, and observing the effects of an
operation or event, including its results.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Structural Modeling Diagrams

Package diagrams are used to divide the model into logical
containers, or 'packages', and describe the interactions between them
at a high level.

Class diagrams define the basic building blocks of a model: the
types, classes and general materials used to construct a full model.

Object diagrams show how instances of structural elements are
related and used at run-time.

Composite Structure diagrams provide a means of layering an
element's structure and focusing on inner detail, construction and
relationships.

Component diagrams are used to model higher level or more complex
structures, usually built up from one or more classes, and providing a
well defined interface.

Deployment diagrams show the physical disposition of significant
artifacts within a real-world setting.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Package Diagrams

Package diagrams are used to reflect the organization of packages
and their elements. The most common use for package diagrams is
to organize use case diagrams and class diagrams, although the
use of package diagrams is not limited to these UML elements.

The following is an example of a package diagram.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Class Diagrams

The class diagram shows the building blocks of any object-
orientated system.

Class diagrams depict a static view of the model, or part of the
model, describing what attributes and behavior it has rather than
detailing the methods for achieving operations.

Class diagrams are most useful in illustrating relationships between
classes and interfaces.

Generalizations, aggregations, and associations are all valuable in
reflecting inheritance, composition or usage, and connections
respectively.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

The diagram illustrates aggregation relationships between classes. The lighter
aggregation indicates that the class "Account" uses AddressBook, but does
not necessarily contain an instance of it. The strong, composite aggregations
by the other connectors indicate ownership or containment of the source
classes by the target classes, for example Contact and ContactGroup values
will be contained in AddressBook.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Class Diagrams

Object Diagrams

An object diagram may be
considered a special case of a
class diagram.

Object diagrams use a subset of
the elements of a class diagram
in order to emphasize the
relationship between instances of
classes at some point in time.

They are useful in understanding
class diagrams. They don’t show
anything architecturally different
to class diagrams, but reflect
multiplicity and roles.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Component Diagrams

Component diagrams illustrate the
pieces of software, embedded
controllers, etc., that will make up a
system.

A component diagram has a higher
level of abstraction than a Class
Diagram - usually a component is
implemented by one or more
classes (or objects) at runtime.

They are building blocks so a
component can eventually
encompass a large portion of a
system.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Deployment Diagrams

A deployment diagram models the run-time architecture of a
system.

It shows the configuration of the hardware elements (nodes) and
shows how software elements and artifacts are mapped onto those
nodes.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Behavioral Modeling Diagrams

Use Case diagrams are used to model user/system interactions.
They define behavior, requirements and constraints in the form of
scripts or scenarios.

Activity diagrams have a wide number of uses, from defining basic
program flow, to capturing the decision points and actions within any
generalized process

State Machine diagrams are essential to understanding the instant to
instant condition, or "run state" of a model when it executes.

Communication diagrams show the network, and sequence, of
messages or communications between objects at run-time, during a
collaboration instance.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Behavioral Modeling Diagrams

Sequence diagrams are closely related to communication diagrams
and show the sequence of messages passed between objects using
a vertical timeline.

Timing diagrams fuse sequence and state diagrams to provide a view
of an object's state over time, and messages which modify that state.

Interaction Overview diagrams fuse activity and sequence diagrams
to allow interaction fragments to be easily combined with decision
points and flows.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Use Case Diagram

 Describe basic functions of the information system
 Describes activities that are performed by the users of the systems
 A set of scenarios that describing an interaction between a user and a

system.

 A use case diagram displays the relationship among actors and use

cases.

 The two main components of a use case diagram are use cases and

actors.

 An actor is represents a user or another system that will interact with

the system you are modeling. A use case is an external view of the
system that represents some action the user might perform in order to
complete a task.

When to Use: Use Case Diagram
 Use cases are used in almost every project. There are helpful in

exposing requirements and planning the project.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Example: Ordering System Use Case Diagram

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Activity Diagram

In UML, an activity diagram is used to
display the sequence of activities.

Activity diagrams show the workflow
from a start point to the finish point
detailing the many decision paths that
exist in the progression of events
contained in the activity.

They may be used to detail situations
where parallel processing may occur
in the execution of some activities.

Activity diagrams are useful for
business modeling where they are
used for detailing the processes
involved in business activities.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

State Machine Diagrams

A state machine diagram models the behavior of a single object,
specifying the sequence of events that an object goes through
during its lifetime in response to events.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Communication Diagrams

A communication diagram, formerly called a collaboration diagram, is an
interaction diagram that shows similar information to sequence diagrams but
its primary focus is on object relationships.

On communication diagrams, objects are shown with association connectors
between them. Messages are added to the associations and show as short
arrows pointing in the direction of the message flow. The sequence of
messages is shown through a numbering scheme.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Sequence Diagram

A sequence diagram is an interaction diagram that emphasizes the time
ordering of messages. It provides a sequential map of message passing
between objects over time.

Sequence diagrams are used to display the interaction between users,
screens, objects and entities within the system.

Frequently these diagrams are placed under Use Cases in the model to
illustrate the use case scenario - how a user will interact with the system and
what happens internally to get the work done.

A sequence diagram is a form of interaction diagram which shows objects as
lifelines running down the page, with their interactions over time represented
as messages drawn as arrows from the source lifeline to the target lifeline.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Sequence Diagrams

Sequence diagrams are good at showing which objects communicate
with which other objects; and what messages trigger those
communications. Sequence diagrams are not intended for showing
complex procedural logic.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Describe internal dynamic aspects of an info system that support
business processes in an organization.

During analysis phase, the behavioral models describe what the internal
logic of the processes is without specifying how the processes are to be
implemented.

In design and implementation phase, the detailed design of the
operations will be fully specified.

Creating behavioral model is an iterative process, not only iterates over
behavioral models, but also over functional and structural models.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Behaviour Model

Purpose of Behavioral Models
•

To depict the internal view of business processes

•

To show the effects of varied processes on the system

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Behaviour Model

Describe the structure of the data that supports the business
processes in organization.

During analysis phase, the structural model represents the logical
organization of data without indicating how the data are stored, created,
or manipulated so that system analysts can focus on the business
process without distracted by technical details.

In design phase, the model is updated to reflect exactly how the data
will be stored in databases and files.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Structural Model

Purpose of Structural Models

To show the static aspect of the system.

Reduce the “semantic gap” between the real world and the world of
software

Create a vocabulary for analysts and users (to communicate effectively)

Represent things, ideas, and concepts of importance in the application
domain

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Structural Model

Like a map, a model represents something else (some important
aspect of the real world)

A useful model has the right level of detail and represents only what is
important for the task in hand

Many things can be modelled: bridges, traffic flow, buildings,
economic policy

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

What is a Model?

A diagram illustrates some aspect of a system.

A diagram is a graphical representation of a set of elements in the
model of the system.

A model provides a complete view of a system at a particular stage
and from a particular perspective.

A model may consist of a single diagram, but most consist of many
related diagrams and supporting data and documentation.

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)

Diagram vs Model

Q&A

CONDUCT PRELIMINARY ANALYSIS

UNIFIED MODELING LANGUAGE (UML)