Chapter 5
System Analysis
Sarah El Sehemawy
Karim Elsabee
Sherine Meshad
Hakim Meshriky
Ahmed Zaki
Ismail Abou Hamda
System Analysis
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System Analysis
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It is a problem solving technique that decomposes
a system into component pieces for the purpose
of studying how well those components work and
interact to accomplish their purpose.
It primarily focuses on the business view,
independent of any technology.
System Design
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It is a complementary problem solving technique
to system analysis that reassembles a system’s
components pieces back into a complete system –
hopefully an improved system. This may involve
adding, deleting and changing pieces relative to
the original system.
System Analysis Approaches
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Model-Driven Analysis Approaches
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Structured Analysis
Information Engineering
Object-Oriented Analysis
Accelerated Analysis Approaches
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Discovery Prototyping
Reverse Engineering
Model-Driven Analysis Approach
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Structured Analysis
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Information Engineering (IE)
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Definition: It is a model-Driven, Process-centered technique used to analyze an
existing system, and propose a new one. Processes are the primary focus of
that system model. Data and interface are also modeled.
Output: Process models called Data Flow Diagrams (DFDs)
Definition: Also model-Driven, but Data-centered. It intends to synchronize the
system’s data, and then processes. It is data centered because it focuses on the
data requirements of the system.
Output: Data model called Entity Relationship Diagram (ERD).
The two previous approaches differ only in the order of drawing the DFD, and
the ERD.
Object-Oriented Analysis (OOA)
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Definition: It is a model-driven technique that integrates Data and Processes
concerns into constructs called Objects. OOA modes are pictures that illustrate
the system’s objects.
Output: Unified Modeling Language (UML) depicts the OOA models.
Difference: No Database. Data and Processes are stored physically on the same
layer.
Accelerated Analysis Approaches
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Definition: Accelerated approaches emphasize the
construction of prototypes to more rapidly identify
the business and user requirements for a new
system.
Prototype: Small-Scale, incomplete, but working
sample of a desired system.
Types:
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Discovery Prototyping: Identifies user’s business
requirements by having to react to a quick implementation.
Reverse Engineering: Reads the program code for an
existing database, program, and automatically generates
system model, which is edited, and improved.
Project Phases
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Preliminary Investigation Phase
Problem Analysis Phase
Requirement Analysis Phase
Decision Analysis Phase
Design Phase
Construction Phase
Implementation Phase
Operation and Support Phase
Preliminary Investigation –
Phase 1
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The Preliminary Investigation phase
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First phase of the classic systems development
process.
Answers the question: “Is the project worth
looking at?”.
It is intended to be quick & should not
exceed 2 or 3days for most projects.
Most of the tasks in this phase are led by a
senior systems analyst or a project manager
and include system owners as participants.
Phase 1 - Preliminary
Investigation Con’t
Preliminary Investigation Consists of the
following 5 steps:
1.
List problems ,opportunities and
directives
2.
Negotiate preliminary scope
3.
Assess project worth
4.
Plan the project
5.
Present the project and plan
Phase 1 - Preliminary Investigation
Con’t
1. List problems, opportunities and directives:
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Each problem, opportunity or directive is assessed
with respect to urgency, visibility, benefits and
priority.
The key deliverable of this task is a preliminary
problem statement.
Primary techniques include fact-finding & meeting
with system owners.
Phase 1 - Preliminary Investigation
Con’t
2. Negotiate preliminary scope:
 Scope defines the boundary of the project.
 A project’s scope can be described in terms of:
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What types of data describe the system being studied?
What business processes are included in the system being
studied?
How must the system interface with users, locations and
other systems?
This task deliverable is the preliminary problem statement
with scope.
Primary techniques to accomplish this task are also factfinding &meetings.
Phase 1 - Preliminary Investigation
Con’t
3. Assess project worth
This is where we answer the question:
 “ Will the development of the new system
return enough value to offset the costs
incurred?”
 There is no physical deliverable than the go
or no-go decision.
 The remaining tasks are necessary only if the
project is approved.
Phase 1 - Preliminary Investigation
Con’t
4. Plan the project:
 An initial project plan should consist of at
least the following:
 A preliminary master plan that includes
schedule and resource assignments for the
entire project.
 A detailed plan and schedule for completing
the next phase of the project.
 The deliverable of this task is the project
plan.
Phase 1 - Preliminary Investigation
Con’t
5. Present the project and plan:
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Unless the project is predetermined to be of the highest priority,
it must be presented to a steering body for approval.
A steering body is a committee of executive business and
system managers that studies and prioritize project proposals to
determine which projects should be approved or continued.
Deliverable of this task is the project charter, which is usually a
document.
The project charter defines the project in terms of participants,
problems, opportunities and directives; methodology; statement
of work to be completed; deliverables; quality standards and
budget.
If approved, the project can now proceed to the problem
analysis phase.
Phase 2 : Problem Analysis Phase
Answers the questions :
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Are the problems really worth solving?
Is a new system really worth building?
Goal:
Study and understand the problem domain well enough
to thoroughly analyze its problems, opportunities and
constraints.
Final Deliverables :
Produce System Improvement Objectives that address
problems , opportunities and directives
“ Don’t try to fix it , unless you understand it!”
The Problem Analysis Phase (6 Steps)
Study the problem domain
Learn about the current system in which the bus problems
opportunities, directives and constraints exist.
Analyze Problems and Opportunities
Learn to truly analyze a problem before stating any
possible solutions
Analyze each perceived problem for cause and effect
Analyze Business Processes (Optional)
Appropriate only to business process redesign
examine business process to measure value added or
subtracted by each process as it relates to the total organization
The Problem Analysis Phase (6 Steps)
Establish System Improvement Objectives
Establish the criteria against which any improvement to the
system will be measured and identifies any constraints that
may limit flexibility in achieving these improvements.
Update The Project Plan
Reevaluating scope and update the project plan accordingly
Present findings and recommendations
Appropriate elements are combined into system
improvement objectives , presented in a report or a
verbal presentation
Conclusion :
Continue , adjust or cancel the project
Phase 3:Requirement Analysis Phase
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This phase defines the Business Requirements for a new system
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What do the users need and want from a new system? WHAT NOT HOW!
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The Requirement Analysis Phase includes the following tasks:
1- Define Requirements
2- Analyze Functional Requirements
3- Trace and Complete Requirements
4- Prioritize Requirements
5- Update the Project Plan
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Define Requirements:
This task translate the system improvements objectives (established in the
problem analysis phase) into an outline of Functional and Nonfunctional
requirements that will be needed to meet the objectives
Phase 3:Requirement Analysis Phase
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Analyze Functional Requirements:
Functional Requirements are analyzed such that they can be verified
and communicated to both:
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Users so they can prioritize the needs and justify the expenses
Designers so they can transform them into appropriate technical solutions.
There are 2 approaches to functional requirements documentation and
validation SYSTEM MODELING & PROTOTYPING.
Requirements are analyzed for accuracy, urgency, consistency, flexibility
and feasibility.
Trace and Complete Requirements:
Tracing each system model and/or prototype back to the functional
requirement that it fulfills and ensuring that all functional requirements
are included in the system models or prototype.
Phase 3:Requirement Analysis Phase
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Prioritize Requirements:
System Owners and Users should prioritize business because it may be
useful to recognize which requirements are more important than
others if a project gets behind schedule or over budget.
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Prioritization of business requirements enable TIMEBOXING, which is a
technique that delivers system functionality and requirements through
versioning.
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All DESIRABLE REQUIRMENTS are included following version according
to there ranking.
Update the Project Plan:
Scope
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All MANDATORY REQURMENTS are included in Version 1.0 (the System
is useless without it)
Schedule
Budget
Output of this phase is a business requirements statement.
Project Phase 4:
Decision Analysis Phase
Business
requirements
DECISION
ANALYSIS
PHASE
System
Proposal
Project Phase 4:
Decision Analysis Phase
The decision analysis phase includes 5
tasks as follows
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1.
Identify Candidate Solutions
(Sources :System Owners, Users, analysists , Desginers, technical
consultants……)
2.
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Analyze Candidate Solution (Feasibility)
Operational
Economic
Schedule
Technical (done by system designers and builders)
Project Phase 4:
Decision Analysis Phase
3.
Compare Candidate Solutions
(Feasibility analysis Matrix)
Feasibility criteria
Weight
Candidate
1
Candidate
2
Candidate3
%
%
%
1.Operational
2.Technical
3.Economic
4.Schedule
Ranking
100%
Project Phase 4:
Decision Analysis Phase
4.
Update the project plan
5.
Recommend a solution
Cross Life Cycle Activities
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Cross life cycle activities are activities that overlap many or all
phases of the methodology.
Fact Finding
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Formal process of using research, interviews,
meetings, questionnaires, sampling.
Also Called data collection.
Documentation and Presentations
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Activity of recording facts and specifications for a
system for current and future reference.
Communicating Findings, recommendations, and
documentation for review by interested managers
Cross Life Cycle Activities
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Feasibility Analysis
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Continuous Analysis of the development of
the IS.
Project Management
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Defining, planning, directing, monitoring,
and controlling a project to develop an
acceptable system within the specified
time, and budget.