System Analysis and Design

1. System Analysis and
Design:
System Analysis Approaches
Shikuku S.
Eric Munyiri
Vitalis Odinga

2. System Analysis
Systems analysis defines the problems to be solved
and provides the architecture of the proposed
system.
The terms analysis and synthesis come from Greek
where they mean respectively "to take apart" and "to
put together".
Analysis is defined as the procedure by which we
break down an intellectual or substantial whole into
parts.
Synthesis is defined as the procedure by which we
combine separate elements or components in order
to form a coherent whole.

3. System Analysis
 System analysis is an explicit formal inquiry
carried out to help a decision maker identify a
better course of action and make a better
decision than he might otherwise have made.
 Systems analysis is a problem-solving
technique that decomposes a system into its
component pieces for the purpose of studying
how well those component parts work and
interact to accomplish their purpose.

4. System Analysis
 This is a process used in the design of new
systems. Systems analysis follows stages of
investigation, design and implementation.
 Each stage should involve close consultation
with potential users, in the various functional
areas of the organisation, to ensure that their
information and operational requirements are
met.

5. When to use system analysis and design
 To correct problem in existing system
 To improve existing system
 Usher in a new system
 Outside group may mandate change
 Competition can lead to change

6. System Project Overview
 Scope Definition
Is the project worth looking at?
 Problem Analysis
Is a new system worth building?
 Requirements Analysis
What do the users need and want from the new
system?
 Logical Design
What must the new system do?
 Decision Analysis
What is the best solution?

8. SWOT Analysis for System Project
Possible IT Strengths
- Excellent Web design staff
- Low systems analyst turnover
- Recently upgraded network
Possible IT Weaknesses
- Still using several legacy systems
- Budget increase was turned down
- Documentation needs updating
Possible IT Opportunities
- Well-position for expansion
- Can be first with new software
- High potential for B2B growth
Possible IT Threats
- Aggressive new Web competition
- Impact of new government rules
- Other firms offer better benefits

9. System Analysis Techniques
Logical data modeling
This is the process of identifying, modeling and documenting the data
requirements of the system being designed. The data are separated
into entities (things about which a business needs to record
information) and relationships (the associations between the entities).
Data Flow Modeling
This is the process of identifying, modeling and documenting how data
moves around an information system. Data Flow Modeling examines
processes (activities that transform data from one form to another),
data stores (the holding areas for data), external entities (what sends
data into a system or receives data from a system), and data flows
(routes by which data can flow).
Entity Behavior Modeling
This is the process of identifying, modeling and documenting the events
that affect each entity and the sequence in which these events occur.

10. Reasons for systems projects
 Improved service
 Better performance
 More information
 Stronger controls
 Reduced cost

11. Factors that affect systems projects
 Internal Factors
 Strategic plan
 Top managers
 User requests
 Information technology
department
 Existing systems
 External Factors
 Technology
 Supplier
 Customers
 Technology
 Competitors
 The economy
 Government

12. Systems Development Life Cycle
Feasibility Study
Measure of how suitable
system development will
be to the company
Technical
feasibility
Economic
feasibility
(cost-benefit
analysis)
Schedule
(Time)
feasibility
Operational
feasibility
The
four
feasibility
tests

13. Participants

14. Systems Development Life Cycle
(SDLC)
 The SDLC in system analysis and design
aims to produce a high quality system that
meets or exceeds customer expectations,
reaches completion within time and cost
estimates, works effectively and efficiently
in the current and planned Information
Technology infrastructure, and is inexpensive
to maintain and cost-effective to enhance.

15. Systems Development Life Cycle (SDLC)

16. Systems Development Life Cycle
Phase 1. Planning
Review project requests
Prioritize project requests
Allocate resources
Identify project development team
Identifying business value
Analyze feasibility
Develop work plan
Staff the project
Control and direct project

17. Systems Development Life Cycle
Phase 2. Analysis
 Conduct preliminary investigation.
 Determine exact nature of problem or improvement and whether
it is worth pursuing.
 Findings are presented in feasibility report (feasibility study)
 Perform detailed analysis activities:
 Study current system
 Determine user requirements
 Recommend solution
 Analysis strategy
 Gathering business requirements
 Requirements definition
 Process modeling
 Data modeling

18. Systems Development Life Cycle
Phase 3. Design
 Assesses feasibility of each alternative solution
 How system will be developed
 Recommends the most feasible solution
 Design selection
 Architecture design
 Interface design
 Data storage design
 Program design

19. Systems Development Life Cycle
Phase 4. Implementation
 Construction
 Program building Develop programs
 Install and test new system
 Program and system testing
 Installation
 Conversion strategy
 Training plan
 Convert to new system
 Support plan

20. Systems Development Life Cycle
Phase 5. Support and Maintenance
 Conduct post-implementation system review
 Identify errors and enhancements
 Monitor system performance

21. Requirements Analysis
Information Discovery
The process of collecting information about
system problems, opportunities, solution
requirements, and priorities

22. Information Discovery
 Review and sampling of existing
documentation, reports, forms, databases, etc
 Interview
 Joint-application design (JAD) session
 Joint requirement planning (JRP)
 Research of relevant literature
 Observation of the current system
 Questionnaires and surveys

23. Product Information Discovery
 References from vendor
 Talk to current users of product
 Product demonstrations
 Trial version of software
 Benchmark test measures performance

24. Information Discovery
Joint requirements planning (JRP)
The use of facilitated workshops to bring together all of
the system owners, users, and analysts, and some
systems designer and builders to jointly perform
systems analysis.
JRP is generally considered a part of a larger method
called joint application development (JAD), a more
comprehensive application of the JRP techniques to
the entire systems development process.

25. Benefits of JRP/JAD
 Saves Time: It reduces the number of interviews
needed to gather the requirements and reduces
discrepancies. Everyone is in the room.
 Saves Money: Fewer change requests, eliminates re
works.
 Increased user buy in: users participation creates
ownership of the system.
 Better Requirements Documentation:
 Higher Customer Satisfaction: Customer knows at
what stage the product is. The system meets
customer needs.

26. Systems Development Life Cycle
Strengths
 Control.
 Monitor large projects.
 Detailed steps.
 Evaluate costs and completion
targets.
 Documentation.
 Well defined user input.
 Ease of maintenance.
 Development and design
standards.
 Tolerates changes in MIS
staffing.
Weaknesses
 Increased development time.
 Increased development cost.
 Systems must be defined up front.
 Rigidity.
 Hard to estimate costs, project
overruns.
 User input is sometimes limited.

27. System Analysis Methodologies
 Lifecycle/waterfall approach,
 CASE tools,
 Prototype,
 RAD/RSD,
 JAD,
 Object-oriented methodology.

28. Waterfall

29. Waterfall
 A sequence of stages in which the output of each stage
becomes the input for the next.
 In the waterfall model, it is possible to rework earlier
stages in the light of experience gained at a later
stage. Each stage is signed off and the next stage is
proceeded with. However the end user is rarely
involved in the development stage, even though they
may well be involved in signing off.
 It is therefore critical that the analysts and the
programmers understand the end-users’ requirements.
 This can be quite difficult with the waterfall model.

30. Waterfall Benefits
 Misunderstandings are detected at early stages
 Identifies systems requirements long before
programming begins
 The user will notice any missing functions, incomplete
or inconsistent requirements.
 Minimizes changes to requirements as project
progresses.
 Can be built quickly to demonstrate systems
 It can be used for training before the system is finished

31. Waterfall Shortcoming
 Design must be specified on paper before
programming begins
 Long time between system proposal and delivery of
new system
 The waterfall model has disadvantages, which can be
overcome using Prototyping, in which a model of the
system is developed in partnership with the end-user.
 The features are worked out with the end user using
a prototype, and the end user can have a
considerable input into the development of a project.

32. Rapid Application Development (RAD)
Utilizes prototyping to delay producing system
design until after user requirements are clear
 Phased development
 A series of versions developed sequentially
 Prototyping
 System prototyping
 Throw-away prototyping
 Design prototyping

33. Phased Development

34. Prototyping
 A small-scale, incomplete, but working sample of a desired
system.
 Working model of proposed system
 Building a scaled-down working version of the system
 Advantages:
 Users are involved in design
 Captures requirements in concrete form

35. Prototyping

36. Prototyping

37. Prototyping
Benefits
 Users interact with prototype very quickly
 Users can identify needed changes and
refine real requirements
Shortcoming
 Tendency to do superficial analysis
 Initial design decisions may be poor

38. Throwaway Prototyping

39. Throwaway Prototyping
Benefits
 Risks are minimized
 Important issues are understood before
the real system is built
Shortcoming
 May take longer than prototyping

40. Joint Application Design (JAD)
 Users, Managers and Analysts work together
for several days
 System requirements are reviewed
 Structured meetings

41. Agile method
 The integration of various approaches of
systems analysis and design for applications
as deemed appropriate to the problem being
solved and the system being developed.

42. Agile

43. Agile
Benefits
 Fast delivery of results
 Works well in projects with undefined or
changing requirements
Shortcoming
 Requires discipline
 Works best in small projects
 Requires much user input

44. Selecting the Appropriate Methodology
 Clear user requirements
 Familiarity with technology
 Complexity of system
 Reliability of system
 Time schedule
 Schedule visibility

45. References
1. Systems development life-cycle. From Wikipedia, the free encyclopedia.
http://en.wikipedia.org/wiki/Systems_development_life-cycle
2. Project management. From Wikipedia, the free encyclopedia.
http://en.wikipedia.org/wiki/Project_life_cycle#Project_development_stages
3. Boehm, B. W. (1988). A Spiral Model of Software Development and
Enhancement, Computer, May
4. DeMarco, T. (1978). Structured Analysis and System Specification, Prentice-
Hall
5. Systems Analysis and Design, by Wiley