system analysis and design rabie a. ramadan, phd 2 30/3/2011

System Analysis and Design

Rabie A. Ramadan, PhDhttp://rabieramadan.org

2

30/3/2011

SYSTEM DEVELOPMENT METHODOLOGIES

1 - 2

Rapid Application Development (RAD)

1 - 3

Incorporate special techniques and tools:• CASE tools

• JAD sessions

• Fourth generation/visualization programming languages

• Code generators

CASE tools

1 - 4

Computer-aided software engineering (CASE)• Scientific application of a set of tools

and methods to a software system which is meant to result in high-quality, defect-free, and maintainable software products.

Modeling business / real-world processes and data flow.

Development of data models in the form of entity-relationship diagrams

JAD sessions

1 - 5

Joint Application Development (JAD)

• Developed by Drake and Josh of IBM

• IBM Toronto in a workshop setting.

• JAD was designed to bring system developers and users of

varying backgrounds and opinions together in a productive

as well as creative environment.

Three RAD Categories

1 - 6

Phased development• A series of versions developed sequentially

Prototyping• System prototyping

Throw-away prototyping• Design prototyping

Phased Development Methodology

1 - 7

Insert Figure 1-4 here

Pros and Cons of Phased Development Methodology

1 - 8

Pros Cons

Users Get a SystemTo Use Quickly

Users Can IdentifyAdditional NeedsFor Later Versions

Users Work with aSystem that isIntentionally Incomplete

How Prototyping Works

1 - 9

Pros and Cons of Prototyping Methodology

1 - 10

Pros Cons

Users Interact withPrototype Very Quickly

Users Can IdentifyNeeded ChangesAnd Refine RealRequirements

Tendency to doSuperficial Analysis

Initial Design Decisions May

Be Poor

Throwaway Prototyping

1 - 11

Pros and Cons of Throwaway Prototyping Methodology

1 - 12

Pros Cons

Risks are Minimized

Important Issues areUnderstood Before the

Real System is Built

May Take LongerThan Prototyping

Agile Development: Extreme Programming

1 - 13

Pros and Cons of Agile Methodologies

1 - 14

Pros Cons

Fast Delivery of Results

Works Well in ProjectsWith Undefined or

Changing Requirements

Requires Discipline

Works Best in Small Projects

Requires MuchUser Input

Criteria for Selecting the Appropriate Methodology

1 - 15

Clear user requirements Familiarity with technology Complexity of system Reliability of system Time schedule Schedule visibility

TEAM ROLES AND SKILLS

1 - 16

Information Systems Roles

1 - 17

Business analyst Systems analyst Infrastructure analyst Change management analyst Project manager

1 - 18

Summary

1 - 19

The Systems Development Lifecycle consists of four stages: Planning, Analysis, Design, and Implementation

There are six major development methodologies: the waterfall method, the parallel development method, the phased development method, system prototyping, design prototyping, and agile development.

There are five major team roles: business analyst, systems analyst, infrastructure analyst, change management analyst and project manager.

20

Project Initiation

Key Ideas

2 - 21

An opportunity to create business value from using information technology initiates a project.

Feasibility analysis helps determine whether or not to proceed with the IS project.

Projects are selected based on business needs and project risks.

Key Ideas

2 - 22

The project sponsor is a key person who identifies business value to be gained from using information technology.

The approval committee reviews system requests from groups throughout the organization and selects projects for the benefit of the business.

Why a new system?

2 - 23

Problem Orientation

• Define the problem

• Establish system objectives

• Identify the USERS

• Establish functional scope

IDENTIFYING PROJECTS WITH BUSINESS VALUE

2 - 24

Why Implement a new system?

2 - 25

Capability

Communication

Control

Cost

Competitive advantage

Why Implement a new system?

2 - 26

• Capability: EfficiencyCapability: Efficiency• improve processing speed

• ability to handle increased volume

• PC vs. manual methods, more PC's, LAN

• faster retrieval of information

• Bigger, faster data storage, SQL-based DBMS Canned-software (Order entry, Manufacturing, etc.)

Why Implement a new system?

2 - 27

• Control: Efficiency/Effectiveness• Improved accuracy and consistency

• automating the process to reduce human error

• Computer prompting, error detection, field value checks

• Provide better security

• Need to know screens

• Password protection

Why Implement a new system?

2 - 28

• Communication: Effectiveness

• Enhance communication

• Credit card systems, E-Mail

• Integration of business areas: Coordination

• LAN communication, Manufacturing systems

Why Implement a new system?

2 - 29

• Cost: Effectiveness

• Monitor Costs

• Tracking cost through a system (manufacturing LED-CS)

• Reducing costs

• automatic calculation-retrieval systems

Why Implement a new system?

2 - 30

• Competitive Advantage: Effectiveness: a strategic weapon

• Lock in customers

• by offering a better price

• by providing a unique service

• by presenting distinctive products

• Lock out competitors

• Improve arrangement with suppliers

Preliminary Project Acceptance

System request is reviewed by approval committee

Based on information provided, project merits/values are assessed.

Worthy projects are accepted and undergo additional investigation – the feasibility analysis.

How Do Projects Begin?

Business needs should drive projects.

Project sponsor recognizes business need for new system and desires to see it implemented.

Business needs determine the system’s functionality (what it will do).

The project’s business value should be clear.

System Request

A document describing business reasons for project and system’s expected value.

Lists project’s key elements• Project sponsor

• Business need

• Business requirements

• Business value

• Special issues or constraints

System Request Examples Project sponsor – Carrefour of Marketing

Business need – Reach new customers and improve service to existing customers

Business requirements – Provide web-based shopping capability

Business value - $750,000 in new customer sales; $1.8M in existing customer sales

Special issues or constraints – System must be operational by holiday shopping season

Your Turn

2 - 35

If you were building a web-based system for course registration,• What is the business need?

• Reach new and make easy on them to register

• What would be the business requirements?• Computer System and Internet

• What would be the business value (tangible and intangible)?• Tangible: new students , intangible: raise the rank of the univ.

• What special issues or constraints would you foresee?• Expanding the IT department , maintenance , new budget

FEASIBILITY ANALYSIS

2 - 36

Feasibility Analysis

2 - 37

Detailed business case for the project• Technical feasibility

• Economic feasibility

• Organizational feasibility

Compiled into a feasibility study

Feasibility is reassessed throughout the project

Technical Feasibility:Can We Build It?

Users’ and analysts’ familiarity with the business application area

Familiarity with technology

• Have we used it before? How new is it? Project size

• Number of people, time, and features Compatibility with existing systems

Can we build it?

2 - 39

• Feasibility• Technical

• Do we have the capability to develop the system?

• Does the necessary tech exist? Can it be acquired?

• Does the proposed equipment have the right capacity for the data?

• Does the propose have the right: response time, interface,

• Can the system be expanded?

• Are the accuracy, reliability, ease of use, ease of access, security ok?

Economic FeasibilityShould We Build It?

Identify costs and benefits Assign values to costs and benefits Determine cash flow Assess financial viability

• Net present value

• Return on investment

• Assess Financial Viability

Should we build it?

2 - 41

•Economic

•Is there an economic payoff?

•include cost to conduct full systems integration

•cost of hardware/software/ other

•benefits in terms of reduced costs

•opportunity costs

Assign Cost and Benefit Values

Difficult, but essential to estimate

Work with people who are most familiar with the area to develop estimates

Intangibles should also be quantified

If intangibles cannot be quantified, list and include as part of supporting material

Identify Costs and Benefits

2 - 43

Costs Benefits

Tangible

Intangible

***

***

***

***

Determine Cash Flow

Assess Financial Viability – Net Present Value (NPV)

NPV = PV(future cash inflows) –

PV(future cash outflows)

PV = Cash flow amount

(1 + interest rate)n , where• interest rate = required return

• n = number of years in future

Determine NPV

If NPV >= 0,

Project is OK

If NPV < 0,

Project is unacceptable

Assess Financial Viability – Return on Investment

ROI = NPV PV(cash outflows)

Assess Financial Viability – Break Even Point

How long before the project’s returns match the amount invested

The longer it takes to break even, the higher the project’s risk.

Organizational FeasibilityIf we build it, will they come?

Strategic alignment• How well do the project goals align with business

objectives?

Stakeholder analysis• Project champion(s)

• Organizational management

• System users

Why a new system?

2 - 50

Organizational

• Is there support/resistance; from or by who

• Are current business methods acceptable?

• If not a change may be welcomed

• Have the user's been involved? If not get them involved

• Will the system cause harm?

What is Expected?

2 - 51

• The EXPECTED RESULTS

• SATISFIES the organizations requirements

• operates RELIABLY

• creates an "appropriate" working environment

• is MAINTAINABLE

• is MODIFIABLE

• is ADAPTABLE to a changing environment

• has controls to ensure:• security

• privacy

• audibility -

What is expected

2 - 52

A. Objectives of System Analysis

• To establish in detail what the systems is to do• objectives

• costs

• benefits

• implementation process

• organizational changes required

• INNOVATION

• defines who the USERS are

• Their input and output

• THE SYSTEM FLOW

Why a new system?

2 - 53

• Alternative Specification• Propose options

• Make versus buy decisions

• Cost-Benefit analysis

• Assess project risk

• Recommend

• Unwritten- find allies

PROJECT SELECTION

2 - 54

Project Selection Issues

Approval committee works from the system request and the feasibility study• Project portfolio – how does the project fit within the

entire portfolio of projects?

• Trade-offs must be made to select projects that will form a balanced project portfolio

• Viable projects may be rejected or deferred because of project portfolio issues.

Summary

2 - 56

Project initiation involves creating and assessing goals and expectations for a new system

Identifying the business value of the new project is a key to success

Feasibility study is concerned with insuring that technical, economic, and organizational benefits outweigh costs and risks

Project selection involves viewing the project within the context of the entire project portfolio, and selecting those projects that contribute to balance in the portfolio

Your Project During the Semester

2 - 57

Step 1:

• Since you are here at Future University , Define the needed projects for the University and asses their feasibility.

• Write a complete proposal by the next week in a doc file

• I will asses your proposals and approve one