WXGE6102 Information Systems: Fundamentals, Procurement and Operational Issues

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WXGE6102 Information Systems Fundamentals,
Procurement and Operational Issues
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Lesson 4 The Role of System Analyst Succeeding
as a Systems Analyst

• Introduction Software Engineering Process
• Approaches to Systems Development
• Organizational Responsibilities in Systems
  Development
• Skills of a Successful Systems Analyst
• Analytical
• Technical
• Management
• Interpersonal

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Lesson 5

• Building Information System Methodologies,
  Models, Tools and techniques for System
  Development

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Today Topics

• Systems Development Life Cycle
• Major Problems Traditional SDLC
• Advantages and Disadvantages of Traditional SDLC
• Alternatives to Conventional SDLCs
• Prototyping
• Joint application design
• Rapid application development
• Object-oriented development
• Component Based development
• User development
• CASE Tools

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• Systems Analysis and Design is the process
  people use to create (automated) information
  systems

Systems Analysis Design
Information System
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SYSTEMS ANALYSIS AND DESIGN A Condensed
(Informal) Perspective
Completed Information System
An idea
Analysis
Design and Implementation
Time
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Today Topics

• Systems Development Life Cycle
• Major Problems Traditional SDLC
• Advantages and Disadvantages of Traditional SDLC
• Alternatives to Conventional SDLCs
• Prototyping
• Joint application design
• Rapid application development
• Object-oriented development
• Component Based development
• User development
• CASE Tools

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Systems Development Life Cycle

• Systems Development Life Cycle (SDLC) represents
  a set of general categories that show the major
  steps, over time, of an information systems
  development project.
• There is no universal, standardized version of
  the SDLC, but the phrase has two distinct
  meanings.
• An SDLC can be a general conceptual framework for
  all the activities involved in systems
  development or acquisition.
• An SDLC can also be a very structured and
  formalized design and development process.

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Systems Development Life Cycle (SDLC)

• Systems Investigation
• Systems Analysis
• Systems Design
• Systems Implementation
• Systems Evolution

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Systems Development Life Cycle

• Series of steps used to manage the phases of
  development for an information system
• Consists of five phases
• Investigation
• Project Identification and Selection
• Project Initiation and Planning
• Analysis
• Design
• Implementation
• Maintenance and review

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Phases of the Systems Development Life Cycle
Investigation

• Project Identification and Selection
• Two Main Activities
• Identification of need
• Prioritization and translation of need into a
  development schedule
• Helps organization to determine whether or not
  resources should be dedicated to a project.
• Project Initiation and Planning
• Two Activities
• Formal preliminary investigation of the problem
  at hand
• Presentation of reasons why system should or
  should not be developed by the organization

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Phases of the Systems Development Life Cycle
Analysis

• Study of current procedures and information
  systems
• Determine requirements
• Study current system
• Structure requirements and eliminate redundancies
• Generate alternative designs
• Compare alternatives
• Recommend best alternative

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Phases of the Systems Development Life Cycle
Design

• Logical Design
• Concentrates on business aspects of the system
• Physical Design
• Technical specifications
• Implementation
• Implementation
• Hardware and software installation
• Programming
• User Training
• Documentation

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Phases of the Systems Development Life Cycle

• Maintenance
• System changed to reflect changing conditions
• System obsolescence

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Today Topics

• Systems Development Life Cycle
• Major Problems Traditional SDLC
• Advantages and Disadvantages of Traditional SDLC
• Alternatives to Conventional SDLCs
• Prototyping
• Joint application design
• Rapid application development
• Object-oriented development
• Component Based development
• User development
• CASE Tools

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Major problems of traditional SDLC
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Major problems of traditional SDLC

• Many system projects fails, although they
  incorporates a formal SDLC approach.
• The environment is very different from 30 years
  ago.
• IT is much more powerful and includes features
  like graphical user interface and client server
  architecture
• Should abandon the SDLC?
• No ! Still very important.
• Incorporate alternative method.

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Today Topics

• Systems Development Life Cycle
• Major Problems Traditional SDLC
• Advantages and Disadvantages of Traditional SDLC
• Alternatives to Conventional SDLCs
• Prototyping
• Joint application design
• Rapid application development
• Object-oriented development
• Component Based development
• User development
• CASE Tools

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Advantages and Disadvantages of Traditional SDLC
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Today Topics

• Systems Development Life Cycle
• Major Problems Traditional SDLC
• Advantages and Disadvantages of Traditional SDLC
• Alternatives to Conventional SDLCs
• Prototyping
• Joint application design
• Rapid application development
• Object-oriented development
• Component Based development
• User development
• CASE Tools

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Alternatives to Conventional SDLCs

• Possibilities
• Prototyping
• Joint application design
• Rapid application development
• Object-oriented development
• Component Based development
• User development

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Prototyping

• Instead of spending a lot of time producing very
  detailed specifications, the developers find out
  only what the users want.
• Developers quickly create a prototype.
• This contains portions of the system of most
  interest to the users, or is a small-scale
  working model of the entire system.
• After reviewing the prototype with the users, the
  developers refine extend it.
• This approach is also known as evolutionary
  development.

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Waterfall Model with Prototyping
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Joint Application Design

• Joint application design (JAD) is a group-based
  method for collecting user requirements and
  creating system designs.
• JAD is most often used within the systems
  analysis and systems design stages of the SDLC.
• In contrast to the SDLC requirements analysis,
  JAD has a group meeting in which all users meet
  simultaneously with analysts.
• Users, Managers and Analysts work together for
  several days
• System requirements are reviewed
• Structured meetings
• An electronic JAD session can be conducted
  offsite/online with technology support.
• JAD may not be an easy task for Web site design
  since in some cases the stakeholders may be
  outside of an organization.

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Rapid Application Development

• Rapid application development (RAD) methodologies
  and tools make it possible to develop systems
  faster, especially systems where the user
  interface is an important component.
• Rapid Application Development (RAD)
• Utilizes prototyping to delay producing system
  design until after user requirements are clear

• Typical RAD packages include the following
• GUI development environment
• Reusable components
• Code generator
• Programming language

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Rapid Application Development (cont.)
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Object-Oriented Development

• An object-oriented (OO) system begins not with
  the task to be performed, but with the aspects of
  the real world that must be modeled to perform
  that task.
• Object technology enables the development of
  purchasable, sharable, and reusable information
  assets (objects) existing in a worldwide network
  of interorganizational information systems.
• The techniques and notations that are
  incorporated into a standard object-oriented
  language are called unified modeling language or
  UML.
• The object-oriented approach is ideal for
  developing Web applications.

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Component-based Development

• Components are self-contained packages of
  functionality that have clearly defined, open
  interfaces with high-level application services.
• E.g., interface icons (small), online ordering (a
  business component)
• Components can be distributed dynamically for
  reuse across multiple applications and
  heterogeneous computing platforms.
• The major reasons for using components-based
  development are
• Code reusability, which make programming faster,
  with fewer errors.
• Support for heterogeneous computing
  infrastructure and platforms.
• Rapid assembly of new business applications
• Ability of an application to scale.

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End User Development

• Many organizations are using approaches that
  shift the construction task from the IS
  department to others.
• Of the various ways of doing this, three are most
  common
• Let users build their own systems
• Outsource the entire systems development process
• Let end-users and/or the ISD use packages

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Outsourcing

• The purchase of any product or service from
  another company.
• Companies outsource the product or service they
  unable or unwilling to produce themselves
• Can provide IT services at 10-40 lower cost,
  with higher quality

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Alternatives to Conventional SDLCs

• Possibilities
• Prototyping
• Joint application design
• Rapid application development
• Object-oriented development
• Component Based development
• User development

Limitation
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Limitations

• The traditional SDLC approach often works well
  for large projects with well-defined
  requirements, where there is not a lot of time
  pressure.
• Prototyping requires effective management to make
  sure that the iterations of prototyping do not
  continue indefinitely.
• RAD may be less appropriate than conventional
  programming languages for larger projects, or
  those with a lot of real-time processing.
• JAD is easy for senior management to understand,
  yet it is difficult and expensive to get all
  people in the same place at the same time.

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Limitations (cont.)

• Object-Oriented development is becoming
  increasingly popular, but usage is limited by a
  shortage of personnel with OO skills. (UML)
• A component-based application architecture
  provides several business benefits, but the
  execution of component-based development requires
  special training and skill. (SAP, SET)
• End-user development is also a possibility for
  larger projects whose priorities are not high
  enough to lead to a timely response from the
  central IS unit.
• Outsourcing should always be considered by large
  and complex systems with a significant risk of
  failure, yet the disadvantages should be reviewed
  carefully.

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CASE Tools

• Computer-aided software engineering (CASE) tools
  are marketed as individual items or in a set
  (toolkit) that automates various aspects of the
  development process.
• CASE can be used in two different ways
• To automate certain SDLC activities on a
  piecemeal/different basis.
• To provide an integrated (I-CASE) package for IS
  groups.
• Some typical CASE tools are
• Code generation tools
• Code generation is the process by which a
  compiler converts a syntactically-correct program
  into a series of instructions that could be
  executed by a machine
• Unified Modeling Language (UML) editors
• Refactoring tools
• Refactoring is the process of rewriting a
  computer program or other material to improve its
  structure or readability, while explicitly
  keeping its meaning or behavior.
• Disadvantages
• The relatively high turnover rate among systems
  personnel creates problems for use of I-CASE
  systems as new employees will need to take the
  time to learn the integrated package.

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Question To Ponder

• Explain in detail each phase of SDLC.
• Discuss the alternative methodologies to
  conventional SDLC and their limitation

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Next Lecture
Lesson 6 Systems Investigation and Analysis
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Thank You
Q A