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Chapter 14. Building Information Systems. Information System Components. A system is a set of related components that produce specified results, from launching the space shuttle to operating your microwave oven, information systems are everywhere.

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chapter 14

Chapter 14

Building Information Systems

information system components
Information System Components
  • A system is a set of related components that produce specified results, from launching the space shuttle to operating your microwave oven, information systems are everywhere.
  • For any organization, information systems perform different functions of varying importance.
  • An information system that is required for an organization to operate is called a mission-critical system.
information system components1
Information System Components

Software

Hardware

Processes

People

Data

information system components2
Information System Components
  • Data: Data is raw input that will, ideally, be turned into useful information.
  • Processes: Are the procedures by which data is converted into information.
  • Software: The application programs that enable the performance of operations required by the processes.
  • Hardware: The physical computing equipment needed by the organization to complete the processes on a sufficient scale.
  • People: The end users, they include everyone from the data entry clerk to the CEO, who will interact with the system
types of information systems
Types of Information Systems
  • Information Systems are categorized as:
      • Transaction Processing Systems
      • Management Information Systems
      • Decision Support Systems
      • Executive Information Systems
  • All of the above systems use, essentially the same data, but involve very different processes
  • Determining which type of system you need is done during systems analysis and design
systems development life cycle
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 generalconceptualframework for all the activities involved in systems development or acquisition.
    • An SDLC can also be a very structured and formalized design and development process.
stages 1 2
Stages 1 & 2
  • Stage 1: Project Initiation
  • Stage 2: Systems Analysis & Feasibility Studies
    • Systems Analysis- the investigation of the existing situation.
    • Feasibility Studies- the major areas of feasibility investigation are;
      • Technology
      • Economics
      • Organizational factors
      • Legal, ethical, and other constraints
stages 3 4
Stages 3 & 4
  • Stage 3: Logical Analysis and Design
    • Systems analysts determine 2 major aspects of the system:
      • what it needs to do
      • how it will accomplish these functions.
    • Logical Design – the design of an IS from the user’s point of view.
    • Physical Design -translates the abstract logical model into the specific technical design (the “blueprints”)
  • Stage 4: Actual Acquisition or Development
    • The logical design of the new system guides the actual development or acquisition
stages 5 6
Stages 5 & 6
  • Stage 5: Implementation
    • Approaches to conversion from a previous system include:
      • Parallel conversion
      • Direct cutover
      • Pilot conversion
      • Phased (or modular) conversion
  • Stage 6: Operation
    • After a successful conversion, the system will operate for an indefinite period of time.
stages 7 8
Stages 7 & 8
  • Stage 7: Post-audit Evaluation
    • An organization should evaluate all its larger system projects after their completion.
    • These post-audits introduce an additional element of discipline into the development process.
  • Stage 8: Maintenance
    • Every system needs two kinds of maintenance:
      • Fixing bugs
      • Updating systems to accommodate changes in the environment
technical problem
TECHNICAL PROBLEM

HARDWARE?

CANNOT BE SCALED UP

OLD, REPLACEMENT PRRTS IS A PROBLEM

SOFTWARE?

ERRORS/SEDCURITY/SPEED/COST

MAINTENANCE

ADDITIONAL OR DIFFERENT OUTPUT

TELECOMMUNICATIONS?

DATABASE?

DYSFUNCTIONAL

OBSOLETE TECHNOLOGY?

NEW TECHNOLOGY IS AVAILABLE

organizational problem
ORGANIZATIONAL PROBLEM?

CHANGED OR NEW REGULATORY REQUIREMENTS

SYSTEMS CHANGES NEEDED TO CONFORM TO COMPANY RULES, POLICIES, CULTURE, UNION AGREEMENTS

CHANGES IN THE ORGANIZATION

E.G., A NEW PRODUCT LINE; NEW LOCATIONS; STRUCTURE REPORTING RELATIONSHIPS

CHANGES IN THE BUSINESS MODEL

E.G., NOW WANT BRICKS AND CLICKS

an opportunity not a problem
AN OPPORTUNITY, NOT A PROBLEM?

OPPORTUNITIES MAY BE SEEN BECAUSE OF BPR

NEWER TECHNOLOGY MAY BE FASTER, MORE RELIABLE

SAVE PROCESSING, LABOR COSTS

NEW CAPABILITIES PROVIDED BY NEW TECHNOLOGY MAY PROVIDE A COMPETITIVE ADVANTAGE

THE INTERNET/WWW

develop a systems specifications information requirements report
DEVELOP A SYSTEMS SPECIFICATIONS (INFORMATION REQUIREMENTS) REPORT

THE FINAL ANALYSIS STAGE ACTIVITY

MAY BE A VERY LONG DOCUMENT

MUST BE AGREED TO BY USERS

REPRESENTS THE SYSTEM OBJECTIVES

HOW MANY TRANSACTIONS PER HOUR?

HOW MUCH RELIABILITY?

WHAT KIND OF SECURITY?

WHO MUST RECEIVE REPORTS ABOUT WHAT?

ETC.

alternatives to conventional sdlcs
Alternatives to Conventional SDLCs

Four Possibilities:

  • Prototyping
  • Joint application design
  • Rapid application development
  • Object-oriented development
prototyping
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.
joint application design
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.
  • 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.
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.

E.g., Blue Cross & Blue Shield Develop an award-winning application using RAD.

Typical RAD packages include the following:

GUI development environment

Reusable components

Code generator

Programming language

Rapid Application Development
object oriented development
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.
component based development
Component-based Development
  • Componentsare 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.
business process modeling
Business Process Modeling
  • For IT professionals to appreciate an organizations technological needs, they need to know what the organization does and how it does it!
  • The Business Profile: Defines a company’s overall functions, processes, organization, products, services, customers, suppliers, competitors, constraints, and future direction.
  • In short, the business profile is a bird’s eye view of the relevant domain of an organizations operations
business process modeling1
Business Process Modeling
  • Business Models: Graphical representations of business functions, each business function is comprised of a series of business processes.
  • Business process: Describes specific events, tasks, and desired results.
  • A large organization will have many business models comprised of hundreds of business processes.
  • A system designer may be called in to evaluate a specific problem or design a global solution, either way, you need the big picture in order to estimate the implications of any modifications.
process handle sales order
Process: Handle Sales Order

Event:

Receive Sales Order

Sub process:

Check Customer Status

Sub process:

Verify Customer Credit

Result:

Completed Sales Order

Sub process:

Enter Customer Order Data