SYSTEMS ANALYSIS AND DESIGN

CS 4

LEARNING OUTCOME

After going through this lesson, you should be able to: Understand a system Define Information System Analysis and Design Describe the different types of Information Systems. Describe the organizational roles, including Systems Analyst, involved in information systems development Describe the different phases of system developments life cycle

WHAT IS A SYSTEM?

Systems are created to solve problems.

An inter-related set of components, with an identifiable boundary, working together to achieve a goal or purpose.

FACULTY PERSONNEL UTILITY SECURITY

PSHS-EVC SYSTEM

WHAT IS A SYSTEM? (contd.)

Major components:

PROCESSINGINPUT OUTPUT

The Objective of the System demand that some output is produced as a result of processing the suitable inputs.

AN IS as a SYSTEM

INFORMATION SYSTEM (IS)

- is any combination of information technology and people's activities using that technology to support operations and management.- is frequently used to refer to the interaction between people, algorithmic processes, data and technology.

AN IS as a SYSTEM

INFORMATION SYSTEM (IS) COMPONENTS

Data Data Flow Processing Logic

AN IS as a SYSTEM

DATA vs INFORMATION

Data - raw facts about people, objects, and events in an organization. Information - Data that have been processed and presented in a form suitable for human interpretation.

AN IS as a SYSTEM

Data Flow - are groups of data that move through

a system and include a description of its source and destination.

INFORMATION SYSTEM (IS) COMPONENTS

ValidateCredit Card

Sale

Account Number& Transaction

Data

ValidAccount Number& Transaction

DataTransactions

Account Number& Transactions Prepare

Statement

Statement

AN IS as a SYSTEM

Processing Logic

- describes the steps in the transformation of the data and the events that trigger these steps.

INFORMATION SYSTEM (IS) COMPONENTS

DESIGN APPROACHES TO DEVELOP IS Process-oriented Approach - An overall strategy to information systems development that focuses on how and when data are moved through and changed by an Information System.

LIBRARYLENDINGSYSTEM

Book DataStudents

Data

STUDENTREGISTRYSYSTEM

Students Data

STUDENTGRADINGSYSTEM

Students Data

Grades Data

DESIGN APPROACHES TO DEVELOP IS Data-oriented Approach - an overall strategy of information systems development that focuses on the ideal organization of data rather than where and how data are used.

LIBRARYLENDINGSYSTEM

Book DataStudents

Data

STUDENTREGISTRYSYSTEM STUDENT

GRADINGSYSTEM

Grades Data

KEY DIFFERENCE BET. P-O & D-O APPROACHESDESIGN APPROACHES TO DEVELOP IS

CHARACTERISTICS PROCESS-ORIENTED DATA-ORIENTED

System focus What the system is supposed to do and when

Data the system needs to operate

Design Stability Limited, as business processes and the applications that support them change constantly

More enduring, as the data needs of an organization do not change rapidly

Data Organization Data files designed for each individual application

Data files designed for the enterprise

State of the data Much uncontrolled duplication

Limited, controlled duplication

TYPES OF INFORMATION SYSTEM

Transaction Processing Systems (TPS) Management Information Systems (MIS) Decision Support Systems (DSS) Expert Systems (ES)

TYPES OF INFORMATION SYSTEM

Transaction Processing Systems (TPS) - automate the handling of data about business activities or transactions, which can be thought of as simple, discrete events in the life of the organization. Management Information Systems (MIS) - takes the relatively raw data available through a TPS and converts them into a meaningful aggregated form that managers need.

TYPES OF INFORMATION SYSTEM Decision Support Systems (DSS) - Instead of providing summaries of data, it provides an interactive environment in which decision makers can quickly manipulate data and models of business operations. Expert Systems (ES) - used synonymously with KBS it attempts to codify and manipulate knowledge rather than information. - Users communicate with an ES through an interactive dialogue.

Systems Development for Different IS TypesDESIGN APPROACHES TO DEVELOP IS

IS Type IS Characteristics System Development Methods

Transaction Processing System

High volume, data capture focus; goal is efficiency of data movement and processing and interfacing different TPSs.

Process-orientation; concern with capturing, validating, and storing data and with moving data between each required step

Management Info. System

Draws on Diverse yet predictable data resources to aggregate and summarized data; may involve forecasting future data from historical trends and business knowledge

Data-orientation; concern with understanding relationships between data so they can be accessed and summarized in a variety of ways; builds a model of data that supports a variety of uses.

Systems Development for Different IS TypesDESIGN APPROACHES TO DEVELOP IS

IS Type IS Characteristics System Development Methods

Decision Support System

Provides guidance in identifying problems, finding and evaluating alternative solutions, and selecting or comparing alternatives; potentially involves groups of decision makers; often involves semi-structured problems and the need to access data at different levels of detail

Data and Decision logic orientations; design of user dialogue; group communication may also be key and access to unpredictable data may be necessary; nature of systems require iterative development and almost constant updating

Expert System Provides expert advice by asking users a sequence of questions dependent on prior answers that lead to a conclusion or recommendation

A specialized decision logic-orientation in which knowledge is elicited from experts and described by rules or other forms

WHAT IS ISAD?

Information System Analysis and Design

- The complex organizational process whereby computer-based information systems are developed and maintained.

- is a step-by-step process for developing high-quality information systems.

- an organizational improvement process.

ISAD RESULT

APPLICATION SOFTWARE

- a computer software designed to support a specific organizational function or process.

Example: Inventory management Payroll Market Analysis Traffic Analysis Criminal Profiling

PLAYERS IN THE SYSTEM GAME

Regardless of how an organization structures its information systems department, systems Development is a team effort.In general, those involved in systems dev't.Include:

IS Managers Systems Analysts Programmers End Users Other IS Managers/Technicians

PLAYERS IN THE SYSTEM GAME

CHARACTERISTICS OF SUCCESSFUL TEAM

• Diversity in backgrounds, skills, and goals• Tolerance of diversity, uncertainty, ambiguity• Clear and complete communication• Trust• Mutual Respect and putting one's own views second to the team• Reward structure that promotes shared responsibility and accountability

ASSIGNMENT:

SUBMIT A DESCRIPTION OF THE ROLES OF EACH IS development key players.

ACTIVITY:

INFORMATION SYSTEM USERS & THEIR NEEDS

INFORMATION SYSTEM USERS & THEIR NEEDS

IMPACT OF THE INTERNET ON IS Development

- trends of Internet-based commerce (e-commerce or I-commerce)- Electronic Data Interchange (EDI) enabled computer- To-computer transfer of data between companies- The development of Extensible Markup Language (XML) enabled company-to-company traffic to Migrate to the Internet which offered standard Protocols, universal availability, and low Communication costs.

ACTIVITY

Computers perform many jobs that previously were done by people.

Will computer-based transactions and expanded e-commerce eventually replace person-to-person contact?

From a customer’s point of view, is this better? Why or why not?