Information Systems Introduction

8/8/2019 Information Systems Introduction

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TDT4175 Information systems

Introduction

People:

Jon Atle Gulla

Csaba Veres

Guttorm Sindre

Darijus Strasunskas

Introduction

What is an Information System?

What sorts of Information Systems are there?

How do you build/acquire one?

The role of visual modeling languages.

Information systems

An information system (IS) is an arrangement ofpeople, data, processes, communications, andinformation technology that interact to support andimprove day-to-day operations in a business, as wellas support the problem-solving and decision-makingneeds of management and users.

Information technology

is a contemporary term thatdescribes the combination of computer technology(hardware and software) with telecommunicationstechnology (data, image, and voice networks).

Examples

reservation system for planes, ships, etc.

navigation system for planes, ships, etc.

accounting systems for banks

inventory / store room

payroll invoicing / billing


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Newspaper production

Preparation

ideas, tips, information gathering

editorial work

subject matter / content

text, photos

advertising

proofs, layout

distribution

archiving

A possible solution

groupware

e.g. Lotus Notes

discussion groups, database interface

standardised forms

automatise various tasks

email

support for shared real-time data

focus on integration

Information Systems (cont.)

IS collect, store, transform, and distribute

information products

a technical system implemented with computer

and telecommunications technology

a social system that deals with organisations

information needs


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A stakeholder is any person who has an interest in an existing or

new information system. Stakeholders can be technical or

nontechnical workers.

For information systems, the stakeholders can be classified as:

System owners

System users

Systems analysts *

System designers

System builders

IT vendors and consultants *

Stakeholders

A systems analyst studies the problems and needs of anorganization to determine how people, data, processes,communications, and information technology can bestaccomplish improvements for the business. When informationtechnology is used, the analyst is responsible for:

The efficient capture of data from its business source,

The flow of that data to the computer,

The processing and storage of that data by the computer, and

The flow of useful and timely in formation back to the businessand its people.

Analysts

Analysis

Find out current practices

Communication

Research

Problem solving

Find out requirements/deficiencies/needs

As above, plus

Attention to detail

Analysis 2

Know about possible technical solutions

Decide which solution best

Solutions appropriate for the problem

Off the shelf?

Custom made?

What sort of technical solution?

How should it be built?


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Analysts make decisions

Weighted matrices

Designers and builders

System designers translate system users business requirements

and constraints into technical solutions. They design the

computer files, databases, inputs, outputs, screens, networks, and

programs that will meet the system users requirements.

System builders construct the information system componentsbased on the design specifications from the system designers. In

many cases, the system designer and builder for a component are

one and the same.

IS more formally An IS is a body ofsigns, and the associatedprocesses for

storing and transforming the signs, and for exchanging signs

with the exterior of the information system.

Each sign reflects some property of the Universe of

Discourse (UoD) , which is the domain of individuals

referred to by the IS, that is, signs denote referents in the

UoD.

UoD

IS

Body of

signsSign

Processes

denotationExterior ofInformation

System

sign

exchange


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Data, information, and

knowledge Data are raw facts about the organization and its

business transactions. Most data items have littlemeaning and use by themselves.

Information is data that has been refined andorganized by processing and purposeful intelligence.The latter, purposeful intelligence, is crucial to thedefinitionPeople provide the purpose and theintelligence that produces true information.

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Data and informationInformation is data that has been put into context

What kinds of IS?

Front-officeinformation systems support businessfunctions that reach out to customers (orconstituents).

Marketing

Sales

Customer management

Back-officeinformation systems support internalbusiness operations and interact with suppliers (of

materials, equipment, supplies, and services). Human resources Financial management

Manufacturing

Inventory control


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Classes of IS

Many different sorts of systems exist in

practice and research

Many different ways to classify them

Who the intended users are

What functionality they provide

What purpose they serve

MIS

A management information system (MIS)

is an information system application that

provides for management-oriented

reporting. These reports are usually

generated on a predetermined schedule and

appear in a prearranged format. Analysis of information, generation of

requested reports, solving of structured

problems

EIS

An Executive Information System extract,

filter, compress, and track critical data

On line status access, trend analysis, exception

reporting, and drill-down

User friendly

Easy to access, built in intelligence

ESS

An Executive Support System adds extra

capabilities to EIS

Support for electronic communication

Data analysis with spreadsheets, query languages

Organizing tools (calendars, schedulers, etc.)


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DSS

A decision support system provides its users withdecision-oriented information whenever a decision-making situation arises.

Includes decision aids for the analysis ofsemistructured problems for individuals

What-if scenarios

Emphasis moves away from knowing to doing

GDSS

A Group Decision Support System supports

decision making operations for groups

Includes information sharing and exchange for

decision support

Support for negotiations and conflict resolution

Shared understanding (models, shared workspaces,

etc.)

Structures decision modeling

EMS

Electronic Meeting Systems provide

infrastructure for supporting group work

Synchronous and asynchronous

communications

Shared software, views

Some of these also included in GDSS

Expert Systems

Anexpert system is a programmed decision-making

information system that captures and reproduces the

knowledge and expertise of an expert problem solver

or decision maker and then simulates the thinking

or actions of that expert.

Expert systems are implemented withartificialintelligence technology that captures, stores, and

provides access to the reasoning of the experts.


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Expert Systems 2

An ES gives advice based on knowledge, not

just information

Solves new problems, and works with users

not just for users

Not suitable for all domains/problems

OIS

Office Information Systems support

document-related, procedural and

communication issues of office work

Document processing, printing, etc.

Office procedures, e.g. Enrolling new students,

filling orders

Office tasks, e.g. Keeping files well organized,

updating inventory, etc.

A Functional Taxonomy

Categorize systems in terms of their

functional capability

Information support

Decision support

Communication support

Functional Taxonomy 2

Information System Information Support Decision Support Communication Support

MIS High Low Low

EIS High Low Low

ESS High Low Medium

DSS Medium High Low

GDSS Medium High High

EMS Medium Low High

ES Medium High Low

OIS High Low High


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ERP

AnEnterprise resource planning (ERP) softwareproduct is a fully integrated information system thatspans most basic business functions required by amajor corporation. An ERP product is built around acommon database shared these business functions.Examples of ERP software vendors include.

Oracle

Peoplesoft

SAP

E-commerce

Electronic commerce (e-commerce or EC) involvesconducting both internal and external business overthe Internet, intranets, and extranets.

Electronic commerce includes the buying and selling of

goods and services, the transfer of funds, and the

simplification of day-to-day business processes all

through digital communications.

Three basic types of electronic commerce applications

include:

Marketing

Business-to-consumer (B2C)

Business-to-business (B2B)

IS Development

Techniques, tools, methods, strategiesTechniques and Tools

Techniques are skills designed to do a

specific job

e.g. class diagrams, sequence diagrams

Tools

Software artefacts that make it easier to use the

techniques Drawing

Syntax checking

Integration across stages (CASE tools)


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Methods

Careful selection of techniques appropriate

for a particular task

SSADM (Structured Systems Analysis and Design

Method) is a method embodied in a particular case

tool

Rational Unified Process (RUP) combines UML

techniques in specific order to accomplish

analysis/design

Strategies

A high level, organizational stance towards

methods for particular objectives

RAD for small projects

RUP for intermediate projects

Approaches

Approaches reflect different

conceptualizations of the way that work is

performed, information processed, and

software constructed

Groups of methods are often tied to particular

approaches Approaches strongly influence the kinds of

techniques that a given method employs

Approaches 2

Structured Analysis

What a system does, not how

Logical rather than physical (abstracts away from the

current physical means of accomplishing tasks)

Assumes stable procedures

Top-down functional decomposition of the system


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Approaches 3

Object-oriented

Modular

Data + process

Approaches 4

Each approach has different perspectives

within it

Structured Analysis

Processes and data flows

Data stores

Object Oriented

Data and method combined

Perspectives

Data

information structure

Process

information flow, information processing

Object

interacting objects

Data


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Process

Actor

Process

data flow

Object oriented

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STUDENT

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COURSE

+Add()+Drop()+Complete()+Change Grade()

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IS development: the problem,

and the role for modelling

many stakeholders / actors to consult

developer must see the whole picture

complex

the many actors have many needs

interface to external systems / internet

security


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Some common problems

delays in product delivery

exceed projected cost

system fails to meet user requirements

unreliable system needs constantmaintenance

badly structured and poorly documentedsystems make use and maintenenacedifficult

Why so difficult?

I believe the hard part of building software to be the s pecification, the design andtesting of this conceptual construct

[Brooks, No Silver Bullet]

difficulties: communication, comprehension andcollaboration between the various actors

IS is abstract, unknown, complex

conceptual models can help communication andcollaboration between all actors

IS models

a level of description that is useful to all

stakeholders

users and managers understand usability and

business processes

developers understand requirements and

design needs

shared conceptual models

Communication

Basis for evaluating and validating duringearly phases

Basis for implementation smoothing the transition

Basis for documentation

IS

Model

Communication

& Interaction


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Abstract models

The world The model The artifact

S ytems analysis Systems design

But artifacts are worldly things

too

The model

The world

The artifact

Sytems analysis

Systems design

Information Systems are artifacts

The model

Universe of Discourse (UoD)

Information

system

Requirements

engineering

IS design

What is a good model?

Easy to understand

user-oriented concepts and constructs

informal and formal descriptions readable

unambiguous

clear

intuitive

Powerful

fully expressive

good resolution


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good model

specification should be checkable and

testable

free from conflict

accurate reflection of the problem

specification should be easy to change

good model captures

What?

The functional

aspect

How?

The technical

aspect

Who?

The operational

aspect

A simple example

Spray and tree diagrams

Capture and Organize important information

Transport

RoadPlane

Speed

Fuel

BusFare

Car

Bus stop

Airport

Luggage

Transport

RoadPlane

Speed

FuelBus

Fare

Car

Bus stop

Airport

Luggage

Organize

Fare

Fare

Fuel

Fuel

Diesel

Petrol

Route

Bus stop


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Tree diagram

Transport

Road

Plane

Speed-limit

Bus

Fare

Car

Airport

Luggage

Fare

Fuel

FuelDiesel

Petrol

Route

Bus stop

Air

We are developing a

particular logical

perspective

Is it a good one?

Documents

Information Systems Introduction