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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
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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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?