Information Systems A Business Approach

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Information SystemsA Business Approach

• Business Information Systems

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Data, Information, Knowledge And Wisdom
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What Is A Transaction?

• A transaction is a group of instructions that is
  indivisible or atomic in that it either
  executes completely or fails completely
• In the event of partial execution, instructions
  must be undone
• A transaction is not complete until it is
  committed onto stable storage - this gives a
  tradeoff between high performance and high
  reliability - TPSs have to be reliable!

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Transaction Processing Systems

• TPSs are the backbone of IS, well established
  systems.
• TPSs come in two main flavours, batch and real
  time.
• Batch Systems store up transaction data for later
  processing e.g. phone bills.
• Real Time Systems perform transactions as they
  arrive e.g. reservation systems.

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Examples TPSs

• Point of Sale Systems (POS) e.g. a super market -
  usually purchased as a turnkey system.
• Order Entry Systems - has POS functionality plus
  billing and shipping addresses, different inputs
  (EDI, WWW)
• greater potential for error than a POS.
• Reservation Systems e.g. airline and hotel
• General Ledger - some contention about whether
  general ledger qualifies as TPS
• most financial systems have the general ledger
  systems as their confluence

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Databases

• While TPSs provide the means of effecting
  transactions, transactions are usually recorded
  in a database
• A database is a logically related collection of
  organised data
• We make a distinction between data and metadata
• Database management systems (DBMS) carry out
• Data storage and retrieva
• Transaction/update atomicity
• user authentication and security
• Elimination of redundant data - update once and
  once only

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Data Hierarchy

• Database.
• Files may be integrated into databases.
• Records are grouped into files.
• Fields are grouped into records.
• Bytes are grouped into fields.
• Bits are grouped into bytes.

Increasing abstraction
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Data Hierarchy
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Database Organisation

• There are three main methods
• Hierarchical - older but excellent for well
  defined applications - not very flexible
• Network - has a high degree of flexibility but
  can be very hard to manage for complex
  applications
• Relational - more recent, good compromise, uses
  SQL, very adaptable, data are independent of
  software
• Even though the relational model is best there
  are many older databases still in use
• Object Oriented Databases are the next stage of
  database development

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The hierarchical database
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The Network database
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The Network database
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Management Information Systems (MIS)

• Five basic types
• Management Reporting Systems (MRS)
• Decision Support Systems (DSS)
• Expert Systems (ES)
• Executive Information Systems (EIS)
• Groupware

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Types Of MRS Report
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Decision Support Systems

• Use data from the past, from internal such as
  databases, datawarehouses and datamarts or
  external sources to model possible futures
• E.g. to assess the impact in cases where an
  employee is dismissed
• When using a datawarehouse, data-mining and OLAP
  tools are needed
• e.g. to establish most valuable customers

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Expert Systems

• These are intended to mimic human expertise in a
  specialised area
• Many domain experts may contribute to such
  systems
• ESs run 24 hrs per day and do not get tired
• They consist of knowledgebase, inference engine
  and user interface
• They tend to be used to augment rather than
  replace the human element
• Example systems include, aircraft docking,
  shipping systems, subway navigation systems

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Executive Information Systems

• Executive Information Systems (EIS) tend to have
  an enterprise wide focus and make extensive use
  of external data
• They resemble DSSs, but emphasise data synthesis,
  display trend and cause analysis rather than
  modelling which is the focus of most DSSs.
• EISs make use of hard and soft data, and allow
  human browsing without making queries
• Most EISs are slow in operation because they use
  relational databases for complex queries, some
  may need to carry out environmental sensing
• EISs frequently use groupware

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Groupware

• Groupware has four main functional areas in
  relation to information

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Groupware

• Communications may be
• Synchronous (real time - voice, video etc.)
• Asynchronous (via a bulletin board)
• 11, 1N or MN
• Groupware is more of an environment than a
  product. It is the enabling technology for Group
  DSS and knowledge management
• When combined with technologies such as
  intelligent agents it can simplify project and
  other management
• Potentially very high return on investment

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Groupware
An overview of a groupware-supported
purchasing system.
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Groupware Problems

• Information overload
• Inappropriate sharing of information
• Time wasting - since it easy to arrange meetings,
  staff tend to do so.
• State tracking - if staff do not update their
  electronic diary, meetings are arranged and they
  can not attend.
• Poor implementation strategies.

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Summary

• All ISs can be categorised according to the level
  at which they operate.
• Low level applications are well defined and
  structured and easy to automate (the systems
  replace people).
• High level applications tend to be unstructured
  and are difficult to automate (the systems tend
  to complement people).
• It is usually more cost effective to let people
  provide the intelligence and computers provide
  the efficiency.